/**
 * collectd - src/battery.c
 * Copyright (C) 2006-2014  Florian octo Forster
 * Copyright (C) 2008       Michał Mirosław
 * Copyright (C) 2014       Andy Parkins
 *
 * 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:
 *   Florian octo Forster <octo at collectd.org>
 *   Michał Mirosław <mirq-linux at rere.qmqm.pl>
 *   Andy Parkins <andyp at fussylogic.co.uk>
 **/

#include "collectd.h"

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

#if HAVE_MACH_MACH_TYPES_H
#include <mach/mach_types.h>
#endif
#if HAVE_MACH_MACH_INIT_H
#include <mach/mach_init.h>
#endif
#if HAVE_MACH_MACH_ERROR_H
#include <mach/mach_error.h>
#endif
#if HAVE_COREFOUNDATION_COREFOUNDATION_H
#include <CoreFoundation/CoreFoundation.h>
#endif
#if HAVE_IOKIT_IOKITLIB_H
#include <IOKit/IOKitLib.h>
#endif
#if HAVE_IOKIT_IOTYPES_H
#include <IOKit/IOTypes.h>
#endif
#if HAVE_IOKIT_PS_IOPOWERSOURCES_H
#include <IOKit/ps/IOPowerSources.h>
#endif
#if HAVE_IOKIT_PS_IOPSKEYS_H
#include <IOKit/ps/IOPSKeys.h>
#endif

#if !HAVE_IOKIT_IOKITLIB_H && !HAVE_IOKIT_PS_IOPOWERSOURCES_H && !KERNEL_LINUX
#error "No applicable input method."
#endif

#if HAVE_IOKIT_IOKITLIB_H || HAVE_IOKIT_PS_IOPOWERSOURCES_H
/* No global variables */
/* #endif HAVE_IOKIT_IOKITLIB_H || HAVE_IOKIT_PS_IOPOWERSOURCES_H */

#elif KERNEL_LINUX
#define PROC_PMU_PATH_FORMAT "/proc/pmu/battery_%i"
#define PROC_ACPI_PATH "/proc/acpi/battery"
#define PROC_ACPI_FACTOR 0.001
#define SYSFS_PATH "/sys/class/power_supply"
#define SYSFS_FACTOR 0.000001
#endif /* KERNEL_LINUX */

int battery_read_statefs(
    void); /* defined in battery_statefs; used by StateFS backend */

static bool report_percent;
static bool report_degraded;
static bool query_statefs;

static void battery_submit2(char const *plugin_instance, /* {{{ */
                            char const *type, char const *type_instance,
                            gauge_t value) {
  value_list_t vl = VALUE_LIST_INIT;

  vl.values = &(value_t){.gauge = value};
  vl.values_len = 1;
  sstrncpy(vl.plugin, "battery", sizeof(vl.plugin));
  sstrncpy(vl.plugin_instance, plugin_instance, sizeof(vl.plugin_instance));
  sstrncpy(vl.type, type, sizeof(vl.type));
  if (type_instance != NULL)
    sstrncpy(vl.type_instance, type_instance, sizeof(vl.type_instance));

  plugin_dispatch_values(&vl);
} /* }}} void battery_submit2 */

static void battery_submit(char const *plugin_instance, /* {{{ */
                           char const *type, gauge_t value) {
  battery_submit2(plugin_instance, type, NULL, value);
} /* }}} void battery_submit */

static void submit_capacity(char const *plugin_instance, /* {{{ */
                            gauge_t capacity_charged, gauge_t capacity_full,
                            gauge_t capacity_design) {
  if (report_percent && (capacity_charged > capacity_full))
    return;
  if (report_degraded && (capacity_full > capacity_design))
    return;

  if (report_percent) {
    gauge_t capacity_max;

    if (report_degraded)
      capacity_max = capacity_design;
    else
      capacity_max = capacity_full;

    battery_submit2(plugin_instance, "percent", "charged",
                    100.0 * capacity_charged / capacity_max);
    battery_submit2(plugin_instance, "percent", "discharged",
                    100.0 * (capacity_full - capacity_charged) / capacity_max);

    if (report_degraded)
      battery_submit2(plugin_instance, "percent", "degraded",
                      100.0 * (capacity_design - capacity_full) / capacity_max);
  } else if (report_degraded) /* && !report_percent */
  {
    battery_submit2(plugin_instance, "capacity", "charged", capacity_charged);
    battery_submit2(plugin_instance, "capacity", "discharged",
                    (capacity_full - capacity_charged));
    battery_submit2(plugin_instance, "capacity", "degraded",
                    (capacity_design - capacity_full));
  } else /* !report_percent && !report_degraded */
  {
    battery_submit(plugin_instance, "capacity", capacity_charged);
  }
} /* }}} void submit_capacity */

#if HAVE_IOKIT_PS_IOPOWERSOURCES_H || HAVE_IOKIT_IOKITLIB_H
static double dict_get_double(CFDictionaryRef dict,
                              const char *key_string) /* {{{ */
{
  double val_double;
  long long val_int;
  CFNumberRef val_obj;
  CFStringRef key_obj;

  key_obj = CFStringCreateWithCString(kCFAllocatorDefault, key_string,
                                      kCFStringEncodingASCII);
  if (key_obj == NULL) {
    DEBUG("CFStringCreateWithCString (%s) failed.\n", key_string);
    return NAN;
  }

  if ((val_obj = CFDictionaryGetValue(dict, key_obj)) == NULL) {
    DEBUG("CFDictionaryGetValue (%s) failed.", key_string);
    CFRelease(key_obj);
    return NAN;
  }
  CFRelease(key_obj);

  if (CFGetTypeID(val_obj) == CFNumberGetTypeID()) {
    if (CFNumberIsFloatType(val_obj)) {
      CFNumberGetValue(val_obj, kCFNumberDoubleType, &val_double);
    } else {
      CFNumberGetValue(val_obj, kCFNumberLongLongType, &val_int);
      val_double = val_int;
    }
  } else {
    DEBUG("CFGetTypeID (val_obj) = %i", (int)CFGetTypeID(val_obj));
    return NAN;
  }

  return val_double;
} /* }}} double dict_get_double */

#if HAVE_IOKIT_PS_IOPOWERSOURCES_H
static void get_via_io_power_sources(double *ret_charge, /* {{{ */
                                     double *ret_current, double *ret_voltage) {
  CFTypeRef ps_raw;
  CFArrayRef ps_array;
  int ps_array_len;
  CFDictionaryRef ps_dict;
  CFTypeRef ps_obj;

  double temp_double;

  ps_raw = IOPSCopyPowerSourcesInfo();
  ps_array = IOPSCopyPowerSourcesList(ps_raw);
  ps_array_len = CFArrayGetCount(ps_array);

  DEBUG("ps_array_len == %i", ps_array_len);

  for (int i = 0; i < ps_array_len; i++) {
    ps_obj = CFArrayGetValueAtIndex(ps_array, i);
    ps_dict = IOPSGetPowerSourceDescription(ps_raw, ps_obj);

    if (ps_dict == NULL) {
      DEBUG("IOPSGetPowerSourceDescription failed.");
      continue;
    }

    if (CFGetTypeID(ps_dict) != CFDictionaryGetTypeID()) {
      DEBUG("IOPSGetPowerSourceDescription did not return a CFDictionaryRef");
      continue;
    }

    /* FIXME: Check if this is really an internal battery */

    if (isnan(*ret_charge)) {
      /* This is the charge in percent. */
      temp_double = dict_get_double(ps_dict, kIOPSCurrentCapacityKey);
      if (!isnan((temp_double)) && (temp_double >= 0.0) &&
          (temp_double <= 100.0))
        *ret_charge = temp_double;
    }

    if (isnan(*ret_current)) {
      temp_double = dict_get_double(ps_dict, kIOPSCurrentKey);
      if (!isnan(temp_double))
        *ret_current = temp_double / 1000.0;
    }

    if (isnan(*ret_voltage)) {
      temp_double = dict_get_double(ps_dict, kIOPSVoltageKey);
      if (!isnan(temp_double))
        *ret_voltage = temp_double / 1000.0;
    }
  }

  CFRelease(ps_array);
  CFRelease(ps_raw);
} /* }}} void get_via_io_power_sources */
#endif /* HAVE_IOKIT_PS_IOPOWERSOURCES_H */

#if HAVE_IOKIT_IOKITLIB_H
static void get_via_generic_iokit(double *ret_capacity_full, /* {{{ */
                                  double *ret_capacity_design,
                                  double *ret_current, double *ret_voltage) {
  kern_return_t status;
  io_iterator_t iterator;
  io_object_t io_obj;

  CFDictionaryRef bat_root_dict;
  CFArrayRef bat_info_arry;
  CFIndex bat_info_arry_len;
  CFDictionaryRef bat_info_dict;

  double temp_double;

  status = IOServiceGetMatchingServices(
      kIOMasterPortDefault, IOServiceNameMatching("battery"), &iterator);
  if (status != kIOReturnSuccess) {
    DEBUG("IOServiceGetMatchingServices failed.");
    return;
  }

  while ((io_obj = IOIteratorNext(iterator))) {
    status = IORegistryEntryCreateCFProperties(
        io_obj, (CFMutableDictionaryRef *)&bat_root_dict, kCFAllocatorDefault,
        kNilOptions);
    if (status != kIOReturnSuccess) {
      DEBUG("IORegistryEntryCreateCFProperties failed.");
      continue;
    }

    bat_info_arry =
        (CFArrayRef)CFDictionaryGetValue(bat_root_dict, CFSTR("IOBatteryInfo"));
    if (bat_info_arry == NULL) {
      CFRelease(bat_root_dict);
      continue;
    }
    bat_info_arry_len = CFArrayGetCount(bat_info_arry);

    for (CFIndex bat_info_arry_pos = 0; bat_info_arry_pos < bat_info_arry_len;
         bat_info_arry_pos++) {
      bat_info_dict = (CFDictionaryRef)CFArrayGetValueAtIndex(
          bat_info_arry, bat_info_arry_pos);

      if (isnan(*ret_capacity_full)) {
        temp_double = dict_get_double(bat_info_dict, "Capacity");
        *ret_capacity_full = temp_double / 1000.0;
      }

      if (isnan(*ret_capacity_design)) {
        temp_double = dict_get_double(bat_info_dict, "AbsoluteMaxCapacity");
        *ret_capacity_design = temp_double / 1000.0;
      }

      if (isnan(*ret_current)) {
        temp_double = dict_get_double(bat_info_dict, "Current");
        *ret_current = temp_double / 1000.0;
      }

      if (isnan(*ret_voltage)) {
        temp_double = dict_get_double(bat_info_dict, "Voltage");
        *ret_voltage = temp_double / 1000.0;
      }
    }

    CFRelease(bat_root_dict);
  }

  IOObjectRelease(iterator);
} /* }}} void get_via_generic_iokit */
#endif /* HAVE_IOKIT_IOKITLIB_H */

static int battery_read(void) /* {{{ */
{
  gauge_t current = NAN; /* Current in A */
  gauge_t voltage = NAN; /* Voltage in V */

  /* We only get the charged capacity as a percentage from
   * IOPowerSources. IOKit, on the other hand, only reports the full
   * capacity. We use the two to calculate the current charged capacity. */
  gauge_t charge_rel = NAN;      /* Current charge in percent */
  gauge_t capacity_charged;      /* Charged capacity */
  gauge_t capacity_full = NAN;   /* Total capacity */
  gauge_t capacity_design = NAN; /* Full design capacity */

  if (query_statefs)
    return battery_read_statefs();

#if HAVE_IOKIT_PS_IOPOWERSOURCES_H
  get_via_io_power_sources(&charge_rel, &current, &voltage);
#endif
#if HAVE_IOKIT_IOKITLIB_H
  get_via_generic_iokit(&capacity_full, &capacity_design, &current, &voltage);
#endif

  capacity_charged = charge_rel * capacity_full / 100.0;
  submit_capacity("0", capacity_charged, capacity_full, capacity_design);

  if (!isnan(current))
    battery_submit("0", "current", current);
  if (!isnan(voltage))
    battery_submit("0", "voltage", voltage);

  return 0;
} /* }}} int battery_read */
  /* #endif HAVE_IOKIT_IOKITLIB_H || HAVE_IOKIT_PS_IOPOWERSOURCES_H */

#elif KERNEL_LINUX
/* Reads a file which contains only a number (and optionally a trailing
 * newline) and parses that number. */
static int sysfs_file_to_buffer(char const *dir, /* {{{ */
                                char const *power_supply, char const *basename,
                                char *buffer, size_t buffer_size) {
  char filename[PATH_MAX];
  int status;

  snprintf(filename, sizeof(filename), "%s/%s/%s", dir, power_supply, basename);

  status = (int)read_text_file_contents(filename, buffer, buffer_size);
  if (status < 0)
    return status;

  strstripnewline(buffer);
  return 0;
} /* }}} int sysfs_file_to_buffer */

/* Reads a file which contains only a number (and optionally a trailing
 * newline) and parses that number. */
static int sysfs_file_to_gauge(char const *dir, /* {{{ */
                               char const *power_supply, char const *basename,
                               gauge_t *ret_value) {
  int status;
  char buffer[32];

  status =
      sysfs_file_to_buffer(dir, power_supply, basename, buffer, sizeof(buffer));
  if (status != 0)
    return status;

  return strtogauge(buffer, ret_value);
} /* }}} sysfs_file_to_gauge */

static int read_sysfs_capacity(char const *dir, /* {{{ */
                               char const *power_supply,
                               char const *plugin_instance) {
  gauge_t capacity_charged = NAN;
  gauge_t capacity_full = NAN;
  gauge_t capacity_design = NAN;
  int status;

  status =
      sysfs_file_to_gauge(dir, power_supply, "energy_now", &capacity_charged);
  if (status != 0)
    return status;

  status =
      sysfs_file_to_gauge(dir, power_supply, "energy_full", &capacity_full);
  if (status != 0)
    return status;

  status = sysfs_file_to_gauge(dir, power_supply, "energy_full_design",
                               &capacity_design);
  if (status != 0)
    return status;

  submit_capacity(plugin_instance, capacity_charged * SYSFS_FACTOR,
                  capacity_full * SYSFS_FACTOR, capacity_design * SYSFS_FACTOR);
  return 0;
} /* }}} int read_sysfs_capacity */

static int read_sysfs_capacity_from_charge(char const *dir, /* {{{ */
                                           char const *power_supply,
                                           char const *plugin_instance) {
  gauge_t capacity_charged = NAN;
  gauge_t capacity_full = NAN;
  gauge_t capacity_design = NAN;
  gauge_t voltage_min_design = NAN;
  int status;

  status = sysfs_file_to_gauge(dir, power_supply, "voltage_min_design",
                               &voltage_min_design);
  if (status != 0)
    return status;
  voltage_min_design *= SYSFS_FACTOR;

  status =
      sysfs_file_to_gauge(dir, power_supply, "charge_now", &capacity_charged);
  if (status != 0)
    return status;
  capacity_charged *= voltage_min_design;

  status =
      sysfs_file_to_gauge(dir, power_supply, "charge_full", &capacity_full);
  if (status != 0)
    return status;
  capacity_full *= voltage_min_design;

  status = sysfs_file_to_gauge(dir, power_supply, "charge_full_design",
                               &capacity_design);
  if (status != 0)
    return status;
  capacity_design *= voltage_min_design;

  submit_capacity(plugin_instance, capacity_charged * SYSFS_FACTOR,
                  capacity_full * SYSFS_FACTOR, capacity_design * SYSFS_FACTOR);
  return 0;
} /* }}} int read_sysfs_capacity_from_charge */

static int read_sysfs_callback(char const *dir, /* {{{ */
                               char const *power_supply, void *user_data) {
  int *battery_index = user_data;

  char const *plugin_instance;
  char buffer[32];
  gauge_t v = NAN;
  bool discharging = false;
  int status;

  /* Ignore non-battery directories, such as AC power. */
  status =
      sysfs_file_to_buffer(dir, power_supply, "type", buffer, sizeof(buffer));
  if (status != 0)
    return 0;
  if (strcasecmp("Battery", buffer) != 0)
    return 0;

  (void)sysfs_file_to_buffer(dir, power_supply, "status", buffer,
                             sizeof(buffer));
  if (strcasecmp("Discharging", buffer) == 0)
    discharging = true;

  /* FIXME: This is a dirty hack for backwards compatibility: The battery
   * plugin, for a very long time, has had the plugin_instance
   * hard-coded to "0". So, to keep backwards compatibility, we'll use
   * "0" for the first battery we find and the power_supply name for all
   * following. This should be reverted in a future major version. */
  plugin_instance = (*battery_index == 0) ? "0" : power_supply;
  (*battery_index)++;

  if (sysfs_file_to_gauge(dir, power_supply, "energy_now", &v) == 0)
    read_sysfs_capacity(dir, power_supply, plugin_instance);
  else
    read_sysfs_capacity_from_charge(dir, power_supply, plugin_instance);

  if (sysfs_file_to_gauge(dir, power_supply, "power_now", &v) == 0) {
    if (discharging)
      v *= -1.0;
    battery_submit(plugin_instance, "power", v * SYSFS_FACTOR);
  }
  if (sysfs_file_to_gauge(dir, power_supply, "current_now", &v) == 0) {
    if (discharging)
      v *= -1.0;
    battery_submit(plugin_instance, "current", v * SYSFS_FACTOR);
  }

  if (sysfs_file_to_gauge(dir, power_supply, "voltage_now", &v) == 0)
    battery_submit(plugin_instance, "voltage", v * SYSFS_FACTOR);

  return 0;
} /* }}} int read_sysfs_callback */

static int read_sysfs(void) /* {{{ */
{
  int status;
  int battery_counter = 0;

  if (access(SYSFS_PATH, R_OK) != 0)
    return ENOENT;

  status = walk_directory(SYSFS_PATH, read_sysfs_callback,
                          /* user_data = */ &battery_counter,
                          /* include hidden */ 0);
  return status;
} /* }}} int read_sysfs */

static int read_acpi_full_capacity(char const *dir, /* {{{ */
                                   char const *power_supply,
                                   gauge_t *ret_capacity_full,
                                   gauge_t *ret_capacity_design)

{
  char filename[PATH_MAX];
  char buffer[1024];

  FILE *fh;

  snprintf(filename, sizeof(filename), "%s/%s/info", dir, power_supply);
  fh = fopen(filename, "r");
  if (fh == NULL)
    return errno;

  /* last full capacity:      40090 mWh */
  while (fgets(buffer, sizeof(buffer), fh) != NULL) {
    gauge_t *value_ptr;
    int fields_num;
    char *fields[8];
    int index;

    if (strncmp("last full capacity:", buffer, strlen("last full capacity:")) ==
        0) {
      value_ptr = ret_capacity_full;
      index = 3;
    } else if (strncmp("design capacity:", buffer,
                       strlen("design capacity:")) == 0) {
      value_ptr = ret_capacity_design;
      index = 2;
    } else {
      continue;
    }

    fields_num = strsplit(buffer, fields, STATIC_ARRAY_SIZE(fields));
    if (fields_num <= index)
      continue;

    strtogauge(fields[index], value_ptr);
  }

  fclose(fh);
  return 0;
} /* }}} int read_acpi_full_capacity */

static int read_acpi_callback(char const *dir, /* {{{ */
                              char const *power_supply, void *user_data) {
  int *battery_index = user_data;

  gauge_t power = NAN;
  gauge_t voltage = NAN;
  gauge_t capacity_charged = NAN;
  gauge_t capacity_full = NAN;
  gauge_t capacity_design = NAN;
  bool charging = false;
  bool is_current = false;

  char const *plugin_instance;
  char filename[PATH_MAX];
  char buffer[1024];

  FILE *fh;

  snprintf(filename, sizeof(filename), "%s/%s/state", dir, power_supply);
  fh = fopen(filename, "r");
  if (fh == NULL) {
    if ((errno == EAGAIN) || (errno == EINTR) || (errno == ENOENT))
      return 0;
    else
      return errno;
  }

  /*
   * [11:00] <@tokkee> $ cat /proc/acpi/battery/BAT1/state
   * [11:00] <@tokkee> present:                 yes
   * [11:00] <@tokkee> capacity state:          ok
   * [11:00] <@tokkee> charging state:          charging
   * [11:00] <@tokkee> present rate:            1724 mA
   * [11:00] <@tokkee> remaining capacity:      4136 mAh
   * [11:00] <@tokkee> present voltage:         12428 mV
   */
  while (fgets(buffer, sizeof(buffer), fh) != NULL) {
    char *fields[8];
    int numfields;

    numfields = strsplit(buffer, fields, STATIC_ARRAY_SIZE(fields));
    if (numfields < 3)
      continue;

    if ((strcmp(fields[0], "charging") == 0) &&
        (strcmp(fields[1], "state:") == 0)) {
      if (strcmp(fields[2], "charging") == 0)
        charging = true;
      else
        charging = false;
      continue;
    }

    /* The unit of "present rate" depends on the battery. Modern
     * batteries export power (watts), older batteries (used to)
     * export current (amperes). We check the fourth column and try
     * to find old batteries this way. */
    if ((strcmp(fields[0], "present") == 0) &&
        (strcmp(fields[1], "rate:") == 0)) {
      strtogauge(fields[2], &power);

      if ((numfields >= 4) && (strcmp("mA", fields[3]) == 0))
        is_current = true;
    } else if ((strcmp(fields[0], "remaining") == 0) &&
               (strcmp(fields[1], "capacity:") == 0))
      strtogauge(fields[2], &capacity_charged);
    else if ((strcmp(fields[0], "present") == 0) &&
             (strcmp(fields[1], "voltage:") == 0))
      strtogauge(fields[2], &voltage);
  } /* while (fgets (buffer, sizeof (buffer), fh) != NULL) */

  fclose(fh);

  if (!charging)
    power *= -1.0;

  /* FIXME: This is a dirty hack for backwards compatibility: The battery
   * plugin, for a very long time, has had the plugin_instance
   * hard-coded to "0". So, to keep backwards compatibility, we'll use
   * "0" for the first battery we find and the power_supply name for all
   * following. This should be reverted in a future major version. */
  plugin_instance = (*battery_index == 0) ? "0" : power_supply;
  (*battery_index)++;

  read_acpi_full_capacity(dir, power_supply, &capacity_full, &capacity_design);

  submit_capacity(plugin_instance, capacity_charged * PROC_ACPI_FACTOR,
                  capacity_full * PROC_ACPI_FACTOR,
                  capacity_design * PROC_ACPI_FACTOR);

  battery_submit(plugin_instance, is_current ? "current" : "power",
                 power * PROC_ACPI_FACTOR);
  battery_submit(plugin_instance, "voltage", voltage * PROC_ACPI_FACTOR);

  return 0;
} /* }}} int read_acpi_callback */

static int read_acpi(void) /* {{{ */
{
  int status;
  int battery_counter = 0;

  if (access(PROC_ACPI_PATH, R_OK) != 0)
    return ENOENT;

  status = walk_directory(PROC_ACPI_PATH, read_acpi_callback,
                          /* user_data = */ &battery_counter,
                          /* include hidden */ 0);
  return status;
} /* }}} int read_acpi */

static int read_pmu(void) /* {{{ */
{
  int i = 0;
  /* The upper limit here is just a safeguard. If there is a system with
   * more than 100 batteries, this can easily be increased. */
  for (; i < 100; i++) {
    FILE *fh;

    char buffer[1024];
    char filename[PATH_MAX];
    char plugin_instance[DATA_MAX_NAME_LEN];

    gauge_t current = NAN;
    gauge_t voltage = NAN;
    gauge_t charge = NAN;

    snprintf(filename, sizeof(filename), PROC_PMU_PATH_FORMAT, i);
    if (access(filename, R_OK) != 0)
      break;

    snprintf(plugin_instance, sizeof(plugin_instance), "%i", i);

    fh = fopen(filename, "r");
    if (fh == NULL) {
      if (errno == ENOENT)
        break;
      else if ((errno == EAGAIN) || (errno == EINTR))
        continue;
      else
        return errno;
    }

    while (fgets(buffer, sizeof(buffer), fh) != NULL) {
      char *fields[8];
      int numfields;

      numfields = strsplit(buffer, fields, STATIC_ARRAY_SIZE(fields));
      if (numfields < 3)
        continue;

      if (strcmp("current", fields[0]) == 0)
        strtogauge(fields[2], &current);
      else if (strcmp("voltage", fields[0]) == 0)
        strtogauge(fields[2], &voltage);
      else if (strcmp("charge", fields[0]) == 0)
        strtogauge(fields[2], &charge);
    }

    fclose(fh);
    fh = NULL;

    battery_submit(plugin_instance, "charge", charge / 1000.0);
    battery_submit(plugin_instance, "current", current / 1000.0);
    battery_submit(plugin_instance, "voltage", voltage / 1000.0);
  }

  if (i == 0)
    return ENOENT;
  return 0;
} /* }}} int read_pmu */

static int battery_read(void) /* {{{ */
{
  int status;

  if (query_statefs)
    return battery_read_statefs();

  DEBUG("battery plugin: Trying sysfs ...");
  status = read_sysfs();
  if (status == 0)
    return 0;

  DEBUG("battery plugin: Trying acpi ...");
  status = read_acpi();
  if (status == 0)
    return 0;

  DEBUG("battery plugin: Trying pmu ...");
  status = read_pmu();
  if (status == 0)
    return 0;

  ERROR("battery plugin: All available input methods failed.");
  return -1;
} /* }}} int battery_read */
#endif /* KERNEL_LINUX */

static int battery_config(oconfig_item_t *ci) {
  for (int i = 0; i < ci->children_num; i++) {
    oconfig_item_t *child = ci->children + i;

    if (strcasecmp("ValuesPercentage", child->key) == 0)
      cf_util_get_boolean(child, &report_percent);
    else if (strcasecmp("ReportDegraded", child->key) == 0)
      cf_util_get_boolean(child, &report_degraded);
    else if (strcasecmp("QueryStateFS", child->key) == 0)
      cf_util_get_boolean(child, &query_statefs);
    else
      WARNING("battery plugin: Ignoring unknown "
              "configuration option \"%s\".",
              child->key);
  }

  return 0;
} /* }}} int battery_config */

void module_register(void) {
  plugin_register_complex_config("battery", battery_config);
  plugin_register_read("battery", battery_read);
} /* void module_register */