/*
 * Copyright (C) 2014 Michal Ratajsky <michal.ratajsky@gmail.com>
 *
 * This library 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 of the licence, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

#include <glib.h>
#include <glib-object.h>
#include <sys/types.h>
#include <unistd.h>

#include <libmatemixer/matemixer-backend.h>
#include <libmatemixer/matemixer-backend-module.h>

#include <pulse/pulseaudio.h>
#include <pulse/thread-mainloop.h>

#include "pulse.h"
#include "pulse-device.h"

#define BACKEND_NAME      "PulseAudio"
#define BACKEND_PRIORITY   0

struct _MateMixerPulsePrivate
{
    pa_threaded_mainloop  *mainloop;
    pa_context            *context;
    GHashTable            *devices;
};

/* Support function for dynamic loading of the backend module */
void  backend_module_init (GTypeModule *module);

const MateMixerBackendModuleInfo *backend_module_get_info (void);

static void    mate_mixer_backend_interface_init (MateMixerBackendInterface *iface);

static void    pulse_card_info_cb (pa_context *c,
                                   const pa_card_info *info,
                                   int eol,
                                   void *userdata);

static void    pulse_card_update  (MateMixerPulse *pulse, const pa_card_info *i);

static void    pulse_state_cb     (pa_context *c, void *userdata);

static void    pulse_subscribe_cb (pa_context *c,
                                   pa_subscription_event_type_t t,
                                   uint32_t idx,
                                   void *userdata);

static gchar  *pulse_get_app_name (void);

G_DEFINE_DYNAMIC_TYPE_EXTENDED (MateMixerPulse, mate_mixer_pulse,
                                G_TYPE_OBJECT, 0,
                                G_IMPLEMENT_INTERFACE_DYNAMIC (MATE_MIXER_TYPE_BACKEND,
                                                               mate_mixer_backend_interface_init))

static MateMixerBackendModuleInfo info;

void
backend_module_init (GTypeModule *module)
{
    mate_mixer_pulse_register_type (module);

    info.name         = BACKEND_NAME;
    info.priority     = BACKEND_PRIORITY;
    info.g_type       = MATE_MIXER_TYPE_PULSE;
    info.backend_type = MATE_MIXER_BACKEND_TYPE_PULSE;
}

const MateMixerBackendModuleInfo *
backend_module_get_info (void)
{
    return &info;
}

static void
mate_mixer_backend_interface_init (MateMixerBackendInterface *iface)
{
    iface->open = mate_mixer_pulse_open;
    iface->close = mate_mixer_pulse_close;
    iface->list_devices = mate_mixer_pulse_list_devices;
}

static void
mate_mixer_pulse_init (MateMixerPulse *pulse)
{
    pulse->priv = G_TYPE_INSTANCE_GET_PRIVATE (
        pulse,
        MATE_MIXER_TYPE_PULSE,
        MateMixerPulsePrivate);

    pulse->priv->devices = g_hash_table_new_full (
        g_direct_hash,
        g_direct_equal,
        NULL,
        g_object_unref);
}

static void
mate_mixer_pulse_finalize (GObject *object)
{
    MateMixerPulse *pulse;

    pulse = MATE_MIXER_PULSE (object);

    g_hash_table_destroy (pulse->priv->devices);

    G_OBJECT_CLASS (mate_mixer_pulse_parent_class)->finalize (object);
}

static void
mate_mixer_pulse_class_init (MateMixerPulseClass *klass)
{
    GObjectClass *object_class;

    object_class = G_OBJECT_CLASS (klass);
    object_class->finalize = mate_mixer_pulse_finalize;

    g_type_class_add_private (object_class, sizeof (MateMixerPulsePrivate));
}

/* Called in the code generated by G_DEFINE_DYNAMIC_TYPE_EXTENDED() */
static void
mate_mixer_pulse_class_finalize (MateMixerPulseClass *klass)
{
}

gboolean
mate_mixer_pulse_open (MateMixerBackend *backend)
{
    int              ret;
    gchar           *app_name;
    MateMixerPulse  *pulse;

    g_return_val_if_fail (MATE_MIXER_IS_BACKEND (backend), FALSE);

    pulse = MATE_MIXER_PULSE (backend);

    g_return_val_if_fail (pulse->priv->mainloop == NULL, FALSE);

    pulse->priv->mainloop = pa_threaded_mainloop_new ();
    if (G_UNLIKELY (pulse->priv->mainloop == NULL)) {
        g_warning ("Failed to created PulseAudio main loop");
        return FALSE;
    }

    app_name = pulse_get_app_name ();

    pulse->priv->context = pa_context_new (
        pa_threaded_mainloop_get_api (pulse->priv->mainloop),
        app_name);

    g_free (app_name);

    if (G_UNLIKELY (pulse->priv->context == NULL)) {
        g_warning ("Failed to created PulseAudio context");

        pa_threaded_mainloop_free (pulse->priv->mainloop);
        pulse->priv->mainloop = NULL;
        return FALSE;
    }

    // XXX: investigate PA_CONTEXT_NOFAIL
    ret = pa_context_connect (pulse->priv->context, NULL, PA_CONTEXT_NOFLAGS, NULL);
    if (ret < 0) {
        g_warning ("Failed to connect to PulseAudio server: %s", pa_strerror (ret));

        pa_context_unref (pulse->priv->context);
        pa_threaded_mainloop_free (pulse->priv->mainloop);

        pulse->priv->context = NULL;
        pulse->priv->mainloop = NULL;
        return FALSE;
    }

    g_debug ("Connected to PulseAudio server");

    pa_threaded_mainloop_lock (pulse->priv->mainloop);

    pa_context_set_state_callback (pulse->priv->context,
        pulse_state_cb,
        backend);
    pa_context_set_subscribe_callback (pulse->priv->context,
        pulse_subscribe_cb,
        backend);

    ret = pa_threaded_mainloop_start (pulse->priv->mainloop);
    if (ret < 0) {
        g_warning ("Failed to start PulseAudio main loop: %s", pa_strerror (ret));

        pa_threaded_mainloop_unlock (pulse->priv->mainloop);

        pa_context_unref (pulse->priv->context);
        pa_threaded_mainloop_free (pulse->priv->mainloop);

        pulse->priv->context = NULL;
        pulse->priv->mainloop = NULL;
        return FALSE;
    }

    while (pa_context_get_state (pulse->priv->context) != PA_CONTEXT_READY) {
        // XXX this will get stuck if connection fails
        pa_threaded_mainloop_wait (pulse->priv->mainloop);
    }

    pa_threaded_mainloop_unlock (pulse->priv->mainloop);

    return TRUE;
}

void
mate_mixer_pulse_close (MateMixerBackend *backend)
{
    MateMixerPulse *pulse;

    g_return_if_fail (MATE_MIXER_IS_BACKEND (backend));

    pulse = MATE_MIXER_PULSE (backend);

    g_return_if_fail (pulse->priv->mainloop != NULL);

    pa_threaded_mainloop_stop (pulse->priv->mainloop);

    pa_context_unref (pulse->priv->context);
    pa_threaded_mainloop_free (pulse->priv->mainloop);

    pulse->priv->context = NULL;
    pulse->priv->mainloop = NULL;
}

GList *
mate_mixer_pulse_list_devices (MateMixerBackend *backend)
{
    MateMixerPulse  *pulse;
    pa_operation    *o;

    g_return_val_if_fail (MATE_MIXER_IS_BACKEND (backend), NULL);

    pulse = MATE_MIXER_PULSE (backend);

    pa_threaded_mainloop_lock (pulse->priv->mainloop);

    o = pa_context_get_card_info_list (pulse->priv->context, pulse_card_info_cb, pulse);
    if (o == NULL) {
        g_warning ("Failed to read card list: %s",
            pa_strerror (pa_context_errno (pulse->priv->context)));

        pa_threaded_mainloop_unlock (pulse->priv->mainloop);
        return NULL;
    }

    while (pa_operation_get_state (o) == PA_OPERATION_RUNNING)
        pa_threaded_mainloop_wait (pulse->priv->mainloop);

    pa_operation_unref (o);
    pa_threaded_mainloop_unlock (pulse->priv->mainloop);

    return g_hash_table_get_values (pulse->priv->devices);
}

static void
pulse_card_info_cb (pa_context *c, const pa_card_info *info, int eol, void *userdata)
{
    MateMixerPulse *pulse;

    pulse = MATE_MIXER_PULSE (userdata);

    if (!eol)
        pulse_card_update (pulse, info);

    pa_threaded_mainloop_signal (pulse->priv->mainloop, 0);
}

static void
pulse_card_update (MateMixerPulse *pulse, const pa_card_info *info)
{
    gpointer item;

    item = g_hash_table_lookup (pulse->priv->devices, GINT_TO_POINTER (info->index));
    if (item) {
        /* The card is already known, just update the fields that may
         * have changed */
        mate_mixer_pulse_device_update (MATE_MIXER_PULSE_DEVICE (item), info);
    } else {
        MateMixerPulseDevice *device = mate_mixer_pulse_device_new (info);

        if (G_UNLIKELY (device == NULL))
            g_warning ("Failed to process PulseAudio sound device");
        else
            g_hash_table_insert (
                pulse->priv->devices,
                GINT_TO_POINTER (info->index),
                device);
    }
}

static void
pulse_state_cb (pa_context *c, void *userdata)
{
    MateMixerPulse *pulse;

    pulse = MATE_MIXER_PULSE (userdata);

    // TODO: handle errors

    switch (pa_context_get_state (c)) {
    case PA_CONTEXT_UNCONNECTED:
        break;
    case PA_CONTEXT_CONNECTING:
        break;
    case PA_CONTEXT_AUTHORIZING:
        break;
    case PA_CONTEXT_SETTING_NAME:
        break;
    case PA_CONTEXT_READY:
        break;
    case PA_CONTEXT_FAILED:
        break;
    case PA_CONTEXT_TERMINATED:
        break;
    default:
        break;
    }

    pa_threaded_mainloop_signal (pulse->priv->mainloop, FALSE);
}

static void
pulse_subscribe_cb (pa_context *c,
                    pa_subscription_event_type_t t,
                    uint32_t idx,
                    void *userdata)
{
    // TODO
}

static gchar *
pulse_get_app_name (void)
{
    const char *name_app;
    char        name_buf[256];

    /* Inspired by GStreamer's pulse plugin */
    name_app = g_get_application_name ();
    if (name_app != NULL)
        return g_strdup (name_app);

    if (pa_get_binary_name (name_buf, sizeof (name_buf)) != NULL)
        return g_strdup (name_buf);

    return g_strdup_printf ("libmatemixer-%lu", (gulong) getpid ());
}