date.kt

fun main() {
    println("Now           : ${LocalDateTime.now()}")
    println("Start of Day  : ${LocalDateTime.now().startOfDay()}")
    println("End of Day    : ${LocalDateTime.now().endOfDay()}")
    println("Start of Month: ${LocalDateTime.now().startOfMonth()}")
    println("End of Month  : ${LocalDateTime.now().endOfMonth()}")
    println("Start of Year : ${LocalDateTime.now().startOfYear()}")
    println("End of Year   : ${LocalDateTime.now().endOfYear()}")
    println(
        LocalDateTime
            .dates(
                LocalDateTime.now().startOfMonth(),
                LocalDateTime.now().endOfMonth()
            ).map { it.dayOfMonth }
    )
    application {
        Window(
            onCloseRequest = ::exitApplication
        ) {
            val products = (1..1000).toList()
            LazyVerticalGrid(
                columns = GridCells.Fixed(5)
            ) {
                items(products) { product ->
                    Column(
                    ) {
                        Text(
                            modifier = Modifier
                                .padding(16.dp),
                            text = "Product $product",
                            overflow = TextOverflow.Ellipsis,
                            softWrap = false,
                        )
                        Divider()
                    }
                }
            }

        }
    }
}

fun Instant.toLocalDateTime(): LocalDateTime {
    return toLocalDateTime(TimeZone.currentSystemDefault())
}

fun LocalTime.Companion.min(): LocalTime {
    return LocalTime(0, 0)
}

fun LocalTime.Companion.max(): LocalTime {
    return LocalTime(23, 59, 59, 999_999_999)
}

fun LocalDateTime.Companion.now(): LocalDateTime {
    return Clock.System.now().toLocalDateTime()
}

fun LocalDateTime.Companion.dates(start: LocalDateTime, end: LocalDateTime): List<LocalDateTime> {
    var dates = mutableListOf<LocalDateTime>()
    var now = start
    while (now <= end) {
        dates.add(now)
        now = now.plus(1, DateTimeUnit.DAY)
    }
    return dates
}

fun LocalDateTime.toInstant(): Instant {
    return toInstant(TimeZone.currentSystemDefault())
}

fun LocalDateTime.plus(value: Long, unit: DateTimeUnit): LocalDateTime {
    return toInstant()
        .plus(value, unit, TimeZone.currentSystemDefault())
        .toLocalDateTime()
}

fun LocalDateTime.startOfDay(): LocalDateTime {
    return LocalDateTime(date, LocalTime.min())
}

fun LocalDateTime.endOfDay(): LocalDateTime {
    return LocalDateTime(date, LocalTime.max())
}

fun LocalDateTime.startOfMonth(): LocalDateTime {
    return LocalDateTime(
        LocalDate(year, month, 1),
        LocalTime.min()
    )
}

fun LocalDateTime.endOfMonth(): LocalDateTime {
    return plus(1, DateTimeUnit.MONTH)
        .startOfMonth()
        .plus(-1, DateTimeUnit.DAY)
        .endOfDay()
}

fun LocalDateTime.startOfYear(): LocalDateTime {
    return LocalDateTime(
        LocalDate(year, 1, 1),
        LocalTime.min()
    )
}

fun LocalDateTime.endOfYear(): LocalDateTime {
    return plus(1, DateTimeUnit.YEAR)
        .startOfYear()
        .plus(-1, DateTimeUnit.DAY)
        .endOfDay()
}