use crate::driver::FileDriver;
use crate::utils::{IoCursor, ReadUtils};
use crate::zip::encryption::WeakDecoder;
use crate::zip::{CompressionMethod, EncryptionMethod, 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 Encryption<Io: Read> {
    None(Io),
    Weak(WeakDecoder<Io>),
}

impl<Io: Read> Encryption<Io> {
    pub fn new(io: Io, info: &ZipFileInfo, password: Option<&[u8]>) -> ZipResult<Self> {
        Ok(match info.encryption_method {
            EncryptionMethod::None => Self::None(io),
            EncryptionMethod::Weak(check) => Self::Weak(WeakDecoder::new(
                io,
                check,
                password.ok_or(ZipError::PasswordIsNotSpecified)?,
            )?),
            EncryptionMethod::Unsupported => {
                return Err(ZipError::UnsupportedEncryptionMethod.into())
            }
        })
    }
}

impl<Io: Read> Read for Encryption<Io> {
    fn read(&mut self, buf: &mut [u8]) -> IoResult<usize> {
        match self {
            Self::None(io) => io.read(buf),
            Self::Weak(io) => io.read(buf),
        }
    }
}

impl<Io: Read + Seek> Seek for Encryption<Io> {
    fn seek(&mut self, pos: SeekFrom) -> IoResult<u64> {
        match self {
            Self::None(io) => io.seek(pos),
            _ => Err(IoError::new(
                IoErrorKind::Unsupported,
                ZipError::EncryptedDataIsUnseekable,
            )),
        }
    }
}

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

impl<Io: Read + Seek> Compression<Io> {
    pub fn new(mut io: Io, info: &ZipFileInfo) -> ZipResult<Self> {
        Ok(match info.compression_method {
            CompressionMethod::Store => Self::Store(io),
            CompressionMethod::Deflate => Self::Deflate(DeflateDecoder::new(io)),
            CompressionMethod::BZip2 => Self::BZip2(BzDecoder::new(io)),
            CompressionMethod::Lzma => {
                let buf = io.read_arr::<9>()?;
                Compression::Xz(XzDecoder::new_stream(
                    io,
                    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 => Self::Zstd(ZstdDecoder::new(io)?),
            CompressionMethod::Xz => Self::Xz(XzDecoder::new(io)),
            CompressionMethod::Unsupported(id) => {
                return Err(ZipError::UnsupportedCompressionMethod(id).into())
            }
        })
    }
}

impl<Io: Read> Read for Compression<Io> {
    fn read(&mut self, buf: &mut [u8]) -> IoResult<usize> {
        match self {
            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<Io: Read + Seek> Seek for Compression<Io> {
    fn seek(&mut self, pos: SeekFrom) -> IoResult<u64> {
        match self {
            Compression::Store(io) => io.seek(pos),
            _ => Err(IoError::new(
                IoErrorKind::Unsupported,
                ZipError::CompressedDataIsUnseekable,
            )),
        }
    }
}

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

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

impl<'d, Io: Read + Seek> ZipFileReader<'d, Io> {
    pub(crate) fn new(
        io: &'d mut Io,
        info: &'d ZipFileInfo,
        password: Option<&[u8]>,
    ) -> 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: Compression::new(
                Encryption::new(
                    IoCursor::new(io, data_pointer, data_pointer + info.compressed_size)?,
                    info,
                    password,
                )?,
                info,
            )?,
            info,
        })
    }

    pub fn info(&self) -> &ZipFileInfo {
        self.info
    }

    pub fn is_seekable(&self) -> bool {
        match self.io {
            Compression::Store(Encryption::None(..)) => true,
            _ => false,
        }
    }
}

impl<'d, Io: Read> Read for ZipFileReader<'d, Io> {
    fn read(&mut self, buf: &mut [u8]) -> IoResult<usize> {
        self.io.read(buf)
    }
}

impl<'d, Io: Read + Seek> Seek for ZipFileReader<'d, Io> {
    fn seek(&mut self, pos: SeekFrom) -> IoResult<u64> {
        self.io.seek(pos)
    }
}