//! Computing microdescriptors

use super::*;

/// Error creating a microdescriptor

#[derive(Debug, Clone, thiserror::Error)]

#[non_exhaustive]

pub enum MicrodescError {

    /// Internal error

    #[error("internal error")]

    Internal(#[from] Bug),

}

/// Compute a microdescriptor from a routerdesc

///

/// <https://spec.torproject.org/dir-spec/computing-microdescriptors.html>

        ..MicrodescConstructor {

        }

    };

/// Microdescriptors computed from one routerdesc, for various supported consensus methods

pub type MicrodescsForRouterDesc = BTreeMap<tor_netdoc::doc::netstatus::ConsensusMethods, String>;

/// Errors calculating one or more microdescriptors

pub type MicrodescsErrors = Vec<(SupportedConsensusMethod, MicrodescError)>;

/// Computes the microdescriptor for this descriptor, for each supported consensus method

///

/// If all goes well returns `MicrodescsForRouterDesc`, a map from methods to strings.

/// The map is guaranteed not to have the same *value* for different keys:

/// if different emthods yield the same microdesc, thy will be represented as

/// a single `ConsensusMethods` set mapping to a single `String`.

///

/// Hashing (calculating and collating document digests) is done by the caller of this function.

///

/// If any microdesc couldn't be computed (currently, only possible due to internal errors)

/// returns an `Err` containing both the failed consensus method(s) and the corresponding errors,

/// and the successful results (if any).

///

/// This unusual error handling is so that a handful of strange routerdescs,

/// that trigger bugs in our code, do not cause the whole algorithm to collapse.

/// See torspec!522  TODO DIRAUTH turn this into a proper spec ref when that's merged.

        //

    )

/// "Good" output from [`compute_supported_generic`]

type Outputs<O> = BTreeMap<tor_netdoc::doc::netstatus::ConsensusMethods, O>;

/// Compute `O` for all supported consensus methods

///

/// This is the core of `compute_supported_microdescs`,

/// but made generic so that we can pass an interesting calculation function, for testing.

#[allow(clippy::type_complexity)] // return type is sadly rather complex

            {

            } else {

            };

        })()

    }

    } else {

    }

impl tor_error::HasKind for MicrodescError {

        use MicrodescError as ME;

        use tor_error::ErrorKind as EK;

        }

}

#[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 std::rc::Rc;

    use tor_checkable::TimeBound as _;

    use tor_error::ErrorReport as _;

    use tor_netdoc::{

        assert_eq_or_diff,

        doc::routerdesc::RouterDescUnverified,

        parse2::{NetdocParseableUnverified as _, ParseInput, parse_netdoc},

        test_support::regsub,

        testdata_live,

    };

    fn get_router_desc(relay: &testdata_live::PerRelay) -> anyhow::Result<RouterDesc> {

        let rd_txt = relay.data.plain;

        let rd: RouterDescUnverified = parse_netdoc(&ParseInput::new(rd_txt, relay.nick))?;

        let rd = rd.verify()?.dangerously_assume_timely();

        Ok(rd)

    }

    #[test]

    fn microdescs() -> anyhow::Result<()> {

        let method = TrackedConsensusMethod::new(

            // Test with method 100; will need to bump this occasionally,

            // and/or add more regsub fixups, if this test fails.

            ConsensusMethod(100).try_into()?,

        );

        for relay in testdata_live::RELAY_DESCRIPTORS {

            let rd = get_router_desc(relay)?;

            let md = compute_microdesc(&rd, &method)?;

            let md_txt = encode_netdoc_unsigned([&md])?;

            let mut exp_md = relay.data.md.to_owned();

            regsub(

                &mut exp_md,

                r#"(?x) ^ onion-key \n

                          -----BEGIN\ .*----- \n

                          [^-]+

                          -----END\ .*----- \n

                "#,

                "onion-key\n",

            );

            assert_eq_or_diff!(md_txt, exp_md, "for relay {}", relay.nick);

        }

        Ok(())

    }

    #[test]

    fn all_microdesc() -> anyhow::Result<()> {

        for relay in testdata_live::RELAY_DESCRIPTORS {

            let rd = get_router_desc(relay)?;

            let descs = compute_supported_microdescs(&rd).expect("no bugs");

            for md in descs.values() {

                let _md: Microdesc = parse_netdoc(&ParseInput::new(md, relay.nick))?;

            }

            itertools::assert_equal(

                descs

                    .keys()

                    .flat_map(|m| m.methods.iter())

                    .sorted()

                    .copied(),

                SupportedConsensusMethod::iter_all().map(|m| *m),

            );

        }

        Ok(())

    }

    #[test]

    #[allow(clippy::len_zero)] // assert!(!foo.is_empty()) is just terrible with all the subtle !

    fn buggy_microdesc() -> anyhow::Result<()> {

        // Test error handling of microdescriptor construction.

        // It turns out we can sabotage microdescriptor construction if we bypass

        // RouterDesc::verify, because that fails to populate family info that we need.

        let relay = &testdata_live::RELAY_DESCRIPTORS[0];

        let rd_txt = relay.data.plain;

        let rd: RouterDescUnverified = parse_netdoc(&ParseInput::new(rd_txt, relay.nick))?;

        let rd = rd.unwrap_unverified().0;

        let (errors, descs) = compute_supported_microdescs(&rd)

            .expect_err("should access unverified EmbeddedCert, throwing Bug");

        assert!(descs.len() == 0);

        assert!(errors.len() > 0);

        for (method, error) in errors {

            let _: SupportedConsensusMethod = method;

            let msg = error.report().to_string();

            let exp = "attempted to access verified data of unverified EmbeddedCert";

            assert!(msg.contains(exp), "{msg:?}");

        }

        Ok(())

    }

    #[test]

    fn all_supported_track_coalesce() {

        use crate::consensus::tracked_method::test::interesting_function;

        #[derive(Debug, thiserror::Error)]

        enum TestCaseError {

            #[error("expected")]

            Expected,

            #[error("{0:?}")]

            Internal(#[from] Bug),

        }

        let n_calls = Cell::new(0);

        let (errors, good) = compute_supported_generic(

            (1..=100)

                .map(ConsensusMethod)

                .map(SupportedConsensusMethod::new_unchecked),

            |tracker| {

                n_calls.update(|n_calls| n_calls + 1);

                eprintln!("called with {tracker:?}");

                if tracker == 80 {

                    Err(TestCaseError::Expected)

                } else {

                    let v = interesting_function(tracker);

                    Ok(Rc::new(v))

                }

            },

        )

        .expect_err("80 fails");

        // Check that we got the expected error

        match &*errors {

            [(m, TestCaseError::Expected)] if *m == 80 => {}

            other => panic!("{other:?}"),

        }

        // Check that results are consistent with calculating every value

        for (ms, o) in good {

            for &m in &ms.methods {

                let m = SupportedConsensusMethod::new_unchecked(m);

                let exp = interesting_function(&TrackedConsensusMethod::new(m));

                assert_eq!(*o, exp);

            }

        }

        // Check how many calculations were needed:

        assert_eq!(n_calls.get(), 11);

    }

}