//! Types and functions to configure a Tor Relay.

// TODO: It would be nice to remove the builder aspect of these config objects, as we don't need

// them for arti-relay. But I don't think we can do so while still using tor-config. See:

// https://gitlab.torproject.org/tpo/core/arti/-/issues/2253

mod listen;

use std::borrow::Cow;

use std::net::{IpAddr, SocketAddrV4, SocketAddrV6};

use std::path::PathBuf;

use derive_deftly::Deftly;

use derive_more::AsRef;

use directories::ProjectDirs;

use fs_mistrust::{Mistrust, MistrustBuilder};

use serde::{Deserialize, Serialize};

use std::sync::LazyLock;

use tor_chanmgr::{ChannelConfig, ChannelConfigBuilder};

use tor_circmgr::{CircuitTiming, PathConfig, PreemptiveCircuitConfig};

use tor_config::derive::prelude::*;

use tor_config::{

    ConfigBuildError, ExplicitOrAuto, extend_builder::extend_with_replace, mistrust::BuilderExt,

};

use tor_config_path::{CfgPath, CfgPathError, CfgPathResolver};

use tor_dircommon::config::{NetworkConfig, NetworkConfigBuilder};

use tor_dircommon::fallback::FallbackList;

use tor_guardmgr::bridge::BridgeConfig;

use tor_guardmgr::{VanguardConfig, VanguardConfigBuilder, VanguardMode};

use tor_keymgr::config::{ArtiKeystoreConfig, ArtiKeystoreConfigBuilder};

use tracing::metadata::Level;

use tracing_subscriber::filter::EnvFilter;

use crate::util::NonEmptyList;

use self::listen::Listen;

/// Paths used for default configuration files.

    // the base path resolver includes the 'ARTI_RELAY_CONFIG' variable

/// A [`CfgPathResolver`] with the base variables configured for a Tor relay.

///

/// A relay should have a single `CfgPathResolver` that is passed around where needed to ensure that

/// all parts of the relay are resolving paths consistently using the same variables.

/// If you need to resolve a path,

/// you likely want a reference to the existing resolver,

/// and not to create a new one here.

///

/// The supported variables are:

///   - `ARTI_RELAY_CACHE`:

///     An arti-specific cache directory.

///   - `ARTI_RELAY_CONFIG`:

///     An arti-specific configuration directory.

///   - `ARTI_RELAY_LOCAL_DATA`:

///     An arti-specific directory in the user's "local data" space.

///   - `PROGRAM_DIR`:

///     The directory of the currently executing binary.

///     See documentation for [`std::env::current_exe`] for security notes.

///   - `USER_HOME`:

///     The user's home directory.

///

/// These variables are implemented using the [`directories`] crate,

/// and so should use appropriate system-specific overrides under the hood.

/// (Some of those overrides are based on environment variables.)

/// For more information, see that crate's documentation.

//

// NOTE: We intentionally don't expose an `ARTI_RELAY_SHARED_DATA`

// (analogous to `ARTI_SHARED_DATA` in arti).

// This is almost certainly never intended over `ARTI_RELAY_LOCAL_DATA`,

// so by removing it we don't need to worry about bugs from mixing them up.

// We can introduce it later if really needed.

/// The directory holding the currently executing program.

/// A `ProjectDirs` object for Arti relays.

    /// lazy lock holding the ProjectDirs object.

    static PROJECT_DIRS: LazyLock<Option<ProjectDirs>> =

/// A configuration used by a TorRelay.

///

/// This is a builder so that it works with tor-config.

/// We don't expect to ever use it as a builder since we don't provide this as a public rust API.

#[derive(Clone, Deftly, Debug, Eq, PartialEq, AsRef)]

#[derive_deftly(TorConfig)]

#[deftly(tor_config(no_default_trait))]

#[non_exhaustive]

pub(crate) struct TorRelayConfig {

    /// Configuration for the "relay" part of the relay.

    // TODO: Add a better doc comment here once we figure out exactly how we want the config to be

    // structured.

    #[deftly(tor_config(sub_builder))]

    pub(crate) relay: RelayConfig,

    /// Information about the Tor network we want to connect to.

    #[deftly(tor_config(sub_builder))]

    pub(crate) tor_network: NetworkConfig,

    /// Logging configuration

    #[deftly(tor_config(sub_builder))]

    pub(crate) logging: LoggingConfig,

    /// Directories for storing information on disk

    #[deftly(tor_config(sub_builder))]

    pub(crate) storage: StorageConfig,

    /// Information about how to build paths through the network.

    #[deftly(tor_config(sub_builder))]

    pub(crate) channel: ChannelConfig,

    /// Configuration for system resources

    #[deftly(tor_config(sub_builder))]

    pub(crate) system: SystemConfig,

    /// Information about how to build paths through the network.

    // We don't expose this field in the config.

    #[deftly(tor_config(skip, build = "|_| Default::default()"))]

    // Needed to implement `CircMgrConfig`.

    #[as_ref]

    pub(crate) path_rules: PathConfig,

    /// Information about vanguards.

    // We don't expose this field in the config.

    #[deftly(tor_config(

        skip,

        build = r#"|_|

        VanguardConfigBuilder::default()

            .mode(ExplicitOrAuto::Explicit(VanguardMode::Disabled))

            .build()

            .expect("Could not build a disabled `VanguardConfig`")"#

    ))]

    // Needed to implement `CircMgrConfig`.

    #[as_ref]

    pub(crate) vanguards: VanguardConfig,

    /// Information about how to retry and expire circuits and request for circuits.

    // We don't expose this field in the config.

    #[deftly(tor_config(skip, build = "|_| Default::default()"))]

    // Needed to implement `CircMgrConfig`.

    #[as_ref]

    pub(crate) circuit_timing: CircuitTiming,

    /// Information about preemptive circuits.

    // We don't expose this field in the config.

    #[deftly(tor_config(skip, build = "|_| Default::default()"))]

    // Needed to implement `CircMgrConfig`.

    #[as_ref]

    pub(crate) preemptive_circuits: PreemptiveCircuitConfig,

}

impl tor_config::load::TopLevel for TorRelayConfig {

    type Builder = TorRelayConfigBuilder;

}

impl tor_circmgr::CircMgrConfig for TorRelayConfig {}

// Needed to implement `GuardMgrConfig`.

impl AsRef<FallbackList> for TorRelayConfig {

}

// Needed to implement `GuardMgrConfig`.

impl AsRef<[BridgeConfig]> for TorRelayConfig {

        // Relays don't use bridges.

}

impl tor_guardmgr::GuardMgrConfig for TorRelayConfig {

        // Relays don't use bridges.

}

/// Configuration for the "relay" part of the relay.

///

/// TODO: I'm not really sure what to call this yet. I'm expecting that we'll rename and reorganize

/// things as we add more options. But we should come back to this and update the name and/or doc

/// comment.

///

/// TODO: There's a high-level issue for discussing these options:

/// <https://gitlab.torproject.org/tpo/core/arti/-/issues/2252>

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

#[derive_deftly(TorConfig)]

#[deftly(tor_config(no_default_trait))]

pub(crate) struct RelayConfig {

    /// Addresses to listen on for incoming OR connections.

    #[deftly(tor_config(no_default))]

    pub(crate) listen: Listen,

    /// Addresses to advertise on the network for receiving OR connections.

    // For now, we've decided that we don't want to include any IP address auto-detection in

    // arti-relay, so we require users to provide the addresses to advertise. (So no `Option` and

    // `builder(default)` here).

    #[deftly(tor_config(no_default))]

    pub(crate) advertise: Advertise,

}

/// The address(es) to advertise on the network.

// TODO: We'll want to make sure we check that the addresses are valid before uploading them in a

// server descriptor (for example no `INADDR_ANY`, multicast, etc). We can't do that validation here

// during parsing, since we don't know exactly which addresses are valid or not. For example we

// don't know if local addresses are allowed as we don't know here whether the user plans to run a

// testing tor network. We also don't want to do the validation too late (for example when uploading

// the server descriptor) as it's better to validate at startup. A better place might be to perform

// the validation in the `RelayConfig` builder validate.

#[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]

pub(crate) struct Advertise {

    /// All relays must advertise an IPv4 address.

    ipv4: NonEmptyList<SocketAddrV4>,

    /// Relays may optionally advertise an IPv6 address.

    ipv6: Vec<SocketAddrV6>,

}

impl Advertise {

    /// Return all IP addresses (both IPv4 and IPv6).

}

/// Default log level.

pub(crate) const DEFAULT_LOG_LEVEL: Level = Level::INFO;

/// Logging configuration options.

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

#[derive_deftly(TorConfig)]

#[deftly(tor_config(pre_build = "Self::validate"))]

#[non_exhaustive]

pub(crate) struct LoggingConfig {

    /// Filtering directives that determine tracing levels as described at

    /// <https://docs.rs/tracing-subscriber/latest/tracing_subscriber/filter/targets/struct.Targets.html#impl-FromStr-for-Targets>

    ///

    /// You can override this setting with the `-l`, `--log-level` command line parameter.

    ///

    /// Example: "info,tor_proto::channel=trace"

    #[deftly(tor_config(default = "DEFAULT_LOG_LEVEL.to_string()"))]

    pub(crate) console: String,

}

impl LoggingConfigBuilder {

    /// Validate the options provided to the builder.

}

/// Configuration for where information should be stored on disk.

///

/// By default, cache information will be stored in `${ARTI_RELAY_CACHE}`, and

/// persistent state will be stored in `${ARTI_RELAY_LOCAL_DATA}`. That means that

/// _all_ programs using these defaults will share their cache and state data.

/// If that isn't what you want, you'll need to override these directories.

///

/// On unix, the default directories will typically expand to `~/.cache/arti`

/// and `~/.local/share/arti/` respectively, depending on the user's

/// environment. Other platforms will also use suitable defaults. For more

/// information, see the documentation for [`CfgPath`].

///

/// This section is for read/write storage.

///

/// You cannot change this section on a running relay.

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

#[derive_deftly(TorConfig)]

#[non_exhaustive]

pub(crate) struct StorageConfig {

    /// Location on disk for cached information.

    ///

    /// This follows the rules for `/var/cache`: "sufficiently old" filesystem objects

    /// in it may be deleted outside of the control of Arti,

    /// and Arti will continue to function properly.

    /// It is also fine to delete the directory as a whole, while Arti is not running.

    ///

    /// Should be accessed through the `cache_dir()` getter to provide better error messages when

    /// resolving the path.

    //

    // Usage note, for implementations of Arti components:

    //

    // When files in this directory are to be used by a component, the cache_dir

    // value should be passed through to the component as-is, and the component is

    // then responsible for constructing an appropriate sub-path (for example,

    // tor-dirmgr receives cache_dir, and appends components such as "dir_blobs".

    //

    // (This consistency rule is not current always followed by every component.)

    #[deftly(tor_config(default = "default_cache_dir()", setter(into)))]

    cache_dir: CfgPath,

    /// Location on disk for less-sensitive persistent state information.

    ///

    /// Should be accessed through the `state_dir()` getter to provide better error messages when

    /// resolving the path.

    // Usage note: see the note for `cache_dir`, above.

    #[deftly(tor_config(default = "default_state_dir()", setter(into)))]

    state_dir: CfgPath,

    /// Location on disk for the Arti keystore.

    #[deftly(tor_config(sub_builder))]

    keystore: ArtiKeystoreConfig,

    /// Configuration about which permissions we want to enforce on our files.

    // NOTE: This 'build_for_arti()' hard-codes the config field name as `permissions` and the

    // environment variable as `ARTI_FS_DISABLE_PERMISSION_CHECKS`. These things should be

    // configured by the application, not lower-level libraries, but some other lower-level

    // libraries like `tor-hsservice` also use 'build_for_arti()'. So we're stuck with it for now.

    // It might be confusing in the future if relays use some environment variables prefixed with

    // "ARTI_" and others with "ARTI_RELAY_", so we should probably stick to just "ARTI_".

    #[deftly(tor_config(

        sub_builder(build_fn = "build_for_arti"),

        extend_with = "extend_with_replace"

    ))]

    permissions: Mistrust,

}

impl StorageConfig {

    /// Return the FS permissions to use for state and cache directories.

    /// Return the fully expanded path of the state directory.

    /// Return the fully expanded path of the cache directory.

}

/// Configuration for system resources used by the relay.

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

#[derive_deftly(TorConfig)]

#[non_exhaustive]

pub(crate) struct SystemConfig {

    /// Memory limits (approximate)

    #[deftly(tor_config(sub_builder))]

    pub(crate) memory: tor_memquota::Config,

}

/// Return the default cache directory.

/// Return the default state directory.

/// Helper to return a `ConfigBuildError` if the path could not be resolved.

#[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)]

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

    use super::*;

    fn cfg_variables() -> impl IntoIterator<Item = (&'static str, PathBuf)> {

        let project_dirs = project_dirs().unwrap();

        let list = [

            ("ARTI_RELAY_CACHE", project_dirs.cache_dir()),

            ("ARTI_RELAY_CONFIG", project_dirs.config_dir()),

            ("ARTI_RELAY_LOCAL_DATA", project_dirs.data_local_dir()),

            ("PROGRAM_DIR", &get_program_dir().unwrap()),

            ("USER_HOME", tor_config_path::home().unwrap()),

        ];

        list.into_iter()

            .map(|(a, b)| (a, b.to_owned()))

            .collect::<Vec<_>>()

    }

    #[cfg(not(target_family = "windows"))]

    #[test]

    fn expand_variables() {

        let path_resolver = base_resolver();

        for (var, val) in cfg_variables() {

            let p = CfgPath::new(format!("${{{var}}}/example"));

            assert_eq!(p.to_string(), format!("${{{var}}}/example"));

            let expected = val.join("example");

            assert_eq!(p.path(&path_resolver).unwrap().to_str(), expected.to_str());

        }

        let p = CfgPath::new("${NOT_A_REAL_VAR}/example".to_string());

        assert!(p.path(&path_resolver).is_err());

    }

    #[cfg(target_family = "windows")]

    #[test]

    fn expand_variables() {

        let path_resolver = base_resolver();

        for (var, val) in cfg_variables() {

            let p = CfgPath::new(format!("${{{var}}}\\example"));

            assert_eq!(p.to_string(), format!("${{{var}}}\\example"));

            let expected = val.join("example");

            assert_eq!(p.path(&path_resolver).unwrap().to_str(), expected.to_str());

        }

        let p = CfgPath::new("${NOT_A_REAL_VAR}\\example".to_string());

        assert!(p.path(&path_resolver).is_err());

    }

}