/*
 * 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 "config.h"

// Sets 'dest' to the value of the configuration option with name
// 'confname' from configuration file 'filename'.
// Returns 1 for success or 0 for error/failure.
int getconfstr(char *confname, char *filename, char* dest) {
  FILE *fp;
  char str[MAXCHAR];
  int found = 0; // Have we found the configuration option?

  // Set string to zero-length to begin
  dest[0] = '\0';

  // Length of requested configuration option name
  long int namelen = strlen(confname);

  fp = fopen(filename, "r");

  if (fp == NULL) {
    printf("error: could not open configuration file '%s'.\n", filename);
    debugprint(DEBUG_CRIT, "error: could not open configuration file '%s'.\n", filename);
    exit(1);
  }
  // Loop through the whole file, looking for the requested configuration option
  while (fgets(str, MAXCHAR, fp) != NULL) {
    char substr[MAXCHAR];

    // Check if the next character after the length of the requested option
    // name is an equals sign, a space, or a tab
    if (str[namelen] != '=' && str[namelen] != ' ' && str[namelen] != '\t') {
      // If it isn't this can't have been our option
      continue;
    }

    // Copy the number of characters that the requested option name is long
    // to a temporary string
    strncpy(substr, str, namelen);
    substr[namelen] = '\0';

    // If the resulting temporary string contains the requested option name,
    // we have found our configuration option and it is in the current 'str'
    if (strstr(substr, confname)) {
      found = 1;
      break;
    }
  }

  // If we got here, then either we found the configuration option or we ran out of file

  if (!found) {
    debugprint(DEBUG_SOME, "Error reading configuration option '%s', did not find it in configuration file '%s'.\n", confname, filename);
    fclose(fp);
    return 0;
  }

  long int pos = 0;
  char conf[MAXCHAR]; // Temporary string to build configuration value in

  // Starting from the end of the option name, find the position of the start of the configuration value
  // (including its double quotes) by skipping over everything that isn't an equals sign, a space, or a tab
  for (size_t i = namelen; i < strlen(str); i++) {
    if (str[i] == '=' || str[i] == ' ' || str[i] == '\t') {
      continue;
    } else {
      // Record current/final position in string
      pos = i;
      break;
    }
  }

  strncpy(conf, str + pos, strlen(str) - pos - 1); // Copy remainder to new string and lop off the newline
  conf[strlen(str) - pos - 1] = '\0'; // Null terminate

   // Check for start and end quotes
  if (conf[0] != '"' || conf[strlen(conf) - 1] != '"') {
    printf("Error reading configuration option '%s', not enclosed in double quotes in configuration file '%s'!\n", confname, filename);
    debugprint(DEBUG_CRIT, "Error reading configuration option '%s', not enclosed in double quotes in configuration file '%s'!\n", confname, filename);
    exit(1);
  }

  strncpy(dest, conf + 1, strlen(conf) - 2); // Copy result to destination string without quotes
  dest[strlen(conf) - 2] = '\0'; // Null terminate

  debugprint(DEBUG_FULL, "getconfstr(): returning '%s'.\n", dest);

  // Close fine and return success
  fclose(fp);
  return 1;
}

// Populates 'dest' with the values of the configuration array option
// with name 'confname' from configuration file 'filename'.
// Returns 1 on success, 0 on reading no values, or -1 on an error.
// On error, dest[0] is set to the error string for later retrieval.
int getconfarr(char *confname, char *filename, char dest[MAXCONFARR][MAXDATASIZE]) {
  debugprint(DEBUG_FULL, "getconfarr(): '%s', '%s' and a dest array.\n", confname, filename);

  FILE *fp;
  char line[MAXCHAR];
  int found = 0; // Have we found the configuration option?
  int valuecount = 0; // Which element in the configuration array we are on

  // Set strings to zero-length to begin
  for (int i = 0; i < MAXCONFARR; i++) {
    dest[i][0] = '\0';
  }

  // Length of requested configuration array name
  long int namelen = strlen(confname);

  fp = fopen(filename, "r");

  if (fp == NULL) {
    debugprint(DEBUG_CRIT, "error: could not open configuration file '%s'.\n", filename);
    exit(1);
  }
  // Loop through the whole file, looking for the requested configuration array
  while (fgets(line, MAXCHAR, fp) != NULL) {
    // Don't bother with any of this if this line is a comment
    int comment = 0;
    for (size_t i = 0; i < strlen(line); i++) {
      // Ignore spaces/tabs
      if (line[i] == ' ' || line[i] == '\t') {
        continue;
      } else if (line[i] == '#') {
        // If it's a comment, ignore the line
        comment = 1;
        break;
      } else {
        // Found something else before a comment, so carry on
        break;
      }
    }

    if (comment) {
      continue;
    }

    // If we haven't found our array yet, try to find the opening line
    if (!found) {
      char substr[MAXCHAR];

      // Check if the next character after the length of the requested array
      // name is an equals sign, a space, or a tab
      if (line[namelen] != '=' && line[namelen] != ' ' && line[namelen] != '\t') {
        // If it isn't this can't have been our array
        continue;
      }

      // Copy the number of characters that the requested array name is long
      // to a temporary string
      strncpy(substr, line, namelen);
      substr[namelen] = '\0';

      // If the resulting temporary string contains the requested array name,
      // we have found our configuration array
      if (strstr(substr, confname)) {
        // Make sure it is a valid start of array line
        for (size_t i = namelen; i < strlen(line); i++) {
          if (line[i] == ' ' || line[i] == '\t' || line[i] == '=') {
            // Ignore spaces, tabs and equals signs
            continue;
          } else if (line[i] == '{') {
            // Success, found an opening brace
            // Ignore anything else on this line
            found = 1;
            break;
          } else {
            // Unexpected character found, return failure
            snprintf(dest[0], MAXDATASIZE, "Unexpected character '%c' found on configuration array opening line for '%s'.\n", line[i], confname);
            fclose(fp);
            return -1;
          }
        }
      }
    // If we have found our array, extract the value from each line in it
    } else {
      int valuelen = 0;
      int inquotes = 0;
      for (size_t i = 0; i < strlen(line); i++) {
        // If we've on the closing brace line, then we're done
        if (line[i] == '}') {
          for (int i = 0; i < valuecount; i++) {
            debugprint(DEBUG_FULL, "getconfarr(): returning '%s'.\n", dest[i]);
          }

          // Close fine and return success (or 0 if no values found in an otherwise valid array)
          fclose(fp);
          if (valuecount) {
            return 1;
          } else {
            return 0;
          }
        }

        // If not in the quotes yet
        if (!inquotes) {
          // Skip over initial spaces and tabs
          if (line[i] == ' ' || line[i] == '\t') {
            continue;
          } else if (line[i] == '"') {
            // Quotes found, we're now reading the value
            inquotes = 1;
            continue;
          } else {
            // Unexpected character found, return failure
            snprintf(dest[0], MAXDATASIZE, "Unexpected character '%c' found before opening quotes on array line for '%s'.\n", line[i], confname);
            fclose(fp);
            return -1;
          }
          // If inside the quotes (so, we've got to the actual value)
        } else if (inquotes) {
          // If we're on the last character and it isn't a closing quote, something is wrong
          if (i == strlen(line) - 1 && line[i] != '"') {
            snprintf(dest[0], MAXDATASIZE, "Reached end of line without finding closing quotes on array line for '%s'.\n", confname);
            fclose(fp);
            return -1;
          }

          // If we've found too many values, return an error
          if (valuecount > MAXCONFARR - 1) {
            snprintf(dest[0], MAXDATASIZE, "Too many elements defined for configuration array '%s', maximum number is '%d'.\n", confname, MAXCONFARR);
            fclose(fp);
            return -1;
          }

          // Otherwise, copy everything that isn't the closing quotes to the current element in the dest array
          if (line[i] != '"') {
            dest[valuecount][valuelen] = line[i];
            valuelen++;
            continue;
          } else {
            // When we find the closing quotes, the value is read, so terminate the dest array element string
            dest[valuecount][valuelen] = '\0';
            // We're done with this value, ignore anything that may be after the closing quotes on this line
            valuecount++;
            break;
          }
        }
      }
    }
  }

  // If we get this far, then something went wrong
  snprintf(dest[0], MAXDATASIZE, "getconfarr(): didn't find any configuration array for '%s'.\n", confname);
  fclose(fp);
  return 0;
}

// Returns the value of the configuration option with name
// 'confname' from configuration file 'filename'.
// Sets errno to 0 on success, or ECONFINT if it fails, in which case the return value is undefined.
int getconfint(char *confname, char *filename) {
  errno = 0;
  char result[MAXCHAR];
  if (!getconfstr(confname, filename, result)) {
    debugprint(DEBUG_CRIT, "getconfint(): error getting configuration option '%s' from configuration file '%s'.\n", confname, filename);
    errno = ECONFINT;
  }

  return strtol(result, NULL, 10); // Convert resulting string to an integer, base 10
}

// Create the default configuration file.
// Return 1 on success, 0 on failure.
int createconfigfile(char *filename) {
  char *dirtmp;
  char *dir;
  dirtmp = strdup(filename);
  dir = strdup(dirname(dirtmp));

  // Make sure the parent directory exists
  struct stat st = {0};
  if (stat(dir, &st) == -1) {
    if (mkdir(dir, 0700)) {
      printf("Error creating config directory '%s'.\n", dir);
      debugprint(DEBUG_CRIT, "Error creating config directory '%s'.\n", dir);
      exit(1);
    } else {
      printf("Created config directory '%s'.\n", dir);
    }
  }

  FILE *fp;

  fp = fopen(filename, "a");

  if (fp == NULL) {
    printf("error: could not open default configuration file '%s' for writing.\n", filename);
    debugprint(DEBUG_CRIT, "error: could not open default configuration file '%s' for writing.\n", filename);
    exit(1);
  }

  // Prepare the string
  char *string =
  "# blabouncer configuration file\n"
  "#\n"
  "# Normal entries must be in the form:\n"
  "# option name, space, equals sign, space, double quote, option value, double quote\n"
  "# e.g.\n"
  "# realname = \"Mr Bla Bouncer\"\n"
  "#\n"
  "# Array entries must be in the form:\n"
  "# option name, space, equals sign, space, open brace\n"
  "# (optional indentation,) double quote, element value, double quoute\n"
  "# (optional multiple values to be repeated after the first one(s))\n"
  "# close brace\n"
  "# e.g.\n"
  "# connectcommands = {\n"
  "#   \"PRIVMSG NickServ IDENTIFY bananas\"\n"
  "#   \"PRIVMSG myfriend I'm online!\"\n"
  "# }\n"
  "#\n"
  "# Shell expansion is not supported, so do not try and specify e.g.\n"
  "# \"~/.blabouncer/\" or \"$HOME/.blabouncer/\", instead use \"/home/foo/.blabouncer\"\n"
  "#\n"
  "# Some settings can be reloaded at runtime, please refer to README for details.\n"
  "\n"
  "# Nick(s) to use when connecting - will be cycled through in order in the event of\n"
  "# a nick being in use or invalid\n"
  "nicks = {\n"
  "  \"blabounce\"\n"
  "  \"bbounce2\"\n"
  "  \"bbounce3\"\n"
  "}\n"
  "\n"
  "username = \"bounceusr\"\n"
  "realname = \"Mr Bla Bouncer\"\n"
  "\n"
  "# Channels to automatically join (defaults to none)\n"
  "# Put channel keys/passwords after channel names (separated with a space)\n"
  "channels = {\n"
  "  \"#blabouncer keyword\"\n"
  "  \"#test\"\n"
  "}\n"
  "\n"
  "# Auto replay mode upon a bouncer client connecting\n"
  "# \"none\" = Don't auto replay\n"
  "# \"time\" = Always send the last \"replayseconds\" worth of logs\n"
  "# \"lastspoke\" = All messages since your current nick last spoke\n"
  "# \"noclients\" = All messages since you last had no clients connected\n"
  "# \"lastchange\" = All messages since your last client connection/disconnection\n"
  "# \"perclient\" = All messages since the current client last disconnected (see README)\n"
  "replaymode = \"time\"\n"
  "\n"
  "# How many seconds of replay log should be sent to connecting clients if replaymode = \"time\"\n"
  "replayseconds = \"600\"\n"
  "\n"
  "# Should replay log timestamps include the date when replaying? (\"1\" for yes or \"0\" for no)\n"
  "replaydates = \"0\"\n"
  "\n"
  "# Connect password clients must provided to connect\n"
  "password = \"bananas\"\n"
  "\n"
  "# Port the bouncer should listen on\n"
  "clientport = \"1234\"\n"
  "\n"
  "# Enable TLS for clients connecting to the bouncer (\"1\" for yes or \"0\" for no)\n"
  "# If \"0\" then certfile and keyfile need not be set\n"
  "clienttls = \"1\"\n"
  "\n"
  "# Enable TLS for the bouncer connecting to the IRC server (\"1\" for yes or \"0\" for no)\n"
  "servertls = \"1\"\n"
  "\n"
  "# Real IRC server the bouncer connects to\n"
  "ircserver = \"irc.blatech.net\"\n"
  "\n"
  "# Real IRC server port\n"
  "ircserverport = \"6697\"\n"
  "\n"
  "# Real IRC server password\n"
  "#ircserverpassword = \"apples\"\n"
  "\n"
  "# Command(s) to send to the server upon completing registration (e.g. a NickServ password)\n"
  "#connectcommands = {\n"
  "#  \"PRIVMSG NickServ IDENTIFY bananas\"\n"
  "#  \"PRIVMSG myfriend I'm online!\"\n"
  "#}\n"
  "\n"
  "# Base directory (defaults to $HOME/.blabouncer/)\n"
  "# Things such as the logs directory will be placed below this\n"
  "#basedir = \"/home/foo/.blabouncer/\"\n"
  "\n"
  "# Certificate file (defaults to <basedir>/cert.pem)\n"
  "# If clienttls = \"0\" then this need not be set\n"
  "#certfile = \"/home/foo/.blabouncer/cert.pem\"\n"
  "\n"
  "# Certificate key file (defaults to <basedir>/key.pem)\n"
  "# If clienttls = \"0\" then this need not be set\n"
  "#keyfile = \"/home/foo/.blabouncer/key.pem\"\n"
  "\n"
  "# Enable logging (\"1\" for yes or \"0\" for no)\n"
  "# Logs go to basedir/logs/ with one file per channel/nick\n"
  "logging = \"1\"\n"
  "\n"
  "# Enable replay logging (\"1\" for yes or \"0\" for no)\n"
  "# Replay log goes to basedir/replay.log\n"
  "replaylogging = \"1\"\n"
  "\n"
  "# Debug verbosity (\"0\" for critical only, \"1\" for some extra info, \"2\" for full debug mode)\n"
  "# (All output goes to <basedir>/debug.txt)\n"
  "debug = \"2\"\n"
  "\n"
  "# Number of debug logs to keep\n"
  "debugkeep = \"5\"\n";

  // Write complete string to file
  if ((fprintf(fp, "%s", string)) < 0) {
    debugprint(DEBUG_CRIT, "error: could not write to replay log file.\n");
  }

  fclose(fp);
  free(dirtmp);
  free(dir);
  return 0;
}