use bitsy_parser::game::Game;
use bitsy_parser::image::Image;
use bitsy_parser::tile::Tile;
use image::{GenericImageView, Pixel, DynamicImage};
use lazy_static::lazy_static;
use std::sync::Mutex;
use wasm_bindgen::prelude::*;

const SD: u32 = 8;

struct State {
    game:      Option<Game>,
    image:     Option<DynamicImage>,
    room_name: Option<String>,
    palette:   Option<String>,
}

lazy_static! {
    static ref STATE: Mutex<State> = Mutex::new(
        State {
            game:      None,
            image:     None,
            room_name: None,
            palette:   None,
        }
    );
}

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

#[wasm_bindgen]
pub fn load_default_game()  {
    let mut state = STATE.lock().unwrap();
    state.game = Some(bitsy_parser::mock::game_default());
}

#[wasm_bindgen]
pub fn load_game(game_data: String) -> String {
    let result = Game::from(game_data);
    let mut state = STATE.lock().unwrap();

    match result {
        Ok(game) => {
            state.game = Some(game);
            "".to_string()
        },
        _ => {
            state.game = None;
            format!("{}", result.err().unwrap())
        }
    }
}

#[wasm_bindgen]
pub fn load_image(image_base64: String) -> String {
    let mut state = STATE.lock().expect("Couldn't lock application state");

    let image_base64: Vec<&str> = image_base64.split("base64,").collect();
    let image_base64 = image_base64[1];

    match base64::decode(image_base64) {
        Ok(image) => {
            match image::load_from_memory(image.as_ref()) {
                Ok(image) => {
                    state.image = Some(image);
                    "OK"
                },
                _ => {
                    state.image = None;
                    "Couldn't load image"
                }
            }
        },
        _ => {
            state.image = None;
            "Couldn't decode image"
        }
    }.to_string()
}

#[wasm_bindgen]
pub fn set_room_name(room_name: String) {
    let mut state = STATE.lock().unwrap();

    match room_name.is_empty() {
        true  => { state.room_name = None },
        false => { state.room_name = Some(room_name) },
    }
}

#[wasm_bindgen]
pub fn add_room() -> String {
    let mut state = STATE.lock().expect("Couldn't lock application state");

    if state.game.is_none() {
        return "No game data loaded".to_string();
    }

    let mut game = state.game.clone().unwrap();

    if state.image.is_none() {
        return "No image loaded".to_string();
    }

    let width   = state.image.as_ref().unwrap().width();
    let height  = state.image.as_ref().unwrap().height();
    let columns = (width  as f64 / SD as f64).floor() as u32;
    let rows    = (height as f64 / SD as f64).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 = state.image.as_ref().unwrap().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});
                }
            }

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

            if !game.tiles.contains(&tile) {
                game.add_tile(tile.clone());

                tile_index += 1;
            }
        }
    }

    game.dedupe_tiles();

    state.game = Some(game.to_owned());

    "OK".to_string()
}

#[wasm_bindgen]
pub fn output() -> String {
    let state = STATE.lock().unwrap();

    match &state.game {
        Some(game) => game.to_string(),
        None => "No game loaded".to_string(),
    }
}

#[cfg(test)]
mod test {
    use crate::{add_tiles, load_image, load_default_game, output};

    #[test]
    fn example() {
        load_default_game();
        load_image(include_str!("test-resources/test.png.base64").to_string());
        add_tiles();

        assert_eq!(output(), include_str!("test-resources/expected.bitsy"));
    }
}