require 'honey.std'

local glfw = honey.glfw
local gl = honey.gl
local Vec3 = honey.Vec3
local Mat4 = honey.Mat4
local ecs = honey.ecs
local systems = honey.standardSystems


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

-- create camera matrices
local camera = {
	view=Mat4():identity():translate(Vec3{0, 0, -60}),
	projection=Mat4():perspective(math.rad(45), 640/480, 0.1, 100),
}

-- setup ecs
local level = ecs.Level()
level:addSystem(systems.transformCascade)
level:addSystem(systems.renderCam(camera))
level:addSystem(systems.update)

-- create shader
local shader = honey.Shader{
	vertexFile = "vertex.glsl",
	fragmentFile = "fragment.glsl",
}

-- load models
local plane = honey.mesh.loadFile("assets/plane.obj")[1]
local tetra = honey.mesh.loadFile("assets/tetrahedron.obj")[1]
local cube = honey.mesh.loadFile("assets/cube.obj")[1]
local octa = honey.mesh.loadFile("assets/octahedron.obj")[1]
local dodeca = honey.mesh.loadFile("assets/dodecahedron.obj")[1]
local icosa  = honey.mesh.loadFile("assets/icosahedron.obj")[1]

-- update function for each entity
function updateTransform(self, dt)
	self.transform:rotateY(0.3 * math.pi * dt)
	self.transform:rotateX(0.1 * math.pi * dt)
end

-- create entities
function growLine(prev, depth)
	if depth == 0 then return prev end

	local entity = {
		transform=Mat4():identity():translate(Vec3{2, 0, 0}),
		parent=false,
		mesh=octa,
		shader=shader,
		update=updateTransform,
	}
	prev.parent = entity
	level:addEntity(prev)
	return growLine(entity, depth-1)
end

local leaf = {
	transform=Mat4():identity():translate(Vec3{2, 0, 0}),
	parent=false,
	mesh=tetra,
	shader=shader,
}
local root = growLine(leaf, 24)
root.update = function(self, dt)
	self.transform:rotateY(0.2 * math.pi * dt)
end
level:addEntity(root)

local groundPlane = {
	transform=Mat4():identity():translate(Vec3{0, -2, 0}):scale(Vec3{10, 10, 10}),
	parent=false,
	mesh=plane,
	shader=shader,
}
level:addEntity(groundPlane)

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

-- resize window correctly
window:setFramebufferSizeCallback(function(_, width, height)
	gl.Viewport(0, 0, width, height)
	camera.projection:perspectiveResize(width/height)
end)

-- 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)
	level:update(dt)
end)

-- clean up
honey.terminate()