/*
 * SPDX-License-Identifier: AGPL-3.0-only
 * Copyright (c) Camden Dixie O'Brien
 */

#include "alarms.h"

#include "console.h"
#include "sound.h"
#include "time_manager.h"

#include "esp_log.h"
#include <stdbool.h>
#include <stdio.h>
#include <string.h>

#define TAG "Alarms"

typedef struct {
	bool set;
	Time time;
} Alarm;

typedef struct {
	const Alarm *alarm;
	Time end;
} ActiveAlarm;

static Alarm alarms[CONFIG_MAX_ALARMS];
static ActiveAlarm active[CONFIG_MAX_ALARMS];
static unsigned active_count;
static Time last_check;

static bool add_alarm(Time time)
{
	for (unsigned i = 0; i < CONFIG_MAX_ALARMS; ++i) {
		if (!alarms[i].set) {
			alarms[i].set = true;
			alarms[i].time = time;
			return true;
		}
	}
	return false;
}

static void remove_alarm(unsigned index)
{
	alarms[index].set = false;
}

static void activate(unsigned index, Time end)
{
	if (active_count == 0)
		sound_alert_on();

	active[active_count].alarm = &alarms[index];
	active[active_count].end = end;
	++active_count;

	ESP_LOGI(TAG, "Alarm %u activated", index);
}

static void dismiss(unsigned index)
{
	if (active_count == 1)
		sound_alert_off();

	for (unsigned i = index + 1; i < active_count; ++i)
		active[i - 1] = active[i];
	--active_count;

	ESP_LOGI(TAG, "Alarm %u dismissed", index);
}

static bool passed_since_last_check(Time time, const Time *now)
{
	return last_check.hour <= time.hour && time.hour <= now->hour
	    && last_check.minute <= time.minute && time.minute <= now->minute
	    && last_check.second <= time.second && time.second <= now->second;
}

static Time add_minutes(const Time *time, unsigned minutes)
{
	Time new_time = {
		.hour = time->hour,
		.minute = time->minute + minutes,
		.second = time->second,
	};

	if (new_time.minute >= 60) {
		new_time.minute %= 60;
		++new_time.hour;
	}

	return new_time;
}

static void check_alarms(const Time *now)
{
	for (unsigned i = 0; i < CONFIG_MAX_ALARMS; ++i) {
		if (!alarms[i].set)
			continue;
		if (passed_since_last_check(alarms[i].time, now))
			activate(i, add_minutes(now, CONFIG_ALERT_MINUTES));
	}

	for (unsigned i = 0; i != active_count; ++i) {
		if (passed_since_last_check(active[i].end, now))
			dismiss(i);
	}

	last_check = *now;
}

static int command_func(int argc, char **argv)
{
	if (argc == 1) {
		for (unsigned i = 0; i < CONFIG_MAX_ALARMS; ++i) {
			if (!alarms[i].set)
				continue;
			printf(
			    "[%2u] %02u:%02u\n", i, alarms[i].time.hour,
			    alarms[i].time.minute);
		}
		return 0;
	} else if (argc >= 3) {
		if (strcmp(argv[1], "add") == 0) {
			Time time = { .second = 0 };
			int n = sscanf(argv[2], "%02u:%02u", &time.hour, &time.minute);
			if (n != 2) {
				printf("Invalid time\n");
				return 1;
			}
			if (!add_alarm(time)) {
				printf("Max number of alarms already set.\n");
				return 1;
			}
			return 0;
		} else if (strcmp(argv[1], "remove") == 0) {
			unsigned index;
			int n = sscanf(argv[2], "%u", &index);
			if (n != 1 || !alarms[index].set) {
				printf("Invalid index\n");
				return 1;
			}
			remove_alarm(index);
			return 0;
		} else {
			printf("Unrecognised subcommand\n");
			return 1;
		}
	} else {
		printf("Invalid number of arguments\n");
		return 1;
	}
}

void alarms_init(void)
{
	memset(alarms, 0, sizeof(alarms));
	memset(active, 0, sizeof(active));
	active_count = 0;
	last_check = get_time();

	add_time_callback(check_alarms);

	console_register(
	    "alarms", "List, add and remove alarms",
	    "alarms OR alarms add <hh:mm> OR alarms remove <index>",
	    command_func);
}

void alarm_snooze(void)
{
}

void alarm_dismiss(void)
{
	if (active_count > 0)
		dismiss(0);
}