use std::fmt;
use std::collections::HashMap;

const IMAGE_DIMENSION_SD: usize = 8;
const IMAGE_DIMENSION_HD: usize = 16;

#[derive(Eq, PartialEq)]
struct Colour {
    red:   u8,
    green: u8,
    blue:  u8,
}

#[derive(Eq, PartialEq)]
struct Palette {
    id: String, // base36 string (why??)
    name: Option<String>,
    colours: Vec<Colour>,
}

#[derive(Eq, PartialEq)]
struct Image {
    pixels: Vec<u8>, // 64 for SD, 256 for HD
}

#[derive(Eq, PartialEq)]
struct Tile {
    id: String, // base36 string
    name: Option<String>,
    wall: bool,
    animation_frames: Vec<Image>,
}

#[derive(Eq, PartialEq, Hash)]
struct Position {
    room: String, // id. is room id int or base36 string?
    x: u8,
    y: u8,
}

#[derive(Eq, PartialEq)]
struct Dialogue {
    id: String,
    contents: String,
}

#[derive(Eq, PartialEq)]
struct Sprite {
    id: String, // lowercase base36
    name: Option<String>,
    animation_frames: Vec<Image>,
    dialogue: Option<Dialogue>,
    position: Position,
}

/// avatar is a "sprite" in the game data but with a specific ID
#[derive(Eq, PartialEq)]
struct Avatar {
    animation_frames: Vec<Image>,
    position: Position,
}

#[derive(Eq, PartialEq)]
struct Item {
    id: String,
    animation_frames: Vec<Image>,
    name: Option<String>,
    dialogue: Option<Dialogue>,
}

#[derive(Eq, PartialEq)]
struct Exit {
    /// destination
    room: String,  /// id
    position: Position,
}

// same as a dialogue basically
#[derive(Eq, PartialEq)]
struct Ending {
    contents: String,
}

#[derive(Eq, PartialEq)]
struct Room {
    id: String,
    palette: String, /// id
    name: Option<String>,
    items: HashMap<Position, Item>,
    exits: HashMap<Position, Exit>,
    endings: HashMap<Position, Ending>,
}

#[derive(PartialEq)]
struct Game {
    name: String,
    version: f64,
    room_format: bool,
    palettes: Vec<Palette>,
}

impl fmt::Debug for Colour {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Colour")
            .field("red", &self.red)
            .field("green", &self.green)
            .field("blue", &self.blue)
            .finish()
    }
}

impl fmt::Debug for Palette {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Palette")
            .field("id", &self.id)
            .field("name", &self.name)
            .field("colours", &self.colours)
            .finish()
    }
}

impl fmt::Debug for Image {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Image")
            .field("pixels", &self.pixels)
            .finish()
    }
}

impl fmt::Debug for Tile {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Tile")
            .field("id", &self.id)
            .field("name", &self.name)
            .field("wall", &self.wall)
            .field("animation_frames", &self.animation_frames)
            .finish()
    }
}

fn image_from_string(string: String) -> Image {
    let string = string.replace("\n", "");
    let pixels: Vec<&str> = string.split("").collect();
    // the above seems to add an extra "" at the start and end of the vec, so strip them below
    let pixels = &pixels[1..(pixels.len() - 1)];
    let pixels: Vec<u8> = pixels.iter().map(|&pixel| { pixel.parse::<u8>().unwrap() }).collect();

    Image { pixels }
}

#[test]
fn test_image_from_string() {
    let output = image_from_string(
        "11111111\n11001111\n10111111\n11111111\n11111111\n11111111\n11111111\n11111111".to_string()
    );

    let expected = Image {
        pixels: vec![
            1,1,1,1,1,1,1,1,
            1,1,0,0,1,1,1,1,
            1,0,1,1,1,1,1,1,
            1,1,1,1,1,1,1,1,
            1,1,1,1,1,1,1,1,
            1,1,1,1,1,1,1,1,
            1,1,1,1,1,1,1,1,
            1,1,1,1,1,1,1,1,
        ]
    };

    assert_eq!(output, expected)
}

fn image_to_string(image: Image) -> String {
    image_to_string_opts(image, true)
}

fn image_to_string_opts(image: Image, hd: bool) -> String {
    let mut string = String::new();
    let chunk_size = if hd {IMAGE_DIMENSION_HD} else {IMAGE_DIMENSION_SD};

    for line in image.pixels.chunks(chunk_size) {
        for pixel in line {
            string.push(*pixel as char);
        }
        string.push('\n');
    }

    string.pop(); // remove trailing newline

    string
}

#[test]
fn test_image_to_string() {
    let output = image_to_string(Image {
        pixels: vec![
            1,0,1,0,1,0,1,0,
            0,1,0,1,0,1,0,1,
            1,0,1,0,1,0,1,0,
            0,1,0,1,0,1,0,1,
            1,0,1,0,1,0,1,0,
            0,1,0,1,0,1,0,1,
            1,0,1,0,1,0,1,0,
            0,1,0,1,0,1,0,1,
        ]
    });

    let expected = "10101010\n01010101\n10101010\n01010101\n10101010\n01010101\n10101010\n01010101".to_string();

    assert_eq!(output, expected);
}

fn tile_from_string(string: String) -> Tile {
    let mut lines: Vec<&str> = string.split("\n").collect();

    let id = lines[0].replace("TIL ", "");

    let last_line = lines.pop().unwrap();
    let wall = match last_line == "WAL true" {
        true => true,
        false => {
            lines.push(last_line);
            false
        }
    };

    let last_line = lines.pop().unwrap();
    let name = match last_line.starts_with("NAME") {
        true => Some(last_line.replace("NAME ", "").to_string()),
        false => {
            lines.push(last_line);
            None
        }
    };

    let animation_frames = lines[1..].join("");
    let animation_frames: Vec<&str> = animation_frames.split("\n>\n").collect();
    let animation_frames: Vec<Image> = animation_frames.iter().map(|&frame| {
        image_from_string(frame.to_string())
    }).collect();

    Tile {id, name, wall, animation_frames}
}

#[test]
fn test_tile_from_string() {
    let output = tile_from_string("TIL z\n11111111\n11111111\n11111111\n11111111\n11111111\n11111111\n11111111\n11111111\nNAME concrete 1\nWAL true".to_string());
    
    let expected = Tile {
        id: "z".to_string(),
        name: Some("concrete 1".to_string()),
        wall: true,
        animation_frames: vec![
            Image {
                pixels: vec![1; 64]
            }
        ],
    };
    
    assert_eq!(output, expected);
}

fn tile_to_string(tile: Tile) -> String {
    let mut animation_frames = String::new();
    let last_frame = tile.animation_frames.len() - 1;

    for (i, frame) in tile.animation_frames.into_iter().enumerate() {
        animation_frames.push_str(&image_to_string(frame));

        if i < last_frame {
            animation_frames.push_str(&"\n>\n".to_string());
        }
    }

    format!(
        "TIL {}\n{}{}{}",
        tile.id,
        animation_frames,
        if tile.name.is_some() {format!("\nNAME {}", tile.name.unwrap())} else {"".to_string()},
        if tile.wall {"\nWAL true"} else {""}
    )
}

#[test]
fn test_tile_to_string() {
    let output = tile_to_string(Tile {
        id: "7a".to_string(),
        name: Some("chequers".to_string()),
        wall: false,
        animation_frames: vec![
            Image { pixels: vec![
                1,0,1,0,1,0,1,0,
                0,1,0,1,0,1,0,1,
                1,0,1,0,1,0,1,0,
                0,1,0,1,0,1,0,1,
                1,0,1,0,1,0,1,0,
                0,1,0,1,0,1,0,1,
                1,0,1,0,1,0,1,0,
                0,1,0,1,0,1,0,1,
            ]},
            Image { pixels: vec![
                0,1,0,1,0,1,0,1,
                1,0,1,0,1,0,1,0,
                0,1,0,1,0,1,0,1,
                1,0,1,0,1,0,1,0,
                0,1,0,1,0,1,0,1,
                1,0,1,0,1,0,1,0,
                0,1,0,1,0,1,0,1,
                1,0,1,0,1,0,1,0,
            ]},
        ]
    });

    let expected = "TIL 7a\n10101010\n01010101\n10101010\n01010101\n10101010\n01010101\n10101010\n01010101\n>\n01010101\n10101010\n01010101\n10101010\n01010101\n10101010\n01010101\n10101010\nNAME chequers".to_string();

    assert_eq!(output, expected);
}

// todo support Bitsy HD?
// todo impl (Game::from_string etc.)

fn colour_from_string(colour: String) -> Colour {
    let values: Vec<&str> = colour.split(',').collect();

    let red:   u8 = values[0].parse().unwrap_or(0);
    let green: u8 = values[1].parse().unwrap_or(0);
    let blue:  u8 = values[2].parse().unwrap_or(0);

    Colour { red, green, blue }
}

#[test]
fn test_colour_from_string() {
    assert_eq!(
        colour_from_string("0,255,0".to_string()),
        Colour { red: 0, green: 255, blue: 0 }
    );
}

fn colour_to_string(colour: Colour) -> String {
    format!("{},{},{}", colour.red, colour.green, colour.blue)
}

#[test]
fn test_colour_to_string() {
    assert_eq!(
        colour_to_string(Colour { red: 22, green: 33, blue: 44 }),
        "22,33,44".to_string()
    );
}

fn palette_from_string(palette: String) -> Palette {
    let lines: Vec<&str> = palette.split('\n').collect();

    let id = lines[0].replace("PAL ", "");

    let name = match lines[1].starts_with("NAME") {
        true  => Some(lines[1].replace("NAME ", "").to_string()),
        false => None,
    };

    let colour_start_index = if name.is_some() {2} else {1};

    let colours = lines[colour_start_index..].iter().map(|&line| {
        colour_from_string(line.to_string())
    }).collect();

    Palette { id, name, colours }
}

#[test]
fn test_palette_from_string() {
    let output = palette_from_string(
        "PAL 1\nNAME lamplight\n45,45,59\n66,60,39\n140,94,1".to_string()
    );

    let expected = Palette {
        id: "1".to_string(),
        name: Some("lamplight".to_string()),
        colours: vec![
            Colour {red: 45,  green: 45, blue: 59},
            Colour {red: 66,  green: 60, blue: 39},
            Colour {red: 140, green: 94, blue: 1 },
        ],
    };

    assert_eq!(output, expected);
}

#[test]
fn test_palette_from_string_no_name() {
    let output = palette_from_string(
        "PAL 9\n45,45,59\n66,60,39\n140,94,1".to_string()
    );

    let expected = Palette {
        id: "9".to_string(),
        name: None,
        colours: vec![
            Colour {red: 45,  green: 45, blue: 59},
            Colour {red: 66,  green: 60, blue: 39},
            Colour {red: 140, green: 94, blue: 1 },
        ],
    };

    assert_eq!(output, expected);
}

// fn get_avatar(game: Game) -> Sprite {
//     // get the sprite with an id of A
// }

// fn game_from_string(game: String ) -> Game {
//     // probably needs to split the game data into different segments starting from the end
//     // e.g. VAR... then END... then DLG...
//     // then split all these up into their individual items
// }
//
// fn game_to_string(game: Game) -> String {
//
// }

fn main() {
    println!("why am I here?")
}