From 475673ffd13438138f744f56893e809073843c62 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Wed, 19 Oct 2022 17:57:58 +0200
Subject: [PATCH 01/24] draft implementation for block opcode

---
 .../runtime/src/interpreter/interpreter.ts    | 20 +++++++
 .../runtime/src/interpreter/opcode-list.ts    | 54 +++++++++++++++++--
 packages/runtime/src/interpreter/opcode.ts    |  3 +-
 packages/runtime/src/lib/constants.ts         |  2 +
 .../test/src/interpreter/opcode-list.ts       | 22 ++++++++
 5 files changed, 95 insertions(+), 6 deletions(-)

diff --git a/packages/runtime/src/interpreter/interpreter.ts b/packages/runtime/src/interpreter/interpreter.ts
index 1ac06666f..a53b72aea 100644
--- a/packages/runtime/src/interpreter/interpreter.ts
+++ b/packages/runtime/src/interpreter/interpreter.ts
@@ -17,6 +17,7 @@ import {
 	DEFAULT_STACK_ELEM,
 	LOGIC_SIG_MAX_COST,
 	MaxTEALVersion,
+	MaxTxnLife,
 	MinVersionSupportC2CCall,
 	TransactionTypeEnum,
 } from "../lib/constants";
@@ -595,4 +596,23 @@ export class Interpreter {
 		}
 		return result;
 	}
+
+	//TODO:add description
+	assertRoundIsAvailable(round: number): void {
+		let firstAvail = this.runtime.ctx.tx.lv - MaxTxnLife - 1;
+		if (firstAvail > this.runtime.ctx.tx.lv || firstAvail === 0) {
+			// early in chain's life
+			firstAvail = 1;
+		}
+		//TODO: what happends if FirstValid is undefined?
+		let lastAvail = this.runtime.ctx.tx.fv === undefined ? 0 : this.runtime.ctx.tx.fv - 1;
+		if (this.runtime.ctx.tx.fv === undefined || lastAvail > this.runtime.ctx.tx.fv) {
+			// txn had a 0 in FirstValid
+			lastAvail = 0; // So nothing will be available
+		}
+		if (firstAvail > round || round > lastAvail) {
+			throw new Error();
+			// throw error ("round %d is not available. It's outside [%d-%d]", r, firstAvail, lastAvail)
+		}
+	}
 }
diff --git a/packages/runtime/src/interpreter/opcode-list.ts b/packages/runtime/src/interpreter/opcode-list.ts
index c44abfd3a..288b859a0 100644
--- a/packages/runtime/src/interpreter/opcode-list.ts
+++ b/packages/runtime/src/interpreter/opcode-list.ts
@@ -84,7 +84,8 @@ import {
 } from "../types";
 import { Interpreter } from "./interpreter";
 import { Op } from "./opcode";
-const bn254 = require("rustbn.js");// eslint-disable-line @typescript-eslint/no-var-requires
+const bn254 = require("rustbn.js"); // eslint-disable-line @typescript-eslint/no-var-requires
+import { randomBytes } from "crypto";
 
 // Opcodes reference link: https://developer.algorand.org/docs/reference/teal/opcodes/
 
@@ -4354,10 +4355,10 @@ export class ITxnSubmit extends Op {
 			const signedTransactions: algosdk.SignedTransaction[] = execParams.map((txnParam) =>
 				types.isExecParams(txnParam)
 					? {
-						sig: Buffer.alloc(5),
-						sgnr: Buffer.from(algosdk.decodeAddress(contractAddress).publicKey),
-						txn: webTx.mkTransaction(txnParam, mockSuggestedParams(txnParam.payFlags, 1)),
-					}
+							sig: Buffer.alloc(5),
+							sgnr: Buffer.from(algosdk.decodeAddress(contractAddress).publicKey),
+							txn: webTx.mkTransaction(txnParam, mockSuggestedParams(txnParam.payFlags, 1)),
+					  }
 					: txnParam
 			);
 			this.interpreter.runtime.ctx.processTransactions(signedTransactions);
@@ -5210,6 +5211,7 @@ export class Json_ref extends Op {
 		return this.computeCost();
 	}
 }
+//TODO:add description
 export class Bn254Add extends Op {
 	readonly line: number;
 	/**
@@ -5233,6 +5235,7 @@ export class Bn254Add extends Op {
 		return this.computeCost();
 	}
 }
+//TODO:add description
 export class Bn254ScalarMul extends Op {
 	readonly line: number;
 	/**
@@ -5256,6 +5259,7 @@ export class Bn254ScalarMul extends Op {
 		return this.computeCost();
 	}
 }
+//TODO:add description
 export class Bn254Pairing extends Op {
 	readonly line: number;
 	/**
@@ -5280,3 +5284,43 @@ export class Bn254Pairing extends Op {
 		return this.computeCost();
 	}
 }
+//TODO:add description
+export class Block extends Op {
+	readonly line: number;
+	readonly field: string;
+	readonly interpreter: Interpreter;
+	//TODO:add description
+	/**
+	 * @param args
+	 * @param line line number in TEAL file
+	 */
+	constructor(args: string[], line: number, interpreter: Interpreter) {
+		super();
+		assertLen(args.length, 1, line);
+		const argument = args[0];
+		if (argument === "BlkSeed" || argument === "BlkTimestamp") {
+			this.field = argument;
+		} else {
+			throw new Error();
+			//throw an error, unknown field
+		}
+		this.line = line;
+		this.interpreter = interpreter;
+	}
+	execute(stack: TEALStack): number {
+		this.assertMinStackLen(stack, 1, this.line);
+		const round = this.assertBigInt(stack.pop(), this.line);
+		this.interpreter.assertRoundIsAvailable(Number(round));
+		let result: StackElem;
+		if (this.field === "BlkSeed") {
+			//mock the seed by generating a 32 bytes long psuedo-random
+			result = randomBytes(20);
+		} else {
+			//"BlkTimestamp"
+			//seconds since epoch
+			result = BigInt(Math.round(new Date().getTime() / 1000));
+		}
+		stack.push(result);
+		return this.computeCost();
+	}
+}
diff --git a/packages/runtime/src/interpreter/opcode.ts b/packages/runtime/src/interpreter/opcode.ts
index 104424d6d..421f3108b 100644
--- a/packages/runtime/src/interpreter/opcode.ts
+++ b/packages/runtime/src/interpreter/opcode.ts
@@ -193,13 +193,14 @@ export abstract class Op {
 	 * @param index Index
 	 * @param line line number in TEAL file
 	 */
-	assert64BitIndex(index: bigint, line: number): void {
+	assert64BitIndex(index: bigint, line: number): bigint {
 		if (index > MAX_UINT6) {
 			throw new RuntimeError(RUNTIME_ERRORS.TEAL.SET_BIT_INDEX_ERROR, {
 				index: index,
 				line: line,
 			});
 		}
+		return index;
 	}
 
 	/**
diff --git a/packages/runtime/src/lib/constants.ts b/packages/runtime/src/lib/constants.ts
index c52247210..dc52439f1 100644
--- a/packages/runtime/src/lib/constants.ts
+++ b/packages/runtime/src/lib/constants.ts
@@ -56,6 +56,8 @@ export const MAX_LOCAL_SCHEMA_ENTRIES = 16;
 export const MAX_INPUT_BYTE_LEN = 64;
 export const MAX_OUTPUT_BYTE_LEN = 128;
 
+export const MaxTxnLife = 1000; //TODO:add description
+
 export const ZERO_ADDRESS = new Uint8Array(32);
 export const ZERO_ADDRESS_STR = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAY5HFKQ";
 const zeroUint64 = 0n;
diff --git a/packages/runtime/test/src/interpreter/opcode-list.ts b/packages/runtime/test/src/interpreter/opcode-list.ts
index ad3370104..bc70482b6 100644
--- a/packages/runtime/test/src/interpreter/opcode-list.ts
+++ b/packages/runtime/test/src/interpreter/opcode-list.ts
@@ -45,6 +45,7 @@ import {
 	BitwiseNot,
 	BitwiseOr,
 	BitwiseXor,
+	Block,
 	Bn254Add,
 	Bn254Pairing,
 	Bn254ScalarMul,
@@ -7563,4 +7564,25 @@ describe("Teal Opcodes", function () {
 			assert.equal(expectedResult, stack.pop());
 		});
 	});
+	describe.only("block op", function () {
+		const stack = new Stack<StackElem>();
+		let interpreter: Interpreter;
+		this.beforeEach(function () {
+			interpreter = new Interpreter();
+			interpreter.runtime = new Runtime([]);
+			interpreter.runtime.ctx.tx = TXN_OBJ;
+			interpreter.tealVersion = MaxTEALVersion; // set tealversion to latest (to support all tx fields)
+		});
+
+		it("Should fail when accesing two behind FirstVaild because LastValid is 1000 after", function () {
+			stack.push(BigInt(TXN_OBJ.fv - 2));
+			const op = new Block(["BlkTimestamp"], 1, interpreter);
+			assert.throws(() => op.execute(stack));
+		});
+		it("Should allow to acces two behind FirstValid", function () {
+			stack.push(BigInt(TXN_OBJ.fv - 1));
+			const op = new Block(["BlkTimestamp"], 1, interpreter);
+			assert.doesNotThrow(() => op.execute(stack));
+		});
+	});
 });

From cf2889f63c65bbd3418f69d11efcf73e8b672606 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Wed, 19 Oct 2022 21:17:37 +0200
Subject: [PATCH 02/24] better way to mock the seed and timestamp

---
 packages/runtime/src/interpreter/opcode-list.ts | 9 ++++++---
 packages/runtime/src/lib/constants.ts           | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/packages/runtime/src/interpreter/opcode-list.ts b/packages/runtime/src/interpreter/opcode-list.ts
index 288b859a0..c0a4f01f7 100644
--- a/packages/runtime/src/interpreter/opcode-list.ts
+++ b/packages/runtime/src/interpreter/opcode-list.ts
@@ -29,6 +29,7 @@ import {
 	ALGORAND_MAX_LOGS_LENGTH,
 	AppParamDefined,
 	AssetParamMap,
+	BlockFinalizationTime,
 	GlobalFields,
 	ITxArrFields,
 	json_refTypes,
@@ -86,6 +87,7 @@ import { Interpreter } from "./interpreter";
 import { Op } from "./opcode";
 const bn254 = require("rustbn.js"); // eslint-disable-line @typescript-eslint/no-var-requires
 import { randomBytes } from "crypto";
+import * as base32 from "hi-base32";
 
 // Opcodes reference link: https://developer.algorand.org/docs/reference/teal/opcodes/
 
@@ -5314,11 +5316,12 @@ export class Block extends Op {
 		let result: StackElem;
 		if (this.field === "BlkSeed") {
 			//mock the seed by generating a 32 bytes long psuedo-random
-			result = randomBytes(20);
+			result = randomBytes(32);
 		} else {
 			//"BlkTimestamp"
-			//seconds since epoch
-			result = BigInt(Math.round(new Date().getTime() / 1000));
+			//seconds since epoch - rounds, assuming one round(block) = 2.5s truncated to 2s (BigInt)
+			result =
+				BigInt(Math.round(new Date().getTime() / 1000)) - round * BigInt(BlockFinalizationTime);
 		}
 		stack.push(result);
 		return this.computeCost();
diff --git a/packages/runtime/src/lib/constants.ts b/packages/runtime/src/lib/constants.ts
index dc52439f1..c262f8c1d 100644
--- a/packages/runtime/src/lib/constants.ts
+++ b/packages/runtime/src/lib/constants.ts
@@ -57,6 +57,7 @@ export const MAX_INPUT_BYTE_LEN = 64;
 export const MAX_OUTPUT_BYTE_LEN = 128;
 
 export const MaxTxnLife = 1000; //TODO:add description
+export const BlockFinalizationTime = 2.5; // block finalization time in seconds
 
 export const ZERO_ADDRESS = new Uint8Array(32);
 export const ZERO_ADDRESS_STR = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAY5HFKQ";

From 8d4e7c88874a17e7e2688a8c3bfbfeddda42f5c1 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Thu, 20 Oct 2022 22:30:46 +0200
Subject: [PATCH 03/24] changing the constans

---
 packages/runtime/src/interpreter/opcode-list.ts     |  3 +--
 packages/runtime/src/lib/constants.ts               |  2 +-
 .../runtime/test/src/interpreter/opcode-list.ts     | 13 +++++++++++++
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/packages/runtime/src/interpreter/opcode-list.ts b/packages/runtime/src/interpreter/opcode-list.ts
index c0a4f01f7..c373473ed 100644
--- a/packages/runtime/src/interpreter/opcode-list.ts
+++ b/packages/runtime/src/interpreter/opcode-list.ts
@@ -5320,8 +5320,7 @@ export class Block extends Op {
 		} else {
 			//"BlkTimestamp"
 			//seconds since epoch - rounds, assuming one round(block) = 2.5s truncated to 2s (BigInt)
-			result =
-				BigInt(Math.round(new Date().getTime() / 1000)) - round * BigInt(BlockFinalizationTime);
+			result = BigInt(Math.round(new Date().getTime() / 1000)) - round * BlockFinalizationTime;
 		}
 		stack.push(result);
 		return this.computeCost();
diff --git a/packages/runtime/src/lib/constants.ts b/packages/runtime/src/lib/constants.ts
index c262f8c1d..600687404 100644
--- a/packages/runtime/src/lib/constants.ts
+++ b/packages/runtime/src/lib/constants.ts
@@ -57,7 +57,7 @@ export const MAX_INPUT_BYTE_LEN = 64;
 export const MAX_OUTPUT_BYTE_LEN = 128;
 
 export const MaxTxnLife = 1000; //TODO:add description
-export const BlockFinalizationTime = 2.5; // block finalization time in seconds
+export const BlockFinalizationTime = 2n; // block finalization time in seconds truncated down
 
 export const ZERO_ADDRESS = new Uint8Array(32);
 export const ZERO_ADDRESS_STR = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAY5HFKQ";
diff --git a/packages/runtime/test/src/interpreter/opcode-list.ts b/packages/runtime/test/src/interpreter/opcode-list.ts
index bc70482b6..2d89edc78 100644
--- a/packages/runtime/test/src/interpreter/opcode-list.ts
+++ b/packages/runtime/test/src/interpreter/opcode-list.ts
@@ -7567,6 +7567,7 @@ describe("Teal Opcodes", function () {
 	describe.only("block op", function () {
 		const stack = new Stack<StackElem>();
 		let interpreter: Interpreter;
+		const LAST_VALID = 259820n;
 		this.beforeEach(function () {
 			interpreter = new Interpreter();
 			interpreter.runtime = new Runtime([]);
@@ -7584,5 +7585,17 @@ describe("Teal Opcodes", function () {
 			const op = new Block(["BlkTimestamp"], 1, interpreter);
 			assert.doesNotThrow(() => op.execute(stack));
 		});
+		it("Should return two different seeds for to different rounds", function () {
+			const op = new Block(["BlkTimestamp"], 1, interpreter);
+			//first round
+			stack.push(LAST_VALID - 2n);
+			op.execute(stack);
+			const seedRound1 = stack.pop();
+			//second round
+			stack.push(LAST_VALID - 3n);
+			op.execute(stack);
+			const seedRound2 = stack.pop();
+			assert.notEqual(seedRound1, seedRound2);
+		});
 	});
 });

From 34dcac2fbc792038c0ec12e16bb628b6c129ad5b Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Wed, 26 Oct 2022 19:46:52 +0200
Subject: [PATCH 04/24] add blocks to runtime

---
 packages/runtime/src/errors/errors-list.ts    | 12 ++++++
 .../runtime/src/interpreter/opcode-list.ts    | 10 ++---
 packages/runtime/src/runtime.ts               | 37 ++++++++++++++++++-
 packages/runtime/src/types.ts                 |  6 +++
 .../test/src/interpreter/opcode-list.ts       |  2 +-
 5 files changed, 59 insertions(+), 8 deletions(-)

diff --git a/packages/runtime/src/errors/errors-list.ts b/packages/runtime/src/errors/errors-list.ts
index 81a00eb54..7f205f7b3 100644
--- a/packages/runtime/src/errors/errors-list.ts
+++ b/packages/runtime/src/errors/errors-list.ts
@@ -596,6 +596,18 @@ const runtimeGeneralErrors = {
 		description:
 			"Provided multisignature is invalid and was not able to authenticate the transaction",
 	},
+	PRODUCE_BLOCK: {
+		number: 1322,
+		message: "Produce block",
+		title: "Produce block",
+		description: "Runtime failed while trying to produce new block",
+	},
+	INVALID_BLOCK: {
+		number: 1323,
+		message: "Invalid block",
+		title: "Invalid block",
+		description: "Provided round does not correspond to any existing block",
+	}
 };
 
 const transactionErrors = {
diff --git a/packages/runtime/src/interpreter/opcode-list.ts b/packages/runtime/src/interpreter/opcode-list.ts
index c373473ed..3263c133a 100644
--- a/packages/runtime/src/interpreter/opcode-list.ts
+++ b/packages/runtime/src/interpreter/opcode-list.ts
@@ -5311,16 +5311,16 @@ export class Block extends Op {
 	}
 	execute(stack: TEALStack): number {
 		this.assertMinStackLen(stack, 1, this.line);
-		const round = this.assertBigInt(stack.pop(), this.line);
-		this.interpreter.assertRoundIsAvailable(Number(round));
+		const round = Number(this.assertBigInt(stack.pop(), this.line));
+		this.interpreter.assertRoundIsAvailable(round);
+		const block = this.interpreter.runtime.getBlock(round);
 		let result: StackElem;
 		if (this.field === "BlkSeed") {
-			//mock the seed by generating a 32 bytes long psuedo-random
-			result = randomBytes(32);
+			result = block.seed;
 		} else {
 			//"BlkTimestamp"
 			//seconds since epoch - rounds, assuming one round(block) = 2.5s truncated to 2s (BigInt)
-			result = BigInt(Math.round(new Date().getTime() / 1000)) - round * BlockFinalizationTime;
+			result = block.timestamp;
 		}
 		stack.push(result);
 		return this.computeCost();
diff --git a/packages/runtime/src/runtime.ts b/packages/runtime/src/runtime.ts
index 8e12a1ab2..ac4dbc579 100644
--- a/packages/runtime/src/runtime.ts
+++ b/packages/runtime/src/runtime.ts
@@ -7,9 +7,10 @@ import algosdk, {
 	SignedTransaction,
 	Transaction,
 } from "algosdk";
-import { exec } from "child_process";
+import { randomBytes } from "crypto";
 import cloneDeep from "lodash.clonedeep";
 import nacl from "tweetnacl";
+import { bigint, map } from "zod";
 
 import { AccountStore, defaultSDKAccounts, RuntimeAccount } from "./account";
 import { Ctx } from "./ctx";
@@ -20,6 +21,7 @@ import { compareArray } from "./lib/compare";
 import {
 	ALGORAND_ACCOUNT_MIN_BALANCE,
 	ALGORAND_MAX_TX_ARRAY_LEN,
+	BlockFinalizationTime,
 	MAX_APP_PROGRAM_COST,
 	TransactionTypeEnum,
 	ZERO_ADDRESS_STR,
@@ -35,6 +37,7 @@ import {
 	ASADeploymentFlags,
 	ASAInfo,
 	AssetHoldingM,
+	Block,
 	Context,
 	EncTx,
 	ExecutionMode,
@@ -76,6 +79,7 @@ export class Runtime {
 			appCounter: ALGORAND_MAX_TX_ARRAY_LEN, // initialize app counter with 8
 			assetCounter: ALGORAND_MAX_TX_ARRAY_LEN, // initialize asset counter with 8
 			txReceipts: new Map<string, TxReceipt>(), // receipt of each transaction, i.e map of {txID: txReceipt}
+			blocks: new Map<number, Block>(),
 		};
 
 		this._defaultAccounts = this._setupDefaultAccounts();
@@ -88,7 +92,8 @@ export class Runtime {
 
 		// context for interpreter
 		this.ctx = new Ctx(cloneDeep(this.store), <EncTx>{}, [], [], this);
-		this.round = 2;
+		this.round = 1;
+		this.produceBlock();
 		this.timestamp = 1;
 	}
 
@@ -1162,4 +1167,32 @@ export class Runtime {
 	sendTxAndWait(transactions: SignedTransaction[]): TxnReceipt[] {
 		return this.executeTx(transactions);
 	}
+
+	produceBlock() {
+		let timestamp: bigint | undefined;
+		let seed: Uint8Array | undefined;
+		if (this.store.blocks.size === 0) { //create genesis block
+			seed = randomBytes(32);
+			timestamp = BigInt(Math.round(new Date().getTime() / 1000));
+		} else { //add another block
+			const lastBlock = this.store.blocks.get(this.round);
+			if (lastBlock !== undefined) {
+				seed = randomBytes(32);
+				timestamp = lastBlock.timestamp + 4n;
+				this.round += 1;// we move to new a new round
+			}
+		}
+		if (timestamp !== undefined && seed !== undefined) {
+			this.store.blocks.set(this.round, { timestamp, seed });
+		}
+		throw new RuntimeError(RUNTIME_ERRORS.GENERAL.PRODUCE_BLOCK); 
+	}
+
+	getBlock(round: number): Block {
+		const block = cloneDeep(this.store.blocks.get(round));
+		if (block !== undefined) {
+			return block;
+		}
+		throw new RuntimeError(RUNTIME_ERRORS.GENERAL.INVALID_BLOCK);
+	}
 }
diff --git a/packages/runtime/src/types.ts b/packages/runtime/src/types.ts
index 8fe1c73e0..19691d767 100644
--- a/packages/runtime/src/types.ts
+++ b/packages/runtime/src/types.ts
@@ -102,6 +102,7 @@ export interface State {
 	appCounter: number;
 	assetCounter: number;
 	txReceipts: Map<string, TxReceipt>; // map of {txID: txReceipt}
+	blocks: Map<number, Block>, // map of{round, block}
 }
 
 export interface DeployedAssetInfo {
@@ -432,3 +433,8 @@ export interface AppInfoReceipt extends DeployedAssetInfoReceipt {
 	logs?: Uint8Array[];
 	gas?: number;
 }
+
+export interface Block {
+	timestamp: bigint; //uint64
+	seed: Uint8Array; //[]byte
+}
diff --git a/packages/runtime/test/src/interpreter/opcode-list.ts b/packages/runtime/test/src/interpreter/opcode-list.ts
index 2d89edc78..242be0085 100644
--- a/packages/runtime/test/src/interpreter/opcode-list.ts
+++ b/packages/runtime/test/src/interpreter/opcode-list.ts
@@ -7575,7 +7575,7 @@ describe("Teal Opcodes", function () {
 			interpreter.tealVersion = MaxTEALVersion; // set tealversion to latest (to support all tx fields)
 		});
 
-		it("Should fail when accesing two behind FirstVaild because LastValid is 1000 after", function () {
+		it.only("Should fail when accesing two behind FirstVaild because LastValid is 1000 after", function () {
 			stack.push(BigInt(TXN_OBJ.fv - 2));
 			const op = new Block(["BlkTimestamp"], 1, interpreter);
 			assert.throws(() => op.execute(stack));

From 1cdba96e0faad7003c49f00e12cd41ffe07c567e Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Thu, 27 Oct 2022 19:12:06 +0200
Subject: [PATCH 05/24] Add block to runtime; test scenario; block opcode

---
 packages/runtime/package.json                 |  2 +
 .../runtime/src/interpreter/interpreter.ts    | 13 +++--
 .../runtime/src/interpreter/opcode-list.ts    | 14 ++++--
 packages/runtime/src/runtime.ts               | 34 +++++++++++---
 .../test/src/interpreter/opcode-list.ts       | 47 +++++++++++++++----
 yarn.lock                                     | 16 +++++++
 6 files changed, 101 insertions(+), 25 deletions(-)

diff --git a/packages/runtime/package.json b/packages/runtime/package.json
index 5abaf4078..bc2d49dab 100644
--- a/packages/runtime/package.json
+++ b/packages/runtime/package.json
@@ -34,9 +34,11 @@
 	"dependencies": {
 		"@algo-builder/web": "workspace:*",
 		"@nodelib/fs.walk": "^1.2.8",
+		"@types/crypto-js": "^4.1.1",
 		"@types/json-bigint": "^1.0.1",
 		"algosdk": "^1.19.0",
 		"chalk": "^4.1.2",
+		"crypto-js": "^4.1.1",
 		"debug": "^4.3.4",
 		"elliptic": "^6.5.4",
 		"hi-base32": "^0.5.1",
diff --git a/packages/runtime/src/interpreter/interpreter.ts b/packages/runtime/src/interpreter/interpreter.ts
index a53b72aea..7ddca8334 100644
--- a/packages/runtime/src/interpreter/interpreter.ts
+++ b/packages/runtime/src/interpreter/interpreter.ts
@@ -171,7 +171,7 @@ export class Interpreter {
 
 		if (
 			txAccounts?.find((buff) => compareArray(Uint8Array.from(buff), accountPk)) !==
-				undefined ||
+			undefined ||
 			compareArray(accountPk, Uint8Array.from(this.runtime.ctx.tx.snd)) ||
 			// since tealv5, currentApplicationAddress is also allowed (directly)
 			compareArray(accountPk, decodeAddress(getApplicationAddress(appID)).publicKey) ||
@@ -597,21 +597,26 @@ export class Interpreter {
 		return result;
 	}
 
-	//TODO:add description
+	/**
+	 * This functions checks if the requested round is avaiable to access. If it is
+	 * not throws an Error
+	 * @param round: round number
+	 * @returns void
+	 */
 	assertRoundIsAvailable(round: number): void {
 		let firstAvail = this.runtime.ctx.tx.lv - MaxTxnLife - 1;
 		if (firstAvail > this.runtime.ctx.tx.lv || firstAvail === 0) {
 			// early in chain's life
 			firstAvail = 1;
 		}
-		//TODO: what happends if FirstValid is undefined?
 		let lastAvail = this.runtime.ctx.tx.fv === undefined ? 0 : this.runtime.ctx.tx.fv - 1;
 		if (this.runtime.ctx.tx.fv === undefined || lastAvail > this.runtime.ctx.tx.fv) {
 			// txn had a 0 in FirstValid
 			lastAvail = 0; // So nothing will be available
 		}
 		if (firstAvail > round || round > lastAvail) {
-			throw new Error();
+			throw new Error("round is not available");
+			//todo: add better error
 			// throw error ("round %d is not available. It's outside [%d-%d]", r, firstAvail, lastAvail)
 		}
 	}
diff --git a/packages/runtime/src/interpreter/opcode-list.ts b/packages/runtime/src/interpreter/opcode-list.ts
index 3263c133a..98fb3cb81 100644
--- a/packages/runtime/src/interpreter/opcode-list.ts
+++ b/packages/runtime/src/interpreter/opcode-list.ts
@@ -5286,15 +5286,20 @@ export class Bn254Pairing extends Op {
 		return this.computeCost();
 	}
 }
-//TODO:add description
+
+/**
+ * Opcode: 0xd1 {uint8 block field}
+ * Stack: ..., A: uint64 → ..., any
+ * field F of block A. Fail unless A falls between txn.LastValid-1002 and txn.FirstValid (exclusive)
+*/
 export class Block extends Op {
 	readonly line: number;
 	readonly field: string;
 	readonly interpreter: Interpreter;
-	//TODO:add description
 	/**
-	 * @param args
+	 * @param args Expected arguments: [BlkSeed || BlkTimestamp]
 	 * @param line line number in TEAL file
+	 * @param interpreter interpreter instance
 	 */
 	constructor(args: string[], line: number, interpreter: Interpreter) {
 		super();
@@ -5303,8 +5308,7 @@ export class Block extends Op {
 		if (argument === "BlkSeed" || argument === "BlkTimestamp") {
 			this.field = argument;
 		} else {
-			throw new Error();
-			//throw an error, unknown field
+			throw new Error("Unknown Block field");
 		}
 		this.line = line;
 		this.interpreter = interpreter;
diff --git a/packages/runtime/src/runtime.ts b/packages/runtime/src/runtime.ts
index ac4dbc579..e672ba313 100644
--- a/packages/runtime/src/runtime.ts
+++ b/packages/runtime/src/runtime.ts
@@ -7,9 +7,11 @@ import algosdk, {
 	SignedTransaction,
 	Transaction,
 } from "algosdk";
-import { randomBytes } from "crypto";
+import MD5 from "crypto-js/md5";
+// import { randomBytes } from "crypto";
 import cloneDeep from "lodash.clonedeep";
 import nacl from "tweetnacl";
+import { hash } from "tweetnacl-ts";
 import { bigint, map } from "zod";
 
 import { AccountStore, defaultSDKAccounts, RuntimeAccount } from "./account";
@@ -92,8 +94,8 @@ export class Runtime {
 
 		// context for interpreter
 		this.ctx = new Ctx(cloneDeep(this.store), <EncTx>{}, [], [], this);
-		this.round = 1;
-		this.produceBlock();
+		this.round = 258820;
+		this.populateChain(this.round);
 		this.timestamp = 1;
 	}
 
@@ -1168,26 +1170,34 @@ export class Runtime {
 		return this.executeTx(transactions);
 	}
 
+	/**
+	 * Produces new block and adds it to a Map where the keys are block numbers
+	 */
 	produceBlock() {
 		let timestamp: bigint | undefined;
 		let seed: Uint8Array | undefined;
 		if (this.store.blocks.size === 0) { //create genesis block
-			seed = randomBytes(32);
+			seed = nacl.randomBytes(32);
 			timestamp = BigInt(Math.round(new Date().getTime() / 1000));
 		} else { //add another block
 			const lastBlock = this.store.blocks.get(this.round);
 			if (lastBlock !== undefined) {
-				seed = randomBytes(32);
+				seed = new TextEncoder().encode(MD5(lastBlock.seed.toString()).toString());
 				timestamp = lastBlock.timestamp + 4n;
 				this.round += 1;// we move to new a new round
 			}
 		}
 		if (timestamp !== undefined && seed !== undefined) {
 			this.store.blocks.set(this.round, { timestamp, seed });
-		}
+		} else {
 		throw new RuntimeError(RUNTIME_ERRORS.GENERAL.PRODUCE_BLOCK); 
+		}
 	}
-
+	/**
+	 * Returns a requested Block object. If it does not exist on chain throws an error
+	 * @param round block number
+	 * @returns Block
+	 */
 	getBlock(round: number): Block {
 		const block = cloneDeep(this.store.blocks.get(round));
 		if (block !== undefined) {
@@ -1195,4 +1205,14 @@ export class Runtime {
 		}
 		throw new RuntimeError(RUNTIME_ERRORS.GENERAL.INVALID_BLOCK);
 	}
+	/**
+	 * Populates chain from first block to round number block (Produces N rounds) 
+	 * @param round current round number
+	 */
+	populateChain(round:number) {
+		this.round = 1
+		for(let blockN = 1; blockN<=round; blockN++){
+			this.produceBlock();
+		}
+	}
 }
diff --git a/packages/runtime/test/src/interpreter/opcode-list.ts b/packages/runtime/test/src/interpreter/opcode-list.ts
index 242be0085..221f902da 100644
--- a/packages/runtime/test/src/interpreter/opcode-list.ts
+++ b/packages/runtime/test/src/interpreter/opcode-list.ts
@@ -11,8 +11,10 @@ import algosdk, {
 import { assert } from "chai";
 import { ec as EC } from "elliptic";
 import { sha512_256 } from "js-sha512";
+import cloneDeep from "lodash.clonedeep";
 import { describe } from "mocha";
 import nacl from "tweetnacl";
+import { isGeneratorFunction } from "util/types";
 
 import { ExecutionMode } from "../../../build/types";
 import { AccountStore } from "../../../src/account";
@@ -7564,38 +7566,65 @@ describe("Teal Opcodes", function () {
 			assert.equal(expectedResult, stack.pop());
 		});
 	});
-	describe.only("block op", function () {
+	describe("Block opcode", function () {
 		const stack = new Stack<StackElem>();
 		let interpreter: Interpreter;
-		const LAST_VALID = 259820n;
+		const FIRST_VALID = 258820n;
 		this.beforeEach(function () {
 			interpreter = new Interpreter();
 			interpreter.runtime = new Runtime([]);
-			interpreter.runtime.ctx.tx = TXN_OBJ;
+			interpreter.runtime.ctx.tx = cloneDeep(TXN_OBJ);
 			interpreter.tealVersion = MaxTEALVersion; // set tealversion to latest (to support all tx fields)
 		});
 
-		it.only("Should fail when accesing two behind FirstVaild because LastValid is 1000 after", function () {
-			stack.push(BigInt(TXN_OBJ.fv - 2));
+		it("Should fail when accesing two behind FirstVaild because LastValid is 1000 after", function () {
+			stack.push(BigInt(FIRST_VALID - 2n));
 			const op = new Block(["BlkTimestamp"], 1, interpreter);
 			assert.throws(() => op.execute(stack));
 		});
-		it("Should allow to acces two behind FirstValid", function () {
-			stack.push(BigInt(TXN_OBJ.fv - 1));
+
+		it("Should allow to acces two behind FirstValid if LastValid is 100 after", function () {
+			interpreter.runtime.ctx.tx.lv = Number(FIRST_VALID) + 100;
+			stack.push(BigInt(FIRST_VALID - 2n));
 			const op = new Block(["BlkTimestamp"], 1, interpreter);
 			assert.doesNotThrow(() => op.execute(stack));
 		});
+
 		it("Should return two different seeds for to different rounds", function () {
+			interpreter.runtime.ctx.tx.lv = Number(FIRST_VALID) + 100;
 			const op = new Block(["BlkTimestamp"], 1, interpreter);
 			//first round
-			stack.push(LAST_VALID - 2n);
+			stack.push(FIRST_VALID - 1n);
 			op.execute(stack);
 			const seedRound1 = stack.pop();
 			//second round
-			stack.push(LAST_VALID - 3n);
+			stack.push(FIRST_VALID - 2n);
 			op.execute(stack);
 			const seedRound2 = stack.pop();
 			assert.notEqual(seedRound1, seedRound2);
 		});
+
+		it("Should fail when accesing block 0 even if last valid is low", function(){
+			interpreter.runtime.ctx.tx.lv = 100;
+			interpreter.runtime.ctx.tx.fv = 5;
+			stack.push(0n);
+			const op = new Block(["BlkTimestamp"], 1, interpreter);
+			assert.throws(() => op.execute(stack));
+		});
+
+		it("Should return seed for a block that is within boundries and exist", function(){
+			stack.push(FIRST_VALID - 1n);
+			const op = new Block(["BlkSeed"], 1, interpreter);
+			op.execute(stack);
+			const result = stack.pop();
+			assert.equal((result as Buffer).length, 32);
+		});
+
+		it("Should return correct cost", function(){
+			stack.push(FIRST_VALID - 1n);
+			const op = new Block(["BlkSeed"], 1, interpreter);
+			const cost = op.execute(stack);
+			assert.equal(cost, 1);
+		});
 	});
 });
diff --git a/yarn.lock b/yarn.lock
index 0b90af6fd..0399e6890 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -63,6 +63,7 @@ __metadata:
     "@algo-builder/web": "workspace:*"
     "@nodelib/fs.walk": ^1.2.8
     "@types/chai": ^4.3.0
+    "@types/crypto-js": ^4.1.1
     "@types/debug": ^4.1.7
     "@types/elliptic": ^6.4.14
     "@types/json-bigint": ^1.0.1
@@ -73,6 +74,7 @@ __metadata:
     algosdk: ^1.19.0
     chai: ^4.3.6
     chalk: ^4.1.2
+    crypto-js: ^4.1.1
     debug: ^4.3.4
     elliptic: ^6.5.4
     eslint: ^8.10.0
@@ -668,6 +670,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/crypto-js@npm:^4.1.1":
+  version: 4.1.1
+  resolution: "@types/crypto-js@npm:4.1.1"
+  checksum: ea3d6a67b69f88baeb6af96004395903d2367a41bd5cd86306da23a44dd96589749495da50974a9b01bb5163c500764c8a33706831eade036bddae016417e3ea
+  languageName: node
+  linkType: hard
+
 "@types/debug@npm:^4.1.7":
   version: 4.1.7
   resolution: "@types/debug@npm:4.1.7"
@@ -2152,6 +2161,13 @@ __metadata:
   languageName: unknown
   linkType: soft
 
+"crypto-js@npm:^4.1.1":
+  version: 4.1.1
+  resolution: "crypto-js@npm:4.1.1"
+  checksum: b3747c12ee3a7632fab3b3e171ea50f78b182545f0714f6d3e7e2858385f0f4101a15f2517e033802ce9d12ba50a391575ff4638c9de3dd9b2c4bc47768d5425
+  languageName: node
+  linkType: hard
+
 "dao@workspace:examples/dao":
   version: 0.0.0-use.local
   resolution: "dao@workspace:examples/dao"

From 3fca2975d664b23df791718b54f6cb391c846f05 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Thu, 27 Oct 2022 23:50:50 +0200
Subject: [PATCH 06/24] change defult value of round to 2000

---
 packages/runtime/src/runtime.ts                      | 5 +----
 packages/runtime/test/mocks/txn.ts                   | 4 ++--
 packages/runtime/test/src/interpreter/opcode-list.ts | 2 +-
 3 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/packages/runtime/src/runtime.ts b/packages/runtime/src/runtime.ts
index e672ba313..e9af9430d 100644
--- a/packages/runtime/src/runtime.ts
+++ b/packages/runtime/src/runtime.ts
@@ -11,8 +11,6 @@ import MD5 from "crypto-js/md5";
 // import { randomBytes } from "crypto";
 import cloneDeep from "lodash.clonedeep";
 import nacl from "tweetnacl";
-import { hash } from "tweetnacl-ts";
-import { bigint, map } from "zod";
 
 import { AccountStore, defaultSDKAccounts, RuntimeAccount } from "./account";
 import { Ctx } from "./ctx";
@@ -23,7 +21,6 @@ import { compareArray } from "./lib/compare";
 import {
 	ALGORAND_ACCOUNT_MIN_BALANCE,
 	ALGORAND_MAX_TX_ARRAY_LEN,
-	BlockFinalizationTime,
 	MAX_APP_PROGRAM_COST,
 	TransactionTypeEnum,
 	ZERO_ADDRESS_STR,
@@ -94,7 +91,7 @@ export class Runtime {
 
 		// context for interpreter
 		this.ctx = new Ctx(cloneDeep(this.store), <EncTx>{}, [], [], this);
-		this.round = 258820;
+		this.round = 2000;
 		this.populateChain(this.round);
 		this.timestamp = 1;
 	}
diff --git a/packages/runtime/test/mocks/txn.ts b/packages/runtime/test/mocks/txn.ts
index 923c5160d..ff0325791 100644
--- a/packages/runtime/test/mocks/txn.ts
+++ b/packages/runtime/test/mocks/txn.ts
@@ -22,8 +22,8 @@ const txn_obj = {
 	fee: 1000,
 	amt: 20200,
 	aamt: 100,
-	fv: 258820,
-	lv: 259820,
+	fv: 2000,
+	lv: 3000,
 	note: Buffer.from("Note"),
 	gen: "default-v1",
 	gh: Buffer.from("default-v1"),
diff --git a/packages/runtime/test/src/interpreter/opcode-list.ts b/packages/runtime/test/src/interpreter/opcode-list.ts
index 221f902da..f13d89a67 100644
--- a/packages/runtime/test/src/interpreter/opcode-list.ts
+++ b/packages/runtime/test/src/interpreter/opcode-list.ts
@@ -7569,7 +7569,7 @@ describe("Teal Opcodes", function () {
 	describe("Block opcode", function () {
 		const stack = new Stack<StackElem>();
 		let interpreter: Interpreter;
-		const FIRST_VALID = 258820n;
+		const FIRST_VALID = 2000n;
 		this.beforeEach(function () {
 			interpreter = new Interpreter();
 			interpreter.runtime = new Runtime([]);

From dc2045653d4b4daf15e5429b4f102ac0f4f35a41 Mon Sep 17 00:00:00 2001
From: sczembor <43810037+sczembor@users.noreply.github.com>
Date: Fri, 28 Oct 2022 00:12:24 +0200
Subject: [PATCH 07/24] change finalisation time

---
 packages/runtime/src/lib/constants.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/runtime/src/lib/constants.ts b/packages/runtime/src/lib/constants.ts
index 600687404..2f29920ac 100644
--- a/packages/runtime/src/lib/constants.ts
+++ b/packages/runtime/src/lib/constants.ts
@@ -56,8 +56,8 @@ export const MAX_LOCAL_SCHEMA_ENTRIES = 16;
 export const MAX_INPUT_BYTE_LEN = 64;
 export const MAX_OUTPUT_BYTE_LEN = 128;
 
-export const MaxTxnLife = 1000; //TODO:add description
-export const BlockFinalizationTime = 2n; // block finalization time in seconds truncated down
+export const MaxTxnLife = 1000;
+export const BlockFinalisationTime = 4n; // block finalisation time in seconds truncated down
 
 export const ZERO_ADDRESS = new Uint8Array(32);
 export const ZERO_ADDRESS_STR = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAY5HFKQ";

From 1c4bb9c733cbc18a7ffa6d607615c2ffd69ab621 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 00:40:54 +0200
Subject: [PATCH 08/24] add enum; add proper error

---
 packages/runtime/src/errors/errors-list.ts      | 6 ++++++
 packages/runtime/src/interpreter/opcode-list.ts | 8 ++++----
 packages/runtime/src/lib/constants.ts           | 5 +++++
 packages/runtime/src/runtime.ts                 | 4 ++--
 4 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/packages/runtime/src/errors/errors-list.ts b/packages/runtime/src/errors/errors-list.ts
index 7f205f7b3..803941a84 100644
--- a/packages/runtime/src/errors/errors-list.ts
+++ b/packages/runtime/src/errors/errors-list.ts
@@ -456,6 +456,12 @@ maximun uint128`,
 		description:
 			"Maximum program length %maxAppProgramLen% exceeded. Use `ApprovalProgramPages` instead",
 	},
+	UNKNOWN_BLOCK_FIELD: {
+		number: 1067,
+		message: "Unknown block opcode field",
+		title: "Unknown field",
+		description: "Block opcode support only BlkTimestamp and BlkSeed field, got: %field",
+	}
 };
 
 const runtimeGeneralErrors = {
diff --git a/packages/runtime/src/interpreter/opcode-list.ts b/packages/runtime/src/interpreter/opcode-list.ts
index a53b53c3b..c74fc2285 100644
--- a/packages/runtime/src/interpreter/opcode-list.ts
+++ b/packages/runtime/src/interpreter/opcode-list.ts
@@ -29,7 +29,6 @@ import {
 	ALGORAND_MAX_LOGS_LENGTH,
 	AppParamDefined,
 	AssetParamMap,
-	BlockFinalizationTime,
 	GlobalFields,
 	ITxArrFields,
 	json_refTypes,
@@ -46,6 +45,7 @@ import {
 	TransactionTypeEnum,
 	TxArrFields,
 	ZERO_ADDRESS,
+	blockFieldTypes,
 } from "../lib/constants";
 import { addInnerTransaction, calculateInnerTxCredit, setInnerTxField } from "../lib/itxn";
 import { bigintSqrt } from "../lib/math";
@@ -5304,10 +5304,10 @@ export class Block extends Op {
 		super();
 		assertLen(args.length, 1, line);
 		const argument = args[0];
-		if (argument === "BlkSeed" || argument === "BlkTimestamp") {
+		if (argument === blockFieldTypes.BlkSeed|| argument === blockFieldTypes.BlkTimestamp) {
 			this.field = argument;
 		} else {
-			throw new Error("Unknown Block field");
+			throw new RuntimeError(RUNTIME_ERRORS.TEAL.UNKNOWN_BLOCK_FIELD, {field: argument});
 		}
 		this.line = line;
 		this.interpreter = interpreter;
@@ -5318,7 +5318,7 @@ export class Block extends Op {
 		this.interpreter.assertRoundIsAvailable(round);
 		const block = this.interpreter.runtime.getBlock(round);
 		let result: StackElem;
-		if (this.field === "BlkSeed") {
+		if (this.field === blockFieldTypes.BlkSeed) {
 			result = block.seed;
 		} else {
 			//"BlkTimestamp"
diff --git a/packages/runtime/src/lib/constants.ts b/packages/runtime/src/lib/constants.ts
index 2f29920ac..43e22d39f 100644
--- a/packages/runtime/src/lib/constants.ts
+++ b/packages/runtime/src/lib/constants.ts
@@ -520,6 +520,11 @@ export const json_refTypes = {
 	JSONObject: "JSONObject",
 };
 
+export enum blockFieldTypes {
+	BlkTimestamp = "BlkTimestamp",
+	BlkSeed = "BlkSeed",
+};
+
 export enum TxFieldEnum {
 	FirstValidTime = "FirstValidTime",
 	TypeEnum = "TypeEnum",
diff --git a/packages/runtime/src/runtime.ts b/packages/runtime/src/runtime.ts
index fb130a758..7bbd4c056 100644
--- a/packages/runtime/src/runtime.ts
+++ b/packages/runtime/src/runtime.ts
@@ -7,7 +7,6 @@ import algosdk, {
 	SignedTransaction,
 	Transaction,
 } from "algosdk";
-
 import MD5 from "crypto-js/md5";
 import cloneDeep from "lodash.clonedeep";
 import nacl from "tweetnacl";
@@ -21,6 +20,7 @@ import { compareArray } from "./lib/compare";
 import {
 	ALGORAND_ACCOUNT_MIN_BALANCE,
 	ALGORAND_MAX_TX_ARRAY_LEN,
+	BlockFinalisationTime,
 	MAX_APP_PROGRAM_COST,
 	TransactionTypeEnum,
 	ZERO_ADDRESS_STR,
@@ -1180,7 +1180,7 @@ export class Runtime {
 			const lastBlock = this.store.blocks.get(this.round);
 			if (lastBlock !== undefined) {
 				seed = new TextEncoder().encode(MD5(lastBlock.seed.toString()).toString());
-				timestamp = lastBlock.timestamp + 4n;
+				timestamp = lastBlock.timestamp + BlockFinalisationTime;
 				this.round += 1;// we move to new a new round
 			}
 		}

From 4537e8723108f5886cab12a4965f69c803ded73a Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 01:41:10 +0200
Subject: [PATCH 09/24] add tests for runtime functions

---
 packages/runtime/src/runtime.ts      |  2 +-
 packages/runtime/test/src/runtime.ts | 30 +++++++++++++++++++++++++---
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/packages/runtime/src/runtime.ts b/packages/runtime/src/runtime.ts
index 7bbd4c056..2d6574f31 100644
--- a/packages/runtime/src/runtime.ts
+++ b/packages/runtime/src/runtime.ts
@@ -1206,7 +1206,7 @@ export class Runtime {
 	 * Populates chain from first block to round number block (Produces N rounds) 
 	 * @param round current round number
 	 */
-	populateChain(round:number) {
+	private populateChain(round:number) {
 		this.round = 1
 		for(let blockN = 1; blockN<=round; blockN++){
 			this.produceBlock();
diff --git a/packages/runtime/test/src/runtime.ts b/packages/runtime/test/src/runtime.ts
index 9d53d8f7b..d9ca7d990 100644
--- a/packages/runtime/test/src/runtime.ts
+++ b/packages/runtime/test/src/runtime.ts
@@ -1,13 +1,12 @@
 import { types } from "@algo-builder/web";
-import { ExecParams, SignType, TransactionType } from "@algo-builder/web/build/types";
 import algosdk, { LogicSigAccount, Transaction } from "algosdk";
-import { assert } from "chai";
+import { assert, expect } from "chai";
 import sinon from "sinon";
 
 import { getProgram } from "../../src";
 import { AccountStore } from "../../src/account";
 import { RUNTIME_ERRORS } from "../../src/errors/errors-list";
-import { ASSET_CREATION_FEE } from "../../src/lib/constants";
+import { ASSET_CREATION_FEE, BlockFinalisationTime } from "../../src/lib/constants";
 import { mockSuggestedParams } from "../../src/mock/tx";
 import { Runtime } from "../../src/runtime";
 import { AccountStoreI } from "../../src/types";
@@ -1442,3 +1441,28 @@ describe("Helper functions", function () {
 		});
 	});
 });
+describe.only("Funtions related to runtime chain", function(){
+	let runtime: Runtime;
+
+	this.beforeEach(function(){
+		runtime = new Runtime([]);
+	})
+
+	it("Should return current block", function(){
+		const currentBlock = runtime.getBlock(runtime.getRound());
+		assert.equal(currentBlock.seed.length, 32);
+		expect(currentBlock.timestamp).to.be.a('bigint');
+	})
+
+	it("Should produce a new block and move to next round", function(){
+		const currentRound = runtime.getRound();
+		const currentBlock = runtime.getBlock(currentRound);
+		//produce new block and move to next round
+		runtime.produceBlock();
+		const newRound = runtime.getRound();
+		const newBlock = runtime.getBlock(newRound);
+		assert.equal(currentRound + 1, newRound);
+		assert.notDeepEqual(currentBlock, newBlock);
+		assert.equal(currentBlock.timestamp + BlockFinalisationTime, newBlock.timestamp)
+	})
+})

From 27820e30444690a7fd94250a1bae5a79cc1d9069 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 01:45:32 +0200
Subject: [PATCH 10/24] add tests for runtime functions

---
 packages/runtime/test/src/runtime.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/runtime/test/src/runtime.ts b/packages/runtime/test/src/runtime.ts
index d9ca7d990..1dbf577c3 100644
--- a/packages/runtime/test/src/runtime.ts
+++ b/packages/runtime/test/src/runtime.ts
@@ -1454,7 +1454,7 @@ describe.only("Funtions related to runtime chain", function(){
 		expect(currentBlock.timestamp).to.be.a('bigint');
 	})
 
-	it("Should produce a new block and move to next round", function(){
+	it.only("Should produce a new block and move to next round", function(){
 		const currentRound = runtime.getRound();
 		const currentBlock = runtime.getBlock(currentRound);
 		//produce new block and move to next round

From 1c33971803b16bb49468f3fe1121bc01cf1df0a8 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 01:46:14 +0200
Subject: [PATCH 11/24] add tests for runtime functions

---
 packages/runtime/test/src/runtime.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/runtime/test/src/runtime.ts b/packages/runtime/test/src/runtime.ts
index 1dbf577c3..d9ca7d990 100644
--- a/packages/runtime/test/src/runtime.ts
+++ b/packages/runtime/test/src/runtime.ts
@@ -1454,7 +1454,7 @@ describe.only("Funtions related to runtime chain", function(){
 		expect(currentBlock.timestamp).to.be.a('bigint');
 	})
 
-	it.only("Should produce a new block and move to next round", function(){
+	it("Should produce a new block and move to next round", function(){
 		const currentRound = runtime.getRound();
 		const currentBlock = runtime.getBlock(currentRound);
 		//produce new block and move to next round

From c8c5c0bf6860599a225661331050e2812e0d265f Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 01:47:57 +0200
Subject: [PATCH 12/24] add tests for runtime functions

---
 .husky/_/dissalowed_words.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.husky/_/dissalowed_words.sh b/.husky/_/dissalowed_words.sh
index 00162ccfa..72328885d 100755
--- a/.husky/_/dissalowed_words.sh
+++ b/.husky/_/dissalowed_words.sh
@@ -15,3 +15,4 @@ do
     done
 done
 exit $status
+exit 1

From b46f074e32d6f3b2ced30ed86dd481b418fa2880 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 01:48:39 +0200
Subject: [PATCH 13/24] add tests for runtime functions

---
 .husky/_/dissalowed_words.sh         | 1 -
 packages/runtime/test/src/runtime.ts | 2 +-
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/.husky/_/dissalowed_words.sh b/.husky/_/dissalowed_words.sh
index 72328885d..00162ccfa 100755
--- a/.husky/_/dissalowed_words.sh
+++ b/.husky/_/dissalowed_words.sh
@@ -15,4 +15,3 @@ do
     done
 done
 exit $status
-exit 1
diff --git a/packages/runtime/test/src/runtime.ts b/packages/runtime/test/src/runtime.ts
index d9ca7d990..1dbf577c3 100644
--- a/packages/runtime/test/src/runtime.ts
+++ b/packages/runtime/test/src/runtime.ts
@@ -1454,7 +1454,7 @@ describe.only("Funtions related to runtime chain", function(){
 		expect(currentBlock.timestamp).to.be.a('bigint');
 	})
 
-	it("Should produce a new block and move to next round", function(){
+	it.only("Should produce a new block and move to next round", function(){
 		const currentRound = runtime.getRound();
 		const currentBlock = runtime.getBlock(currentRound);
 		//produce new block and move to next round

From 03409df96a332e81d7c3b32f4975eada334fbeef Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 02:09:24 +0200
Subject: [PATCH 14/24] test

---
 .husky/pre-commit                    |  1 +
 packages/runtime/test/src/runtime.ts | 20 ++++++++++----------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/.husky/pre-commit b/.husky/pre-commit
index b15fa986d..091a73a76 100755
--- a/.husky/pre-commit
+++ b/.husky/pre-commit
@@ -3,3 +3,4 @@
 . "$(dirname "$0")/_/dissalowed_words.sh"
 
 yarn run lint-staged
+
diff --git a/packages/runtime/test/src/runtime.ts b/packages/runtime/test/src/runtime.ts
index 1dbf577c3..b7dfb90cb 100644
--- a/packages/runtime/test/src/runtime.ts
+++ b/packages/runtime/test/src/runtime.ts
@@ -1441,20 +1441,20 @@ describe("Helper functions", function () {
 		});
 	});
 });
-describe.only("Funtions related to runtime chain", function(){
+describe("Funtions related to runtime chain", function () {
 	let runtime: Runtime;
 
-	this.beforeEach(function(){
+	this.beforeEach(function () {
 		runtime = new Runtime([]);
-	})
+	});
 
-	it("Should return current block", function(){
+	it.only("Should return current block", function () {
 		const currentBlock = runtime.getBlock(runtime.getRound());
 		assert.equal(currentBlock.seed.length, 32);
-		expect(currentBlock.timestamp).to.be.a('bigint');
-	})
+		expect(currentBlock.timestamp).to.be.a("bigint");
+	});
 
-	it.only("Should produce a new block and move to next round", function(){
+	it("Should produce a new block and move to next round", function () {
 		const currentRound = runtime.getRound();
 		const currentBlock = runtime.getBlock(currentRound);
 		//produce new block and move to next round
@@ -1463,6 +1463,6 @@ describe.only("Funtions related to runtime chain", function(){
 		const newBlock = runtime.getBlock(newRound);
 		assert.equal(currentRound + 1, newRound);
 		assert.notDeepEqual(currentBlock, newBlock);
-		assert.equal(currentBlock.timestamp + BlockFinalisationTime, newBlock.timestamp)
-	})
-})
+		assert.equal(currentBlock.timestamp + BlockFinalisationTime, newBlock.timestamp);
+	});
+});

From fca66c61cd053cfaf10e4946bb597c11ecb8b351 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 02:10:45 +0200
Subject: [PATCH 15/24] test

---
 packages/runtime/test/src/runtime.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/runtime/test/src/runtime.ts b/packages/runtime/test/src/runtime.ts
index b7dfb90cb..b22279a55 100644
--- a/packages/runtime/test/src/runtime.ts
+++ b/packages/runtime/test/src/runtime.ts
@@ -1448,7 +1448,7 @@ describe("Funtions related to runtime chain", function () {
 		runtime = new Runtime([]);
 	});
 
-	it.only("Should return current block", function () {
+	it("Should return current block", function () {
 		const currentBlock = runtime.getBlock(runtime.getRound());
 		assert.equal(currentBlock.seed.length, 32);
 		expect(currentBlock.timestamp).to.be.a("bigint");

From 40a4c310a5568cf91a256c3adbdcb65bd8546c6c Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 02:11:48 +0200
Subject: [PATCH 16/24] test

---
 .husky/pre-commit | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.husky/pre-commit b/.husky/pre-commit
index 091a73a76..803725380 100755
--- a/.husky/pre-commit
+++ b/.husky/pre-commit
@@ -1,4 +1,5 @@
 #!/bin/sh
+echo "test"
 . "$(dirname "$0")/_/husky.sh"
 . "$(dirname "$0")/_/dissalowed_words.sh"
 

From 63054b0987983c09658972fd159a2d50d0049868 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 02:15:05 +0200
Subject: [PATCH 17/24] test

---
 .husky/pre-commit                    | 1 -
 packages/runtime/test/src/runtime.ts | 2 +-
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/.husky/pre-commit b/.husky/pre-commit
index 803725380..091a73a76 100755
--- a/.husky/pre-commit
+++ b/.husky/pre-commit
@@ -1,5 +1,4 @@
 #!/bin/sh
-echo "test"
 . "$(dirname "$0")/_/husky.sh"
 . "$(dirname "$0")/_/dissalowed_words.sh"
 
diff --git a/packages/runtime/test/src/runtime.ts b/packages/runtime/test/src/runtime.ts
index b22279a55..dcceb98e4 100644
--- a/packages/runtime/test/src/runtime.ts
+++ b/packages/runtime/test/src/runtime.ts
@@ -1441,7 +1441,7 @@ describe("Helper functions", function () {
 		});
 	});
 });
-describe("Funtions related to runtime chain", function () {
+describe.only("Funtions related to runtime chain", function () {
 	let runtime: Runtime;
 
 	this.beforeEach(function () {

From 5aa5ffae965b190a64b591cf5891deffa7277c27 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 02:18:29 +0200
Subject: [PATCH 18/24] remove .only from tests

---
 packages/runtime/test/src/runtime.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/runtime/test/src/runtime.ts b/packages/runtime/test/src/runtime.ts
index dcceb98e4..b22279a55 100644
--- a/packages/runtime/test/src/runtime.ts
+++ b/packages/runtime/test/src/runtime.ts
@@ -1441,7 +1441,7 @@ describe("Helper functions", function () {
 		});
 	});
 });
-describe.only("Funtions related to runtime chain", function () {
+describe("Funtions related to runtime chain", function () {
 	let runtime: Runtime;
 
 	this.beforeEach(function () {

From 0d32529594f5713ccf679d68bc2c7d10b0920853 Mon Sep 17 00:00:00 2001
From: Stanislaw Czembor <stanislaw.czembor@gmail.com>
Date: Fri, 28 Oct 2022 04:03:58 +0200
Subject: [PATCH 19/24] add block opcode to parser

---
 packages/runtime/src/parser/parser.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/packages/runtime/src/parser/parser.ts b/packages/runtime/src/parser/parser.ts
index fdce32b91..00e93d141 100644
--- a/packages/runtime/src/parser/parser.ts
+++ b/packages/runtime/src/parser/parser.ts
@@ -156,6 +156,7 @@ import {
 	Txna,
 	Txnas,
 	Uncover,
+	Block,
 } from "../interpreter/opcode-list";
 import {
 	LOGIC_SIG_MAX_COST,
@@ -409,6 +410,7 @@ opCodeMap[7] = {
 	sha3_256: Sha3_256,
 	ed25519verify_bare: Ed25519verify_bare,
 	json_ref: Json_ref,
+	block: Block,
 };
 /**
  * TEALv8
@@ -486,6 +488,7 @@ const interpreterReqList = new Set([
 	"keccak256",
 	"sha3_256",
 	"ed25519verify",
+	"block",
 ]);
 
 const signatureModeOps = new Set(["arg", "args", "arg_0", "arg_1", "arg_2", "arg_3"]);

From af3d55d0570f895418b7d9b25bd634f8e13d7909 Mon Sep 17 00:00:00 2001
From: sczembor <43810037+sczembor@users.noreply.github.com>
Date: Wed, 2 Nov 2022 13:05:40 +0100
Subject: [PATCH 20/24] Apply suggestions from code review

Co-authored-by: Ravindra Meena <rmeena840@gmail.com>
---
 packages/runtime/src/interpreter/opcode-list.ts | 3 ++-
 packages/runtime/src/runtime.ts                 | 6 +++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/packages/runtime/src/interpreter/opcode-list.ts b/packages/runtime/src/interpreter/opcode-list.ts
index c74fc2285..5b5cb3730 100644
--- a/packages/runtime/src/interpreter/opcode-list.ts
+++ b/packages/runtime/src/interpreter/opcode-list.ts
@@ -5312,6 +5312,7 @@ export class Block extends Op {
 		this.line = line;
 		this.interpreter = interpreter;
 	}
+	
 	execute(stack: TEALStack): number {
 		this.assertMinStackLen(stack, 1, this.line);
 		const round = Number(this.assertBigInt(stack.pop(), this.line));
@@ -5322,7 +5323,7 @@ export class Block extends Op {
 			result = block.seed;
 		} else {
 			//"BlkTimestamp"
-			//seconds since epoch - rounds, assuming one round(block) = 2.5s truncated to 2s (BigInt)
+			//seconds since epoch - rounds, assuming one round(block) = 4.5s truncated to 4s (BigInt)
 			result = block.timestamp;
 		}
 		stack.push(result);
diff --git a/packages/runtime/src/runtime.ts b/packages/runtime/src/runtime.ts
index 2d6574f31..785428b5c 100644
--- a/packages/runtime/src/runtime.ts
+++ b/packages/runtime/src/runtime.ts
@@ -1178,13 +1178,13 @@ export class Runtime {
 			timestamp = BigInt(Math.round(new Date().getTime() / 1000));
 		} else { //add another block
 			const lastBlock = this.store.blocks.get(this.round);
-			if (lastBlock !== undefined) {
+			if (lastBlock) {
 				seed = new TextEncoder().encode(MD5(lastBlock.seed.toString()).toString());
 				timestamp = lastBlock.timestamp + BlockFinalisationTime;
 				this.round += 1;// we move to new a new round
 			}
 		}
-		if (timestamp !== undefined && seed !== undefined) {
+		if (timestamp && seed) {
 			this.store.blocks.set(this.round, { timestamp, seed });
 		} else {
 		throw new RuntimeError(RUNTIME_ERRORS.GENERAL.PRODUCE_BLOCK); 
@@ -1197,7 +1197,7 @@ export class Runtime {
 	 */
 	getBlock(round: number): Block {
 		const block = cloneDeep(this.store.blocks.get(round));
-		if (block !== undefined) {
+		if (block) {
 			return block;
 		}
 		throw new RuntimeError(RUNTIME_ERRORS.GENERAL.INVALID_BLOCK);

From 7f6bc74eb3654d8da3de535fa30153da6085a1f4 Mon Sep 17 00:00:00 2001
From: sczembor <43810037+sczembor@users.noreply.github.com>
Date: Wed, 2 Nov 2022 13:15:46 +0100
Subject: [PATCH 21/24] code review suggestions

---
 packages/runtime/src/interpreter/opcode-list.ts     | 10 ++--------
 .../runtime/test/src/interpreter/opcode-list.ts     | 13 +++++++------
 2 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/packages/runtime/src/interpreter/opcode-list.ts b/packages/runtime/src/interpreter/opcode-list.ts
index 5b5cb3730..0bc95edee 100644
--- a/packages/runtime/src/interpreter/opcode-list.ts
+++ b/packages/runtime/src/interpreter/opcode-list.ts
@@ -5318,14 +5318,8 @@ export class Block extends Op {
 		const round = Number(this.assertBigInt(stack.pop(), this.line));
 		this.interpreter.assertRoundIsAvailable(round);
 		const block = this.interpreter.runtime.getBlock(round);
-		let result: StackElem;
-		if (this.field === blockFieldTypes.BlkSeed) {
-			result = block.seed;
-		} else {
-			//"BlkTimestamp"
-			//seconds since epoch - rounds, assuming one round(block) = 4.5s truncated to 4s (BigInt)
-			result = block.timestamp;
-		}
+		//"BlkTimestamp" = seconds since epoch, assuming one round(block) = 4.5s truncated to 4s (BigInt)
+		const result = (this.field === blockFieldTypes.BlkSeed) ? block.seed : block.timestamp
 		stack.push(result);
 		return this.computeCost();
 	}
diff --git a/packages/runtime/test/src/interpreter/opcode-list.ts b/packages/runtime/test/src/interpreter/opcode-list.ts
index f13d89a67..7502bddbd 100644
--- a/packages/runtime/test/src/interpreter/opcode-list.ts
+++ b/packages/runtime/test/src/interpreter/opcode-list.ts
@@ -175,6 +175,7 @@ import {
 	MaxTEALVersion,
 	MIN_UINT8,
 	ZERO_ADDRESS,
+	blockFieldTypes,
 } from "../../../src/lib/constants";
 import {
 	bigEndianBytesToBigInt,
@@ -7579,20 +7580,20 @@ describe("Teal Opcodes", function () {
 
 		it("Should fail when accesing two behind FirstVaild because LastValid is 1000 after", function () {
 			stack.push(BigInt(FIRST_VALID - 2n));
-			const op = new Block(["BlkTimestamp"], 1, interpreter);
+			const op = new Block([blockFieldTypes.BlkTimestamp], 1, interpreter);
 			assert.throws(() => op.execute(stack));
 		});
 
 		it("Should allow to acces two behind FirstValid if LastValid is 100 after", function () {
 			interpreter.runtime.ctx.tx.lv = Number(FIRST_VALID) + 100;
 			stack.push(BigInt(FIRST_VALID - 2n));
-			const op = new Block(["BlkTimestamp"], 1, interpreter);
+			const op = new Block([blockFieldTypes.BlkTimestamp], 1, interpreter);
 			assert.doesNotThrow(() => op.execute(stack));
 		});
 
 		it("Should return two different seeds for to different rounds", function () {
 			interpreter.runtime.ctx.tx.lv = Number(FIRST_VALID) + 100;
-			const op = new Block(["BlkTimestamp"], 1, interpreter);
+			const op = new Block([blockFieldTypes.BlkSeed], 1, interpreter);
 			//first round
 			stack.push(FIRST_VALID - 1n);
 			op.execute(stack);
@@ -7608,13 +7609,13 @@ describe("Teal Opcodes", function () {
 			interpreter.runtime.ctx.tx.lv = 100;
 			interpreter.runtime.ctx.tx.fv = 5;
 			stack.push(0n);
-			const op = new Block(["BlkTimestamp"], 1, interpreter);
+			const op = new Block([blockFieldTypes.BlkTimestamp], 1, interpreter);
 			assert.throws(() => op.execute(stack));
 		});
 
 		it("Should return seed for a block that is within boundries and exist", function(){
 			stack.push(FIRST_VALID - 1n);
-			const op = new Block(["BlkSeed"], 1, interpreter);
+			const op = new Block([blockFieldTypes.BlkSeed], 1, interpreter);
 			op.execute(stack);
 			const result = stack.pop();
 			assert.equal((result as Buffer).length, 32);
@@ -7622,7 +7623,7 @@ describe("Teal Opcodes", function () {
 
 		it("Should return correct cost", function(){
 			stack.push(FIRST_VALID - 1n);
-			const op = new Block(["BlkSeed"], 1, interpreter);
+			const op = new Block([blockFieldTypes.BlkSeed], 1, interpreter);
 			const cost = op.execute(stack);
 			assert.equal(cost, 1);
 		});

From c8b433b255c6470fe0ea929711f5d715c7e55c03 Mon Sep 17 00:00:00 2001
From: sczembor <43810037+sczembor@users.noreply.github.com>
Date: Wed, 2 Nov 2022 20:58:46 +0100
Subject: [PATCH 22/24] declare strings and fixed integer values as const

---
 packages/runtime/src/interpreter/opcode-list.ts | 15 +++++++++------
 packages/runtime/src/lib/constants.ts           | 10 ++++++++++
 packages/runtime/src/runtime.ts                 |  6 +++---
 .../runtime/test/src/interpreter/opcode-list.ts | 17 +++++++++--------
 4 files changed, 31 insertions(+), 17 deletions(-)

diff --git a/packages/runtime/src/interpreter/opcode-list.ts b/packages/runtime/src/interpreter/opcode-list.ts
index c47b935a3..2ee29aaa8 100644
--- a/packages/runtime/src/interpreter/opcode-list.ts
+++ b/packages/runtime/src/interpreter/opcode-list.ts
@@ -43,8 +43,11 @@ import {
 	MAX_UINT128,
 	MaxTEALVersion,
 	OpGasCost,
+	proofLength,
+	publicKeyLength,
 	TransactionTypeEnum,
 	TxArrFields,
+	vrfVerifyFieldTypes,
 	ZERO_ADDRESS,
 } from "../lib/constants";
 import { addInnerTransaction, calculateInnerTxCredit, setInnerTxField } from "../lib/itxn";
@@ -5344,11 +5347,11 @@ export class VrfVerify extends Op {
 		super();
 		this.line = line;
 		switch (argument) {
-			case "VrfAlgorand": {
+			case vrfVerifyFieldTypes.VrfAlgorand: {
 				this.vrfType = argument;
 				break;
 			}
-			case "VrfStandard": {
+			case vrfVerifyFieldTypes.VrfStandard: {
 				this.vrfType = argument;
 				break;
 			}
@@ -5359,7 +5362,7 @@ export class VrfVerify extends Op {
 	}
 
 	computeCost(): number {
-		return 5700;
+		return OpGasCost[7]["vrf_verify"];
 	}
 
 	execute(stack: TEALStack): number {
@@ -5368,13 +5371,13 @@ export class VrfVerify extends Op {
 		const proof = this.assertBytes(stack.pop(), this.line);
 		const publicKey = this.assertBytes(stack.pop(), this.line);
 
-		if (proof.length !== 80) {
+		if (proof.length !== proofLength) {
 			throw new RuntimeError(RUNTIME_ERRORS.TEAL.INVALID_PROOF_LENGTH, {length: proof.length});
 		}
-		if (publicKey.length !== 32) {
+		if (publicKey.length !== publicKeyLength) {
 			throw new RuntimeError(RUNTIME_ERRORS.TEAL.INVALID_PUB_KEY_LENGTH, {length: publicKey.length});
 		}
-		if (this.vrfType === "VrfAlgorand") {
+		if (this.vrfType === vrfVerifyFieldTypes.VrfAlgorand) {
 			const hash = sha512(proof);
 			stack.push(convertToBuffer(hash, EncodingType.HEX));
 			stack.push(1n);
diff --git a/packages/runtime/src/lib/constants.ts b/packages/runtime/src/lib/constants.ts
index 43e22d39f..0d2a70afe 100644
--- a/packages/runtime/src/lib/constants.ts
+++ b/packages/runtime/src/lib/constants.ts
@@ -40,6 +40,10 @@ export const MAX_INNER_TRANSACTIONS = 16;
 export const ALGORAND_MAX_LOGS_COUNT = 32;
 export const ALGORAND_MAX_LOGS_LENGTH = 1024;
 
+export const publicKeyLength = 32;
+export const proofLength = 80;
+export const seedLength = 32;
+
 export const MAX_ALGORAND_ACCOUNT_ASSETS = 1000;
 export const MAX_ALGORAND_ACCOUNT_CREATED_APPS = 10;
 
@@ -478,6 +482,7 @@ OpGasCost[7] = {
 	...OpGasCost[6],
 	sha3_256: 130,
 	ed25519verify_bare: 1900,
+	vrf_verify : 5700,
 };
 
 export const enum MathOp {
@@ -525,6 +530,11 @@ export enum blockFieldTypes {
 	BlkSeed = "BlkSeed",
 };
 
+export enum vrfVerifyFieldTypes {
+    VrfAlgorand = "VrfAlgorand",
+	VrfStandard = "VrfStandard",
+};
+
 export enum TxFieldEnum {
 	FirstValidTime = "FirstValidTime",
 	TypeEnum = "TypeEnum",
diff --git a/packages/runtime/src/runtime.ts b/packages/runtime/src/runtime.ts
index 5bec2e48f..e561a36e1 100644
--- a/packages/runtime/src/runtime.ts
+++ b/packages/runtime/src/runtime.ts
@@ -23,9 +23,9 @@ import {
 	BlockFinalisationTime,
 	MAX_APP_PROGRAM_COST,
 	MaxExtraAppProgramPages,
+	seedLength,
 	TransactionTypeEnum,
-	ZERO_ADDRESS_STR
-} from "./lib/constants";
+	ZERO_ADDRESS_STR} from "./lib/constants";
 import { convertToString } from "./lib/parsing";
 import { LogicSigAccount } from "./logicsig";
 import { mockSuggestedParams } from "./mock/tx";
@@ -1193,7 +1193,7 @@ export class Runtime {
 		let timestamp: bigint | undefined;
 		let seed: Uint8Array | undefined;
 		if (this.store.blocks.size === 0) { //create genesis block
-			seed = nacl.randomBytes(32);
+			seed = nacl.randomBytes(seedLength);
 			timestamp = BigInt(Math.round(new Date().getTime() / 1000));
 		} else { //add another block
 			const lastBlock = this.store.blocks.get(this.round);
diff --git a/packages/runtime/test/src/interpreter/opcode-list.ts b/packages/runtime/test/src/interpreter/opcode-list.ts
index e606e5f92..91d241d7e 100644
--- a/packages/runtime/test/src/interpreter/opcode-list.ts
+++ b/packages/runtime/test/src/interpreter/opcode-list.ts
@@ -14,7 +14,6 @@ import { sha512_256 } from "js-sha512";
 import cloneDeep from "lodash.clonedeep";
 import { describe } from "mocha";
 import nacl from "tweetnacl";
-import { isGeneratorFunction } from "util/types";
 
 import { ExecutionMode } from "../../../build/types";
 import { AccountStore } from "../../../src/account";
@@ -170,13 +169,15 @@ import {
 import {
 	ALGORAND_ACCOUNT_MIN_BALANCE,
 	ASSET_CREATION_FEE,
+	blockFieldTypes,
 	DEFAULT_STACK_ELEM,
 	MAX_UINT8,
 	MAX_UINT64,
 	MaxTEALVersion,
 	MIN_UINT8,
+	vrfVerifyFieldTypes,
 	ZERO_ADDRESS,
-	blockFieldTypes,
+	seedLength,
 } from "../../../src/lib/constants";
 import {
 	bigEndianBytesToBigInt,
@@ -7619,7 +7620,7 @@ describe("Teal Opcodes", function () {
 			const op = new Block([blockFieldTypes.BlkSeed], 1, interpreter);
 			op.execute(stack);
 			const result = stack.pop();
-			assert.equal((result as Buffer).length, 32);
+			assert.equal((result as Buffer).length, seedLength);
 		});
 
 		it("Should return correct cost", function(){
@@ -7651,7 +7652,7 @@ describe("Teal Opcodes", function () {
 		})
 
 		it("Should return 1 and hash of proof for valid proof and verification key", function () {
-			const op = new VrfVerify(["VrfAlgorand"], 1);
+			const op = new VrfVerify([vrfVerifyFieldTypes.VrfAlgorand], 1);
 			stack.push(publicKey);
 			stack.push(proof);
 			stack.push(message);
@@ -7660,7 +7661,7 @@ describe("Teal Opcodes", function () {
 			assert.deepEqual(expectedResult, stack.pop());
 		});
 		it("Should throw error if pubKey size not equal 32", function(){
-			const op = new VrfVerify(["VrfAlgorand"], 1);
+			const op = new VrfVerify([vrfVerifyFieldTypes.VrfAlgorand], 1);
 			const wrongSizePubKey = Buffer.from("b6b4699f87d56126c9117");
 			stack.push(wrongSizePubKey);
 			stack.push(proof);
@@ -7668,7 +7669,7 @@ describe("Teal Opcodes", function () {
 			expectRuntimeError(() => op.execute(stack), RUNTIME_ERRORS.TEAL.INVALID_PUB_KEY_LENGTH);
 		})
 		it("Should throw error if proof size not equal 80", function(){
-			const op = new VrfVerify(["VrfAlgorand"], 1);
+			const op = new VrfVerify([vrfVerifyFieldTypes.VrfAlgorand], 1);
 			const wrongSizeProof = Buffer.from("b6b4699f87d56126c9117");
 			stack.push(publicKey);
 			stack.push(wrongSizeProof);
@@ -7676,7 +7677,7 @@ describe("Teal Opcodes", function () {
 			expectRuntimeError(() => op.execute(stack), RUNTIME_ERRORS.TEAL.INVALID_PROOF_LENGTH);
 		})
 		it("Should return correct cost", function(){
-			const op = new VrfVerify(["VrfAlgorand"], 1);
+			const op = new VrfVerify([vrfVerifyFieldTypes.VrfAlgorand], 1);
 			stack.push(publicKey);
 			stack.push(proof);
 			stack.push(message);
@@ -7684,7 +7685,7 @@ describe("Teal Opcodes", function () {
 			assert.equal(cost, 5700);
 		})
 		it("Should throw error when field = VrfStandard", function(){
-			const op = new VrfVerify(["VrfStandard"], 1);
+			const op = new VrfVerify([vrfVerifyFieldTypes.VrfAlgorand], 1);
 			stack.push(publicKey);
 			stack.push(proof);
 			stack.push(message);

From 11bf244582800d0178df5e39eca873040bfd555d Mon Sep 17 00:00:00 2001
From: sczembor <43810037+sczembor@users.noreply.github.com>
Date: Wed, 2 Nov 2022 21:07:19 +0100
Subject: [PATCH 23/24] update changelog

---
 CHANGELOG.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1b45ebcbb..3b1d21d43 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -56,6 +56,8 @@ from `algosdk` and sends it to the network.
 - Added support for `vrf_verify` opcode to `Runtime`. IMPORTANT: the opcode assumes the proof is always valid thus it will always return 1.
 - Added program length check on app deploy on the basis of extra pages in `runtime`.
 - Added logic signature and arguments size check in `runtime`.
+- Added support for `block` opcode to `Runtime`.
+- Added blocks to `Runtime`. It simulates the block generation by using radnom bytes generator as the first seed. The following seeds are MD5 hash of the seed from the previous block.
 
 #### @algo-builder/web
 - Added support for logic signature to `executeTx` method of `Webmode` for AlgoSigner, MyAlgo Wallet and Wallet Connect.

From fe8ff010f5cb9e68e90edcd728322e4e72fef31f Mon Sep 17 00:00:00 2001
From: sczembor <43810037+sczembor@users.noreply.github.com>
Date: Wed, 2 Nov 2022 21:11:16 +0100
Subject: [PATCH 24/24] fix bug

---
 packages/runtime/test/src/interpreter/opcode-list.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/runtime/test/src/interpreter/opcode-list.ts b/packages/runtime/test/src/interpreter/opcode-list.ts
index 91d241d7e..888cb4e56 100644
--- a/packages/runtime/test/src/interpreter/opcode-list.ts
+++ b/packages/runtime/test/src/interpreter/opcode-list.ts
@@ -7685,7 +7685,7 @@ describe("Teal Opcodes", function () {
 			assert.equal(cost, 5700);
 		})
 		it("Should throw error when field = VrfStandard", function(){
-			const op = new VrfVerify([vrfVerifyFieldTypes.VrfAlgorand], 1);
+			const op = new VrfVerify([vrfVerifyFieldTypes.VrfStandard], 1);
 			stack.push(publicKey);
 			stack.push(proof);
 			stack.push(message);