use coracle_lib::events::{EventContent, OwnedEvent};
use coracle_lib::keys::SecretKey;
use coracle_lib::pow::{get_leading_zero_bits, get_pow, mine_pow, mine_pow_batch};
use coracle_lib::tags::{Tag, Tags};

fn fixed_secret() -> SecretKey {
    let bytes: [u8; 32] = [
        1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
        25, 26, 27, 28, 29, 30, 31, 32,
    ];
    SecretKey::from_hex(&hex::encode(bytes)).unwrap()
}

fn test_event() -> OwnedEvent {
    EventContent::new("hello nostr", Tags::new())
        .kind(1)
        .stamp(1_700_000_000)
        .own(fixed_secret().public_key())
}

// --- get_leading_zero_bits ---

#[test]
fn leading_zeros_empty_slice() {
    assert_eq!(get_leading_zero_bits(&[]), 0);
}

#[test]
fn leading_zeros_all_zeros() {
    assert_eq!(get_leading_zero_bits(&[0, 0, 0, 0]), 32);
}

#[test]
fn leading_zeros_first_byte_nonzero() {
    assert_eq!(get_leading_zero_bits(&[0x80, 0x00]), 0);
    assert_eq!(get_leading_zero_bits(&[0x01, 0x00]), 7);
    assert_eq!(get_leading_zero_bits(&[0x0F]), 4);
}

#[test]
fn leading_zeros_with_zero_prefix() {
    assert_eq!(get_leading_zero_bits(&[0x00, 0x01]), 15);
    assert_eq!(get_leading_zero_bits(&[0x00, 0x00, 0x80]), 16);
    assert_eq!(get_leading_zero_bits(&[0x00, 0x00, 0x00, 0x01]), 31);
}

#[test]
fn leading_zeros_known_hash() {
    // "000006d8..." → 0x00, 0x00, 0x06 → 16 + 5 = 21
    let hash = hex::decode("000006d8c378af1779d2feebc7603a125d99eca0ccf1085959b307f64e5dd358")
        .unwrap();
    assert_eq!(get_leading_zero_bits(&hash), 21);
}

// --- get_pow (free function) ---

#[test]
fn get_pow_returns_min_of_hash_and_claim() {
    let event = test_event();
    let hashed = mine_pow(&event, 8);
    // The free function should return at least 8
    assert!(get_pow(&hashed.id, &hashed.tags) >= 8);
}

#[test]
fn get_pow_zero_without_nonce_tag() {
    let hashed = test_event().hash();
    assert_eq!(get_pow(&hashed.id, &hashed.tags), 0);
}

#[test]
fn get_pow_capped_by_claimed_difficulty() {
    // Mine at difficulty 4 — even if hash has more leading zeros,
    // get_pow returns at most 4
    let event = test_event();
    let hashed = mine_pow(&event, 4);
    assert!(get_pow(&hashed.id, &hashed.tags) >= 4);
    // Actual leading zeros might exceed 4, but get_pow is min(leading, claimed)
    assert_eq!(get_pow(&hashed.id, &hashed.tags), 4);
}

// --- HashedEvent::get_pow method ---

#[test]
fn hashed_event_get_pow_method() {
    let event = test_event();
    let hashed = mine_pow(&event, 8);
    assert!(hashed.get_pow() >= 8);
}

#[test]
fn hashed_event_get_pow_zero_without_nonce() {
    let hashed = test_event().hash();
    assert_eq!(hashed.get_pow(), 0);
}

// --- Event::get_pow method ---

#[test]
fn signed_event_get_pow_method() {
    let sk = fixed_secret();
    let event = test_event();
    let hashed = mine_pow(&event, 8);
    let sig = sk.sign(&hashed.id);
    let signed = hashed.sign(sig);
    assert!(signed.get_pow() >= 8);
}

// --- OwnedEvent::mine_pow method ---

#[test]
fn owned_event_mine_pow_method() {
    let event = test_event();
    let result = event.mine_pow(8);
    assert!(result.get_pow() >= 8);
}

// --- OwnedEvent::mine_pow_batch method ---

#[test]
fn owned_event_mine_pow_batch_method() {
    let event = test_event();
    let result = event.mine_pow_batch(1, 0, 1_000_000);
    assert!(result.is_some());
    assert!(result.unwrap().get_pow() >= 1);
}

// --- mine_pow (free function) ---

#[test]
fn mine_pow_returns_valid_result() {
    let event = test_event();
    let result = mine_pow(&event, 8);

    assert!(get_leading_zero_bits(&result.id) >= 8);

    let nonce_tag = result.tags.find("nonce").expect("should have nonce tag");
    assert_eq!(nonce_tag.get(2), Some("8"));

    let _nonce: u64 = nonce_tag.value().parse().expect("nonce should be a number");
}

#[test]
fn mine_pow_preserves_event_fields() {
    let event = test_event();
    let result = mine_pow(&event, 4);

    assert_eq!(result.content, event.content);
    assert_eq!(result.kind, event.kind);
    assert_eq!(result.created_at, event.created_at);
    assert_eq!(result.pubkey, event.pubkey);
}

#[test]
fn mine_pow_preserves_existing_tags() {
    let mut event = test_event();
    event.tags.0.push(Tag::new("t", ["nostr"]));
    let result = mine_pow(&event, 4);

    assert!(result.tags.find("t").is_some());
    assert!(result.tags.find("nonce").is_some());
}

#[test]
fn mine_pow_does_not_mutate_input() {
    let event = test_event();
    let tags_before = event.tags.clone();
    let _result = mine_pow(&event, 4);
    assert_eq!(event.tags, tags_before);
}

// --- mine_pow_batch (free function) ---

#[test]
fn mine_pow_batch_returns_none_when_exhausted() {
    let event = test_event();
    let result = mine_pow_batch(&event, 64, 0, 10);
    assert!(result.is_none());
}

#[test]
fn mine_pow_batch_finds_solution_in_range() {
    let event = test_event();
    let result = mine_pow_batch(&event, 1, 0, 1_000_000);
    assert!(result.is_some());
    assert!(get_leading_zero_bits(&result.unwrap().id) >= 1);
}

#[test]
fn mine_pow_batch_respects_start_offset() {
    let event = test_event();
    let a = mine_pow_batch(&event, 4, 0, 1_000_000);
    let b = mine_pow_batch(&event, 4, 500_000, 1_000_000);

    assert!(a.is_some());
    assert!(b.is_some());

    let nonce_a = a.unwrap().tags.find("nonce").unwrap().value().to_string();
    let nonce_b = b.unwrap().tags.find("nonce").unwrap().value().to_string();
    assert_ne!(nonce_a, nonce_b);
}

// --- Integration: mine then sign then verify ---

#[test]
fn mined_event_can_be_signed_and_verified() {
    let sk = fixed_secret();
    let event = test_event();
    let hashed = mine_pow(&event, 8);

    let sig = sk.sign(&hashed.id);
    let signed = hashed.sign(sig);

    assert!(signed.verify_id());
    signed.verify().expect("mined and signed event should verify");
    assert!(signed.get_pow() >= 8);
}