//! `EncodedAuthCert`

use std::str::FromStr;

use tor_error::Bug;

use crate::encode::{NetdocEncodable, NetdocEncoder};

use crate::parse2::{

    ErrorProblem, IsStructural, ItemStream, KeywordRef, NetdocParseable, ParseInput,

};

use ErrorProblem as EP;

use crate::doc::netstatus::vote::NetworkStatusUnverifiedParsedBody as NetworkStatusVoteUnverifiedParsedBody;

/// Entire authority key certificate, encoded and signed

///

/// This is a newtype around `String`.

///

/// # Invariants

///

///  * Is a complete document in netdoc metasyntax including trailing newline.

///  * Starts with one `dir-key-certificate-version`

///  * Ends with one `dir-key-certification`

///  * No other items are structural in a vote

///  * Every item keyword starts `dir-` or is `fingerprint`

///

/// See

/// <https://spec.torproject.org/dir-spec/creating-key-certificates.html#nesting>

///

/// ## Non-invariant

///

///  * **Signature and timeliness have not been checked**.

///

/// # Functionality

///

/// Implements `TryFrom<String>` and `FromStr`.

///

/// Implements `NetdocParseable`:

/// parser matches `dir-key-certificate-version` and `dir-key-certification`,

/// but also calls `Bug` if the caller's `stop_at`

/// reports that this keyword is structural for its container.

/// (This could happen if an `EncodedAuthCert` existedd in some other

/// document but a vote.  We do not check this property during encoding.)

///

/// # Rationale

///

/// Unlike most sub-documents found within netdocs, an authcert is a

/// signed document.  We expect to be able to copy an authcert into a

/// vote, encode, convey and parse the vote, and extract the

/// authcert, and verify the authcert's signature.

///

/// Additionally, the fact that authcerts have their own signatures means

/// that they need to be constructed separately from the surrounding

/// document, and then embedded in it later.

///

/// When parsing a vote, we need to be able to see *which parts* are

/// the authcert, and we need to be able to extract the specific document

/// text, but we maybe don't want to parse the authcert.

///

/// Conversely, signature verification of authcerts during decoding of a

/// vote is fairly complex.  We don't want to do signature

/// verification during parsing, because signature verification involves

/// the time, and we don't want parsing to need to know the time.

///

// ## Generics (possible future expansion)

//

// If we discover other similar document nestings we could genericise things:

//

// ```

// /// Invariant:

// ///

// ///  * Can be lexed as a netdoc

// ///  * First item is `Y:is_intro_item_keyword`

// ///  * Last item is (one) `YS:is_intro_item_keyword`

// ///  * No other item is any `N::is_structual_item_keyword`

// ///

// pub struct EncodedNetdoc<Y, YS, (N0, N1 ..)>(String);

//

// pub type EncodedAuthCert = EncodedNetdoc<

//     AuthCert, AuthCertSignatures,

//     (NetworkStatusVote, NetworkStatusSignaturesVote)

// >;

// ```

//

// Details TBD.

//

#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, derive_more::AsRef)]

pub struct EncodedAuthCert(#[as_ref(str)] String);

/// State (machine) for checking item sequence

#[derive(Copy, Clone, Debug, Eq, PartialEq)]

enum ItemSequenceChecker {

    /// Expecting intro item

    Intro,

    /// Expecting body item

    Body,

    /// Expecting no more items

    End,

}

/// Token indicating keyword is structural for us

struct IsOurStructural;

/// auth cert's intro item

const INTRO_KEYWORD: &str = "dir-key-certificate-version";

/// auth cert's final item, used for bracketing

const FINAL_KEYWORD: &str = "dir-key-certification";

impl EncodedAuthCert {

    /// Obtain the document text as a `str`

}

impl ItemSequenceChecker {

    /// Start the state machine

        use ItemSequenceChecker::*;

    /// Process and check an item (given the keyword)

        use ItemSequenceChecker::*;

            } else {

            }

        } else if let Some(IsStructural) =

        {

        } else {

        }

    /// Finish up, on EOF

        use ItemSequenceChecker::*;

        }

}

/// Additional lexical checks

///

/// These might or might not be done by `parse2::lex`.

/// We do them here to be sure.

    // Lexical checks (beyond those done by the lexer)

        // In case our lexer tolerates this

/// Check that `s` meets the constraints

    // Structural checks

    }

impl TryFrom<String> for EncodedAuthCert {

    type Error = ErrorProblem;

}

impl FromStr for EncodedAuthCert {

    type Err = ErrorProblem;

}

impl NetdocParseable for EncodedAuthCert {

                None => {

                }

            }

        }

}

impl NetdocEncodable for EncodedAuthCert {

        // OK because invariants include the right syntax including a trailing newline.

}

#[cfg(test)]

mod test {

    // @@ begin test lint list maintained by maint/add_warning @@

    #![allow(clippy::bool_assert_comparison)]

    #![allow(clippy::clone_on_copy)]

    #![allow(clippy::dbg_macro)]

    #![allow(clippy::mixed_attributes_style)]

    #![allow(clippy::print_stderr)]

    #![allow(clippy::print_stdout)]

    #![allow(clippy::single_char_pattern)]

    #![allow(clippy::unwrap_used)]

    #![allow(clippy::unchecked_time_subtraction)]

    #![allow(clippy::useless_vec)]

    #![allow(clippy::needless_pass_by_value)]

    #![allow(clippy::string_slice)] // See arti#2571

    //! <!-- @@ end test lint list maintained by maint/add_warning @@ -->

    use super::*;

    use crate::parse2::parse_netdoc;

    use derive_deftly::Deftly;

    use std::fmt::{Debug, Display};

    #[derive(Debug, Deftly)]

    #[derive_deftly(NetdocParseable)]

    #[allow(unused)]

    struct Embeds {

        e_intro: (),

        #[deftly(netdoc(subdoc))]

        cert: EncodedAuthCert,

        #[deftly(netdoc(subdoc))]

        subdocs: Vec<Subdoc>,

    }

    #[derive(Debug, Deftly)]

    #[derive_deftly(NetdocParseable)]

    #[allow(unused)]

    struct Subdoc {

        dir_e_subdoc: (),

    }

    fn chk(exp_sole: Result<(), &str>, exp_embed: Result<(), &str>, doc: &str) {

        fn chk1<T: Debug, E: Debug + tor_error::ErrorReport + Display>(

            exp: Result<(), &str>,

            doc: &str,

            what: &str,

            got: Result<T, E>,

        ) {

            eprintln!("==========\n---- {what} 8<- ----\n{doc}---- ->8 {what} ----\n");

            match got {

                Err(got_e) => {

                    let got_m = got_e.report().to_string();

                    eprintln!("{what}, got error: {got_e:?}");

                    eprintln!("{what}, got error: {got_m:?}");

                    let exp_m = exp.expect_err("expected success!");

                    assert!(

                        got_m.contains(exp_m),

                        "{what}, expected different error: {exp_m:?}"

                    );

                }

                y @ Ok(_) => {

                    eprintln!("got {y:?}");

                    assert!(exp.is_ok(), "{what}, unexpected success; expected: {exp:?}");

                }

            }

        }

        chk1(exp_sole, doc, "from_str", EncodedAuthCert::from_str(doc));

        chk1(

            exp_sole,

            doc,

            "From<String>",

            EncodedAuthCert::try_from(doc.to_owned()),

        );

        let embeds = format!(

            r"e-intro

ignored

{doc}dir-e-subdoc

dir-ignored-2

"

        );

        let parse_input = ParseInput::new(&embeds, "<embeds>");

        chk1(

            exp_embed,

            &embeds,

            "embedded",

            parse_netdoc::<Embeds>(&parse_input),

        );

    }

    #[test]

    fn bad_authcerts() {

        NetworkStatusVoteUnverifiedParsedBody::is_structural_keyword(

            KeywordRef::new("dir-source").unwrap(),

        )

        .expect("structural dir-source");

        // These documents are all very skeleton: none of the items have arguments, or objects.

        // It works anyway because we don't actually parse as an authcert, when reading an

        // EncodedAuthCert.  We just check the item keyword sequence.

        chk(

            Err("missing final newline"),

            Err("missing item encoded authority key certificate"),

            r"",

        );

        chk(

            Err("authcert loose body item or missing intro keyword"),

            Err("missing item encoded authority key certificate"),

            r"wrong-intro

",

        );

        chk(

            Err("missing final newline"),

            Err("missing item dir-key-certification"),

            r"dir-key-certificate-version

dir-missing-nl",

        );

        chk(

            Err("authcert bad structure"),

            Err("authcert bad structure"),

            r"dir-key-certificate-version

dir-key-certificate-version

",

        );

        chk(

            Err("authcert body keyword not dir- or fingerprint"),

            Err("authcert body keyword not dir- or fingerprint"),

            r"dir-key-certificate-version

wrong-item

dir-key-certification

",

        );

        chk(

            Err("authcert with vote structural keyword"),

            Err("authcert with vote structural keyword"),

            r"dir-key-certificate-version

r

dir-key-certification

",

        );

        chk(

            Err("authcert with vote structural keyword"),

            Err("authcert with vote structural keyword"),

            r"dir-key-certificate-version

dir-source

dir-key-certification

",

        );

        chk(

            Ok(()), // Simulate bug where EncodedAuthCert doesn't know about our dir-e-subdoc

            Err("bug! parent document structural keyword found"),

            r"dir-key-certificate-version

dir-e-subdoc

dir-key-certification

",

        );

        chk(

            Err("authcert with vote structural keyword"),

            Err("authcert with vote structural keyword"),

            r"dir-key-certificate-version

dir-example-item

r

",

        );

        chk(

            Err("authcert loose body item or missing intro keyword"),

            Err("unexpected loose items after embedded authcert"),

            r"dir-key-certificate-version

dir-example-item

dir-key-certification

dir-extra-item

r

",

        );

        chk(

            Err("authcert bad structure"),

            Err("authcert bad structure"),

            r"dir-key-certificate-version

dir-key-certificate-version

dir-example-item

dir-key-certification

dir-key-certification

r

",

        );

        chk(

            Err("authcert bad structure"),

            Err("unexpected loose items after embedded authcert"),

            r"dir-key-certificate-version

dir-example-item

dir-key-certification

dir-key-certification

r

",

        );

    }

}