#!/usr/bin/env ruby

require 'curses'

module MyHunt
  class Cell
    attr_accessor :mine,
                  :open

    def initialize( mine: false, open: false )
      @mine = mine
      @open = open
    end

    def explore
      @open = true

      @mine
    end
  end

  class Board
    attr_reader :width,
                :height,
                :field,
                :explorer_x,
                :explorer_y

    def initialize( number_of_mines = 20, height = 8, width = 16 )
      @height = height
      @width = width
      @explorer_x = 0
      @explorer_y = 0
      @field = {}

      @width.times do |x|
        @height.times do |y|
          @field[[x, y]] = Cell.new( open: x.zero? && y.zero? )
        end
      end

      placed_mines = 0
      while placed_mines < number_of_mines
        coordinates = [rand( @width ), rand( @height )]
        next if coordinates == [0, 0]
        next if @field[ coordinates ].mine

        @field[ coordinates ].mine = true
        placed_mines += 1
      end
    end

    def update_explorer_location( direction )
      case direction
      when 'up'
        @explorer_y -= 1 if @explorer_y.positive?
      when 'right'
        @explorer_x += 1 if @explorer_x < (@width - 1)
      when 'down'
        @explorer_y += 1 if @explorer_y < (@height - 1)
      when 'left'
        @explorer_x -= 1 if @explorer_x.positive?
      when 'up-right'
        if @explorer_x < (@width - 1) && @explorer_y.positive?
          @explorer_x += 1
          @explorer_y -= 1
        end
      when 'down-right'
        if @explorer_x < (@width - 1) && @explorer_y < (@height - 1)
          @explorer_x += 1
          @explorer_y += 1
        end
      when 'down-left'
        if @explorer_x.positive? && @explorer_y < (@height - 1)
          @explorer_x -= 1
          @explorer_y += 1
        end
      when 'up-left'
        if @explorer_x.positive? && @explorer_y.positive?
          @explorer_x -= 1
          @explorer_y -= 1
        end
      end
    end

    def move( direction )
      update_explorer_location( direction )

      { dead: @field[[@explorer_x, @explorer_y]].explore,
        victory: @explorer_x == (@width - 1) && @explorer_y == (@height - 1) }
    end

    def count_nearby_mines
      counter = 0

      [@explorer_x - 1, @explorer_x, @explorer_x + 1].each do |x|
        [@explorer_y - 1, @explorer_y, @explorer_y + 1].each do |y|
          next if x.negative?
          next if y.negative?
          next if x == @width
          next if y == @height
          next if x == @explorer_x && y == @explorer_y

          counter += 1 if @field[[x, y]].mine
        end
      end

      counter
    end
  end
end

field = MyHunt::Board.new

def display_curses( field, state = { dead: false, victory: false } )
  Curses.setpos 0, 0

  if state[:dead]
    Curses.addstr 'You died! :('
  elsif state[:victory]
    Curses.addstr 'You won!! :)'
  else
    Curses.addstr "nearby: #{field.count_nearby_mines}"
  end

  field.height.times do |y|
    field.width.times do |x|
      Curses.setpos y + 2, x
      if [field.explorer_x, field.explorer_y] == [x, y]
        Curses.addch 'o'
      elsif [field.width, field.height] == [x + 1, y + 1]
        Curses.addch '_'
      elsif field.field[[x, y]].open
        Curses.addch field.field[[x, y]].mine ? '*' : ' '
      else
        Curses.addch 'H'
      end
    end
  end

  Curses.refresh
end

Curses.init_screen
Curses.cbreak
Curses.noecho
Curses.stdscr.keypad = true
at_exit do
  Curses.close_screen
end
finished = false

display_curses( field )

loop do
  direction = ''
  ch = Curses.getch
  if finished
    begin
      case ch
      when 'r'
        field = MyHunt::Board.new
        finished = false
      else
        break
      end
    rescue Curses::RequestDeniedError
      'prout'
    end
  else
    begin
      case ch
      when '1'
        direction = 'down-left'
      when '2', Curses::KEY_DOWN
        direction = 'down'
      when '3'
        direction = 'down-right'
      when '4', Curses::KEY_LEFT
        direction = 'left'
      when '6', Curses::KEY_RIGHT
        direction = 'right'
      when '7'
        direction = 'up-left'
      when '8', Curses::KEY_UP
        direction = 'up'
      when '9'
        direction = 'up-right'
      when 'q'
        break
      end
    rescue Curses::RequestDeniedError
      'prout'
    end
  end

  state = field.move( direction )
  finished = state[:dead] || state[:victory]
  display_curses( field, state )
end