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

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

use crate::{LandGenerationParameters, LandGenerator};

use integral_geometry::Size;

use png::Decoder;

use rand::Rng;

use std::collections::HashSet;

use std::fs::File;

use std::io::{BufReader, Result};

use std::path::{Path, PathBuf};

#[derive(Debug, Clone)]

pub struct EdgeDescription {

    pub name: String,

    pub reversed: Option<bool>,

    pub symmetrical: Option<bool>,

}

#[derive(Debug, Clone)]

pub struct EdgesDescription {

    pub top: EdgeDescription,

    pub right: EdgeDescription,

    pub bottom: EdgeDescription,

    pub left: EdgeDescription,

}

#[derive(Debug, Clone)]

pub struct TileDescription {

    pub name: String,

    pub weight: u8,

    pub edges: EdgesDescription,

    pub anti_match: Option<[u64; 4]>,

    pub is_negative: Option<bool>,

    pub can_flip: Option<bool>,

    pub can_mirror: Option<bool>,

    pub can_rotate90: Option<bool>,

    pub can_rotate180: Option<bool>,

    pub can_rotate270: Option<bool>,

}

#[derive(Debug, Clone)]

pub struct ComplexEdgeDescription {

    pub begin: Option<EdgeDescription>,

    pub fill: Option<EdgeDescription>,

    pub end: Option<EdgeDescription>,

}

#[derive(Debug, Clone)]

pub struct NonStrictComplexEdgesDescription {

    pub top: Option<ComplexEdgeDescription>,

    pub right: Option<ComplexEdgeDescription>,

    pub bottom: Option<ComplexEdgeDescription>,

    pub left: Option<ComplexEdgeDescription>,

}

#[derive(Debug, Clone)]

pub struct TemplateDescription {

    pub size: Size,

    pub tiles: Vec<TileDescription>,

    pub edges: NonStrictComplexEdgesDescription,

    pub can_invert: bool,

    pub is_negative: bool,

    pub wrap: bool,

}

pub struct WavefrontCollapseLandGenerator {

    pub template: TemplateDescription,

    data_path: PathBuf,

}

impl WavefrontCollapseLandGenerator {

    pub fn new(template: TemplateDescription, data_path: &Path) -> Self {

        Self {

            template,

            data_path: data_path.to_owned(),

        }

    }

    fn load_image_tiles<T: Copy + PartialEq + Default>(

        &self,

        parameters: &LandGenerationParameters<T>,

        tile_description: &TileDescription,

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

        let mut result = Vec::new();

        let file = File::open(

            self.data_path

                .join("Tiles")

                .join(&tile_description.name)

                .as_path(),

        )?;

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

        let mut reader = decoder.read_info()?;

        let info = reader.info();

        let mut tiles_image =

            vec2d::Vec2D::new(&Size::new(info.width, info.height), parameters.zero);

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

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

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

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

        let (zero, basic) = if tile_description.is_negative.unwrap_or_default() {

            (parameters.basic(), parameters.zero())

        } else {

            (parameters.zero(), parameters.basic())

        };

        match info.color_type.samples() {

            1 => {

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

                    for value in line.iter() {

                        *tiles_image_pixels

                            .next()

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

                            if *value == 0 { zero } else { basic };

                    }

                }

            }

            a => {

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

                    for value in line.chunks_exact(a) {

                        *tiles_image_pixels

                            .next()

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

                            if value[0] == 0u8 { zero } else { basic };

                    }

                }

            }

        }

        let edge_set: EdgeSet<String> = EdgeSet::new([

            (&tile_description.edges.top).into(),

            (&tile_description.edges.right).into(),

            (&tile_description.edges.bottom).into(),

            (&tile_description.edges.left).into(),

        ]);

        let tile = TileImage::<T, String>::new(

            tiles_image,

            tile_description.weight,

            edge_set,

            tile_description.anti_match.unwrap_or_default(),

        );

        result.push(tile.clone());

        if tile_description.can_flip.unwrap_or_default() {

            result.push(tile.flipped());

        }

        if tile_description.can_mirror.unwrap_or_default() {

            result.push(tile.mirrored());

        }

        if tile_description.can_flip.unwrap_or_default()

            && tile_description.can_mirror.unwrap_or_default()

        {

            result.push(tile.mirrored().flipped());

        }

        if tile_description.can_rotate90.unwrap_or_default() {

            result.push(tile.rotated90());

        }

        if tile_description.can_rotate180.unwrap_or_default() {

            result.push(tile.rotated180());

        }

        if tile_description.can_rotate270.unwrap_or_default() {

            result.push(tile.rotated270());

        }

        Ok(result)

    }

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

        &self,

        parameters: &LandGenerationParameters<T>,

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

        let mut result = Vec::new();

        for tile_description in self.template.tiles.iter() {

            if let Ok(mut tiles) = self.load_image_tiles(parameters, tile_description) {

                result.append(&mut tiles);

            } else {

                eprintln!("Failed to load a tile!");

            }

        }

        result

    }

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

        &self,

        tiles: &[TileImage<T, String>],

        probability_distribution_factor: i32,

    ) -> Vec<CollapseRule> {

        let [grid_top_edge, grid_right_edge, grid_bottom_edge, grid_left_edge]: [Option<

            [Option<Edge<String>>; 3],

        >; 4] = [

            self.template.edges.top.as_ref(),

            self.template.edges.right.as_ref(),

            self.template.edges.bottom.as_ref(),

            self.template.edges.left.as_ref(),

        ]

        .map(|opt| opt.map(|d| [&d.begin, &d.fill, &d.end].map(|e| e.as_ref().map(Into::into))));

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

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

            let iteration = [

                (&grid_top_edge, tile.edge_set().top(), &mut top),

                (&grid_right_edge, tile.edge_set().right(), &mut right),

                (&grid_bottom_edge, tile.edge_set().bottom(), &mut bottom),

                (&grid_left_edge, tile.edge_set().left(), &mut left),

            ];

            // compatibility with grid edges

            for (edge, tile_edge, set) in iteration {

                for (is_compatible, tile) in edge

                    .as_ref()

                    .map(|e| {

                        e.clone().map(|ed| {

                            ed.as_ref()

                                .map(|e| e.is_compatible(tile_edge))

                                .unwrap_or(true)

                        })

                    })

                    .unwrap_or([true, true, true])

                    .into_iter()

                    .zip([Tile::OutsideBegin, Tile::OutsideFill, Tile::OutsideEnd].into_iter())

                {

                    if is_compatible {

                        set.insert(tile);

                    }

                }

            }

            // compatibility with itself

            if tile.is_compatible(&tile, MatchSide::OnLeft) {

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

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

            }

            if tile.is_compatible(&tile, MatchSide::OnTop) {

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

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

            }

            // compatibility with previously defined tiles

            for p in 0..i {

                // Check left edge

                if tiles[p].is_compatible(&tile, MatchSide::OnLeft) {

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

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

                }

                // Check right edge

                if tiles[p].is_compatible(&tile, MatchSide::OnRight) {

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

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

                }

                // Check top edge

                if tiles[p].is_compatible(&tile, MatchSide::OnTop) {

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

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

                }

                // Check bottom edge

                if tiles[p].is_compatible(&tile, MatchSide::OnBottom) {

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

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

                }

            }

            let weight = (probability_distribution_factor * 2 * i as i32 / (tiles.len() - 1) as i32

                + 100

                - probability_distribution_factor) as u32;

            rules.push(CollapseRule {

                weight: weight * tile.weight as u32,

                tile: Tile::Numbered(i),

                top,

                right,

                bottom,

                left,

            });

        }

        rules

    }

}

impl LandGenerator for WavefrontCollapseLandGenerator {

    fn generate_land<T: Copy + PartialEq + Default>(

        &self,

        parameters: &LandGenerationParameters<T>,

        random_numbers: &mut impl Rng,

    ) -> land2d::Land2D<T> {

        assert!(parameters.distance_divisor >= 1);

        assert!(parameters.distance_divisor <= 25);

        let tiles = self.load_template(parameters);

        let distribution_factor = (parameters.distance_divisor - 1) as i32 * 8 - 96;

        let rules = self.build_rules(&tiles, distribution_factor);

        let mut wfc = WavefrontCollapse::new(self.template.wrap);

        wfc.set_rules(rules);

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

            let tile_size = first_tile.size();

            Size::new(

                self.template.size.width / tile_size.width,

                self.template.size.height / tile_size.height,

            )

        } else {

            Size::new(1, 1)

        };

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

        // render tiles into resulting land array

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

        let offset_y = result.height() - result.play_height() as usize;

        let offset_x = (result.width() - result.play_width() as usize) / 2;

        for row in 0..wfc_size.height as usize {

            for column in 0..wfc_size.width as usize {

                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 as usize {

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

                            result.map(

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

                                (column * tile.size().width as usize + tile_column + offset_x)

                                    as i32,

                                |p| {

                                    *p =

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

                                },

                            );

                        }

                    }

                } else {

                    // couldn't find a tile to place here, dump some debug info for tile set maker

                    let mut edges = ["-", "|", "-", "|"].map(|s| s.to_owned());

                    if row > 0 {

                        let tile = wfc.grid().get(row - 1, column);

                        edges[0] = if let Some(Tile::Numbered(tile_index)) = tile {

                            tiles[*tile_index].edge_set().bottom().name()

                        } else {

                            format!("{:?}", tile.unwrap())

                        }

                    }

                    if column < wfc_size.width as usize - 1 {

                        let tile = wfc.grid().get(row, column + 1);

                        edges[1] = if let Some(Tile::Numbered(tile_index)) = tile {

                            tiles[*tile_index].edge_set().left().name()

                        } else {

                            format!("{:?}", tile.unwrap())

                        }

                    }

                    if row < wfc_size.height as usize - 1 {

                        let tile = wfc.grid().get(row + 1, column);

                        edges[2] = if let Some(Tile::Numbered(tile_index)) = tile {

                            tiles[*tile_index].edge_set().top().name()

                        } else {

                            format!("{:?}", tile.unwrap())

                        }

                    }

                    if column > 0 {

                        let tile = wfc.grid().get(row, column - 1);

                        edges[3] = if let Some(Tile::Numbered(tile_index)) = tile {

                            tiles[*tile_index].edge_set().right().name()

                        } else {

                            format!("{:?}", tile.unwrap())

                        }

                    }

                    eprintln!(

                        "Couldn't find a tile to place here (row, column): ({}, {}), edges are: [{}]",

                        row, column, edges.join(", "),

                    );

                }

            }

        }

        result

    }

}

impl From<&EdgeDescription> for Edge<String> {

    fn from(val: &EdgeDescription) -> Self {

        if val.reversed.unwrap_or_default() {

            edge.reversed()

        } else {

            edge

        }

    }

}

impl<T: AsRef<str>> From<T> for EdgeDescription {

    fn from(val: T) -> Self {

        use std::cmp::Ordering;

            Ordering::Less => EdgeDescription {

                symmetrical: Some(false),

                reversed: Some(false),

            },

            Ordering::Equal => EdgeDescription {

                name: reversed,

                symmetrical: Some(true),

                reversed: Some(false),

            },

            Ordering::Greater => EdgeDescription {

                name: reversed,

                symmetrical: Some(false),

                reversed: Some(true),

            },

        }

    }

}