export type TimePeriodUnit = 'day' | 'week' | 'month' | 'year' | 'custom'

export const timePeriodUnitOptions: { label: string; value: TimePeriodUnit }[] = [
    { label: '日', value: 'day' },
    { label: '周', value: 'week' },
    { label: '月', value: 'month' },
    { label: '年', value: 'year' },
    { label: '自定义', value: 'custom' }
]

const datePickerTypeMap: Record<TimePeriodUnit, 'date' | 'month' | 'year'> = {
    day: 'date',
    week: 'date',
    month: 'month',
    year: 'year',
    custom: 'date'
}

const datePickerFormatMap: Record<TimePeriodUnit, string> = {
    day: 'YYYY-MM-DD',
    week: 'YYYY-MM-DD',
    month: 'YYYY-MM',
    year: 'YYYY',
    custom: 'YYYY-MM-DD'
}

const padTimeValue = (value: number, length = 2) => String(value).padStart(length, '0')

export const formatTimePeriodDateTime = (date: Date) => {
    const year = date.getFullYear()
    const month = padTimeValue(date.getMonth() + 1)
    const day = padTimeValue(date.getDate())
    const hour = padTimeValue(date.getHours())
    const minute = padTimeValue(date.getMinutes())
    const second = padTimeValue(date.getSeconds())
    const millisecond = padTimeValue(date.getMilliseconds(), 3)

    return `${year}-${month}-${day} ${hour}:${minute}:${second}.${millisecond}`
}

export const getTimePeriodPickerType = (unit: TimePeriodUnit) => datePickerTypeMap[unit]

export const getTimePeriodPickerFormat = (unit: TimePeriodUnit) => datePickerFormatMap[unit]

export const resolveTimePeriodUnitLabel = (unit: TimePeriodUnit) => {
    return timePeriodUnitOptions.find(item => item.value === unit)?.label ?? ''
}

export const buildTimePeriodRange = (unit: TimePeriodUnit, date: Date): string[] => {
    const year = date.getFullYear()
    const month = date.getMonth()
    const day = date.getDate()

    if (unit === 'day') {
        return [
            formatTimePeriodDateTime(new Date(year, month, day, 0, 0, 0, 0)),
            formatTimePeriodDateTime(new Date(year, month, day, 23, 59, 59, 999))
        ]
    }

    if (unit === 'week') {
        const dayOfWeek = date.getDay()
        const mondayOffset = dayOfWeek === 0 ? -6 : 1 - dayOfWeek
        const weekStart = new Date(year, month, day + mondayOffset, 0, 0, 0, 0)
        const weekEnd = new Date(
            weekStart.getFullYear(),
            weekStart.getMonth(),
            weekStart.getDate() + 6,
            23,
            59,
            59,
            999
        )

        return [formatTimePeriodDateTime(weekStart), formatTimePeriodDateTime(weekEnd)]
    }

    if (unit === 'year') {
        return [
            formatTimePeriodDateTime(new Date(year, 0, 1, 0, 0, 0, 0)),
            formatTimePeriodDateTime(new Date(year, 11, 31, 23, 59, 59, 999))
        ]
    }

    return [
        formatTimePeriodDateTime(new Date(year, month, 1, 0, 0, 0, 0)),
        formatTimePeriodDateTime(new Date(year, month + 1, 0, 23, 59, 59, 999))
    ]
}

export const shiftTimePeriod = (unit: TimePeriodUnit, date: Date, offset: number) => {
    const nextDate = new Date(date)

    if (unit === 'day') {
        nextDate.setDate(nextDate.getDate() + offset)
        return nextDate
    }

    if (unit === 'year') {
        nextDate.setFullYear(nextDate.getFullYear() + offset)
        return nextDate
    }

    if (unit === 'week') {
        nextDate.setDate(nextDate.getDate() + offset * 7)
        return nextDate
    }

    // 月份切换以 1 日为锚点，避免 31 日切到短月份时发生日期溢出。
    nextDate.setDate(1)
    nextDate.setMonth(nextDate.getMonth() + offset)
    return nextDate
}