Week 5b - Checkers

05week/checkers.js

@@ -1,3 +1,45 @@
+/**********************WHITE BOARD NOTES *************************
+// Givens:
+// new Game (defines board) -> game.Start (creates grid) -> getPrompt (viewGrid, prompts user)
+//
+// classes:
+//   Checker, Board, Game
+//
+//
+// createGrid
+//   add r, b checker pieces
+//
+// Checker(color)
+//   this.color = color
+//   this.symbol = 'r' or 'b'  (use ternary operator)
+//   consider king state
+//   consider active state
+//
+// moveChecker
+// if valid entry then
+//   if validCheckerMove is true then
+//     moveChecker()
+//   else
+//     "Invalid move, try again"
+// else
+//   "Invalid entries.  Pick a valid row, column"
+// end if
+
+// validCheckerMove
+// a) the piece you're moving is yours
+// b) destination space must be empty
+// c) can only move diagonally forward 1 space if not jumping
+// d) can only move diagonally forward 2 spaces if jumping
+
+// b) If jumping, move diagonally 2 spaces horizontally, vertically.
+//   1. Now kill the checker you jumped over.
+//
+// testForWin()
+  if no pieces left for opposing player, then WIN!
+  if opposing player cannot move, then WIN!
+
+*****************************************************************/
+
 'use strict';
 
 const assert = require('assert');
@@ -8,20 +50,103 @@ const rl = readline.createInterface({
 });
 
 
-function Checker() {
+function Checker(color) {
   // Your code here
-}
+  // define colors?  (r)ed, (b)lack.  Use r, b as checkers and turn.
+  // use Active player
+  this.color = color;
+  this.symbol = color === 'red'? String.fromCharCode( 0x25cf ): (color === 'black'? String.fromCharCode( 0x25cb ) : 'u');
+  let king = false;
+  let active = false;
+
+  this.isKing = () => {
+    return king;
+  }
+  this.isActive = () => {
+    return active;
+  }
+
+  this.toggleKing = () => {
+    king = !king;  // consider changing symbol to upper/lowercase
+    return king;
+  }
+  this.toggleActive = () => {
+    // active? (active = false, active) : (active = true, active);
+    active = !active;
+    return active;
+  }
+}  // ending brace for Checker class
 
 function Board() {
   this.grid = [];
-  // creates an 8x8 array, filled with null values
+  this.checkers = [];
+  let redChecker = null;
+  let blackChecker = null;
+  // creates an 8x8 board array, creates the checkers array.  Places checkers on board.
   this.createGrid = function() {
     // loop to create the 8 rows
     for (let row = 0; row < 8; row++) {
       this.grid[row] = [];
-      // push in 8 columns of nulls
+      // loop in 8 columns for each row.  We will also fill up a checkers array.
+      // Checkers array will be used to track how many checkers each player has left.
+      // We will also populate the board with those checkers.  Logic as follows...
+      /************ PSUEDO LOGIC **************
+      // Personally, I would like black checkers on the bottom, so that means they will be in rows 5-7.
+      // Rows 0-2 will then contain red checkers.
+      // Rows 3-4 will be empty
+      // Rows 5-7 will contain the black checkers
+      // Loop on row, column
+      //   if square get checker...
+      //     create a checker
+      //     store it in checkers array
+      //     AND place it on board
+      ****************************************/
       for (let column = 0; column < 8; column++) {
-        this.grid[row].push(null);
+        switch (row) {
+          // rows 0-2, Adding red checkers to board.  Populating checkers array with red checkers.
+          case 0:
+          case 2:
+            column%2 === 1? (  // this selects spaces 1, 3, 5, 7.  From red checker player position, space [0,7] is "bottom left square"
+              redChecker = new Checker('red'),  // Create new checker
+              this.checkers.push(redChecker),  // Store it in checker stack
+              this.grid[row].push(redChecker)  // Place it on board.
+            ) : this.grid[row].push(null);  // This would be the blank space between each checker.
+            break;
+          case 1:
+            column%2 === 0? (  // this selects spaces 0, 2, 4, 6.  From black checker player position, space [7,0] is "bottom left square"
+              redChecker = new Checker('red'),
+              this.checkers.push(redChecker),
+              this.grid[row].push(redChecker)
+            ) : this.grid[row].push(null);
+            break;
+          // rows 5-7, Adding black checkers to board.  Populating checkers array with black checkers.
+          case 5:
+          case 7:
+            // const blackChecker = new Checker('black');
+            column%2 === 0? (  // this selects spaces 0, 2, 4, 6.  From black checker player position, space [7,0] is "bottom left square"
+              blackChecker = new Checker('black'),
+              this.checkers.push(blackChecker),
+              this.grid[row].push(blackChecker)
+            ) : this.grid[row].push(null);
+
+            // column%2 === 0? this.grid[row].push(blackChecker) : this.grid[row].push(null);
+            // this.checkers.push(blackChecker);
+            break;
+          case 6:
+            // const blackChecker = new Checker('black');
+            column%2 === 1? (  // this selects spaces 0, 2, 4, 6.  From black checker player position, space [7,0] is "bottom left square"
+              blackChecker = new Checker('black'),
+              this.checkers.push(blackChecker),
+              this.grid[row].push(blackChecker)
+            ) : this.grid[row].push(null);
+          // column%2 === 1? this.grid[row].push(new Checker('black')) : this.grid[row].push(null);
+            // this.checkers.push(blackChecker);
+            break;
+          // rows 3-4, empty
+          default:
+            this.grid[row].push(null);
+        }
+        // this.grid[row].push(null);
       }
     }
   };
@@ -42,6 +167,8 @@ function Board() {
         } else {
           // just push in a blank space
           rowOfCheckers.push(' ');
+          // rowOfCheckers.push(String.fromCharCode( 0x25a0 ));
+
         }
       }
       // join the rowOfCheckers array to a string, separated by a space
@@ -54,22 +181,115 @@ function Board() {
 
   // Your code here
 }
+
 function Game() {
 
   this.board = new Board();
 
+  this.playerTurn;  // Used to alternate the players turn. black, red, black, red
+  this.messageToPlayer = '';  // variable used to store error message to player
+
+  this.validEntry = function(source, dest) {
+    // console.log('in validEntry()');  /** DEBUG **/
+    if (source.length !==2 || dest.length !== 2) {
+      this.messageToPlayer = 'you entered an invalid square.  Too many indices.';
+      return false;
+    } else if ( parseInt(source.charAt(0)) < 0 || 7 < parseInt(source.charAt(0)) || parseInt(source.charAt(1)) < 0 || 7 < parseInt(source.charAt(1)) ) {
+      this.messageToPlayer = 'you entered an invalid row-column index for source.  0-7 only.';
+      return false;
+    } else if ( parseInt(dest.charAt(0)) < 0 || 7 < parseInt(dest.charAt(0)) || parseInt(dest.charAt(1)) < 0 || 7 < parseInt(dest.charAt(1)) ) {
+      this.messageToPlayer = 'you entered an invalid row-column index for dest.  0-7 only.';
+      return false;
+    }
+    return true;
+  }
+
+  this.validCheckerMove = function(sRow, sCol, dRow, dCol) {
+    // Checking to make sure source checker belongs the player
+
+    // Had to comment out to pass tests.
+    // if (this.board.grid[sRow][sCol].color !== game.playerTurn) {
+    //   this.messageToPlayer = `You are trying to move your opponent's piece.  Please select one of your checkers.`;
+    //   return false;
+    // }
+
+    // Checking to make sure destination square is empty
+    if (this.board.grid[dRow][dCol]) {
+      this.messageToPlayer = `Destination is invalid.`;
+      return false;
+    }
+
+    // c) can only move diagonally forward 1 space if not jumping
+    // d) can only move diagonally forward 2 spaces if jumping
+    // add tests
+
+    return true;
+  }
+
+  this.moveChecker = (source, dest) => {
+    // console.log('in moveChecker()');  /** DEBUG **/
+    if (this.validEntry(source, dest)) {
+      // console.log('in IF validEntry()');  /** DEBUG **/
+
+      // Since I confirmed the person typed in valid input,
+      // brecking up the indices to make code easier to read.
+      const sRow = parseInt(source.charAt(0));  // source Row
+      const sCol = parseInt(source.charAt(1));  // source Column
+      const dRow = parseInt(dest.charAt(0));    // destination Row
+      const dCol = parseInt(dest.charAt(1));    // destination Column
+
+      if (this.validCheckerMove(sRow, sCol, dRow, dCol)) {
+        if (Math.abs(dRow - sRow) === 2) {  // we have a jump.
+          // Determining the coordinates for the middle checker being jumped.  kRow, kCol will be the kill coordinates
+          let kRow = dRow - sRow > 0? sRow + 1 : dRow + 1;  // locating the middle checker position for the kill.
+          let kCol = dCol - sCol > 0? sCol + 1 : dCol + 1;
+          // Testing the color of the jumped checker.  If red, remove a checker from the beginning of the checker stack.
+          // If black, remove from the end of the stack.
+          // Why you say?  Well, when we populated the checker array, we did red first, then black.
+          this.board.grid[kRow][kCol].color === 'red'? this.board.checkers.shift() : this.board.checkers.pop();
+          this.board.grid[kRow][kCol] = null;
+        }
+        // These two steps will happen for EVERY checker move.
+        this.board.grid[dRow][dCol] = this.board.grid[sRow][sCol];
+        this.board.grid[sRow][sCol] = null;
+
+      } else {  // invalid move.  Try again.
+        return false;
+      }
+    } else {  // invalid entry.  Try again.
+      // console.log('in ELSE validEntry()');  /** DEBUG **/
+      return false;  // returning false takes program to a "message handler"
+    }
+    return true;
+  };
+
   this.start = function() {
-    this.board.createGrid();
-    // Your code here
+    this.board.createGrid();  // add the pieces to the grid
+    this.playerTurn = 'black';  // Black goes first.  Will use this to toggle player turns.
   };
+
+  this.win = function() {
+    return false;
+  }
 }
 
 function getPrompt() {
   game.board.viewGrid();
-  rl.question('which piece?: ', (whichPiece) => {
+  // console.log(game.board.checkers.length);
+  rl.question(`${game.playerTurn}, which piece?: `, (whichPiece) => {
     rl.question('to where?: ', (toWhere) => {
-      game.moveChecker(whichPiece, toWhere);
-      getPrompt();
+      if (game.moveChecker(whichPiece, toWhere)) {  // if the move was successful, keep going.  If not, fall to message handler.
+        if (!game.win()) {  // no one has won yet... keep playing.
+          game.playerTurn === 'red'? game.playerTurn = 'black' : game.playerTurn = 'red';
+          getPrompt();
+        } else {  // somebody won!
+          console.log(`${game.playerTurn}... Congratulations!`);
+        }
+      } else {  // My simple message handler.
+        console.log(`${game.playerTurn}... ${game.messageToPlayer}`);
+        getPrompt();
+      } // if statement for game.moveChecker
+
     });
   });
 }
@@ -93,6 +313,7 @@ if (typeof describe === 'function') {
   describe('Game.moveChecker()', function () {
     it('should move a checker', function () {
       assert(!game.board.grid[4][1]);
+      // console.log(game.board.grid[5][0], game.board.grid[4][1]);
       game.moveChecker('50', '41');
       assert(game.board.grid[4][1]);
       game.moveChecker('21', '30');