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 stdSystem = honey.standardSystems
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 ecs
local db = ecs.Database()

local camera = db:createEntity()
db:addComponent(camera, "camera", {
	projection=Mat4():perspective(math.rad(45), 640/480, 0.1, 100),
})
db:addComponent(camera, "transform", {
	matrix=Mat4():identity():translate(Vec3{0, 0, -6}),
})
db:addComponent(camera, "script", {
	name = "cameraRotationScript",
})


db:addSystem(stdSystem.transform)
db:addSystem(stdSystem.renderCamera, {camera=camera})
db:addSystem(stdSystem.script)
package.loaded['baseRotationScript'] = function(db, id, dt)
	local transform = db:getComponent(id, "transform")
	transform.matrix:rotateZ(math.pi * dt)
end
package.loaded['cameraRotationScript'] = function(db, id, dt)
	local transform = db:getComponent(id, "transform")
	transform.matrix:identity():translate(Vec3{0, 0, -6 + math.sin(math.pi * glfw.GetTime())})
end


function transmitMessage(msg, data)
	local query = db:queryComponent(msg)
	for id, handler in pairs(query) do
		local f = require(handler.scriptName)
		f(db, id, data)
	end
end


local id = db:createEntity()
db:addComponent(id, "renderMesh", {
	textures = {
		ourTexture={ filename="77155.png" },
	},
	shader = { vertex="vertex.glsl", fragment="fragment.glsl" },
	mesh = { filename="assets/icosahedron.obj", index=1 },
})
db:addComponent(id, "transform", {
	matrix = Mat4():identity():rotateZ(math.rad(45)),
})
db:addComponent(id, "script", {
	name = "baseRotationScript",
})

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



-- close window on ESCAPE key
window:setKeyCallback(function(_, key, scancode, action)
	if action == glfw.PRESS then
		if key == glfw.KEY_ESCAPE then
			window:setShouldClose(true)
		end
	end
end)

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

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


-- 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)

	db: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()