//! `[MC-NBFS]` static dictionary table for `[MC-NBFX]` binary XML.
//!
//! The .NET binary message encoder (`BinaryMessageEncodingBindingElement`,
//! the default for `NetTcpBinding`) compresses common strings — SOAP /
//! WS-Addressing tokens, URIs, frequently-used element/attribute names —
//! by encoding them as a single `Multibyte Int31` index into a
//! globally-known static dictionary. `[MC-NBFS]` §2.2 enumerates that
//! dictionary; the full canonical table has 487 entries, all ASCII.
//!
//! ## Source of truth
//!
//! Every entry below is mirrored from `ServiceModelStringsVersion1` in
//! the .NET WCF source (`dotnet/wcf` repository,
//! `src/System.ServiceModel.Primitives/src/System/ServiceModel/
//! ServiceModelStringsVersion1.cs`), which is the same canonical table
//! that `[MC-NBFS]` §2.2 publishes. The wire dict id is `2 * StringN`
//! where `StringN` is the 0-based position in the WCF source — even
//! ids only; odd ids are reserved for the per-session dynamic dict.
//!
//! ## Coverage
//!
//! Strings 0-200 of the canonical table — id range 0 through 400.
//! Covers the SOAP 1.2 envelope, WS-Addressing 1.0, WS-RM,
//! WS-Security, WS-SecureConversation, WS-Trust, XmlDsig + xenc URIs,
//! and the common SAML / Kerberos / X509 token type URIs. Plus the
//! `xsi` / `xsd` / `nil` / `type` / `i` extras at id 436-444 used
//! heavily by .NET's `XmlSerializer` for value types in custom
//! message-contract bodies.
//!
//! ## Why we don't ship all 487 entries
//!
//! Strings 201-486 cover policy, trust-15, secure-conversation-13, more
//! algorithm URIs, plus the `[MC-NBFC]` Multi-Encoding tokens that the
//! AVEVA wire never references. Adding them is a mechanical extension
//! (port more lines from `ServiceModelStringsVersion1.cs`) but yields
//! no functional improvement against captured wire traffic.
//!
//! ## What the table is NOT
//!
//! ASB-specific contract strings (`"http://ASB.IDataV2"`,
//! `"http://asb.contracts/20111111"`, the operation names, etc.) are
//! **not** in the static dictionary. They live in the per-session
//! *dynamic* dictionary that `[MC-NBFX]` builds up via the
//! binary-message-header pre-pop (odd ids 1, 3, 5, ...). The dynamic
//! dictionary is mutable per session and lives in `crate::nbfx`.

use std::collections::HashMap;
use std::sync::OnceLock;

/// One static-dictionary entry.
#[derive(Debug, Clone, Copy)]
pub struct StaticEntry {
    pub id: u32,
    pub value: &'static str,
}

/// Faithful subset of the `[MC-NBFS]` §2.2 static dictionary, sorted by
/// `id`. Mirrors the first 200 entries of `ServiceModelStringsVersion1`
/// in `dotnet/wcf` (id = `2 * StringN`) plus the 436..444 xsi/xsd/nil
/// extras. Adding more entries is a mechanical extension.
pub const STATIC_ENTRIES: &[StaticEntry] = &[
    StaticEntry { id: 0, value: "mustUnderstand" },
    StaticEntry { id: 2, value: "Envelope" },
    StaticEntry { id: 4, value: "http://www.w3.org/2003/05/soap-envelope" },
    StaticEntry { id: 6, value: "http://www.w3.org/2005/08/addressing" },
    StaticEntry { id: 8, value: "Header" },
    StaticEntry { id: 10, value: "Action" },
    StaticEntry { id: 12, value: "To" },
    StaticEntry { id: 14, value: "Body" },
    StaticEntry { id: 16, value: "Algorithm" },
    StaticEntry { id: 18, value: "RelatesTo" },
    StaticEntry { id: 20, value: "http://www.w3.org/2005/08/addressing/anonymous" },
    StaticEntry { id: 22, value: "URI" },
    StaticEntry { id: 24, value: "Reference" },
    StaticEntry { id: 26, value: "MessageID" },
    StaticEntry { id: 28, value: "Id" },
    StaticEntry { id: 30, value: "Identifier" },
    StaticEntry { id: 32, value: "http://schemas.xmlsoap.org/ws/2005/02/rm" },
    StaticEntry { id: 34, value: "Transforms" },
    StaticEntry { id: 36, value: "Transform" },
    StaticEntry { id: 38, value: "DigestMethod" },
    StaticEntry { id: 40, value: "DigestValue" },
    StaticEntry { id: 42, value: "Address" },
    StaticEntry { id: 44, value: "ReplyTo" },
    StaticEntry { id: 46, value: "SequenceAcknowledgement" },
    StaticEntry { id: 48, value: "AcknowledgementRange" },
    StaticEntry { id: 50, value: "Upper" },
    StaticEntry { id: 52, value: "Lower" },
    StaticEntry { id: 54, value: "BufferRemaining" },
    StaticEntry { id: 56, value: "http://schemas.microsoft.com/ws/2006/05/rm" },
    StaticEntry { id: 58, value: "http://schemas.xmlsoap.org/ws/2005/02/rm/SequenceAcknowledgement" },
    StaticEntry { id: 60, value: "SecurityTokenReference" },
    StaticEntry { id: 62, value: "Sequence" },
    StaticEntry { id: 64, value: "MessageNumber" },
    StaticEntry { id: 66, value: "http://www.w3.org/2000/09/xmldsig#" },
    StaticEntry { id: 68, value: "http://www.w3.org/2000/09/xmldsig#enveloped-signature" },
    StaticEntry { id: 70, value: "KeyInfo" },
    StaticEntry { id: 72, value: "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" },
    StaticEntry { id: 74, value: "http://www.w3.org/2001/04/xmlenc#" },
    StaticEntry { id: 76, value: "http://schemas.xmlsoap.org/ws/2005/02/sc" },
    StaticEntry { id: 78, value: "DerivedKeyToken" },
    StaticEntry { id: 80, value: "Nonce" },
    StaticEntry { id: 82, value: "Signature" },
    StaticEntry { id: 84, value: "SignedInfo" },
    StaticEntry { id: 86, value: "CanonicalizationMethod" },
    StaticEntry { id: 88, value: "SignatureMethod" },
    StaticEntry { id: 90, value: "SignatureValue" },
    StaticEntry { id: 92, value: "DataReference" },
    StaticEntry { id: 94, value: "EncryptedData" },
    StaticEntry { id: 96, value: "EncryptionMethod" },
    StaticEntry { id: 98, value: "CipherData" },
    StaticEntry { id: 100, value: "CipherValue" },
    StaticEntry { id: 102, value: "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" },
    StaticEntry { id: 104, value: "Security" },
    StaticEntry { id: 106, value: "Timestamp" },
    StaticEntry { id: 108, value: "Created" },
    StaticEntry { id: 110, value: "Expires" },
    StaticEntry { id: 112, value: "Length" },
    StaticEntry { id: 114, value: "ReferenceList" },
    StaticEntry { id: 116, value: "ValueType" },
    StaticEntry { id: 118, value: "Type" },
    StaticEntry { id: 120, value: "EncryptedHeader" },
    StaticEntry { id: 122, value: "http://docs.oasis-open.org/wss/oasis-wss-wssecurity-secext-1.1.xsd" },
    StaticEntry { id: 124, value: "RequestSecurityTokenResponseCollection" },
    StaticEntry { id: 126, value: "http://schemas.xmlsoap.org/ws/2005/02/trust" },
    StaticEntry { id: 128, value: "http://schemas.xmlsoap.org/ws/2005/02/trust#BinarySecret" },
    StaticEntry { id: 130, value: "http://schemas.microsoft.com/ws/2006/02/transactions" },
    StaticEntry { id: 132, value: "s" },
    StaticEntry { id: 134, value: "Fault" },
    StaticEntry { id: 136, value: "MustUnderstand" },
    StaticEntry { id: 138, value: "role" },
    StaticEntry { id: 140, value: "relay" },
    StaticEntry { id: 142, value: "Code" },
    StaticEntry { id: 144, value: "Reason" },
    StaticEntry { id: 146, value: "Text" },
    StaticEntry { id: 148, value: "Node" },
    StaticEntry { id: 150, value: "Role" },
    StaticEntry { id: 152, value: "Detail" },
    StaticEntry { id: 154, value: "Value" },
    StaticEntry { id: 156, value: "Subcode" },
    StaticEntry { id: 158, value: "NotUnderstood" },
    StaticEntry { id: 160, value: "qname" },
    StaticEntry { id: 162, value: "" },
    StaticEntry { id: 164, value: "From" },
    StaticEntry { id: 166, value: "FaultTo" },
    StaticEntry { id: 168, value: "EndpointReference" },
    StaticEntry { id: 170, value: "PortType" },
    StaticEntry { id: 172, value: "ServiceName" },
    StaticEntry { id: 174, value: "PortName" },
    StaticEntry { id: 176, value: "ReferenceProperties" },
    StaticEntry { id: 178, value: "RelationshipType" },
    StaticEntry { id: 180, value: "Reply" },
    StaticEntry { id: 182, value: "a" },
    StaticEntry { id: 184, value: "http://schemas.xmlsoap.org/ws/2006/02/addressingidentity" },
    StaticEntry { id: 186, value: "Identity" },
    StaticEntry { id: 188, value: "Spn" },
    StaticEntry { id: 190, value: "Upn" },
    StaticEntry { id: 192, value: "Rsa" },
    StaticEntry { id: 194, value: "Dns" },
    StaticEntry { id: 196, value: "X509v3Certificate" },
    StaticEntry { id: 198, value: "http://www.w3.org/2005/08/addressing/fault" },
    StaticEntry { id: 200, value: "ReferenceParameters" },
    StaticEntry { id: 202, value: "IsReferenceParameter" },
    StaticEntry { id: 204, value: "http://www.w3.org/2005/08/addressing/reply" },
    StaticEntry { id: 206, value: "http://www.w3.org/2005/08/addressing/none" },
    StaticEntry { id: 208, value: "Metadata" },
    StaticEntry { id: 210, value: "http://schemas.xmlsoap.org/ws/2004/08/addressing" },
    StaticEntry { id: 212, value: "http://schemas.xmlsoap.org/ws/2004/08/addressing/role/anonymous" },
    StaticEntry { id: 214, value: "http://schemas.xmlsoap.org/ws/2004/08/addressing/fault" },
    StaticEntry { id: 216, value: "http://schemas.xmlsoap.org/ws/2004/06/addressingex" },
    StaticEntry { id: 218, value: "RedirectTo" },
    StaticEntry { id: 220, value: "Via" },
    StaticEntry { id: 222, value: "http://www.w3.org/2001/10/xml-exc-c14n#" },
    StaticEntry { id: 224, value: "PrefixList" },
    StaticEntry { id: 226, value: "InclusiveNamespaces" },
    StaticEntry { id: 228, value: "ec" },
    StaticEntry { id: 230, value: "SecurityContextToken" },
    StaticEntry { id: 232, value: "Generation" },
    StaticEntry { id: 234, value: "Label" },
    StaticEntry { id: 236, value: "Offset" },
    StaticEntry { id: 238, value: "Properties" },
    StaticEntry { id: 240, value: "Cookie" },
    StaticEntry { id: 242, value: "wsc" },
    StaticEntry { id: 244, value: "http://schemas.xmlsoap.org/ws/2004/04/sc" },
    StaticEntry { id: 246, value: "http://schemas.xmlsoap.org/ws/2004/04/security/sc/dk" },
    StaticEntry { id: 248, value: "http://schemas.xmlsoap.org/ws/2004/04/security/sc/sct" },
    StaticEntry { id: 250, value: "http://schemas.xmlsoap.org/ws/2004/04/security/trust/RST/SCT" },
    StaticEntry { id: 252, value: "http://schemas.xmlsoap.org/ws/2004/04/security/trust/RSTR/SCT" },
    StaticEntry { id: 254, value: "RenewNeeded" },
    StaticEntry { id: 256, value: "BadContextToken" },
    StaticEntry { id: 258, value: "c" },
    StaticEntry { id: 260, value: "http://schemas.xmlsoap.org/ws/2005/02/sc/dk" },
    StaticEntry { id: 262, value: "http://schemas.xmlsoap.org/ws/2005/02/sc/sct" },
    StaticEntry { id: 264, value: "http://schemas.xmlsoap.org/ws/2005/02/trust/RST/SCT" },
    StaticEntry { id: 266, value: "http://schemas.xmlsoap.org/ws/2005/02/trust/RSTR/SCT" },
    StaticEntry { id: 268, value: "http://schemas.xmlsoap.org/ws/2005/02/trust/RST/SCT/Renew" },
    StaticEntry { id: 270, value: "http://schemas.xmlsoap.org/ws/2005/02/trust/RSTR/SCT/Renew" },
    StaticEntry { id: 272, value: "http://schemas.xmlsoap.org/ws/2005/02/trust/RST/SCT/Cancel" },
    StaticEntry { id: 274, value: "http://schemas.xmlsoap.org/ws/2005/02/trust/RSTR/SCT/Cancel" },
    StaticEntry { id: 276, value: "http://www.w3.org/2001/04/xmlenc#aes128-cbc" },
    StaticEntry { id: 278, value: "http://www.w3.org/2001/04/xmlenc#kw-aes128" },
    StaticEntry { id: 280, value: "http://www.w3.org/2001/04/xmlenc#aes192-cbc" },
    StaticEntry { id: 282, value: "http://www.w3.org/2001/04/xmlenc#kw-aes192" },
    StaticEntry { id: 284, value: "http://www.w3.org/2001/04/xmlenc#aes256-cbc" },
    StaticEntry { id: 286, value: "http://www.w3.org/2001/04/xmlenc#kw-aes256" },
    StaticEntry { id: 288, value: "http://www.w3.org/2001/04/xmlenc#des-cbc" },
    StaticEntry { id: 290, value: "http://www.w3.org/2000/09/xmldsig#dsa-sha1" },
    StaticEntry { id: 292, value: "http://www.w3.org/2001/10/xml-exc-c14n#WithComments" },
    StaticEntry { id: 294, value: "http://www.w3.org/2000/09/xmldsig#hmac-sha1" },
    StaticEntry { id: 296, value: "http://www.w3.org/2001/04/xmldsig-more#hmac-sha256" },
    StaticEntry { id: 298, value: "http://schemas.xmlsoap.org/ws/2005/02/sc/dk/p_sha1" },
    StaticEntry { id: 300, value: "http://www.w3.org/2001/04/xmlenc#ripemd160" },
    StaticEntry { id: 302, value: "http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p" },
    StaticEntry { id: 304, value: "http://www.w3.org/2000/09/xmldsig#rsa-sha1" },
    StaticEntry { id: 306, value: "http://www.w3.org/2001/04/xmldsig-more#rsa-sha256" },
    StaticEntry { id: 308, value: "http://www.w3.org/2001/04/xmlenc#rsa-1_5" },
    StaticEntry { id: 310, value: "http://www.w3.org/2000/09/xmldsig#sha1" },
    StaticEntry { id: 312, value: "http://www.w3.org/2001/04/xmlenc#sha256" },
    StaticEntry { id: 314, value: "http://www.w3.org/2001/04/xmlenc#sha512" },
    StaticEntry { id: 316, value: "http://www.w3.org/2001/04/xmlenc#tripledes-cbc" },
    StaticEntry { id: 318, value: "http://www.w3.org/2001/04/xmlenc#kw-tripledes" },
    StaticEntry { id: 320, value: "http://schemas.xmlsoap.org/2005/02/trust/tlsnego#TLS_Wrap" },
    StaticEntry { id: 322, value: "http://schemas.xmlsoap.org/2005/02/trust/spnego#GSS_Wrap" },
    StaticEntry { id: 324, value: "http://schemas.microsoft.com/ws/2006/05/security" },
    StaticEntry { id: 326, value: "dnse" },
    StaticEntry { id: 328, value: "o" },
    StaticEntry { id: 330, value: "Password" },
    StaticEntry { id: 332, value: "PasswordText" },
    StaticEntry { id: 334, value: "Username" },
    StaticEntry { id: 336, value: "UsernameToken" },
    StaticEntry { id: 338, value: "BinarySecurityToken" },
    StaticEntry { id: 340, value: "EncodingType" },
    StaticEntry { id: 342, value: "KeyIdentifier" },
    StaticEntry { id: 344, value: "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary" },
    StaticEntry { id: 346, value: "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#HexBinary" },
    StaticEntry { id: 348, value: "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Text" },
    StaticEntry { id: 350, value: "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X509SubjectKeyIdentifier" },
    StaticEntry { id: 352, value: "http://docs.oasis-open.org/wss/oasis-wss-kerberos-token-profile-1.1#GSS_Kerberosv5_AP_REQ" },
    StaticEntry { id: 354, value: "http://docs.oasis-open.org/wss/oasis-wss-kerberos-token-profile-1.1#GSS_Kerberosv5_AP_REQ1510" },
    StaticEntry { id: 356, value: "http://docs.oasis-open.org/wss/oasis-wss-saml-token-profile-1.0#SAMLAssertionID" },
    StaticEntry { id: 358, value: "Assertion" },
    StaticEntry { id: 360, value: "urn:oasis:names:tc:SAML:1.0:assertion" },
    StaticEntry { id: 362, value: "http://docs.oasis-open.org/wss/oasis-wss-rel-token-profile-1.0.pdf#license" },
    StaticEntry { id: 364, value: "FailedAuthentication" },
    StaticEntry { id: 366, value: "InvalidSecurityToken" },
    StaticEntry { id: 368, value: "InvalidSecurity" },
    StaticEntry { id: 370, value: "k" },
    StaticEntry { id: 372, value: "SignatureConfirmation" },
    StaticEntry { id: 374, value: "TokenType" },
    StaticEntry { id: 376, value: "http://docs.oasis-open.org/wss/oasis-wss-soap-message-security-1.1#ThumbprintSHA1" },
    StaticEntry { id: 378, value: "http://docs.oasis-open.org/wss/oasis-wss-soap-message-security-1.1#EncryptedKey" },
    StaticEntry { id: 380, value: "http://docs.oasis-open.org/wss/oasis-wss-soap-message-security-1.1#EncryptedKeySHA1" },
    StaticEntry { id: 382, value: "http://docs.oasis-open.org/wss/oasis-wss-saml-token-profile-1.1#SAMLV1.1" },
    StaticEntry { id: 384, value: "http://docs.oasis-open.org/wss/oasis-wss-saml-token-profile-1.1#SAMLV2.0" },
    StaticEntry { id: 386, value: "http://docs.oasis-open.org/wss/oasis-wss-saml-token-profile-1.1#SAMLID" },
    StaticEntry { id: 388, value: "AUTH-HASH" },
    StaticEntry { id: 390, value: "RequestSecurityTokenResponse" },
    StaticEntry { id: 392, value: "KeySize" },
    StaticEntry { id: 394, value: "RequestedTokenReference" },
    StaticEntry { id: 396, value: "AppliesTo" },
    StaticEntry { id: 398, value: "Authenticator" },
    StaticEntry { id: 400, value: "CombinedHash" },
    // ---- xsi / xsd / nil — heavily used by .NET XmlSerializer for
    // value types in custom message-contract bodies. These are
    // String 218..222 in the canonical table.
    StaticEntry { id: 436, value: "type" },
    StaticEntry { id: 438, value: "i" },
    StaticEntry { id: 440, value: "http://www.w3.org/2001/XMLSchema-instance" },
    StaticEntry { id: 442, value: "http://www.w3.org/2001/XMLSchema" },
    StaticEntry { id: 444, value: "nil" },
];

/// Lookup an entry by static-dictionary ID. Returns `None` for IDs
/// outside the curated subset; callers should treat that as "unknown
/// static ID" and either extend [`STATIC_ENTRIES`] or fall through to
/// the inline-string path.
pub fn lookup_static(id: u32) -> Option<&'static str> {
    STATIC_ENTRIES
        .binary_search_by_key(&id, |e| e.id)
        .ok()
        .and_then(|idx| STATIC_ENTRIES.get(idx).map(|e| e.value))
}

/// Reverse lookup — find the static-dictionary ID for a string. Returns
/// `None` for strings not in the curated subset; encoders can either
/// extend [`STATIC_ENTRIES`] or fall through to the inline-string /
/// dynamic-dictionary path.
pub fn position_of_static(value: &str) -> Option<u32> {
    static REVERSE: OnceLock<HashMap<&'static str, u32>> = OnceLock::new();
    let map = REVERSE.get_or_init(|| {
        let mut map = HashMap::with_capacity(STATIC_ENTRIES.len());
        for entry in STATIC_ENTRIES {
            // First-id-wins for duplicates (the canonical dictionary
            // has TokenType at both id 116 (String 58) and id 374
            // (String 187); we lock the lower id so round-trip lookups
            // are deterministic).
            map.entry(entry.value).or_insert(entry.id);
        }
        map
    });
    map.get(value).copied()
}

#[cfg(test)]
#[allow(
    clippy::unwrap_used,
    clippy::expect_used,
    clippy::panic,
    clippy::indexing_slicing
)]
mod tests {
    use super::*;

    #[test]
    fn static_entries_have_monotonic_ids() {
        let mut last = None;
        for entry in STATIC_ENTRIES {
            if let Some(prev) = last {
                assert!(
                    entry.id > prev,
                    "static dictionary entries must be sorted by id; saw {prev} then {}",
                    entry.id
                );
            }
            last = Some(entry.id);
        }
    }

    #[test]
    fn static_entries_use_even_ids() {
        // `[MC-NBFS]` reserves odd ids for the per-session dynamic dict
        // (`[MC-NBFX]` records 0xAA / 0xAB DictionaryText use the parity
        // bit to discriminate). All static-table ids must be even.
        for entry in STATIC_ENTRIES {
            assert_eq!(
                entry.id % 2,
                0,
                "static entry id {} ('{}') is odd — odd ids are reserved for the dynamic dict",
                entry.id,
                entry.value
            );
        }
    }

    #[test]
    fn lookup_returns_known_entries() {
        assert_eq!(lookup_static(0), Some("mustUnderstand"));
        assert_eq!(lookup_static(2), Some("Envelope"));
        assert_eq!(
            lookup_static(4),
            Some("http://www.w3.org/2003/05/soap-envelope")
        );
        assert_eq!(lookup_static(8), Some("Header"));
        assert_eq!(lookup_static(14), Some("Body"));
    }

    /// Fault-subset round-trip: every entry the SOAP-1.2 fault body
    /// references must resolve. These are the exact dict ids the
    /// AVEVA MxDataProvider sends in `dispatcher/fault` envelopes
    /// (verified live via `MX_ASB_TRACE_REPLY`). Earlier versions of
    /// this table mis-numbered the SOAP-fault subset (Fault was at id
    /// 114 instead of 134), causing `decode_envelope` to silently drop
    /// the resolved field name and the consumer to see opaque
    /// `Static(N)` tokens.
    #[test]
    fn fault_subset_resolves_to_canonical_strings() {
        assert_eq!(lookup_static(132), Some("s"));
        assert_eq!(lookup_static(134), Some("Fault"));
        assert_eq!(lookup_static(136), Some("MustUnderstand"));
        assert_eq!(lookup_static(142), Some("Code"));
        assert_eq!(lookup_static(144), Some("Reason"));
        assert_eq!(lookup_static(146), Some("Text"));
        assert_eq!(lookup_static(148), Some("Node"));
        assert_eq!(lookup_static(150), Some("Role"));
        assert_eq!(lookup_static(152), Some("Detail"));
        assert_eq!(lookup_static(154), Some("Value"));
        assert_eq!(lookup_static(156), Some("Subcode"));
    }

    #[test]
    fn xmlserializer_extras_resolve() {
        // The 436..444 high-id extras are essential for any
        // [MessageContract] response body that uses XmlSerializer.
        assert_eq!(lookup_static(436), Some("type"));
        assert_eq!(lookup_static(438), Some("i"));
        assert_eq!(
            lookup_static(440),
            Some("http://www.w3.org/2001/XMLSchema-instance")
        );
        assert_eq!(
            lookup_static(442),
            Some("http://www.w3.org/2001/XMLSchema")
        );
        assert_eq!(lookup_static(444), Some("nil"));
    }

    #[test]
    fn position_of_static_round_trips_known_strings() {
        assert_eq!(position_of_static("mustUnderstand"), Some(0));
        assert_eq!(position_of_static("Envelope"), Some(2));
        assert_eq!(position_of_static("Fault"), Some(134));
        assert_eq!(position_of_static("Reason"), Some(144));
    }

    #[test]
    fn lookup_returns_none_for_unknown() {
        // 1 is odd → reserved for dynamic dict; should always be None.
        assert_eq!(lookup_static(1), None);
        // Way past the table.
        assert_eq!(lookup_static(9999), None);
    }
}