use std::{fs::File, io::{Read, Write}};
use env_logger::Builder;
use log::{error, info, LevelFilter};
use serde::{Deserialize, Serialize};
use xml::{XAlbumItem, XArgument, XDataSet, XDatabase, XPlaylist, XSomeList, XTrackItem};

mod xml;

enum ChunkType {
    Database,
    DataSet,
    AlbumList,
    AlbumItem,
    TrackList,
    TrackItem,
    StringTypes,
    PlaylistList,
    Playlist,
    Unknown
}

impl From<[u8; 4]> for ChunkType {
    fn from(value: [u8; 4]) -> Self {
        match value {
            [0x6D, 0x68, 0x62, 0x64] => ChunkType::Database,
            [0x6D, 0x68, 0x73, 0x64] => ChunkType::DataSet,
            [0x6D, 0x68, 0x69, 0x61] => ChunkType::AlbumList,
            [0x6D, 0x68, 0x6C, 0x61] => ChunkType::AlbumItem,
            [0x6D, 0x68, 0x6C, 0x74] => ChunkType::TrackList,
            [0x6D, 0x68, 0x69, 0x74] => ChunkType::TrackItem,
            [0x6D, 0x68, 0x6F, 0x64] => ChunkType::StringTypes,
            [0x6D, 0x68, 0x6C, 0x70] => ChunkType::PlaylistList,
            [0x6D, 0x68, 0x79, 0x70] => ChunkType::Playlist,
            _ => ChunkType::Unknown
        }
    }
}

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct ChunkHeader {
    chunk_type: [u8; 4],
    end_of_chunk: u32,
    children_count: u32
}

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct Database {
    unknown: u32,
    version: u32,
    children_count: u32,
    id: u64,
    unknown1: [u8; 32],
    language: u16,
    persistent_id: u64,
    hash: [u8; 20]
}

#[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
struct DataSet {
    data_type: u32
}

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct AlbumItem {
    number_of_strings: u32,
    unknown: u16,
    album_id_for_track: u16,
    timestamp: u64,
    unknown1: u32
}

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct TrackItem {
	number_of_strings: u32, // number of mhod's count
    unique_id: u32,
    visible: u32,
    filetype: u32,
    type1: u8,
    type2: u8,
    compilation_flag: u8,
    stars: u8,
    last_modified_time: u32,
    size: u32,
    length: u32,
    track_number: u32,
    total_tracks: u32,
    year: u32,
    bitrate: u32,
    sample_rate: u32,
    volume: u32,
    start_time: u32,
    stop_time: u32,
    soundcheck: u32,
    play_count: u32,
    play_count2: u32,
    last_played_time: u32,
    disc_number: u32,
    total_discs: u32,
    userid: u32,
    date_added: u32,
    bookmark_time: u32,
    dbid: u64,
    checked: u8,
    application_rating: u8,
    bpm: u16,
    artwork_count: u16,
    unk9: u16,
    artwork_size: u32,
    unk11: u32,
    sample_rate2: u32,
    date_released: u32,
    unk14: u32,
    unk15: u32,
    unk16: u32,
    skip_count: u32,
    last_skipped: u32,
    has_artwork: u8,
    skip_when_shuffling: u8,
    remember_playback_position: u8,
    flag4: u8,
    dbid2: u64,
    lyrics_flag: u8,
    movie_file_flag: u8,
    played_mark: u8,
    unk17: u8,
    unk21: u32,
    pregap: u32,
    sample_count: u64,
    unk25: u32,
    postgap: u32,
    unk27: u32,
    media_type: u32,
    season_number: u32,
    episode_number: u32,
    unk31: [u8; 28],
    gapless_data: u32,
    unk38: u32,
    gapless_track_flag: u16,
    gapless_album_flag: u16,
    unk39_hash: [u8; 20],
    unk40: [u8; 18],
    album_id: u16,
    mhii_link: u32
}

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct StringEntry { // mhod
    entry_type: u32,
    unk1: u32,
    unk2: u32,
    position: u32,
    length: u32,
    unknown: u32,
    unk4: u32
}

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct PlaylistIndexEntry { // mhod
    entry_type: u32,
    unk1: u32,
    unk2: u32,
    index_type: u32,
    count: u32,
    null_padding: u64,
    null_padding1: u64,
    null_padding2: u64,
    null_padding3: u64,
    null_padding4: u64
}

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct LetterJumpEntry {
    entry_type: u32,
    unk1: u32,
    unk2: u32,
    index_type: u32,
    count: u32,
    null_padding: u64
}

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct JumpTable {
    letter: u32, // UTF-16 LE Uppercase with two padding null bytes
    entry_num: u32, // the number of the first entry in the corresponding MHOD52 index starting with this letter. Zero-based and incremented by one for each entry, not 4. 
    count: u32 // the count of entries starting with this letter in the corresponding MHOD52. 
}

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct Playlist {
    data_object_child_count: u32,
    playlist_item_count: u32,
    is_master_playlist_flag: u8,
    unk: [u8; 3],
    timestamp: u32,
    persistent_playlist_id: u64,
    unk3: u32,
    string_mhod_count: u16,
    podcast_flag: u16,
    list_sort_order: u32
}

enum ChunkState {
    Header,
    Data
}

pub fn parse_bytes(data: &[u8]) -> XDatabase {
    let mut xdb = XDatabase{data: None, children: Vec::new()};
    let mut state = ChunkState::Header;
    let mut chunk_header: Option<ChunkHeader> = None;
    let mut last_type: u32 = 0;
    let mut i = 0;
    while i < data.len() {
        state = match state {
            ChunkState::Header => {
                if i + 12 >= data.len() { break; }
                chunk_header = Some(bincode::deserialize(&data[i..i+12]).unwrap());
                i += 12;
                ChunkState::Data
            },
            ChunkState::Data => {
                let mut u = 0;
                let header = chunk_header.unwrap();
                match ChunkType::from(header.chunk_type) {
                    ChunkType::Database => {
                        info!("Db header: {:?}", header);
                        u = usize::try_from(header.end_of_chunk).unwrap() - 12;
                        let db: Database = bincode::deserialize(&data[i..i+u]).unwrap();
                        info!("val: {:?}", db);
                        xdb.data = Some(db);
                    },
                    ChunkType::DataSet => {
                        u = usize::try_from(header.end_of_chunk).unwrap() - 12;
                        let ds: DataSet = bincode::deserialize(&data[i..i+u]).unwrap();
                        info!("val: {:?}", ds);
                        xdb.children.push(XDataSet { data: ds.clone(), child: match ds.data_type {
                            3 => XSomeList::Playlists(Vec::new()), // Playlist List
                            4 => XSomeList::AlbumList(Vec::new()), // Album List
                            _ => XSomeList::TrackList(Vec::new()) // 1 Track List
                        }});
                    },
                    ChunkType::AlbumList => {
                        info!("AlbumList");
                        u = usize::try_from(header.end_of_chunk).unwrap() - 12;
                        last_type = 4;
                    },
                    ChunkType::AlbumItem => {
                        u = usize::try_from(header.end_of_chunk).unwrap() - 12;
                        let ai: AlbumItem = bincode::deserialize(&data[i..i+u]).unwrap();
                        info!("val: {:?}", ai);
                        if let XSomeList::AlbumList(albums) = &mut xdb.find_dataset(4).child {
                            albums.push(XAlbumItem {data: ai,args: Vec::new()});
                        }
                    },
                    ChunkType::TrackList => {
                        info!("TrackList");
                        u = usize::try_from(header.end_of_chunk).unwrap() - 12;
                        last_type = 1;
                    },
                    ChunkType::TrackItem => {
                        u = usize::try_from(header.end_of_chunk).unwrap() - 12;
                        let ti: TrackItem = bincode::deserialize(&data[i..i+u]).unwrap();
                        info!("val: {:?}", ti);
                        if let XSomeList::TrackList(tracks) = &mut xdb.find_dataset(1).child {
                            tracks.push(XTrackItem {data: ti,args: Vec::new()});
                        }
                    },
                    ChunkType::StringTypes => {
                        u = usize::try_from(header.children_count).unwrap() - 12;
                        let header_offset: usize = (header.end_of_chunk + 4) as usize;
                        let entry_type = u32::from_le_bytes(data[i..i+4].try_into().unwrap());
                        match entry_type {
                            0..=15 => {
                                let str_end: usize = (header.children_count - 12) as usize;
                                let entry: StringEntry = bincode::deserialize(&data[i..i+28]).unwrap();
                                info!("val: {:?}", &entry);
                                let mut bytes = Vec::new();
    
                                let mut h = i+header_offset;
                                while h < i+str_end {
                                    if data[h] != 0 {
                                        bytes.push(data[h]);
                                    }
                                    h+=1;
                                }
                                let g = String::from_utf8(bytes).unwrap();
                                info!("str: {}", g);
                                match &mut xdb.find_dataset(last_type).child {
                                    XSomeList::AlbumList(albums) => {
                                        albums.last_mut().unwrap().args.push(XArgument{ arg_type: entry_type, val: g});
                                    },
                                    XSomeList::Playlists(playlists) => {
                                        playlists.last_mut().unwrap().args.push(XArgument{ arg_type: entry_type, val: g});
                                    },
                                    XSomeList::TrackList(tracks) => {
                                        tracks.last_mut().unwrap().args.push(XArgument{ arg_type: entry_type, val: g});
                                    }
                                }
                            },
                            52 => {
                                let entry: PlaylistIndexEntry = bincode::deserialize(&data[i..i+60]).unwrap();
                                info!("valPl: {:?}", &entry);
                                let mut h = i+60;
                                let mut v = Vec::new();
                                while h < i+60+((4*entry.count) as usize) {
                                    v.push(u32::from_le_bytes(data[h..h+4].try_into().unwrap()));
                                    h += 4;
                                }
                                info!("Indexes: {:?}", v);
                            },
                            53 => {
                                let entry: LetterJumpEntry = bincode::deserialize(&data[i..i+28]).unwrap();
                                info!("valJT: {:?}", &entry);
                                let mut h = i+28;
                                let mut v: Vec<JumpTable> = Vec::new();
                                while h < i+28+((12*entry.count) as usize) {
                                    v.push(bincode::deserialize(&data[h..h+12]).unwrap());
                                    h += 12;
                                }
                                info!("Indexes: {:?}", v);
                            },
                            100 => {

                            },
                            102 => {

                            },
                            _ => {}
                        }
                    },
                    ChunkType::PlaylistList => {
                        info!("Playlists count: {}", header.children_count);
                        u = usize::try_from(header.end_of_chunk).unwrap() - 12;
                        last_type = 3;
                    },
                    ChunkType::Playlist => {
                        u = usize::try_from(header.end_of_chunk).unwrap() - 12;
                        let playlist: Playlist = bincode::deserialize(&data[i..i+u]).unwrap();
                        info!("playlist: {:?}", playlist);
                        if let XSomeList::Playlists(playlists) = &mut xdb.find_dataset(3).child {
                            playlists.push(XPlaylist {data: playlist,args: Vec::new()});
                        }
                    },
                    _ => { u = 1; }
                }
                i += u;
                chunk_header = None;
                ChunkState::Header
            }
        }
    }
    //let mut f = File::create("output.json").unwrap();
    //let r = f.write(serde_json::to_string::<XDatabase>(&xdb).unwrap().as_bytes());
    //info!("Result: {:?}", r);
    xdb
}

/*fn main() {

    // Initialize the logger with 'info' as the default level
    Builder::new()
        .filter(None, LevelFilter::Info)
        .init();

    let mut f = File::open("D:\\Documents\\iTunes\\iTunesDB").unwrap();
    let mut buf = Vec::new();
    match f.read_to_end(&mut buf) {
        Ok(n) => {
            let data = &buf[..n];
            parse_bytes(data);
        },
        Err(e) => {
            error!("Error: {}",e);
        }
    }
}*/