/* Called from main thread */
static void sink_input_moving_cb(pa_sink_input *i, pa_sink *dest) {
    struct userdata *u;
    pa_proplist *p;
    const char *n;

    if (!dest)
        return;

    pa_sink_input_assert_ref(i);
    pa_assert_ctl_context();
    pa_assert_se(u = i->userdata);

    p = pa_proplist_new();
    pa_proplist_setf(p, PA_PROP_MEDIA_NAME, "Loopback to %s", pa_strnull(pa_proplist_gets(dest->proplist, PA_PROP_DEVICE_DESCRIPTION)));

    if ((n = pa_proplist_gets(dest->proplist, PA_PROP_DEVICE_ICON_NAME)))
        pa_proplist_sets(p, PA_PROP_MEDIA_ICON_NAME, n);

    pa_source_output_update_proplist(u->source_output, PA_UPDATE_REPLACE, p);
    pa_proplist_free(p);

    if (pa_sink_get_state(dest) == PA_SINK_SUSPENDED)
        pa_source_output_cork(u->source_output, true);
    else
        pa_source_output_cork(u->source_output, false);

    update_adjust_timer(u);
}

/* Called from main context */
int pa_source_output_move_to(pa_source_output *o, pa_source *dest, pa_bool_t save) {
    int r;

    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();
    pa_assert(PA_SOURCE_OUTPUT_IS_LINKED(o->state));
    pa_assert(o->source);
    pa_source_assert_ref(dest);

    if (dest == o->source)
        return 0;

    if (!pa_source_output_may_move_to(o, dest))
        return -PA_ERR_NOTSUPPORTED;

    pa_source_output_ref(o);

    if ((r = pa_source_output_start_move(o)) < 0) {
        pa_source_output_unref(o);
        return r;
    }

    if ((r = pa_source_output_finish_move(o, dest, save)) < 0) {
        pa_source_output_fail_move(o);
        pa_source_output_unref(o);
        return r;
    }

    pa_source_output_unref(o);

    return 0;
}

/* Called from main context */
void pa_source_output_send_event(pa_source_output *o, const char *event, pa_proplist *data) {
    pa_proplist *pl = NULL;
    pa_source_output_send_event_hook_data hook_data;

    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();
    pa_assert(event);

    if (!o->send_event)
        return;

    if (!data)
        data = pl = pa_proplist_new();

    hook_data.source_output = o;
    hook_data.data = data;
    hook_data.event = event;

    if (pa_hook_fire(&o->core->hooks[PA_CORE_HOOK_SOURCE_OUTPUT_SEND_EVENT], &hook_data) < 0)
        goto finish;

    o->send_event(o, event, data);

finish:
    if (pl)
        pa_proplist_free(pl);
}

/* Called from main context */
int pa_source_output_start_move(pa_source_output *o) {
    pa_source *origin;
    int r;

    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();
    pa_assert(PA_SOURCE_OUTPUT_IS_LINKED(o->state));
    pa_assert(o->source);

    if (!pa_source_output_may_move(o))
        return -PA_ERR_NOTSUPPORTED;

    if ((r = pa_hook_fire(&o->core->hooks[PA_CORE_HOOK_SOURCE_OUTPUT_MOVE_START], o)) < 0)
        return r;

    origin = o->source;

    pa_idxset_remove_by_data(o->source->outputs, o, NULL);

    if (pa_source_output_get_state(o) == PA_SOURCE_OUTPUT_CORKED)
        pa_assert_se(origin->n_corked-- >= 1);

    pa_assert_se(pa_asyncmsgq_send(o->source->asyncmsgq, PA_MSGOBJECT(o->source), PA_SOURCE_MESSAGE_REMOVE_OUTPUT, o, 0, NULL) == 0);

    pa_source_update_status(o->source);
    o->source = NULL;

    pa_source_output_unref(o);

    return 0;
}

/* Called from main thread */
static void sink_input_moving_cb(pa_sink_input *i, pa_sink *dest) {
    struct userdata *u;
    char *output_description;
    const char *n;

    if (!dest)
        return;

    pa_sink_input_assert_ref(i);
    pa_assert_ctl_context();
    pa_assert_se(u = i->userdata);

    output_description = pa_sprintf_malloc("Loopback to %s",
                                           pa_strnull(pa_proplist_gets(dest->proplist, PA_PROP_DEVICE_DESCRIPTION)));
    pa_source_output_set_property(u->source_output, PA_PROP_MEDIA_NAME, output_description);
    pa_xfree(output_description);

    if ((n = pa_proplist_gets(dest->proplist, PA_PROP_DEVICE_ICON_NAME)))
        pa_source_output_set_property(u->source_output, PA_PROP_MEDIA_ICON_NAME, n);

    if (pa_sink_get_state(dest) == PA_SINK_SUSPENDED)
        pa_source_output_cork(u->source_output, true);
    else
        pa_source_output_cork(u->source_output, false);

    update_adjust_timer(u);
}

/* Called from main context */
void pa_source_output_cork(pa_source_output *o, pa_bool_t b) {
    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();
    pa_assert(PA_SOURCE_OUTPUT_IS_LINKED(o->state));

    source_output_set_state(o, b ? PA_SOURCE_OUTPUT_CORKED : PA_SOURCE_OUTPUT_RUNNING);
}

/* Called from main thread */
static void source_output_moving_cb(pa_source_output *o, pa_source *dest) {
    struct userdata *u;

    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();
    pa_assert_se(u = o->userdata);

    if (dest) {
        pa_source_set_asyncmsgq(u->source, dest->asyncmsgq);
        pa_source_update_flags(u->source, PA_SOURCE_LATENCY|PA_SOURCE_DYNAMIC_LATENCY, dest->flags);
    } else
        pa_source_set_asyncmsgq(u->source, NULL);

    if (u->auto_desc && dest) {
        const char *k;
        pa_proplist *pl;

        pl = pa_proplist_new();
        k = pa_proplist_gets(dest->proplist, PA_PROP_DEVICE_DESCRIPTION);
        pa_proplist_setf(pl, PA_PROP_DEVICE_DESCRIPTION, "Remapped %s", k ? k : dest->name);

        pa_source_update_proplist(u->source, PA_UPDATE_REPLACE, pl);
        pa_proplist_free(pl);
    }
}

/* Called from main context */
static void teardown(struct userdata *u) {
    pa_assert(u);
    pa_assert_ctl_context();

    u->adjust_time = 0;
    enable_adjust_timer(u, false);

    /* Handling the asyncmsgq between the source output and the sink input
     * requires some care. When the source output is unlinked, nothing needs
     * to be done for the asyncmsgq, because the source output is the sending
     * end. But when the sink input is unlinked, we should ensure that the
     * asyncmsgq is emptied, because the messages in the queue hold references
     * to the sink input. Also, we need to ensure that new messages won't be
     * written to the queue after we have emptied it.
     *
     * Emptying the queue can be done in the state_changed() callback of the
     * sink input, when the new state is "unlinked".
     *
     * Preventing new messages from being written to the queue can be achieved
     * by unlinking the source output before unlinking the sink input. There
     * are no other writers for that queue, so this is sufficient. */

    if (u->source_output) {
        pa_source_output_unlink(u->source_output);
        pa_source_output_unref(u->source_output);
        u->source_output = NULL;
    }

    if (u->sink_input) {
        pa_sink_input_unlink(u->sink_input);
        pa_sink_input_unref(u->sink_input);
        u->sink_input = NULL;
    }
}

/* Called from main context */
pa_usec_t pa_source_output_set_requested_latency(pa_source_output *o, pa_usec_t usec) {
    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();

    if (PA_SOURCE_OUTPUT_IS_LINKED(o->state) && o->source) {
        pa_assert_se(pa_asyncmsgq_send(o->source->asyncmsgq, PA_MSGOBJECT(o), PA_SOURCE_OUTPUT_MESSAGE_SET_REQUESTED_LATENCY, &usec, 0, NULL) == 0);
        return usec;
    }

    /* If this source output is not realized yet or is being moved, we
     * have to touch the thread info data directly */

    if (o->source) {
        if (!(o->source->flags & PA_SOURCE_DYNAMIC_LATENCY))
            usec = pa_source_get_fixed_latency(o->source);

        if (usec != (pa_usec_t) -1) {
            pa_usec_t min_latency, max_latency;
            pa_source_get_latency_range(o->source, &min_latency, &max_latency);
            usec = PA_CLAMP(usec, min_latency, max_latency);
        }
    }

    o->thread_info.requested_source_latency = usec;

    return usec;
}

/* Called from main context */
void pa_source_output_kill(pa_source_output*o) {
    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();
    pa_assert(PA_SOURCE_OUTPUT_IS_LINKED(o->state));

    o->kill(o);
}

/* Called from main context */
static void adjust_rates(struct userdata *u) {
    size_t buffer, fs;
    uint32_t old_rate, base_rate, new_rate;
    pa_usec_t buffer_latency;

    pa_assert(u);
    pa_assert_ctl_context();

    pa_asyncmsgq_send(u->source_output->source->asyncmsgq, PA_MSGOBJECT(u->source_output), SOURCE_OUTPUT_MESSAGE_LATENCY_SNAPSHOT, NULL, 0, NULL);
    pa_asyncmsgq_send(u->sink_input->sink->asyncmsgq, PA_MSGOBJECT(u->sink_input), SINK_INPUT_MESSAGE_LATENCY_SNAPSHOT, NULL, 0, NULL);

    buffer =
        u->latency_snapshot.sink_input_buffer +
        u->latency_snapshot.source_output_buffer;

    if (u->latency_snapshot.recv_counter <= u->latency_snapshot.send_counter)
        buffer += (size_t) (u->latency_snapshot.send_counter - u->latency_snapshot.recv_counter);
    else
        buffer += PA_CLIP_SUB(buffer, (size_t) (u->latency_snapshot.recv_counter - u->latency_snapshot.send_counter));

    buffer_latency = pa_bytes_to_usec(buffer, &u->sink_input->sample_spec);

    pa_log_debug("Loopback overall latency is %0.2f ms + %0.2f ms + %0.2f ms = %0.2f ms",
                (double) u->latency_snapshot.sink_latency / PA_USEC_PER_MSEC,
                (double) buffer_latency / PA_USEC_PER_MSEC,
                (double) u->latency_snapshot.source_latency / PA_USEC_PER_MSEC,
                ((double) u->latency_snapshot.sink_latency + buffer_latency + u->latency_snapshot.source_latency) / PA_USEC_PER_MSEC);

    pa_log_debug("Should buffer %zu bytes, buffered at minimum %zu bytes",
                u->latency_snapshot.max_request*2,
                u->latency_snapshot.min_memblockq_length);

    fs = pa_frame_size(&u->sink_input->sample_spec);
    old_rate = u->sink_input->sample_spec.rate;
    base_rate = u->source_output->sample_spec.rate;

    if (u->latency_snapshot.min_memblockq_length < u->latency_snapshot.max_request*2)
        new_rate = base_rate - (((u->latency_snapshot.max_request*2 - u->latency_snapshot.min_memblockq_length) / fs) *PA_USEC_PER_SEC)/u->adjust_time;
    else
        new_rate = base_rate + (((u->latency_snapshot.min_memblockq_length - u->latency_snapshot.max_request*2) / fs) *PA_USEC_PER_SEC)/u->adjust_time;

    if (new_rate < (uint32_t) (base_rate*0.8) || new_rate > (uint32_t) (base_rate*1.25)) {
        pa_log_warn("Sample rates too different, not adjusting (%u vs. %u).", base_rate, new_rate);
        new_rate = base_rate;
    } else {
        if (base_rate < new_rate + 20 && new_rate < base_rate + 20)
          new_rate = base_rate;
        /* Do the adjustment in small steps; 2‰ can be considered inaudible */
        if (new_rate < (uint32_t) (old_rate*0.998) || new_rate > (uint32_t) (old_rate*1.002)) {
            pa_log_info("New rate of %u Hz not within 2‰ of %u Hz, forcing smaller adjustment", new_rate, old_rate);
            new_rate = PA_CLAMP(new_rate, (uint32_t) (old_rate*0.998), (uint32_t) (old_rate*1.002));
        }
    }

    pa_sink_input_set_rate(u->sink_input, new_rate);
    pa_log_debug("[%s] Updated sampling rate to %lu Hz.", u->sink_input->sink->name, (unsigned long) new_rate);

    pa_core_rttime_restart(u->core, u->time_event, pa_rtclock_now() + u->adjust_time);
}

/* Called from main thread */
static pa_bool_t source_output_may_move_to_cb(pa_source_output *o, pa_source *dest) {
    struct userdata *u;

    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();
    pa_assert_se(u = o->userdata);

    return dest != u->sink_input->sink->monitor_source;
}

/* Called from main thread */
static void source_output_kill_cb(pa_source_output *o) {
    struct userdata *u;

    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();
    pa_assert_se(u = o->userdata);

    teardown(u);
    pa_module_unload_request(u->module, TRUE);
}

/* Called from main thread */
static void sink_input_kill_cb(pa_sink_input *i) {
    struct userdata *u;

    pa_sink_input_assert_ref(i);
    pa_assert_ctl_context();
    pa_assert_se(u = i->userdata);

    teardown(u);
    pa_module_unload_request(u->module, TRUE);
}

/* Called from main thread */
static void sink_input_suspend_cb(pa_sink_input *i, pa_bool_t suspended) {
    struct userdata *u;

    pa_sink_input_assert_ref(i);
    pa_assert_ctl_context();
    pa_assert_se(u = i->userdata);

    pa_source_output_cork(u->source_output, suspended);

    update_adjust_timer(u);
}

/* Called from main thread */
void pa_source_output_update_proplist(pa_source_output *o, pa_update_mode_t mode, pa_proplist *p) {
    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();

    if (p)
        pa_proplist_update(o->proplist, mode, p);

    if (PA_SOURCE_OUTPUT_IS_LINKED(o->state)) {
        pa_hook_fire(&o->core->hooks[PA_CORE_HOOK_SOURCE_OUTPUT_PROPLIST_CHANGED], o);
        pa_subscription_post(o->core, PA_SUBSCRIPTION_EVENT_SOURCE_OUTPUT|PA_SUBSCRIPTION_EVENT_CHANGE, o->index);
    }
}

/* Called from main context */
static void update_n_corked(pa_source_output *o, pa_source_output_state_t state) {
    pa_assert(o);
    pa_assert_ctl_context();

    if (!o->source)
        return;

    if (o->state == PA_SOURCE_OUTPUT_CORKED && state != PA_SOURCE_OUTPUT_CORKED)
        pa_assert_se(o->source->n_corked -- >= 1);
    else if (o->state != PA_SOURCE_OUTPUT_CORKED && state == PA_SOURCE_OUTPUT_CORKED)
        o->source->n_corked++;
}

/* Called from main thread */
static bool sink_input_may_move_to_cb(pa_sink_input *i, pa_sink *dest) {
    struct userdata *u;

    pa_sink_input_assert_ref(i);
    pa_assert_ctl_context();
    pa_assert_se(u = i->userdata);

    if (!u->source_output || !u->source_output->source)
        return true;

    return dest != u->source_output->source->monitor_of;
}

/* Called from main context */
pa_bool_t pa_source_output_may_move(pa_source_output *o) {
    pa_source_output_assert_ref(o);
    pa_assert_ctl_context();
    pa_assert(PA_SOURCE_OUTPUT_IS_LINKED(o->state));

    if (o->flags & PA_SOURCE_OUTPUT_DONT_MOVE)
        return FALSE;

    if (o->direct_on_input)
        return FALSE;

    return TRUE;
}

/* Called from main context */
void pa_source_output_unlink(pa_source_output*o) {
    pa_bool_t linked;
    pa_assert(o);
    pa_assert_ctl_context();

    /* See pa_sink_unlink() for a couple of comments how this function
     * works */

    pa_source_output_ref(o);

    linked = PA_SOURCE_OUTPUT_IS_LINKED(o->state);

    if (linked)
        pa_hook_fire(&o->core->hooks[PA_CORE_HOOK_SOURCE_OUTPUT_UNLINK], o);

    if (o->direct_on_input)
        pa_idxset_remove_by_data(o->direct_on_input->direct_outputs, o, NULL);

    pa_idxset_remove_by_data(o->core->source_outputs, o, NULL);

    if (o->source)
        if (pa_idxset_remove_by_data(o->source->outputs, o, NULL))
            pa_source_output_unref(o);

    if (o->client)
        pa_idxset_remove_by_data(o->client->source_outputs, o, NULL);

    update_n_corked(o, PA_SOURCE_OUTPUT_UNLINKED);
    o->state = PA_SOURCE_OUTPUT_UNLINKED;

    if (linked && o->source)
        if (o->source->asyncmsgq)
            pa_assert_se(pa_asyncmsgq_send(o->source->asyncmsgq, PA_MSGOBJECT(o->source), PA_SOURCE_MESSAGE_REMOVE_OUTPUT, o, 0, NULL) == 0);

    reset_callbacks(o);

    if (linked) {
        pa_subscription_post(o->core, PA_SUBSCRIPTION_EVENT_SOURCE_OUTPUT|PA_SUBSCRIPTION_EVENT_REMOVE, o->index);
        pa_hook_fire(&o->core->hooks[PA_CORE_HOOK_SOURCE_OUTPUT_UNLINK_POST], o);
    }

    if (o->source) {
        pa_source_update_status(o->source);
        o->source = NULL;
    }

    pa_core_maybe_vacuum(o->core);

    pa_source_output_unref(o);
}