use dyn_any::{DynAny, StaticType};
use glam::{DAffine2, DVec2};
use graphene_core::raster::{Alpha, BlendMode, BlendNode, Image, ImageFrame, Linear, LinearChannel, Luminance, Pixel, RGBMut, Raster, RasterMut, RedGreenBlue, Sample};
use graphene_core::transform::Transform;

use graphene_core::value::CopiedNode;
use graphene_core::{Color, Node};

use std::fmt::Debug;
use std::marker::PhantomData;
use std::path::Path;

#[derive(Debug, DynAny)]
pub enum Error {
	IO(std::io::Error),
	Image(image::ImageError),
}

impl From<std::io::Error> for Error {
	fn from(e: std::io::Error) -> Self {
		Error::IO(e)
	}
}

pub trait FileSystem {
	fn open<P: AsRef<Path>>(&self, path: P) -> Result<Box<dyn std::io::Read>, Error>;
}

#[derive(Clone)]
pub struct StdFs;
impl FileSystem for StdFs {
	fn open<P: AsRef<Path>>(&self, path: P) -> Result<Reader, Error> {
		Ok(Box::new(std::fs::File::open(path)?))
	}
}
type Reader = Box<dyn std::io::Read>;

pub struct FileNode<FileSystem> {
	fs: FileSystem,
}
#[node_macro::node_fn(FileNode)]
fn file_node<P: AsRef<Path>, FS: FileSystem>(path: P, fs: FS) -> Result<Reader, Error> {
	fs.open(path)
}

pub struct BufferNode;
#[node_macro::node_fn(BufferNode)]
fn buffer_node<R: std::io::Read>(reader: R) -> Result<Vec<u8>, Error> {
	Ok(std::io::Read::bytes(reader).collect::<Result<Vec<_>, _>>()?)
}

pub struct DownresNode<P> {
	_p: PhantomData<P>,
}

#[node_macro::node_fn(DownresNode<_P>)]
fn downres<_P: Pixel>(image_frame: ImageFrame<_P>) -> ImageFrame<_P> {
	let target_width = (image_frame.transform.transform_vector2((1., 0.).into()).length() as usize).min(image_frame.image.width as usize);
	let target_height = (image_frame.transform.transform_vector2((0., 1.).into()).length() as usize).min(image_frame.image.height as usize);

	let mut image = Image {
		width: target_width as u32,
		height: target_height as u32,
		data: Vec::with_capacity(target_width * target_height),
	};

	let scale_factor = DVec2::new(image_frame.image.width as f64, image_frame.image.height as f64) / DVec2::new(target_width as f64, target_height as f64);
	for y in 0..target_height {
		for x in 0..target_width {
			let pixel = image_frame.sample(DVec2::new(x as f64, y as f64) * scale_factor);
			image.data.push(pixel);
		}
	}

	ImageFrame {
		image,
		transform: image_frame.transform,
	}
}

#[derive(Debug, Clone, Copy)]
pub struct MapImageNode<P, MapFn> {
	map_fn: MapFn,
	_p: PhantomData<P>,
}

#[node_macro::node_fn(MapImageNode<_P>)]
fn map_image<MapFn, _P, Img: RasterMut<Pixel = _P>>(image: Img, map_fn: &'input MapFn) -> Img
where
	MapFn: for<'any_input> Node<'any_input, _P, Output = _P> + 'input,
{
	let mut image = image;

	image.map_pixels(|c| map_fn.eval(c));
	image
}

#[derive(Debug, Clone, DynAny)]
pub struct AxisAlignedBbox {
	start: DVec2,
	end: DVec2,
}

impl AxisAlignedBbox {
	pub fn size(&self) -> DVec2 {
		self.end - self.start
	}

	pub fn to_transform(&self) -> DAffine2 {
		DAffine2::from_translation(self.start) * DAffine2::from_scale(self.size())
	}

	pub fn contains(&self, point: DVec2) -> bool {
		point.x >= self.start.x && point.x <= self.end.x && point.y >= self.start.y && point.y <= self.end.y
	}

	pub fn intersects(&self, other: &AxisAlignedBbox) -> bool {
		other.start.x <= self.end.x && other.end.x >= self.start.x && other.start.y <= self.end.y && other.end.y >= self.start.y
	}

	pub fn union(&self, other: &AxisAlignedBbox) -> AxisAlignedBbox {
		AxisAlignedBbox {
			start: DVec2::new(self.start.x.min(other.start.x), self.start.y.min(other.start.y)),
			end: DVec2::new(self.end.x.max(other.end.x), self.end.y.max(other.end.y)),
		}
	}
	pub fn union_non_empty(&self, other: &AxisAlignedBbox) -> Option<AxisAlignedBbox> {
		match (self.size() == DVec2::ZERO, other.size() == DVec2::ZERO) {
			(true, true) => None,
			(true, _) => Some(other.clone()),
			(_, true) => Some(self.clone()),
			_ => Some(AxisAlignedBbox {
				start: DVec2::new(self.start.x.min(other.start.x), self.start.y.min(other.start.y)),
				end: DVec2::new(self.end.x.max(other.end.x), self.end.y.max(other.end.y)),
			}),
		}
	}
}

#[derive(Debug, Clone)]
struct Bbox {
	top_left: DVec2,
	top_right: DVec2,
	bottom_left: DVec2,
	bottom_right: DVec2,
}

impl Bbox {
	fn axis_aligned_bbox(&self) -> AxisAlignedBbox {
		let start_x = self.top_left.x.min(self.top_right.x).min(self.bottom_left.x).min(self.bottom_right.x);
		let start_y = self.top_left.y.min(self.top_right.y).min(self.bottom_left.y).min(self.bottom_right.y);
		let end_x = self.top_left.x.max(self.top_right.x).max(self.bottom_left.x).max(self.bottom_right.x);
		let end_y = self.top_left.y.max(self.top_right.y).max(self.bottom_left.y).max(self.bottom_right.y);

		AxisAlignedBbox {
			start: DVec2::new(start_x, start_y),
			end: DVec2::new(end_x, end_y),
		}
	}
}

fn compute_transformed_bounding_box(transform: DAffine2) -> Bbox {
	let top_left = DVec2::new(0., 1.);
	let top_right = DVec2::new(1., 1.);
	let bottom_left = DVec2::new(0., 0.);
	let bottom_right = DVec2::new(1., 0.);
	let transform = |p| transform.transform_point2(p);

	Bbox {
		top_left: transform(top_left),
		top_right: transform(top_right),
		bottom_left: transform(bottom_left),
		bottom_right: transform(bottom_right),
	}
}

#[derive(Debug, Clone, Copy)]
pub struct InsertChannelNode<P, S, Insertion, TargetChannel> {
	insertion: Insertion,
	target_channel: TargetChannel,
	_p: PhantomData<P>,
	_s: PhantomData<S>,
}

#[node_macro::node_fn(InsertChannelNode<_P, _S>)]
fn insert_channel_node<
	// _P is the color of the input image.
	_P: RGBMut,
	_S: Pixel + Luminance,
	// Input image
	Input: RasterMut<Pixel = _P>,
	Insertion: Raster<Pixel = _S>,
>(
	mut image: Input,
	insertion: Insertion,
	target_channel: RedGreenBlue,
) -> Input
where
	_P::ColorChannel: Linear,
{
	if insertion.width() == 0 {
		return image;
	}

	if insertion.width() != image.width() || insertion.height() != image.height() {
		log::warn!("Stencil and image have different sizes. This is not supported.");
		return image;
	}

	for y in 0..image.height() {
		for x in 0..image.width() {
			let image_pixel = image.get_pixel_mut(x, y).unwrap();
			let insertion_pixel = insertion.get_pixel(x, y).unwrap();
			match target_channel {
				RedGreenBlue::Red => image_pixel.set_red(insertion_pixel.l().cast_linear_channel()),
				RedGreenBlue::Green => image_pixel.set_green(insertion_pixel.l().cast_linear_channel()),
				RedGreenBlue::Blue => image_pixel.set_blue(insertion_pixel.l().cast_linear_channel()),
			}
		}
	}

	image
}

#[derive(Debug, Clone, Copy)]
pub struct MaskImageNode<P, S, Stencil> {
	stencil: Stencil,
	_p: PhantomData<P>,
	_s: PhantomData<S>,
}

#[node_macro::node_fn(MaskImageNode<_P, _S>)]
fn mask_imge<
	// _P is the color of the input image. It must have an alpha channel because that is going to
	// be modified by the mask
	_P: Copy + Alpha,
	// _S is the color of the stencil. It must have a luminance channel because that is used to
	// mask the input image
	_S: Luminance,
	// Input image
	Input: Transform + RasterMut<Pixel = _P>,
	// Stencil
	Stencil: Transform + Sample<Pixel = _S>,
>(
	mut image: Input,
	stencil: Stencil,
) -> Input {
	let image_size = DVec2::new(image.width() as f64, image.height() as f64);
	let mask_size = stencil.transform().decompose_scale();

	if mask_size == DVec2::ZERO {
		return image;
	}

	// Transforms a point from the background image to the forground image
	let bg_to_fg = image.transform() * DAffine2::from_scale(1. / image_size);
	let stencil_transform_inverse = stencil.transform().inverse();

	let area = bg_to_fg.transform_vector2(DVec2::ONE);
	for y in 0..image.height() {
		for x in 0..image.width() {
			let image_point = DVec2::new(x as f64, y as f64);
			let mut mask_point = bg_to_fg.transform_point2(image_point);
			let local_mask_point = stencil_transform_inverse.transform_point2(mask_point);
			mask_point = stencil.transform().transform_point2(local_mask_point.clamp(DVec2::ZERO, DVec2::ONE));

			let image_pixel = image.get_pixel_mut(x, y).unwrap();
			if let Some(mask_pixel) = stencil.sample(mask_point, area) {
				*image_pixel = image_pixel.multiplied_alpha(mask_pixel.l().cast_linear_channel());
			}
		}
	}

	image
}

#[derive(Debug, Clone, Copy)]
pub struct BlendImageTupleNode<P, Fg, MapFn> {
	map_fn: MapFn,
	_p: PhantomData<P>,
	_fg: PhantomData<Fg>,
}

#[node_macro::node_fn(BlendImageTupleNode<_P, _Fg>)]
fn blend_image_tuple<_P: Alpha + Pixel + Debug, MapFn, _Fg: Sample<Pixel = _P> + Transform>(images: (ImageFrame<_P>, _Fg), map_fn: &'input MapFn) -> ImageFrame<_P>
where
	MapFn: for<'any_input> Node<'any_input, (_P, _P), Output = _P> + 'input + Clone,
{
	let (background, foreground) = images;

	blend_image(foreground, background, map_fn)
}

#[derive(Debug, Clone, Copy)]
pub struct BlendImageNode<P, Background, MapFn> {
	background: Background,
	map_fn: MapFn,
	_p: PhantomData<P>,
}

#[node_macro::node_fn(BlendImageNode<_P>)]
async fn blend_image_node<_P: Alpha + Pixel + Debug, MapFn, Forground: Sample<Pixel = _P> + Transform>(foreground: Forground, background: ImageFrame<_P>, map_fn: &'input MapFn) -> ImageFrame<_P>
where
	MapFn: for<'any_input> Node<'any_input, (_P, _P), Output = _P> + 'input,
{
	blend_new_image(foreground, background, map_fn)
}

#[derive(Debug, Clone, Copy)]
pub struct BlendReverseImageNode<P, Background, MapFn> {
	background: Background,
	map_fn: MapFn,
	_p: PhantomData<P>,
}

#[node_macro::node_fn(BlendReverseImageNode<_P>)]
fn blend_image_node<_P: Alpha + Pixel + Debug, MapFn, Background: Transform + Sample<Pixel = _P>>(foreground: ImageFrame<_P>, background: Background, map_fn: &'input MapFn) -> ImageFrame<_P>
where
	MapFn: for<'any_input> Node<'any_input, (_P, _P), Output = _P> + 'input,
{
	blend_new_image(background, foreground, map_fn)
}

fn blend_new_image<_P: Alpha + Pixel + Debug, MapFn, Frame: Sample<Pixel = _P> + Transform>(foreground: Frame, background: ImageFrame<_P>, map_fn: &MapFn) -> ImageFrame<_P>
where
	MapFn: for<'any_input> Node<'any_input, (_P, _P), Output = _P>,
{
	let foreground_aabb = compute_transformed_bounding_box(foreground.transform()).axis_aligned_bbox();
	let background_aabb = compute_transformed_bounding_box(background.transform()).axis_aligned_bbox();

	let Some(aabb) = foreground_aabb.union_non_empty(&background_aabb) else {return ImageFrame::empty()};

	if background_aabb.contains(foreground_aabb.start) && background_aabb.contains(foreground_aabb.end) {
		return blend_image(foreground, background, map_fn);
	}

	// Clamp the foreground image to the background image
	let start = aabb.start.as_uvec2();
	let end = aabb.end.as_uvec2();

	let new_background = Image::new(end.x - start.x, end.y - start.y, _P::TRANSPARENT);
	let size = DVec2::new(new_background.width as f64, new_background.height as f64);
	let transfrom = DAffine2::from_scale_angle_translation(size, 0., start.as_dvec2());
	let mut new_background = ImageFrame {
		image: new_background,
		transform: transfrom,
	};

	new_background = blend_image(background, new_background, map_fn);
	blend_image(foreground, new_background, map_fn)
}

fn blend_image<_P: Alpha + Pixel + Debug, MapFn, Frame: Sample<Pixel = _P> + Transform, Background: RasterMut<Pixel = _P> + Transform + Sample<Pixel = _P>>(
	foreground: Frame,
	mut background: Background,
	map_fn: &MapFn,
) -> Background
where
	MapFn: for<'any_input> Node<'any_input, (_P, _P), Output = _P>,
{
	let background_size = DVec2::new(background.width() as f64, background.height() as f64);
	// Transforms a point from the background image to the forground image
	let bg_to_fg = background.transform() * DAffine2::from_scale(1. / background_size);

	// Footprint of the foreground image (0,0) (1, 1) in the background image space
	let bg_aabb = compute_transformed_bounding_box(background.transform().inverse() * foreground.transform()).axis_aligned_bbox();

	// Clamp the foreground image to the background image
	let start = (bg_aabb.start * background_size).max(DVec2::ZERO).as_uvec2();
	let end = (bg_aabb.end * background_size).min(background_size).as_uvec2();

	let area = bg_to_fg.transform_point2(DVec2::new(1., 1.)) - bg_to_fg.transform_point2(DVec2::ZERO);
	for y in start.y..end.y {
		for x in start.x..end.x {
			let bg_point = DVec2::new(x as f64, y as f64);
			let fg_point = bg_to_fg.transform_point2(bg_point);

			if let Some(src_pixel) = foreground.sample(fg_point, area) {
				if let Some(dst_pixel) = background.get_pixel_mut(x, y) {
					*dst_pixel = map_fn.eval((src_pixel, *dst_pixel));
				}
			}
		}
	}

	background
}

#[derive(Debug, Clone, Copy)]
pub struct ExtendImageNode<Background> {
	background: Background,
}

#[node_macro::node_fn(ExtendImageNode)]
fn extend_image_node(foreground: ImageFrame<Color>, background: ImageFrame<Color>) -> ImageFrame<Color> {
	let foreground_aabb = compute_transformed_bounding_box(foreground.transform()).axis_aligned_bbox();
	let background_aabb = compute_transformed_bounding_box(background.transform()).axis_aligned_bbox();

	if foreground_aabb.contains(background_aabb.start) && foreground_aabb.contains(background_aabb.end) {
		return foreground;
	}

	blend_image(foreground, background, &BlendNode::new(CopiedNode::new(BlendMode::Normal), CopiedNode::new(100.)))
}

#[derive(Clone, Debug, PartialEq)]
pub struct MergeBoundingBoxNode<Data> {
	_data: PhantomData<Data>,
}

#[node_macro::node_fn(MergeBoundingBoxNode<_Data>)]
fn merge_bounding_box_node<_Data: Transform>(input: (Option<AxisAlignedBbox>, _Data)) -> Option<AxisAlignedBbox> {
	let (initial_aabb, data) = input;

	let snd_aabb = compute_transformed_bounding_box(data.transform()).axis_aligned_bbox();

	if let Some(fst_aabb) = initial_aabb {
		fst_aabb.union_non_empty(&snd_aabb)
	} else {
		Some(snd_aabb)
	}
}

#[derive(Clone, Debug, PartialEq)]
pub struct EmptyImageNode<P, FillColor> {
	pub color: FillColor,
	_p: PhantomData<P>,
}

#[node_macro::node_fn(EmptyImageNode<_P>)]
fn empty_image<_P: Pixel>(transform: DAffine2, color: _P) -> ImageFrame<_P> {
	let width = transform.transform_vector2(DVec2::new(1., 0.)).length() as u32;
	let height = transform.transform_vector2(DVec2::new(0., 1.)).length() as u32;

	let image = Image::new(width, height, color);
	ImageFrame { image, transform }
}

#[derive(Debug, Clone, Copy)]
pub struct ImaginateNode<P, E> {
	cached: E,
	_p: PhantomData<P>,
}

#[node_macro::node_fn(ImaginateNode<_P>)]
fn imaginate<_P: Pixel>(image_frame: ImageFrame<_P>, cached: Option<std::sync::Arc<graphene_core::raster::Image<_P>>>) -> ImageFrame<_P> {
	let cached_image = cached.map(|mut x| std::sync::Arc::make_mut(&mut x).clone()).unwrap_or(image_frame.image);
	ImageFrame {
		image: cached_image,
		transform: image_frame.transform,
	}
}

#[derive(Debug, Clone, Copy)]
pub struct ImageFrameNode<P, Transform> {
	transform: Transform,
	_p: PhantomData<P>,
}
#[node_macro::node_fn(ImageFrameNode<_P>)]
fn image_frame<_P: Pixel>(image: Image<_P>, transform: DAffine2) -> graphene_core::raster::ImageFrame<_P> {
	graphene_core::raster::ImageFrame { image, transform }
}
#[cfg(test)]
mod test {

	#[test]
	fn load_image() {
		// TODO: reenable this test
		/*
		let image = image_node::<&str>();

		let grayscale_picture = image.then(MapResultNode::new(&image));
		let export = export_image_node();

		let picture = grayscale_picture.eval("test-image-1.png").expect("Failed to load image");
		export.eval((picture, "test-image-1-result.png")).unwrap();
		*/
	}
}