#define pr_fmt(fmt) "[hui] " fmt

#include "events.h"
#include "hui_internal.h"
#include "log.h"

#include <linux/workqueue.h>
#include <linux/slab.h>

#include <avm/sammel/simple_proc.h>
#include <avm/event/event.h>

#define DEFINE_EVENT_STATE(_name, ...) __VA_ARGS__
#define DEFINE_EVENT(_name, _id, ...)                            \
	const struct avm_hui_event_info __event_info_##_name = { \
		.id = _id,                                       \
		.name = #_name,                                  \
	};
#define DEFINE_EVENT_RAW(_name, _id, ...) DEFINE_EVENT(_name, _id)
#define DEFINE_EVENT_RAW_INTERNAL(_name, ...) DEFINE_EVENT(_name, -1)
#define _ALL_EVENTS
#include <avm/hui/_events.h>

const struct avm_hui_event_info *_avm_hui_all_events[] = {
#define DEFINE_EVENT_STATE(_name, ...) __VA_ARGS__
#define DEFINE_EVENT(_name, _id, ...) &__event_info_##_name,
#define DEFINE_EVENT_RAW(_name, _id, ...) DEFINE_EVENT(_name, _id)
#define DEFINE_EVENT_RAW_INTERNAL(_name, ...) DEFINE_EVENT(_name, -1)
#define _ALL_EVENTS
#include <avm/hui/_events.h>
	NULL,
};

#define DEFINE_EVENT(_name, _id, ...) \
	[_name] = { .name = #_name, .event_id = _id, __VA_ARGS__ },
#define DEFINE_EVENT_STATE(_name, ...)                                  \
	static const struct event_member_def                            \
		__event_def_##_name[_name##_invalid] = { __VA_ARGS__ }; \
	struct event __event_##_name = {                                \
		.name = #_name,                                         \
		.max_state = _name##_invalid,                           \
		.def = __event_def_##_name,                             \
		.raw_event_id = 0,                                      \
	};
#define DEFINE_EVENT_RAW(_name, _id, _default)          \
	struct event __event_##_name = {                \
		.name = #_name,                         \
		.max_state = 0,                         \
		.def = NULL,                            \
		.raw_event_id = _id,                    \
		.current_value = ATOMIC_INIT(_default), \
		.pending_value = ATOMIC_INIT(_default), \
		.callback = NULL,                       \
	};
#define DEFINE_EVENT_RAW_INTERNAL(_name, ...) DEFINE_EVENT_RAW(_name, -1, 0)
#include <avm/hui/_events.h>

static struct event *events_list[] = {
#define DEFINE_EVENT_STATE(_name, ...) &__event_##_name,
#define DEFINE_EVENT_RAW(_name, ...) &__event_##_name,
#define DEFINE_EVENT_RAW_INTERNAL(_name, ...) &__event_##_name,
#include <avm/hui/_events.h>

	NULL,
};

static inline void events_handle_timeout(timer_callback j)
{
	pr_debug("Events timeout reached\n");
	hui_schedule_update();
}

static HUI_DEFINE_TIMER(events_timer, events_handle_timeout);

/*
 * This function is the main entry point for led events delivered via avm_event. It
 * will try to find the corresponding event group or raw event.
 *
 * If the new event is the same as currently set, the function will short-circuit and
 * no further processing done. Transient events are exempt from this.
 *
 * The new event value will be stored as pending and a hui update cycle is
 * requested. During the update cycle the pending event will update the event state.
 */
static inline void event_handler(void *ctx, unsigned char *buf,
				 unsigned int len)
{
	int i, j;
	int event_id, value;
	struct _avm_event_led_status *incoming_event;

	if (len < sizeof(struct _avm_event_led_status))
		return;

	incoming_event = (void *)buf;
	if (incoming_event->header.id != avm_event_id_led_status)
		return;

	event_id = incoming_event->led;
	value = incoming_event->state;

	for (i = 0; events_list[i] != NULL; i++) {
		struct event *event = events_list[i];

		if (event->def) {
			for (j = 0; j < event->max_state; j++) {
				if (event->def[j].event_id != event_id)
					continue;

				if (!event_is_transient(event) &&
				    event_get_value(event) == j &&
				    event_get_pending_value(event) == j)
					return;

				pr_debug(
					"Got event state %s with member %s (%d) and value %d\n",
					event->name, event->def[j].name,
					event_id, value);
				atomic_set(&event->pending_value, j);
				hui_log_event(event, j);
				hui_schedule_update();
				return;
			}
		} else if (event->raw_event_id == event_id) {
			if (!event_is_transient(event) &&
			    event_get_value(event) == value)
				return;

			pr_debug("Got raw event %s with value %d\n",
				 event->name, value);
			atomic_set(&event->pending_value, value);
			hui_log_event(event, value);
			hui_schedule_update();
			return;
		}
	}
	pr_info("Unhandled event %d with value %d\n", event_id, value);
	hui_log_unknown_event(event_id, value);
}

static inline void events_expire(void)
{
	int i;

	for (i = 0; events_list[i] != NULL; i++) {
		struct event *event = events_list[i];

		// No member defs, can not have a timeout
		if (!event->def)
			continue;

		// No timeout configured
		if (!event->timeout_setup)
			continue;

		pr_debug("Look at timeout for %s: %ld <> %ld\n", event->name,
			 event->timeout, jiffies);

		// We expired
		if (time_is_before_eq_jiffies(event->timeout)) {
			int value = event_get_value(event);
			int new = event->def[value].timeout.next;

			pr_debug("Expire timeout %s: %s (%d) -> %s (%d)\n",
				 event->name, event->def[value].name, value,
				 event->def[new].name, new);
			atomic_set(&event->pending_value, new);
			hui_log_event(event, new);
		}
	}
}

static inline void events_update_values(void)
{
	int i;

	for (i = 0; events_list[i] != NULL; i++) {
		struct event *event = events_list[i];
		int old = event_get_value(event);
		int new = event_get_pending_value(event);

		if (!event_is_transient(event) && new == old)
			continue;

		if (event->def)
			pr_debug("Update %s: %s (%d) -> %s (%d)\n", event->name,
				 event->def[old].name, old,
				 event->def[new].name, new);
		else if (event_is_transient(event))
			pr_debug("Got %s with %d\n", event->name, new);
		else
			pr_debug("Update %s: %d -> %d\n", event->name, old,
				 new);

		atomic_set(&event->current_value, new);
		event->timeout = 0;
		event->timeout_setup = 0;
		if (event->callback)
			event->callback(event, old, new);
	}
}

static inline unsigned long min_jiffies(unsigned long a, unsigned long b)
{
	if (a == MAX_JIFFY_OFFSET)
		return b;

	if (b == MAX_JIFFY_OFFSET)
		return a;

	// TODO: is this correct?
	return time_before(a, b) ? a : b;
}

static inline void events_setup_timeout(void)
{
	int i;
	unsigned long min = MAX_JIFFY_OFFSET;

	for (i = 0; events_list[i] != NULL; i++) {
		struct event *event = events_list[i];
		const struct event_member_def *def;

		// Not a state event
		if (!event->def)
			continue;

		def = event->def + event_get_value(event);

		// Is this state supposed to have an timeout
		if (def->timeout.ms == 0)
			continue;

		// No timeout setup, do so
		if (!event->timeout_setup) {
			event->timeout =
				jiffies + msecs_to_jiffies(def->timeout.ms);
			event->timeout_setup = 1;
			pr_debug("Setup timeout for %s: expires=%ld\n",
				 event->name, event->timeout);
		}

		min = min_jiffies(min, event->timeout);
	}

	// No timeouts, no need to reschedule
	if (min == MAX_JIFFY_OFFSET)
		return;

	pr_debug("Schedule timeout for %ld\n", min + 1);
	mod_timer(&events_timer, min + 1);
}

void events_update(void)
{
	events_expire();
	events_update_values();
	events_setup_timeout();
}

static void proc_event_state(struct seq_file *seq, void *context)
{
	int i;
	mutex_lock(&hui_update_mutex);

	for (i = 0; events_list[i] != NULL; i++) {
		struct event *event = events_list[i];
		int value = event_get_value(event);

		if (event_is_transient(event))
			continue;

		if (event->def) {
			seq_printf(seq, "%s: %s (%d)\n", event->name,
				   event->def[value].name, value);
		} else {
			seq_printf(seq, "%s(%d): %d\n", event->name,
				   event->raw_event_id, value);
		}
	}

	mutex_unlock(&hui_update_mutex);
}

void *event_sink;
void *event_source;

int _avm_hui_send_event(int version, enum _led_event event_id,
			       unsigned int value)
{
	struct _avm_event_led_status *event;
	int size = sizeof(struct _avm_event_led_status);

	if (hui_bare_handle_event(event_id, value))
		return 0;

	event = kzalloc(size, GFP_ATOMIC);
	if (!event)
		return -ENOMEM;

	event->header.id = avm_event_id_led_status;
	event->led = event_id;
	event->state = value;

	return avm_event_source_trigger(event_source, avm_event_id_led_status,
					size, event);
}

static void brightness_cb(struct event *event, int old, int new)
{
	if (new > 100)
		new = 100;

	hui_kobj->brightness = new;
}

static void ab_cb(struct event *event, int old, int new)
{
	int val = event_get_value(ab);

	if (!new)
		return;
	atomic_set(&event->current_value, 0);
	atomic_set(&event->pending_value, 0);

	if (event == ab_onhook || event == ab_fehler)
		val &= ~new;
	else
		val |= new;

	if (val != event_get_value(ab)) {
		atomic_set(&ab->current_value, val);
		atomic_set(&ab->pending_value, val);

		hui_log_event(ab, val);
	}
}

void events_init(void)
{
	struct _avm_event_id_mask id_mask;

	add_simple_proc_file("avm/hui/event_state", NULL, proc_event_state,
			     NULL);

	avm_event_build_id_mask(&id_mask, 1, avm_event_id_led_status);
	event_sink =
		avm_event_sink_register("hui", &id_mask, event_handler, NULL);
	event_source = avm_event_source_register("hui", &id_mask, NULL, NULL);

#if IS_ENABLED(CONFIG_AVM_LED_EVENTS)
	led_event_action = _avm_hui_send_event;
#endif

	event_set_callback(dim_brightness, brightness_cb);

	event_set_callback(ab_onhook, ab_cb);
	ab_onhook->flags |= EVENT_FLAG_TRANSIENT;
	event_set_callback(ab_fehler, ab_cb);
	ab_fehler->flags |= EVENT_FLAG_TRANSIENT;
	event_set_callback(ab_offhook, ab_cb);
	ab_offhook->flags |= EVENT_FLAG_TRANSIENT;
	event_set_callback(ab_active, ab_cb);
	ab_active->flags |= EVENT_FLAG_TRANSIENT;
}

void events_exit(void)
{
#if IS_ENABLED(CONFIG_AVM_LED_EVENTS)
	led_event_action = NULL;
#endif

	if (event_sink)
		avm_event_sink_release(event_sink);
	if (event_source)
		avm_event_source_release(event_source);
}

const char *avm_hui_get_event_name(enum _led_event event_id)
{
	int i;
	const struct avm_hui_event_info *info;

	foreach_avm_hui_event(i, info) {
		if (info->id == event_id)
			return info->name;
	}

	return NULL;
}

const struct avm_hui_event_info *avm_hui_get_info_by_id(enum _led_event id)
{
	int i;
	const struct avm_hui_event_info *info;

	foreach_avm_hui_event(i, info) {
		if (info->id == id)
			return info;
	}

	return NULL;
}

const struct avm_hui_event_info *avm_hui_get_info_by_name(const char *name)
{
	int i;
	const struct avm_hui_event_info *info;

	foreach_avm_hui_event(i, info) {
		if (strcmp(info->name, name) == 0)
			return info;
	}

	return NULL;
}