Columns

local w,h = term.getSize()

tray = {
w = 12;
h = 12;
}
xoff = math.floor(w/2) - tray.w/2
yoff = 5
gcombo = 1

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 = 0.25

local piece,npiece = nil,nil
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]
    piece[3] = piece[2]
    piece[2] = piece[1]
    piece[1] = temp
  else
    temp = piece[1]
    piece[1] = piece[2]
    piece[2] = piece[3]
    piece[3] = temp
  end
end

function makePiece()
  piece = npiece
  npiece = {x = tray.w/2, y = -2}
  for i=1,3 do
    npiece[i] = avcols[math.random(1,#avcols)]
  end
  if not piece then makePiece() end
end

function checkMatches(clist)
  matchlist = {}
  ccol,crun = nil, 0
  term.setTextColour(colours.white)

  for _,v in pairs(clist) do
    local col = tray[v[2]][v[1]]
    local crun = 0
    --horizontal
    for x=math.max(v[1]-2,0),math.min(v[1]+2,tray.w) do
      if tray[v[2]][x] == col then
        crun = crun + 1
        if crun == 3 then for nx=x-2,x do
          table.insert(matchlist, {nx,v[2]}) end
        elseif crun > 3 then table.insert(matchlist, {x,v[2]}) end
      else crun = 0 end
    end
    --vertical
    crun = 0
    for y=math.max(v[2]-2,1),math.min(v[2]+2,tray.h) do
      assert(tray[y],y)
      if tray[y][v[1]] == col then
        crun = crun + 1
        if crun == 3 then for ny=y-2,y do
          table.insert(matchlist, {v[1],ny}) end
        elseif crun > 3 then table.insert(matchlist, {v[1],y}) end
      else crun = 0 end
    end
    --diagonal right
    crun = 0
    for i=-2,2 do
      if tray[v[2]+i] and tray[v[2]+i][v[1]+i] == col then
        crun = crun + 1
        if crun == 3 then for j=i-2,i do
          table.insert(matchlist, {v[1]+j, v[2]+j}) end
        elseif crun > 3 then table.insert(matchlist, {v[1]+i,v[2]+i}) end
      else crun = 0 end
    end
    crun = 0
    --diagonal left
    for i=-2,2 do
      if tray[v[2]-i] and tray[v[2]-i][v[1]+i] == col then
        crun = crun + 1
        if crun == 3 then for j=i-2,i do
          table.insert(matchlist, {v[1]+j,v[2]-j}) end
        elseif crun > 3 then table.insert(matchlist, {v[1]+i,v[2]-i}) end
      else crun = 0 end
    end
  end

  --A display then we delete
  if #matchlist == 0 then return false end
  for i=1,2 do
    draw()
    for _,v in pairs(matchlist) do
      assert(tray[v[2]] and tray[v[2]][v[1]], v[1]..","..v[2])
      term.setCursorPos(xoff + v[1], yoff + v[2])
      term.setBackgroundColour(tray[v[2]][v[1]])
      term.setTextColour(colours.black)
      if i==1 then term.write("*")
      else term.write("#") end
    end
    sleep(tlength/2)
  end
  for _,v in ipairs(matchlist) do
    tray[v[2]][v[1]] = nil
    score = score + (10 * gcombo)
  end
  return #matchlist > 0
end

function runGravity()
  local mlist = nil
  local runAgain = false
  repeat
    local tlist = {}
    runAgain = false
    for y=tray.h-1,1,-1 do
      for x=1,tray.w do
        if tray[y][x] and not tray[y+1][x] then
          tray[y+1][x] = tray[y][x]
          tray[y][x] = nil
          table.insert(tlist,{x,y+1})
          runAgain = true
        end
      end
    end
    draw()
    if runAgain then
      sleep(tlength/2)
      mlist = tlist
    end
    tlist = {}
  until not runAgain
  return mlist
end

function drop()
  gcombo = 1
  local mlist = {}
  for i=1,3 do
    tray[piece.y+i-1][piece.x] = piece[i]
    table.insert(mlist, {piece.x, piece.y +i -1})
  end
  makePiece()
  while true do
    if not checkMatches(mlist) then break end
    mlist = runGravity()
    gcombo = gcombo + 1
    if not mlist then break end
  end
end

function canMove(dir)
  return (not tray[piece.y] or tray[piece.y][piece.x+dir] == nil) and
       (not tray[piece.y+1] or tray[piece.y+1][piece.x+dir] == nil) and
       (not tray[piece.y+2] or tray[piece.y+2][piece.x+dir] == nil)
end

function input()
  gtimer = os.startTimer(tlength)
  while true do
    local id,p = os.pullEvent()
    if id == "timer" then
      if p == gtimer then
        if piece.y + 2 >= tray.h or tray[piece.y + 3][piece.x] ~= nil then
          if piece.y < 1 then break end
          drop()
        elseif tray[piece.y + 3][piece.x] == nil then
          piece.y = piece.y + 1
        end
        gtimer = os.startTimer(tlength)
      end
    elseif id == "key" then
      if p == keys.left and gtimer and piece.x > 1 and
        canMove(-1) then piece.x = piece.x - 1
      elseif p == keys.right and gtimer and piece.x < tray.w and
        canMove(1) then piece.x = piece.x + 1
      elseif p == keys.up and gtimer then rotate(1)
      elseif p == keys.down and gtimer then rotate(-1)
      elseif p == keys.space then
        while piece.y + 2 < tray.h and tray[piece.y + 3][piece.x] == nil do
          piece.y = piece.y + 1
        end
        if piece.y < 1 then break end
        drop()
        gtimer = os.startTimer(tlength)
      elseif p == keys.q then os.pullEvent() break
      elseif p == keys.p then
        if gtimer then gtimer = nil
        else gtimer = os.startTimer(tlength) end
      end
    end
    draw()
  end
end

function drawNext(npiece,tray)
  term.setCursorPos(xoff+tray.w+1,yoff+1)
  term.setBackgroundColour(colours.grey)
  term.write(string.rep(" ", 5))
  term.setCursorPos(xoff+tray.w+1,yoff+5)
  term.write(string.rep(" ", 5))
  for i=1,3 do
    term.setCursorPos(xoff+tray.w+2,yoff+i+1)
    term.setBackgroundColour(colours.black)
    term.write(string.rep(" ", 3))
    term.setBackgroundColour(colours.grey)
    term.write(" ")
  end
  for i=1,#npiece do
    term.setCursorPos(xoff + tray.w + 3, yoff + i+1)
    term.setBackgroundColour(npiece[i])
    term.write(" ")
  end
end

function draw()
  term.setCursorBlink(false)
  --There's an offset error I'm... too tired to fix
  term.setCursorPos(xoff,yoff+tray.h+1)
  term.setBackgroundColour(colours.grey)
  term.write(string.rep(" ",tray.w+2))
  term.setBackgroundColour(colours.lightGrey)
  for y=yoff-2,yoff do
    term.setCursorPos(xoff,y)
    term.write(string.rep(" ", tray.w + 2))
  end

  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 - 1)
    term.setBackgroundColour(piece[i])
    term.write(" ")
  end
  term.setCursorPos(xoff + 1,yoff + tray.h + 1)
  term.setBackgroundColour(colours.grey)
  term.setTextColour(colours.white)
  term.write("Score: "..score)
  drawNext(npiece, tray)

  term.setBackgroundColour(colours.lightGrey)
  term.setTextColour(colours.red)
  local txt = "Column Drop"
  term.setCursorPos(w/2-#txt/2,2)
  term.write(txt)
end

term.setBackgroundColour(colours.lightGrey)
shell.run("clear")
init()
makePiece()
draw()
input()
term.setBackgroundColour(colours.black)
shell.run("clear")