use bitsy_parser::game::Game;
use bitsy_parser::image::Image;
use bitsy_parser::tile::Tile;
use image::{GenericImageView, Pixel};
use wasm_bindgen::prelude::*;

const SD: u32 = 8;

#[wasm_bindgen]
pub fn load_default_game_data() {
    let window = web_sys::window().expect("no global `window` exists");
    let document = window.document().expect("should have a document on window");
    let game_data_input = document.get_element_by_id("game-data").expect("no game data input");
    game_data_input.set_inner_html(&bitsy_parser::mock::game_default().to_string());
}

fn tile_name(prefix: &str, index: &u32) -> Option<String> {
    if prefix.len() > 0 {
        Some(format!("{} {}", prefix, index))
    } else {
        None
    }
}

/// image is a base64-encoded string
/// prefix will be ignored if empty
#[wasm_bindgen]
pub fn add_tiles(game_data: String, image: String, prefix: String) -> String {
    let mut game = Game::from(game_data)
        .expect("Couldn't parse game data");

    let image: Vec<&str> = image.split("base64,").collect();
    let image = image[1];
    let image = base64::decode(image).unwrap();
    let image = image::load_from_memory(image.as_ref())
        .expect("Couldn't load image");

    let width  = image.width();
    let height = image.height();
    assert_eq!(width  % 8, 0);
    assert_eq!(height % 8, 0);
    let columns = (width  as f64 / 8.).floor() as u32;
    let rows    = (height as f64 / 8.).floor() as u32;

    let mut tile_index = 1;

    for column in 0..columns {
        for row in 0..rows {
            let mut pixels = Vec::with_capacity(64);

            for y in (row * SD)..((row + 1) * SD) {
                for x in (column * SD)..((column + 1) * SD) {
                    let pixel = image.get_pixel(x, y).to_rgb();
                    let total = pixel[0] as u32 + pixel[1] as u32 + pixel[2] as u32;
                    // is each channel brighter than 128/255 on average?
                    pixels.push(if total >= 384 {1} else {0});
                }
            }

            game.add_tile(Tile {
                /// "0" will get overwritten to a new, safe tile ID
                id: "0".to_string(),
                name: tile_name(&prefix, &tile_index),
                wall: None,
                animation_frames: vec![Image { pixels }],
                colour_id: None
            });

            tile_index += 1;
        }
    }

    game.dedupe_tiles();
    game.to_string()
}

#[cfg(test)]
mod test {
    use crate::add_tiles;

    #[test]
    fn example() {
        let game_data = bitsy_parser::mock::game_default().to_string();
        let image = include_str!("test-resources/test.png.base64").to_string();
        let output = add_tiles(game_data, image, "".to_string());
        let expected = include_str!("test-resources/expected.bitsy");
        assert_eq!(output, expected);
    }
}