-- SPDX-FileCopyrightText: 2017 Daniel Ratcliffe
--
-- SPDX-License-Identifier: LicenseRef-CCPL

--[[
Falling - Based on Tetris by Alexey Pajitnov
This version written by Gopher, at the request of Dan200, for
ComputerCraft v1.6. No particular rights are reserved.
--]]

local function colorass(c, bw)
  return term.isColor() and c or bw
end

local block_s1 = {
    {
      { 1, 0, 0, 0 },
      { 1, 1, 0, 0 },
      { 0, 1, 0, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 0, 0, 0, 0 },
      { 0, 1, 1, 0 },
      { 1, 1, 0, 0 },
      { 0, 0, 0, 0 },
    },
    ch = colorass("  ", "{}"),
    fg = colorass(colors.blue, colors.black),
    bg = colorass(colors.cyan, colors.white),
  }
local block_s2 = {
    {
      { 0, 1, 0, 0 },
      { 1, 1, 0, 0 },
      { 1, 0, 0, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 0, 0, 0, 0 },
      { 1, 1, 0, 0 },
      { 0, 1, 1, 0 },
      { 0, 0, 0, 0 },
    },
    ch = colorass("  ", "{}"),
    fg = colorass(colors.green, colors.black),
    bg = colorass(colors.lime, colors.white),
  }
local block_line = {
    {
      { 0, 1, 0, 0 },
      { 0, 1, 0, 0 },
      { 0, 1, 0, 0 },
      { 0, 1, 0, 0 },
    },
    {
      { 0, 0, 0, 0 },
      { 1, 1, 1, 1 },
      { 0, 0, 0, 0 },
      { 0, 0, 0, 0 },
    },
    ch = colorass("  ", "[]"),
    fg = colorass(colors.pink, colors.black),
    bg = colorass(colors.red, colors.white),
  }
local block_square = {
    {
      { 1, 1, 0, 0 },
      { 1, 1, 0, 0 },
      { 0, 0, 0, 0 },
      { 0, 0, 0, 0 },
    },
    ch = colorass("  ", "[]"),
    fg = colorass(colors.lightBlue, colors.black),
    bg = colorass(colors.blue, colors.white),
  }
local block_L1 = {
    {
      { 1, 1, 0, 0 },
      { 0, 1, 0, 0 },
      { 0, 1, 0, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 0, 0, 0, 0 },
      { 1, 1, 1, 0 },
      { 1, 0, 0, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 0, 1, 0, 0 },
      { 0, 1, 0, 0 },
      { 0, 1, 1, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 0, 0, 1, 0 },
      { 1, 1, 1, 0 },
      { 0, 0, 0, 0 },
      { 0, 0, 0, 0 },
    },
    ch = colorass("  ", "()"),
    fg = colorass(colors.orange, colors.black),
    bg = colorass(colors.yellow, colors.white),
  }
local block_L2 = {
    {
      { 0, 1, 0, 0 },
      { 0, 1, 0, 0 },
      { 1, 1, 0, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 0, 0, 0, 0 },
      { 1, 1, 1, 0 },
      { 0, 0, 1, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 0, 1, 1, 0 },
      { 0, 1, 0, 0 },
      { 0, 1, 0, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 1, 0, 0, 0 },
      { 1, 1, 1, 0 },
      { 0, 0, 0, 0 },
      { 0, 0, 0, 0 },
    },
    ch = colorass("  ", "()"),
    fg = colorass(colors.brown, colors.black),
    bg = colorass(colors.orange, colors.white),
  }
local block_T = {
    {
      { 0, 1, 0, 0 },
      { 1, 1, 0, 0 },
      { 0, 1, 0, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 0, 0, 0, 0 },
      { 1, 1, 1, 0 },
      { 0, 1, 0, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 0, 1, 0, 0 },
      { 0, 1, 1, 0 },
      { 0, 1, 0, 0 },
      { 0, 0, 0, 0 },
    },
    {
      { 0, 1, 0, 0 },
      { 1, 1, 1, 0 },
      { 0, 0, 0, 0 },
      { 0, 0, 0, 0 },
    },
    ch = colorass("  ", "<>"),
    fg = colorass(colors.cyan, colors.black),
    bg = colorass(colors.purple, colors.white),
  }

local blocks = { block_line, block_square, block_s1, block_s2, block_L1, block_L2, block_T }

local points = { 4, 10, 30, 120 }

local function lpad(text, amt)
  text = tostring(text)
  return string.rep(" ", amt - #text) .. text
end

local width, height = term.getSize()

if height < 19 or width < 26 then
  print("Your screen is too small to play :(")
  return
end


local speedsByLevel = {
  1.2,
  1.0,
   .8,
   .65,
   .5,
   .4,
   .3,
   .25,
   .2,
   .15,
   .1,
   .05, }

local level = 1

local function playGame()
  local score = 0
  local lines = 0
  local initialLevel = level
  local next = blocks[math.random(1, #blocks)]

  local pit = {}


  local heightAdjust = 0

  if height <= 19 then
    heightAdjust = 1
  end



  local function drawScreen()
    term.setTextColor(colors.white)
    term.setBackgroundColor(colors.black)
    term.clear()

    term.setTextColor(colors.black)
    term.setBackgroundColor(colorass(colors.lightGray, colors.white))
    term.setCursorPos(22, 2)
    term.write("Score") --score
    term.setCursorPos(22, 5)
    term.write("Level")  --level
    term.setCursorPos(22, 8)
    term.write("Lines")  --lines
    term.setCursorPos(22, 12)
    term.write("Next") --next

    term.setCursorPos(21, 1)
    term.write("      ")
    term.setCursorPos(21, 2)
    term.write(" ") --score
    term.setCursorPos(21, 3)
    term.write(" ")
    term.setCursorPos(21, 4)
    term.write("      ")
    term.setCursorPos(21, 5)
    term.write(" ")  --level
    term.setCursorPos(21, 6)
    term.write(" ")
    term.setCursorPos(21, 7)
    term.write("      ")
    term.setCursorPos(21, 8)
    term.write(" ")  --lines
    term.setCursorPos(21, 9)
    term.write(" ")
    term.setCursorPos(21, 10)
    term.write("      ")
    term.setCursorPos(21, 11)
    term.write("      ")
    term.setCursorPos(21, 12)
    term.write(" ") --next
    term.setCursorPos(26, 12)
    term.write(" ") --next
    term.setCursorPos(21, 13)
    term.write("      ")
    term.setCursorPos(21, 14)
    term.write(" ")
    term.setCursorPos(21, 15)
    term.write(" ")
    term.setCursorPos(21, 16)
    term.write(" ")
    term.setCursorPos(21, 17)
    term.write(" ")
    term.setCursorPos(21, 18)
    term.write(" ")
    term.setCursorPos(21, 19)
    term.write("      ")
    term.setCursorPos(21, 20)
    term.write("      ")
  end

  local function updateNumbers()
    term.setTextColor(colors.white)
    term.setBackgroundColor(colors.black)

    term.setCursorPos(22, 3)
    term.write(lpad(score, 5)) --score
    term.setCursorPos(22, 6)
    term.write(lpad(level, 5))  --level
    term.setCursorPos(22, 9)
    term.write(lpad(lines, 5))  --lines
  end

  local function drawBlockAt(block, xp, yp, rot)
    term.setTextColor(block.fg)
    term.setBackgroundColor(block.bg)
    for y = 1, 4 do
      for x = 1, 4 do
        if block[rot][y][x] == 1 then
          term.setCursorPos((xp + x) * 2 - 3, yp + y - 1 - heightAdjust)
          term.write(block.ch)
        end
      end
    end
  end

  local function eraseBlockAt(block, xp, yp, rot)
    term.setTextColor(colors.white)
    term.setBackgroundColor(colors.black)
    for y = 1, 4 do
      for x = 1, 4 do
        if block[rot][y][x] == 1 then
          term.setCursorPos((xp + x) * 2 - 3, yp + y - 1 - heightAdjust)
          term.write("  ")
        end
      end
    end
  end

  local function testBlockAt(block, xp, yp, rot)
    for y = 1, 4 do
      local ty = yp + y - 1
      for x = 1, 4 do
        local tx = xp + x - 1
        if block[rot][y][x] == 1 then
          if tx > 10 or tx < 1 or ty > 20 or pit[ty][tx] ~= 0 then
            return true
          end
        end
      end
    end
  end

  local function pitBlock(block, xp, yp, rot)
    for y = 1, 4 do
      for x = 1, 4 do
        if block[rot][y][x] == 1 then
          pit[yp + y - 1][xp + x - 1] = block
        end
      end
    end
  end


  local function clearPit()
    for row = 1, 20 do
      pit[row] = {}
      for col = 1, 10 do
        pit[row][col] = 0
      end
    end
  end



  drawScreen()
  updateNumbers()

  --declare & init the pit
  clearPit()



  local halt = false
  local dropSpeed = speedsByLevel[math.min(level, 12)]


  local curBlock = next
  next = blocks[math.random(1, 7)]

  local curX, curY, curRot = 4, 1, 1
  local dropTimer = os.startTimer(dropSpeed)

  drawBlockAt(next, 11.5, 15 + heightAdjust, 1)
  drawBlockAt(curBlock, curX, curY, curRot)

  local function redrawPit()
    for r = 1 + heightAdjust, 20 do
      term.setCursorPos(1, r - heightAdjust)
      for c = 1, 10 do
        if pit[r][c] == 0 then
          term.setTextColor(colors.black)
          term.setBackgroundColor(colors.black)
          term.write("  ")
        else
          term.setTextColor(pit[r][c].fg)
          term.setBackgroundColor(pit[r][c].bg)
          term.write(pit[r][c].ch)
        end
      end
    end
  end

  local function hidePit()
    for r = 1 + heightAdjust, 20 do
      term.setCursorPos(1, r - heightAdjust)
      term.setTextColor(colors.black)
      term.setBackgroundColor(colors.black)
      term.write("                    ")
    end
  end

  local function msgBox(message)
    local x = math.floor((17 - #message) / 2)
    term.setBackgroundColor(colorass(colors.lightGray, colors.white))
    term.setTextColor(colors.black)
    term.setCursorPos(x, 9)
    term.write("+" .. string.rep("-", #message + 2) .. "+")
    term.setCursorPos(x, 10)
    term.write("|")
    term.setCursorPos(x + #message + 3, 10)
    term.write("|")
    term.setCursorPos(x, 11)
    term.write("+" .. string.rep("-", #message + 2) .. "+")
    term.setTextColor(colors.white)
    term.setBackgroundColor(colors.black)
    term.setCursorPos(x + 1, 10)
    term.write(" " .. message .. " ")
  end

  local function clearRows()
    local rows = {}
    for r = 1, 20 do
      local count = 0
      for c = 1, 10 do
        if pit[r][c] ~= 0 then
          count = count + 1
        else
          break
        end
      end
      if count == 10 then
        rows[#rows + 1] = r
      end
    end

    if #rows > 0 then
      for _ = 1, 4 do
        sleep(.1)
        for r = 1, #rows do
          r = rows[r]
          term.setCursorPos(1, r - heightAdjust)
          for c = 1, 10 do
            term.setTextColor(pit[r][c].bg)
            term.setBackgroundColor(pit[r][c].fg)
            term.write(pit[r][c].ch)
          end
        end
        sleep(.1)
        for r = 1, #rows do
          r = rows[r]
          term.setCursorPos(1, r - heightAdjust)
          for c = 1, 10 do
            term.setTextColor(pit[r][c].fg)
            term.setBackgroundColor(pit[r][c].bg)
            term.write(pit[r][c].ch)
          end
        end
      end
      --now remove the rows and drop everything else
      term.setBackgroundColor(colors.black)
      for r = 1, #rows do
        r = rows[r]
        term.setCursorPos(1, r - heightAdjust)
        term.write("                    ")
      end
      sleep(.25)
      for r = 1, #rows do
        table.remove(pit, rows[r])
        table.insert(pit, 1, { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 })
      end
      redrawPit()
      lines = lines + #rows
      score = score + points[#rows] * math.min(level, 20)
      level = math.floor(lines / 10) + initialLevel
      dropSpeed = speedsByLevel[math.min(level, 12)]
      updateNumbers()
    end
    sleep(.25)
  end

  local function blockFall()
    if testBlockAt(curBlock, curX, curY + 1, curRot) then
      pitBlock(curBlock, curX, curY, curRot)
      --detect rows that clear
      clearRows()

      curBlock = next
      curX = 4
      curY = 1
      curRot = 1
      if testBlockAt(curBlock, curX, curY, curRot) then
        halt = true
      end
      drawBlockAt(curBlock, curX, curY, curRot)
      eraseBlockAt(next, 11.5, 15 + heightAdjust, 1)
      next = blocks[math.random(1, 7)]
      drawBlockAt(next, 11.5, 15 + heightAdjust, 1)
      return true
    else
      eraseBlockAt(curBlock, curX, curY, curRot)
      curY = curY + 1
      drawBlockAt(curBlock, curX, curY, curRot)
      return false
    end
  end


  while not halt do
    local e = { os.pullEvent() }
    if e[1] == "timer" then
      if e[2] == dropTimer then
        blockFall()
        dropTimer = os.startTimer(dropSpeed)
      end
    elseif e[1] == "key" then
      local key = e[2]
      local dx, dy, dr = 0, 0, 0
      if key == keys.left or key == keys.a then
        dx = -1
      elseif key == keys.right or key == keys.d then
        dx = 1
      elseif key == keys.up or key == keys.w then
        dr = 1
      elseif key == keys.down or key == keys.s then
        while not blockFall() do end
        dropTimer = os.startTimer(dropSpeed)
      elseif key == keys.space then
        hidePit()
        msgBox("Paused")
        while ({ os.pullEvent("key") })[2] ~= keys.space do end
        redrawPit()
        drawBlockAt(curBlock, curX, curY, curRot)
        dropTimer = os.startTimer(dropSpeed)
      end
      if dx + dr ~= 0 then
        if not testBlockAt(curBlock, curX + dx, curY + dy, dr > 0 and curRot % #curBlock + dr or curRot) then
          eraseBlockAt(curBlock, curX, curY, curRot)
          curX = curX + dx
          curY = curY + dy
          curRot = dr == 0 and curRot or curRot % #curBlock + dr
          drawBlockAt(curBlock, curX, curY, curRot)
        end
      end
    elseif e[1] == "term_resize" then
      local _, h = term.getSize()
      if h == 20 then
        heightAdjust = 0
      else
        heightAdjust = 1
      end
      redrawPit()
      drawBlockAt(curBlock, curX, curY, curRot)
    end
  end

  msgBox("Game Over!")
  while true do
    local _, k = os.pullEvent("key")
    if k == keys.space or k == keys.enter or k == keys.numPadEnter then
      break
    end
  end

  level = math.min(level, 9)
end


local selected = 1
local playersDetected = false

local function drawMenu()
  term.setBackgroundColor(colors.black)
  term.setTextColor(colorass(colors.red, colors.white))
  term.clear()

  local cx, cy = math.floor(width / 2), math.floor(height / 2)

  term.setCursorPos(cx - 6, cy - 2)
  term.write("F A L L I N G")

  if playersDetected then
    if selected == 0 then
      term.setTextColor(colorass(colors.blue, colors.black))
      term.setBackgroundColor(colorass(colors.gray, colors.white))
    else
      term.setTextColor(colorass(colors.lightBlue, colors.white))
      term.setBackgroundColor(colors.black)
    end
    term.setCursorPos(cx - 12, cy)
    term.write(" Play head-to-head game! ")
  end

  term.setCursorPos(cx - 10, cy + 1)
  if selected == 1 then
    term.setTextColor(colorass(colors.blue, colors.black))
    term.setBackgroundColor(colorass(colors.lightGray, colors.white))
  else
    term.setTextColor(colorass(colors.lightBlue, colors.white))
    term.setBackgroundColor(colors.black)
  end
  term.write(" Play from level: <" .. level .. "> ")

  term.setCursorPos(cx - 3, cy + 3)
  if selected == 2 then
    term.setTextColor(colorass(colors.blue, colors.black))
    term.setBackgroundColor(colorass(colors.lightGray, colors.white))
  else
    term.setTextColor(colorass(colors.lightBlue, colors.white))
    term.setBackgroundColor(colors.black)
  end
  term.write(" Quit ")
end


local function runMenu()
  drawMenu()

  while true do
    local event = { os.pullEvent() }
    if event[1] == "key" then
      local key = event[2]
      if key == keys.right or key == keys.d and selected == 1 then
        level = math.min(level + 1, 9)
        drawMenu()
      elseif key == keys.left or key == keys.a and selected == 1 then
        level = math.max(level - 1, 1)
        drawMenu()
      elseif key >= keys.one and key <= keys.nine and selected == 1 then
        level = key - keys.one + 1
        drawMenu()
      elseif key == keys.up or key == keys.w then
        selected = selected - 1
        if selected == 0 then
          selected = 2
        end
        drawMenu()
      elseif key == keys.down or key == keys.s then
        selected = selected % 2 + 1
        drawMenu()
      elseif key == keys.enter or key == keys.numPadEnter or key == keys.space then
        break --begin play!
      end
    end
  end
end

while true do
  runMenu()
  if selected == 2 then
    break
  end

  playGame()
end


term.setTextColor(colors.white)
term.setBackgroundColor(colors.black)
term.clear()
term.setCursorPos(1, 1)