-- gravity pulling the player down in pixel units/sˆ2
local gravity = -20

-- take-off speed when jumping in pixel units/s
local jump_takeoff_speed = 900

go.property("lives", 4)

function init(self)
	-- this lets us handle input in this script
	msg.post(".", "acquire_input_focus")
	-- save position
	self.position = go.get_position()
	self.lives = go.get("#", "lives")
	msg.post("#", "reset")
end

function final(self)
	msg.post(".", "release_input_focus")
end

local function play_animation(self, anim)
	-- only play animations which are not already playing
	if self.anim ~= anim then
		-- tell the spine model to play the animation
		spine.play("#spinemodel", anim, go.PLAYBACK_LOOP_FORWARD, 0.15)
		-- remember which animation is playing
		self.anim = anim
	end
end

local function update_animation(self)
	-- make sure the right animation is playing
	if self.ground_contact then
		play_animation(self, hash("run_right"))
	else
		if self.velocity.y > 0 then
			play_animation(self, hash("jump_right"))
		else
			play_animation(self, hash("fall_right"))
		end
	end
end

function update(self, dt)
	local gravity = vmath.vector3(0, gravity, 0)

	if not self.ground_contact then
		self.velocity = self.velocity + gravity
	end

	-- apply it to the player character
	go.set_position(go.get_position() + self.velocity * dt)

	update_animation(self)

	-- reset volatile state
	self.correction = vmath.vector3()
	self.ground_contact = false

	if self.teleport == true then
		self.position = vmath.vector3(100, self.position.y, self.position.z)
		go.set_position(self.position)
	end
	self.teleport = false
end

local function handle_geometry_contact(self, normal, distance)
	-- project the correction vector onto the contact normal
	-- (the correction vector is the 0-vector for the first contact point)
	local proj = vmath.dot(self.correction, normal)
	-- calculate the compensation we need to make for this contact point
	local comp = (distance - proj) * normal
	-- add it to the correction vector
	self.correction = self.correction + comp
	-- apply the compensation to the player character
	go.set_position(go.get_position() + comp)
	-- check if the normal points enough up to consider the player standing on the ground
	-- (0.7 is roughly equal to 45 degrees deviation from pure vertical direction)
	if normal.y > 0.7 then
		self.ground_contact = true
	end
	-- project the velocity onto the normal
	proj = vmath.dot(self.velocity, normal)
	-- if the projection is negative, it means that some of the velocity points towards the contact point
	if proj < 0 then
		-- remove that component in that case
		self.velocity = self.velocity - proj * normal
	end
end

function on_message(self, message_id, message, sender)
	if message_id == hash("reset") then
		self.velocity = vmath.vector3(0, 0, 0)
		self.correction = vmath.vector3()
		self.ground_contact = false
		self.anim = nil
		go.set(".", "euler.z", 0)
		go.set_position(self.position)
		msg.post("#collisionobject", "enable")

	elseif message_id == hash("contact_point_response") then
		-- check if we received a contact point message
		if message.group == hash("danger") then
			-- Die and restart
			particlefx.play("#deathfx")
			play_animation(self, hash("die_right"))
			msg.post("#collisionobject", "disable")
			msg.post("hud", "set_lives", { lives = self.lives })
			go.animate(".", "euler.z", go.PLAYBACK_ONCE_FORWARD, 160, go.EASING_LINEAR, 0.7)
			go.animate(".", "position.y", go.PLAYBACK_ONCE_FORWARD, go.get_position().y - 200, go.EASING_INSINE, 0.5, 0.2,
				function()
					if self.lives > 1 then
  				    	msg.post("controller#script", "reset")
  		    		end
					self.lives = self.lives - 1
					if self.lives == 0 then
						msg.post("hud", "show_game_over")
						msg.post("#", "disable")
					else
						msg.post("#", "reset")
					end
				end)

		elseif message.group == hash("geometry") then
			handle_geometry_contact(self, message.normal, message.distance)
		end
	end
end

local function jump(self)
	-- only allow jump from ground
	if self.ground_contact then
		-- set take-off speed
		self.velocity.y = jump_takeoff_speed
	end
end

local function abort_jump(self)
	-- cut the jump short if we are still going up
	if self.velocity.y > 0 then
		-- scale down the upwards speed
		self.velocity.y = self.velocity.y * 0.5
	end
end

function on_input(self, action_id, action)
	if action_id == hash("jump")then
		jump(self)
	elseif action_id == hash("teleport") then
		print("teleported")
		self.teleport = true
	end
end