/**
 * collectd - src/thermal.c
 * Copyright (C) 2008  Michał Mirosław
 *
 * 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; only version 2 of the License is applicable.
 *
 * 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 *
 * Authors:
 *   Michał Mirosław <mirq-linux at rere.qmqm.pl>
 **/

#include "collectd.h"

#include "plugin.h"
#include "utils/common/common.h"
#include "utils/ignorelist/ignorelist.h"

#if !KERNEL_LINUX
#error "This module is for Linux only."
#endif

static const char *config_keys[] = {"Device", "IgnoreSelected",
                                    "ForceUseProcfs"};

static const char *const dirname_sysfs = "/sys/class/thermal";
static const char *const dirname_procfs = "/proc/acpi/thermal_zone";

static bool force_procfs;
static ignorelist_t *device_list;

enum dev_type { TEMP = 0, COOLING_DEV };

static void thermal_submit(const char *plugin_instance, enum dev_type dt,
                           value_t value) {
  value_list_t vl = VALUE_LIST_INIT;

  vl.values = &value;
  vl.values_len = 1;

  sstrncpy(vl.plugin, "thermal", sizeof(vl.plugin));
  if (plugin_instance != NULL)
    sstrncpy(vl.plugin_instance, plugin_instance, sizeof(vl.plugin_instance));
  sstrncpy(vl.type, (dt == TEMP) ? "temperature" : "gauge", sizeof(vl.type));

  plugin_dispatch_values(&vl);
}

static int thermal_sysfs_device_read(const char __attribute__((unused)) * dir,
                                     const char *name,
                                     void __attribute__((unused)) * user_data) {
  char filename[PATH_MAX];
  bool success = false;
  value_t value;

  if (device_list && ignorelist_match(device_list, name))
    return -1;

  snprintf(filename, sizeof(filename), "%s/%s/temp", dirname_sysfs, name);
  if (parse_value_file(filename, &value, DS_TYPE_GAUGE) == 0) {
    value.gauge /= 1000.0;
    thermal_submit(name, TEMP, value);
    success = true;
  }

  snprintf(filename, sizeof(filename), "%s/%s/cur_state", dirname_sysfs, name);
  if (parse_value_file(filename, &value, DS_TYPE_GAUGE) == 0) {
    thermal_submit(name, COOLING_DEV, value);
    success = true;
  }

  return success ? 0 : -1;
}

static int thermal_procfs_device_read(const char __attribute__((unused)) * dir,
                                      const char *name,
                                      void __attribute__((unused)) *
                                          user_data) {
  const char str_temp[] = "temperature:";
  char filename[256];
  char data[1024];
  int len;

  if (device_list && ignorelist_match(device_list, name))
    return -1;

  /**
   * rechot ~ # cat /proc/acpi/thermal_zone/THRM/temperature
   * temperature:             55 C
   */

  len = snprintf(filename, sizeof(filename), "%s/%s/temperature",
                 dirname_procfs, name);
  if ((len < 0) || ((size_t)len >= sizeof(filename)))
    return -1;

  len = (ssize_t)read_text_file_contents(filename, data, sizeof(data));
  if ((len > 0) && ((size_t)len > sizeof(str_temp)) && (data[--len] == '\n') &&
      (!strncmp(data, str_temp, sizeof(str_temp) - 1))) {
    char *endptr = NULL;
    double temp;
    double factor, add;

    if (data[--len] == 'C') {
      add = 0;
      factor = 1.0;
    } else if (data[len] == 'F') {
      add = -32;
      factor = 5.0 / 9.0;
    } else if (data[len] == 'K') {
      add = -273.15;
      factor = 1.0;
    } else
      return -1;

    while (len > 0 && data[--len] == ' ')
      ;
    data[len + 1] = 0;

    while (len > 0 && data[--len] != ' ')
      ;
    ++len;

    errno = 0;
    temp = (strtod(data + len, &endptr) + add) * factor;

    if (endptr != data + len && errno == 0) {
      thermal_submit(name, TEMP, (value_t){.gauge = temp});
      return 0;
    }
  }

  return -1;
}

static int thermal_config(const char *key, const char *value) {
  if (device_list == NULL)
    device_list = ignorelist_create(1);

  if (strcasecmp(key, "Device") == 0) {
    if (ignorelist_add(device_list, value)) {
      ERROR("thermal plugin: "
            "Cannot add value to ignorelist.");
      return 1;
    }
  } else if (strcasecmp(key, "IgnoreSelected") == 0) {
    ignorelist_set_invert(device_list, 1);
    if (IS_TRUE(value))
      ignorelist_set_invert(device_list, 0);
  } else if (strcasecmp(key, "ForceUseProcfs") == 0) {
    force_procfs = false;
    if (IS_TRUE(value))
      force_procfs = true;
  } else {
    return -1;
  }

  return 0;
}

static int thermal_sysfs_read(void) {
  return walk_directory(dirname_sysfs, thermal_sysfs_device_read, NULL, 0);
}

static int thermal_procfs_read(void) {
  return walk_directory(dirname_procfs, thermal_procfs_device_read, NULL, 0);
}

static int thermal_init(void) {
  int ret = -1;

  if (!force_procfs && access(dirname_sysfs, R_OK | X_OK) == 0) {
    ret = plugin_register_read("thermal", thermal_sysfs_read);
  } else if (access(dirname_procfs, R_OK | X_OK) == 0) {
    ret = plugin_register_read("thermal", thermal_procfs_read);
  }

  return ret;
}

static int thermal_shutdown(void) {
  ignorelist_free(device_list);

  return 0;
}

void module_register(void) {
  plugin_register_config("thermal", thermal_config, config_keys,
                         STATIC_ARRAY_SIZE(config_keys));
  plugin_register_init("thermal", thermal_init);
  plugin_register_shutdown("thermal", thermal_shutdown);
}