columns

local w,h = term.getSize()
local tray = {
  w = 12;
  h = 18;
}
local xoff,yoff = w/2 - tray.w/2, 0
local avcols = {
  colours.orange, colours.green, colours.blue,
  colours.red, colours.purple, colours.white
}
local cnum = 3
local score = 0

local gtimer = nil
local tlength = 1

local piece = { x = tray.w/2, y = -2}

function init()
  for y = 1,tray.h do
    tray[y] = {}
  end
end

function rotate(dir)
  local temp = nil
  if dir == -1 then
    temp = piece[3]
    for i=3,2,dir do piece[i-1] = piece[i] end
    piece[1] = temp
  else
    temp = piece[1]
    for i=1,2,dir do piece[i+1] = piece[i] end
    piece[3] = temp
  end
end

function makePiece()
  for i=1,3 do
    piece[i] = avcols[math.random(1,#avcols)]
  end
  piece.x,piece.y = tray.w/2,-2
end

function checkMatches()
  matchlist = {}
  ccol,crun = nil, 0
  --Horizontal
  for y=tray.y,1,-1 do
    top = true
    ccol, crun = nil, 0
    for x=1,tray.w do
      if tray[y][x] then top = false end
      if tray[y][x] == ccol and tray[y][x] ~= nil then
        crun = crun + 1
        if crun == 3 then
          for i=x-2,x do table.insert(matchlist, {i,y}) end
        elseif crun > 3 then
          table.insert(matchlist, {x,y})
        end
      else ccol,crun = tray[y][x],0 end
    end
  end
  --Vertical
  for x=1,tray.x do
    ccol, crun = nil, 0
    for y=tray.y,1 do
      if tray[y][x] == nil then break
      elseif tray[y][x] == ccol then
        crun = crun + 1
        if crun == 3 then
          for i=y-2,y do table.insert(matchlist,{i,y}) end
        elseif crun > 3 then
          table.insert(matchlist, {x,y})
        end
      else ccol,crun = tray[y][x],0 end
    end
  end
  for _,v in ipairs(matchlist) do
    tray[v[2]][v[1]] = nil
    score = score + 1
  end
  return #matchlist > 0
end

function runGravity()
  local runAgain = false
  repeat
    runAgain = false
    for y=tray.y-1,1,-1 do
      local top = true
      for x=1,tray.x do
        if tray[y][x] then
          top = false
          if not tray[y-1][x] then
            tray[y-1][x] = tray[y][x]
            tray[y][x] = nil
            runAgain = true
          end
        end
      end
      if top then break end
    end
    sleep(tlength)
  until not runAgain
end

function input()
  gtimer = os.startTimer(tlength)
  while true do
    local id,p = os.pullEvent()
    term.setCursorPos(1,1)
    term.write(id..":"..p.."("..gtimer..")")
    if id == "timer" then
      if p == gtimer then
        if piece.y + 3 > tray.h or tray[piece.y + 3][piece.x] ~= nil then
          for i=1,3 do tray[y+i-1][piece.x] = piece[i] end
          makePiece()
        elseif tray[piece.y + 3][piece.x] == nil then
          piece.y = piece.y + 1
          gtimer = os.startTimer(tlength)
        else
          for i=1,3 do tray[y+i-1][piece.x] = piece[i] end
          while true do if not checkMatches() then break end
            runGravity()
          end
          makePiece()
        end
      end
    elseif id == "key" then
      if p == keys.left and piece.x > 0 then piece.x = piece.x - 1
      elseif p == keys.right and piece.x < tray.w then piece.x = piece.x + 1
      elseif p == keys.up then rotate(-1)
      elseif p == keys.down then rotate(1)
      elseif p == keys.q then break end
    end
    draw()
  end
end

function draw()
  for y=1, tray.h do
    term.setBackgroundColour(colours.grey)
    term.setCursorPos(xoff,y+yoff)
    term.write(" ")
    term.setCursorPos(xoff + tray.w + 1, y+yoff)
    term.write(" ")
    for x=1, tray.w do
      term.setCursorPos(x+xoff,y+yoff)
      term.setBackgroundColour(tray[y][x] or colours.black)
      term.write(" ")
    end
  end
  for i=1,#piece do
    term.setCursorPos(xoff + piece.x, yoff + piece.y + i)
    term.setBackgroundColour(piece[i])
    term.write(" ")
  end
end

init()
draw()
makePiece()
input()