--[[

Copyright 2016 - Auke Kok <sofar@foo-projects.org>

License:
    - Code: WTFPL
    - Models and textures: CC-BY-SA-3.0

Usage: /give <name> camera:camera

    left click a camera item to start recording. While recording:
    - use up/down to accelerate/decelerate
    - use jump to brake
    - use crouch to stop recording

    right click a camera item to play back a recording. While playing back:
    - use crouch to stop playing back

--]]

local recordings = {}

local camera = {
	description = "Camera",
	physical = false,
	visual = "mesh",
	mesh = "camera.obj",
	textures = { "camera_camera.png" },
	collisionbox = {-0.5,-0.5,-0.5, 0.5,0.5,0.5},
	driver = nil,
	mode = 0,
	velocity = {x=0, y=0, z=0},
	old_pos = nil,
	old_velocity = nil,
	pre_stop_dir = nil,
	MAX_V = 20,
	init = function(self, player, mode)
		self.driver = player
		self.mode = mode
		self.path = {}
	end,
}

function camera:on_step(dtime)
	if not self.driver then
		self.object:remove()
		return
	end
	local pos = self.object:getpos()
	local vel = self.object:getvelocity()
	local dir = self.driver:get_look_dir()

	if self.mode == 0 then
		-- record
		self.path[#self.path + 1] = {
			pos = pos,
			velocity = vel,
			pitch = self.driver:get_look_pitch(),
			yaw = self.driver:get_look_yaw()
		}

		-- player control of vehicle
		-- always modify yaw/pitch to match player
		self.object:set_look_pitch(self.driver:get_look_pitch())
		self.object:set_look_yaw(self.driver:get_look_yaw())
	
		-- accel/decel/stop
		local ctrl = self.driver:get_player_control()
		local speed = vector.distance(vector.new(), vel)
		if ctrl.up then
			-- forward accelerate
			speed = math.min(speed + 0.1, 20)
		end
		if ctrl.down then
			-- backward acccelerate
			speed = math.max(speed - 0.1, -20)
		end
		if ctrl.jump then
			-- brake
			speed = math.max(speed * 0.9, 0.0)
		end
		if ctrl.sneak then
			-- stop recording!
			self.driver:set_detach()
			minetest.chat_send_player(self.driver:get_player_name(), "Recorded stopped after " .. #self.path .. " points")
			recordings[self.driver:get_player_name()] = table.copy(self.path)
			self.object:remove()
			return
		end
		self.object:setvelocity(vector.multiply(self.driver:get_look_dir(), speed))
	elseif self.mode == 1 then
		-- stop playback ?
		local ctrl = self.driver:get_player_control()
		if ctrl.sneak or #self.path < 1 then
			-- stop playback
			self.driver:set_detach()
			minetest.chat_send_player(self.driver:get_player_name(), "Playback stopped")
			self.object:remove()
			return
		end

		-- playback
		self.object:moveto(self.path[1].pos, true)
		self.driver:set_look_yaw(self.path[1].yaw - (math.pi/2))
		self.driver:set_look_pitch(0 - self.path[1].pitch)
		self.object:setvelocity(self.path[1].velocity)
		table.remove(self.path, 1)
	end
end

minetest.register_entity("camera:camera", camera)

minetest.register_craftitem("camera:camera", {
	description = "Camera",
	inventory_image = "camera_item.png",
	on_use = function(itemstack, player, pointed_thing)
		local object = minetest.add_entity(player:getpos(), "camera:camera")
		object:get_luaentity():init(player, 0)
		object:setyaw(player:get_look_yaw())
		player:set_attach(object, "", {x=0,y=10,z=0}, {x=0,y=0,z=0})
	end,
	on_secondary_use = function(itemstack, player, pointed_thing)
		if not recordings[player:get_player_name()] then
			return
		end
		local object = minetest.add_entity(player:getpos(), "camera:camera")
		object:get_luaentity():init(player, 1)
		object:setyaw(player:get_look_yaw())
		player:set_attach(object, "", {x=5,y=10,z=0}, {x=0,y=0,z=0})
		object:get_luaentity().path = table.copy(recordings[player:get_player_name()])
	end,
})