--[[
Author: TheOriginalBIT
Version: 1.1.2
Created: 5 May 2013
Last Update: 5 May 2013

License:

COPYRIGHT NOTICE
Copyright © 2013 Joshua Asbury a.k.a TheOriginalBIT [theoriginalbit@gmail.com]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
copies of the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

-The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
-Visible credit is given to the original author.
-The software is distributed in a non-profit way.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
]]--

local function clear(col) term.setBackgroundColor(col or colors.black) term.clear() term.setCursorPos(1,1) end
-- function thanks to Mads... found here: http://www.computercraft.info/forums2/index.php?/topic/11771-print-coloured-text-easily/page__p__105389#entry105389
local function writeWithFormat(...) local s = "&0" for k, v in ipairs(arg) do s = s .. v end s = s .. "&0" local fields = {} local lastcolor, lastpos = "0", 0 for pos, clr in s:gmatch"()&(%x)" do table.insert(fields, {s:sub(lastpos + 2, pos - 1), lastcolor}) lastcolor, lastpos = clr , pos end for i = 2, #fields do term.setTextColor(2 ^ (tonumber(fields[i][2], 16))) write(fields[i][1]) end end
-- modification of Mads' function to get the length of the string without the color modifiers
local function countFormatters(text) return #(text:gsub("()&(%x)", '')) end
-- print a color formatted string in the center of the screen
local function cwriteWithFormat(text, y) local sw,sh = term.getSize() local _,cy = term.getCursorPos() term.setCursorPos((sw-countFormatters(text))/2+(countFormatters(text) % 2 == 0 and 1 or 0), y or cy) writeWithFormat(text) end
-- writes the text at the give location

local sw, sh = term.getSize()

local PLAYER_KEYS = {
  [1] = { up = 17, down = 31 },
  [2] = { up = 24, down = 38 }
}

local PLAYER_PADDLES = {}
local BALL = {}

local PADDLE_HEIGHT = 5

local keyPressed
local renderRequired = true

local lastBallMove = os.clock()

local function setupBall()
  BALL.pos = { x = math.ceil(sw / 2), y = math.ceil(sh / 2) }
  BALL.dir = { x = (math.random(1,2) == 2 and 1 or -1), y = 0 }
end

local function setupPaddles()
  PLAYER_PADDLES[1] = { x = (2) , y = math.ceil(sh / 2 - 2), lastMove = os.clock() }
  PLAYER_PADDLES[2] = { x = (sw - 1) , y = math.ceil(sh / 2 - 2), lastMove = os.clock() }
end

local function processInput()
  os.startTimer(0.1) -- input timeout
  local event = { os.pullEvent() }
  if event[1] == 'key' then
    for i = 1, 2 do
      if event[2] == PLAYER_KEYS[i].up or event[2] == PLAYER_KEYS[i].down then
        keyPressed = event[2]
        break
      end
    end
  end
end

local function moveBall(x, y)
  BALL.pos.x = BALL.pos.x + x
  BALL.pos.y = BALL.pos.y + y
end

local function checkWallCollision()
  return (BALL.pos.y < 1 or BALL.pos.y > sh)
end

local function checkPaddleCollision()
  local playerToCheck = BALL.dir.x == 1 and 2 or 1
  for i = 1, 2 do
    local playerX = PLAYER_PADDLES[i].x
    local playerMinY = PLAYER_PADDLES[i].y
    local playerMaxY = playerMinY + 4
    if (BALL.pos.x == playerX and BALL.pos.y >= playerMinY and BALL.pos.y <= playerMaxY) then
      return true
    end
  end

  return false
end

local function checkGoalCollision()
  return (BALL.pos.x < 1 or BALL.pos.x > sw)
end

local function update()
  term.setCursorPos(1, 1)
  term.setTextColor(colors.black)

  local ballMoved = false
  if os.clock() - lastBallMove >= 0.2 then
    ballMoved = true
    lastBallMove = os.clock()
    moveBall(BALL.dir.x, BALL.dir.y)
    if checkPaddleCollision() then
      BALL.dir.x = (BALL.dir.x == 1 and -1 or 1)
      moveBall(BALL.dir.x, 0)
      ballMoved = false
    elseif checkWallCollision() then
      BALL.dir.y = (BALL.dir.y == 1 and -1 or 1)
      moveBall((BALL.dir.x == 1 and -1 or 1), BALL.dir.y)
      ballMoved = false
    elseif checkGoalCollision() then
      setupBall()
      setupPaddles()
    end
  end

  local paddleMoved = false
  if keyPressed then
    for i = 1, 2 do
      if os.clock() - PLAYER_PADDLES[i].lastMove >= 0.3 then
        PLAYER_PADDLES[i].lastMove = os.clock()
        local moveAmount = keyPressed == PLAYER_KEYS[i].up and -1 or (keyPressed == PLAYER_KEYS[i].down and 1 or 0)
        PLAYER_PADDLES[i].y = PLAYER_PADDLES[i].y + moveAmount
        paddleMoved = true
        break
      end
    end
    keyPressed = nil -- we have processed the key, remove it so we don't process it again
  end

  renderRequired = (paddleMoved or ballMoved)
end

local function render()
  if not renderRequired then return end

  -- clear the screen
  term.setBackgroundColor(colors.black)
  term.clear()

  -- draw the middle line
  term.setTextColor(colors.white)
  for i = 1, sh do
    term.setCursorPos(math.ceil(sw / 2), i)
    write('|')
  end


  -- render our ball
  term.setCursorPos(BALL.pos.x, BALL.pos.y)
  term.setBackgroundColor(colors.white)
  write('O')

  -- render the paddles
  for i = 1, 2 do
    for y = 0, PADDLE_HEIGHT - 1 do
      term.setCursorPos(PLAYER_PADDLES[i].x, PLAYER_PADDLES[i].y + y)
      write('#')
    end
  end

  renderRequired = false
end

local function main(argv, argc)
  setupBall()
  setupPaddles()
  render()

  while true do
    processInput()
    update()
    render()
  end

  return true
end

-- create a terminal object with a non-advanced computer safe version of setting colors
local termObj = {
  setTextColor = function(n) if term.isColor and term.isColor() then local ok, err = pcall(term.native.setTextColor , n) if not ok then error(err, 2) end end end,
  setBackgroundColor = function(n) if term.isColor and term.isColor() then local ok, err = pcall(term.native.setBackgroundColor , n) if not ok then error(err, 2) end end end
}
-- also override the English spelling of the colour functions
termObj.setTextColour = termObj.setTextColor
termObj.setBackgroundColour = termObj.setBackgroundColor

-- make the terminal object refer to the native terminal for every other function
termObj.__index = term.native
setmetatable(termObj, termObj)

-- redirect the terminal to the new object
term.redirect(termObj)

-- run the program
local ok, err = pcall(main, #{...}, {...})

-- catch-all
if not ok and err ~= 'Terminated' then
  clear()
  print('Error in runtime!')
  print(err)
  sleep(5)
end

-- print thank you message
clear()
cwriteWithFormat('&4Thank you for playing CCPong v1.0', 1)
cwriteWithFormat('&4By &8TheOriginal&3BIT\n', 2)

-- restore the default terminal object
term.restore()