ouch/tests/compress_and_decompress.rs

use std::{
    env, fs,
    io::prelude::*,
    path::{Path, PathBuf},
};

use ouch::{cli::Command, commands::run, oof};
use rand::{rngs::SmallRng, RngCore, SeedableRng};
use tempdir::TempDir;

#[test]
/// Tests each format that supports multiple files with random input.
/// TODO: test the remaining formats.
fn test_each_format() {
    test_compression_and_decompression("tar");
    test_compression_and_decompression("tar.gz");
    test_compression_and_decompression("tar.bz");
    test_compression_and_decompression("tar.bz2");
    test_compression_and_decompression("tar.xz");
    test_compression_and_decompression("tar.lz");
    test_compression_and_decompression("tar.lzma");
    test_compression_and_decompression("zip");
    test_compression_and_decompression("zip.gz");
    test_compression_and_decompression("zip.bz");
    test_compression_and_decompression("zip.bz2");
    test_compression_and_decompression("zip.xz");
    test_compression_and_decompression("zip.lz");
    test_compression_and_decompression("zip.lzma");

    // Why not
    test_compression_and_decompression("tar.gz.gz.gz.gz.gz.gz.gz.gz.gz.gz.gz.gz.gz.gz.gz.gz.gz.gz.lz.lz.lz.lz.lz.lz.lz.lz.lz.lz.bz.bz.bz.bz.bz.bz.bz");
}

type FileContent = Vec<u8>;

fn test_compression_and_decompression(format: &str) -> bool {
    let mut rng = SmallRng::from_entropy();

    // System temporary directory depends on the platform
    // For linux it is /tmp
    let system_tmp = env::temp_dir();
    // Create a folder that will be deleted on drop
    let testing_dir = String::from("ouch-testing-") + format;
    let testing_dir = TempDir::new_in(system_tmp, &testing_dir).expect("Could not create tempdir");
    let testing_dir = testing_dir.path();

    // Quantity of compressed files vary from 1 to 10
    let quantity_of_files = rng.next_u32() % 10 + 1;

    let contents_of_files: Vec<FileContent> =
        (0..quantity_of_files).map(|_| generate_random_file_content(&mut rng)).collect();

    let mut file_paths = create_files(&testing_dir, &contents_of_files);
    let compressed_archive_path = compress_files(&testing_dir, &file_paths, &format);
    let mut extracted_paths = extract_files(&compressed_archive_path);

    // // If you want to visualize the compressed and extracted files in the temporary directory
    // // before their auto-destruction:
    // dbg!(&testing_dir);
    // std::thread::sleep(std::time::Duration::from_secs(60));

    file_paths.sort();
    extracted_paths.sort();

    assert_correct_paths(&file_paths, &extracted_paths);
    compare_file_contents(&extracted_paths, &contents_of_files)
}

// Crate file contents from 1024 up to 8192 random bytes
fn generate_random_file_content(rng: &mut impl RngCore) -> FileContent {
    let quantity = 1024 + rng.next_u32() % (8192 - 1024);
    let mut vec = vec![0; quantity as usize];
    rng.fill_bytes(&mut vec);
    vec
}

// Create files using the indexes as file names (eg. 0, 1, 2 and 3)
// Returns the paths
fn create_files(at: &Path, contents: &[FileContent]) -> Vec<PathBuf> {
    contents
        .iter()
        .enumerate()
        .map(|(i, content)| {
            let path = at.join(i.to_string());
            let mut file = fs::File::create(&path).expect("Could not create dummy test file");
            file.write_all(content).expect("Could not write to dummy test file");
            path
        })
        .collect()
}

fn compress_files(at: &Path, paths_to_compress: &[PathBuf], format: &str) -> PathBuf {
    let archive_path = String::from("archive.") + format;
    let archive_path = at.join(archive_path);

    let command = Command::Compress {
        files: paths_to_compress.to_vec(),
        output_path: archive_path.to_path_buf(),
    };
    run(command, &oof::Flags::default()).expect("Failed to compress test dummy files");

    archive_path
}

fn extract_files(archive_path: &Path) -> Vec<PathBuf> {
    // We will extract in the same folder as the archive
    // If the archive is at:
    //   /tmp/ouch-testing-tar.Rbq4DusBrtF8/archive.tar
    // Then the extraction_output_folder will be:
    //   /tmp/ouch-testing-tar.Rbq4DusBrtF8/extraction_results/
    let mut extraction_output_folder = archive_path.to_path_buf();
    // Remove the name of the extracted archive
    assert!(extraction_output_folder.pop());
    // Add the suffix "results"
    extraction_output_folder.push("extraction_results");

    let command = Command::Decompress {
        files: vec![archive_path.to_owned()],
        output_folder: Some(extraction_output_folder.clone()),
    };
    run(command, &oof::Flags::default()).expect("Failed to extract");

    fs::read_dir(extraction_output_folder)
        .unwrap()
        .map(Result::unwrap)
        .map(|entry| entry.path())
        .collect()
}

fn assert_correct_paths(original: &[PathBuf], extracted: &[PathBuf]) {
    assert_eq!(original.len(), extracted.len());
    for (original, extracted) in original.iter().zip(extracted) {
        assert_eq!(original.file_name(), extracted.file_name());
    }
}

fn compare_file_contents(extracted: &[PathBuf], contents: &[FileContent]) -> bool {
    for (extracted_path, expected_content) in extracted.iter().zip(contents) {
        let read_content = fs::read(extracted_path).expect("Failed to read from file");
        if &read_content != expected_content {
            return false;
        }
    }
    true
}