local SCROLL_SPEED = 100
local RESISTENCE = 1
local SPEED = 100

local FONT = love.graphics.newFont("cour.ttf", 30)
love.graphics.setFont(FONT)


local COLOR_PLANET = {100/255,200/255,100/255}
local COLOR_STARS = {1,1,1}

local stars = {}

function generate_stars (nr, mindist)
	local mindist = mindist * mindist
	while nr>0 do
		local x, y = 50+math.random(700), 50+math.random(500)
		for _, o_spot in ipairs(stars) do
			if math.pow(o_spot[1]-x, 2) + math.pow(o_spot[1]-y, 2) < mindist then
				x = 0
			end
		end
		if x ~= 0 then
			table.insert(stars, {x, y})
			nr = nr - 1
		end
	end
end

local function shaders ()
	hint = {
		text = "Dude, there's nothing more, please leave :/",
		time = 100,
		align = "left"
	}
end

local function wait_on_shaders_2 ()
	hint = {
		text = "",
		time = 60,
		align = "right",
		func = exit
	}
end

local function shaders ()
	hint = {
		text = "Fucking shaders, right?\nTook me way too long a time to create this bad effect :/",
		time = 10,
		align = "left",
		func = wait_on_shaders_2
	}
end

local function wait_on_shaders ()
	hint = {
		text = "",
		time = 5,
		align = "right",
		func = shaders
	}
	local shader = love.graphics.newShader("stars.glsl")
	love.graphics.setShader(shader)
	shader:send("stars", unpack(stars))
end

local function love_the_final_frontier()
	hint = {
		text = "LÖVE, the final frontier...",
		time = 0.2,
		align = "right",
		func = wait_on_shaders
	}
end

hint = {
	text = "SPACE, the final frontier...",
	time = 5,
	func = love_the_final_frontier,
	align = "right"
}

local player = {
	x = 400,
	y = 300,
	dx = 0,
	dy = 0
}

function draw_player (x,y)
	love.graphics.setColor(COLOR_STARS)
	local py = player.rocket and y + math.min(0, player.rocket) or y
	local PLAYER_POLY = {
		x-30, py+20,
		x+20, py+20,
		x+30, py,
		x+10, py,
		x+10, py-20,
		x,    py-20,
		x,    py,
		x-30, py,
	}
	local ROCKET_POLY = {
		x,    y+20-30,
		x-10, y+20-10,
		x-20, y+20+40,
		x-5,  y+20+20,
		x-2,  y+20+30,
		x+2,  y+20+37,
		x+5,  y+20+20,
		x+20, y+20+40,
		x+10, y+20-10,
	}
	love.graphics.polygon('fill', PLAYER_POLY)
	love.graphics.polygon('fill', ROCKET_POLY)
end

function update_player (dt)
	local ddy = love.keyboard.isDown("w") and -1 or love.keyboard.isDown("s") and 1 or 0
	local ddx = love.keyboard.isDown("a") and -1 or love.keyboard.isDown("d") and 1 or 0

	if ddx ~= 0 and ddy ~= 0 then
		ddx, ddy = ddx*math.sqrt(2), ddy*math.sqrt(2)
	end

	player.dx, player.dy = player.dx*RESISTENCE + SPEED*ddx*dt, player.dy*RESISTENCE + SPEED*ddy*dt

	player.x, player.y = (player.x + player.dx * dt+800) % 800, (player.y + player.dy * dt+600) % 600
end

function draw_planet (x, y, size, color)
	love.graphics.setColor(color)
	love.graphics.circle("fill", x, y, size)
end

local scroll = 0

function love.update (dt)
	scroll  = scroll + dt * SCROLL_SPEED
	update_player(dt)

	hint.time = hint.time - dt
	if hint.time <= 0 and hint.func then
		hint.func()
	end
end

function draw_stars ()
	love.graphics.setColor(COLOR_STARS)
	for _, star in ipairs(stars) do
		love.graphics.circle("fill", star[1], star[2], 2)
	end
end

local CANVAS = love.graphics.newCanvas()

local function draw_canvas()
	love.graphics.setCanvas(CANVAS)
	love.graphics.clear()
		draw_stars()
		draw_planet(400, scroll+500, 200, COLOR_PLANET)
		draw_player(player.x, player.y)

		if hint.time > 0 then
			love.graphics.printf(hint.text, 100, 100, 600, hint.align or "center")
		end
	love.graphics.setCanvas()
end

function love.draw ()
	draw_canvas()
	love.graphics.setColor(COLOR_STARS)
	love.graphics.draw(CANVAS)
end

math.randomseed(os.time())
generate_stars(30, 100)
love.graphics.setBackgroundColor(26/255,26/255,26/255)