/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * This implements the WATCH and MONITOR commands: ways to more efficiently
 * (compared to ISON) keep track of a user's status.
 *
 *   MONITOR (supported by Charybdis)
 *     https://github.com/atheme/charybdis/blob/master/doc/monitor.txt
 *   WATCH (supported by Bahamut and UnrealIRCd)
 *     http://www.stack.nl/~jilles/cgi-bin/hgwebdir.cgi/irc-documentation-jilles/raw-file/tip/reference/draft-meglio-irc-watch-00.txt
 */

import { clearTimeout } from "resource://gre/modules/Timer.sys.mjs";
import { ircHandlerPriorities } from "resource:///modules/ircHandlerPriorities.sys.mjs";

function setStatus(aAccount, aNick, aStatus) {
  if (!aAccount.watchEnabled && !aAccount.monitorEnabled) {
    return false;
  }

  if (aStatus == "AWAY") {
    // We need to request the away message.
    aAccount.requestCurrentWhois(aNick);
  } else {
    // Clear the WHOIS information.
    aAccount.removeBuddyInfo(aNick);
  }

  let buddy = aAccount.buddies.get(aNick);
  if (!buddy) {
    return false;
  }
  buddy.setStatus(Ci.imIStatusInfo["STATUS_" + aStatus], "");
  return true;
}

function trackBuddyWatch(aNicks) {
  // aNicks is an array when WATCH is initialized, and a single nick
  // in all later calls.
  if (!Array.isArray(aNicks)) {
    // We update the trackQueue if an individual nick is being added,
    // so the nick will also be monitored after a reconnect.
    Object.getPrototypeOf(this).trackBuddy.call(this, aNicks);
    aNicks = [aNicks];
  }

  let nicks = aNicks.map(aNick => "+" + aNick);
  if (!nicks.length) {
    return;
  }

  let newWatchLength = this.watchLength + nicks.length;
  if (newWatchLength > this.maxWatchLength) {
    this.WARN(
      "Attempting to WATCH " +
        newWatchLength +
        " nicks; maximum size is " +
        this.maxWatchLength +
        "."
    );
    // TODO We should trim the list and add the extra users to an ISON queue,
    // but that's not currently implemented, so just hope the server doesn't
    // enforce it's own limit.
  }
  this.watchLength = newWatchLength;

  // Watch away as well as online.
  let params = [];
  if (this.watchAwayEnabled) {
    params.push("A");
  }
  let maxLength =
    this.maxMessageLength -
    2 -
    this.countBytes(this.buildMessage("WATCH", params));
  for (let nick of nicks) {
    if (this.countBytes(params + " " + nick) >= maxLength) {
      // If the message would be too long, first send this message.
      this.sendMessage("WATCH", params);
      // Reset for the next message.
      params = [];
      if (this.watchAwayEnabled) {
        params.push("A");
      }
    }
    params.push(nick);
  }
  this.sendMessage("WATCH", params);
}
function untrackBuddyWatch(aNick) {
  --this.watchLength;
  this.sendMessage("WATCH", "-" + aNick);
  Object.getPrototypeOf(this).untrackBuddy.call(this, aNick);
}

export var isupportWATCH = {
  name: "WATCH",
  // Slightly above default ISUPPORT priority.
  priority: ircHandlerPriorities.DEFAULT_PRIORITY + 10,
  isEnabled: () => true,

  commands: {
    WATCH(aMessage) {
      if (!aMessage.isupport.useDefault) {
        this.maxWatchLength = 128;
      } else {
        let size = parseInt(aMessage.isupport.value, 10);
        if (isNaN(size)) {
          return false;
        }
        this.maxWatchLength = size;
      }

      this.watchEnabled = true;

      // Clear our watchlist in case there is garbage in it.
      this.sendMessage("WATCH", "C");
      this.watchLength = 0;

      // Kill the ISON polling loop.
      clearTimeout(this._isOnTimer);

      return true;
    },

    WATCHOPTS(aMessage) {
      const watchOptToOption = {
        H: "watchMasksEnabled",
        A: "watchAwayEnabled",
      };

      // For each option, mark it as supported.
      aMessage.isupport.value.split("").forEach(function (aWatchOpt) {
        if (watchOptToOption.hasOwnProperty(aWatchOpt)) {
          this[watchOptToOption[aWatchOpt]] = true;
        }
      }, this);

      return true;
    },
  },
};

export var ircWATCH = {
  name: "WATCH",
  // Slightly above default IRC priority.
  priority: ircHandlerPriorities.DEFAULT_PRIORITY + 10,
  // Use WATCH if it is supported.
  isEnabled() {
    return !!this.watchEnabled;
  },

  commands: {
    251(aMessage) {
      // RPL_LUSERCLIENT
      // ":There are <integer> users and <integer> services on <integer> servers"
      // Assume that this will always be sent after the 005 handler on
      // connection registration. If WATCH is enabled, then set the new function
      // to keep track of nicks and send the messages to watch the nicks.

      // Ensure that any new buddies are set to be watched, and removed buddies
      // are no longer watched.
      this.trackBuddy = trackBuddyWatch;
      this.untrackBuddy = untrackBuddyWatch;

      // Build the watchlist from the current list of nicks.
      this.trackBuddy(this.trackQueue);

      // Fall through to other handlers since we're only using this as an entry
      // point and not actually handling the message.
      return false;
    },

    301(aMessage) {
      // RPL_AWAY
      // <nick> :<away message>
      // Set the received away message.
      let buddy = this.buddies.get(aMessage.params[1]);
      if (buddy) {
        buddy.setStatus(Ci.imIStatusInfo.STATUS_AWAY, aMessage.params[2]);
      }

      // Fall through to the other implementations after setting the status
      // message.
      return false;
    },

    303(aMessage) {
      // RPL_ISON
      // :*1<nick> *( " " <nick> )
      // We don't want ircBase to interfere with us, so override the ISON
      // handler to do nothing.
      return true;
    },

    512(aMessage) {
      // ERR_TOOMANYWATCH
      // Maximum size for WATCH-list is <watchlimit> entries
      this.ERROR(
        "Maximum size for WATCH list exceeded (" + this.watchLength + ")."
      );
      return true;
    },

    597(aMessage) {
      // RPL_REAWAY
      // <nickname> <username> <hostname> <awaysince> :<away reason>
      return setStatus(this, aMessage.params[1], "AWAY");
    },

    598(aMessage) {
      // RPL_GONEAWAY
      // <nickname> <username> <hostname> <awaysince> :<away reason>
      // We use a negative index as inspircd versions < 2.0.18 don't send
      // the user's nick as the first parameter (see bug 1078223).
      return setStatus(
        this,
        aMessage.params[aMessage.params.length - 5],
        "AWAY"
      );
    },

    599(aMessage) {
      // RPL_NOTAWAY
      // <nickname> <username> <hostname> <awaysince> :is no longer away
      // We use a negative index as inspircd versions < 2.0.18 don't send
      // the user's nick as the first parameter (see bug 1078223).
      return setStatus(
        this,
        aMessage.params[aMessage.params.length - 5],
        "AVAILABLE"
      );
    },

    600(aMessage) {
      // RPL_LOGON
      // <nickname> <username> <hostname> <signontime> :logged on
      return setStatus(this, aMessage.params[1], "AVAILABLE");
    },

    601(aMessage) {
      // RPL_LOGOFF
      // <nickname> <username> <hostname> <lastnickchange> :logged off
      return setStatus(this, aMessage.params[1], "OFFLINE");
    },

    602(aMessage) {
      // RPL_WATCHOFF
      // <nickname> <username> <hostname> <lastnickchange> :stopped watching
      return true;
    },

    603(aMessage) {
      // RPL_WATCHSTAT
      // You have <entrycount> and are on <onlistcount> WATCH entries
      // TODO I don't think we really need to care about this.
      return false;
    },

    604(aMessage) {
      // RPL_NOWON
      // <nickname> <username> <hostname> <lastnickchange> :is online
      return setStatus(this, aMessage.params[1], "AVAILABLE");
    },

    605(aMessage) {
      // RPL_NOWOFF
      // <nickname> <username> <hostname> <lastnickchange> :is offline
      return setStatus(this, aMessage.params[1], "OFFLINE");
    },

    606(aMessage) {
      // RPL_WATCHLIST
      // <entrylist>
      // TODO
      return false;
    },

    607(aMessage) {
      // RPL_ENDOFWATCHLIST
      // End of WATCH <parameter>
      // TODO
      return false;
    },

    608(aMessage) {
      // RPL_CLEARWATCH
      // Your WATCH list is now empty
      // Note that this is optional for servers to send, so ignore it.
      return true;
    },

    609(aMessage) {
      // RPL_NOWISAWAY
      // <nickname> <username> <hostname> <awaysince> :<away reason>
      return setStatus(this, aMessage.params[1], "AWAY");
    },
  },
};

export var isupportMONITOR = {
  name: "MONITOR",
  // Slightly above default ISUPPORT priority.
  priority: ircHandlerPriorities.DEFAULT_PRIORITY + 10,
  isEnabled: () => true,

  commands: {
    MONITOR(aMessage) {
      if (!aMessage.isupport.useDefault) {
        this.maxMonitorLength = Infinity;
      } else {
        let size = parseInt(aMessage.isupport.value, 10);
        if (isNaN(size)) {
          return false;
        }
        this.maxMonitorLength = size;
      }

      this.monitorEnabled = true;

      // Clear our monitor list in case there is garbage in it.
      this.sendMessage("MONITOR", "C");
      this.monitorLength = 0;

      // Kill the ISON polling loop.
      clearTimeout(this._isOnTimer);

      return true;
    },
  },
};

function trackBuddyMonitor(aNicks) {
  // aNicks is an array when MONITOR is initialized, and a single nick
  // in all later calls.
  if (!Array.isArray(aNicks)) {
    // We update the trackQueue if an individual nick is being added,
    // so the nick will also be monitored after a reconnect.
    Object.getPrototypeOf(this).trackBuddy.call(this, aNicks);
    aNicks = [aNicks];
  }

  let nicks = aNicks;
  if (!nicks.length) {
    return;
  }

  let newMonitorLength = this.monitorLength + nicks.length;
  if (newMonitorLength > this.maxMonitorLength) {
    this.WARN(
      "Attempting to MONITOR " +
        newMonitorLength +
        " nicks; maximum size is " +
        this.maxMonitorLength +
        "."
    );
    // TODO We should trim the list and add the extra users to an ISON queue,
    // but that's not currently implemented, so just hope the server doesn't
    // enforce it's own limit.
  }
  this.monitorLength = newMonitorLength;

  let params = [];
  let maxLength =
    this.maxMessageLength -
    2 -
    this.countBytes(this.buildMessage("MONITOR", "+"));
  for (let nick of nicks) {
    if (this.countBytes(params + " " + nick) >= maxLength) {
      // If the message would be too long, first send this message.
      this.sendMessage("MONITOR", ["+", params.join(",")]);
      // Reset for the next message.
      params = [];
    }
    params.push(nick);
  }
  this.sendMessage("MONITOR", ["+", params.join(",")]);
}
function untrackBuddyMonitor(aNick) {
  --this.monitorLength;
  this.sendMessage("MONITOR", ["-", aNick]);
  Object.getPrototypeOf(this).untrackBuddy.call(this, aNick);
}

export var ircMONITOR = {
  name: "MONITOR",
  // Slightly above default IRC priority.
  priority: ircHandlerPriorities.DEFAULT_PRIORITY + 10,
  // Use MONITOR only if MONITOR is enabled and WATCH is not enabled, as WATCH
  // supports more features.
  isEnabled() {
    return this.monitorEnabled && !this.watchEnabled;
  },

  commands: {
    251(aMessage) {
      // RPL_LUSERCLIENT
      // ":There are <integer> users and <integer> services on <integer> servers"
      // Assume that this will always be sent after the 005 handler on
      // connection registration. If MONITOR is enabled, then set the new
      // function to keep track of nicks and send the messages to watch the
      // nicks.

      // Ensure that any new buddies are set to be watched, and removed buddies
      // are no longer watched.
      this.trackBuddy = trackBuddyMonitor;
      this.untrackBuddy = untrackBuddyMonitor;

      // Build the watchlist from the current list of nicks.
      this.trackBuddy(this.trackQueue);

      // Fall through to other handlers since we're only using this as an entry
      // point and not actually handling the message.
      return false;
    },

    303(aMessage) {
      // RPL_ISON
      // :*1<nick> *( " " <nick> )
      // We don't want ircBase to interfere with us, so override the ISON
      // handler to do nothing if we're using MONITOR.
      return true;
    },

    730(aMessage) {
      // RPL_MONONLINE
      // :<server> 730 <nick> :nick!user@host[,nick!user@host]*
      // Mark each nick as online.
      return aMessage.params[1]
        .split(",")
        .map(aNick => setStatus(this, aNick.split("!", 1)[0], "AVAILABLE"))
        .every(aResult => aResult);
    },

    731(aMessage) {
      // RPL_MONOFFLINE
      // :<server> 731 <nick> :nick[,nick1]*
      return aMessage.params[1]
        .split(",")
        .map(aNick => setStatus(this, aNick, "OFFLINE"))
        .every(aResult => aResult);
    },

    732(aMessage) {
      // RPL_MONLIST
      // :<server> 732 <nick> :nick[,nick1]*
      return false;
    },

    733(aMessage) {
      // RPL_ENDOFMONLIST
      // :<server> 733 <nick> :End of MONITOR list
      return false;
    },

    734(aMessage) {
      // ERR_MONLISTFULL
      // :<server> 734 <nick> <limit> <nicks> :Monitor list is full.
      this.ERROR(
        "Maximum size for MONITOR list exceeded (" + this.params[1] + ")."
      );
      return true;
    },
  },
};