mod template;

pub mod theme;

use self::theme::Theme;

use crate::template::outline::TemplateCollectionDesc as OutlineTemplateCollectionDesc;

use crate::template::wavefront_collapse::TemplateCollectionDesc as WfcTemplateCollectionDesc;

use land2d::Land2D;

use landgen::{

    outline_template_based::{

        outline_template::OutlineTemplate, template_based::TemplatedLandGenerator,

    },

    wavefront_collapse::generator::{

        TemplateDescription as WfcTemplate, WavefrontCollapseLandGenerator,

    },

    LandGenerationParameters, LandGenerator,

};

use rand::{seq::SliceRandom, Rng};

use std::{borrow::Borrow, collections::hash_map::HashMap};

use vec2d::Vec2D;

#[derive(PartialEq, Eq, Hash, Clone, Debug)]

struct TemplateType(String);

impl Borrow<str> for TemplateType {

    fn borrow(&self) -> &str {

        self.0.as_str()

    }

}

#[derive(Debug)]

pub struct MapGenerator<T> {

    pub(crate) templates: HashMap<TemplateType, Vec<T>>,

}

impl<T> MapGenerator<T> {

    pub fn new() -> Self {

        Self {

            templates: HashMap::new(),

        }

    }

    pub fn get_template<R: Rng>(&self, template_type: &str, rng: &mut R) -> Option<&T> {

        self.templates

            .get(template_type)

            .and_then(|t| t.as_slice().choose(rng))

    }

    pub fn make_texture<LandT>(

        &self,

        land: &Land2D<LandT>,

        parameters: &LandGenerationParameters<LandT>,

        theme: &Theme,

    ) -> Vec2D<u32>

    where

        LandT: Copy + Default + PartialEq,

    {

        let mut texture = Vec2D::new(&land.size().size(), 0);

        if let Some(land_sprite) = theme.land_texture() {

            for (row_index, (land_row, tex_row)) in land.rows().zip(texture.rows_mut()).enumerate()

            {

                let sprite_row = land_sprite.get_row(row_index % land_sprite.height());

                let mut x_offset = 0;

                while sprite_row.len() < land.width() - x_offset {

                    let copy_range = x_offset..x_offset + sprite_row.len();

                    tex_row_copy(

                        parameters.basic(),

                        &land_row[copy_range.clone()],

                        &mut tex_row[copy_range],

                        sprite_row,

                    );

                    x_offset += land_sprite.width()

                }

                if x_offset < land.width() {

                    let final_range = x_offset..land.width();

                    tex_row_copy(

                        parameters.basic(),

                        &land_row[final_range.clone()],

                        &mut tex_row[final_range],

                        &sprite_row[..land.width() - x_offset],

                    );

                }

            }

        }

        if let Some(border_sprite) = theme.border_texture() {

            assert!(border_sprite.height() <= 512);

            let border_width = (border_sprite.height() / 2) as u8;

            let border_sprite = border_sprite.to_tiled();

            let mut offsets = vec![255u8; land.width()];

            land_border_pass(

                parameters.basic(),

                land.rows().rev().zip(texture.rows_mut().rev()),

                &mut offsets,

                border_width,

                |x, y| {

                    border_sprite

                        .get_pixel(x % border_sprite.width(), border_sprite.height() - 1 - y)

                },

            );

            offsets.iter_mut().for_each(|v| *v = 255);

            land_border_pass(

                parameters.basic(),

                land.rows().zip(texture.rows_mut()),

                &mut offsets,

                border_width,

                |x, y| border_sprite.get_pixel(x % border_sprite.width(), y),

            );

        }

        texture

    }

}

impl MapGenerator<OutlineTemplate> {

    pub fn import_yaml_templates(&mut self, text: &str) {

        let mut desc: OutlineTemplateCollectionDesc = serde_yaml::from_str(text).unwrap();

        let templates = std::mem::take(&mut desc.templates);

        self.templates = desc

            .template_types

            .into_iter()

            .map(|(size, indices)| {

                (

                    TemplateType(size),

                    indices.iter().map(|i| (&templates[*i]).into()).collect(),

                )

            })

            .collect();

    }

    pub fn build_generator(&self, template: OutlineTemplate) -> impl LandGenerator {

        TemplatedLandGenerator::new(template)

    }

}

impl MapGenerator<WfcTemplate> {

    pub fn import_yaml_templates(&mut self, text: &str) {

        let mut desc: WfcTemplateCollectionDesc = serde_yaml::from_str(text).unwrap();

        let templates = std::mem::take(&mut desc.templates);

        self.templates = desc

            .template_types

            .into_iter()

            .map(|(size, indices)| {

                (

                    TemplateType(size),

                    indices.iter().map(|i| (&templates[*i]).into()).collect(),

                )

            })

            .collect();

    }

    pub fn build_generator(&self, template: WfcTemplate) -> impl LandGenerator {

        WavefrontCollapseLandGenerator::new(template)

    }

}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]

struct Color(u32);

impl Color {

    #[inline]

    fn red(self) -> u8 {

        (self.0 & 0xFF) as u8

    }

    #[inline]

    fn green(self) -> u8 {

        (self.0 >> 8 & 0xFF) as u8

    }

    #[inline]

    fn blue(self) -> u8 {

        (self.0 >> 16 & 0xFF) as u8

    }

    #[inline]

    fn alpha(self) -> u8 {

        (self.0 >> 24 & 0xFF) as u8

    }

}

#[inline]

fn lerp(from: u8, to: u8, coef: u8) -> u8 {

    ((from as u16 * (256 - coef as u16) + to as u16 * coef as u16) / 256) as u8

}

#[inline]

fn blend(source: u32, target: u32) -> u32 {

    let source = Color(source);

    let target = Color(target);

    let alpha = lerp(target.alpha(), 255, source.alpha());

    let red = lerp(target.red(), source.red(), source.alpha());

    let green = lerp(target.green(), source.green(), source.alpha());

    let blue = lerp(target.blue(), source.blue(), source.alpha());

    (red as u32) | (green as u32) << 8 | (blue as u32) << 16 | (alpha as u32) << 24

}

fn land_border_pass<'a, LandT, T, F>(

    basic_value: LandT,

    rows: T,

    offsets: &mut [u8],

    border_width: u8,

    pixel_getter: F,

) where

    LandT: Default + PartialEq + 'a,

    T: Iterator<Item = (&'a [LandT], &'a mut [u32])>,

    F: (Fn(usize, usize) -> u32),

{

    for (land_row, tex_row) in rows {

        for (x, ((land_v, tex_v), offset_v)) in land_row

            .iter()

            .zip(tex_row.iter_mut())

            .zip(offsets.iter_mut())

            .enumerate()

        {

            *offset_v = if *land_v == basic_value {

                if *offset_v < border_width {

                    *tex_v = blend(pixel_getter(x, *offset_v as usize), *tex_v)

                }

                offset_v.saturating_add(1)

            } else {

                0

            }

        }

    }

}

fn tex_row_copy<LandT>(

    basic_value: LandT,

    land_row: &[LandT],

    tex_row: &mut [u32],

    sprite_row: &[u32],

) where

    LandT: Default + PartialEq,

{

    for ((land_v, tex_v), sprite_v) in land_row.iter().zip(tex_row.iter_mut()).zip(sprite_row) {

        *tex_v = if *land_v == basic_value { *sprite_v } else { 0 }

    }

}

#[cfg(test)]

mod tests {

    #[test]

    fn simple_load() {

        let text = r#"

# comment

templates:

  -

    width: 3072

    height: 1424

    can_flip: false

    can_invert: false

    can_mirror: true

    is_negative: false

    put_girders: true

    max_hedgehogs: 18

    outline_points:

      -

        - {x: 748, y: 1424, w: 1, h: 1}

        - {x: 636, y: 1252, w: 208, h: 72}

        - {x: 898, y: 1110, w: 308, h: 60}

        - {x: 1128, y: 1252, w: 434, h: 40}

        - {x: 1574, y: 1112, w: 332, h: 40}

        - {x: 1802, y: 1238, w: 226, h: 36}

        - {x: 1930, y: 1424, w: 1, h: 1}

    fill_points:

      - {x: 1023, y: 0}

      - {x: 1023, y: 0}

template_types:

    test: [0]

"#;

        generator.import_yaml_templates(&text);

        assert!(generator

            .templates

            .contains_key(&TemplateType("test".to_string())));

        assert_eq!(template.islands[0].len(), 7);

    }

}