Merge branch 'master' into b-listtags

build.gradle

@@ -14,6 +14,7 @@ repositories {
 
 dependencies  {
     testImplementation 'org.junit.jupiter:junit-jupiter:5.5.0'
+    implementation 'com.google.code.gson:gson:2.8.6'
 }
 
 application {

src/main/java/executor/command/CommandConvert.java

@@ -0,0 +1,192 @@
+package executor.command;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.math.RoundingMode;
+import java.net.URL;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import executor.task.TaskList;
+import interpreter.Parser;
+import ui.Ui;
+import ui.Wallet;
+import java.math.BigDecimal;
+
+/**
+ * This command helps to convert user entered currency amount into another country's currency amount using api call.
+ */
+public class CommandConvert extends Command {
+    private String from;
+    private String to;
+    private Double amount;
+    private Double exchangeRate = 0.00;
+
+    /**
+     * Constructor for the CommandConvert class.
+     * @param userInput this is the userInput from the CLI
+     */
+    public CommandConvert(String userInput) {
+        this.userInput = userInput;
+        this.commandType = CommandType.CONVERT;
+        this.amount = extractAmount(this.commandType, userInput);
+        this.from = getCurrencyCovertFrom(userInput);
+        this.to = getCurrencyConvertTo(userInput);
+        this.description = "Command that converts the user input cash amount from"
+                + " one currency to another and print it in the User Interface.";
+    }
+
+
+    @Override
+    public void execute(Wallet wallet) {
+        Double convertedAmount = this.convertCurrency(this.getFrom(), this.getTo(), this.getAmount());
+        Ui.dukeSays(this.result(convertedAmount) + rateUsed());
+        Ui.printSeparator();
+    }
+
+
+    @Override
+    public void execute(TaskList taskList) {
+
+    }
+
+
+    /**
+     * extractAmount parses the user input from CLI to get the amount which the user wishes to convert.
+     * @param commandType this is the type of command
+     * @param userInput takes the user entered input from CLI
+     * @return the amount which user wishes to convert is returned
+     */
+    private Double extractAmount(CommandType commandType, String userInput) {
+        String amountStr = Parser.parseForPrimaryInput(commandType, userInput);
+        return Double.parseDouble(amountStr);
+    }
+
+    /**
+     * getCurrencyConvertFrom parses user input for the flag "from".
+     * @param userInput this is the user entered input from CLI
+     * @return this function returns the 3 character unique string representing the currency to convert from
+     */
+    private String getCurrencyCovertFrom(String userInput) {
+        String fromStr = Parser.parseForFlag("from", userInput);
+        return fromStr;
+    }
+
+    /**
+     * getCurrencyConvertTo parses the user input for the flag "to".
+     * @param userInput this is the user entered input from CLI
+     * @return this function return the 3 character unique string representing the currency to covert to
+     */
+    private String getCurrencyConvertTo(String userInput) {
+        String toStr = Parser.parseForFlag("to", userInput);
+        return toStr;
+    }
+
+    /**
+     * consultCurrencyApi is a function which gets the JSON object from the api.
+     * @param from String is the country code from which we are converting currency
+     * @param to String is the country code to which we are converting the currency
+     * @return this function returns a string version of the json object or else it will return null
+     */
+    private String consultCurrencyApi(String from, String to) {
+        try {
+            URL url = new URL("https://api.ratesapi.io/api/latest?base=" + from + "&symbols=" + to);
+            BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
+            String line;
+            String completeJson = "";
+            while (null != (line = reader.readLine())) {
+                completeJson += line;
+            }
+            return completeJson;
+        } catch (Exception ex) {
+            ex.printStackTrace();
+            return null;
+        }
+    }
+
+    /**
+     * convertCurrency is a function used to loop through the string version of the json.
+     * @param from String is the country code from which we are converting currency
+     * @param to String is the country code to which we are converting the currency
+     * @param amount this is amount of currency which the user wants to convert
+     * @return this function returns the converted amount of the currency or else returns null
+     */
+    private Double convertCurrency(String from, String to, Double amount) {
+        try {
+            String json = consultCurrencyApi(from,to);
+            if (json != null) {
+                JsonObject jsonObject = new JsonParser().parse(json).getAsJsonObject();
+                String rate = jsonObject.getAsJsonObject("rates").get(to).getAsString();
+                BigDecimal exchangeRate = new BigDecimal(rate);
+                double exRate = exchangeRate.doubleValue();
+                setExchangeRate(exRate);
+                double convertedAmount = exRate * amount;
+                return convertedAmount;
+            }
+        } catch (Exception e) {
+            Ui.dukeSays(e.getMessage());
+            Ui.dukeSays(Ui.LINE);
+            Ui.dukeSays("Please enter in the following format : "
+                    + "convert 2000 /from USD /to EUR");
+        }
+        return null;
+    }
+
+    /**
+     * result basically returns the to.string() version of the output that the user will be shown
+     * @param convertedAmount this is amount which was converted into
+     * @return string of output is returned
+     */
+    private String result(Double convertedAmount) {
+        convertedAmount = roundByDecimalPlace(convertedAmount, 2);
+        return "DUKE$$$ has converted " + this.from
+                + " " + roundByDecimalPlace(this.amount, 2) + " "
+                + "to" + " "
+                + this.to + " " + convertedAmount + "\n";
+    }
+
+    /**
+     * roundByDecimalPlace is basically a function to round the values to a specific number of decimal places.
+     * @param value this is the value which we want to round
+     * @param places number of decimal places
+     * @return the rounded double value is returned as the output
+     */
+    private double roundByDecimalPlace(double value, int places) {
+        if (places < 0) {
+            throw new IllegalArgumentException();
+        }
+
+        BigDecimal bd = BigDecimal.valueOf(value);
+        bd = bd.setScale(places, RoundingMode.HALF_UP);
+        return bd.doubleValue();
+    }
+
+
+    /**
+     * rateUsed is a function that helps to display the exchange rate which was used for the conversion.
+     * @return string version of the exchange rate is displayed
+     */
+    private String rateUsed() {
+        return "Exchange rate used = " + this.getExchangeRate().toString() + "\n";
+    }
+
+    private String getFrom() {
+        return from;
+    }
+
+    private String getTo() {
+        return to;
+    }
+
+    private Double getAmount() {
+        return amount;
+    }
+
+    public Double getExchangeRate() {
+        return exchangeRate;
+    }
+
+    private void setExchangeRate(Double exchangeRate) {
+        exchangeRate = roundByDecimalPlace(exchangeRate, 3);
+        this.exchangeRate = exchangeRate;
+    }
+}

src/main/java/executor/command/CommandGetSpendingByMonth.java

@@ -0,0 +1,77 @@
+package executor.command;
+
+import executor.task.TaskList;
+import interpreter.Parser;
+import ui.ReceiptTracker;
+import ui.Ui;
+import ui.Wallet;
+
+public class CommandGetSpendingByMonth extends Command {
+    protected String userInput;
+
+    /**
+     * Constructor to explain about the command.
+     * @param userInput is the input from the user
+     */
+    public CommandGetSpendingByMonth(String userInput) {
+        this.commandType = CommandType.EXPENDED;
+        this.userInput = userInput;
+        this.description = "Provides the user the total expenditure for the month stated. "
+                + "FORMAT: expended <month> /year<year>";
+    }
+
+    @Override
+    public void execute(TaskList taskList) {
+    }
+
+    @Override
+    public void execute(Wallet wallet) {
+        ReceiptTracker receiptsInMonth = new ReceiptTracker();
+        String monthStr = Parser.parseForPrimaryInput(CommandType.EXPENDED, userInput);
+        int month = monthStrToInt(monthStr);
+        if (month != 0) {
+            int year = Integer.parseInt(Parser.parseForFlag("year", userInput));
+            receiptsInMonth = wallet.getReceipts().findReceiptByMonthYear(month, year);
+            Double totalMoney = receiptsInMonth.getTotalCashSpent();
+            Ui.dukeSays("The total amount of money spent in " + monthStr + " " + year + " : " + totalMoney);
+        } else {
+            Ui.dukeSays("Invalid input, CORRECT FORMAT : expended <month> <year> ");
+        }
+    }
+
+    /**
+     * Returns the corresponding month value.
+     * @param month is the name of month from the userInput
+     * @return the value of month, eg: march --> 3.
+     */
+    public int monthStrToInt(String month) {
+        switch (month) {
+        case "january":
+            return 1;
+        case "february":
+            return 2;
+        case "march":
+            return 3;
+        case "april":
+            return 4;
+        case "may":
+            return 5;
+        case "june":
+            return 6;
+        case "july":
+            return 7;
+        case "august":
+            return 8;
+        case "september":
+            return 9;
+        case "october":
+            return 10;
+        case "november":
+            return 11;
+        case "december":
+            return 12;
+        default:
+            return 0;
+        }
+    }
+}

src/main/java/executor/command/CommandType.java

@@ -23,6 +23,8 @@ public enum CommandType {
     RECUR(CommandNewTask.class),
     FDURATION(CommandNewTask.class),
     TAGLIST(CommandListTag.class),
+    EXPENDED(CommandGetSpendingByMonth.class),
+    CONVERT(CommandConvert.class),
     ERROR(CommandError.class);
 
     private final Class commandClass;

src/main/java/ui/ReceiptTracker.java

@@ -2,6 +2,7 @@
 
 import duke.exception.DukeException;
 
+import java.time.LocalDate;
 import java.util.ArrayList;
 import java.util.HashMap;
 
@@ -90,6 +91,22 @@ public ReceiptTracker findReceiptsByTag(String tag) {
         return taggedReceipts;
     }
 
+    /**
+     * Finds all the receipts that corresponds to that month and year.
+     * @param month is the month given by the user
+     * @param year is the year given by the user
+     * @return ArrayList containing all the receipts which corresponds to year and month
+     */
+    public ReceiptTracker findReceiptByMonthYear(int month, int year) {
+        ReceiptTracker receiptByMonthYear = new ReceiptTracker();
+        for (Receipt receipt : this) {
+            if ((receipt.getDate().getMonthValue() == month) && (receipt.getDate().getYear() == year)) {
+                receiptByMonthYear.addReceipt(receipt);
+            }
+        }
+        return receiptByMonthYear;
+    }
+
     // -- Boolean Functions
     /**
      * Checks if a tag has been registered previously.