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

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

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

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

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

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

#[derive(Debug, Eq, PartialEq, Hash)]
struct Position {
    x: u8,
    y: u8,
}

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

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

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

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

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

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

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

#[derive(Debug, Eq, PartialEq)]
struct Variable {
    id: String,
    initial_value: i64,
}

#[derive(Debug, PartialEq)]
struct Game {
    name: String,
    version: f64,
    room_format: u8,
    palettes: Vec<Palette>,
    variables: Vec<Variable>,
}

fn test_image_chequers_1() -> Image {
    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,
        ]
    }
}

fn test_image_chequers_2() -> Image {
    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,
        ]
    }
}

fn test_sprite() -> Sprite {
    Sprite {
        id: "a".to_string(),
        name: Some("hatch".to_string()),
        animation_frames: vec![
            Image {
                pixels: vec![
                    0,0,0,0,0,0,0,0,
                    0,1,1,1,1,0,0,0,
                    0,1,0,0,1,0,0,0,
                    0,0,1,1,1,1,0,0,
                    0,0,1,1,1,1,0,0,
                    0,1,0,1,1,1,1,0,
                    0,1,0,1,1,1,1,0,
                    0,1,1,0,1,1,1,1,
                ]
            }
        ],
        dialogue: Some("SPR_0".to_string()),
        room: "4".to_string(),
        position: Position {
            x: 9,
            y: 7
        }
    }
}

fn test_item() -> Item {
    Item {
        id: "6".to_string(),
        animation_frames: vec![
            Image {
                pixels: vec![
                    0,1,0,0,0,0,0,0,
                    0,0,0,0,0,0,0,0,
                    0,0,0,0,0,0,0,0,
                    0,0,0,0,0,1,0,0,
                    0,0,1,0,0,0,0,0,
                    0,0,0,0,0,0,0,0,
                    0,0,0,0,0,0,0,0,
                    0,0,0,0,0,0,1,0,
                ]
            }
        ],
        name: Some("door".to_string()),
        dialogue: Some("ITM_2".to_string())
    }
}

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, false)
}

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_str(&format!("{}", *pixel));
        }
        string.push('\n');
    }

    string.pop(); // remove trailing newline

    string
}

#[test]
fn test_image_to_string() {
    let output = image_to_string(test_image_chequers_1());
    let expected = "10101010\n01010101\n10101010\n01010101\n10101010\n01010101\n10101010\n01010101".to_string();

    assert_eq!(output, expected);
}

fn animation_frames_to_string(animation_frames: Vec<Image>) -> String {
    let mut string = String::new();
    let last_frame = animation_frames.len() - 1;

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

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

    string
}

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 {
    format!(
        "TIL {}\n{}{}{}",
        tile.id,
        animation_frames_to_string(tile.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![
            test_image_chequers_1(),
            test_image_chequers_2(),
        ]
    });

    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);
}

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 position_from_string(string: String) -> Position {
    // e.g. "2,5"
    let xy: Vec<&str> = string.split(',').collect();
    let x = xy[0].parse().unwrap();
    let y = xy[1].parse().unwrap();

    Position {x, y}
}

#[test]
fn test_position_from_string() {
    assert_eq!(
        position_from_string("4,12".to_string()),
        Position { x: 4, y: 12 }
    )
}

fn position_to_string(position: Position) -> String {
    format!("{},{}", position.x, position.y)
}

#[test]
fn test_position_to_string() {
    assert_eq!(
        position_to_string(Position { x: 4, y: 12 }),
        "4,12".to_string()
    )
}

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

    let id = lines[0].replace("SPR ", "");
    let mut name = None;
    let mut dialogue = None;
    let mut room: Option<String> = None;
    let mut position: Option<Position> = None;

    for _ in 0..3 {
        let last_line = lines.pop().unwrap();

        if last_line.starts_with("NAME") {
            name = Some(last_line.replace("NAME ", "").to_string());
        } else if last_line.starts_with("DLG") {
            dialogue = Some(last_line.replace("DLG ", "").to_string());
        } else if last_line.starts_with("POS") {
            let last_line = last_line.replace("POS ", "");
            let room_position: Vec<&str> = last_line.split(' ').collect();
            room     = Some(room_position[0].to_string());
            position = Some(position_from_string(room_position[1].to_string()));
        } else {
            lines.push(last_line); break;
        }
    }

    let room = room.unwrap();
    let position = position.unwrap();

    // todo dedupe
    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();

    Sprite { id, name, animation_frames, dialogue, room, position }
}

#[test]
fn test_sprite_from_string() {
    let output = sprite_from_string("SPR a\n00000000\n01111000\n01001000\n00111100\n00111100\n01011110\n01011110\n01101111\nNAME hatch\nDLG SPR_0\nPOS 4 9,7".to_string());
    let expected = test_sprite();
    
    assert_eq!(output, expected);
}

fn sprite_to_string(sprite: Sprite) -> String {
    format!(
        "SPR {}\n{}{}{}\nPOS {}",
        sprite.id,
        animation_frames_to_string(sprite.animation_frames),
        if sprite.name.is_some() {format!("\nNAME {}", sprite.name.unwrap())} else {"".to_string()},
        if sprite.dialogue.is_some() {format!("\nDLG {}", sprite.dialogue.unwrap())} else {"".to_string()},
        position_to_string(sprite.position),
    )
}

#[test]
fn test_sprite_to_string() {
    let output = sprite_to_string(test_sprite());
    let expected = "SPR a\n00000000\n01111000\n01001000\n00111100\n00111100\n01011110\n01011110\n01101111\nNAME hatch\nDLG SPR_0\nPOS 4 9,7".to_string();
    
    assert_eq!(output, expected);
}

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

    let id = lines[0].replace("ITM ", "");
    let mut name = None;
    let mut dialogue = None;

    for _ in 0..2 {
        let last_line = lines.pop().unwrap();

        if last_line.starts_with("NAME") {
            name = Some(last_line.replace("NAME ", "").to_string());
        } else if last_line.starts_with("DLG") {
            dialogue = Some(last_line.replace("DLG ", "").to_string());
        } else {
            lines.push(last_line); break;
        }
    }
    
    // todo dedupe
    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();
    
    Item { id, name, animation_frames, dialogue }
}

#[test]
fn test_item_from_string() {
    let output = item_from_string("ITM 6\n01000000\n00000000\n00000000\n00000100\n00100000\n00000000\n00000000\n00000010\nNAME door\nDLG ITM_2".to_string());
    let expected = test_item();
    
    assert_eq!(output, expected);
}

fn item_to_string(item: Item) -> String {
    format!(
        "ITM {}\n{}{}{}", 
        item.id, 
        animation_frames_to_string(item.animation_frames),
        if item.name.is_some() {format!("\nNAME {}", item.name.unwrap())} else {"".to_string()},
        if item.dialogue.is_some() {format!("\nDLG {}", item.dialogue.unwrap())} else {"".to_string()},
    )
}

#[test]
fn test_item_to_string() {
    let output = item_to_string(test_item());
    let expected = "ITM 6\n01000000\n00000000\n00000000\n00000100\n00100000\n00000000\n00000000\n00000010\nNAME door\nDLG ITM_2".to_string();
    
    assert_eq!(output, expected);
}

fn exit_from_string(string: String) -> Exit {
    // e.g. "4 3,3"
    let room_position: Vec<&str> = string.split(' ').collect();
    let room = room_position[0].to_string();
    let position = position_from_string(room_position[1].to_string());

    Exit { room, position }
}

#[test]
fn test_exit_from_string() {
    assert_eq!(
        exit_from_string("a 12,13".to_string()),
        Exit { room: "a".to_string(), position: Position { x: 12, y: 13}}
    );
}

fn exit_to_string(exit: Exit) -> String {
    format!("{} {}", exit.room, position_to_string(exit.position))
}

#[test]
fn test_exit_to_string() {
    assert_eq!(
        exit_to_string(Exit { room: "8".to_string(), position: Position { x: 5, y: 6 }}),
        "8 5,6".to_string()
    );
}

fn ending_from_string(string: String) -> Ending {
    let string = string.replace("END ", "");
    let id_dialogue: Vec<&str> = string.split('\n').collect();
    let id = id_dialogue[0].to_string();
    let dialogue = id_dialogue[1].to_string();

    Ending { id, dialogue }
}

#[test]
fn test_ending_from_string() {
    assert_eq!(
        ending_from_string("END a\nThis is a long line of dialogue. Blah blah blah".to_string()),
        Ending { id: "a".to_string(), dialogue: "This is a long line of dialogue. Blah blah blah".to_string() }
    );
}

fn ending_to_string(ending: Ending) -> String {
    format!("END {}\n{}", ending.id, ending.dialogue)
}

#[test]
fn test_ending_to_string() {
    assert_eq!(
        ending_to_string(
            Ending {
                id: "7".to_string(),
                dialogue: "This is another long ending. So long, farewell, etc.".to_string()
            }
        ),
        "END 7\nThis is another long ending. So long, farewell, etc.".to_string()
    );
}

fn dialogue_from_string(string: String) -> Dialogue {
    let lines: Vec<&str> = string.split("\n").collect();
    let id = lines[0].replace("DLG ", "").to_string();
    let contents = lines[1..].join("\n");

    Dialogue { id, contents }
}

#[test]
fn test_dialogue_from_string() {
    assert_eq!(
        dialogue_from_string("DLG h\nhello\ngoodbye".to_string()),
        Dialogue { id: "h".to_string(), contents: "hello\ngoodbye".to_string()}
    )
}

fn dialogue_to_string(dialogue: Dialogue) -> String {
    format!("DLG {}\n{}", dialogue.id, dialogue.contents)
}

#[test]
fn test_dialogue_to_string() {
    assert_eq!(
        dialogue_to_string(
            Dialogue {
                id: "y".to_string(),
                contents: "This is a bit of dialogue,\nblah blah\nblah blah".to_string()
            }
        ),
        "DLG y\nThis is a bit of dialogue,\nblah blah\nblah blah".to_string()
    );
}

fn room_from_string(string: String) -> Room {
    // todo handle room_format?
    let mut lines: Vec<&str> = string.split("\n").collect();
    let id = lines[0].replace("ROOM ", "");
    let mut name = None;
    let mut palette = "0".to_string();
    let mut items: HashMap<Position, String> = HashMap::new();
    let mut exits: HashMap<Position, Exit> = HashMap::new();
    let endings: HashMap<Position, Ending> = HashMap::new();

    loop {
        let last_line = lines.pop().unwrap();

        if last_line.starts_with("NAME") {
            name = Some(last_line.replace("NAME ", "").to_string());
        } else if last_line.starts_with("PAL") {
            palette = last_line.replace("PAL ", "").to_string();
        } else if last_line.starts_with("ITM") {
            let last_line = last_line.replace("ITM ", "");
            let item_position: Vec<&str> = last_line.split(' ').collect();
            let item_id = item_position[0];
            let position = item_position[1];
            let position = position_from_string(position.to_string());

            items.insert(position, item_id.to_string());
        } else if last_line.starts_with("EXT") {
            let last_line = last_line.replace("EXT ", "");
            let parts: Vec<&str> = last_line.split(' ').collect();
            let position = position_from_string(parts[0].to_string());
            let exit = exit_from_string(format!("{} {}", parts[1], parts[2]));

            exits.insert(position, exit);
        } else if last_line.starts_with("END") {

        } else {
            lines.push(last_line); break;
        }
    }

    Room {
        id,
        palette,
        name,
        tiles: vec![],
        items,
        exits,
        endings: Default::default()
    }
}

// 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
//
//     // no - let's try going from the beginning and popping off elements from the start?
// }

// fn game_to_string(game: Game) -> String {
//
// }

fn main() {
    println!("why does a crate need a main function?")
}