use sdl2::render::Canvas;
use sdl2::pixels::Color;
use sdl2::video::Window;
use sdl2::rect::Rect;


use std::cmp;
use std::{thread, time};
use std::time::{Duration, SystemTime};

pub const SCREEN_SIZE: u32 = 800;
pub const PX_SIZE: u32 = 2;
pub const BLACK: Color =  Color::RGB(0, 0, 0);
pub const WHITE: Color =  Color::RGB(255, 255, 255);

pub trait Cell {
    fn color(&self) -> [f32; 4];
}

#[derive(Clone)]
pub struct ConwayCell {
    color: Color,
    alive: bool,
}

/*
impl Cell {
    pub fn clone(&self) -> Cell {
        Cell{color: self.color}
    }
}*/

pub struct App {
    steps_per_sec: u64,
    px_size: i32,
    grid: Vec<Vec<ConwayCell>>,
    canvas: Canvas<Window>,
}

impl App {
    fn render (&mut self) {

        self.canvas.set_draw_color(Color::RGB(0, 0, 0));
        self.canvas.clear();

        for y in 0..self.grid.len() {
            for x in 0..self.grid[y].len() {
                if self.grid[y][x].alive {
                    self.canvas.set_draw_color(self.grid[y][x].color);
                    self.canvas.fill_rect(Rect::new(x as i32 * self.px_size , y as i32 * self.px_size, self.px_size as u32, self.px_size as u32));
                }
            }
        }

        /*
          for (y, row) in grid.iter().enumerate() {
              for (x, cell) in row.iter().enumerate() {
                  rectangle( cell.color, rectangle::square((x as u32 * px_size) as f64, (y as u32 * px_size) as f64, px_size as f64), c.transform, gl)
              }
          }*/


        self.canvas.present();
    }


    fn evolve(&mut self) {
        let mut new_grid = vec![vec![ConwayCell{color: BLACK, alive: false}; self.grid.len()]; self.grid.len()];

        for y in 0..self.grid.len() {
            for x in 0..self.grid[y].len() {
                let mut nalive = 0;

                let mut ylow = 0;
                if y > 1 {
                    ylow = y-1;
                }
                let yhigh = cmp::min(self.grid.len()-1, y+1);

                let mut xlow = 0;
                if x > 1 {
                    xlow = x-1;
                }
                let xhigh =  cmp::min(self.grid.len()-1, x+1);

                for i in ylow..yhigh+1 {
                    for j in xlow..xhigh+1 {
                        if i == y && j == x {
                            continue;
                        }
                        if self.grid[i][j].alive {
                            nalive += 1;
                        }
                    }
                }

                if self.grid[y][x].alive {
                    if nalive == 2 || nalive == 3 {
                        new_grid[y][x] = ConwayCell{color: WHITE, alive: true}
                    }
                } else if nalive == 3 {
                    new_grid[y][x] = ConwayCell{color: WHITE, alive: true}
                }
            }
        }
        self.grid = new_grid;
    }
}

fn main() {
    let sdl_context = sdl2::init().unwrap();
    let video_subsystem = sdl_context.video().unwrap();
    let window = video_subsystem.window("Microworlds", SCREEN_SIZE, SCREEN_SIZE).build().unwrap();



    let size: usize = (SCREEN_SIZE/PX_SIZE) as usize;
    let mut grid = vec![vec![ConwayCell{color: BLACK, alive: false}; size]; size];
    println!("size:{}", size);

    // r pemento
    let centery = size/2;
    let centerx = size/2;
    println!("centery:{} centerx:{}", centery, centerx);
    grid[centery][centerx] = ConwayCell{color: WHITE, alive: true};
    grid[centery+1][centerx] = ConwayCell{color: WHITE, alive: true};
    grid[centery-1][centerx] = ConwayCell{color: WHITE, alive: true};

    grid[centery-1][centerx-1] = ConwayCell{color: WHITE, alive: true};
    grid[centery][centerx+1] = ConwayCell{color: WHITE, alive: true};

    // Let's create a Canvas which we will use to draw in our Window
    let canvas : Canvas<Window> = window.into_canvas()
        .present_vsync() //< this means the screen cannot
        // render faster than your display rate (usually 60Hz or 144Hz)
        .build().unwrap();

    let mut app = App {
        steps_per_sec: 32,
        px_size: PX_SIZE as i32,
        grid: grid,
        canvas: canvas,
    };


    let mut frame = 0;

    let mut event_pump = sdl_context.event_pump().unwrap();
    'main: loop {
        for event in event_pump.poll_iter() {
            match event {
                sdl2::event::Event::Quit {..} => break 'main,
                _ => {},
            }
        }

        let start_rend = SystemTime::now();
        app.render();
        let render_time = start_rend.elapsed().unwrap();
        let start_evo = SystemTime::now();
        app.evolve();
        let evo_time = start_evo.elapsed().unwrap();
        let total_time = start_rend.elapsed().unwrap();
        frame += 1;
        println!("frame: {} - render time: {:?} | evolve time: {:?} | total time: {:?}", frame, render_time, evo_time, total_time);

        thread::sleep(time::Duration::from_millis(1000 / app.steps_per_sec));
    }

}