//! core_info — informational commands: WHOIS, WHO, LUSERS, MOTD, VERSION.

use crate::command::{CmdResult, Command};
use crate::numeric::*;
use crate::server::{Server, VERSION};
use crate::users::User;
use crate::Uid;

pub fn commands() -> Vec<Box<dyn Command>> {
    vec![
        Box::new(Whois),
        Box::new(Who),
        Box::new(Lusers),
        Box::new(Motd),
        Box::new(VersionCmd),
        Box::new(Links),
        Box::new(SslInfo),
    ]
}

/// SSLINFO — report a user's TLS status and client-cert fingerprint (InspIRCd
/// `m_sslinfo`). You may query yourself; querying another user requires oper.
struct SslInfo;
impl Command for SslInfo {
    fn name(&self) -> &'static str {
        "SSLINFO"
    }
    fn min_params(&self) -> usize {
        1
    }
    fn handle(&self, s: &mut Server, uid: Uid, params: &[String]) -> CmdResult {
        let target = params[0].clone();
        let Some(tuid) = s.find_nick(&target) else {
            s.numeric(
                uid,
                ERR_NOSUCHNICK,
                &format!("{target} :No such nick/channel"),
            );
            return CmdResult::Fail;
        };
        if tuid != uid && !s.is_oper(uid) {
            s.numeric(uid, ERR_NOPRIVILEGES, ":You may only SSLINFO yourself");
            return CmdResult::Fail;
        }
        let asker = s
            .users
            .get(&uid)
            .map(|u| u.nick.clone())
            .unwrap_or_else(|| "*".to_string());
        let (nick, secure, certfp) = {
            let u = &s.users[&tuid];
            (u.nick.clone(), u.secure, u.certfp.clone())
        };
        let tls = if secure { "yes" } else { "no" };
        let fp = certfp.unwrap_or_else(|| "none".to_string());
        s.send(
            uid,
            format!(
                ":{} NOTICE {asker} :SSLINFO {nick}: TLS={tls} certfp={fp}",
                s.name
            ),
        );
        CmdResult::Ok
    }
}

/// LINKS — the servers this one knows about (itself + every linked peer).
struct Links;
impl Command for Links {
    fn name(&self) -> &'static str {
        "LINKS"
    }
    fn handle(&self, s: &mut Server, uid: Uid, _params: &[String]) -> CmdResult {
        s.numeric(
            uid,
            RPL_LINKS,
            &format!("{} {} :0 {}", s.name, s.name, s.server_desc),
        );
        let mut rows: Vec<(String, String)> = s
            .servers
            .values()
            .map(|sv| (sv.name.clone(), sv.desc.clone()))
            .collect();
        rows.sort();
        for (name, desc) in rows {
            s.numeric(uid, RPL_LINKS, &format!("{name} {} :1 {desc}", s.name));
        }
        s.numeric(uid, RPL_ENDOFLINKS, "* :End of /LINKS list");
        CmdResult::Ok
    }
}

struct Whois;
impl Command for Whois {
    fn name(&self) -> &'static str {
        "WHOIS"
    }
    fn min_params(&self) -> usize {
        1
    }
    fn handle(&self, s: &mut Server, uid: Uid, params: &[String]) -> CmdResult {
        let tnick = params[0]
            .split(',')
            .next()
            .unwrap_or(&params[0])
            .to_string();
        let Some(tuid) = s.find_nick(&tnick) else {
            // maybe they're on another server
            if let Some((uuid, _)) = s.find_remote(&tnick) {
                if let Some(ru) = s.remote_users.get(&uuid) {
                    let srv = s
                        .servers
                        .get(&ru.sid)
                        .map(|sv| sv.name.clone())
                        .unwrap_or_else(|| ru.sid.clone());
                    s.numeric(
                        uid,
                        RPL_WHOISUSER,
                        &format!("{} {} {} * :{}", ru.nick, ru.ident, ru.host, ru.realname),
                    );
                    s.numeric(
                        uid,
                        RPL_WHOISSERVER,
                        &format!("{} {srv} :remote user", ru.nick),
                    );
                    if let Some(a) = &ru.account {
                        s.numeric(
                            uid,
                            RPL_WHOISACCOUNT,
                            &format!("{} {a} :is logged in as", ru.nick),
                        );
                    }
                    s.numeric(
                        uid,
                        RPL_ENDOFWHOIS,
                        &format!("{} :End of /WHOIS list", ru.nick),
                    );
                    return CmdResult::Ok;
                }
            }
            s.numeric(
                uid,
                ERR_NOSUCHNICK,
                &format!("{tnick} :No such nick/channel"),
            );
            s.numeric(uid, RPL_ENDOFWHOIS, &format!("{tnick} :End of /WHOIS list"));
            return CmdResult::Fail;
        };
        let asker_oper = s.is_oper(uid);
        let is_self = tuid == uid;
        let keys: Vec<String> = s.users[&tuid].channels.iter().cloned().collect();
        let (
            nick,
            ident,
            disp,
            realname,
            realhost,
            realip,
            secure,
            oper,
            bot,
            hideoper,
            hidechans,
            account,
            last_active,
            signon,
            certfp,
            swhois,
            showwhois,
        ) = {
            let u = &s.users[&tuid];
            (
                u.nick.clone(),
                u.ident.clone(),
                u.host_display().to_string(),
                u.realname.clone(),
                u.host.clone(),
                u.addr.ip().to_string(),
                u.secure,
                u.flags.oper,
                u.flags.bot,
                u.flags.hideoper,
                u.flags.hidechans,
                u.account.clone(),
                u.last_active,
                u.signon,
                u.certfp.clone(),
                u.ext
                    .get::<crate::coremods::core_oper::Swhois>()
                    .map(|w| w.0.clone()),
                u.flags.showwhois,
            )
        };
        let chans: Vec<String> = keys
            .iter()
            .filter_map(|k| s.channels.get(k).map(|c| c.name.clone()))
            .collect();
        s.numeric(
            uid,
            RPL_WHOISUSER,
            &format!("{nick} {ident} {disp} * :{realname}"),
        );
        if bot {
            s.numeric(uid, RPL_WHOISBOT, &format!("{nick} :is a bot"));
        }
        s.numeric(
            uid,
            RPL_WHOISSERVER,
            &format!("{nick} {} :echoIRCd", s.name),
        );
        // +I hides the channel list from everyone but the user themselves + opers
        if !chans.is_empty() && (is_self || asker_oper || !hidechans) {
            s.numeric(
                uid,
                RPL_WHOISCHANNELS,
                &format!("{nick} :{}", chans.join(" ")),
            );
        }
        // 313: is an IRC operator (hidden by +H unless the asker is an oper)
        if oper && (!hideoper || asker_oper) {
            s.numeric(
                uid,
                RPL_WHOISOPERATOR,
                &format!("{nick} :is an IRC operator"),
            );
        }
        // 320: oper-set SWHOIS line. No redundant target-nick param — just the
        // text — so clients that don't special-case 320 don't echo the nick.
        if let Some(line) = &swhois {
            s.numeric(uid, RPL_WHOISSPECIAL, &format!(":{line}"));
        }
        // security groups (public ones to all; opers/self see private ones too)
        let groups = crate::modules::securitygroups::user_groups(s, tuid, is_self || asker_oper);
        if !groups.is_empty() {
            s.numeric(
                uid,
                RPL_WHOISSPECIAL,
                &format!(":is in security groups: {}", groups.join(", ")),
            );
        }
        // reputation score (opers only, when enabled)
        if asker_oper && s.rep_whois {
            let score = crate::modules::reputation::score_of(s, tuid);
            s.numeric(
                uid,
                RPL_WHOISSPECIAL,
                &format!(":has a reputation score of {score}"),
            );
        }
        // opers can see through the cloak to the real host/ip
        if asker_oper && disp != realhost {
            s.numeric(
                uid,
                RPL_WHOISHOST,
                &format!("{nick} :is connecting from {ident}@{realhost} {realip}"),
            );
        }
        // 330: logged in to a services account
        if let Some(acct) = &account {
            s.numeric(
                uid,
                RPL_WHOISACCOUNT,
                &format!("{nick} {acct} :is logged in as"),
            );
        }
        // sslinfo: advertise a secure (TLS) connection
        if secure {
            s.numeric(
                uid,
                RPL_WHOISSECURE,
                &format!("{nick} :is using a secure connection"),
            );
        }
        // client-cert fingerprint (CertFP) — shown to the user themselves and opers
        if let Some(fp) = &certfp {
            if is_self || asker_oper {
                s.numeric(
                    uid,
                    RPL_WHOISCERTFP,
                    &format!("{nick} :has client certificate fingerprint {fp}"),
                );
            }
        }
        // 317: idle time + signon time
        let idle = crate::server::now().saturating_sub(last_active);
        s.numeric(
            uid,
            RPL_WHOISIDLE,
            &format!("{nick} {idle} {signon} :seconds idle, signon time"),
        );
        // +W showwhois — tell the target that someone looked them up
        if showwhois && !is_self {
            let by = s.users.get(&uid).map(|u| u.prefix()).unwrap_or_default();
            s.send(
                tuid,
                format!(":{} NOTICE {nick} :*** {by} did a /WHOIS on you", s.name),
            );
        }
        s.numeric(uid, RPL_ENDOFWHOIS, &format!("{nick} :End of /WHOIS list"));
        CmdResult::Ok
    }
}

struct Who;
impl Command for Who {
    fn name(&self) -> &'static str {
        "WHO"
    }
    fn min_params(&self) -> usize {
        1
    }
    fn handle(&self, s: &mut Server, uid: Uid, params: &[String]) -> CmdResult {
        let target = &params[0];
        // WHOX: an options token containing '%' selects the reply fields (354).
        // `WHO <target> <filter>%<fields>[,<querytype>]`, e.g. `WHO #c %cuhnat,152`.
        let whox = params
            .get(1)
            .and_then(|o| o.split_once('%'))
            .map(|(_, spec)| {
                let (fields, qtype) = spec.split_once(',').unwrap_or((spec, ""));
                (fields.to_string(), qtype.to_string())
            });
        let asker_oper = s.is_oper(uid);
        let multi = s
            .users
            .get(&uid)
            .map(|u| u.caps.multi_prefix)
            .unwrap_or(false);

        // (uid, channel-name-or-"*", prefix-string) for each user to report
        let rows: Vec<(Uid, String, String)> = if target.starts_with('#') {
            match s.channels.get(&target.to_ascii_lowercase()) {
                // +s/+p: don't reveal a secret/private channel's members to
                // non-members (opers excepted)
                Some(ch)
                    if (ch.modes.secret || ch.modes.private)
                        && !ch.members.contains_key(&uid)
                        && !asker_oper =>
                {
                    Vec::new()
                }
                Some(ch) => {
                    let name = ch.name.clone();
                    ch.members
                        .iter()
                        .map(|(&m, mem)| {
                            let p = if multi {
                                mem.all_prefixes()
                            } else {
                                mem.prefix_char().to_string()
                            };
                            (m, name.clone(), p)
                        })
                        .collect()
                }
                None => Vec::new(),
            }
        } else if let Some(tuid) = s.find_nick(target) {
            vec![(tuid, "*".to_string(), String::new())]
        } else {
            Vec::new()
        };

        let now = crate::server::now();
        for (m, chan, pfx) in rows {
            let (code, row) = {
                let Some(u) = s.users.get(&m) else { continue };
                // flags: H (here) / G (gone/away), then * for opers, then prefixes
                let mut flags = String::from(if u.flags.away.is_some() { "G" } else { "H" });
                if u.flags.oper && (!u.flags.hideoper || asker_oper) {
                    flags.push('*');
                }
                flags.push_str(&pfx);
                match &whox {
                    Some((fields, qtype)) => (
                        RPL_WHOSPCRPL,
                        whox_row(
                            &s.name,
                            u,
                            &chan,
                            &flags,
                            fields,
                            qtype,
                            asker_oper,
                            m == uid,
                            now,
                        ),
                    ),
                    None => (
                        RPL_WHOREPLY,
                        format!(
                            "{chan} {} {} {} {} {flags} :0 {}",
                            u.ident,
                            u.host_display(),
                            s.name,
                            u.nick,
                            u.realname
                        ),
                    ),
                }
            };
            s.numeric(uid, code, &row);
        }
        s.numeric(uid, RPL_ENDOFWHO, &format!("{target} :End of /WHO list"));
        CmdResult::Ok
    }
}

/// Build a WHOX (354) reply body: the requested `fields` in their fixed output
/// order (never the request order), realname always last. Unknown field letters
/// are ignored. The real IP (`i`) is shown only to opers or to the user
/// themselves, so host-cloaking isn't defeated.
#[allow(clippy::too_many_arguments)]
fn whox_row(
    server: &str,
    u: &User,
    chan: &str,
    flags: &str,
    fields: &str,
    qtype: &str,
    asker_oper: bool,
    is_self: bool,
    now: u64,
) -> String {
    let has = |c: char| fields.contains(c);
    let mut parts: Vec<String> = Vec::new();
    if has('t') {
        parts.push(if qtype.is_empty() {
            "0".to_string()
        } else {
            qtype.to_string()
        });
    }
    if has('c') {
        parts.push(chan.to_string());
    }
    if has('u') {
        parts.push(u.ident.clone());
    }
    if has('i') {
        parts.push(if asker_oper || is_self {
            u.addr.ip().to_string()
        } else {
            "255.255.255.255".to_string()
        });
    }
    if has('h') {
        parts.push(u.host_display().to_string());
    }
    if has('s') {
        parts.push(server.to_string());
    }
    if has('n') {
        parts.push(u.nick.clone());
    }
    if has('f') {
        parts.push(flags.to_string());
    }
    if has('d') {
        parts.push("0".to_string()); // hopcount (local users)
    }
    if has('l') {
        parts.push(now.saturating_sub(u.last_active).to_string()); // idle seconds
    }
    if has('a') {
        parts.push(u.account.clone().unwrap_or_else(|| "0".to_string()));
    }
    if has('o') {
        parts.push("n/a".to_string()); // channel op-level
    }
    let mut row = parts.join(" ");
    if has('r') {
        if !row.is_empty() {
            row.push(' ');
        }
        row.push(':');
        row.push_str(&u.realname);
    }
    row
}

struct Lusers;
impl Command for Lusers {
    fn name(&self) -> &'static str {
        "LUSERS"
    }
    fn handle(&self, s: &mut Server, uid: Uid, _params: &[String]) -> CmdResult {
        s.numeric(
            uid,
            RPL_LUSERCLIENT,
            &format!(":There are {} users on 1 server", s.users.len()),
        );
        CmdResult::Ok
    }
}

struct Motd;
impl Command for Motd {
    fn name(&self) -> &'static str {
        "MOTD"
    }
    fn handle(&self, s: &mut Server, uid: Uid, _params: &[String]) -> CmdResult {
        s.send_motd(uid);
        CmdResult::Ok
    }
}

struct VersionCmd;
impl Command for VersionCmd {
    fn name(&self) -> &'static str {
        "VERSION"
    }
    fn before_reg(&self) -> bool {
        true
    }
    fn handle(&self, s: &mut Server, uid: Uid, _params: &[String]) -> CmdResult {
        s.send(
            uid,
            format!(":{} 351 * echoircd-{VERSION} {} :", s.name, s.name),
        );
        CmdResult::Ok
    }
}