From 03f0ac49d99e64e0a9bab42fe9d8a48cdfc32d58 Mon Sep 17 00:00:00 2001
From: Jeremy Kaplan <jdkaplan@metagram.net>
Date: Fri, 13 Dec 2019 16:15:00 -0800
Subject: [PATCH] 2019: Day 13 Part 2

---
 2019/day13/part2.rb | 196 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 196 insertions(+)
 create mode 100644 2019/day13/part2.rb

diff --git a/2019/day13/part2.rb b/2019/day13/part2.rb
new file mode 100644
index 0000000..38c975a
--- /dev/null
+++ b/2019/day13/part2.rb
@@ -0,0 +1,196 @@
+# frozen_string_literal: true
+
+require 'io/console'
+require_relative 'intcode'
+
+Cell = Struct.new(:x, :y)
+
+class Screen
+  attr_reader :tiles
+
+  def initialize
+    @tiles = {}
+  end
+
+  def draw(x, y, tile)
+    @tiles[Cell.new(x, y)] = tile
+  end
+
+  def to_s
+    tl, br = corners
+
+    s = String.new
+    (tl.y..br.y).each do |y|
+      (tl.x..br.x).each do |x|
+        s << char(Cell.new(x, y))
+      end
+      s << "\n"
+    end
+    s
+  end
+
+  def ball
+    @tiles.each_pair do |cell, value|
+      return cell if value == :ball
+    end
+    nil
+  end
+
+  def paddle
+    @tiles.each_pair do |cell, value|
+      return cell if value == :horizontal_paddle
+    end
+    nil
+  end
+
+  private
+
+  def corners
+    min_x = +Float::INFINITY
+    min_y = +Float::INFINITY
+    max_x = -Float::INFINITY
+    max_y = -Float::INFINITY
+
+    @tiles.keys.each do |p|
+      min_x = [min_x, p.x].min
+      min_y = [min_y, p.y].min
+      max_x = [max_x, p.x].max
+      max_y = [max_y, p.y].max
+    end
+
+    upper_left = Cell.new(min_x, min_y)
+    lower_right = Cell.new(max_x, max_y)
+    [upper_left, lower_right]
+  end
+
+  def char(cell)
+    tile = @tiles[cell]
+    case tile
+    when :empty
+      ' '
+    when :wall
+      '#'
+    when :block
+      'x'
+    when :horizontal_paddle
+      '-'
+    when :ball
+      'o'
+    when nil
+      ' '
+    else
+      raise StandardError, "Unexpected tile #{tile}"
+    end
+  end
+end
+
+class DoneExecuting < StandardError; end
+
+class Game
+  def initialize(program, screen, joystick)
+    @computer = Intcode::Computer.new(program.as_memory) { on_input }
+    @screen = screen
+    @joystick = joystick
+    @score = nil
+  end
+
+  def on_input
+    @joystick.read
+  end
+
+  def run
+    loop do
+      step
+      system 'clear'
+      puts "Score: #{@score}"
+      puts @screen
+    rescue DoneExecuting
+      return nil
+    end
+  end
+
+  def step
+    x = next_output
+    y = next_output
+    tile_id = next_output
+
+    if x == -1 && y.zero?
+      @score = tile_id
+      return
+    end
+
+    case tile_id
+    when 0
+      @screen.draw(x, y, :empty)
+    when 1
+      @screen.draw(x, y, :wall)
+    when 2
+      @screen.draw(x, y, :block)
+    when 3
+      @screen.draw(x, y, :horizontal_paddle)
+    when 4
+      @screen.draw(x, y, :ball)
+    else
+      raise StandardError, "Unexpected tile ID: #{tile_id}"
+    end
+  end
+
+  def next_output
+    out = nil
+    out = tick until out
+    out
+  end
+
+  def tick
+    ret = @computer.tick
+    raise DoneExecuting if ret == :done_executing
+
+    ret
+  end
+end
+
+class ConsoleJoystick
+  def read
+    inp = nil
+    inp = get_input until inp
+    inp
+  end
+
+  def get_input
+    ch = STDIN.getch
+    exit 1 if ch == "\u0003"
+
+    ch += STDIN.getch if ch == "\e"
+    ch += STDIN.getch if ch == "\e["
+    case ch
+    when "\e[D"
+      # left
+      -1
+    when "\e[C"
+      # right
+      +1
+    when ' '
+      # space
+      0
+    else
+      puts "Invalid input: #{ch}"
+    end
+  end
+end
+
+class RobotJoystick
+  def initialize(screen)
+    @screen = screen
+  end
+
+  def read
+    @screen.ball.x <=> @screen.paddle.x
+  end
+end
+
+program = Intcode.read(File.join(__dir__, 'input-cheating'))
+screen = Screen.new
+joystick = RobotJoystick.new(screen)
+# joystick = ConsoleJoystick.new
+game = Game.new(program, screen, joystick)
+game.run