use super::circular_index;
use crate::game_of_life::opts::Opts;
use crate::game_of_life::simulation::plane::Plane;
use std::ops::Index;

/// Game of Life universe struct for running simulations
#[derive(Debug, Clone, PartialEq)]
pub(crate) struct Universe {
    pub opts: Opts,
    pub current: Plane<Plane<bool>>,
    pub future: Plane<Plane<bool>>,
}

impl Index<isize> for Universe {
    type Output = Plane<bool>;
    fn index(&self, idx: isize) -> &Plane<bool> {
        let len = self.current.0.len() as isize;
        &self.current[circular_index(idx, len) as isize]
    }
}

#[cfg(test)]
mod index {
    use super::*;

    #[test]
    fn get_element() {
        let opts = Opts {
            seed: 1337,
            input: None,
            width: 13,
            height: 13,
            live_cell: 'L',
            dead_cell: 'D',
            delay: 13,
        };
        let u = Universe {
            opts,
            current: Plane(vec![
                Plane(vec![false; 5]),
                Plane(vec![false, false, true, false, false]),
                Plane(vec![false; 5]),
            ]),
            future: Plane(vec![Plane(vec![])]),
        };

        assert_eq!(u[-3][0], false);
        assert_eq!(u[-3][1], false);
        assert_eq!(u[-3][3], false);
        assert_eq!(u[-3][4], false);
        assert_eq!(u[0][0], false);
        assert_eq!(u[0][1], false);
        assert_eq!(u[0][3], false);
        assert_eq!(u[0][4], false);
        assert_eq!(u[2][0], false);
        assert_eq!(u[2][1], false);
        assert_eq!(u[2][3], false);
        assert_eq!(u[2][4], false);
        assert_eq!(u[5][0], false);
        assert_eq!(u[5][1], false);
        assert_eq!(u[5][3], false);
        assert_eq!(u[5][4], false);

        assert_eq!(u[-2][-3], true);
        assert_eq!(u[-2][2], true);
        assert_eq!(u[-2][7], true);
        assert_eq!(u[1][-3], true);
        assert_eq!(u[1][2], true);
        assert_eq!(u[1][7], true);
        assert_eq!(u[4][-3], true);
        assert_eq!(u[4][2], true);
        assert_eq!(u[4][7], true);
    }
}

impl Universe {
    /// Return the neighboring cells to the cell in index (Y,X) on a plane
    ///
    /// given a cell "C" in a universe of cells "." the immediate neighbors would be "x" as in
    /// the following different examples
    ///
    ///     .....  |  .xxx.  |  .xCx.  |  xCx..  |  Cx..x  |  xx..x  |
    ///     .xxx.  |  .xCx.  |  .xxx.  |  xxx..  |  xx..x  |  Cx..x  |
    ///     .xCx.  |  .xxx.  |  .....  |  .....  |  .....  |  xx..x  |
    ///     .xxx.  |  .....  |  .....  |  .....  |  .....  |  .....  |
    ///     .....  |  .....  |  .xxx.  |  xxx..  |  xx..x  |  .....  |
    ///
    fn neighbors(&self, y: isize, x: isize) -> Vec<bool> {
        vec![
            self[y - 1][x - 1],
            self[y - 1][x],
            self[y - 1][x + 1],
            self[y][x - 1],
            self[y][x + 1],
            self[y + 1][x - 1],
            self[y + 1][x],
            self[y + 1][x + 1],
        ]
    }

    /// Update the current state of the universe (according to the game of life laws) and
    /// set the current state to the next future generation
    pub(crate) fn evolve(mut self) -> Self {
        for row in 0..self.current.len() {
            for col in 0..self.current.0.len() as isize {
                let living_neighbors = self
                    .neighbors(row, col)
                    .iter()
                    .filter(|&c| *c == true)
                    .count();
                match self[row][col] {
                    true if living_neighbors == 2 || living_neighbors == 3 => {
                        self.future[row][col] = true
                    }
                    false if living_neighbors == 3 => self.future[row][col] = true,
                    _ => self.future[row][col] = false,
                }
            }
        }
        self.current = self.future.clone();
        self
    }
}

#[cfg(test)]
mod neighbors {
    use super::*;

    fn opts() -> Opts {
        Opts {
            seed: 1337,
            input: None,
            width: 13,
            height: 13,
            live_cell: 'L',
            dead_cell: 'D',
            delay: 13,
        }
    }

    #[test]
    fn center() {
        let u = Universe {
            opts: opts(),
            future: Plane(vec![Plane(vec![])]),
            current: Plane(vec![
                Plane(vec![false, false, false, false, false]),
                Plane(vec![false, true, true, true, false]),
                Plane(vec![false, true, true, true, false]),
                Plane(vec![false, true, true, true, false]),
                Plane(vec![false, false, false, false, false]),
            ]),
        };
        assert_eq!(u.neighbors(2, 2), vec![true; 8]);
    }

    #[test]
    fn top_edge() {
        let u = Universe {
            opts: opts(),
            future: Plane(vec![Plane(vec![])]),
            current: Plane(vec![
                Plane(vec![false, true, true, true, false]),
                Plane(vec![false, true, true, true, false]),
                Plane(vec![false, false, false, false, false]),
                Plane(vec![false, false, false, false, false]),
                Plane(vec![false, true, true, true, false]),
            ]),
        };
        assert_eq!(u.neighbors(0, 2), vec![true; 8]);
    }

    #[test]
    fn bottom_edge() {
        let u = Universe {
            opts: opts(),
            future: Plane(vec![Plane(vec![])]),
            current: Plane(vec![
                Plane(vec![false, true, true, true, false]),
                Plane(vec![false, false, false, false, false]),
                Plane(vec![false, false, false, false, false]),
                Plane(vec![false, true, true, true, false]),
                Plane(vec![false, true, true, true, false]),
            ]),
        };
        assert_eq!(u.neighbors(4, 2), vec![true; 8]);
    }

    #[test]
    fn left_edge() {
        let u = Universe {
            opts: opts(),
            future: Plane(vec![Plane(vec![])]),
            current: Plane(vec![
                Plane(vec![false, false, false, false, false]),
                Plane(vec![true, true, false, false, true]),
                Plane(vec![true, true, false, false, true]),
                Plane(vec![true, true, false, false, true]),
                Plane(vec![false, false, false, false, false]),
            ]),
        };
        assert_eq!(u.neighbors(2, 0), vec![true; 8]);
    }

    #[test]
    fn right_edge() {
        let u = Universe {
            opts: opts(),
            future: Plane(vec![Plane(vec![])]),
            current: Plane(vec![
                Plane(vec![false, false, false, false, false]),
                Plane(vec![true, false, false, true, true]),
                Plane(vec![true, false, false, true, true]),
                Plane(vec![true, false, false, true, true]),
                Plane(vec![false, false, false, false, false]),
            ]),
        };
        assert_eq!(u.neighbors(2, 4), vec![true; 8]);
    }

    #[test]
    fn bottom_corner_edge() {
        let u = Universe {
            opts: opts(),
            future: Plane(vec![Plane(vec![])]),
            current: Plane(vec![
                Plane(vec![true, false, false, true, true]),
                Plane(vec![false, false, false, false, false]),
                Plane(vec![false, false, false, false, false]),
                Plane(vec![true, false, false, true, true]),
                Plane(vec![true, false, false, true, true]),
            ]),
        };
        assert_eq!(u.neighbors(4, 4), vec![true; 8]);
    }

    #[test]
    fn top_corner_edge() {
        let u = Universe {
            opts: opts(),
            future: Plane(vec![Plane(vec![])]),
            current: Plane(vec![
                Plane(vec![true, true, false, false, true]),
                Plane(vec![true, true, false, false, true]),
                Plane(vec![false, false, false, false, false]),
                Plane(vec![false, false, false, false, false]),
                Plane(vec![true, true, false, false, true]),
            ]),
        };
        assert_eq!(u.neighbors(0, 0), vec![true; 8]);
    }
}

#[cfg(test)]
mod evolve {
    use super::*;

    fn opts() -> Opts {
        Opts {
            seed: 1337,
            input: None,
            width: 13,
            height: 13,
            live_cell: 'L',
            dead_cell: 'D',
            delay: 13,
        }
    }

    #[test]
    fn blinker() {
        let universe = Universe {
            opts: opts(),
            future: Plane(vec![Plane(vec![false; 5]); 3]),
            current: Plane(vec![
                Plane(vec![false, false, false, false, false]),
                Plane(vec![false, true, true, true, false]),
                Plane(vec![false, false, false, false, false]),
            ]),
        };
        assert_eq!(
            universe.evolve(),
            Universe {
                opts: opts(),
                future: Plane(vec![
                    Plane(vec![false, false, true, false, false]),
                    Plane(vec![false, false, true, false, false]),
                    Plane(vec![false, false, true, false, false]),
                ]),
                current: Plane(vec![
                    Plane(vec![false, false, true, false, false]),
                    Plane(vec![false, false, true, false, false]),
                    Plane(vec![false, false, true, false, false]),
                ]),
            }
        )
    }

    #[test]
    fn toad() {
        let universe = Universe {
            opts: opts(),
            future: Plane(vec![Plane(vec![false; 6]); 6]),
            current: Plane(vec![
                Plane(vec![false, false, false, false, false, false]),
                Plane(vec![false, false, false, false, false, false]),
                Plane(vec![false, false, true, true, true, false]),
                Plane(vec![false, true, true, true, false, false]),
                Plane(vec![false, false, false, false, false, false]),
                Plane(vec![false, false, false, false, false, false]),
            ]),
        };
        assert_eq!(
            universe.evolve(),
            Universe {
                opts: opts(),
                future: Plane(vec![
                    Plane(vec![false, false, false, false, false, false]),
                    Plane(vec![false, false, false, true, false, false]),
                    Plane(vec![false, true, false, false, true, false]),
                    Plane(vec![false, true, false, false, true, false]),
                    Plane(vec![false, false, true, false, false, false]),
                    Plane(vec![false, false, false, false, false, false]),
                ]),
                current: Plane(vec![
                    Plane(vec![false, false, false, false, false, false]),
                    Plane(vec![false, false, false, true, false, false]),
                    Plane(vec![false, true, false, false, true, false]),
                    Plane(vec![false, true, false, false, true, false]),
                    Plane(vec![false, false, true, false, false, false]),
                    Plane(vec![false, false, false, false, false, false]),
                ]),
            }
        )
    }
}