require 'honey.std'

local glfw = honey.glfw
local gl = honey.gl
local Vec3 = honey.Vec3
local Mat4 = honey.Mat4
local Quaternion = honey.Quaternion
local ecs = honey.ecs
local sys = honey.standardSystems
local dispatch = sys.dispatch
local ode = honey.ode
local nvg = honey.nvg


-- initialize honey
local window = honey.init()

-- setup vector graphics
local vg = nvg.CreateContext()
local november = nvg.CreateFont(vg, "November", "assets/november.regular.ttf")
local vw, vh = 640, 480

-- setup physics
local space = ode.HashSpaceCreate(ode.Space0)
local world = ode.WorldCreate()
ode.WorldSetGravity(world, 0, -10, 0)
ode.WorldSetCFM(world, 1e-5)
local physicsGc = honey.util.gc_canary(function()
	ode.SpaceDestroy(space)
	ode.WorldDestroy(world)
end)


-- setup ecs
local entities = ecs.EntityDb()
local systems = ecs.SystemDb(entities)

local camera = entities:createEntity()
entities:addComponents(camera, {
	camera={
		projection=Mat4():perspective(math.rad(45), 640/480, 0.1, 100),
	},
	transform={
		matrix=Mat4():identity():translate(Vec3{0, 0, -6}),
	},
	z = {value=-60},
	script={
		script="cameraRotationScript",
	},
	onKey = {
		script="cameraKeyHandler",
	},
})

systems:addSystem(sys.transform)
systems:addSystem(sys.renderCamera, {camera=camera})
systems:addSystem(sys.script)
systems:addSystem(sys.physics, {space=space, world=world})
package.loaded['baseRotationScript'] = function(entities, id, dt)
	local transform = entities:getComponent(id, "transform")
	transform.matrix:rotateZ(math.pi * dt)
end
package.loaded['cameraRotationScript'] = function(entities, id, dt)
	local transform = entities:getComponent(id, "transform")
	local z = entities:getComponent(id, "z")
	transform.matrix
		:identity()
		:translate(Vec3{0, 0, z.value + math.sin(math.pi * glfw.GetTime())})
end
package.loaded['cameraKeyHandler'] = function(entities, id, data)
	local z = entities:getComponent(id, "z")
	if data.key == glfw.KEY_W then
		z.value = z.value + 1
	elseif data.key == glfw.KEY_S then
		z.value = z.value - 1
	end	
end


local id = entities:createEntity()
entities:addComponents(id, {
	renderMesh = {
		textures = { ourTexture={ filename="77155.png" } },
		shader = { vertex="vertex.glsl", fragment="fragment.glsl" },
		mesh = { filename="assets/icosahedron.obj", index=1 },
	},
	transform = {
		matrix = Mat4():identity():rotateZ(math.rad(45)),
	},
	physics = {
		mass = {
			class = "sphere",
			density = 1,
			radius = 1,
		},
		velocity = Vec3{ 0, 10, 0 },
		angularVelocity = Vec3{ 0, 1, 0 },
	},
})

local id2 = entities:createEntity()
entities:addComponents(id2, {
	renderMesh = {
		shader = { vertex="vertex.glsl", fragment="fragment.glsl" },
		mesh = { filename="assets/tetrahedron.obj", index=1 },
	},
	transform = {
		parent=id,
		matrix=Mat4():identity():translate(Vec3{0, 2, 0}),
	},
})



-- close window on ESCAPE key
window:setKeyCallback(function(_, key, scancode, action)
	dispatch(entities, "onKey", {key=key, scancode=scancode, action=action})
	if action == glfw.PRESS then
		if key == glfw.KEY_ESCAPE then
			window:setShouldClose(true)
		elseif key == glfw.KEY_SPACE then
			entities:save("save")
		elseif key == glfw.KEY_L then
		end
	end
end)

-- resize window correctly
window:setFramebufferSizeCallback(function(_, width, height)
	gl.Viewport(0, 0, width, height)
	vw, vh = width, height
	dispatch(entities, "onWindowResize", { width=width, height=height })
end)

package.loaded["cameraHandleResize"] = function(entities, id, data)
	local camera = entities:getComponent(id, "camera")
	camera.projection:perspectiveResize(data.width/data.height)
end
entities:addComponent(camera, "onWindowResize", { script = "cameraHandleResize" })

-- averager (for fps)
function averager(memory)
	local buf = {}
	local avg = 0
	for i=1,memory do table.insert(buf, 0) end
	return function(value)
		table.insert(buf, value)
		local val = table.remove(buf, 1)
		avg = avg + value - val
		return avg / memory
	end
end
local fpsAverage = averager(200)



entities:load("save")


-- main loop
honey.loop(window, function(dt)
	gl.ClearColor(0.2, 0.4, 1.0, 1.0)
	gl.Clear(gl.COLOR_BUFFER_BIT + gl.DEPTH_BUFFER_BIT + gl.STENCIL_BUFFER_BIT)

	gl.Enable(gl.DEPTH_TEST)
	gl.Disable(gl.CULL_FACE)

	systems:update(dt)
	nvg.BeginFrame(vg, vw, vh, 1.0)
	nvg.StrokeColor(vg, nvg.RGBf(1, 1, 1))
	nvg.FontFace(vg, "November")
	nvg.Text(vg, 50, 50, "fps: "..tostring(math.floor(1/dt)))
	nvg.EndFrame(vg)
end)

-- clean up
honey.terminate()