use ggez::event::{self, EventHandler};
use ggez::graphics::{self, Color, DrawMode, Mesh, MeshBuilder};
use ggez::{Context, ContextBuilder, GameResult};

struct Apr {
    row: i32,
    col: i32,
    board: Vec<Vec<u8>>,
    grid: Mesh,
    should_update_grid: bool,
    // Your state here...
    __TEST_state: usize
}

fn make_grid(ctx: &mut Context, r: i32, c: i32, board: &[Vec<u8>]) -> GameResult<Mesh> {
    let start_x: f32 = 20.0;
    let start_y: f32 = 20.0;
    let size: f32 = 4.0; //compile time constants for now

    let mut builder = MeshBuilder::new();

    for row in 0..r {
        for col in 0..c {
            builder.rectangle(
                DrawMode::fill(),
                graphics::Rect {
                    x: start_x + (size * col as f32),
                    y: start_y + (size * row as f32),
                    w: size,
                    h: size,
                },
                match board[row as usize][col as usize]  {
                    0 => Color::WHITE,
                    1 => Color::BLACK,
                    2 => Color::RED,
                    3 => Color::CYAN,
                    4 => Color::YELLOW,
                    5 => Color::GREEN,
                    6 => Color::BLUE,
                    7 => Color::MAGENTA,
                    _ => Color::BLACK,
                }
            )?;
        }
    }

    builder.build(ctx)
}

fn make_board(r: i32, c: i32) -> Vec<Vec<u8>> {
    let mut init : Vec<Vec<u8>> = vec![vec![0u8; r as usize]; c as usize];
    for row in 0..r as usize {
        for col in 0..c as usize {
            init[row][col] = (row + col) as u8 % 8;
        }
    }
    init
}

impl Apr {
    pub fn new(_ctx: &mut Context, r: i32, c: i32) -> Apr {
        // Load/create resources such as images here.
        let board = make_board(r, c);
        Apr {
            row: r,
            col: c,
            grid: make_grid(_ctx, r, c, board.as_slice()).unwrap(),
            board: board,
            should_update_grid: false,
            __TEST_state: 0,
        }
    }

    fn set_colour(&mut self, r : usize, c : usize, col : u8) -> GameResult<()> {
        self.board[r][c] = col;
        self.should_update_grid = true;
        Ok(())
    }
}

impl EventHandler for Apr {
    fn update(&mut self, _ctx: &mut Context) -> GameResult<()> {
        // Err(ggez::GameError::CustomError("You done messed up trying to play this game!".to_string()))
        // Update code here...
        for _x in 0..self.row*self.col {
            let c = self.__TEST_state % self.col as usize;
            let r = (self.__TEST_state / self.row as usize) % self.row as usize;
            self.set_colour(r, c, (self.board[r][c] + 1) % 8)?;
            self.__TEST_state += 1;
        }
        Ok(())
    }

    fn draw(&mut self, ctx: &mut Context) -> GameResult<()> {
        graphics::clear(ctx, Color::new(0.5, 0.5, 0.5, 1.0));
        let drawparams = graphics::DrawParam::new();

        if self.should_update_grid {
            self.grid = make_grid(ctx, self.row, self.col, self.board.as_slice())?;
            self.should_update_grid = false;
        }
        graphics::draw(ctx, &self.grid, drawparams)?;
        // Draw code here...
        graphics::present(ctx)
    }
}

fn main() {
    // Make a Context.
    let (mut ctx, event_loop) = ContextBuilder::new("apruebo", "s1m7u and e-dt")
        .build()
        .expect("aieee, could not create ggez context!");

    // Create an instance of your event handler.
    // Usually, you should provide it with the Context object to
    // use when setting your game up.
    let apr = Apr::new(&mut ctx, 128, 128);

    // Run!
    event::run(ctx, event_loop, apr);
}