extern crate std;
use crate as zstd_safe;

use self::std::vec::Vec;

const INPUT: &[u8] = b"Rust is a multi-paradigm system programming language focused on safety, especially safe concurrency. Rust is syntactically similar to C++, but is designed to provide better memory safety while maintaining high performance.";
const LONG_CONTENT: &str = include_str!("lib.rs");

#[cfg(feature = "std")]
#[test]
fn test_simple_cycle() {
    let mut buffer = std::vec![0u8; 256];
    let written = zstd_safe::compress(&mut buffer, INPUT, 3).unwrap();
    let compressed = &buffer[..written];

    let mut buffer = std::vec![0u8; 256];
    let written = zstd_safe::decompress(&mut buffer, compressed).unwrap();
    let decompressed = &buffer[..written];

    assert_eq!(INPUT, decompressed);
}

#[test]
fn test_cctx_cycle() {
    let mut buffer = std::vec![0u8; 256];
    let mut cctx = zstd_safe::CCtx::default();
    let written =
        zstd_safe::compress_cctx(&mut cctx, &mut buffer[..], INPUT, 1)
            .unwrap();
    let compressed = &buffer[..written];

    let mut dctx = zstd_safe::DCtx::default();
    let mut buffer = std::vec![0u8; 256];
    let written =
        zstd_safe::decompress_dctx(&mut dctx, &mut buffer[..], compressed)
            .unwrap();
    let decompressed = &buffer[..written];

    assert_eq!(INPUT, decompressed);
}

#[test]
fn test_dictionary() {
    // Prepare some content to train the dictionary.
    let bytes = LONG_CONTENT.as_bytes();
    let line_sizes: Vec<usize> =
        LONG_CONTENT.lines().map(|line| line.len() + 1).collect();

    // Train the dictionary
    let mut dict_buffer = std::vec![0u8; 100_000];
    let written =
        zstd_safe::train_from_buffer(&mut dict_buffer[..], bytes, &line_sizes)
            .unwrap();
    let dict_buffer = &dict_buffer[..written];

    // Create pre-hashed dictionaries for (de)compression
    let cdict = zstd_safe::create_cdict(dict_buffer, 3);
    let ddict = zstd_safe::create_ddict(dict_buffer);

    // Compress data
    let mut cctx = zstd_safe::CCtx::default();
    zstd_safe::cctx_ref_cdict(&mut cctx, &cdict).unwrap();

    let mut buffer = std::vec![0u8; 1024 * 1024];
    // First, try to compress without a dict
    let big_written = zstd_safe::compress(&mut buffer[..], bytes, 3).unwrap();

    let written = zstd_safe::compress2(&mut cctx, &mut buffer[..], bytes)
        .map_err(zstd_safe::get_error_name)
        .unwrap();

    assert!(big_written > written);
    let compressed = &buffer[..written];

    // Decompress data
    let mut dctx = zstd_safe::DCtx::default();
    zstd_safe::dctx_ref_ddict(&mut dctx, &ddict).unwrap();

    let mut buffer = std::vec![0u8; 1024 * 1024];
    let written =
        zstd_safe::decompress_dctx(&mut dctx, &mut buffer[..], compressed)
            .map_err(zstd_safe::get_error_name)
            .unwrap();
    let decompressed = &buffer[..written];

    // Profit!
    assert_eq!(bytes, decompressed);
}

#[test]
fn test_checksum() {
    let mut buffer = std::vec![0u8; 256];
    let mut cctx = zstd_safe::CCtx::default();
    zstd_safe::cctx_set_parameter(
        &mut cctx,
        zstd_safe::CParameter::ChecksumFlag(true),
    )
    .unwrap();
    let written =
        zstd_safe::compress2(&mut cctx, &mut buffer[..], INPUT).unwrap();
    let compressed = &mut buffer[..written];

    let mut dctx = zstd_safe::DCtx::default();
    let mut buffer = std::vec![0u8; 1024*1024];
    let written =
        zstd_safe::decompress_dctx(&mut dctx, &mut buffer[..], compressed)
            .map_err(zstd_safe::get_error_name)
            .unwrap();
    let decompressed = &buffer[..written];

    assert_eq!(INPUT, decompressed);

    // Now try again with some corruption
    // TODO: Find a mutation that _wouldn't_ be detected without checksums.
    // (Most naive changes already trigger a "corrupt block" error.)
    if let Some(last) = compressed.last_mut() {
        *last = last.saturating_sub(1);
    }
    let err =
        zstd_safe::decompress_dctx(&mut dctx, &mut buffer[..], compressed)
            .map_err(zstd_safe::get_error_name)
            .err()
            .unwrap();
    // The error message will complain about the checksum.
    assert!(err.contains("checksum"));
}

#[cfg(feature="experimental")]
#[test]
fn test_upper_bound() {
    let mut buffer = std::vec![0u8; 256];

    assert!(zstd_safe::decompress_bound(&buffer).is_err());

    let written = zstd_safe::compress(&mut buffer, INPUT, 3).unwrap();
    let compressed = &buffer[..written];

    assert_eq!(zstd_safe::decompress_bound(&compressed), Ok(INPUT.len() as u64));
}