/*
 *
 * Conky, a system monitor, based on torsmo
 *
 * Any original torsmo code is licensed under the BSD license
 *
 * All code written since the fork of torsmo is licensed under the GPL
 *
 * Please see COPYING for details
 *
 * Copyright (c) 2004, Hannu Saransaari and Lauri Hakkarainen
 * Copyright (c) 2005-2021 Brenden Matthews, Philip Kovacs, et. al.
 *	(see AUTHORS)
 * All rights reserved.
 *
 * 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 3 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 "config.h"

#include "timeinfo.h"

#include <cerrno>
#include <clocale>
#include <cstring>
#include <ctime>
#include "conky.h"
#include "logging.h"
#include "text_object.h"

#include <memory>

struct tztime_s {
  char *tz;  /* timezone variable */
  char *fmt; /* time display formatting */
};

conky::simple_config_setting<bool> times_in_seconds("times_in_seconds", false,
                                                    false);

void scan_time(struct text_object *obj, const char *arg) {
  obj->data.opaque =
      strndup(arg != nullptr ? arg : "%F %T", text_buffer_size.get(*state));
}

void scan_tztime(struct text_object *obj, const char *arg) {
  char buf1[256], buf2[256], *fmt, *tz;
  struct tztime_s *ts;

  fmt = tz = nullptr;
  if (arg != nullptr) {
    int nArgs = sscanf(arg, "%255s %255[^\n]", buf1, buf2);

    if (nArgs == 2) {
      fmt = buf2;
      tz = buf1;
    } else if (nArgs == 1) {
      tz = buf1;
    }
  }

  ts = static_cast<tztime_s *>(malloc(sizeof(struct tztime_s)));
  memset(ts, 0, sizeof(struct tztime_s));
  ts->fmt =
      strndup(fmt != nullptr ? fmt : "%F %T", text_buffer_size.get(*state));
  ts->tz = tz != nullptr ? strndup(tz, text_buffer_size.get(*state)) : nullptr;
  obj->data.opaque = ts;
}

void print_time(struct text_object *obj, char *p, unsigned int p_max_size) {
  time_t t = time(nullptr);
  struct tm *tm = localtime(&t);

  setlocale(LC_TIME, "");
  strftime(p, p_max_size, static_cast<char *>(obj->data.opaque), tm);
}

void print_utime(struct text_object *obj, char *p, unsigned int p_max_size) {
  time_t t = time(nullptr);
  struct tm *tm = gmtime(&t);

  setlocale(LC_TIME, "");
  strftime(p, p_max_size, static_cast<char *>(obj->data.opaque), tm);
}

void print_tztime(struct text_object *obj, char *p, unsigned int p_max_size) {
  char *oldTZ = nullptr;
  time_t t;
  struct tm *tm;
  auto *ts = static_cast<tztime_s *>(obj->data.opaque);

  if (ts == nullptr) { return; }

  if (ts->tz != nullptr) {
    oldTZ = getenv("TZ");
    setenv("TZ", ts->tz, 1);
    tzset();
  }
  t = time(nullptr);
  tm = localtime(&t);

  setlocale(LC_TIME, "");
  strftime(p, p_max_size, ts->fmt, tm);
  if (oldTZ != nullptr) {
    setenv("TZ", oldTZ, 1);
    tzset();
  } else {
    unsetenv("TZ");
  }
  // Needless to free oldTZ since getenv gives ptr to static data
}

void free_time(struct text_object *obj) { free_and_zero(obj->data.opaque); }

void free_tztime(struct text_object *obj) {
  auto *ts = static_cast<tztime_s *>(obj->data.opaque);

  if (ts == nullptr) { return; }

  free_and_zero(ts->tz);
  free_and_zero(ts->fmt);

  free_and_zero(obj->data.opaque);
}

/* a safer asprintf()
 * - no need to check for errors
 * - exit conky on memory allocation failure
 * - XXX: no return value at all, otherwise this
 *        could be used globally */
#define safe_asprintf(bufp, ...)                                   \
  {                                                                \
    int __v;                                                       \
    if ((__v = asprintf(bufp, __VA_ARGS__)) == -1) {               \
      fprintf(stderr, "%s: memory allocation failed\n", __func__); \
      exit(__v);                                                   \
    }                                                              \
  }

// all chars after the ending " and between the seconds and the starting " are
// silently ignored, this is wanted behavior, not a bug, so don't "fix" this.
static void do_format_time(struct text_object *obj, char *p,
                           unsigned int p_max_size) {
  double seconds;
  char *currentchar, *temp;
  unsigned int output_length = 0;
  int minutes, hours, days, weeks;
  char show_minutes = 0, show_hours = 0, show_days = 0, show_weeks = 0,
       hidestring;

  if (!times_in_seconds.get(*state)) {
    NORM_ERR("Enable \"times_in_seconds\" to use $format_time");
    return;
  }

  errno = 0;
  seconds = strtod(obj->data.s, &currentchar);
  if (errno == 0 && obj->data.s != currentchar) {
    while (*currentchar != 0 && *currentchar != '"') { currentchar++; }
    if (*currentchar != 0) {
      currentchar++;
      minutes = seconds / 60;
      seconds -= minutes * 60;
      hours = minutes / 60;
      minutes %= 60;
      days = hours / 24;
      hours %= 24;
      weeks = days / 7;
      days %= 7;
      for (temp = currentchar; *temp != 0 && *temp != '"'; temp++) {
        if (*temp == '\\') {
          switch (*(temp + 1)) {
            case '\\':
              temp++;
              break;
            case 'w':
              show_weeks = 1;
              break;
            case 'd':
              show_days = 1;
              break;
            case 'h':
              show_hours = 1;
              break;
            case 'm':
              show_minutes = 1;
              break;
          }
        }
      }
      if (show_weeks == 0) { days += weeks * 7; }
      if (show_days == 0) { hours += days * 24; }
      if (show_hours == 0) { minutes += hours * 60; }
      if (show_minutes == 0) { seconds += minutes * 60; }
      hidestring = 0;
      while (output_length < p_max_size - 1) {
        if (*currentchar != 0 && *currentchar != '"') {
          temp = nullptr;
          if (*currentchar == '\\' && hidestring == 0) {
            currentchar++;
            switch (*currentchar) {
              case 'w':
                safe_asprintf(&temp, "%d", weeks);
                break;
              case 'd':
                safe_asprintf(&temp, "%d", days);
                break;
              case 'h':
                safe_asprintf(&temp, "%d", hours);
                break;
              case 'm':
                safe_asprintf(&temp, "%d", minutes);
                break;
              case 's':
                safe_asprintf(&temp, "%d", (int)seconds);
                break;
              case 'S':
                currentchar++;
                if (*currentchar >= '0' && *currentchar <= '9') {
                  safe_asprintf(&temp, "%.*f", (*currentchar) - '0', seconds);
                } else if (*currentchar == 'x') {
                  if (seconds == static_cast<int>(seconds)) {
                    safe_asprintf(&temp, "%d", (int)seconds);
                  } else {
                    safe_asprintf(&temp, "%.9f", seconds);
                    while (*(temp + strlen(temp) - 1) == '0' ||
                           *(temp + strlen(temp) - 1) == '.') {
                      *(temp + strlen(temp) - 1) = 0;
                    }
                  }
                } else {
                  currentchar--;
                  NORM_ERR(
                      "$format_time needs a digit behind 'S' to specify "
                      "precision");
                }
                break;
              case '\\':
              case '(':
              case ')':
                p[output_length] = *currentchar;
                output_length++;
                break;
              default:
                NORM_ERR("$format_time doesn't have a special char '%c'",
                         *currentchar);
            }
          } else if (*currentchar == '(') {
            for (temp = currentchar + 1; *temp != 0 && *temp != ')'; temp++) {
              if (*(temp - 1) == '\\') {
                switch (*temp) {
                  case 'w':
                    if (weeks == 0) { hidestring = 1; }
                    break;
                  case 'd':
                    if (days == 0) { hidestring = 1; }
                    break;
                  case 'h':
                    if (hours == 0) { hidestring = 1; }
                    break;
                  case 'm':
                    if (minutes == 0) { hidestring = 1; }
                    break;
                  case 's':
                  case 'S':
                    if (seconds == 0) { hidestring = 1; }
                    break;
                }
              }
            }
            temp = nullptr;
          } else if (*currentchar == ')') {
            hidestring = 0;
          } else if (hidestring == 0) {
            p[output_length] = *currentchar;
            output_length++;
          }
          if (temp != nullptr) {
            if (output_length + strlen(temp) < p_max_size - 1) {
              strncpy(p + output_length, temp,
                      p_max_size - output_length + strlen(temp));
              output_length += strlen(temp);
            } else {
              NORM_ERR("The format string for $format_time is too long");
            }
            free(temp);
          }
          currentchar++;
        } else {
          break;
        }
      }
      p[output_length] = 0;
    } else {
      NORM_ERR(
          "$format_time needs a output-format starting with a \"-char as 2nd "
          "argument");
    }
  } else {
    NORM_ERR("$format_time didn't receive a time in seconds as first argument");
  }
}

void print_format_time(struct text_object *obj, char *p,
                       unsigned int p_max_size) {
  std::unique_ptr<char[]> buf(new char[max_user_text.get(*state)]);

  generate_text_internal(buf.get(), max_user_text.get(*state), *obj->sub);
  obj->data.s = buf.get();
  do_format_time(obj, p, p_max_size);
}
