local move_acceleration=8000
local max_speed=4000

local gravity=-1000

local ground_contact=false
local wall_contact=false

-- pre-has for system parameters to speed up process
local msg_contact_point_response=hash("contact_point_response")
local msg_animation_done=hash("animation_done")
local group_obstacle = hash("ground")
local group_wall = hash("wall")

-- animations
local anime_walk=hash("Walk")
local anim_idle=hash("Idle")
local anime_hit = hash("Hit")
local anime_attack=hash("Attack")





function init(self)
	-- Add initialization code here
	-- Learn more: https://defold.com/manuals/script/
	-- Remove this function if not needed
	-- init enemy velocity
	self.velocity=vmath.vector3(0,0,0)
	self.movement=1

	self.anim=nil
end

function final(self)
	-- Add finalization code here
	-- Learn more: https://defold.com/manuals/script/
	-- Remove this function if not needed

end

local function play_animation(self, anim)
	if self.anim ~= anim then
		msg.post("#sprite","play_animation",{id=anim})
		self.anim=anim
	end
end

local function update_animations(self)
	sprite.set_hflip("#sprite", self.movement<0)
	--go.set_rotation(vmath.quat_rotation_y(math.rad(180)))
	if (self.movement<0) then
		physics.set_hflip("#CollisionSkeleton", true);
		physics.set_hflip("#Hitbox", true);
	else
		physics.set_hflip("#CollisionSkeleton", false);
		physics.set_hflip("#Hitbox",false);
	end


	if (self.ground_contact) then
		if (self.velocity.x == 0) then
			play_animation(self,anim_idle)
		else
			play_animation(self,anim_walk)
		end
	end
end


function update(self, dt)
	-- Add update code here
	-- Learn more: https://defold.com/manuals/script/
	-- Remove this function if not needed

	local target_speed=self.movement*max_speed
	local speed_diff = target_speed-self.velocity.x

	local acceleration = vmath.vector3(0,gravity,0)

	if(speed_diff~=0) then
		if(speed_diff<0) then
			acceleration.x= - move_acceleration
		else
			acceleration.x = move_acceleration
		end

	end

	local dv = acceleration * dt
	if (math.abs(dv.x)>math.abs(speed_diff)) then
		dv.x = speed_diff
	end

	local v0 = self.velocity

	local v0 = self.velocity + dv

	local dp= (v0 +self.velocity) * dt * 0.5

	update_animations(self)

	go.set_position(go.get_position() + dp)
	self.correction=vmath.vector3()

	self.ground_contact=false
	self.wall_contact=false

end


local function handle_obstacle_contact(self,normal,distance)
	local proj=vmath.dot(self.correction, normal)
	local comp=(distance-proj)*normal

	self.correction=self.correction+comp

	go.set_position(go.get_position()+comp)

	if normal.y > 0.7 then
		self.ground_contact=true
	end

	proj=vmath.dot(self.velocity,normal)
	if proj<0 then
		self.velocity = self.velocity - proj*normal
	end
end


local function handle_wall_contact(self,normal,distance)
	local proj=vmath.dot(self.correction, normal)
	local comp=(distance-proj)*normal

	self.correction=self.correction+comp

	go.set_position(go.get_position()+comp)

	

	
	self.wall_contact=true
	self.movement=normal.x
	

	proj=vmath.dot(self.velocity,normal)
	if proj<0 then
		self.velocity = self.velocity - proj*normal
	end
end

function on_message(self, message_id, message, sender)
	-- Add message-handling code here
	-- Learn more: https://defold.com/manuals/message-passing/
	-- Remove this function if not needed

	if message_id == msg_contact_point_response then
		if message.other_group == group_obstacle then
			handle_obstacle_contact(self, message.normal, message.distance)
		elseif message.group == group_wall and not self.wall_contact then
			handle_wall_contact(self, message.normal, message.distance)
		end
	end
end

function on_input(self, action_id, action)
	-- Add input-handling code here. The game object this script is attached to
	-- must have acquired input focus:
	--
	--    msg.post(".", "acquire_input_focus")
	--
	-- All mapped input bindings will be received. Mouse and touch input will
	-- be received regardless of where on the screen it happened.
	-- Learn more: https://defold.com/manuals/input/
	-- Remove this function if not needed
end

function on_reload(self)
	-- Add reload-handling code here
	-- Learn more: https://defold.com/manuals/hot-reload/
	-- Remove this function if not needed
end