use std::fs::{self, File};
use std::io::Write;
use std::path::Path;

use sanctum::crypto::{
    derive_kek, generate_dek, generate_salt, wrap_dek, KdfParams, CHUNK_SIZE, FORMAT_VERSION,
};
use sanctum::storage::Database;
use sanctum::sync::{run_sync, SyncDirection, SyncOptions};

fn create_test_container(path: &Path) -> (Database, [u8; 32]) {
    if path.exists() {
        let _ = fs::remove_file(path);
    }
    let db = Database::open(path).expect("Open database");
    let salt = generate_salt();
    let kdf_params = KdfParams {
        memory_cost: sanctum::crypto::MIN_MEMORY_COST_KIB,
        time_cost: sanctum::crypto::MIN_TIME_COST,
        parallelism: 1,
    };
    let kek = derive_kek("sync_password", &salt, &kdf_params).unwrap();
    let dek = generate_dek();
    let (wrapped_dek, header_nonce, header_tag) = wrap_dek(&kek, &dek).unwrap();
    db.init_schema(&salt, &kdf_params, &wrapped_dek, &header_nonce, &header_tag)
        .unwrap();
    (db, *dek)
}

#[test]
fn test_sync_push_and_pull_basic() {
    let temp_root =
        std::env::temp_dir().join(format!("sanctum_sync_test_{}", rand::random::<u64>()));
    let container_path = temp_root.join("test.sanctum");
    let source_dir = temp_root.join("source");
    let target_dir = temp_root.join("restored");

    fs::create_dir_all(&source_dir).unwrap();
    fs::create_dir_all(source_dir.join("sub")).unwrap();

    // Testdateien anlegen
    fs::write(source_dir.join("file1.txt"), b"Hello Sanctum Sync!").unwrap();
    fs::write(
        source_dir.join("sub").join("file2.bin"),
        vec![0x42u8; 100_000],
    )
    .unwrap();

    let (db, dek) = create_test_container(&container_path);

    // 1. Push
    let mut opts = SyncOptions::default();
    opts.direction = SyncDirection::Push;
    opts.quiet = true;

    let stats = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/Backup",
        &opts,
    )
    .expect("Sync push");

    assert_eq!(stats.files_scanned, 2);
    assert_eq!(stats.files_transferred, 2);
    assert_eq!(stats.files_skipped, 0);

    // 2. Erneuter Push (Fast check / Delta): Muss 0 übertragen, 2 überspringen
    let stats_delta = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/Backup",
        &opts,
    )
    .expect("Sync push delta");

    assert_eq!(stats_delta.files_transferred, 0);
    assert_eq!(stats_delta.files_skipped, 2);

    // 3. Dry-Run mit neuer Datei
    fs::write(source_dir.join("new_file.txt"), b"Brand new file").unwrap();
    let mut dry_opts = opts.clone();
    dry_opts.dry_run = true;

    let stats_dry = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/Backup",
        &dry_opts,
    )
    .expect("Sync push dry-run");

    assert_eq!(stats_dry.files_transferred, 1);
    assert_eq!(stats_dry.files_skipped, 2);

    // Verifizieren, dass new_file.txt im Tresor tatsächlich NICHT existiert
    let node = db
        .resolve_path_in_vault("/Backup/new_file.txt", 0, &dek)
        .unwrap();
    assert!(node.is_none());

    // 4. Pull
    let mut pull_opts = SyncOptions::default();
    pull_opts.direction = SyncDirection::Pull;
    pull_opts.quiet = true;

    let stats_pull = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        "/Backup",
        target_dir.to_str().unwrap(),
        &pull_opts,
    )
    .expect("Sync pull");

    assert_eq!(stats_pull.files_transferred, 2);

    // Inhalt vergleichen
    let c1 = fs::read(target_dir.join("file1.txt")).unwrap();
    assert_eq!(c1, b"Hello Sanctum Sync!");
    let c2 = fs::read(target_dir.join("sub").join("file2.bin")).unwrap();
    assert_eq!(c2, vec![0x42u8; 100_000]);

    // Aufräumen
    let _ = fs::remove_dir_all(&temp_root);
}

#[test]
fn test_sync_multi_megabyte_large_file() {
    let temp_root =
        std::env::temp_dir().join(format!("sanctum_sync_large_{}", rand::random::<u64>()));
    let container_path = temp_root.join("test_large.sanctum");
    let source_dir = temp_root.join("source");
    let target_dir = temp_root.join("restored");

    fs::create_dir_all(&source_dir).unwrap();

    // 3.5 MB große Datei erzeugen (geht über 4 Chunks: 0, 1, 2, 3)
    let large_file_path = source_dir.join("large_payload.bin");
    let mut large_file = File::create(&large_file_path).unwrap();
    let chunk_sample = vec![0xA5u8; CHUNK_SIZE];
    for _ in 0..3 {
        large_file.write_all(&chunk_sample).unwrap();
    }
    large_file.write_all(&vec![0x5Au8; 512 * 1024]).unwrap(); // 3.5 MB
    large_file.flush().unwrap();
    drop(large_file);

    let (db, dek) = create_test_container(&container_path);

    // Push
    let mut opts = SyncOptions::default();
    opts.direction = SyncDirection::Push;
    opts.quiet = true;

    let stats = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/LargeTest",
        &opts,
    )
    .expect("Sync push large");

    assert_eq!(stats.files_transferred, 1);
    assert_eq!(
        stats.bytes_transferred,
        3 * (CHUNK_SIZE as u64) + 512 * 1024
    );

    // Pull
    let mut pull_opts = SyncOptions::default();
    pull_opts.direction = SyncDirection::Pull;
    pull_opts.quiet = true;

    run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        "/LargeTest",
        target_dir.to_str().unwrap(),
        &pull_opts,
    )
    .expect("Sync pull large");

    let restored = fs::read(target_dir.join("large_payload.bin")).unwrap();
    let original = fs::read(&large_file_path).unwrap();
    assert_eq!(restored.len(), original.len());
    assert_eq!(restored, original);

    let _ = fs::remove_dir_all(&temp_root);
}

#[test]
fn test_sync_delete_and_exclude_flags() {
    let temp_root =
        std::env::temp_dir().join(format!("sanctum_sync_flags_{}", rand::random::<u64>()));
    let container_path = temp_root.join("test_flags.sanctum");
    let source_dir = temp_root.join("source");

    fs::create_dir_all(&source_dir).unwrap();
    fs::write(source_dir.join("keep.txt"), b"Keep this").unwrap();
    fs::write(source_dir.join("remove_me.txt"), b"Will be deleted later").unwrap();
    fs::write(source_dir.join("ignore.tmp"), b"Temporary file").unwrap();

    let (db, dek) = create_test_container(&container_path);

    let mut opts = SyncOptions::default();
    opts.direction = SyncDirection::Push;
    opts.exclude_patterns = vec!["*.tmp".to_string()];
    opts.quiet = true;

    // 1. Initialer Push mit Exclude
    let stats = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/Files",
        &opts,
    )
    .unwrap();

    assert_eq!(stats.files_transferred, 2); // keep.txt und remove_me.txt
    assert!(db
        .resolve_path_in_vault("/Files/ignore.tmp", 0, &dek)
        .unwrap()
        .is_none());

    // 2. Lokale Datei löschen und Sync mit --delete ausführen
    fs::remove_file(source_dir.join("remove_me.txt")).unwrap();
    opts.delete = true;

    let stats_del = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/Files",
        &opts,
    )
    .unwrap();

    assert_eq!(stats_del.files_deleted, 1);
    assert!(db
        .resolve_path_in_vault("/Files/remove_me.txt", 0, &dek)
        .unwrap()
        .is_none());
    assert!(db
        .resolve_path_in_vault("/Files/keep.txt", 0, &dek)
        .unwrap()
        .is_some());

    let _ = fs::remove_dir_all(&temp_root);
}

#[test]
fn test_s01_delete_preserves_excluded_files_and_directories() {
    let temp_root =
        std::env::temp_dir().join(format!("sanctum_s01_test_{}", rand::random::<u64>()));
    let container_path = temp_root.join("test_s01.sanctum");
    let source_dir = temp_root.join("source");

    fs::create_dir_all(&source_dir).unwrap();
    fs::create_dir_all(source_dir.join("excluded_dir")).unwrap();
    fs::write(source_dir.join("normal.txt"), b"Normal file").unwrap();
    fs::write(source_dir.join("document.pdf"), b"Important PDF").unwrap();
    fs::write(
        source_dir.join("excluded_dir").join("subfile.txt"),
        b"Subfile in excluded dir",
    )
    .unwrap();

    let (db, dek) = create_test_container(&container_path);

    // 1. Initialer Push ALLER Dateien (ohne Exclude)
    let mut opts = SyncOptions::default();
    opts.direction = SyncDirection::Push;
    opts.quiet = true;

    run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/Data",
        &opts,
    )
    .unwrap();
    assert!(db
        .resolve_path_in_vault("/Data/document.pdf", 0, &dek)
        .unwrap()
        .is_some());
    assert!(db
        .resolve_path_in_vault("/Data/excluded_dir/subfile.txt", 0, &dek)
        .unwrap()
        .is_some());

    // 2. Lokale Kopie von document.pdf und excluded_dir entfernen
    fs::remove_file(source_dir.join("document.pdf")).unwrap();
    fs::remove_dir_all(source_dir.join("excluded_dir")).unwrap();

    // 3. Sync Push mit --delete aber MIT --exclude "*.pdf" und --exclude "excluded_dir*"
    opts.delete = true;
    opts.delete_excluded = false;
    opts.exclude_patterns = vec!["*.pdf".to_string(), "excluded_dir*".to_string()];

    let stats = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/Data",
        &opts,
    )
    .unwrap();
    assert_eq!(
        stats.files_deleted, 0,
        "Ausgeschlossene Dateien/Ordner dürfen NICHT gelöscht werden!"
    );

    // PDF und excluded_dir Teilbaum müssen im Tresor überlebt haben!
    assert!(
        db.resolve_path_in_vault("/Data/document.pdf", 0, &dek)
            .unwrap()
            .is_some(),
        "PDF im Tresor muss überleben"
    );
    assert!(
        db.resolve_path_in_vault("/Data/excluded_dir/subfile.txt", 0, &dek)
            .unwrap()
            .is_some(),
        "Teilbaum in excluded_dir muss überleben"
    );

    // 4. Jetzt Push mit --delete UND --delete-excluded
    opts.delete_excluded = true;
    let stats_del = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/Data",
        &opts,
    )
    .unwrap();
    assert!(
        stats_del.files_deleted >= 2,
        "Mit --delete-excluded müssen die verwaisten ausgeschlossenen Dateien gelöscht werden"
    );
    assert!(
        db.resolve_path_in_vault("/Data/document.pdf", 0, &dek)
            .unwrap()
            .is_none(),
        "PDF muss mit --delete-excluded gelöscht sein"
    );
    assert!(
        db.resolve_path_in_vault("/Data/excluded_dir/subfile.txt", 0, &dek)
            .unwrap()
            .is_none(),
        "excluded_dir Inhalt muss gelöscht sein"
    );

    let _ = fs::remove_dir_all(&temp_root);
}

#[test]
fn test_s01_pull_delete_preserves_local_excluded_and_leak_files() {
    let temp_root =
        std::env::temp_dir().join(format!("sanctum_s01_pull_{}", rand::random::<u64>()));
    let container_path = temp_root.join("test_s01_pull.sanctum");
    let restore_dir = temp_root.join("restored");

    fs::create_dir_all(&restore_dir).unwrap();
    // Lokale Dateien anlegen, die im Vault NICHT existieren: folder.jpg (Leak file) und local_notes.pdf (Ausschluss)
    fs::write(
        restore_dir.join("folder.jpg"),
        b"Album Art or Explorer Cache",
    )
    .unwrap();
    fs::write(restore_dir.join("local_notes.pdf"), b"Private Local Notes").unwrap();

    let (db, dek) = create_test_container(&container_path);

    // Eine Datei im Vault anlegen
    let root_node = db.get_node_by_id_in_vault(1, 0, &dek).unwrap().unwrap();
    let _ = db
        .create_node_in_vault(0, root_node.id, "vault_file.txt", false, &dek)
        .unwrap();

    // Pull mit --delete und --exclude "*.pdf"
    let mut opts = SyncOptions::default();
    opts.direction = SyncDirection::Pull;
    opts.delete = true;
    opts.delete_excluded = false;
    opts.exclude_patterns = vec!["*.pdf".to_string()];
    opts.quiet = true;

    let stats = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        "/",
        restore_dir.to_str().unwrap(),
        &opts,
    )
    .unwrap();
    assert_eq!(
        stats.files_deleted, 0,
        "folder.jpg und local_notes.pdf dürfen bei Pull mit --delete NICHT gelöscht werden!"
    );
    assert!(
        restore_dir.join("folder.jpg").exists(),
        "folder.jpg muss auf dem Host erhalten bleiben"
    );
    assert!(
        restore_dir.join("local_notes.pdf").exists(),
        "local_notes.pdf muss auf dem Host erhalten bleiben"
    );

    // Pull mit --delete UND --delete-excluded
    opts.delete_excluded = true;
    run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        "/",
        restore_dir.to_str().unwrap(),
        &opts,
    )
    .unwrap();
    assert!(
        !restore_dir.join("local_notes.pdf").exists(),
        "local_notes.pdf muss mit --delete-excluded gelöscht werden"
    );

    let _ = fs::remove_dir_all(&temp_root);
}

#[test]
fn test_s02_platform_independent_path_construction_and_traversal_rejection() {
    let temp_root =
        std::env::temp_dir().join(format!("sanctum_s02_test_{}", rand::random::<u64>()));
    let container_path = temp_root.join("test.sanctum");
    let source_dir = temp_root.join("source");
    let target_dir = temp_root.join("restored");

    fs::create_dir_all(&source_dir).unwrap();
    let deep_dir = source_dir.join("level1").join("level2").join("level3");
    fs::create_dir_all(&deep_dir).unwrap();
    fs::write(deep_dir.join("deep_doc.txt"), b"Deeply nested content").unwrap();

    let (db, dek) = create_test_container(&container_path);

    // 1. Push: Übertrage mehrstufige Verzeichnisstruktur in den Tresor
    let mut push_opts = SyncOptions::default();
    push_opts.direction = SyncDirection::Push;
    push_opts.quiet = true;

    run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/MultiLevel",
        &push_opts,
    )
    .expect("Sync push multi-level");

    // 2. Pull: Prüfe, dass mehrstufige Pfade plattformunabhängig rekonstruiert werden
    let mut pull_opts = SyncOptions::default();
    pull_opts.direction = SyncDirection::Pull;
    pull_opts.quiet = true;

    run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        "/MultiLevel",
        target_dir.to_str().unwrap(),
        &pull_opts,
    )
    .expect("Sync pull multi-level");

    let restored_file = target_dir
        .join("level1")
        .join("level2")
        .join("level3")
        .join("deep_doc.txt");
    assert!(
        restored_file.exists(),
        "Mehrstufige Datei muss korrekt auf dem Host angelegt worden sein"
    );
    assert_eq!(fs::read(restored_file).unwrap(), b"Deeply nested content");

    // 3. Traversal-Abwehr: Bösartiger Knoten mit relativem Ausbruchsversuch
    // Simuliere manipulierten Knoten im Tresor
    {
        let conn = rusqlite::Connection::open(&container_path).unwrap();
        // Erstelle Knoten mit manipuliertem Namen '../evil.txt'
        conn.execute(
            "INSERT INTO nodes (id, parent_id, name, is_dir, size, created_at, modified_at, is_carrier)
             VALUES (9999, 1, '../evil.txt', 0, 10, 100, 100, 0)",
            [],
        )
        .unwrap();
    }

    let malicious_target = temp_root.join("malicious_target");
    fs::create_dir_all(&malicious_target).unwrap();

    let pull_res = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        "/",
        malicious_target.to_str().unwrap(),
        &pull_opts,
    );

    assert!(
        pull_res.is_err(),
        "Sync Pull muss bei manipuliertem Traversal-Pfad abbrechen"
    );
    let err_msg = pull_res.unwrap_err().to_string();
    assert!(
        err_msg.contains("Path traversal")
            || err_msg.contains("Ungültiger Dateiname")
            || err_msg.contains("unzulässige Trennzeichen"),
        "Fehlermeldung muss Traversal-Erkennung ausweisen: {}",
        err_msg
    );
    assert!(
        !temp_root.join("evil.txt").exists(),
        "Es darf niemals eine Datei außerhalb des Zielverzeichnisses erzeugt werden"
    );

    // Aufräumen
    let _ = fs::remove_dir_all(&temp_root);
}

#[test]
fn test_s03_symlink_skipping_and_cycle_protection() {
    let temp_root =
        std::env::temp_dir().join(format!("sanctum_s03_test_{}", rand::random::<u64>()));
    let container_path = temp_root.join("test.sanctum");
    let source_dir = temp_root.join("source");
    let sub_dir = source_dir.join("sub");

    fs::create_dir_all(&sub_dir).unwrap();
    fs::write(source_dir.join("regular.txt"), b"Regular content").unwrap();

    // Erzeuge eine rekursive Verknüpfung (Junction unter Windows / Symlink unter Unix)
    let loop_path = sub_dir.join("cycle");
    #[cfg(windows)]
    {
        let status = std::process::Command::new("powershell")
            .args([
                "-Command",
                &format!(
                    "New-Item -ItemType Junction -Path '{}' -Target '{}'",
                    loop_path.display(),
                    source_dir.display()
                ),
            ])
            .status();
        if status.is_err() || !status.unwrap().success() {
            eprintln!("Junction creation skipped (not supported in current environment)");
            let _ = fs::remove_dir_all(&temp_root);
            return;
        }
    }
    #[cfg(unix)]
    {
        if let Err(e) = std::os::unix::fs::symlink(&source_dir, &loop_path) {
            eprintln!("Symlink creation skipped: {e}");
            let _ = fs::remove_dir_all(&temp_root);
            return;
        }
    }

    let (db, dek) = create_test_container(&container_path);

    let mut opts = SyncOptions::default();
    opts.direction = SyncDirection::Push;
    opts.quiet = true;

    // Ohne S-03 Fix würde der Sync endlos in die Schleife laufen und mit Stack-Overflow abstürzen.
    // Mit Fix wird der Symlink übersprungen und gezählt.
    let stats = run_sync(
        &db,
        0,
        &dek,
        FORMAT_VERSION,
        source_dir.to_str().unwrap(),
        "/SafePush",
        &opts,
    )
    .expect("Sync push must succeed despite symlink cycle");

    assert_eq!(
        stats.files_transferred, 1,
        "Nur reguläre Datei darf übertragen werden"
    );
    assert!(
        stats.files_skipped_symlinks >= 1,
        "Symlink/Junction muss erkannt und in files_skipped_symlinks gezählt werden"
    );

    // Aufräumen: Unter Windows Junction vor dem remove_dir_all entfernen
    #[cfg(windows)]
    {
        let _ = std::process::Command::new("powershell")
            .args([
                "-Command",
                &format!("[System.IO.Directory]::Delete('{}')", loop_path.display()),
            ])
            .status();
    }
    let _ = fs::remove_dir_all(&temp_root);
}