//! Implements a usable view of Tor network parameters.

//!

//! The Tor consensus document contains a number of 'network

//! parameters', which are integer-valued items voted on by the

//! directory authorities.  They are used to tune the behavior of

//! numerous aspects of the network.

//! A set of Tor network parameters

//!

//! The Tor consensus document contains a number of 'network

//! parameters', which are integer-valued items voted on by the

//! directory authorities.  These parameters are used to tune the

//! behavior of numerous aspects of the network.

//!

//! This type differs from

//! [`NetParams`](tor_netdoc::doc::netstatus::NetParams) in that it

//! only exposes a set of parameters recognized by arti.  In return

//! for this restriction, it makes sure that the values it gives are

//! in range, and provides default values for any parameters that are

//! missing.

use std::convert::TryInto;

use tor_units::{

    BoundedInt32, IntegerDays, IntegerMilliseconds, IntegerSeconds, Percentage, SendMeVersion,

};

/// An object that can be constructed from an i32, with saturating semantics.

pub trait FromInt32Saturating {

    /// Construct an instance of this object from `val`.

    ///

    /// If `val` is too low, treat it as the lowest value that would be

    /// valid.  If `val` is too high, treat it as the highest value that

    /// would be valid.

    fn from_saturating(val: i32) -> Self;

}

impl FromInt32Saturating for i32 {

}

impl<const L: i32, const H: i32> FromInt32Saturating for BoundedInt32<L, H> {

}

impl<T: Copy + Into<f64> + FromInt32Saturating> FromInt32Saturating for Percentage<T> {

}

impl<T: FromInt32Saturating + TryInto<u64>> FromInt32Saturating for IntegerMilliseconds<T> {

}

impl<T: FromInt32Saturating + TryInto<u64>> FromInt32Saturating for IntegerSeconds<T> {

}

impl<T: FromInt32Saturating + TryInto<u64>> FromInt32Saturating for IntegerDays<T> {

}

impl FromInt32Saturating for SendMeVersion {

}

/// A macro to help us declare the net parameters object.  It lets us

/// put the information about each parameter in just one place, even

/// though it will later get split between the struct declaration, the

/// Default implementation, and the implementation of

/// `saturating_update_override`.

macro_rules! declare_net_parameters {

    {

        $(#[$s_meta:meta])* $s_v:vis struct $s_name:ident {

            $(

                $(#[$p_meta:meta])* $p_v:vis

                    $p_name:ident : $p_type:ty

                    = ($p_dflt:expr) from $p_string:literal

            ),*

            $( , )?

        }

    } =>

    {

        $(#[$s_meta])* $s_v struct $s_name {

            $(

                $(#[$p_meta])* $p_v $p_name : $p_type

            ),*

        }

        impl $s_name {

            /// Try to construct an instance of with its default values.

            ///

            /// (This should always succeed, unless one of the default values

            /// is out-of-bounds for the type.)

                })

            /// Replace the current value for the parameter identified in the

            /// consensus with `key` with a new value `val`.

            ///

            /// Uses saturating semantics if the new value is out-of-range.

            ///

            /// Returns true if the key was recognized, and false otherwise.

                }

        }

    }

}

declare_net_parameters! {

/// This structure holds recognized configuration parameters. All values are type-safe,

/// and where applicable clamped to be within range.

#[non_exhaustive]

pub struct NetParameters {

    /// A weighting factor for bandwidth calculations

    pub bw_weight_scale: BoundedInt32<1, { i32::MAX }> = (10_000)

        from "bwweightscale",

    /// If true, do not attempt to learn circuit-build timeouts at all.

    pub cbt_learning_disabled: BoundedInt32<0, 1> = (0)

        from "cbtdisabled",

    /// Number of histograms bins to consider when estimating Xm for a

    /// Pareto-based circuit timeout estimator.

    pub cbt_num_xm_modes: BoundedInt32<1, 20> = (10)

        from "cbtnummodes",

    /// How many recent circuit success/timeout statuses do we remember

    /// when trying to tell if our circuit timeouts are too low?

    pub cbt_success_count: BoundedInt32<3, 1_000> = (20)

        from "cbtrecentcount",

    /// How many timeouts (in the last `cbt_success_count` observations)

    /// indicates that our circuit timeouts are too low?

    pub cbt_max_timeouts: BoundedInt32<3, 10_000> = (18)

        from "cbtmaxtimeouts",

    /// Smallest number of circuit build times we have to view in order to use

    /// our Pareto-based circuit timeout estimator.

    pub cbt_min_circs_for_estimate: BoundedInt32<1, 10_000> = (100)

        from "cbtmincircs",

    /// Quantile to use when determining the correct circuit timeout value

    /// with our Pareto estimator.

    ///

    /// (We continue building circuits after this timeout, but only

    /// for build-time measurement purposes.)

    pub cbt_timeout_quantile: Percentage<BoundedInt32<10, 99>> = (80)

        from "cbtquantile",

    /// Quantile to use when determining when to abandon circuits completely

    /// with our Pareto estimator.

    pub cbt_abandon_quantile: Percentage<BoundedInt32<10, 99>> = (99)

        from "cbtclosequantile",

    /// Lowest permissible timeout value for Pareto timeout estimator.

    pub cbt_min_timeout: IntegerMilliseconds<BoundedInt32<10, { i32::MAX }>> = (10)

        from "cbtmintimeout",

    /// Timeout value to use for our Pareto timeout estimator when we have

    /// no initial estimate.

    pub cbt_initial_timeout: IntegerMilliseconds<BoundedInt32<10, { i32::MAX }>> = (60_000)

        from "cbtinitialtimeout",

    /// When we don't have a good build-time estimate yet, how long

    /// (in seconds) do we wait between trying to launch build-time

    /// testing circuits through the network?

    pub cbt_testing_delay: IntegerSeconds<BoundedInt32<1, { i32::MAX }>> = (10)

        from "cbttestfreq",

    /// How many circuits can be open before we will no longer

    /// consider launching testing circuits to learn average build

    /// times?

    pub cbt_max_open_circuits_for_testing: BoundedInt32<0, 14> = (10)

        from "cbtmaxopencircs",

    /// The maximum cell window size?

    pub circuit_window: BoundedInt32<100, 1000> = (1_000)

        from "circwindow",

    /// The decay parameter for circuit priority

    pub circuit_priority_half_life: IntegerMilliseconds<BoundedInt32<1, { i32::MAX }>> = (30_000)

        from "CircuitPriorityHalflifeMsec",

    /// Whether to perform circuit extensions by Ed25519 ID

    pub extend_by_ed25519_id: BoundedInt32<0, 1> = (0)

        from "ExtendByEd25519ID",

    /// If we have excluded so many possible guards that the

    /// available fraction is below this threshold, we should use a different

    /// guard sample. (TODO: not actually implemented)

    pub guard_meaningful_restriction: Percentage<BoundedInt32<1,100>> = (20)

        from "guard-meaningful-restriction-percent",

    /// We should warn the user if they have excluded so many guards

    /// that the available fraction is below this threshold.

    pub guard_extreme_restriction: Percentage<BoundedInt32<1,100>> = (1)

        from "guard-extreme-restriction-percent",

    /// How long should we keep an unconfirmed guard (one we have not

    /// contacted) before removing it from the guard sample?

    pub guard_lifetime_unconfirmed: IntegerDays<BoundedInt32<1, 3650>> = (120)

        from "guard-lifetime-days",

    /// How long should we keep a _confirmed_ guard (one we have contacted)

    /// before removing it from the guard sample?

    pub guard_lifetime_confirmed: IntegerDays<BoundedInt32<1, 3650>> = (60)

        from "guard-confirmed-min-lifetime-days",

    /// If all circuits have failed for this interval, then treat the internet

    /// as "probably down", and treat any guard failures in that interval

    /// as unproven.

    pub guard_internet_likely_down: IntegerSeconds<BoundedInt32<1, {i32::MAX}>> = (600)

        from "guard-internet-likely-down-interval",

    /// Largest number of guards that a client should try to maintain in

    /// a sample of possible guards.

    pub guard_max_sample_size: BoundedInt32<1, {i32::MAX}> = (60)

        from "guard-max-sample-size",

    /// Largest fraction of guard bandwidth on the network that a client

    /// should try to remain in a sample of possible guards.

    pub guard_max_sample_threshold: Percentage<BoundedInt32<1,100>> = (20)

        from "guard-max-sample-threshold",

    /// If the client ever has fewer than this many guards in their sample,

    /// after filtering out unusable guards, they should try to add more guards

    /// to the sample (if allowed).

    pub guard_filtered_min_sample_size: BoundedInt32<1,{i32::MAX}> = (20)

        from "guard-min-filtered-sample-size",

    /// The number of confirmed guards that the client should treat as

    /// "primary guards".

    pub guard_n_primary: BoundedInt32<1,{i32::MAX}> = (3)

        from "guard-n-primary-guards",

    /// The number of primary guards that the client should use in parallel.

    /// Other primary guards won't get used unless earlier ones are down.

    pub guard_use_parallelism: BoundedInt32<1, {i32::MAX}> = (1)

        from "guard-n-primary-guards-to-use",

    /// The number of primary guards that the client should use in

    /// parallel.  Other primary directory guards won't get used

    /// unless earlier ones are down.

    pub guard_dir_use_parallelism: BoundedInt32<1, {i32::MAX}> = (3)

        from "guard-n-primary-dir-guards-to-use",

    /// When trying to confirm nonprimary guards, if a guard doesn't

    /// answer for more than this long in seconds, treat any lower-

    /// priority guards as possibly usable.

    pub guard_nonprimary_connect_timeout: IntegerSeconds<BoundedInt32<1,{i32::MAX}>> = (15)

        from "guard-nonprimary-guard-connect-timeout",

    /// When trying to confirm nonprimary guards, if a guard doesn't

    /// answer for more than _this_ long in seconds, treat it as down.

    pub guard_nonprimary_idle_timeout: IntegerSeconds<BoundedInt32<1,{i32::MAX}>> = (600)

        from "guard-nonprimary-guard-idle-timeout",

    /// If a guard has been unlisted in the consensus for at least this

    /// long, remove it from the consensus.

    pub guard_remove_unlisted_after: IntegerDays<BoundedInt32<1,3650>> = (20)

        from "guard-remove-unlisted-guards-after-days",

    /// The minimum threshold for circuit patch construction

    pub min_circuit_path_threshold: Percentage<BoundedInt32<25, 95>> = (60)

        from "min_paths_for_circs_pct",

    /// The minimum sendme version to accept.

    pub sendme_accept_min_version: SendMeVersion = (0)

        from "sendme_accept_min_version",

    /// The minimum sendme version to transmit.

    pub sendme_emit_min_version: SendMeVersion = (0)

        from "sendme_emit_min_version",

    /// How long should never-used client circuits stay available,

    /// in the steady state?

    pub unused_client_circ_timeout: IntegerSeconds<BoundedInt32<60, 86_400>> = (30*60)

        from "nf_conntimeout_clients",

    /// When we're learning circuit timeouts, how long should never-used client

    /// circuits stay available?

    pub unused_client_circ_timeout_while_learning_cbt: IntegerSeconds<BoundedInt32<10, 60_000>> = (3*60)

        from "cbtlearntimeout",

}

}

impl Default for NetParameters {

}

impl NetParameters {

    /// Construct a new NetParameters from a given list of key=value parameters.

    ///

    /// Unrecognized parameters are ignored.

    /// Replace a list of parameters, using the logic of

    /// `set_saturating`.

    ///

    /// Return a vector of the parameter names we didn't recognize.

        }

}

#[cfg(test)]

#[allow(clippy::many_single_char_names)]

#[allow(clippy::unwrap_used)]

#[allow(clippy::cognitive_complexity)]

mod test {

    use super::*;

    use std::string::String;

    #[test]

    fn empty_list() {

        let mut x = NetParameters::default();

        let y = Vec::<(&String, &i32)>::new();

        let u = x.saturating_update(y.into_iter());

        assert!(u.is_empty());

    }

    #[test]

    fn unknown_parameter() {

        let mut x = NetParameters::default();

        let mut y = Vec::<(&String, &i32)>::new();

        let k = &String::from("This_is_not_a_real_key");

        let v = &456;

        y.push((k, v));

        let u = x.saturating_update(y.into_iter());

        assert_eq!(u, vec![&String::from("This_is_not_a_real_key")]);

    }

    // #[test]

    // fn duplicate_parameter() {}

    #[test]

    fn single_good_parameter() {

        let mut x = NetParameters::default();

        let mut y = Vec::<(&String, &i32)>::new();

        let k = &String::from("min_paths_for_circs_pct");

        let v = &54;

        y.push((k, v));

        let z = x.saturating_update(y.into_iter());

        assert!(z.is_empty());

        assert_eq!(x.min_circuit_path_threshold.as_percent().get(), 54);

    }

    #[test]

    fn multiple_good_parameters() {

        let mut x = NetParameters::default();

        let mut y = Vec::<(&String, &i32)>::new();

        let k = &String::from("min_paths_for_circs_pct");

        let v = &54;

        y.push((k, v));

        let k = &String::from("circwindow");

        let v = &900;

        y.push((k, v));

        let z = x.saturating_update(y.into_iter());

        assert!(z.is_empty());

        assert_eq!(x.min_circuit_path_threshold.as_percent().get(), 54);

        assert_eq!(x.circuit_window.get(), 900);

    }

    #[test]

    fn good_out_of_range() {

        let mut x = NetParameters::default();

        let mut y = Vec::<(&String, &i32)>::new();

        let k = &String::from("sendme_accept_min_version");

        let v = &30;

        y.push((k, v));

        let k = &String::from("min_paths_for_circs_pct");

        let v = &255;

        y.push((k, v));

        let z = x.saturating_update(y.into_iter());

        assert!(z.is_empty());

        assert_eq!(x.sendme_accept_min_version.get(), 30);

        assert_eq!(x.min_circuit_path_threshold.as_percent().get(), 95);

    }

    #[test]

    fn good_invalid_rep() {

        let mut x = NetParameters::default();

        let mut y = Vec::<(&String, &i32)>::new();

        let k = &String::from("sendme_accept_min_version");

        let v = &30;

        y.push((k, v));

        let k = &String::from("min_paths_for_circs_pct");

        let v = &9000;

        y.push((k, v));

        let z = x.saturating_update(y.into_iter());

        assert!(z.is_empty());

        assert_eq!(x.sendme_accept_min_version.get(), 30);

        assert_eq!(x.min_circuit_path_threshold.as_percent().get(), 95);

    }

    // #[test]

    // fn good_duplicate() {}

    #[test]

    fn good_unknown() {

        let mut x = NetParameters::default();

        let mut y = Vec::<(&String, &i32)>::new();

        let k = &String::from("sendme_accept_min_version");

        let v = &30;

        y.push((k, v));

        let k = &String::from("not_a_real_parameter");

        let v = &9000;

        y.push((k, v));

        let z = x.saturating_update(y.into_iter());

        assert_eq!(z, vec![&String::from("not_a_real_parameter")]);

        assert_eq!(x.sendme_accept_min_version.get(), 30);

    }

    #[test]

    fn from_consensus() {

        let mut p = NetParameters::default();

        let mut mp: std::collections::HashMap<String, i32> = std::collections::HashMap::new();

        mp.insert("bwweightscale".to_string(), 70);

        mp.insert("min_paths_for_circs_pct".to_string(), 45);

        mp.insert("im_a_little_teapot".to_string(), 1);

        mp.insert("circwindow".to_string(), 99999);

        mp.insert("ExtendByEd25519ID".to_string(), 1);

        let z = p.saturating_update(mp.iter());

        assert_eq!(z, vec![&String::from("im_a_little_teapot")]);

        assert_eq!(p.bw_weight_scale.get(), 70);

        assert_eq!(p.min_circuit_path_threshold.as_percent().get(), 45);

        let b_val: bool = p.extend_by_ed25519_id.into();

        assert!(b_val);

    }

    #[test]

    fn all_parameters() {

        use std::convert::TryFrom;

        use std::time::Duration;

        let mut p = NetParameters::default();

        let mp = [

            ("bwweightscale", 10),

            ("cbtdisabled", 1),

            ("cbtnummodes", 11),

            ("cbtrecentcount", 12),

            ("cbtmaxtimeouts", 13),

            ("cbtmincircs", 5),

            ("cbtquantile", 61),

            ("cbtclosequantile", 15),

            ("cbtlearntimeout", 1900),

            ("cbtmintimeout", 2020),

            ("cbtinitialtimeout", 2050),

            ("cbttestfreq", 110),

            ("cbtmaxopencircs", 14),

            ("circwindow", 999),

            ("CircuitPriorityHalflifeMsec", 222),

            ("guard-lifetime-days", 36),

            ("guard-confirmed-min-lifetime-days", 37),

            ("guard-internet-likely-down-interval", 38),

            ("guard-max-sample-size", 39),

            ("guard-max-sample-threshold", 40),

            ("guard-min-filtered-sample-size", 41),

            ("guard-n-primary-guards", 42),

            ("guard-n-primary-guards-to-use", 43),

            ("guard-n-primary-dir-guards-to-use", 44),

            ("guard-nonprimary-guard-connect-timeout", 45),

            ("guard-nonprimary-guard-idle-timeout", 46),

            ("guard-remove-unlisted-guards-after-days", 47),

            ("guard-meaningful-restriction-percent", 12),

            ("guard-extreme-restriction-percent", 3),

            ("ExtendByEd25519ID", 0),

            ("min_paths_for_circs_pct", 51),

            ("nf_conntimeout_clients", 606),

            ("sendme_accept_min_version", 31),

            ("sendme_emit_min_version", 32),

        ];

        let ignored = p.saturating_update(mp.iter().map(|(a, b)| (a, b)));

        assert!(ignored.is_empty());

        assert_eq!(p.bw_weight_scale.get(), 10);

        assert!(bool::from(p.cbt_learning_disabled));

        assert_eq!(p.cbt_num_xm_modes.get(), 11);

        assert_eq!(p.cbt_success_count.get(), 12);

        assert_eq!(p.cbt_max_timeouts.get(), 13);

        assert_eq!(p.cbt_min_circs_for_estimate.get(), 5);

        assert_eq!(p.cbt_timeout_quantile.as_percent().get(), 61);

        assert_eq!(p.cbt_abandon_quantile.as_percent().get(), 15);

        assert_eq!(

            Duration::try_from(p.unused_client_circ_timeout_while_learning_cbt).unwrap(),

            Duration::from_secs(1900)

        );

        assert_eq!(

            Duration::try_from(p.cbt_min_timeout).unwrap(),

            Duration::from_millis(2020)

        );

        assert_eq!(

            Duration::try_from(p.cbt_initial_timeout).unwrap(),

            Duration::from_millis(2050)

        );

        assert_eq!(

            Duration::try_from(p.cbt_testing_delay).unwrap(),

            Duration::from_secs(110)

        );

        assert_eq!(p.cbt_max_open_circuits_for_testing.get(), 14);

        assert_eq!(p.circuit_window.get(), 999);

        assert_eq!(

            Duration::try_from(p.circuit_priority_half_life).unwrap(),

            Duration::from_millis(222)

        );

        assert!(!bool::from(p.extend_by_ed25519_id));

        assert_eq!(p.min_circuit_path_threshold.as_percent().get(), 51);

        assert_eq!(

            Duration::try_from(p.unused_client_circ_timeout).unwrap(),

            Duration::from_secs(606)

        );

        assert_eq!(p.sendme_accept_min_version.get(), 31);

        assert_eq!(p.sendme_emit_min_version.get(), 32);

        assert_eq!(

            Duration::try_from(p.guard_lifetime_unconfirmed).unwrap(),

            Duration::from_secs(86400 * 36)

        );

        assert_eq!(

            Duration::try_from(p.guard_lifetime_confirmed).unwrap(),

            Duration::from_secs(86400 * 37)

        );

        assert_eq!(

            Duration::try_from(p.guard_internet_likely_down).unwrap(),

            Duration::from_secs(38)

        );

        assert_eq!(p.guard_max_sample_size.get(), 39);

        assert_eq!(p.guard_max_sample_threshold.as_percent().get(), 40);

        assert_eq!(p.guard_filtered_min_sample_size.get(), 41);

        assert_eq!(p.guard_n_primary.get(), 42);

        assert_eq!(p.guard_use_parallelism.get(), 43);

        assert_eq!(p.guard_dir_use_parallelism.get(), 44);

        assert_eq!(

            Duration::try_from(p.guard_nonprimary_connect_timeout).unwrap(),

            Duration::from_secs(45)

        );

        assert_eq!(

            Duration::try_from(p.guard_nonprimary_idle_timeout).unwrap(),

            Duration::from_secs(46)

        );

        assert_eq!(

            Duration::try_from(p.guard_remove_unlisted_after).unwrap(),

            Duration::from_secs(86400 * 47)

        );

        assert_eq!(p.guard_meaningful_restriction.as_percent().get(), 12);

        assert_eq!(p.guard_extreme_restriction.as_percent().get(), 3);

    }

}