From 61bbd00f6d17ade5bf4feaf49b8192ae38d0d00f Mon Sep 17 00:00:00 2001
From: Alberto Venturini <aventurini@gmail.com>
Date: Mon, 28 Oct 2019 21:33:45 +0200
Subject: [PATCH] Add functions to extract rows, colums and blocks

---
 spec/board_spec.cr | 33 +++++++++++++++++++++++++++++++--
 src/board.cr       | 43 +++++++++++++++++++++++++++++++++----------
 2 files changed, 64 insertions(+), 12 deletions(-)

diff --git a/spec/board_spec.cr b/spec/board_spec.cr
index 092142d..aa53a45 100644
--- a/spec/board_spec.cr
+++ b/spec/board_spec.cr
@@ -3,14 +3,43 @@ require "./spec_helper"
 describe Sudoku::Board do
 
   it "initialized grid with nil values" do
-    board = Sudoku::Board.new(8, 8)
+    board = Sudoku::Board.new(9, 3)
     board.get(0, 0).should eq nil
   end
 
+  it "raises exception if board size is not divisible by block size" do
+    expect_raises(Sudoku::BoardException) do
+      Sudoku::Board.new(9, 4)
+    end
+  end
+
   it "puts numbers correctly" do
-    board = Sudoku::Board.new(8, 8)
+    board = Sudoku::Board.new(9, 3)
     board.put(1, 0, 0)
     board.get(0, 0).should eq 1
   end
 
+  it "extracts rows correctly" do
+    row = 1
+    board = Sudoku::Board.new(4, 2)
+    (0..3).each { |i| board.put(i, i, row) }
+    board.extract_row(row).should eq [0, 1, 2, 3]
+  end
+
+  it "extracts columns correctly" do
+    column = 2
+    board = Sudoku::Board.new(4, 2)
+    (0..3).each { |i| board.put(i, column, i) }
+    board.extract_column(column).should eq [0, 1, 2, 3]
+  end
+
+  it "extracts blocks correctly" do
+    board = Sudoku::Board.new(4, 2)
+    board.put(42, 2, 0)
+    board.put(43, 3, 0)
+    board.put(44, 2, 1)
+    board.put(45, 3, 1)
+    board.extract_block(3, 1).should eq [[42, 43], [44, 45]]
+  end
+
 end
diff --git a/src/board.cr b/src/board.cr
index 9a45cc8..7dcd152 100644
--- a/src/board.cr
+++ b/src/board.cr
@@ -1,27 +1,50 @@
 
 module Sudoku
 
+  class BoardException < Exception
+  end
+
   class Board
 
-    alias Value = Nil | Int8
-
-    enum State
-      Valid
-      Invalid
-    end
+    alias Value = Nil | Int32
 
+    @grid : Array(Array(Value))
     getter grid
 
-    def initialize(@width : Int8, @height : Int8)
-      @grid = Array(Value).new(@width * @height, nil)
+    def initialize(@size : Int32, @block_size : Int32)
+      raise BoardException.new() unless @size.divisible_by?(@block_size)
+      @grid = Array(Array(Value)).new(@size) { Array(Value).new(@size, nil) }
     end
 
     def put(value : Value, x, y)
-      @grid[y * @width + x] = value
+      @grid[y][x] = value
     end
 
     def get(x, y)
-      @grid[y * @width + x]
+      @grid[y][x]
+    end
+
+    def check_valid(value : Value, x, y)
+
+    end
+
+    def extract_row(y)
+      @grid[y]
+    end
+
+    def extract_column(x)
+      (0..@size - 1).map { |i| get(x, i) }
+    end
+
+    def extract_block(x, y)
+      block_start_x = x - (x % @block_size)
+      block_start_y = y - (y % @block_size)
+
+      (block_start_y..block_start_y + @block_size - 1).map { |j|
+        (block_start_x..block_start_x + @block_size - 1).map { |i|
+          get(i, j)
+        }
+      }
     end
       
   end