use super::tile_image::{Edge, TileImage};

use super::wavefront_collapse::{CollapseRule, Tile, WavefrontCollapse};

use crate::{LandGenerationParameters, LandGenerator};

use integral_geometry::Size;

use png::Decoder;

use std::collections::HashSet;

use std::fs::File;

use std::io::BufReader;

pub struct WavefrontCollapseLandGenerator {

    pub size: Size,

}

impl WavefrontCollapseLandGenerator {

    pub fn new(size: &Size) -> Self {

        Self { size: *size }

    }

    pub fn load_template<T: Copy + PartialEq + Default>(

        &self,

        parameters: &LandGenerationParameters<T>,

    ) -> Vec<TileImage<T, String>> {

        let mut result = Vec::new();

        let file = File::open("sample.png").expect("file exists");

        let decoder = Decoder::new(BufReader::new(file));

        let mut reader = decoder.read_info().unwrap();

        let info = reader.info();

        let mut tiles_image = vec2d::Vec2D::new(

            &Size::new(info.width as usize, info.height as usize),

            parameters.zero,

        );

        let mut buf = vec![0; reader.output_buffer_size()];

        let info = reader.next_frame(&mut buf).unwrap();

        let bytes = &buf[..info.buffer_size()];

        let mut tiles_image_pixels = tiles_image.as_mut_slice().into_iter();

        for line in bytes.chunks_exact(info.line_size) {

            for value in line.chunks_exact(info.color_type.samples()) {

                *tiles_image_pixels

                    .next()

                    .expect("vec2d size matching image dimensions") =

                    if value.into_iter().all(|p| *p == 0) {

                        parameters.zero

                    } else {

                        parameters.basic

                    };

            }

        }

        let top_edge = Edge::new("ef".to_owned(), false);

        let right_edge = top_edge.reversed();

        let bottom_edge = Edge::new("ee".to_owned(), true);

        let left_edge = bottom_edge.clone();

        let tile =

            TileImage::<T, String>::new(tiles_image, top_edge, right_edge, bottom_edge, left_edge);

        result.push(tile.clone());

        result.push(tile.rotated90());

        result.push(tile.rotated180());

        result.push(tile.rotated270());

        result

    }

}

impl LandGenerator for WavefrontCollapseLandGenerator {

    fn generate_land<T: Copy + PartialEq + Default, I: Iterator<Item = u32>>(

        &self,

        parameters: &LandGenerationParameters<T>,

        random_numbers: &mut I,

    ) -> land2d::Land2D<T> {

        let tiles = self.load_template(parameters);

        let mut rules = Vec::<CollapseRule>::new();

        let default_connection = HashSet::from_iter(vec![Tile::Outside, Tile::Empty].into_iter());

        for (i, tile) in tiles.iter().enumerate() {

            let mut right = default_connection.clone();

            let mut bottom = default_connection.clone();

            let mut left = default_connection.clone();

            let mut top = default_connection.clone();

            for p in 0..i {

                if tiles[p].left_edge().is_compatible(tile.right_edge()) {

                    rules[p].left.insert(Tile::Numbered(i));

                    right.insert(Tile::Numbered(p));

                }

                if tiles[p].right_edge().is_compatible(tile.left_edge()) {

                    rules[p].right.insert(Tile::Numbered(i));

                    left.insert(Tile::Numbered(p));

                }

                if tiles[p].top_edge().is_compatible(tile.bottom_edge()) {

                    rules[p].top.insert(Tile::Numbered(i));

                    bottom.insert(Tile::Numbered(p));

                }

                if tiles[p].bottom_edge().is_compatible(tile.top_edge()) {

                    rules[p].bottom.insert(Tile::Numbered(i));

                    top.insert(Tile::Numbered(p));

                }

            }

            rules.push(CollapseRule {

                tile: Tile::Numbered(i),

                top,

                right,

                bottom,

                left,

            });

        }

        let mut wfc = WavefrontCollapse::default();

        wfc.set_rules(rules);

        let wfc_size = if let Some(first_tile) = tiles.first() {

            let tile_size = first_tile.size();

            Size::new(

                self.size.width / tile_size.width,

                self.size.height / tile_size.height,

            )

        } else {

            Size::new(1, 1)

        };

        wfc.generate_map(&wfc_size, |_| {}, random_numbers);

        let grid = wfc.grid();

        for r in 0..grid.height() {

            for c in 0..grid.width() {

            }

            println!();

        }

        let mut result = land2d::Land2D::new(&self.size, parameters.zero);

        for row in 0..wfc_size.height {

            for column in 0..wfc_size.width {

                if let Some(Tile::Numbered(tile_index)) = wfc.grid().get(row, column) {

                    let tile = &tiles[*tile_index];

                    for tile_row in 0..tile.size().height {

                        for tile_column in 0..tile.size().width {

                            result.map(

                                (row * tile.size().height + tile_row) as i32,

                                (column * tile.size().width + tile_column) as i32,

                                |p| {

                                    *p =

                                        *tile.get(tile_row, tile_column).unwrap_or(&parameters.zero)

                                },

                            );

                        }

                    }

                }

            }

        }

        result

    }

}

#[cfg(test)]

mod tests {

    use super::WavefrontCollapseLandGenerator;

    use crate::{LandGenerationParameters, LandGenerator};

    use integral_geometry::Size;

    use std::fs::File;

    use std::io::BufWriter;

    use std::path::Path;

    use vec2d::Vec2D;

    #[test]

    fn test_generation() {

        let wfc_gen = WavefrontCollapseLandGenerator::new(&Size::new(2048, 1024));

        let landgen_params = LandGenerationParameters::new(0u32, 0xff000000u32, 0, true, true);

        let path = Path::new(r"output.png");

        let file = File::create(path).unwrap();

        let ref mut w = BufWriter::new(file);

        let mut encoder = png::Encoder::new(w, land.width() as u32, land.height() as u32); // Width is 2 pixels and height is 1.

        encoder.set_color(png::ColorType::Rgba);

        encoder.set_depth(png::BitDepth::Eight);

        encoder.set_source_gamma(png::ScaledFloat::from_scaled(45455)); // 1.0 / 2.2, scaled by 100000

        encoder.set_source_gamma(png::ScaledFloat::new(1.0 / 2.2)); // 1.0 / 2.2, unscaled, but rounded

        let source_chromaticities = png::SourceChromaticities::new(

            // Using unscaled instantiation here

            (0.31270, 0.32900),

            (0.64000, 0.33000),

            (0.30000, 0.60000),

            (0.15000, 0.06000),

        );

        encoder.set_source_chromaticities(source_chromaticities);

        let mut writer = encoder.write_header().unwrap();

        writer.write_image_data(land.raw_pixel_bytes()).unwrap(); // Save

    }

}