use crate::driver::FileDriver;
use crate::utils::{IoCursor, ReadUtils};
use crate::zip::{CompressionMethod, ZipError, ZipFileInfo, ZipResult};
use bzip2::read::BzDecoder;
use flate2::read::DeflateDecoder;
use liblzma::read::XzDecoder;
use liblzma::stream::{Filters, LzmaOptions, Stream};
use std::io::{
    BufReader, Error as IoError, ErrorKind as IoErrorKind, Read, Result as IoResult, Seek, SeekFrom,
};
use zstd::stream::Decoder as ZstdDecoder;

enum Compression<Io: Read> {
    Store(Io),
    Deflate(DeflateDecoder<Io>),
    BZip2(BzDecoder<Io>),
    Zstd(ZstdDecoder<'static, BufReader<Io>>),
    Xz(XzDecoder<Io>),
}

pub struct ZipFileReader<'d, Io: Read> {
    io: Compression<IoCursor<&'d mut Io>>,
    info: &'d ZipFileInfo,
}

impl<'d, Io: Read> FileDriver for ZipFileReader<'d, Io> {
    type Io = Io;
    type FileInfo = ZipFileInfo;

    fn info(&self) -> &Self::FileInfo {
        self.info
    }
}

impl<'d, Io: Read + Seek> ZipFileReader<'d, Io> {
    pub fn new(io: &'d mut Io, info: &'d ZipFileInfo) -> ZipResult<Self> {
        io.seek(SeekFrom::Start(info.header_pointer))?;

        let buf = io.read_arr::<30>()?;
        if u32::from_le_bytes(buf[..4].try_into().unwrap()) != 0x04034b50 {
            return Err(ZipError::InvalidFileHeaderSignature.into());
        }
        let data_pointer = info.header_pointer
            + 30
            + u16::from_le_bytes(buf[26..28].try_into().unwrap()) as u64
            + u16::from_le_bytes(buf[28..30].try_into().unwrap()) as u64;

        Ok(Self {
            io: match info.compression_method {
                CompressionMethod::Store => Compression::Store(IoCursor::new(
                    io,
                    data_pointer,
                    data_pointer + info.compressed_size,
                )?),
                CompressionMethod::Deflate => Compression::Deflate(DeflateDecoder::new(
                    IoCursor::new(io, data_pointer, data_pointer + info.compressed_size)?,
                )),
                CompressionMethod::BZip2 => Compression::BZip2(BzDecoder::new(IoCursor::new(
                    io,
                    data_pointer,
                    data_pointer + info.compressed_size,
                )?)),
                CompressionMethod::Lzma => {
                    io.seek(SeekFrom::Start(data_pointer))?;
                    let buf = io.read_arr::<9>()?;

                    Compression::Xz(XzDecoder::new_stream(
                        IoCursor::new(io, data_pointer + 9, data_pointer + info.compressed_size)?,
                        Stream::new_raw_decoder(
                            Filters::new().lzma1(
                                LzmaOptions::new()
                                    .literal_context_bits((buf[4] % 9) as u32)
                                    .literal_position_bits((buf[4] / 9 % 5) as u32)
                                    .position_bits((buf[4] / 45) as u32)
                                    .dict_size(
                                        u32::from_le_bytes(buf[5..9].try_into().unwrap()).max(4096),
                                    ),
                            ),
                        )
                        .unwrap(),
                    ))
                }
                CompressionMethod::Zstd => Compression::Zstd(
                    ZstdDecoder::new(IoCursor::new(
                        io,
                        data_pointer,
                        data_pointer + info.compressed_size,
                    )?)
                    .unwrap(),
                ),
                CompressionMethod::Xz => Compression::Xz(XzDecoder::new(IoCursor::new(
                    io,
                    data_pointer,
                    data_pointer + info.compressed_size,
                )?)),
                CompressionMethod::Unsupported => {
                    return Err(ZipError::UnsupportedCompressionMethod.into())
                }
            },
            info,
        })
    }

    pub fn seekable(&self) -> bool {
        match self.io {
            Compression::Store(..) => true,
            _ => false,
        }
    }
}

impl<'d, Io: Read> Read for ZipFileReader<'d, Io> {
    fn read(&mut self, buf: &mut [u8]) -> IoResult<usize> {
        match &mut self.io {
            Compression::Store(io) => io.read(buf),
            Compression::Deflate(io) => io.read(buf),
            Compression::BZip2(io) => io.read(buf),
            Compression::Zstd(io) => io.read(buf),
            Compression::Xz(io) => io.read(buf),
        }
    }
}

impl<'d, Io: Read + Seek> Seek for ZipFileReader<'d, Io> {
    fn seek(&mut self, pos: SeekFrom) -> IoResult<u64> {
        match &mut self.io {
            Compression::Store(io) => io.seek(pos),
            _ => Err(IoError::new(
                IoErrorKind::Unsupported,
                ZipError::CompressedDataIsUnseekable,
            )),
        }
    }
}