Entity = {}

function Entity:New(x,y)
	o = {}
	o.pos = {x = x, y = y}
	o.vel = {x = 0, y = 0}
  o.target = {x = 0, y = 0}
  o.hitbox = 0
	o.angle = 0
	o.direction = 0
  o.show_health = false
	o.id = {}
	setmetatable(o, self)
	self.__index = self
	return o
end

function Entity:Damage(damage)
	self.health = self.health - damage
	if self.health <= 0 then
		self:Kill()
	end
end

function Entity:DrawHealth()
	local width = 400
	local height = 10
		love.graphics.setColor(1,1,1)
  love.graphics.rectangle(
		"fill",
		self.pos.x - width/2,
		self.pos.y - height * self.draw_scale,
		width,
		height
	)
	love.graphics.setColor(1,0,0)
	love.graphics.rectangle(
		"fill",
		self.pos.x - width/2+1,
		self.pos.y - height * self.draw_scale+1,
		self.health/self.max_health*(width-2),
		height-2
	)
		love.graphics.setColor(1,1,1)

end

function Entity:AddList(list)
	table.insert(list,self)

	if list == List.Simulate then
		self.id.Simulate = #list
	elseif list == List.Enemy then
		self.id.Enemy = #list
	elseif list == List.EnemyBullet then
		self.id.EnemyBullet = #list
	elseif list == List.FriendlyBullet then
		self.id.FriendlyBullet = #list
	end
end

function Entity:CollisionWith(obj)
	if math.sqrt((obj.pos.x-self.pos.x)^2 + (obj.pos.y-self.pos.y)^2) < obj.hitbox + self.hitbox  then
		return true
	else
		return false
	end
end

function Entity:RemoveList(list)
	if list == List.Simulate then
		for _, e in pairs(list) do
			if e.id.Simulate > self.id.Simulate then
				e.id.Simulate = e.id.Simulate - 1
			end
		end
		table.remove(list,self.id.Simulate)
	elseif list == List.Enemy then
		for _, e in pairs(list) do
			if e.id.Enemy > self.id.Enemy then
				e.id.Enemy = e.id.Enemy - 1
			end
		end
		table.remove(list,self.id.Enemy)
	elseif list == List.EnemyBullet then
		for _, e in pairs(list) do
			if e.id.EnemyBullet > self.id.EnemyBullet then
				e.id.EnemyBullet = e.id.EnemyBullet - 1
			end
		end
		table.remove(list,self.id.EnemyBullet)
	elseif list == List.FriendlyBullet then
		for _, e in pairs(list) do
			if e.id.FriendlyBullet > self.id.FriendlyBullet then
				e.id.FriendlyBullet = e.id.FriendlyBullet - 1
			end
		end
		table.remove(list,self.id.FriendlyBullet)
	end
end

function Entity:AngleTowards(x,y)
  target_x = x - self.pos.x
  target_y = y - self.pos.y

  self.angle = GetAngle(target_x,target_y)
end

function Entity:Kill()
	if self.id.Simulate ~= nil then
		self:RemoveList(List.Simulate)
	end
	if self.id.Enemy ~= nil then
		self:RemoveList(List.Enemy)
	end
	if self.id.EnemyBullet ~= nil then
		self:RemoveList(List.EnemyBullet)
	end
	if self.id.FriendlyBullet　~= nil then
		self:RemoveList(List.FriendlyBullet)
	end

	self = nil
end

function Entity:MoveTowards(x,y,speed)
  target_x = x - self.pos.x
  target_y = y - self.pos.y

	local angle = GetAngle(target_x,target_y)

	if speed ~= 0 then
		if target_x ~= 0 then
	  	self.vel.x = speed * math.cos(angle)
		else
			self.vel.x = 0
		end
		if target_y ~= 0 then
			self.vel.y = speed * math.sin(angle)
		else
			self.vel.y = 0
		end
	end
end

require "scripts/entities/player"
require "scripts/entities/enemy/fang"
require "scripts/entities/enemy/shooter"
require "scripts/entities/bullet"