/**
 * TrackerMap
 * Copyright (C) 2021-2022  Iván Ávalos <avalos@disroot.org>, Henoch Ojeda <imhenoch@protonmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package mx.trackermap.TrackerMap.utils

import kotlinx.coroutines.DelicateCoroutinesApi
import kotlinx.datetime.*

@DelicateCoroutinesApi
class ReportDates {
    enum class ReportPeriod {
        TODAY, LAST_24, YESTERDAY, THIS_WEEK, LAST_7, THIS_MONTH, LAST_30
    }

    companion object {
        private fun formatDateTime(dateTime: LocalDateTime, timezone: TimeZone) =
            dateTime.toInstant(timezone).toString()

        fun getDates(period: ReportPeriod): Pair<String, String> {
            val timezone = TimeZone.currentSystemDefault()
            val clock = Clock.System
            val instant = clock.now()
            val dateTime = instant.toLocalDateTime(timezone)
            val date = dateTime.date

            var currentDate: LocalDateTime? = null
            var previousDate: LocalDateTime? = null
            when (period) {
                ReportPeriod.TODAY -> {
                    previousDate = date.atTime(0, 0)
                    currentDate = dateTime
                }
                ReportPeriod.LAST_24 -> {
                    previousDate = instant
                        .minus(1, DateTimeUnit.DAY, timezone)
                        .toLocalDateTime(timezone)
                    currentDate = dateTime
                }
                ReportPeriod.YESTERDAY -> {
                    val yesterday = instant
                        .minus(1, DateTimeUnit.DAY, timezone)
                        .toLocalDateTime(timezone).date
                    previousDate = yesterday.atTime(0, 0)
                    currentDate = yesterday.atTime(23, 59)
                }
                ReportPeriod.THIS_WEEK -> {
                    previousDate = instant
                        .minus(date.dayOfWeek.isoDayNumber - 1, DateTimeUnit.DAY, timezone)
                        .toLocalDateTime(timezone).date
                        .atTime(0, 0)
                    currentDate = dateTime
                }
                ReportPeriod.LAST_7 -> {
                    previousDate = instant
                        .minus(1, DateTimeUnit.WEEK, timezone)
                        .toLocalDateTime(timezone).date
                        .atTime(0, 0)
                    currentDate = dateTime
                }
                ReportPeriod.THIS_MONTH -> {
                    previousDate = instant
                        .minus(date.dayOfMonth - 1, DateTimeUnit.DAY, timezone)
                        .toLocalDateTime(timezone).date
                        .atTime(0, 0)
                    currentDate = dateTime
                }
                ReportPeriod.LAST_30 -> {
                    previousDate = instant
                        .minus(1, DateTimeUnit.MONTH, timezone)
                        .toLocalDateTime(timezone).date
                        .atTime(0, 0)
                    currentDate = dateTime
                }
            }

            return Pair(
                formatDateTime(currentDate, timezone),
                formatDateTime(previousDate, timezone)
            )
        }
    }
}