use super::{atlas::AtlasCollection, gl::Texture2D};

use crate::render::camera::Camera;

use integral_geometry::{Rect, Size};

use crate::render::atlas::SpriteIndex;

use png::{ColorType, Decoder, DecodingError};

use std::path::PathBuf;

use std::{

    collections::HashMap,

    ffi::OsString,

    fs::{read_dir, File},

    io,

    io::BufReader,

    path::Path,

};

pub struct GearRenderer {

    atlas: AtlasCollection,

}

struct SpriteData {

    size: Size,

    filename: PathBuf,

}

const ATLAS_SIZE: Size = Size::square(2048);

impl GearRenderer {

    pub fn new() -> Self {

        let mut lookup = Vec::with_capacity(2048);

        let mut atlas = AtlasCollection::new(ATLAS_SIZE);

        let mut sprites = load_sprites(Path::new("../../share/hedgewars/Data/Graphics/"))

            .expect("Unable to load Graphics");

        let max_size = sprites

            .iter()

            .fold(Size::EMPTY, |size, sprite| size.join(sprite.size));

        for sprite in sprites.drain(..) {

            lookup.push((sprite.filename, atlas.insert_sprite(sprite.size).unwrap()));

        }

        println!(

            "Filled atlas with {} sprites:\n{}",

            sprites.len(),

            atlas.used_space()

        );

        let texture = Texture2D::new(ATLAS_SIZE, gl::RGBA8, gl::LINEAR);

        let mut pixels = vec![0; max_size.area()].into_boxed_slice();

        let mut pixels_transposed = vec![0; max_size.area()].into_boxed_slice();

        for (path, sprite_index) in lookup.drain(..) {

            if let Some((atlas_index, rect)) = atlas.get_rect(sprite_index) {

                let size = load_sprite_pixels(&path, mapgen::theme::slice_u32_to_u8_mut(&mut pixels[..])).expect("Unable to load Graphics");

                let used_pixels = if size.width != rect.width() {

                    for y in 0..rect.height() {

                        for x in 0..rect.width() {

                            pixels_transposed[y * rect.width() + x] = pixels[x * rect.height() + y];

                        }

                    }

                    &mut pixels_transposed[..]

                } else {

                    &mut pixels[..]

                };

                texture.update(rect, mapgen::theme::slice_u32_to_u8_mut(used_pixels), 0, gl::RGBA, gl::UNSIGNED_BYTE);

            }

        }

        Self { atlas }

    }

    pub fn render(&mut self, camera: &Camera) {

        let projection = camera.projection();

    }

}

fn load_sprite_pixels(path: &Path, buffer: &mut [u8]) -> io::Result<Size> {

    let decoder = Decoder::new(BufReader::new(File::open(path)?));

    let (info, mut reader) = decoder.read_info()?;

    let size = Size::new(info.width as usize, info.height as usize);

    reader.next_frame(buffer)?;

    Ok(size)

}

fn load_sprite_size(path: &Path) -> io::Result<Size> {

    let decoder = Decoder::new(BufReader::new(File::open(path)?));

    let (info, mut reader) = decoder.read_info()?;

    let size = Size::new(info.width as usize, info.height as usize);

    Ok(size)

}

fn load_sprites(path: &Path) -> io::Result<Vec<SpriteData>> {

    let mut result = vec![];

    for file in read_dir(path)? {

        let file = file?;

        if let Some(extension) = file.path().extension() {

            if extension == "png" {

                let path = file.path();

                let sprite = load_sprite_size(&path)?;

                result.push(SpriteData {

                    size: sprite,

                    filename: path,

                });

            }

        }

    }

    Ok(result)

}