/*
 * This file is part of blabouncer (https://www.blatech.co.uk/l_bratch/blabouncer).
 * Copyright (C) 2019 Luke Bratch <luke@bratch.co.uk>.
 *
 * Blabouncer is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3.
 *
 * Blabouncer 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with blabouncer. If not, see <http://www.gnu.org/licenses/>.
*/

#include "logging.h"

// Write the line 'str' to the relevant log file such as
// '#channel.log' or 'nickname.log'.  'ircdstate->ircnick'
// is our own nick and is used to determine which log file
// to write to if the type is LOG_PRIVMSG.
// 'basedir' is the directory in which the 'logs' directory
// will be created in which logs are to be written.
//
// If LOG_PRIVMSG then it expects a string in the format:
// :from!bar@baz PRIVMSG to :hello world
//
// LOG_PRIVMSG is also used for NOTICEs.
//
// If LOG_JOINPART then it expects a string in the format:
// :nick!bar@baz JOIN :#channel
// or
// :nick!bar@baz PART #channel
//
// If LOG_TOPIC then it expects a string in the format:
// :nick!bar@baz TOPIC #channel :bla bla bla
//
// If LOG_NETWORK then it just logs the string verbatim in
// a file named 'ircdstate->ircdname'.log.
//
// If LOG_QUIT then it expects a string in the format:
// channelname :nick!bar@baz QUIT :bla bla bla
// 'channelname' probably has to be prepended manually by the
// caller since it doesn't feature in the raw message from
// the IRCd.  We need it in logline() to log to the relevant
// channel log file.  The caller probably has to call logline()
// multiple times for each channel the nick was in.
//
// If LOG_NICK then it expects a string in the format:
// :oldnick!bar@baz NICK :newnick
// Same manual 'channelname' prepending as LOG_QUIT above.
//
// If LOG_MODE then it expects a string in the format:
// :nick!bar@baz MODE #channel foo bar [foo bar...]
//
// With the ":foo!bar@baz "prefix being important for all
// types.
//
// Returns 1 on success or 0 on failure.
int logline(char *str, struct ircdstate *ircdstate, char *basedir, int type) {
  // Filename to write to, gets built as we go
  char filename[MAXCHAR];

  // Log line to ultimately write, gets built as we go
  char line[MAXCHAR];

  // Variables for LOG_JOINPART (can't define directly inside switch case)
  int pos;

  // Build array of each space-separated token
  char tokens[MAXTOKENS][MAXDATASIZE];
  char *token;

  // Whether or not this is a "/me" PRIVMSG so we can log it slightly differently later
  int meprivmsg = 0;

  // Split out the first three space-separated parts of the string, leaving the rest.
  // If LOG_PRIVMSG:
  // This gets us the prefix (containing the "from" nick), the PRIVMSG command (not needed),
  // and the "to" nick or channel.  Plus the rest of the string intact (which is the actual
  // message).
  // If LOG_JOINPART:
  // This gets us the prefix (containing the joined/parted nick), the JOIN/PART command (not needed),
  // and the channel name.
  // If LOG_TOPIC:
  // This gets us the prefix (containing the topic setting nick), the TOPIC command (not needed),
  // the channel whose topic was set, and the rest of the string intact (which is the new topic).
  // If LOG_NETWORK:
  // Don't do this at all since we want to log the whole string.
  if (type != LOG_NETWORK) {
    for (int i = 0; i < 3; i++) {
      // Try to split
      if ((token = strsep(&str, " ")) == NULL) {
        debugprint(DEBUG_CRIT, "Error splitting string for logging, returning!\n");
        return 0;
      }
      // Copy into the token array (strlen + 1 to get the NULL terminator)
      strncpy(tokens[i], token, strlen(token) + 1);
      debugprint(DEBUG_FULL, "logline(): extracted '%s'.\n", tokens[i]);
    }
  }

  // Make "filename safe" copies of from and to names, as well as ircdstate->ircdname
  // to ensure filename ends up being safe
  char from[MAXCHAR], to[MAXCHAR], ircdname[MAXCHAR];
  strcpy(from, tokens[0]);
  strcpy(to, tokens[2]);
  strcpy(ircdname, ircdstate->ircdname);
  // Remove unsafe characters (assuming POSIX, just strip "/" and replace with "_")
  replacechar(from, '/', '_');
  replacechar(to, '/', '_');
  replacechar(ircdname, '/', '_');
  // Ensure filename wouldn't be too long (+ 4 for ".log")
  if (strlen(from) + 4 > NAME_MAX || strlen(to) + 4 > NAME_MAX || strlen(ircdname) + 4 > NAME_MAX ) {
    debugprint(DEBUG_CRIT, "Filename would be too long if logging either '%s', '%s' or '%s', returning!\n", from, to, ircdname);
    return 0;
  }
  // Make the filename lowercase (since IRC nicks and channel names are case-insensitive,
  // we can ensure a nick/channel with varying case always ends up in the same log file)
  strlower(from);
  strlower(to);
  strlower(ircdname);

  switch(type) {
    case LOG_PRIVMSG:
      // Extract the username from the prefix
      extractnickfromprefix(tokens[0], 1);
      extractnickfromprefix(from, 1);

      // Remove the leading ":" from the real message
      stripprefix(str, 1);

      // Build the log filename
      // If the message was sent to us, then log it in the sender's log file
      if ((strlen(tokens[2]) == strlen(ircdstate->ircnick)) && (strncmp(tokens[2], ircdstate->ircnick, strlen(tokens[2])) == 0)) {
        if (!snprintf(filename, MAXCHAR, "%s/logs/%s.log", basedir, from)) {
          debugprint(DEBUG_CRIT, "Error while preparing log filename for from name, returning!\n");
          return 0;
        }
      } else {
        // Otherwise log it in the "to" log file
        if (!snprintf(filename, MAXCHAR, "%s/logs/%s.log", basedir, to)) {
          debugprint(DEBUG_CRIT, "Error while preparing log filename for to name, returning!\n");
          return 0;
        }
      }

      // If it was a "/me" line then strip the "\1ACTION " and the trailing "\1", plus set a flag for later
      if (strstr(str, "\1ACTION ") == str) {
        debugprint(DEBUG_FULL, "logline(): /me PRIVMSG detected, stripping ACTION things.\n");
        // Skip over the first 8 characters (\1ACTION )
        str += 8;
        // And remove the trailing \1
        if (str[strlen(str) - 1] == '\1') {
          str[strlen(str) - 1] = '\0';
        }
        meprivmsg = 1;
      }

      debugprint(DEBUG_FULL, "logline(): Logging PRIVMSG from '%s' to '%s' message '%s' in filename '%s'.\n", tokens[0], tokens[2], str, filename);

      break;

    case LOG_JOINPART:
      // Find the start of the channel name

      // If it's a JOIN
      if (tokens[2][0] == ':') {
        pos = 1;
      } else if (tokens[2][0] == '#') {
        // Perhaps it's a PART
        pos = 0;
      } else {
        // If not found, return 0
        return 0;
      }

      snprintf(filename, MAXCHAR, "%s/logs/%s.log", basedir, to + pos);

      debugprint(DEBUG_FULL, "logline(): Logging JOIN/PART to/from '%s' in filename '%s'.\n", tokens[2] + pos, filename);

      // Build a friendly message (e.g. ":nick!user@host JOIN #channel" -> "nick (user@host) has joined #channel")

      // Find the bang in the prefix
      char *ret;
      int posbang;
      if ((ret = strstr(tokens[0], "!")) != NULL) {
        // Position within str of "!"
        posbang = ret - tokens[0];
      } else {
        // No idea what happened, let's abandon ship
        return 0;
      }

      // Make it a null character
      tokens[0][posbang] = '\0';

      // Swap JOINed or PARTed for a friendly word
      if (strncmp(tokens[1], "JOIN", strlen("JOIN")) == 0) {
        snprintf(tokens[1], strlen("joined") + 1, "joined");
      } else if (strncmp(tokens[1], "PART", strlen("PART")) == 0) {
        snprintf(tokens[1], strlen("left") + 1, "left");
      }

      // Copy the nick, then user@host, then whether it was a join or part, then the channel name the string to send
      snprintf(line, MAXCHAR, "%s (%s) has %s %s", tokens[0] + 1, tokens[0] + posbang + 1, tokens[1], tokens[2] + pos);

      break;

    case LOG_TOPIC:
      // Extract the username from the prefix
      extractnickfromprefix(tokens[0], 1);

      // Remove the leading ":" from the topic
      stripprefix(str, 1);

      if (!snprintf(filename, MAXCHAR, "%s/logs/%s.log", basedir, to)) {
        debugprint(DEBUG_CRIT, "Error while preparing log filename for topic, returning!\n");
        return 0;
      }

      debugprint(DEBUG_FULL, "logline(): Logging TOPIC for '%s' in filename '%s'.\n", tokens[2], filename);

      // Build a friendly message (e.g. ":nick!user@host TOPIC #channel :blah blah" -> "nick has changed the topic to: blah blah")
      snprintf(line, MAXCHAR, "%s has changed the topic to: %s", tokens[0], str);

      break;

    case LOG_NETWORK:
      // Make sure we actually have an ircdname, if not, don't try to continue
      if (strlen(ircdstate->ircdname) < 1) {
        debugprint(DEBUG_CRIT, "logline(): No ircdname (yet?), returning.\n");
        return 0;
      }

      if (!snprintf(filename, MAXCHAR, "%s/logs/%s.log", basedir, ircdname)) {
        debugprint(DEBUG_CRIT, "Error while preparing log filename for network, returning!\n");
        return 0;
      }

      debugprint(DEBUG_FULL, "logline(): Logging network log for '%s' in filename '%s'.\n", str, filename);

      // Copy source message verbatim to destination
      strcpy(line, str);

      break;

    case LOG_QUIT:
      // Build a friendly message (e.g. "#channel :nick!user@host QUIT :foo bar baz" -> "nick (user@host) has quit (foo bar baz)")

      // Find the bang in the prefix
      // (ret and posbang defined above in case LOG_JOINPART)
      if ((ret = strstr(tokens[1], "!")) != NULL) {
        // Position within str of "!"
        posbang = ret - tokens[1];
      } else {
        // No idea what happened, let's abandon ship
        debugprint(DEBUG_CRIT, "logline(): Unable to find '!' within nick!user@host, returning!\n");
        return 0;
      }

      // Make it a null character
      tokens[1][posbang] = '\0';

      // Strip the prefix from the quit message
      stripprefix(str, 1);

      // Build a friendly message (e.g. "nick (user@host) has quit (Quit: message)")
      snprintf(line, MAXCHAR, "%s (%s) has quit (%s)", tokens[1] + 1, tokens[1] + posbang + 1, str);

      // Build the log filename
      if (!snprintf(filename, MAXCHAR, "%s/logs/%s.log", basedir, from)) {
        debugprint(DEBUG_CRIT, "logline(): Error while preparing log filename for quit, returning!\n");
        return 0;
      }

      break;

    case LOG_NICK:
      // Extract old nick from the prefix
      extractnickfromprefix(tokens[1], 1);
      // Strip colon from new nick
      stripprefix(str, 1);

      // Build a friendly message (e.g. "oldnick is now known as newnick")
      snprintf(line, MAXCHAR, "%s is now known as %s", tokens[1], str);

      // Build the log filename
      if (!snprintf(filename, MAXCHAR, "%s/logs/%s.log", basedir, from)) {
        debugprint(DEBUG_CRIT, "logline(): Error while preparing log filename for nick, returning!\n");
        return 0;
      }

      break;

    case LOG_MODE:
      // Extract nick from prefix
      extractnickfromprefix(tokens[0], 1);

      // Build a friendly message (e.g. "nick sets mode #channel +ov nick1 nick2")
      if (!snprintf(line, MAXCHAR, "%s sets mode %s %s", tokens[0], tokens[2], str)) {
        debugprint(DEBUG_CRIT, "logline(): Error while preparing friendly message for mode log message, returning!\n");
        return 0;
      }

      // Build the log filename
      if (!snprintf(filename, MAXCHAR, "%s/logs/%s.log", basedir, to)) {
        debugprint(DEBUG_CRIT, "logline(): Error while preparing log filename for mode, returning!\n");
        return 0;
      }

      break;

    default :
      debugprint(DEBUG_CRIT, "logline(): Unknown log type '%d', returning 0.\n", type);
      return 0;
  }

  // Make sure the log directory exists
  char logdir[PATH_MAX];
  snprintf(logdir, PATH_MAX, "%s/logs/", basedir);
  struct stat st = {0};
  if (stat(logdir, &st) == -1) {
    if (mkdir(logdir, 0700)) {
      debugprint(DEBUG_CRIT, "Error creating log directory '%s.\n", logdir);
      printf("Error creating log directory '%s'.\n", logdir);
      return 0;
    } else {
      debugprint(DEBUG_FULL, "logline(): log directory '%s'.\n", logdir);
    }
  }

  FILE *fp;

  int bytes = 0;

  fp = fopen(filename, "a");

  if (fp == NULL) {
    debugprint(DEBUG_CRIT, "error: could not open log file '%s' for writing.\n", filename);
    printf("error: could not open log file '%s' for writing.\n", filename);
    fclose(fp);
    return 0;
  }

  // Get a current time string to prepend - TODO - Make this customisable.
  time_t rawtime;
  struct tm * timeinfo;
  time(&rawtime);
  timeinfo = localtime(&rawtime);
  // Strip the trailing newline
  char timestr[MAXCHAR];
  snprintf(timestr, MAXCHAR, "%s", asctime(timeinfo));
  timestr[strlen(timestr) - 1] = '\0';

  if (type == LOG_PRIVMSG) {
    // Prepend the time string and "from" nick, different formatting depending on
    // whether or not it was a "/me" message
    if (meprivmsg) {
      if (!snprintf(line, MAXCHAR, "%s * %s %s", timestr, tokens[0], str)) {
        fprintf(stderr, "Error while preparing /me log string to write!\n");
        debugprint(DEBUG_CRIT, "Error while preparing /me log string to write!\n");
        fclose(fp);
        return 0;
      }
    } else {
      if (!snprintf(line, MAXCHAR, "%s <%s> %s", timestr, tokens[0], str)) {
        fprintf(stderr, "Error while preparing log string to write!\n");
        debugprint(DEBUG_CRIT, "Error while preparing log string to write!\n");
        fclose(fp);
        return 0;
      }
    }
  } else if (type == LOG_JOINPART || type == LOG_TOPIC || type == LOG_NETWORK ||
             type == LOG_QUIT || type == LOG_NICK || type == LOG_MODE) {
    // Prepend the time string
    char line2[MAXCHAR];
    if (!snprintf(line2, MAXCHAR, "%s %s", timestr, line)) {
      fprintf(stderr, "Error while preparing log string to write!\n");
      debugprint(DEBUG_CRIT, "Error while preparing log string to write!\n");
      fclose(fp);
      return 0;
    }
    // Copy back to line to write
    snprintf(line, MAXCHAR, "%s", line2);
  }

  // Ensure the line finishes with CRLF
  appendcrlf(line);

  debugprint(DEBUG_FULL, "logline(): Complete log string to write: '%s' to '%s', length '%ld'.\n", line, filename, strlen(line));

  // Write complete line to file
  if ((bytes = fprintf(fp, "%s", line)) < 0) {
    printf("error: could not write to log file.\n");
    debugprint(DEBUG_CRIT, "error: could not write to log file.\n");
    fclose(fp);
    return 0;
  }

  fclose(fp);
  return bytes;
}