/***
  This file is part of PulseAudio.

  Copyright 2005-2006 Lennart Poettering

  PulseAudio is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published
  by the Free Software Foundation; either version 2.1 of the License,
  or (at your option) any later version.

  PulseAudio 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 Lesser General Public License
  along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
***/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>

#include <linux/input.h>

#include <pulse/xmalloc.h>

#include <pulsecore/core-error.h>
#include <pulsecore/module.h>
#include <pulsecore/log.h>
#include <pulsecore/namereg.h>
#include <pulsecore/sink.h>
#include <pulsecore/modargs.h>
#include <pulsecore/core-util.h>

PA_MODULE_AUTHOR("Lennart Poettering");
PA_MODULE_DESCRIPTION("Multimedia keyboard support via Linux evdev");
PA_MODULE_VERSION(PACKAGE_VERSION);
PA_MODULE_LOAD_ONCE(false);
PA_MODULE_USAGE("device=<evdev device> sink=<sink name> volume_limit=<volume limit> volume_step=<volume change step>");

#define DEFAULT_DEVICE "/dev/input/event0"

static const char* const valid_modargs[] = {
    "device",
    "sink",
    "volume_limit",
    "volume_step",
    NULL,
};

struct userdata {
    int fd, fd_type;
    pa_io_event *io;
    char *sink_name;
    pa_module *module;
    pa_volume_t volume_limit;
    pa_volume_t volume_step;
};

static void io_callback(pa_mainloop_api *io, pa_io_event *e, int fd, pa_io_event_flags_t events, void*userdata) {
    struct userdata *u = userdata;

    pa_assert(io);
    pa_assert(u);

    if (events & (PA_IO_EVENT_HANGUP|PA_IO_EVENT_ERROR)) {
        pa_log("Lost connection to evdev device.");
        goto fail;
    }

    if (events & PA_IO_EVENT_INPUT) {
        struct input_event ev;

        if (pa_loop_read(u->fd, &ev, sizeof(ev), &u->fd_type) <= 0) {
            pa_log("Failed to read from event device: %s", pa_cstrerror(errno));
            goto fail;
        }

        if (ev.type == EV_KEY && (ev.value == 1 || ev.value == 2)) {
            enum {
                INVALID,
                UP,
                DOWN,
                MUTE_TOGGLE
            } volchange = INVALID;

            pa_log_debug("Key code=%u, value=%u", ev.code, ev.value);

            switch (ev.code) {
                case KEY_VOLUMEDOWN:
                    volchange = DOWN;
                    break;

                case KEY_VOLUMEUP:
                    volchange = UP;
                    break;

                case KEY_MUTE:
                    volchange = MUTE_TOGGLE;
                    break;
            }

            if (volchange != INVALID) {
                pa_sink *s;

                if (!(s = pa_namereg_get(u->module->core, u->sink_name, PA_NAMEREG_SINK)))
                    pa_log("Failed to get sink '%s'", u->sink_name);
                else {
                    pa_cvolume cv = *pa_sink_get_volume(s, false);

                    switch (volchange) {
                        case UP:
                            pa_cvolume_inc_clamp(&cv, u->volume_step, u->volume_limit);
                            pa_sink_set_volume(s, &cv, true, true);
                            break;

                        case DOWN:
                            pa_cvolume_dec(&cv, u->volume_step);
                            pa_sink_set_volume(s, &cv, true, true);
                            break;

                        case MUTE_TOGGLE:
                            pa_sink_set_mute(s, !pa_sink_get_mute(s, false), true);
                            break;

                        case INVALID:
                            pa_assert_not_reached();
                    }
                }
            }
        }
    }

    return;

fail:
    u->module->core->mainloop->io_free(u->io);
    u->io = NULL;

    pa_module_unload_request(u->module, true);
}

#define test_bit(bit, array) (array[bit/8] & (1<<(bit%8)))

int pa__init(pa_module*m) {

    pa_modargs *ma = NULL;
    struct userdata *u;
    int version;
    struct input_id input_id;
    char name[256];
    uint8_t evtype_bitmask[EV_MAX/8 + 1];
    pa_volume_t volume_limit = PA_VOLUME_NORM*3/2;
    pa_volume_t volume_step = PA_VOLUME_NORM/20;

    pa_assert(m);

    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
        pa_log("Failed to parse module arguments");
        goto fail;
    }

    if (pa_modargs_get_value_u32(ma, "volume_limit", &volume_limit) < 0) {
        pa_log("Failed to parse volume limit");
        goto fail;
    }

    if (pa_modargs_get_value_u32(ma, "volume_step", &volume_step) < 0) {
        pa_log("Failed to parse volume step");
        goto fail;
    }

    m->userdata = u = pa_xnew(struct userdata, 1);
    u->module = m;
    u->io = NULL;
    u->sink_name = pa_xstrdup(pa_modargs_get_value(ma, "sink", NULL));
    u->fd = -1;
    u->fd_type = 0;
    u->volume_limit = PA_CLAMP_VOLUME(volume_limit);
    u->volume_step = PA_CLAMP_VOLUME(volume_step);

    if ((u->fd = pa_open_cloexec(pa_modargs_get_value(ma, "device", DEFAULT_DEVICE), O_RDONLY, 0)) < 0) {
        pa_log("Failed to open evdev device: %s", pa_cstrerror(errno));
        goto fail;
    }

    if (ioctl(u->fd, EVIOCGVERSION, &version) < 0) {
        pa_log("EVIOCGVERSION failed: %s", pa_cstrerror(errno));
        goto fail;
    }

    pa_log_info("evdev driver version %i.%i.%i", version >> 16, (version >> 8) & 0xff, version & 0xff);

    if (ioctl(u->fd, EVIOCGID, &input_id)) {
        pa_log("EVIOCGID failed: %s", pa_cstrerror(errno));
        goto fail;
    }

    pa_log_info("evdev vendor 0x%04hx product 0x%04hx version 0x%04hx bustype %u",
                input_id.vendor, input_id.product, input_id.version, input_id.bustype);

    memset(name, 0, sizeof(name));
    if (ioctl(u->fd, EVIOCGNAME(sizeof(name)), name) < 0) {
        pa_log("EVIOCGNAME failed: %s", pa_cstrerror(errno));
        goto fail;
    }

    pa_log_info("evdev device name: %s", name);

    memset(evtype_bitmask, 0, sizeof(evtype_bitmask));
    if (ioctl(u->fd, EVIOCGBIT(0, EV_MAX), evtype_bitmask) < 0) {
        pa_log("EVIOCGBIT failed: %s", pa_cstrerror(errno));
        goto fail;
    }

    if (!test_bit(EV_KEY, evtype_bitmask)) {
        pa_log("Device has no keys.");
        goto fail;
    }

    u->io = m->core->mainloop->io_new(m->core->mainloop, u->fd, PA_IO_EVENT_INPUT|PA_IO_EVENT_HANGUP, io_callback, u);

    pa_modargs_free(ma);

    return 0;

fail:

    if (ma)
        pa_modargs_free(ma);

    pa__done(m);
    return -1;
}

void pa__done(pa_module*m) {
    struct userdata *u;

    pa_assert(m);

    if (!(u = m->userdata))
        return;

    if (u->io)
        m->core->mainloop->io_free(u->io);

    if (u->fd >= 0) {
        int r = pa_close(u->fd);
        if (r < 0) /* https://bugs.freedesktop.org/show_bug.cgi?id=80867 */
            pa_log("Closing fd failed: %s", pa_cstrerror(errno));
    }

    pa_xfree(u->sink_name);
    pa_xfree(u);
}