//! Deterministic test-vector generation (kestrove-spec/vectors). Shared by `examples/gen-vectors.rs`
//! and `tests/vectors.rs`. Every input is fixed, so regenerating must reproduce the files byte for byte.
//!
//! Byte strings are lowercase hex unless noted. Envelopes are given in their JSON wire form (base64url).

#![allow(dead_code)] // each includer uses a different subset

use kv_crypto::{
    aad::{Aad, ObjectType},
    aead::{pad, SymKey},
    kdf,
    seal::{seal_to_with_rng, EncKeypair},
    secret_key::SecretKey,
};
use kv_model::{matching, totp::Totp};
use kv_proto::KdfParams;
use serde_json::{json, Value};
use uuid::Uuid;

pub const FILES: [&str; 6] = ["kdf", "envelope", "hpke", "secret_key_format", "totp", "matching"];

pub fn hex(b: &[u8]) -> String {
    b.iter().map(|x| format!("{x:02x}")).collect()
}

pub fn unhex(s: &str) -> Vec<u8> {
    (0..s.len()).step_by(2).map(|i| u8::from_str_radix(&s[i..i + 2], 16).unwrap()).collect()
}

fn id(n: u8) -> Uuid {
    // Valid v4 layout so every implementation's UUID parser accepts it.
    let mut b = [n; 16];
    b[6] = 0x40 | (n & 0x0f);
    b[8] = 0x80 | (n & 0x3f);
    Uuid::from_bytes(b)
}

/// Returns `(file stem, JSON document)` for every vector file.
pub fn generate() -> Vec<(&'static str, Value)> {
    vec![
        ("kdf", kdf_vectors()),
        ("envelope", envelope_vectors()),
        ("hpke", hpke_vectors()),
        ("secret_key_format", secret_key_vectors()),
        ("totp", totp_vectors()),
        ("matching", matching_vectors()),
    ]
}

pub fn render(doc: &Value) -> String {
    let mut s = serde_json::to_string_pretty(doc).unwrap();
    s.push('\n');
    s
}

fn kdf_vectors() -> Value {
    let cases = [
        ("correct horse battery staple", [0x01u8; 16], [0xa5u8; 16], id(0x11)),
        // Leading/trailing whitespace is trimmed and the password NFKD-normalized ("é" precomposed, "fi" ligature).
        ("  caf\u{e9} \u{fb01}sh  ", [0xffu8; 16], [0x00u8; 16], id(0x22)),
    ];
    let vectors: Vec<Value> = cases
        .iter()
        .map(|(pw, sk, salt, account)| {
            let params = KdfParams { alg: "argon2id".into(), m_kib: 64 * 1024, t: 3, p: 4, salt: salt.to_vec() };
            let secret_key = SecretKey::from_bytes(*sk);
            let d = kdf::derive_keys(pw, &secret_key, *account, &params).unwrap();
            json!({
                "password": pw,
                "secret_key": hex(sk),
                "secret_key_display": secret_key.to_display().as_str(),
                "account_id": account.to_string(),
                "params": {"alg": "argon2id", "m_kib": params.m_kib, "t": params.t, "p": params.p, "salt": hex(salt)},
                "root": hex(d.root.as_ref()),
                "auk": hex(d.auk.as_ref()),
                "auth_input": hex(d.auth_input.as_ref()),
            })
        })
        .collect();
    json!({
        "description": "2SKD (docs/02 'Derivation'): Argon2id(NFKD(trim(password))) + HKDF(secret_key) -> root -> AUK, AUTH_INPUT",
        "vectors": vectors,
    })
}

fn envelope_vectors() -> Value {
    let account = id(0x01);
    let vault = id(0x02);
    let item = id(0x03);
    let key = SymKey::from_bytes(id(0x04), [0x42; 32]);
    let item_json = br#"{"id":"03030303-0303-4303-8303-030303030303","kind":"login","title":"Example","created_at":1,"modified_at":1,"seq":1}"#;
    type Case = (&'static str, ObjectType, Option<Uuid>, Option<Uuid>, Vec<u8>, [u8; 24]);
    let cases: Vec<Case> = vec![
        ("item payload (padded)", ObjectType::Item, Some(vault), Some(item), pad(item_json).to_vec(), [0x01; 24]),
        (
            "item key: kid || key",
            ObjectType::ItemKey,
            Some(vault),
            Some(item),
            [id(0x05).as_bytes().as_slice(), &[0x55; 32]].concat(),
            [0x02; 24],
        ),
        ("vault metadata", ObjectType::VaultMeta, Some(vault), None, br#"{"name":"Personal"}"#.to_vec(), [0x03; 24]),
        ("keyset (80 bytes)", ObjectType::Keyset, None, None, (0u8..80).collect(), [0x04; 24]),
    ];
    let vectors: Vec<Value> = cases
        .into_iter()
        .map(|(name, ty, v, i, pt, nonce)| {
            let aad = Aad::build(ty, account, v, i);
            let env = key.seal_with_nonce(nonce, &pt, &aad).unwrap();
            json!({
                "name": name,
                "key": hex(key.expose()),
                "kid": key.id.to_string(),
                "nonce": hex(&nonce),
                "aad": hex(&aad),
                "plaintext": hex(&pt),
                "ciphertext": hex(&env.ct),
                "envelope": env,
            })
        })
        .collect();
    json!({
        "description": "XChaCha20-Poly1305 envelopes with location-binding AAD and 256-byte padding (docs/02 'Envelope format')",
        "aad_layout": "\"kestrove/v1/\" || type || 0x00 || account || 0x00 || vault || 0x00 || item (absent ids = nil UUID)",
        "account_id": account.to_string(),
        "vault_id": vault.to_string(),
        "item_id": item.to_string(),
        "vectors": vectors,
    })
}

/// Yields fixed bytes: the HPKE ephemeral `ikmE`.
struct FixedRng(Vec<u8>, usize);

impl rand_core::RngCore for FixedRng {
    fn next_u32(&mut self) -> u32 {
        let mut b = [0u8; 4];
        self.fill_bytes(&mut b);
        u32::from_le_bytes(b)
    }
    fn next_u64(&mut self) -> u64 {
        let mut b = [0u8; 8];
        self.fill_bytes(&mut b);
        u64::from_le_bytes(b)
    }
    fn fill_bytes(&mut self, dest: &mut [u8]) {
        for d in dest {
            *d = self.0[self.1 % self.0.len()];
            self.1 += 1;
        }
    }
    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand_core::Error> {
        self.fill_bytes(dest);
        Ok(())
    }
}

impl rand_core::CryptoRng for FixedRng {}

fn hpke_vectors() -> Value {
    let account = id(0x01);
    let cases = [([0x11u8; 32], [0x77u8; 32], id(0x02)), ([0x2au8; 32], [0x03u8; 32], id(0x09))];
    let vectors: Vec<Value> = cases
        .iter()
        .map(|(sk, ikm_e, vault)| {
            let kp = EncKeypair::from_secret_bytes(id(0x0e), sk).unwrap();
            let aad = Aad::build(ObjectType::VaultKey, account, Some(*vault), None);
            let pt = [id(0x0a).as_bytes().as_slice(), &[0xab; 32]].concat();
            let env = seal_to_with_rng(kp.id, &kp.public_bytes(), &pt, &aad, &mut FixedRng(ikm_e.to_vec(), 0)).unwrap();
            json!({
                "recipient_sk": hex(sk),
                "recipient_pk": hex(&kp.public_bytes()),
                "recipient_kid": kp.id.to_string(),
                "ikm_e": hex(ikm_e),
                "info": hex(b"kestrove/v1/hpke"),
                "vault_id": vault.to_string(),
                "aad": hex(&aad),
                "plaintext": hex(&pt),
                "enc": hex(&env.enc),
                "ciphertext": hex(&env.ct),
                "envelope": env,
            })
        })
        .collect();
    json!({
        "description": "HPKE base mode, DHKEM(X25519, HKDF-SHA256), HKDF-SHA256, ChaCha20-Poly1305 sealing a vault key (vault key id || key) to the account. ikm_e is the RFC 9180 DeriveKeyPair input for the ephemeral key.",
        "account_id": account.to_string(),
        "vectors": vectors,
    })
}

fn secret_key_vectors() -> Value {
    let raws: [[u8; 16]; 5] = [
        [0x00; 16],
        [0xff; 16],
        [0x80; 16],
        [0xab; 16],
        *b"\x01\x23\x45\x67\x89\xab\xcd\xef\xfe\xdc\xba\x98\x76\x54\x32\x10",
    ];
    let valid: Vec<Value> = raws
        .iter()
        .map(|r| json!({"raw": hex(r), "display": SecretKey::from_bytes(*r).to_display().as_str()}))
        .collect();
    let base = SecretKey::from_bytes(raws[4]).to_display().to_string();
    let lower = base.to_lowercase();
    let spaced = base.replace('-', " ");
    let compact = base.replace('-', "");
    // Crockford confusables: 0 may be typed as O, 1 as I or L.
    let confusable = format!("K1{}", base[2..].replace('0', "O").replace('1', "I"));
    let alternate: Vec<Value> = [lower, spaced, compact, confusable]
        .into_iter()
        .map(|s| {
            assert_eq!(SecretKey::parse(&s).unwrap().expose(), &raws[4], "{s}");
            json!({"input": s, "raw": hex(&raws[4])})
        })
        .collect();

    let check = base.chars().last().unwrap();
    let other_check = if check == '0' { '1' } else { '0' };
    let mut bad_checksum = base.clone();
    bad_checksum.pop();
    bad_checksum.push(other_check);
    let max = SecretKey::from_bytes([0xff; 16]).to_display().to_string();
    let invalid: Vec<Value> = [
        (bad_checksum, "checksum"),
        (base.replacen("K1", "K2", 1), "prefix"),
        (base[..base.len() - 2].to_string(), "length"),
        (max.replacen("K1-7", "K1-8", 1), "overflow: first symbol carries only 3 bits"),
        (base.replacen('-', "-U", 1)[..base.len()].to_string(), "invalid symbol U"),
    ]
    .into_iter()
    .map(|(s, why)| {
        assert!(SecretKey::parse(&s).is_err(), "{s} should be invalid ({why})");
        json!({"input": s, "reason": why})
    })
    .collect();
    json!({
        "description": "Secret Key display format K1-XXXXXX-XXXXX-XXXXX-XXXXX-XXXXX-C: 26 Crockford base32 symbols of the 128-bit key (MSB first, 2 zero pad bits at the top), check symbol = SHA-256(raw)[0] mod 32",
        "alphabet": "0123456789ABCDEFGHJKMNPQRSTVWXYZ",
        "valid": valid,
        "alternate_inputs": alternate,
        "invalid": invalid,
    })
}

fn totp_vectors() -> Value {
    let b32 = |s: &[u8]| data_encoding::BASE32_NOPAD.encode(s);
    let seeds: [(&str, &[u8]); 3] = [
        ("SHA1", b"12345678901234567890"),
        ("SHA256", b"12345678901234567890123456789012"),
        ("SHA512", b"1234567890123456789012345678901234567890123456789012345678901234"),
    ];
    let mut vectors = Vec::new();
    for t in [59u64, 1_111_111_109, 1_111_111_111, 1_234_567_890, 2_000_000_000, 20_000_000_000] {
        for (alg, seed) in seeds {
            let uri = format!("otpauth://totp/RFC6238?secret={}&algorithm={alg}&digits=8&period=30", b32(seed));
            let code = Totp::parse(&uri).unwrap().code_at(t);
            vectors.push(json!({"source": "RFC 6238 Appendix B", "uri": uri, "time": t, "code": code}));
        }
    }
    let defaults = b32(b"12345678901234567890");
    for t in [59u64, 1_111_111_109] {
        vectors.push(json!({"source": "bare base32 secret, defaults (SHA1, 6 digits, 30 s)", "uri": defaults, "time": t, "code": Totp::parse(&defaults).unwrap().code_at(t)}));
    }
    let custom = format!(
        "otpauth://totp/x?secret={}&digits=6&period=60&algorithm=SHA256",
        b32(b"12345678901234567890123456789012")
    );
    vectors.push(json!({"source": "60 s period", "uri": custom, "time": 1_111_111_109u64, "code": Totp::parse(&custom).unwrap().code_at(1_111_111_109)}));
    json!({"description": "RFC 6238 TOTP (HMAC-SHA1/256/512). `uri` is what Totp::parse accepts.", "vectors": vectors})
}

fn matching_vectors() -> Value {
    let cases = [
        ("https://example.com", "https://example.com/login"),
        ("example.com", "https://example.com/"),
        ("https://example.com:8443", "https://example.com"),
        ("https://example.com", "https://login.example.com"),
        ("https://login.example.com", "https://example.com"),
        ("https://a.github.io", "https://b.github.io"),
        ("https://example.com", "https://example.com.evil.net"),
        ("https://example.com", "http://example.com"),
        ("http://example.com", "https://example.com"),
        ("https://example.co.uk", "https://other.co.uk"),
        ("https://shop.example.co.uk", "https://www.example.co.uk/cart"),
        ("https://EXAMPLE.com", "https://example.COM/"),
        ("https://192.168.1.10:8080", "https://192.168.1.10:8080/admin"),
        ("not a url", "https://example.com"),
        ("ftp://example.com", "https://example.com"),
    ];
    let vectors: Vec<Value> = cases
        .iter()
        .map(|(item, page)| {
            let level = match matching::match_url(item, page) {
                matching::MatchLevel::None => "none",
                matching::MatchLevel::Domain => "domain",
                matching::MatchLevel::Host => "host",
                matching::MatchLevel::Exact => "exact",
            };
            json!({"item_url": item, "page_url": page, "level": level})
        })
        .collect();
    json!({"description": "Autofill URL matching (docs/05): exact > host > domain (eTLD+1 via the PSL) > none. http items may match https pages, never the reverse.", "vectors": vectors})
}