local glm = honey.glm
local Vec3 = require 'honey.vec3'

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

local RowLookup = {}
function RowLookup.new(_, row, data)
	local self = {
		row=row,
		data=data,
	}
	setmetatable(self, RowLookup)
	return self
end
setmetatable(RowLookup, {__call=RowLookup.new})
function RowLookup.__index(self, col)
	return glm.mat4_get(self.data, col-1, self.row-1)
end
function RowLookup.__newindex(self, col, value)
	return glm.mat4_set(self.data, col-1, self.row-1, value)
end



Mat4 = {}

function Mat4.new(_, self, values)
	local self = {}
	self.type = "mat4"
	self.data = glm.mat4_create()
	setmetatable(self, Mat4)
	if values then
		self[1][1] = values[1]
		self[1][2] = values[2]
		self[1][3] = values[3]
		self[1][4] = values[4]

		self[2][1] = values[5]
		self[2][2] = values[6]
		self[2][3] = values[7]
		self[2][4] = values[8]

		self[3][1] = values[9]
		self[3][2] = values[10]
		self[3][3] = values[11]
		self[3][4] = values[12]

		self[4][1] = values[13]
		self[4][2] = values[14]
		self[4][3] = values[15]
		self[4][4] = values[16]
	end
	return self
end
setmetatable(Mat4, {__call=Mat4.new})


function Mat4.__index(self, key)
	if type(key) == "number" then
		return RowLookup(key, self.data)
	else
		return Mat4[key]
	end
end


function Mat4.__tostring(self)
	return string.format(
		"/ %0.4f, %0.4f, %0.4f, %0.4f \\\n" ..
		"| %0.4f, %0.4f, %0.4f, %0.4f |\n" ..
		"| %0.4f, %0.4f, %0.4f, %0.4f |\n" ..
		"\\ %0.4f, %0.4f, %0.4f, %0.4f /",
		self[1][1], self[1][2], self[1][3], self[1][4],
		self[2][1], self[2][2], self[2][3], self[2][4],
		self[3][1], self[3][2], self[3][3], self[3][4],
		self[4][1], self[4][2], self[4][3], self[4][4]
	)
end


function Mat4.__mul(self, other)
	if other.type == "mat4" then
		local dest = Mat4()
		glm.mat4_mul(self.data, other.data, dest.data)
		return dest
	elseif other.type == "vec4" then
		-- todo
	elseif other.type == "vec3" then
		local dest = Vec3()
		glm.mat4_mulv3(self.data, other.data, 1.0, dest.data)
		return dest
	else
		error(string.format("cannot multiply Mat4 by %s", type(other)))
	end
end


function Mat4.copyTo(self, dest)
	glm.mat4_copy(self.data, dest.data)
end


function Mat4.identity(self)
	glm.mat4_identity(self.data)
	return self
end


function Mat4.zero(self)
	glm.mat4_zero(self.data)
	return self
end


function Mat4.translate(self, vec)
	glm.translate(self.data, vec.data)
	return self
end


function Mat4.rotateX(self, angle)
	glm.rotate_x(self.data, angle, self.data)
	return self
end
function Mat4.rotateY(self, angle)
	glm.rotate_y(self.data, angle, self.data)
	return self
end
function Mat4.rotateZ(self, angle)
	glm.rotate_z(self.data, angle, self.data)
	return self
end


function Mat4.scale(self, vec)
	glm.scale(self.data, vec.data)
	return self
end


function Mat4.perspective(self, fovy, aspect, near, far)
	glm.perspective(fovy, aspect, near, far, self.data)
	return self
end
function Mat4.perspectiveResize(self, aspect)
	glm.perspective_resize(aspect, self.data)
	return self
end


return module.Mat4