/**
 * Frontend Date Filtering Utilities for D-1 Logic
 * Mirrors backend dateUtils for client-side awareness
 */

const CUTOFF_HOUR = 17;
const WIB_TIME_ZONE = 'Asia/Jakarta';

type WibDateParts = {
  year: number;
  month: number;
  day: number;
  hour: number;
  minute: number;
  second: number;
};

function getWibDateParts(referenceDate?: Date): WibDateParts {
  const now = referenceDate || new Date();

  const formatter = new Intl.DateTimeFormat('en-CA', {
    timeZone: WIB_TIME_ZONE,
    year: 'numeric',
    month: '2-digit',
    day: '2-digit',
    hour: '2-digit',
    minute: '2-digit',
    second: '2-digit',
    hour12: false,
  });

  const parts = formatter.formatToParts(now);
  const lookup = Object.fromEntries(
    parts.filter((part) => part.type !== 'literal').map((part) => [part.type, part.value])
  ) as Record<string, string>;

  return {
    year: Number(lookup.year),
    month: Number(lookup.month),
    day: Number(lookup.day),
    hour: Number(lookup.hour),
    minute: Number(lookup.minute),
    second: Number(lookup.second),
  };
}

function createLocalDateFromWibParts(parts: WibDateParts): Date {
  const date = new Date(
    parts.year,
    parts.month - 1,
    parts.day,
    parts.hour,
    parts.minute,
    parts.second
  );
  date.setMilliseconds(0);
  return date;
}

/**
 * Get current date/time in WIB (Asia/Jakarta, UTC+7) timezone
 * @param referenceDate - Optional reference date for testing
 * @returns Current date in WIB
 */
export function getCurrentWibDate(referenceDate?: Date): Date {
  return createLocalDateFromWibParts(getWibDateParts(referenceDate));
}

/**
 * Check if current WIB time is before 17:00
 * @param referenceDate - Optional reference date for testing
 * @returns True if before cutoff, false otherwise
 */
export function shouldUsePreviousDay(referenceDate?: Date): boolean {
  return getWibDateParts(referenceDate).hour < CUTOFF_HOUR;
}

/**
 * Get effective date for data queries (D-1 or today)
 * @param referenceDate - Optional reference date for testing
 * @returns Effective date for queries
 */
export function getEffectiveDate(referenceDate?: Date): Date {
  const wibParts = getWibDateParts(referenceDate);
  const wibToday = createLocalDateFromWibParts(wibParts);

  if (shouldUsePreviousDay(referenceDate)) {
    // Return D-1 (previous day)
    const yesterday = new Date(wibToday);
    yesterday.setDate(yesterday.getDate() - 1);
    return yesterday;
  }

  return wibToday;
}

/**
 * Calculate effective cycle day with D-1 adjustment
 * @param cycleStartDate - Cycle start date
 * @param referenceDate - Optional reference date for testing
 * @returns Effective cycle day (0-indexed)
 */
export function getEffectiveCycleDay(cycleStartDate: Date | string, referenceDate?: Date): number {
  const effectiveDate = getEffectiveDate(referenceDate);
  const startDate = new Date(cycleStartDate);

  // Reset hours to compare dates only
  effectiveDate.setHours(0, 0, 0, 0);
  startDate.setHours(0, 0, 0, 0);

  const diffMs = effectiveDate.getTime() - startDate.getTime();

  // Return -1 if effective date is before cycle start
  if (diffMs < 0) {
    return -1;
  }

  const dayOfCycle = Math.floor(diffMs / (1000 * 60 * 60 * 24));
  return dayOfCycle;
}

/**
 * Format date as YYYY-MM-DD
 * @param date - Date object to format
 * @returns Date in YYYY-MM-DD format
 */
export function formatDateForDb(date: Date): string {
  const year = date.getFullYear();
  const month = String(date.getMonth() + 1).padStart(2, '0');
  const day = String(date.getDate()).padStart(2, '0');
  return `${year}-${month}-${day}`;
}

/**
 * Format effective date label with disclaimer if D-1 active
 * @param date - Date to format
 * @param referenceDate - Optional reference date for testing
 * @returns Formatted date string with optional disclaimer
 */
export function formatEffectiveDateLabel(date: Date, referenceDate?: Date): string {
  const monthNames = [
    'Januari',
    'Februari',
    'Maret',
    'April',
    'Mei',
    'Juni',
    'Juli',
    'Agustus',
    'September',
    'Oktober',
    'November',
    'Desember',
  ];

  const day = date.getDate();
  const month = monthNames[date.getMonth()];
  const year = date.getFullYear();
  const baseLabel = `${day} ${month} ${year}`;

  if (shouldUsePreviousDay(referenceDate)) {
    return `${baseLabel} (Data Hari Kemarin)`;
  }

  return baseLabel;
}

/**
 * Get adjusted date range for API queries (applies D-1 filter if needed)
 * @param startDate - Start date string (YYYY-MM-DD)
 * @param endDate - End date string (YYYY-MM-DD)
 * @param referenceDate - Optional reference date for testing
 * @returns Adjusted start and end dates
 */
export function getAdjustedDateRange(
  startDate: string,
  endDate: string,
  referenceDate?: Date
): { start: string; end: string } {
  // Only adjust if querying a single day and before cutoff
  if (startDate === endDate && shouldUsePreviousDay(referenceDate)) {
    const adjusted = getEffectiveDate(referenceDate);
    const adjustedStr = formatDateForDb(adjusted);
    return { start: adjustedStr, end: adjustedStr };
  }

  return { start: startDate, end: endDate };
}

type CycleEstimasiPanenInput = {
  startDate?: Date | string | null;
  endDate?: Date | string | null;
  totalDays?: number | null;
};

/**
 * Estimasi Panen calendar date: endDate, or startDate + (totalDays - 1).
 */
export function getEstimasiPanenDate(cycle: CycleEstimasiPanenInput): Date | null {
  if (cycle.endDate) {
    const end = new Date(cycle.endDate);
    if (!Number.isFinite(end.getTime())) return null;
    end.setHours(0, 0, 0, 0);
    return end;
  }

  if (!cycle.startDate) return null;
  const start = new Date(cycle.startDate);
  if (!Number.isFinite(start.getTime())) return null;
  start.setHours(0, 0, 0, 0);
  start.setDate(start.getDate() + Math.max(0, (cycle.totalDays || 1) - 1));
  return start;
}

/**
 * Inclusive end-of-day timestamp (local) for Estimasi Panen.
 * IoT readings with updatedAt after this should not be shown.
 */
export function getEstimasiPanenEndMs(cycle: CycleEstimasiPanenInput): number | null {
  const panenDate = getEstimasiPanenDate(cycle);
  if (!panenDate) return null;
  panenDate.setHours(23, 59, 59, 999);
  return panenDate.getTime();
}