From 68b4a4fb90de8f05eaa4142af89094ebf24659c9 Mon Sep 17 00:00:00 2001
From: Liran Tal <liran.tal@gmail.com>
Date: Fri, 8 Feb 2019 11:40:23 +0200
Subject: [PATCH] feat(streams): refactor streams and buffer usage

---
 index.js | 100 ++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 58 insertions(+), 42 deletions(-)

diff --git a/index.js b/index.js
index 196f2af..bde6ba5 100644
--- a/index.js
+++ b/index.js
@@ -1,44 +1,60 @@
-var PNG = require('png-js');
-var charm = require('charm');
-var x256 = require('x256');
-var buffers = require('buffers');
-var es = require('event-stream');
-
-var Stream = require('stream').Stream;
-
-module.exports = function (opts) {
-    if (!opts) opts = {};
-    if (!opts.cols) opts.cols = 80;
-    
-    var c = charm();
-    var bufs = buffers();
-    
-    var ws = es.writeArray(function (err, bufs) {
-        var data = buffers(bufs).slice();
-        var png = new PNG(data);
-        
-        png.decode(function (pixels) {
-            var dx = png.width / opts.cols;
-            var dy = 2 * dx;
-            
-            for (var y = 0; y < png.height; y += dy) {
-                for (var x = 0; x < png.width; x += dx) {
-                    var i = (Math.floor(y) * png.width + Math.floor(x)) * 4;
-                    
-                    var ix = x256([ pixels[i], pixels[i+1], pixels[i+2] ]);
-                    if (pixels[i+3] > 0) {
-                        c.background(ix).write(' ');
-                    }
-                    else {
-                        c.display('reset').write(' ');
-                    }
-                }
-                c.display('reset').write('\r\n');
-            }
-            
-            c.display('reset').end();
-        });
+var PNG = require("png-js");
+var charm = require("charm");
+var x256 = require("x256");
+
+var { Duplex } = require("stream");
+
+class PictureTube extends Duplex {
+  constructor(opts = {}) {
+    super();
+    this.data = [];
+    this.cols = opts.cols || 80;
+
+    this.c = charm();
+
+    this.c.on("data", chunk => {
+      this.push(chunk);
     });
-    
-    return es.duplex(ws, c);
+
+    this.c.on("end", () => {
+      this.emit("end");
+    });
+  }
+
+  _read() {}
+
+  _write(chunk, encoding, callback) {
+    this.data.push(chunk);
+    callback();
+  }
+
+  _final(callback) {
+    var png = new PNG(Buffer.concat(this.data));
+
+    png.decode(pixels => {
+      var dx = png.width / this.cols;
+      var dy = 2 * dx;
+
+      for (var y = 0; y < png.height; y += dy) {
+        for (var x = 0; x < png.width; x += dx) {
+          var i = (Math.floor(y) * png.width + Math.floor(x)) * 4;
+
+          var ix = x256([pixels[i], pixels[i + 1], pixels[i + 2]]);
+          if (pixels[i + 3] > 0) {
+            this.c.background(ix).write(" ");
+          } else {
+            this.c.display("reset").write(" ");
+          }
+        }
+        this.c.display("reset").write("\r\n");
+      }
+
+      this.c.display("reset").end();
+      callback();
+    });
+  }
+}
+
+module.exports = opts => {
+  return new PictureTube(opts);
 };