pub mod theme;

use std::{

    collections::hash_map::HashMap,

    borrow::Borrow,

    mem::replace

};

use serde_derive::{Deserialize};

use serde_yaml;

use integral_geometry::{Point, Size, Rect};

use landgen::{

    outline_template::OutlineTemplate

};

use rand::{thread_rng, Rng};

use land2d::Land2D;

use vec2d::Vec2D;

use self::theme::Theme;

#[derive(Deserialize)]

struct PointDesc {

    x: u32,

    y: u32

}

#[derive(Deserialize)]

struct RectDesc {

    x: u32,

    y: u32,

    w: u32,

    h: u32

}

#[derive(Deserialize)]

struct TemplateDesc {

    width: usize,

    height: usize,

    can_flip: bool,

    can_invert: bool,

    can_mirror: bool,

    is_negative: bool,

    put_girders: bool,

    max_hedgehogs: u8,

    outline_points: Vec<Vec<RectDesc>>,

    fill_points: Vec<PointDesc>

}

#[derive(Deserialize)]

struct TemplateCollectionDesc {

    templates: Vec<TemplateDesc>,

    template_types: HashMap<String, Vec<usize>>

}

impl From<&TemplateDesc> for OutlineTemplate {

    fn from(desc: &TemplateDesc) -> Self {

        OutlineTemplate {

            islands: desc.outline_points.iter()

                .map(|v| v.iter()

                    .map(|r| Rect::from_size(

                        Point::new(r.x as i32, r.y as i32),

                        Size::new(r.w as usize, r.h as usize)))

                    .collect())

                .collect(),

            fill_points: desc.fill_points.iter()

                .map(|p| Point::new(p.x as i32, p.y as i32))

                .collect(),

            size: Size::new(desc.width, desc.height),

            can_flip: desc.can_flip,

            can_invert: desc.can_invert,

            can_mirror: desc.can_mirror,

            is_negative: desc.is_negative

        }

    }

}

#[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 {

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

}

impl MapGenerator {

    pub fn new() -> Self {

        Self { templates: HashMap::new() }

    }

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

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

        let templates = replace(&mut desc.templates, vec![]);

        self.templates = desc.template_types.into_iter()

            .map(|(size, indices)|

                (TemplateType(size), indices.iter()

                    .map(|i| (&templates[*i]).into())

                    .collect()))

            .collect();

    }

    pub fn get_template(&self, template_type: &str) -> Option<&OutlineTemplate> {

        self.templates.get(template_type).and_then(|t| thread_rng().choose(t))

    }

    pub fn make_texture(&self, land: &Land2D<u8>, theme: &Theme) -> Vec2D<u32> {

        let mut texture = Vec2D::new(land.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(

                        &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(

                        &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(

                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(

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

                &mut offsets,

                border_width,

                |x, y| border_sprite.get_pixel(

                    x % border_sprite.width(),

                    y,

                )

            );

        }

        texture

    }

}

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

struct Color(u32);

impl Color {

    #[inline]

    fn red(self) -> u8 {

        (self.0 >> 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) << 0 | (green as u32) << 8 | (blue as u32) << 16 | (alpha as u32) << 24

}

fn land_border_pass<'a, T, F>(rows: T, offsets: &mut [u8], border_width: u8, pixel_getter: F)

    where T: Iterator<Item = (&'a [u8], &'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 == 0 {

                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(land_row: &[u8], tex_row: &mut [u32], sprite_row: &[u32]) {

    for ((land_v, tex_v), sprite_v) in

        land_row.iter().zip(tex_row.iter_mut()).zip(sprite_row)

    {

        *tex_v = if *land_v == 0 {

            *sprite_v

        } else {

            0

        }

    }

}

#[cfg(test)]

mod tests {

    use crate::{

        MapGenerator,

        TemplateType

    };

    #[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]

"#;

        let mut generator = MapGenerator::new();

        generator.import_yaml_templates(&text);

        assert!(generator.templates.contains_key(&TemplateType("test".to_string())));

        let template = generator.get_template("test").unwrap();

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

    }

}