// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

/*! Interfaces for .deb package files.

The .deb file specification lives at <https://manpages.debian.org/unstable/dpkg-dev/deb.5.en.html>.
*/

use {crate::error::Result, std::io::Read};

pub mod builder;
pub mod reader;

/// Compression format to apply to `.deb` files.
pub enum DebCompression {
    /// Do not compress contents of `.deb` files.
    Uncompressed,
    /// Compress as `.gz` files.
    Gzip,
    /// Compress as `.xz` files using a specified compression level.
    Xz(u32),
    /// Compress as `.zst` files using a specified compression level.
    Zstandard(i32),
}

impl DebCompression {
    /// Obtain the filename extension for this compression format.
    pub fn extension(&self) -> &'static str {
        match self {
            Self::Uncompressed => "",
            Self::Gzip => ".gz",
            Self::Xz(_) => ".xz",
            Self::Zstandard(_) => ".zst",
        }
    }

    /// Compress input data from a reader.
    pub fn compress(&self, reader: &mut impl Read) -> Result<Vec<u8>> {
        let mut buffer = vec![];

        match self {
            Self::Uncompressed => {
                std::io::copy(reader, &mut buffer)?;
            }
            Self::Gzip => {
                let header = libflate::gzip::HeaderBuilder::new().finish();

                let mut encoder = libflate::gzip::Encoder::with_options(
                    &mut buffer,
                    libflate::gzip::EncodeOptions::new().header(header),
                )?;
                std::io::copy(reader, &mut encoder)?;
                encoder.finish().into_result()?;
            }
            Self::Xz(level) => {
                let mut encoder = xz2::write::XzEncoder::new(buffer, *level);
                std::io::copy(reader, &mut encoder)?;
                buffer = encoder.finish()?;
            }
            Self::Zstandard(level) => {
                let mut encoder = zstd::Encoder::new(buffer, *level)?;
                std::io::copy(reader, &mut encoder)?;
                buffer = encoder.finish()?;
            }
        }

        Ok(buffer)
    }
}