--[[

Basic idealogy

goal - > go to goal - > check all this and repeat


minecart does check axis dir then -1 1 on opposite axis (x and z)

minecart checks in front and above 

minecart checks in front and below

if in front above start moving up

if in front below start moving down

minecart checks if rail in front then if not check sides and if none then stop

if a rail in front of minecart then when past center of node center, turn towards the available rail and then recenter self onto rail on the new axis


keep it simple stupid

make cart make noise

]]--
local path = minetest.get_modpath("minecart")
dofile(path.."/rail.lua")



local function is_rail(x,y,z)
	return(minetest.get_node_group(minetest.get_node(vector.new(x,y,z)).name,"rail")>0)
end

local minecart = {
	initial_properties = {
		physical = false, -- otherwise going uphill breaks
		collisionbox = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},--{-0.5, -0.4, -0.5, 0.5, 0.25, 0.5},
		visual = "mesh",
		mesh = "minecart.b3d",
		visual_size = {x=1, y=1},
		textures = {"minecart.png"},
		automatic_face_movement_dir = 90.0,
	},

	rider = nil,
	punched = false,
	
}

function minecart:on_rightclick(clicker)
	if not clicker or not clicker:is_player() then
		return
	end
	local player_name = clicker:get_player_name()
	if self.rider and player_name == self.rider then
		self.rider = nil
		carts:manage_attachment(clicker, nil)
	elseif not self.rider then
		self.rider = player_name
		carts:manage_attachment(clicker, self.object)

		-- player_api does not update the animation
		-- when the player is attached, reset to default animation
		
		--player_api.set_animation(clicker, "stand")
	end
end

function minecart:on_activate(staticdata, dtime_s)
	self.object:set_armor_groups({immortal=1})
	if string.sub(staticdata, 1, string.len("return")) ~= "return" then
		return
	end
	local data = minetest.deserialize(staticdata)
	if type(data) ~= "table" then
		return
	end
	self.railtype = data.railtype
	if data.old_dir then
		self.old_dir = data.old_dir
	end
end

function minecart:get_staticdata()
	return minetest.serialize({
	})
end
function minecart:on_punch(puncher, time_from_last_punch, tool_capabilities, dir, damage)
	self.object:remove()
end






--repel from players on track "push"
function minecart:push(self)
	local pos = self.object:getpos()
	for _,object in ipairs(minetest.get_objects_inside_radius(pos, 2)) do
		if object:is_player() then
			local player_pos = object:getpos()
			pos.y = 0
			player_pos.y = 0
			
			local vel = vector.subtract(pos, player_pos)
			vel = vector.normalize(vel)
			local distance = vector.distance(pos,player_pos)
			
			distance = (2-distance)*3
			
			vel = vector.multiply(vel,distance)
			
			self.object:setvelocity(vel)
			
		end
	end
end

function minecart:ride_rail(self)

	--floor position!!!!
	
	local pos = vector.floor(vector.add(self.object:getpos(),0.5))
	local speed = 5 --change to the cart speed soon
	
	local vel = self.object:getvelocity()
	local x = math.abs(vel.x)
	local z = math.abs(vel.z)
	local xdir
	local zdir
	local dir = {x=0,y=0,z=0}
	
	--check direction
	--x axis
	if x > z then
		if vel.x>0 then xdir=1 elseif vel.x<0 then xdir=-1 end
		
		--print(minetest.get_node(vector.new(pos.x,pos.y,pos.z)).name)
		
		--go up
		if is_rail(pos.x+xdir,pos.y+1,pos.z) or (not is_rail(pos.x,pos.y,pos.z) and is_rail(pos.x+xdir,pos.y,pos.z)) then
			--print("up")
			dir.y = speed
			dir.x = xdir*speed
		end
		
		--go down
		if dir.y == 0 and is_rail(pos.x,pos.y-1,pos.z) then
			--print("down")
			dir.y = -speed
			dir.x = xdir*speed
		end
		
		--go flat
		if is_rail(pos.x,pos.y,pos.z) then --currently on rail
			--print("forward inside")
			--correct y position
			if dir.y == 0 and self.object:getpos().y ~= pos.y then
				--print("correcting y")
				local posser = self.object:getpos()
				self.object:moveto(vector.new(posser.x,pos.y,posser.z))
			end
			dir.x = xdir*speed
		end
	--z axis
	elseif z > x then
		if vel.z>0 then zdir=1 elseif vel.z<0 then zdir=-1 end
		
		--print(minetest.get_node(vector.new(pos.x,pos.y,pos.z)).name)
		
		--go up
		if is_rail(pos.x,pos.y+1,pos.z+zdir) or (not is_rail(pos.x,pos.y,pos.z) and is_rail(pos.x,pos.y,pos.z+zdir)) then
			--print("up")
			dir.y = speed
			dir.z = zdir*speed
		end
		
		--go down
		if dir.y == 0 and is_rail(pos.x,pos.y-1,pos.z) then
			--print("down")
			dir.y = -speed
			dir.z = zdir*speed
		end
		
		--go flat
		if is_rail(pos.x,pos.y,pos.z) then --currently on rail
			--print("forward inside")
			--correct y position
			if dir.y == 0 and self.object:getpos().y ~= pos.y then
				--print("correcting y")
				local posser = self.object:getpos()
				self.object:moveto(vector.new(posser.x,pos.y,posser.z))
			end
			dir.z = zdir*speed
		end
	end
	--turn
	local turnx = 0
	local turnz = 0
	
	if vel.x>0 then turnx=1 elseif vel.x<0 then turnx=-1 end
	if vel.z>0 then turnz=1 elseif vel.z<0 then turnz=-1 end
	
	print(turnx, turnz)
	
	if turnx and turnz and dir.y == 0 and not vector.equals(dir, vector.new(0,0,0)) and not is_rail(pos.x+turnx,pos.y-1,pos.z+turnz) and not is_rail(pos.x+turnx,pos.y,pos.z+turnz) and not is_rail(pos.x+turnx,pos.y+1,pos.z+turnz) then
		if x > z then
			print("turning")
			if is_rail(pos.x,pos.y,pos.z+1) then
				dir.z = speed
				dir.x = 0
				--recenter on the rail
				self.object:moveto(pos)
			elseif is_rail(pos.x,pos.y,pos.z-1) then
				dir.z = -speed
				dir.x = 0
				--recenter on the rail
				self.object:moveto(pos)
			end
		elseif z > x then
			if is_rail(pos.x+1,pos.y,pos.z) then
				dir.x = speed
				dir.z = 0
				--recenter on the rail
				self.object:moveto(pos)
			elseif is_rail(pos.x-1,pos.y,pos.z) then
				dir.x = -speed
				dir.z = 0
				--recenter on the rail
				self.object:moveto(pos)
			end
		end
		
	end
	--apply
	--if not vector.equals(dir,vector.new(0,0,0)) then
	self.object:setvelocity(dir)
	--end
	self.oldpos=self.object:getpos()
end



function minecart:on_step(dtime)
	minecart:push(self)
	minecart:ride_rail(self)
end

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




















minetest.register_craftitem("minecart:minecart", {
	description = "Minecart",
	inventory_image = "minecartitem.png",
	wield_image = "minecartitem.png",
	on_place = function(itemstack, placer, pointed_thing)
		if not pointed_thing.type == "node" then
			return
		end
		
		if minetest.get_item_group(minetest.get_node(pointed_thing.under).name, "rail")>0 then
			minetest.add_entity(pointed_thing.under, "minecart:minecart")
		else
			return
		end

		itemstack:take_item()

		return itemstack
	end,
})

minetest.register_craft({
	output = "minecart:minecart",
	recipe = {
		{"main:iron", "", "main:iron"},
		{"main:iron", "main:iron", "main:iron"},
	},
})