/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <errno.h>
#include <getopt.h>
#include <sys/socket.h>
#include <unistd.h>

#include "battery-util.h"
#include "build.h"
#include "constants.h"
#include "errno-util.h"
#include "glyph-util.h"
#include "fd-util.h"
#include "io-util.h"
#include "log.h"
#include "main-func.h"
#include "parse-util.h"
#include "pretty-print.h"
#include "proc-cmdline.h"
#include "socket-util.h"
#include "terminal-util.h"
#include "time-util.h"

#define BATTERY_LOW_MESSAGE \
        "Battery level critically low. Please connect your charger or the system will power off in 10 seconds."
#define BATTERY_RESTORED_MESSAGE \
        "A.C. power restored, continuing."

static bool arg_doit = true;

static int help(void) {
        _cleanup_free_ char *link = NULL;
        int r;

        r = terminal_urlify_man("systemd-battery-check", "8", &link);
        if (r < 0)
                return log_oom();

        printf("%s\n\n"
               "%sCheck battery level to see whether there's enough charge.%s\n\n"
               "   -h --help            Show this help\n"
               "      --version         Show package version\n"
               "\nSee the %s for details.\n",
               program_invocation_short_name,
               ansi_highlight(),
               ansi_normal(),
               link);

        return 0;
}

static bool ERRNO_IS_NO_PLYMOUTH(int r) {
        return IN_SET(abs(r), EAGAIN, ENOENT) || ERRNO_IS_DISCONNECT(r);
}

static int plymouth_send_message(const char *mode, const char *message) {
        static const union sockaddr_union sa = PLYMOUTH_SOCKET;
        _cleanup_free_ char *plymouth_message = NULL;
        _cleanup_close_ int fd = -EBADF;
        int c, r;

        assert(mode);
        assert(message);

        c = asprintf(&plymouth_message,
                     "C\x02%c%s%c"
                     "M\x02%c%s%c",
                     (int) strlen(mode) + 1, mode, '\x00',
                     (int) strlen(message) + 1, message, '\x00');
        if (c < 0)
                return log_oom();

        /* We set SOCK_NONBLOCK here so that we rather drop the
         * message than wait for plymouth */
        fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
        if (fd < 0)
                return log_warning_errno(errno, "socket() failed: %m");

        if (connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un)) < 0)
                return log_full_errno(ERRNO_IS_NO_PLYMOUTH(errno) ? LOG_DEBUG : LOG_WARNING, errno,
                                      "Failed to connect to plymouth: %m");

        r = loop_write(fd, plymouth_message, c, /* do_poll = */ false);
        if (r < 0)
                return log_full_errno(ERRNO_IS_NO_PLYMOUTH(r) ? LOG_DEBUG : LOG_WARNING, r,
                                      "Failed to write to plymouth: %m");

        return 0;
}

static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
        int r;

        assert(key);

        if (streq(key, "systemd.battery-check")) {

                r = value ? parse_boolean(value) : 1;
                if (r < 0)
                        log_warning_errno(r, "Failed to parse %s switch, ignoring: %s", key, value);
                else
                        arg_doit = r;
        }

        return 0;
}

static int parse_argv(int argc, char * argv[]) {

        enum {
                ARG_VERSION = 0x100,
        };

        static const struct option options[] = {
                { "help",    no_argument, NULL, 'h'         },
                { "version", no_argument, NULL, ARG_VERSION },
                {}
        };

        int c;

        assert(argc >= 0);
        assert(argv);

        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)

                switch (c) {

                case 'h':
                        return help();

                case ARG_VERSION:
                        return version();

                case '?':
                        return -EINVAL;

                default:
                        assert_not_reached();
                }

        if (optind < argc)
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "%s takes no argument.",
                                       program_invocation_short_name);
        return 1;
}

static int run(int argc, char *argv[]) {
        _cleanup_free_ char *plymouth_message = NULL;
        _cleanup_close_ int fd = -EBADF;
        int r;

        log_setup();

        r = parse_argv(argc, argv);
        if (r <= 0)
                return r;

        r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_STRIP_RD_PREFIX);
        if (r < 0)
                log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");

        if (!arg_doit) {
                log_info("Checking battery status and AC power existence is disabled by the kernel command line, skipping execution.");
                return 0;
        }

        r = battery_is_discharging_and_low();
        if (r < 0) {
                log_warning_errno(r, "Failed to check battery status, ignoring: %m");
                return 0;
        }
        if (r == 0)
                return 0;

        log_emergency("%s " BATTERY_LOW_MESSAGE, special_glyph(SPECIAL_GLYPH_LOW_BATTERY));

        fd = open_terminal("/dev/console", O_WRONLY|O_NOCTTY|O_CLOEXEC);
        if (fd < 0)
                log_warning_errno(fd, "Failed to open console, ignoring: %m");
        else
                dprintf(fd, ANSI_HIGHLIGHT_RED "%s " BATTERY_LOW_MESSAGE ANSI_NORMAL "\n",
                        special_glyph_full(SPECIAL_GLYPH_LOW_BATTERY, /* force_utf = */ false));

        if (asprintf(&plymouth_message, "%s " BATTERY_LOW_MESSAGE,
                     special_glyph_full(SPECIAL_GLYPH_LOW_BATTERY, /* force_utf = */ true)) < 0)
                return log_oom();

        (void) plymouth_send_message("shutdown", plymouth_message);

        usleep_safe(10 * USEC_PER_SEC);

        r = battery_is_discharging_and_low();
        if (r < 0)
                return log_warning_errno(r, "Failed to check battery status, assuming not charged yet, powering off: %m");
        if (r > 0) {
                log_emergency("Battery level critically low, powering off.");
                return r;
        }

        log_info(BATTERY_RESTORED_MESSAGE);
        if (fd >= 0)
                dprintf(fd, BATTERY_RESTORED_MESSAGE "\n");
        (void) plymouth_send_message("boot-up", BATTERY_RESTORED_MESSAGE);

        return 0;
}

DEFINE_MAIN_FUNCTION_WITH_POSITIVE_FAILURE(run);
