local sti = require("sti")
local inspect = require("inspect")

love.graphics.setDefaultFilter("nearest", "nearest")

local game = {
   SCREEN_WIDTH=320,
   SCREEN_HEIGHT=200,
   TILE_SIZE=16,
   -- NOTE: playfield dimensions in tiles
   PLAYFIELD_OFFSET_TOP=1.5,
   PLAYFIELD_WIDTH=20,
   PLAYFIELD_HEIGHT=10,
   VEHICLE_SPEED=10,
   FLOATDEV_SPEED=8,
   playFieldTiles={},
   map=sti("map.lua"),
   entities={
	  vehicles={},
	  floatdevs={},
   },
   hazards={},
   drawGrid=true,
}

function t2p(tileDim)
   return tileDim*game.TILE_SIZE
end

function tilePos2Pixels(tilePos)
   return t2p(tilePos.x - 1), t2p(tilePos.y - 1)
end

function screenPixelToTilePos(pixelPos)
   return {
	  x=math.floor(pixelPos.x/game.TILE_SIZE + 1),
	  y=math.floor((pixelPos.y + t2p(game.PLAYFIELD_OFFSET_TOP))/game.TILE_SIZE)
   }
end


local player = {
   pos={x=t2p(0), y=t2p(0)},
   turtlePos={x=t2p(0), y=t2p(1)},
   turtleHit=false,
   lives=3,
   turtles=3,
   dead=false,
   deadTimer=2,
   float_speed=0,
}

function resetPlayer()
   player.pos = {x=t2p(0), y=t2p(0)}
   player.dead = false
   player.turtleHit = false
   player.turtlePos = {x=t2p(0), y=t2p(1)}
end

function love.load()
   local desktop_width, desktop_height = love.window.getDesktopDimensions()
   game.scaleW = desktop_width / game.SCREEN_WIDTH
   game.scaleH = desktop_height / game.SCREEN_HEIGHT
   for i, layer in ipairs(game.map.layers) do
	  if layer.objects then
		 for j, mapObj in ipairs(layer.objects) do
			mapObj.visible = false
			local typekey = mapObj.type.."s"
			if game.entities[typekey] == nil then
			   game.entities[typekey] = {}
			end
			local entity = {
			   x=mapObj.x,
			   y=mapObj.y,
			   w=mapObj.width,
			   h=mapObj.height,
			   type=mapObj.type,
			}
			if entity.type == "floatdev" then
			   entity.speed = mapObj.properties.speed or game.FLOATDEV_SPEED
			end
			table.insert(game.entities[typekey], entity)
		 end
	  end
   end
end


function love.keyreleased(key)
   if player.dead or player.turtleHit then
	  return
   end
   local newPos = screenPixelToTilePos(player.pos)
   local oldPos = screenPixelToTilePos(player.pos)
   if key == "up" or key == "w" then
	  newPos.y = newPos.y - 1
   end
   if key == "down" or key == "s" then
	  newPos.y = newPos.y + 1
   end
   if key == "right" or key == "d" then
	  newPos.x = newPos.x + 1
   end
   if key == "left" or key == "a" then
	  newPos.x = newPos.x - 1
   end
   player.turtlePos.x = t2p(oldPos.x - 1)
   player.turtlePos.y = t2p(oldPos.y - 1)
   if newPos.x < 1 then
	  newPos.x = 1
   end
   if newPos.x > game.PLAYFIELD_WIDTH then
	  newPos.x = game.PLAYFIELD_WIDTH
   end
   if newPos.y < 1 then
	  newPos.y = 1
   end
   if newPos.y > game.PLAYFIELD_HEIGHT then
	  newPos.y = game.PLAYFIELD_HEIGHT
   end
   player.pos.x = t2p(newPos.x - 1)
   player.pos.y = t2p(newPos.y - 1)
end

function tilePos2Rect(tilePos)
   return {
	  x=t2p(tilePos.x - 1),
	  y=t2p(tilePos.y - 1),
	  w=game.TILE_SIZE,
	  h=game.TILE_SIZE,
   }
end

function rectanglesIntersect(rect1, rect2)
   return (rect1.x < rect2.x + rect2.w and
		 rect1.x + rect1.w > rect2.x and
		 rect1.y < rect2.y + rect2.h and
		 rect1.y + rect1.h > rect2.y)
end

function love.update(dt)
   if player.dead or player.turtleHit then
	  player.deadTimer = player.deadTimer - dt
	  if player.deadTimer <= 0 then
		 player.deadTimer = 2
		 resetPlayer()
	  end
   else
	  local playerRect = tilePos2Rect(screenPixelToTilePos(player.pos))
	  local turtleRect = tilePos2Rect(screenPixelToTilePos(player.turtlePos))
	  if player.float_speed ~= 0 then
		 player.pos.y = player.pos.y + player.float_speed*dt
		 player.turtlePos.y = player.turtlePos.y + player.float_speed*dt
	  end
	  for i, vehicle in ipairs(game.entities.vehicles) do
		 if rectanglesIntersect(playerRect, vehicle) then
			player.dead = true
			player.lives = player.lives - 1
		 end
		 if rectanglesIntersect(turtleRect, vehicle) then
			player.turtleHit = true
		 end
		 
		 vehicle.y = vehicle.y + game.VEHICLE_SPEED*dt
		 if vehicle.y > t2p(game.PLAYFIELD_HEIGHT) then
			vehicle.y = -vehicle.h
		 end
	  end
	  local was_floating = player.float_speed ~= 0
	  player.float_speed = 0
	  for i, floatdev in ipairs(game.entities.floatdevs) do
		 if player.float_speed == 0 and rectanglesIntersect(playerRect, floatdev) then
			if not was_floating then
			   if math.abs(player.pos.y - floatdev.y) > math.abs(player.pos.y - (floatdev.y + floatdev.h)) then
				  player.pos.y = floatdev.y
				  player.turtlePos.y = player.pos.y + game.TILE_SIZE*2
			   else
				  player.pos.y = floatdev.y + floatdev.h - game.TILE_SIZE
				  player.turtlePos.y = player.pos.y - game.TILE_SIZE
			   end
			end
			player.turtlePos.x = player.pos.x
			player.float_speed = floatdev.speed
		 end
		 floatdev.y = floatdev.y + floatdev.speed*dt
		 if floatdev.y > t2p(game.PLAYFIELD_HEIGHT) then
			floatdev.y = -floatdev.h
		 end
		 if floatdev.y + floatdev.h < t2p(0) then
			floatdev.y = t2p(game.PLAYFIELD_HEIGHT)
		 end
	  end
	  if player.float_speed == 0 then
		 for i, water in ipairs(game.entities.waters) do
			if not player.dead and rectanglesIntersect(playerRect, water) then
			   player.dead = true
			   player.lives = player.lives - 1
			end
		 end
		 if not player.dead and was_floating then
			player.turtlePos.x = player.pos.x
			player.turtlePos.y = player.pos.y - game.TILE_SIZE
			if player.turtlePos.y < t2p(0) then
			   player.turtlePos.y = player.pos.y + game.TILE_SIZE
			end
		 end
	  end
   end
end

function love.draw()
   love.graphics.setColor(1, 1, 1)
   game.map:draw(0, t2p(game.PLAYFIELD_OFFSET_TOP), game.scaleW, game.scaleH)
   love.graphics.push()
   -- <playfield>
   love.graphics.scale(game.scaleW, game.scaleH)
   love.graphics.translate(0, t2p(game.PLAYFIELD_OFFSET_TOP))
   if game.drawGrid then
	  love.graphics.setColor(0.4, 0.3, 0.1)
	  for i=0, game.PLAYFIELD_WIDTH do
		 love.graphics.line(t2p(i), 0, t2p(i), t2p(game.PLAYFIELD_HEIGHT))
	  end
	  for i=0, game.PLAYFIELD_HEIGHT do
		 love.graphics.line(0, t2p(i), t2p(game.PLAYFIELD_WIDTH), t2p(i))
	  end
   end
   love.graphics.setColor(0.9, 0.2, 0)
   for i, vehicle in ipairs(game.entities.vehicles) do
	  love.graphics.rectangle("fill", vehicle.x, vehicle.y, vehicle.w, vehicle.h)
   end
   love.graphics.setColor(0.8, 0.7, 0)
   for i, floatdev in ipairs(game.entities.floatdevs) do
	  love.graphics.rectangle("fill", floatdev.x, floatdev.y, floatdev.w, floatdev.h)
   end
   if player.dead then
	  love.graphics.setColor(0.8, 0.1, 0)
   else
	  love.graphics.setColor(0.9, 0.6, 0.1)
   end
   local x, y = player.pos.x, player.pos.y
   love.graphics.circle("fill", x + game.TILE_SIZE/2, y + game.TILE_SIZE/2, game.TILE_SIZE/2)
   love.graphics.setColor(0.2, 0.1, 0.1)
   love.graphics.circle("line", x + game.TILE_SIZE/2, y + game.TILE_SIZE/2, game.TILE_SIZE/2)
   x, y = player.turtlePos.x, player.turtlePos.y
   love.graphics.setColor(0.2, 0.1, 0.1)
   love.graphics.circle("line", x + game.TILE_SIZE/2, y + game.TILE_SIZE/2, game.TILE_SIZE/2)
   if player.turtleHit then
	  love.graphics.setColor(0.8, 0.1, 0)
   else
	  love.graphics.setColor(0, 0.7, 0.2)
   end
   love.graphics.circle("fill", x + game.TILE_SIZE/2, y + game.TILE_SIZE/2, game.TILE_SIZE/2)
   -- </playfield>
   love.graphics.pop()
end