use itertools::Itertools;

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

use land2d::Land2D;

use outline_template::OutlineTemplate;

pub struct OutlinePoints {

    pub islands: Vec<Vec<Point>>,

    pub fill_points: Vec<Point>,

    pub size: Size,

}

impl OutlinePoints {

    pub 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,

        }

    }

    pub fn total_len(&self) -> usize {

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

    }

    pub 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,

        segment: Line,

        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;

            let mut segment;

            loop {

                {

                    let island = &self.islands[is];

                    let mut end_point;

                    if i < island.len() {

                        end_point = if i + 1 < island.len() {

                            island[i + 1]

                        } else {

                            island[0]

                        };

                    } else {

                        break;

                    }

                    segment = Line::new(island[i], end_point);

                }

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

                    self.islands[is].insert(i + 1, new_point);

                    i += 2;

                } else {

                    i += 1;

                }

            }

        }

    }

    pub fn bezierize(&mut self) {

        unimplemented!()

    }

    pub 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();

    }

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

        for segment in self.segments_iter() {

            land.draw_line(segment, value);

        }

    }

    fn segments_iter(&self) -> OutlineSegmentsIterator {

        OutlineSegmentsIterator {

            outline: self,

            island: 0,

            index: 0,

        }

    }

}

struct OutlineSegmentsIterator<'a> {

    outline: &'a OutlinePoints,

    island: usize,

    index: usize,

}

impl<'a> Iterator for OutlineSegmentsIterator<'a> {

    type Item = Line;

    fn next(&mut self) -> Option<Self::Item> {

        if self.island < self.outline.islands.len() {

            if self.index + 1 < self.outline.islands[self.index].len() {

                Some(Line::new(

                    self.outline.islands[self.index][self.index],

                    self.outline.islands[self.index][self.index + 1],

                ))

            } else if self.index + 1 == self.outline.islands[self.index].len() {

                Some(Line::new(

                    self.outline.islands[self.index][self.index],

                    self.outline.islands[self.index][0],

                ))

            } else {

                self.island += 1;

                self.next()

            }

        } else {

            None

        }

    }

}