use crate::BRIGHTNESS;
use crate::G;
use crate::HEIGHT;
use crate::K1;
use crate::K2;
use crate::Q;
use crate::WIDTH;

#[derive(PartialEq)]
pub struct Cell {
    pub x: u32,
    pub y: u32,
    pub state: u32,
}

#[derive(PartialEq)]
enum StateOp {
    Types,
    States,
}

impl Cell {
    fn neighbor_count(&self, grid: &Vec<Vec<Cell>>, operation: StateOp) -> (u32, u32) {
        let mut infected: u32 = 0;
        let mut states: u32 = 0;
        let mut sum: u32 = 0;
        let mut ill: u32 = 0;

        for j in -1..=1 {
            for i in -1..=1 {
                if i == 0 && j == 0 && operation == StateOp::Types {
                    continue;
                }
                let nx = (self.x as i32 + i + WIDTH as i32) % WIDTH as i32;
                let ny = (self.y as i32 + j + HEIGHT as i32) % HEIGHT as i32;
                let next = &grid[ny as usize][nx as usize];
                let state = next.state;

                if operation == StateOp::Types {
                    if state > 1 && state < Q - 1 {
                        infected += 1;
                    } else if state == Q - 1 {
                        ill += 1;
                    }
                } else {
                    sum += state;
                    if state == 1 && next != self {
                        states += 1;
                    }
                }
            }
        }

        if operation == StateOp::Types {
            return (infected, ill);
        } else {
            return (sum, states);
        }
    }
}

pub fn init_grid(option: Option<&Vec<Vec<Cell>>>) -> Vec<Vec<Cell>> {
    let mut grid: Vec<Vec<Cell>> = Vec::new();
    for j in 0..HEIGHT {
        let mut row: Vec<Cell> = Vec::new();
        for i in 0..WIDTH {
            let mut value = rand::random::<u32>() % Q;
            if let Some(g) = option {
                value = g[j as usize][i as usize].state;
            }

            row.push(Cell {
                x: i,
                y: j,
                state: value,
            });
        }
        grid.push(row);
    }
    grid
}

fn map_num(n: usize, s: usize, e: usize, a: usize, b: usize) -> usize {
    (a as f64 + (n as f64 - s as f64) * (b as f64 - a as f64) / (e as f64 - s as f64)) as usize
}

pub fn display_grid(grid: &Vec<Vec<Cell>>) {
    for j in 0..HEIGHT {
        for i in 0..WIDTH {
            let x = i as usize;
            let y = j as usize;
            let state = grid[y][x].state as usize;

            let index = map_num(state, 0, Q as usize, 0, BRIGHTNESS.len());
            print!("{}", BRIGHTNESS.chars().nth(index).unwrap());
        }
        println!();
    }
}

pub fn update_grid(grid: &mut Vec<Vec<Cell>>) {
    let mut new_gen = init_grid(Some(grid));
    for j in 0..HEIGHT {
        for i in 0..WIDTH {
            let x = i as usize;
            let y = j as usize;

            let current = &grid[y][x];
            let next = &mut new_gen[y][x];

            if current.state == Q - 1 {
                next.state = 0;
            } else if current.state == 0 {
                let (inf, ill) = current.neighbor_count(&grid, StateOp::Types);
                next.state = inf / K1 + ill / K2;
            } else {
                let (sum, states) = current.neighbor_count(&grid, StateOp::States);
                next.state = sum / (9 - states) + G;
            }

            if next.state >= Q {
                next.state = Q - 1;
            }
        }
    }
    *grid = new_gen;
}