LoadedObjects.Particles = {}

Particle = Entity:new()
Particle.type = "Particle"
Particle.display = Animation:new(animation.particle.simple)

function Particle:new(x,y,particle_data)
	local o = Entity:new(x,y)

	o.pos = {x = x, y = y}

	o.speed = particle_data.speed or 0
	o.direction = particle_data.direction or o.direction
	o.sprite_rotation = particle_data.sprite_rotation or o.sprite_rotation
	o.sprite_offset = particle_data.sprite_offset or o.sprite_offset
	o.sprite_scale = particle_data.sprite_scale or o.sprite_scale
	o.sprite_tint = particle_data.sprite_tint or o.sprite_tint
	o.sprite_alpha = particle_data.sprite_alpha or o.sprite_alpha
	o.sprite_alpha_fade = particle_data.sprite_alpha_fade or false
	o.sprite_alpha_base = o.sprite_alpha
	o.sprite_flip = particle_data.sprite_flip or o.sprite_flip

	o.time = particle_data.time or nil
	if o.time ~= nil then
		if particle_data.time_unit ~= nil
		and particle_data.time_unit == "frames" then
			o.time = o.time
		else
			o.time = o.time * game.framerate
		end
	end
	o.timer = 0

	o.vel = {
		x = o.speed * math.cos(o.direction),
		y = o.speed * math.sin(o.direction)
	}

	o.speed_increase = particle_data.speed_increase or 0

	if particle_data.light ~= nil then
		o.light_range = particle_data.light
		local flicker = particle_data.light_flicker or nil
		local color = particle_data.light_color or nil
		o.light = Light:new(o.pos.x,o.pos.y,o.light_range,flicker,color)
	end

	-- animations
	if particle_data.animation ~= nil then
		o.body = Animation:new(particle_data.animation,particle_data.animation_speed)
		o:centerOffset(o.body)
		o:createBox(o.body)
	end

	-- particle id handled differently from other entities
	table.insert(LoadedObjects.Particles,o)
	o.id = #LoadedObjects.Particles

	setmetatable(o, self)
	self.__index = self
	return o
end

function Particle:kill()
	if self.light ~= nil then
		self.light:kill()
	end
	if self.id ~= nil then
		for _, e in pairs(LoadedObjects.Particles) do
			if e.id > self.id then
				e.id = e.id - 1
			end
		end
		table.remove(LoadedObjects.Particles,self.id)
	end
	self = nil
end

function Particle:handleAnimation()
	self.timer = self.timer + 1

	if self.sprite_alpha_fade ~= false then
		self.sprite_alpha = self.sprite_alpha_base*(self.time-self.timer)/self.time
	end

	if self.body ~= nil then
		self.body:animate()
		self:draw(self.body)
	end
end

function Particle:doLogic()
	-- adjust speed
	if self.speed_increase ~= 0 then
		self.speed = self.speed + self.speed_increase
		self.vel.x = self.speed * math.cos(self.direction)
		self.vel.y = self.speed * math.sin(self.direction)
	end

	if self.time ~= nil then
		if self.timer >= self.time then self:kill() end
	end
end

function Particle:doPhysics()
	-- horizontal collision
	self:moveX(
			self.vel.x
	)
	-- vertical collision
	self:moveY(
		self.vel.y
	)
	-- final position
	self:adjustLight()
end

function Particle:debug()
	-- draw center CYAN
	love.graphics.setColor(0,1,1)
	love.graphics.circle("fill", -Camera.pos.x + self.pos.x, -Camera.pos.y + self.pos.y, 1)
end