blazehash 0.2.3

#![cfg(feature = "gpu")]

use blazehash::gpu::config::{GpuConfig, GpuConfigState};
use tempfile::TempDir;

fn temp_config_path() -> (TempDir, std::path::PathBuf) {
    let dir = TempDir::new().unwrap();
    let path = dir.path().join("config.toml");
    (dir, path)
}

#[test]
fn test_config_no_file_returns_none() {
    let (_dir, path) = temp_config_path();
    let config = GpuConfig::load(&path);
    assert!(config.is_none(), "no config file → no config");
}

#[test]
fn test_config_write_and_load_roundtrip() {
    let (_dir, path) = temp_config_path();
    let cfg = GpuConfig {
        device: "NVIDIA RTX 3090".to_string(),
        calibrated: "2026-04-09".to_string(),
        threshold_single_mb: 48,
        threshold_multi_mb: 3,
        gpu_enabled: true,
    };
    cfg.save(&path).unwrap();
    let loaded = GpuConfig::load(&path).unwrap();
    assert_eq!(loaded.device, "NVIDIA RTX 3090");
    assert_eq!(loaded.threshold_single_mb, 48);
    assert!(loaded.gpu_enabled);
}

#[test]
fn test_config_corrupted_returns_none() {
    let (_dir, path) = temp_config_path();
    std::fs::write(&path, b"not valid toml {{{{").unwrap();
    let config = GpuConfig::load(&path);
    assert!(config.is_none(), "corrupted config → treat as missing");
}

#[test]
fn test_state_no_config_triggers_calibration() {
    let (_dir, path) = temp_config_path();
    let state = GpuConfigState::resolve(None, Some("NVIDIA RTX 3090"), &path);
    assert_eq!(state, GpuConfigState::NeedsCalibration);
}

#[test]
fn test_state_same_device_enabled_returns_use_thresholds() {
    let (_dir, path) = temp_config_path();
    let cfg = GpuConfig {
        device: "NVIDIA RTX 3090".to_string(),
        calibrated: "2026-04-09".to_string(),
        threshold_single_mb: 48,
        threshold_multi_mb: 3,
        gpu_enabled: true,
    };
    cfg.save(&path).unwrap();
    let state = GpuConfigState::resolve(GpuConfig::load(&path), Some("NVIDIA RTX 3090"), &path);
    assert_eq!(
        state,
        GpuConfigState::UseThresholds {
            single_mb: 48,
            multi_mb: 3
        }
    );
}

#[test]
fn test_state_same_device_disabled_returns_skip() {
    let (_dir, path) = temp_config_path();
    let cfg = GpuConfig {
        device: "Intel UHD 630".to_string(),
        calibrated: "2026-04-09".to_string(),
        threshold_single_mb: 999,
        threshold_multi_mb: 999,
        gpu_enabled: false,
    };
    cfg.save(&path).unwrap();
    let state = GpuConfigState::resolve(GpuConfig::load(&path), Some("Intel UHD 630"), &path);
    assert_eq!(state, GpuConfigState::Skip);
}

#[test]
fn test_state_different_device_triggers_calibration() {
    let (_dir, path) = temp_config_path();
    let cfg = GpuConfig {
        device: "Old GPU".to_string(),
        calibrated: "2026-04-09".to_string(),
        threshold_single_mb: 48,
        threshold_multi_mb: 3,
        gpu_enabled: true,
    };
    cfg.save(&path).unwrap();
    let state = GpuConfigState::resolve(GpuConfig::load(&path), Some("New GPU"), &path);
    assert_eq!(state, GpuConfigState::NeedsCalibration);
}

#[test]
fn test_state_no_gpu_adapter_returns_skip_leaves_config() {
    let (_dir, path) = temp_config_path();
    let cfg = GpuConfig {
        device: "NVIDIA RTX 3090".to_string(),
        calibrated: "2026-04-09".to_string(),
        threshold_single_mb: 48,
        threshold_multi_mb: 3,
        gpu_enabled: true,
    };
    cfg.save(&path).unwrap();
    // GPU absent (adapter = None) — config should be untouched
    let state = GpuConfigState::resolve(GpuConfig::load(&path), None, &path);
    assert_eq!(state, GpuConfigState::Skip);
    // Config still on disk, unmodified
    let reloaded = GpuConfig::load(&path).unwrap();
    assert_eq!(reloaded.device, "NVIDIA RTX 3090");
}

#[test]
fn test_no_calibrate_flag_returns_conservative_defaults() {
    let state = GpuConfigState::resolve_no_calibrate(Some("NVIDIA RTX 3090"));
    assert_eq!(
        state,
        GpuConfigState::UseThresholds {
            single_mb: blazehash::gpu::config::DEFAULT_THRESHOLD_SINGLE_MB,
            multi_mb: blazehash::gpu::config::DEFAULT_THRESHOLD_MULTI_MB,
        }
    );
}

#[test]
fn test_backend_detect_returns_option() {
    // On headless CI with no GPU, returns None gracefully.
    // On a machine with a GPU, returns Some.
    // Either way: must not panic.
    let backend = blazehash::gpu::backend::GpuBackend::detect();
    if let Some(b) = backend {
        assert!(!b.adapter_name().is_empty());
    }
}

#[test]
fn test_backend_skips_software_renderers() {
    // If detect() returns Some, the adapter must not be a known SW renderer.
    let backend = blazehash::gpu::backend::GpuBackend::detect();
    if let Some(b) = backend {
        let name = b.adapter_name().to_lowercase();
        assert!(!name.contains("warp"), "WARP is a software renderer");
        assert!(
            !name.contains("llvmpipe"),
            "llvmpipe is a software renderer"
        );
        assert!(
            !name.contains("software"),
            "software renderer must be skipped"
        );
    }
}

#[test]
fn test_gpu_sha256_empty_input() {
    let Some(backend) = blazehash::gpu::backend::GpuBackend::detect() else {
        eprintln!("No GPU — skipping GPU sha256 test");
        return;
    };
    let hasher = blazehash::gpu::sha256::GpuSha256::new(&backend);
    let result = hasher.hash(b"");
    assert_eq!(
        result,
        "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
    );
}

#[test]
fn test_gpu_sha256_abc() {
    let Some(backend) = blazehash::gpu::backend::GpuBackend::detect() else {
        return;
    };
    let hasher = blazehash::gpu::sha256::GpuSha256::new(&backend);
    let result = hasher.hash(b"abc");
    assert_eq!(
        result,
        "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad"
    );
}

#[test]
fn test_gpu_sha256_matches_cpu_for_various_sizes() {
    use sha2::{Digest, Sha256};

    let Some(backend) = blazehash::gpu::backend::GpuBackend::detect() else {
        return;
    };
    let hasher = blazehash::gpu::sha256::GpuSha256::new(&backend);

    for size in [0usize, 1, 55, 56, 63, 64, 128, 1023, 4096] {
        let data: Vec<u8> = (0..size).map(|i| (i % 251) as u8).collect();
        let gpu_result = hasher.hash(&data);
        let cpu_result = hex::encode(Sha256::digest(&data));
        assert_eq!(gpu_result, cpu_result, "mismatch at size={size}");
    }
}

#[test]
fn test_gpu_sha256_large_file_matches_cpu() {
    use sha2::{Digest, Sha256};

    let Some(backend) = blazehash::gpu::backend::GpuBackend::detect() else {
        return;
    };
    let hasher = blazehash::gpu::sha256::GpuSha256::new(&backend);

    let data = vec![0x42u8; 1024 * 1024]; // 1 MiB
    let gpu_result = hasher.hash(&data);
    let cpu_result = hex::encode(Sha256::digest(&data));
    assert_eq!(gpu_result, cpu_result);
}

#[test]
fn test_gpu_md5_empty_input() {
    let Some(backend) = blazehash::gpu::backend::GpuBackend::detect() else {
        eprintln!("No GPU — skipping GPU md5 test");
        return;
    };
    let hasher = blazehash::gpu::md5::GpuMd5::new(&backend);
    let result = hasher.hash(b"");
    // MD5("") = d41d8cd98f00b204e9800998ecf8427e
    assert_eq!(result, "d41d8cd98f00b204e9800998ecf8427e");
}

#[test]
fn test_gpu_md5_abc() {
    let Some(backend) = blazehash::gpu::backend::GpuBackend::detect() else {
        return;
    };
    let hasher = blazehash::gpu::md5::GpuMd5::new(&backend);
    let result = hasher.hash(b"abc");
    // MD5("abc") = 900150983cd24fb0d6963f7d28e17f72
    assert_eq!(result, "900150983cd24fb0d6963f7d28e17f72");
}

#[test]
fn test_gpu_md5_matches_cpu_for_various_sizes() {
    use md5::{Digest, Md5};

    let Some(backend) = blazehash::gpu::backend::GpuBackend::detect() else {
        return;
    };
    let hasher = blazehash::gpu::md5::GpuMd5::new(&backend);

    for size in [0usize, 1, 55, 56, 63, 64, 128, 1023, 4096] {
        let data: Vec<u8> = (0..size).map(|i| (i % 251) as u8).collect();
        let gpu_result = hasher.hash(&data);
        let cpu_result = hex::encode(Md5::digest(&data));
        assert_eq!(gpu_result, cpu_result, "mismatch at size={size}");
    }
}

#[test]
fn test_gpu_md5_large_file_matches_cpu() {
    use md5::{Digest, Md5};

    let Some(backend) = blazehash::gpu::backend::GpuBackend::detect() else {
        return;
    };
    let hasher = blazehash::gpu::md5::GpuMd5::new(&backend);

    let data = vec![0x42u8; 1024 * 1024]; // 1 MiB
    let gpu_result = hasher.hash(&data);
    let cpu_result = hex::encode(Md5::digest(&data));
    assert_eq!(gpu_result, cpu_result);
}

// ---- Task 13: GPU threshold decision function ----

use blazehash::algorithm::Algorithm;
use blazehash::gpu::threshold::{should_use_gpu, GPU_ALGOS};

#[test]
fn test_gpu_algos_excludes_blake3() {
    assert!(
        !GPU_ALGOS.contains(&Algorithm::Blake3),
        "BLAKE3 must not be in GPU_ALGOS"
    );
    assert!(
        GPU_ALGOS.contains(&Algorithm::Sha256),
        "SHA-256 must be in GPU_ALGOS"
    );
    assert!(
        GPU_ALGOS.contains(&Algorithm::Md5),
        "MD5 must be in GPU_ALGOS"
    );
}

#[test]
fn test_should_use_gpu_skip_state_always_false() {
    let state = GpuConfigState::Skip;
    assert!(!should_use_gpu(100, &[Algorithm::Sha256], &state));
    assert!(!should_use_gpu(100, &[Algorithm::Md5], &state));
}

#[test]
fn test_should_use_gpu_needs_calibration_always_false() {
    let state = GpuConfigState::NeedsCalibration;
    assert!(!should_use_gpu(100, &[Algorithm::Sha256], &state));
}

#[test]
fn test_should_use_gpu_blake3_only_always_false() {
    let state = GpuConfigState::UseThresholds {
        single_mb: 10,
        multi_mb: 3,
    };
    // BLAKE3 is not GPU-eligible — never use GPU even if file is huge
    assert!(!should_use_gpu(1000, &[Algorithm::Blake3], &state));
}

#[test]
fn test_should_use_gpu_single_algo_below_threshold() {
    let state = GpuConfigState::UseThresholds {
        single_mb: 48,
        multi_mb: 3,
    };
    // 10 MB < 48 MB threshold — use CPU
    assert!(!should_use_gpu(10, &[Algorithm::Sha256], &state));
}

#[test]
fn test_should_use_gpu_single_algo_above_threshold() {
    let state = GpuConfigState::UseThresholds {
        single_mb: 48,
        multi_mb: 3,
    };
    // 100 MB > 48 MB threshold — use GPU
    assert!(should_use_gpu(100, &[Algorithm::Sha256], &state));
}

#[test]
fn test_should_use_gpu_multi_algo_below_threshold() {
    let state = GpuConfigState::UseThresholds {
        single_mb: 48,
        multi_mb: 3,
    };
    // 1 MB < 3 MB multi threshold with 2 GPU-eligible algos — use CPU
    assert!(!should_use_gpu(
        1,
        &[Algorithm::Sha256, Algorithm::Md5],
        &state
    ));
}

#[test]
fn test_should_use_gpu_multi_algo_above_threshold() {
    let state = GpuConfigState::UseThresholds {
        single_mb: 48,
        multi_mb: 3,
    };
    // 5 MB > 3 MB multi threshold with 2 GPU-eligible algos — use GPU
    assert!(should_use_gpu(
        5,
        &[Algorithm::Sha256, Algorithm::Md5],
        &state
    ));
}

#[test]
fn test_should_use_gpu_mixed_algos_counts_only_gpu_eligible() {
    let state = GpuConfigState::UseThresholds {
        single_mb: 48,
        multi_mb: 3,
    };
    // Blake3 + Sha256 + Md5 — only 2 are GPU-eligible (Sha256, Md5)
    // 2 eligible algos → multi path: 5 MB > 3 MB → GPU
    assert!(should_use_gpu(
        5,
        &[Algorithm::Blake3, Algorithm::Sha256, Algorithm::Md5],
        &state
    ));
}

// ---- Task 14: GPU integration in hash_file ----

#[test]
fn test_gpu_hash_file_sha256_matches_cpu() {
    use blazehash::algorithm::Algorithm;
    use blazehash::hash::hash_file;
    use std::io::Write;
    use tempfile::NamedTempFile;

    // Only run this test if a GPU is available
    if blazehash::gpu::backend::GpuBackend::detect().is_none() {
        eprintln!("No GPU — skipping hash_file GPU integration test");
        return;
    }

    let mut f = NamedTempFile::new().unwrap();
    // 1 MiB file — verify correctness regardless of which path is taken.
    f.write_all(&vec![0x77u8; 1024 * 1024]).unwrap();
    f.flush().unwrap();

    let result1 = hash_file(f.path(), &[Algorithm::Sha256], false, false).unwrap();
    // Call again — must produce identical result (GPU or CPU, both correct)
    let result2 = hash_file(f.path(), &[Algorithm::Sha256], false, false).unwrap();
    assert_eq!(
        result1.hashes[&Algorithm::Sha256],
        result2.hashes[&Algorithm::Sha256],
        "hash_file must be deterministic"
    );
    assert_eq!(result1.hashes[&Algorithm::Sha256].len(), 64);
}