/* This file is part of DarkFi (https://dark.fi)
 *
 * Copyright (C) 2020-2026 Dyne.org foundation
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

use std::collections::HashMap;

use structopt::StructOpt;
use url::Url;

use crate::error::{Error, Result};

type BlacklistEntry = (String, Vec<String>, Vec<u16>);

/// Ban policies definitions.
///
/// If the ban policy is set to `Relaxed` will not ban peers in case
/// they send a message without a corresponding MessageDispatcher.
/// This is useful for nodes that may not be subscribed to protocols,
/// such as Lilith. For most uses this should be set to `Strict`.
///
/// TODO: this will be deprecated when we introduce the p2p resource
/// mananger.
#[derive(Clone, Debug, Default, PartialEq, serde::Deserialize, serde::Serialize)]
#[serde(rename_all = "lowercase")]
pub enum BanPolicy {
    #[default]
    Strict,

    Relaxed,
}

/// P2P network settings. The scope of this is a P2P network instance
/// configured by the library user.
#[derive(Debug, Clone)]
pub struct Settings {
    /// Only used for debugging, compromises privacy when set
    pub node_id: String,
    /// P2P accept addresses the instance listens on for inbound connections
    pub inbound_addrs: Vec<Url>,
    /// P2P external addresses the instance advertises so other peers can
    /// reach us and connect to us, as long as inbound addrs are configured
    pub external_addrs: Vec<Url>,
    /// Peer nodes to manually connect to
    pub peers: Vec<Url>,
    /// Seed nodes to connect to for peer discovery and/or advertising our
    /// own external addresses
    pub seeds: Vec<Url>,
    /// Magic bytes should be unique per P2P network.
    /// Avoid bleeding of networks.
    pub magic_bytes: MagicBytes,
    /// Application version, used for convenient protocol matching
    pub app_version: semver::Version,
    /// Application Identifier
    pub app_name: String,
    /// Whitelisted network transports for outbound connections
    pub active_profiles: Vec<String>,
    /// Transports allowed to be mixed (tcp, tcp+tls, tor, tor+tls)
    /// When transport is added to this list the corresponding transport
    /// in active_profiles is used to connect to the node.
    /// Supported mixing scenarios include
    /// active_profile | mixed_profile
    ///        tor        |     tcp
    ///       tor+tls     |    tcp+tls
    ///       socks5      |      tor
    ///       socks5      |      tcp
    ///      socks5+tls   |    tor+tls
    ///      socks5+tls   |    tcp+tls
    pub mixed_profiles: Vec<String>,
    /// Tor socks5 proxy to connect to when socks5 or socks5+tls are added to active profiles
    /// and transport mixing is enabled
    pub tor_socks5_proxy: Option<Url>,
    /// Nym socks5 proxy to connect to when socks5 or socks5+tls are added to active profiles
    /// and transport mixing is enabled
    pub nym_socks5_proxy: Option<Url>,
    /// I2p Socks5 proxy to connect to i2p eepsite (hidden services)
    pub i2p_socks5_proxy: Url,
    /// Outbound connection slots number, this many connections will be
    /// attempted. (This does not include manual connections)
    pub outbound_connections: usize,
    /// Inbound connection slots number, this many active listening connections
    /// will be allowed. (This does not include manual connections)
    pub inbound_connections: usize,
    /// Allow localnet hosts
    pub localnet: bool,
    /// Cooling off time for peer discovery when unsuccessful
    pub outbound_peer_discovery_cooloff_time: u64,
    /// Time between peer discovery attempts
    pub outbound_peer_discovery_attempt_time: u64,
    /// Maximum number of addresses (with preferred transports) to receive from
    /// seeds and peers.
    /// If undefined, `outbound_connections` will be used instead.
    pub getaddrs_max: Option<u32>,
    /// P2P datastore path
    pub p2p_datastore: Option<String>,
    /// Hostlist storage path
    pub hostlist: Option<String>,
    /// Pause interval within greylist refinery process
    pub greylist_refinery_interval: u64,
    /// Percent of connections to come from the whitelist
    pub white_connect_percent: usize,
    /// Number of goldlist connections
    pub gold_connect_count: usize,
    /// If this is true, strictly follow the gold_connect_count and
    /// white_connect_percent settings. Otherwise, connect to greylist
    /// entries if we have no white or gold connections.
    pub slot_preference_strict: bool,
    /// Number of seconds with no connections after which refinery
    /// process is paused.
    pub time_with_no_connections: u64,
    /// Nodes to avoid interacting with for the duration of the program,
    /// in the format ["host", ["scheme", "scheme"], [port, port]]
    /// If scheme is left empty it will default to "tcp+tls".
    /// If ports are left empty all ports from this peer will be blocked.
    pub blacklist: Vec<BlacklistEntry>,
    /// Do not ban nodes that send messages without dispatchers if set
    /// to `Relaxed`. For most uses, should be set to `Strict`.
    pub ban_policy: BanPolicy,
    /// Mapping of transport/scheme to Network Profile
    pub profiles: HashMap<String, NetworkProfile>,
}

impl Default for Settings {
    fn default() -> Self {
        let version = option_env!("CARGO_PKG_VERSION").unwrap_or("0.0.0");
        let app_version = semver::Version::parse(version).unwrap();
        let app_name = option_env!("CARGO_PKG_NAME").unwrap_or("").to_string();

        Self {
            node_id: String::new(),
            inbound_addrs: vec![],
            external_addrs: vec![],
            magic_bytes: Default::default(),
            peers: vec![],
            seeds: vec![],
            app_version,
            app_name,
            active_profiles: vec![],
            mixed_profiles: vec![],
            tor_socks5_proxy: None,
            nym_socks5_proxy: None,
            i2p_socks5_proxy: Url::parse("socks5://127.0.0.1:4447").unwrap(),
            outbound_connections: 8,
            inbound_connections: 8,
            localnet: false,
            outbound_peer_discovery_cooloff_time: 30,
            outbound_peer_discovery_attempt_time: 5,
            getaddrs_max: None,
            p2p_datastore: None,
            hostlist: None,
            greylist_refinery_interval: 15,
            white_connect_percent: 70,
            gold_connect_count: 2,
            slot_preference_strict: false,
            time_with_no_connections: 30,
            blacklist: vec![],
            ban_policy: BanPolicy::Strict,
            profiles: HashMap::new(),
        }
    }
}

impl Settings {
    /// Returns `outbound_connect_timeout` for a specific profile.
    pub fn outbound_connect_timeout(&self, profile: &str) -> u64 {
        self.profiles.get(profile).unwrap_or(&NetworkProfile::default()).outbound_connect_timeout
    }

    /// Returns the maximum `outbound_connect_timeout` across all profiles,
    /// selecting a conservative value suitable for the slowest network profile.
    pub fn outbound_connect_timeout_max(&self) -> u64 {
        self.profiles
            .values()
            .map(|p| p.outbound_connect_timeout)
            .max()
            .unwrap_or(NetworkProfile::default().outbound_connect_timeout)
    }

    pub fn channel_heartbeat_interval(&self, profile: &str) -> u64 {
        self.profiles.get(profile).unwrap_or(&NetworkProfile::default()).channel_heartbeat_interval
    }

    pub fn channel_handshake_timeout(&self, profile: &str) -> u64 {
        self.profiles.get(profile).unwrap_or(&NetworkProfile::default()).channel_handshake_timeout
    }
}

/// Distinguishes distinct P2P networks
#[derive(serde::Deserialize, Debug, Clone)]
pub struct MagicBytes(pub [u8; 4]);

impl Default for MagicBytes {
    fn default() -> Self {
        Self([0xd9, 0xef, 0xb6, 0x7d])
    }
}

/// Defines the network settings so we can have P2P configurations in
/// TOML files.
#[derive(Clone, Debug, serde::Deserialize, structopt::StructOpt, structopt_toml::StructOptToml)]
#[structopt()]
pub struct SettingsOpt {
    /// P2P accept address node listens to for inbound connections
    #[serde(default)]
    #[structopt(long = "accept")]
    pub inbound: Vec<Url>,

    /// Outbound connection slots number
    #[structopt(long = "outbound-slots")]
    pub outbound_connections: Option<usize>,

    /// Inbound connection slots number
    #[structopt(long = "inbound-slots")]
    pub inbound_connections: Option<usize>,

    #[serde(default)]
    #[structopt(skip)]
    /// Magic bytes used to distinguish P2P distinct networks and
    /// avoid nodes bleeding due to user config error.
    pub magic_bytes: MagicBytes,

    /// P2P external addresses node advertises so other peers can
    /// reach us and connect to us, as long as inbound addresses
    /// are also configured
    #[serde(default)]
    #[structopt(long)]
    pub external_addrs: Vec<Url>,

    /// Peer nodes to manually connect to
    #[serde(default)]
    #[structopt(long)]
    pub peers: Vec<Url>,

    /// Seed nodes to connect to for peers retrieval and/or
    /// advertising our own external addresses
    #[serde(default)]
    #[structopt(long)]
    pub seeds: Vec<Url>,

    /// Connection establishment timeout in seconds
    #[structopt(skip)]
    pub outbound_connect_timeout: Option<u64>,

    /// Exchange versions (handshake) timeout in seconds
    #[structopt(skip)]
    pub channel_handshake_timeout: Option<u64>,

    /// Ping-pong exchange execution interval in seconds
    #[structopt(skip)]
    pub channel_heartbeat_interval: Option<u64>,

    /// Only used for debugging. Compromises privacy when set.
    #[serde(default)]
    #[structopt(skip)]
    pub node_id: String,

    /// Preferred transports for outbound connections
    #[serde(default)]
    #[structopt(long = "network-profiles")]
    pub active_profiles: Option<Vec<String>>,

    /// Transports allowed to be mixed (tcp, tcp+tls, tor, tor+tls).
    /// When transport is added to this list the corresponding transport
    /// in active_profiles is used to connect to the node.
    /// Supported mixing scenarios include
    /// tor => tcp, tor+tls => tcp+tls,
    /// socks5 => tor, socks5 => tcp,
    /// socks5+tls => tor+tls, socks5+tls => tcp+tls
    /// where the first one overrides the second.
    #[serde(default)]
    #[structopt(long = "mixed-profiles")]
    pub mixed_profiles: Option<Vec<String>>,

    /// Tor socks5 proxy to connect to when socks5 or socks5+tls are added to active profiles
    /// and transport mixing is enabled
    #[structopt(long)]
    pub tor_socks5_proxy: Option<Url>,

    /// Nym socks5 proxy to connect to when socks5 or socks5+tls are added to active profiles
    /// and transport mixing is enabled
    #[structopt(long)]
    pub nym_socks5_proxy: Option<Url>,

    /// I2p Socks5 proxy to connect to i2p eepsite (hidden services)
    #[structopt(long)]
    pub i2p_socks5_proxy: Option<Url>,

    /// If this is true, strictly follow the gold_connect_count and
    /// white_connect_percent settings. Otherwise, connect to greylist
    /// entries if we have no white or gold connections.
    #[serde(default)]
    #[structopt(long)]
    pub localnet: bool,

    /// Cooling off time for peer discovery when unsuccessful
    #[structopt(skip)]
    pub outbound_peer_discovery_cooloff_time: Option<u64>,

    /// Time between peer discovery attempts
    #[structopt(skip)]
    pub outbound_peer_discovery_attempt_time: Option<u64>,

    /// Maximum number of addresses (with preferred transports) to receive from
    /// seeds and peers.
    /// If undefined, `outbound_connections` will be used instead.
    #[structopt(skip)]
    pub getaddrs_max: Option<u32>,

    /// P2P datastore path
    #[serde(default)]
    #[structopt(long)]
    pub p2p_datastore: Option<String>,

    /// Hosts .tsv file to use
    #[serde(default)]
    #[structopt(long)]
    pub hostlist: Option<String>,

    /// Pause interval within greylist refinery process
    #[structopt(skip)]
    pub greylist_refinery_interval: Option<u64>,

    /// Number of whitelist connections
    #[structopt(skip)]
    pub white_connect_percent: Option<usize>,

    /// Number of goldlist connections
    #[structopt(skip)]
    pub gold_connect_count: Option<usize>,

    /// Allow localnet hosts
    #[serde(default)]
    #[structopt(long)]
    pub slot_preference_strict: bool,

    /// Number of seconds with no connections after which refinery
    /// process is paused.
    #[structopt(skip)]
    pub time_with_no_connections: Option<u64>,

    /// Nodes to avoid interacting with for the duration of the program,
    /// in the format ["host", ["scheme", "scheme"], [port, port]]
    /// If scheme is left empty it will default to "tcp+tls".
    /// If ports are left empty all ports from this peer will be blocked.
    #[serde(default)]
    #[structopt(skip)]
    pub blacklist: Vec<BlacklistEntry>,

    /// Do not ban nodes that send messages without dispatchers if set
    /// to `Relaxed`. For most uses, should be set to `Strict`.
    #[serde(default)]
    #[structopt(skip)]
    pub ban_policy: BanPolicy,

    /// Network Profile for each transport
    #[serde(default)]
    #[structopt(skip)]
    pub profiles: HashMap<String, NetworkProfileOpt>,
}

impl TryFrom<(&str, &str, SettingsOpt)> for Settings {
    type Error = Error;
    fn try_from(st: (&str, &str, SettingsOpt)) -> Result<Self> {
        let app_name = st.0.to_string();
        let app_version = semver::Version::parse(st.1)?;
        let opt = st.2;

        let def = Settings::default();
        let mut inbound_addrs = opt.inbound;
        let mut external_addrs = opt.external_addrs;
        let mut peers = opt.peers;
        let mut seeds = opt.seeds;
        let active_profiles = opt.active_profiles.unwrap_or(def.active_profiles);
        let mixed_profiles = opt.mixed_profiles.unwrap_or(def.mixed_profiles);

        // check all the active profiles that are not mixed are found in net.profiles
        for name in &active_profiles {
            if !mixed_profiles.contains(name) && !opt.profiles.contains_key(name) {
                return Err(Error::ConfigError(format!(
                    "Active profile '{name}' not defined in net.profiles"
                )));
            }
        }

        let profiles: HashMap<String, NetworkProfile> = opt
            .profiles
            .into_iter()
            .filter(|(k, _)| active_profiles.contains(k) && !mixed_profiles.contains(k))
            .map(|(k, v)| {
                inbound_addrs.extend_from_slice(&v.inbound);
                external_addrs.extend_from_slice(&v.external_addrs);
                peers.extend_from_slice(&v.peers);
                seeds.extend_from_slice(&v.seeds);
                (k.clone(), NetworkProfile::from_with_profile(v, &k))
            })
            .collect();

        Ok(Self {
            node_id: opt.node_id,
            inbound_addrs,
            external_addrs,
            magic_bytes: opt.magic_bytes,
            peers,
            seeds,
            app_version,
            app_name,
            active_profiles,
            mixed_profiles,
            tor_socks5_proxy: opt.tor_socks5_proxy,
            nym_socks5_proxy: opt.nym_socks5_proxy,
            i2p_socks5_proxy: opt.i2p_socks5_proxy.unwrap_or(def.i2p_socks5_proxy),
            outbound_connections: opt.outbound_connections.unwrap_or(def.outbound_connections),
            inbound_connections: opt.inbound_connections.unwrap_or(def.inbound_connections),
            localnet: opt.localnet,
            outbound_peer_discovery_cooloff_time: opt
                .outbound_peer_discovery_cooloff_time
                .unwrap_or(def.outbound_peer_discovery_cooloff_time),
            outbound_peer_discovery_attempt_time: opt
                .outbound_peer_discovery_attempt_time
                .unwrap_or(def.outbound_peer_discovery_attempt_time),
            getaddrs_max: opt.getaddrs_max,
            p2p_datastore: opt.p2p_datastore,
            hostlist: opt.hostlist,
            greylist_refinery_interval: opt
                .greylist_refinery_interval
                .unwrap_or(def.greylist_refinery_interval),
            white_connect_percent: opt.white_connect_percent.unwrap_or(def.white_connect_percent),
            gold_connect_count: opt.gold_connect_count.unwrap_or(def.gold_connect_count),
            slot_preference_strict: opt.slot_preference_strict,
            time_with_no_connections: opt
                .time_with_no_connections
                .unwrap_or(def.time_with_no_connections),
            blacklist: opt.blacklist,
            ban_policy: opt.ban_policy,
            profiles,
        })
    }
}

#[derive(Clone, Debug, serde::Deserialize, structopt::StructOpt, structopt_toml::StructOptToml)]
#[structopt()]
pub struct NetworkProfileOpt {
    /// P2P accept address node listens to for inbound connections
    #[serde(default)]
    #[structopt(long = "accept")]
    pub inbound: Vec<Url>,

    /// P2P external addresses node advertises so other peers can
    /// reach us and connect to us, as long as inbound addresses
    /// are also configured
    #[serde(default)]
    #[structopt(long)]
    pub external_addrs: Vec<Url>,

    /// Peer nodes to manually connect to
    #[serde(default)]
    #[structopt(long)]
    pub peers: Vec<Url>,

    /// Seed nodes to connect to for peers retrieval and/or
    /// advertising our own external addresses
    #[serde(default)]
    #[structopt(long)]
    pub seeds: Vec<Url>,

    /// Connection establishment timeout in seconds
    #[structopt(skip)]
    pub outbound_connect_timeout: Option<u64>,

    /// Exchange versions (handshake) timeout in seconds
    #[structopt(skip)]
    pub channel_handshake_timeout: Option<u64>,

    /// Ping-pong exchange execution interval in seconds
    #[structopt(skip)]
    pub channel_heartbeat_interval: Option<u64>,
}

/// Network Profile info unique for each profile/transport
#[derive(Debug, Clone)]
pub struct NetworkProfile {
    /// Outbound connection timeout (in seconds)
    pub outbound_connect_timeout: u64,
    /// Exchange versions (handshake) timeout (in seconds)
    pub channel_handshake_timeout: u64,
    /// Ping-pong exchange execution interval (in seconds)
    pub channel_heartbeat_interval: u64,
}

impl Default for NetworkProfile {
    fn default() -> Self {
        Self {
            outbound_connect_timeout: 15,
            channel_handshake_timeout: 10,
            channel_heartbeat_interval: 30,
        }
    }
}

impl NetworkProfile {
    /// Creates default [`NetworkProfile`] for non-clearnet profiles
    pub fn tor_default() -> Self {
        Self {
            outbound_connect_timeout: 65,
            channel_handshake_timeout: 55,
            channel_heartbeat_interval: 90,
        }
    }

    /// Creates [`NetworkProfile`] from [`NetworkProfileOpt`] based on the profile
    fn from_with_profile(opt: NetworkProfileOpt, profile: &str) -> Self {
        let def = if ["tcp", "tcp+tls", "quic"].contains(&profile) {
            NetworkProfile::default()
        } else {
            NetworkProfile::tor_default()
        };

        Self {
            outbound_connect_timeout: opt
                .outbound_connect_timeout
                .unwrap_or(def.outbound_connect_timeout),
            channel_handshake_timeout: opt
                .channel_handshake_timeout
                .unwrap_or(def.channel_handshake_timeout),
            channel_heartbeat_interval: opt
                .channel_heartbeat_interval
                .unwrap_or(def.channel_heartbeat_interval),
        }
    }
}