/*

 * histolog.c   -- File history handling

 *

 * Copyright (C) 2005-2015 Mikael Berthe <mikael@lilotux.net>

 *

 * This program 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; either version 2 of the License, or (at

 * your option) any later version.

 *

 * This program 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 this program; if not, see <http://www.gnu.org/licenses/>.

 */

#include <ctype.h>

#include <errno.h>

#include <fcntl.h>

#include <stdlib.h>

#include <string.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <time.h>

#include <unistd.h>

#include "histolog.h"

#include "hbuf.h"

#include "utils.h"

#include "screen.h"

#include "settings.h"

#include "utils.h"

#include "roster.h"

#include "xmpp.h"

static guint UseFileLogging;

static guint FileLoadLogs;

static char *RootDir;

//  user_histo_file(jid)

// Returns history filename for the given jid

// Note: the caller *must* free the filename after use (if not null).

static char *user_histo_file(const char *bjid)

{

  char *filename;

  char *lowerid;

  if (!(UseFileLogging || FileLoadLogs))

    return NULL;

  if (!g_strcmp0(bjid, ".") || !g_strcmp0(bjid, "..") ||

      strchr(bjid, '/'))

    return NULL;

  lowerid = g_strdup(bjid);

  if (!lowerid)

    return NULL;

  mc_strtolower(lowerid);

  filename = g_strdup_printf("%s%s", RootDir, lowerid);

  g_free(lowerid);

  return filename;

}

//  hlog_get_log_jid(bare_jid)

// Returns the real JID used for a symlinked history log file,

// or NULL if there's no symbolic link.

char *hlog_get_log_jid(const char *bjid)

{

  struct stat bufstat;

  char *path;

  char *log_jid = NULL;

  path = user_histo_file(bjid);

  while (path) {

    if (lstat(path, &bufstat) != 0)

      break;

    if (S_ISLNK(bufstat.st_mode)) {

      g_free(log_jid);

      log_jid = g_new0(char, bufstat.st_size+1);

      if (readlink(path, log_jid, bufstat.st_size) < 0) return NULL;

      g_free(path);

      path = user_histo_file(log_jid);

    } else {

      break;

    }

  }

  g_free(path);

  return log_jid;

}

//  write_histo_line()

// Adds a history (multi-)line to the jid's history logfile

static void write_histo_line(const char *bjid,

        time_t timestamp, guchar type, guchar info, const char *data)

{

  guint len = 0;

  FILE *fp;

  time_t ts;

  const char *p;

  char *filename;

  char str_ts[20];

  int err;

  if (!UseFileLogging)

    return;

  // Do not log status messages when 'logging_ignore_status' is set

  if (type == 'S' && settings_opt_get_int("logging_ignore_status"))

    return;

  filename = user_histo_file(bjid);

  // If timestamp is null, get current date

  if (timestamp)

    ts = timestamp;

  else

    time(&ts);

  if (!data)

    data = "";

  // Count number of extra lines

  for (p=data ; *p ; p++)

    if (*p == '\n') len++;

  /* Line format: "TI yyyymmddThh:mm:ssZ LLL [data]"

   * T=Type, I=Info, yyyymmddThh:mm:ssZ=date, LLL=0-padded-len

   *

   * Types:

   * - M message    Info: S (send) R (receive) I (info)

   * - S status     Info: [_ofdnai]

   * We don't check them, we trust the caller.

   * (Info messages are not sent nor received, they're generated

   * locally by mcabber.)

   */

  fp = fopen(filename, "a");

  g_free(filename);

  if (!fp) {

    scr_LogPrint(LPRINT_LOGNORM, "Unable to write history "

                 "(cannot open logfile)");

    return;

  }

  to_iso8601(str_ts, ts);

  err = fprintf(fp, "%c%c %-18.18s %03d %s\n", type, info, str_ts, len, data);

  fclose(fp);

  if (err < 0) {

    scr_LogPrint(LPRINT_LOGNORM, "Error while writing to log file: %s",

                 strerror(errno));

  }

}

//  hlog_read_history()

// Reads the jid's history logfile

void hlog_read_history(const char *bjid, GList **p_buddyhbuf, guint width)

{

  char *filename;

  guchar type, info;

  char *data, *tail;

  guint data_size;

  char *xtext;

  time_t timestamp;

  guint prefix_flags;

  guint len;

  FILE *fp;

  struct stat bufstat;

  guint err = 0;

  guint ln = 0; // line number

  time_t starttime;

  int max_num_of_blocks;

  if (!FileLoadLogs)

    return;

  if ((roster_gettype(bjid) & ROSTER_TYPE_ROOM) &&

      (settings_opt_get_int("load_muc_logs") != 1))

    return;

  data_size = HBB_BLOCKSIZE+32;

  data = g_new(char, data_size);

  if (!data) {

    scr_LogPrint(LPRINT_LOGNORM, "Not enough memory to read history file");

    return;

  }

  filename = user_histo_file(bjid);

  fp = fopen(filename, "r");

  g_free(filename);

  if (!fp) {

    g_free(data);

    return;

  }

  // If file is large (> 3MB here), display a message to inform the user

  // (it can take a while...)

  if (!fstat(fileno(fp), &bufstat)) {

    if (bufstat.st_size > 3145728) {

      scr_LogPrint(LPRINT_NORMAL, "Reading <%s> history file...", bjid);

      scr_do_update();

    }

  }

  max_num_of_blocks = get_max_history_blocks();

  starttime = 0L;

  if (settings_opt_get_int("max_history_age") > 0) {

    int maxdays = settings_opt_get_int("max_history_age");

    time(&starttime);

    if (maxdays >= starttime/86400L)

      starttime = 0L;

    else

      starttime -= maxdays * 86400L;

  }

  /* See write_histo_line() for line format... */

  while (!feof(fp)) {

    guint dataoffset = 25;

    guint noeol;

    if (fgets(data, data_size-1, fp) == NULL)

      break;

    ln++;

    tail = data;

    while (!feof(fp)) {

      for (tail = data; *tail; tail++) ;

      if (tail == data) {

        // That would happen if the log file has NUL characters...

        scr_LogPrint(LPRINT_LOGNORM, "Corrupted history file!  Trying to recover.");

        err = 1;

        break;

      }

      noeol = (*(tail-1) != '\n');

      if (!noeol)

        break;

      /* TODO: duplicated code... could do better... */

      if (tail == data + data_size-2) {

        // The buffer is too small to contain the whole line.

        // Let's allocate some more space.

        if (!max_num_of_blocks ||

            data_size/HBB_BLOCKSIZE < 5U*max_num_of_blocks) {

          guint toffset = tail - data;

          // Allocate one more block.

          data_size = HBB_BLOCKSIZE * (1 + data_size/HBB_BLOCKSIZE);

          data = g_renew(char, data, data_size);

          // Update the tail pointer, as the data may have been moved.

          tail = data + toffset;

          if (fgets(tail, data_size-1 - (tail-data), fp) == NULL)

            break;

        } else {

          scr_LogPrint(LPRINT_LOGNORM, "Line too long in history file!");

          ln--;

          break;

        }

      }

    }

    type = data[0];

    info = data[1];

    if ((type != 'M' && type != 'S') ||

        ((data[11] != 'T') || (data[20] != 'Z') ||

         (data[21] != ' ') ||

         (data[25] != ' ' && data[26] != ' '))) {

      if (!err) {

        scr_LogPrint(LPRINT_LOGNORM,

                     "Error in history file format (%s), l.%u", bjid, ln);

        err = 1;

      }

      continue;

    }

    // The number of lines can be written with 3 or 4 bytes.

    if (data[25] != ' ') dataoffset = 26;

    data[21] = data[dataoffset] = 0;

    timestamp = from_iso8601(&data[3], 1);

    len = (guint) atoi(&data[22]);

    // Some checks

    if (((type == 'M') && (info != 'S' && info != 'R' && info != 'I')) ||

        ((type == 'S') && (!strchr("_OFDNAI", info)))) {

      if (!err) {

        scr_LogPrint(LPRINT_LOGNORM, "Error in history file format (%s), l.%u",

                     bjid, ln);

        err = 1;

      }

      continue;

    }

    while (len--) {

      ln++;

      if (fgets(tail, data_size-1 - (tail-data), fp) == NULL)

        break;

      while (*tail) tail++;

      noeol = (*(tail-1) != '\n');

      if (tail == data + data_size-2 && (len || noeol)) {

        // The buffer is too small to contain the whole message.

        // Let's allocate some more space.

        if (!max_num_of_blocks ||

            data_size/HBB_BLOCKSIZE < 5U*max_num_of_blocks) {

          guint toffset = tail - data;

          // If the line hasn't been read completely and we reallocate the

          // buffer, we want to read one more time.

          if (noeol)

            len++;

          // Allocate one more block.

          data_size = HBB_BLOCKSIZE * (1 + data_size/HBB_BLOCKSIZE);

          data = g_renew(char, data, data_size);

          // Update the tail pointer, as the data may have been moved.

          tail = data + toffset;

        } else {

          // There will probably be a parse error on next read, because

          // this message hasn't been read entirely.

          scr_LogPrint(LPRINT_LOGNORM, "Message too big in history file!");

        }

      }

    }

    // Remove last CR (we keep it if the line is empty, too)

    if ((tail > data+dataoffset+1) && (*(tail-1) == '\n'))

      *(tail-1) = 0;

    // Check if the data is older than max_history_age

    if (starttime) {

      if (timestamp > starttime)

        starttime = 0L; // From now on, load everything

      else

        continue;

    }

    if (type == 'M') {

      char *converted;

      if (info == 'S') {

        prefix_flags = HBB_PREFIX_OUT | HBB_PREFIX_HLIGHT_OUT;

      } else {

        prefix_flags = HBB_PREFIX_IN;

        if (info == 'I')

          prefix_flags = HBB_PREFIX_INFO;

      }

      converted = from_utf8(&data[dataoffset+1]);

      if (converted) {

        xtext = ut_expand_tabs(converted); // Expand tabs

        hbuf_add_line(p_buddyhbuf, xtext, timestamp, prefix_flags, width,

                      max_num_of_blocks, 0, NULL);

        if (xtext != converted)

          g_free(xtext);

        g_free(converted);

      }

      err = 0;

    }

  }

  fclose(fp);

  g_free(data);

}

//  hlog_enable()

// Enable logging to files.  If root_dir is NULL, then the subdirectory "histo"

// in mcabber configuration directory is used.

// If loadfiles is TRUE, we will try to load buddies history logs from file.

void hlog_enable(guint enable, const char *root_dir, guint loadfiles)

{

  UseFileLogging = enable;

  FileLoadLogs = loadfiles;

  g_free(RootDir);

  RootDir = NULL;

  if (!enable && !loadfiles)

    return;

  if (root_dir) {

    char *xp_root_dir;

    int l = strlen(root_dir);

    if (l < 1) {

      scr_LogPrint(LPRINT_LOGNORM, "Error: logging dir name too short");

      UseFileLogging = FileLoadLogs = FALSE;

      return;

    }

    xp_root_dir = expand_filename(root_dir);

    // RootDir must be slash-terminated

    if (root_dir[l-1] == '/') {