local mesh = require 'honey.mesh'
local glm = require 'honey.glm'
local Vec3 = glm.Vec3
local ode = honey.ode

local module = {}
setmetatable(module, {__index=_G})
setfenv(1, module)


local function loadTriMesh(space, filename)
	local attrib, shapes, _ = honey.tinyobj.parse_obj(
		filename, honey.tinyobj.FLAG_TRIANGULATE
	)
	local vertices, indices = mesh.loadShape(shapes[1], attrib)

	trimeshdata = ode.GeomTriMeshDataCreate()
	ode.GeomTriMeshDataBuild(trimeshdata, vertices, indices)
	return ode.CreateTriMesh(space, trimeshdata)
end


--===== collision space =====--


local function createGeom(self, id, collision)
	local geom
	if collision.class == "sphere" then
		geom = ode.CreateSphere(self.space, collision.radius)
	elseif collision.class == "capsule" then
		geom = ode.CreateCapsule(self.space, collision.radius, collision.length)
	elseif collision.class == "plane" then
		local node = self.db:getComponent(id, "node")
		local m = node.matrix
		local normal = node.matrix:mulv3(Vec3{0,1,0}):normalize()
		local position = Vec3{m[1][4], m[2][4], m[3][4]}
		print(position)
		local d = normal:dot(position)
		print(normal, d)
		geom = ode.CreatePlane(self.space, normal[1], normal[2], normal[3], d)
	elseif collision.class == "ray" then
		geom = ode.CreateRay(self.space, collision.length)
	elseif collision.class == "trimesh" then
		geom = loadTriMesh(self.space, collision.filename)
	end

	ode.GeomSetCategoryBits(geom, collision.category or 1)
	ode.GeomSetCollideBits(geom, collision.collide or 0xffffffff)
	ode.GeomSetData(geom, id)
	
	collision._geom = geom
	collision._gc = honey.util.gc_canary(function()
		print("release geom for id"..id)
		ode.GeomDestroy(geom)
	end)
end


local function isPlaceable(collision)
	if collision.class == "ray" then
		return true
	elseif collision.class == "trimesh" then
		return true
	end
	return false
end


system = function(params)
	local db = params.db
	local space = params.space
	return {
		db=db,
		space=space,
		priority=0,
		update = function(self, dt)
			local query = self.db:queryComponent("collision")
			for id, collision in pairs(query) do
				if not collision._geom then
					createGeom(self, id, collision)
					print(id, collision._geom)
				end
				if 
					not self.db:getComponent(id, "physics") and 
					isPlaceable(collision) 
				then
					-- no attached physics body, update position & orientation 
					-- from node transform
					local node = self.db:getComponent(id, "node")
					local m = node._matrix or node.matrix
					local geom = collision._geom
					ode.GeomSetPosition(
						geom,
						m[1][4],
						m[2][4],
						m[3][4]
					)
					ode.GeomSetRotation(
						geom,
						m[1][1], m[1][2], m[1][3],
						m[2][1], m[2][2], m[2][3],
						m[3][1], m[3][2], m[3][3]
					)
				end
			end
		end
	}
end



return module