use ldap3_proto::LdapMsg;
use ldap3_proto::proto::LdapOp;

use crate::db::{Database, DatabaseInterface};
use crate::error::GlobalError;
use crate::ldap::{
    LdapClientState, LdapStream, LdapStreamError, op_bind, op_ext, search_by_mail_filter,
};
use crate::listener::Listener;

pub async fn ldap_listen<D: DatabaseInterface>(listener: Listener, db: Database<D>) {
    // If the connection is None, it's because the client aborted early
    // so there's nothing to do about it.
    loop {
        match listener.accept_ldap().await {
            Ok(Some(stream)) => {
                let db = db.clone();
                tokio::spawn(ldap_handler(stream, db));
            }
            Ok(None) => {
                panic!("LDAP listener closed");
            }
            Err(e) => {
                panic!("Failed to listen on LDAP listener");
            }
        }
    }
}

#[tracing::instrument(name = "ldap", skip(stream, db), fields(session = %stream.session))]
pub async fn ldap_handler<D: DatabaseInterface>(mut stream: LdapStream, mut db: Database<D>) {
    tracing::info! {
        remote_addr = ?stream.remote_addr,
        "New client connection"
    };

    let mut state = LdapClientState::new();

    loop {
        match stream.next().await {
            Ok(msg) => match ldap_handler_inner(&mut stream, msg, &mut state, &mut db).await {
                Ok(should_keep_alive) => {
                    if !should_keep_alive {
                        tracing::debug!("Finished connection");
                        return;
                    }
                }
                Err(e) => {
                    tracing::debug!(
                        reason = ?e,
                        "Failed to respond"
                    );
                    return;
                }
            },
            Err(e) => {
                tracing::debug!(
                    reason = ?e,
                    "Closing connection"
                );
                return;
            }
        }
    }
}

/// Return true to keep the connection going, false to close it.
#[tracing::instrument(name = "ldap-handler", skip(client_state, db, stream))]
pub async fn ldap_handler_inner<D: DatabaseInterface>(
    stream: &mut LdapStream,
    msg: LdapMsg,
    client_state: &mut LdapClientState,
    db: &mut Database<D>,
) -> Result<bool, LdapStreamError> {
    tracing::debug!(msg = ?msg, "Received LDAP message");
    match msg {
        // Disconnect
        LdapMsg {
            msgid: _,
            op: LdapOp::UnbindRequest,
            ctrl: _,
        } => {
            client_state.unbind();
            // TODO: keep the connection open?
            Ok(true)
        }
        LdapMsg {
            msgid,
            op: LdapOp::ExtendedRequest(ler),
            ctrl: _,
        } => {
            op_ext(stream, ler, msgid, client_state).await?;
            Ok(true)
        }
        LdapMsg {
            msgid,
            op: LdapOp::BindRequest(lbr),
            ctrl: _,
        } => {
            if let Some(bound_dn) = op_bind(stream, db, lbr, msgid).await? {
                tracing::debug!("Successful bind");
                client_state.bind(bound_dn);
                Ok(true)
            } else {
                client_state.unbind();
                tracing::debug!("Failed bind or anonymous bind");
                // We keep the connection open in case it's an anonymous bind
                Ok(true)
            }
        }
        LdapMsg {
            msgid,
            op: LdapOp::SearchRequest(sr),
            // TODO: ctrl for pagination
            ctrl: _,
        } => {
            search_by_mail_filter(stream, db, sr, msgid).await?;
            Ok(true)
        }
        // Unsupported message
        _ => {
            tracing::warn!("Unsupported client message, closing connection");
            Ok(false)
        }
    }
}