-- tilemap test 03

local sti = require "sti"

local scroll_type

function love.load()
  -- init

  -- set filter
  love.graphics.setDefaultFilter("nearest", "nearest")

  -- set canvas size
  scr_w = 640
  scr_h = 480
  canvas = love.graphics.newCanvas(scr_w, scr_h)

  -- get window width and height
  wdw_w, wdw_h = love.graphics.getDimensions()

  scr_scale = math.min((wdw_w / scr_w), (wdw_h / scr_h))
  scr_ofsx = (wdw_w - (scr_w * scr_scale)) / 2
  scr_ofsy = (wdw_h - (scr_h * scr_scale)) / 2

  -- load tilemap
  map = sti("mecha_bg_map.lua")

  map.getGidByPixel = function(self, x, y, layerindex)
    local tilex, tiley = self:convertPixelToTile(math.floor(x), math.floor(y))
    tilex = math.floor(tilex)
    tiley = math.floor(tiley)
    local layer = map.layers[layerindex]
    local tilew = layer.width
    local tileh = layer.height
    local gid = -2
    if tilex >= 0 and tiley >= 0 and tilex < tilew and tiley < tileh then
      local tile = layer.data[tiley + 1][tilex + 1]
      if tile == nil then
        gid = -1
      else
        gid = tile.gid
      end
    end
    return gid
  end

  scroll_type = 2

  layers = {}
  for i,layer in ipairs(map.layers) do
    -- print(i, layer.name)
    layers[i] = layer
  end

  -- init bg position
  tx_start = 0
  ty_start = 0
  tx = tx_start
  ty = ty_start

  gid = 0

  -- framerate steady
  min_dt = 1 / 60
  next_time = love.timer.getTime()
end

function love.update(dt)
  -- update
  next_time = next_time + min_dt

  map:update(dt)

  -- keyboard check
  local speed = 160 * dt
  local kd = love.keyboard.isDown
  if kd("left") or kd("a") then
    tx = tx - speed
  elseif kd("right") or kd("d") then
    tx = tx + speed
  end
  if kd("up") or kd("w") then
    ty = ty - speed
  elseif kd("down") or kd("s") then
    ty = ty + speed
  end
  if kd("r") then
    tx = tx_start
    ty = ty_start
  end

  if scroll_type == 0 then
    map.layers["bg_a"].x = 0
    map.layers["bg_a"].y = 0
    map.layers["bg_b"].x = 0
    map.layers["bg_b"].y = 0
  elseif scroll_type == 1 then
    layers[2].x = -tx
    layers[2].y = -ty
    layers[1].x = -tx / 2
    layers[1].y = -ty / 2
  elseif scroll_type == 2 then
    map.layers["bg_a"].x = -tx
    map.layers["bg_a"].y = -ty
    map.layers["bg_b"].x = -tx / 4
    map.layers["bg_b"].y = -ty / 4
  end

  -- get mouse position
  local mx, my = love.mouse.getPosition()
  mx = (mx - scr_ofsx) / scr_scale
  my = (my - scr_ofsy) / scr_scale

  -- get tile gid
  mx = mx + tx
  my = my + ty
  gid = map:getGidByPixel(mx, my, "bg_a")
end

function love.draw()

  -- set canvas
  love.graphics.setCanvas(canvas)

  -- draw BG color
  love.graphics.setColor(0, 0, 0)
  love.graphics.rectangle("fill", 0, 0, scr_w, scr_h)

  -- draw tilemap BG
  love.graphics.setColor(255, 255, 255)
  if scroll_type == 0 then
    map:draw(-tx, -ty)
  elseif scroll_type == 1 then
    for i, layer in ipairs(layers) do
      map:drawLayer(layer)
    end
  elseif scroll_type == 2 then
    map:draw()
  end

  -- unset canvas
  love.graphics.setCanvas()

  -- draw canvas to window
  love.graphics.setColor(255, 255, 255)
  love.graphics.draw(canvas, scr_ofsx, scr_ofsy, 0, scr_scale, scr_scale)

  love.graphics.print("FPS: "..tostring(love.timer.getFPS()), 10, 10)
  love.graphics.print("tx = "..tostring(tx), 10, 40)
  love.graphics.print("ty = "..tostring(ty), 10, 60)
  love.graphics.print("C : scroll type = "..tostring(scroll_type), 10, 80)
  love.graphics.print("R : reset", 10, 100)
  love.graphics.print("ESC : exit", 10, 120)
  love.graphics.print("gid = "..tostring(gid), 10, 160, 0, 2.0, 2.0)

  if love.system.getOS() == "Windows" then
    -- wait
    local cur_time = love.timer.getTime()
    if next_time <= cur_time then
      next_time = cur_time
    else
      love.timer.sleep(next_time - cur_time)
    end
  end
end

function love.keypressed(key, isrepeat)
  -- ESC to exit
  if key == "escape" then
    love.event.quit()
  end
  if key == "c" then
    scroll_type = (scroll_type + 1) % 3
  end
end