use crate::outline_template_based::outline::OutlinePoints;

use crate::{LandGenerationParameters, LandGenerator};

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

use land2d::Land2D;

use rand::Rng;

#[derive(Clone)]

pub struct MazeTemplate {

    pub width: usize,

    pub height: usize,

    pub cell_size: usize,

    pub inverted: bool,

    pub distortion_limiting_factor: u32,

    pub braidness: u32,

}

struct Maze {

    inverted: bool,

    braidness: u32,

    off: Point,

    num_cells: Size,

    num_edges: Size,

    seen_cells: Size,

    cell_size: usize,

    seen_list: Vec<Vec<Option<usize>>>,

    walls: Vec<Vec<Vec<bool>>>,

    edge_list: Vec<Vec<Vec<bool>>>,

    last_cell: Vec<Point>,

    came_from: Vec<Vec<Point>>,

    came_from_pos: Vec<i32>,

}

fn in_line(p1: &Point, p2: &Point, p3: &Point) -> bool {

    p1.x == p2.x && p2.x == p3.x || p1.y == p2.y && p2.y == p3.y

}

#[derive(Clone, Copy)]

struct Direction(Point);

impl Direction {

    #[inline]

    pub fn new(direction: usize) -> Self {

        match direction % 4 {

            0 => Self(Point::new(0, -1)),

            1 => Self(Point::new(1, 0)),

            2 => Self(Point::new(0, 1)),

            3 => Self(Point::new(-1, 0)),

            _ => panic!("Impossible"),

        }

    }

    #[inline]

    pub fn rotate_right(self) -> Self {

        Self(self.0.rotate90())

    }

    #[inline]

    pub fn rotate_left(self) -> Self {

        Self(self.0.rotate270())

    }

    #[inline]

    pub fn to_edge(self) -> Self {

        Self(Point::new(

            if self.0.x < 0 { 0 } else { self.0.x },

            if self.0.y < 0 { 0 } else { self.0.y },

        ))

    }

    #[inline]

    pub fn orientation(&self) -> usize {

        if self.0.x == 0 {

            0

        } else {

            1

        }

    }

}

impl Maze {

    pub fn new(

        size: &Size,

        cell_size: usize,

        num_steps: usize,

        inverted: bool,

        braidness: u32,

        random_numbers: &mut impl Rng,

    ) -> Self {

        let num_cells = Size::new(

            prev_odd(size.width / cell_size),

            prev_odd(size.height / cell_size),

        );

        let num_edges = Size::new(num_cells.width - 1, num_cells.height - 1);

        let seen_cells = Size::new(num_cells.width / 2, num_cells.height / 2);

        let mut last_cell = vec![Point::diag(0); num_steps];

        let came_from_pos = vec![0; num_steps];

        let came_from = vec![vec![Point::diag(0); num_steps]; num_cells.area()];

        let seen_list = vec![vec![None as Option<usize>; seen_cells.width]; seen_cells.height];

        let walls = vec![vec![vec![true; seen_cells.width]; seen_cells.height]; 2];

        let edge_list = vec![vec![vec![false; num_cells.width]; num_cells.height]; 2];

        for current_step in 0..num_steps {

            let x = random_numbers.gen_range(0..seen_cells.width - 1) / num_steps;

            last_cell[current_step] = Point::new(

                (x + current_step * seen_cells.width / num_steps) as i32,

                random_numbers.gen_range(0..seen_cells.height) as i32,

            );

        }

        let off_x = ((size.width - num_cells.width * cell_size) / 2) as i32;

        let off_y = ((size.height - num_cells.height * cell_size) / 2) as i32;

        Self {

            inverted,

            braidness,

            off: Point::new(off_x, off_y),

            num_cells,

            num_edges,

            seen_cells,

            cell_size,

            seen_list,

            walls,

            edge_list,

            last_cell,

            came_from,

            came_from_pos,

        }

    }

    fn see_cell(

        &mut self,

        current_step: usize,

        start_dir: Direction,

        random_numbers: &mut impl Rng,

    ) -> bool {

        let mut dir = start_dir;

        loop {

            let p = self.last_cell[current_step];

            self.seen_list[p.y as usize][p.x as usize] = Some(current_step);

            let next_dir_clockwise = random_numbers.gen();

            for _ in 0..5 {

                let sp = p + dir.0;

                let when_seen = if sp.x < 0

                    || sp.x >= self.seen_cells.width as i32

                    || sp.y < 0

                    || sp.y >= self.seen_cells.height as i32

                {

                    Some(current_step)

                } else {

                    self.seen_list[sp.y as usize][sp.x as usize]

                };

                match when_seen {

                    Some(a) if a == current_step => {

                        // try another direction

                        if !self.inverted && random_numbers.gen_range(0..self.braidness) == 0 {

                            if dir.0.x == -1 && p.x > 0 {

                                self.walls[dir.orientation()][p.y as usize][p.x as usize - 1] =

                                    false;

                            }

                            if dir.0.x == 1 && p.x < self.seen_cells.width as i32 - 1 {

                                self.walls[dir.orientation()][p.y as usize][p.x as usize] = false;

                            }

                            if dir.0.y == -1 && p.y > 0 {

                                self.walls[dir.orientation()][p.y as usize - 1][p.x as usize] =

                                    false;

                            }

                            if dir.0.y == 1 && p.y < self.seen_cells.height as i32 - 1 {

                                self.walls[dir.orientation()][p.y as usize][p.x as usize] = false;

                            }

                        }

                        if next_dir_clockwise {

                            dir = dir.rotate_right();

                        } else {

                            dir = dir.rotate_left();

                        }

                    }

                    None => {

                        // cell was not seen yet, go there

                        let o_dir = dir.rotate_right().rotate_right();

                        let op = p - o_dir.to_edge().0;

                        self.walls[o_dir.orientation()][op.y as usize][op.x as usize] = false;

                        self.last_cell[current_step] = sp;

                        self.came_from_pos[current_step] += 1;

                        self.came_from[self.came_from_pos[current_step] as usize][current_step] = p;

                        return false;

                    }

                    _ => {

                        return true;

                    }

                }

            }

            self.last_cell[current_step] =

                self.came_from[self.came_from_pos[current_step] as usize][current_step];

            self.came_from_pos[current_step] -= 1;

            if self.came_from_pos[current_step] < 0 {

                return true;

            }

        }

    }

    fn add_vertex(&mut self, p: Point, polygon: &mut Vec<Point>) {

        let [x, y] = [p.x, p.y].map(|i| {

            if self.inverted || i & 1 == 0 {

                self.cell_size

            } else {

                self.cell_size * 2 / 3

            }

        });

        let new_point = Point::new(

            (p.x - 1) * self.cell_size as i32 + x as i32 + self.off.x,

            (p.y - 1) * self.cell_size as i32 + y as i32 + self.off.y,

        );

        let nv = polygon.len();

        if nv > 2 {

            if in_line(&polygon[nv - 2], &polygon[nv - 1], &new_point) {

                polygon.pop();

            }

        }

        polygon.push(new_point);

    }

    fn add_edge(&mut self, p: Point, mut dir: Direction, polygon: &mut Vec<Point>) {

        let mut next_p = Some(p);

        while let Some(p) = next_p {

            next_p = None;

            for _ in 0..4 {

                let cdir = dir.to_edge();

                let np = p + cdir.0;

                if np.x >= 0

                    && np.y >= 0

                    && np.x < self.num_cells.width as i32

                    && np.y < self.num_cells.height as i32

                    && self.edge_list[dir.orientation()][np.y as usize][np.x as usize]

                {

                    self.edge_list[dir.orientation()][np.y as usize][np.x as usize] = false;

                    self.add_vertex(p + dir.0 + Point::new(1, 1), polygon);

                    next_p = Some(p + dir.0);

                    break;

                }

                dir = dir.rotate_right();

            }

        }

    }

    pub fn to_islands(mut self) -> (Vec<Polygon>, Vec<Point>) {

        let mut islands: Vec<Polygon> = vec![];

        let mut polygon: Vec<Point> = vec![];

        let mut maze = vec![vec![false; self.num_cells.width]; self.num_cells.height];

        for x in 0..self.seen_cells.width {

            for y in 0..self.seen_cells.height {

                if self.seen_list[y][x].is_some() {

                    maze[y * 2 + 1][x * 2 + 1] = true;

                }

            }

            for y in 0..self.seen_cells.height - 1 {

                if !self.walls[0][y][x] {

                    maze[y * 2 + 2][x * 2 + 1] = true;

                }

            }

        }

        for x in 0..self.seen_cells.width - 1 {

            for y in 0..self.seen_cells.height {

                if !self.walls[1][y][x] {

                    maze[y * 2 + 1][x * 2 + 2] = true;

                }

            }

        }

        for x in 0..self.num_edges.width {

            for y in 0..self.num_cells.height {

                self.edge_list[0][y][x] = maze[y][x] != maze[y][x + 1];

            }

        }

        for x in 0..self.num_cells.width {

            for y in 0..self.num_edges.height {

                self.edge_list[1][y][x] = maze[y][x] != maze[y + 1][x];

            }

        }

        let mut fill_points = vec![];

        for x in 0..self.num_edges.width {

            for y in 0..self.num_cells.height {

                if self.edge_list[0][y][x] {

                    self.edge_list[0][y][x] = false;

                    self.add_vertex(Point::new(x as i32 + 1, y as i32 + 1), &mut polygon);

                    self.add_vertex(Point::new(x as i32 + 1, y as i32), &mut polygon);

                    self.add_edge(

                        Point::new(x as i32, y as i32 - 1),

                        Direction::new(0),

                        &mut polygon,

                    );

                    if polygon.len() > 4 {

                        if in_line(polygon.last().unwrap(), &polygon[0], &polygon[1]) {

                            polygon.pop();

                        }

                        for p in &polygon {

                            println!("{} {}", p.x, p.y);

                        }

                        println!("\ne\n");

                        islands.push(Polygon::new(&polygon));

                    }

                    polygon.clear();

                }

            }

        }

        for x in 0..self.num_cells.width {

            for y in 0..self.num_cells.height {

                if maze[y][x] {

                    let half_cell = self.cell_size / 2;

                    let fill_point = Point::new(

                        (x * self.cell_size + half_cell) as i32 + self.off.x,

                        (y * self.cell_size + half_cell) as i32 + self.off.y,

                    );

                    islands.push(Polygon::new(&[fill_point]));

                    fill_points.push(fill_point);

                    let mut points = vec![(x, y)];

                    while let Some((x, y)) = points.pop() {

                        if maze[y][x] {

                            maze[y][x] = false;

                            if x > 0 {

                                points.push((x - 1, y));

                            }

                            if x < self.num_cells.width - 1 {

                                points.push((x + 1, y));

                            }

                            if y > 0 {

                                points.push((x, y - 1));

                            }

                            if y < self.num_cells.height - 1 {

                                points.push((x, y + 1));

                            }

                        }

                    }

                }

            }

        }

        (islands, fill_points)

    }

}

pub struct MazeLandGenerator {

    maze_template: MazeTemplate,

}

fn prev_odd(num: usize) -> usize {

    if num & 1 == 0 {

        num - 1

    } else {

        num

    }

}

impl MazeLandGenerator {

    pub fn new(maze_template: MazeTemplate) -> Self {

        Self { maze_template }

    }

    fn generate_outline(

        &self,

        size: &Size,

        play_box: Rect,

        intersections_box: Rect,

        random_numbers: &mut impl Rng,

    ) -> OutlinePoints {

        let num_steps = if self.maze_template.inverted { 3 } else { 1 };

        let mut step_done = vec![false; num_steps];

        let mut done = false;

        let mut maze = Maze::new(

            &size,

            self.maze_template.cell_size,

            num_steps,

            self.maze_template.inverted,

            self.maze_template.braidness,

            random_numbers,

        );

        while !done {

            done = true;

            for current_step in 0..num_steps {

                if !step_done[current_step] {

                    let dir = Direction::new(random_numbers.gen());

                    step_done[current_step] = maze.see_cell(current_step, dir, random_numbers);

                    done = false;

                }

            }

        }

        let (islands, fill_points) = maze.to_islands();

        OutlinePoints {

            islands,

            walls: vec![],

            fill_points,

            size: *size,

            play_box,

            intersections_box,

        }

    }

}

impl LandGenerator for MazeLandGenerator {

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

        &self,

        parameters: &LandGenerationParameters<T>,

        random_numbers: &mut impl Rng,

    ) -> Land2D<T> {

        let do_invert = self.maze_template.inverted;

        let (basic, zero) = if do_invert {

            (parameters.zero, parameters.basic)

        } else {

            (parameters.basic, parameters.zero)

        };

        let land_size = Size::new(self.maze_template.width, self.maze_template.height);

        let mut land = Land2D::new(&land_size, basic);

        let mut points = self.generate_outline(

            &land.size().size(),

            land.play_box(), //??? Rect::at_origin(land_size).with_margin(land_size.to_square().width as i32 * -2),

            land.play_box(),

            random_numbers,

        );

        if !parameters.skip_distort {

            points.distort(

                parameters.distance_divisor,

                self.maze_template.distortion_limiting_factor,

                random_numbers,

            );

        }

        if !parameters.skip_bezier {

            points.bezierize(5);

        }

        points.draw(&mut land, zero);

        for p in &points.fill_points {

            land.fill(*p, zero, zero)

        }

        land

    }

}