use itertools::Itertools;

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

use land2d::Land2D;

use LandGenerationParameters;

use LandGenerator;

struct OutlinePoints {

    islands: Vec<Vec<Point>>,

    fill_points: Vec<Point>,

    size: Size,

}

impl OutlinePoints {

    fn from_outline_template<I: Iterator<Item = u32>>(

        outline_template: &OutlineTemplate,

        random_numbers: &mut I,

    ) -> Self {

        Self {

            islands: outline_template

                .islands

                .iter()

                .map(|i| {

                    i.iter()

                        .zip(random_numbers.tuples())

                        .map(|(rect, (rnd_a, rnd_b))| {

                            Point::new(

                                rect.x + (rnd_a % rect.width) as i32,

                                rect.y + (rnd_b % rect.height) as i32,

                            )

                        }).collect()

                }).collect(),

            fill_points: outline_template.fill_points.clone(),

            size: outline_template.size,

        }

    }

    fn total_len(&self) -> usize {

        self.islands.iter().map(|i| i.len()).sum::<usize>() + self.fill_points.len()

    }

    fn iter_mut(&mut self) -> impl Iterator<Item = &mut Point> {

        self.islands

            .iter_mut()

            .flat_map(|i| i.iter_mut())

            .chain(self.fill_points.iter_mut())

    }

    fn divide_edge<I: Iterator<Item = u32>>(

        &self,

        start_point: Point,

        end_point: Point,

        random_numbers: &mut I,

    ) -> Option<Point> {

        None

    }

    fn divide_edges<I: Iterator<Item = u32>>(&mut self, random_numbers: &mut I) {

        for is in 0..self.islands.len() {

            let mut i = 0;

                if let Some(new_point) = self.divide_edge(start_point, end_point, random_numbers) {

                    i += 2;

                } else {

                    i += 1;

                }

            }

        }

    }

    fn bezierize(&mut self) {

        unimplemented!()

    }

    fn distort<I: Iterator<Item = u32>>(&mut self, random_numbers: &mut I) {

        loop {

            let old_len = self.total_len();

            self.divide_edges(random_numbers);

            if self.total_len() != old_len {

                break;

            }

        }

        self.bezierize();

    }

    fn draw<T: Copy + PartialEq>(&self, land: &mut Land2D<T>, value: T) {

        for island in &self.islands {

            if island.len() > 1 {

                for i in 0..island.len() - 1 {

                    land.draw_line(island[i], island[i + 1], value);

                }

                land.draw_line(island[island.len() - 1], island[0], value);

            }

        }

    }

}

pub struct OutlineTemplate {

    islands: Vec<Vec<Rect>>,

    fill_points: Vec<Point>,

    size: Size,

    can_flip: bool,

    can_invert: bool,

    can_mirror: bool,

    is_negative: bool,

}

impl OutlineTemplate {

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

        OutlineTemplate {

            size,

            islands: Vec::new(),

            fill_points: Vec::new(),

            can_flip: false,

            can_invert: false,

            can_mirror: false,

            is_negative: false,

        }

    }

    pub fn flippable(self) -> Self {

        Self {

            can_flip: true,

            ..self

        }

    }

    pub fn mirrorable(self) -> Self {

        Self {

            can_mirror: true,

            ..self

        }

    }

    pub fn invertable(self) -> Self {

        Self {

            can_invert: true,

            ..self

        }

    }

    pub fn negative(self) -> Self {

        Self {

            is_negative: true,

            ..self

        }

    }

    pub fn with_fill_points(self, fill_points: Vec<Point>) -> Self {

        Self {

            fill_points,

            ..self

        }

    }

    pub fn with_islands(self, islands: Vec<Vec<Rect>>) -> Self {

        Self { islands, ..self }

    }

    pub fn add_fill_points(mut self, points: &[Point]) -> Self {

        self.fill_points.extend_from_slice(points);

        self

    }

    pub fn add_island(mut self, island: &[Rect]) -> Self {

        self.islands.push(island.into());

        self

    }

}

pub struct TemplatedLandGenerator {

    outline_template: OutlineTemplate,

}

impl TemplatedLandGenerator {

    pub fn new(outline_template: OutlineTemplate) -> Self {

        Self { outline_template }

    }

}

impl LandGenerator for TemplatedLandGenerator {

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

        &self,

        parameters: LandGenerationParameters<T>,

        random_numbers: &mut I,

    ) -> Land2D<T> {

        let mut points =

            OutlinePoints::from_outline_template(&self.outline_template, random_numbers);

        let mut land = Land2D::new(points.size, parameters.basic);

        let top_left = Point::new(

            (land.width() - land.play_width() / 2) as i32,

            (land.height() - land.play_height()) as i32,

        );

        points.size = land.size();

        points.iter_mut().for_each(|p| *p += top_left);

        // mirror

        if self.outline_template.can_mirror {

            if let Some(b) = random_numbers.next() {

                if b & 1 != 0 {

                    points

                        .iter_mut()

                        .for_each(|p| p.x = land.width() as i32 - 1 - p.x);

                }

            }

        }

        // flip

        if self.outline_template.can_flip {

            if let Some(b) = random_numbers.next() {

                if b & 1 != 0 {

                    points

                        .iter_mut()

                        .for_each(|p| p.y = land.height() as i32 - 1 - p.y);

                }

            }

        }

        points.distort(random_numbers);

        points.draw(&mut land, parameters.zero);

        for p in &points.fill_points {

            land.fill(*p, parameters.zero, parameters.zero)

        }

        points.draw(&mut land, parameters.basic);

        land

    }

}

#[test()]

fn points_test() {

    let mut points = OutlinePoints {

        islands: vec![vec![]],

        fill_points: vec![Point::new(1, 1)],

        size: Size::square(100),

    };

    points.iter_mut().for_each(|p| p.x = 2);

    assert_eq!(points.fill_points[0].x, 2);

}