nanakshahi-ical/sgpc-nanakshahi/api-compatibility.js

Nanakshahi calendar iCal generator using official SGPC Jantri data with enhanced accuracy for Sikh religious observances.

/**
 * API Compatibility Layer
 * Provides nanakshahi-js compatible API for easy migration
 */

const dateConversion = require('./date-conversion')
const gurpurabData = require('./gurpurab-data')
const movableGurpurabs = require('./movable-gurpurabs')
const calendarData = require('./calendar-data')

/**
 * Get Nanakshahi date (compatible with nanakshahi-js.getNanakshahiDate)
 * @param {Date} gregorianDate - JavaScript Date object
 * @returns {Object} Nanakshahi date in English and Punjabi
 */
function getNanakshahiDate (gregorianDate = new Date()) {
  const nanakshahiDate = dateConversion.getNanakshahiDate(gregorianDate)

  if (!nanakshahiDate) {
    return null
  }

  // Format to match nanakshahi-js structure
  return {
    gregorianDate,
    englishDate: {
      month: nanakshahiDate.englishDate.month,
      monthName: nanakshahiDate.englishDate.monthName,
      date: nanakshahiDate.englishDate.date,
      year: nanakshahiDate.englishDate.year,
      day: nanakshahiDate.englishDate.day,
      dayShort: nanakshahiDate.englishDate.day.substring(0, 3)
    },
    punjabiDate: {
      month: toGurmukhiNum(nanakshahiDate.englishDate.month),
      monthName: nanakshahiDate.punjabiDate.monthName,
      date: toGurmukhiNum(nanakshahiDate.englishDate.date),
      year: toGurmukhiNum(nanakshahiDate.englishDate.year),
      day: nanakshahiDate.punjabiDate.day,
      dayShort: nanakshahiDate.punjabiDate.day.substring(0, 3)
    },
    leapYear: calendarData.getDaysInYear(nanakshahiDate.englishDate.year) === 366,
    sgpcCompliant: true // Our special addition
  }
}

/**
 * Get Gregorian date from Nanakshahi date (compatible with nanakshahi-js.getDateFromNanakshahi)
 * @param {number} nanakshahiDate - Nanakshahi date
 * @param {number} nanakshahiMonth - Nanakshahi month (1-12)
 * @param {number} nanakshahiYear - Nanakshahi year
 * @returns {Date} Gregorian date
 */
function getDateFromNanakshahi (nanakshahiDate, nanakshahiMonth, nanakshahiYear) {
  return dateConversion.getGregorianDate(nanakshahiYear, nanakshahiMonth, nanakshahiDate)
}

/**
 * Get Gurpurabs for a specific day (compatible with nanakshahi-js.getGurpurabsForDay)
 * @param {Date} gregorianDate - JavaScript Date object
 * @returns {Array} Array of Gurpurabs for the day
 */
function getGurpurabsForDay (gregorianDate = new Date()) {
  const fixedGurpurabs = gurpurabData.getGurpurabsForDay(gregorianDate)
  const movableGurpurabsForDate = movableGurpurabs.getMovableGurpurabsForDate(gregorianDate)

  // Combine fixed and movable Gurpurabs
  const allGurpurabs = [...fixedGurpurabs, ...movableGurpurabsForDate]

  // Format to match nanakshahi-js structure
  return allGurpurabs.map(gurpurab => ({
    en: gurpurab.en || gurpurab.name?.en || gurpurab.name,
    pa: gurpurab.pa || gurpurab.name?.pa || gurpurab.nameGurmukhi,
    type: gurpurab.type,
    movable: gurpurab.movable || false,
    sgpcCorrected: gurpurab.sgpcCorrected || false
  }))
}

/**
 * Get Gurpurabs for a specific month (compatible with nanakshahi-js.getGurpurabsForMonth)
 * @param {number} nanakshahiMonth - Nanakshahi month (1-12)
 * @param {number} nanakshahiYear - Nanakshahi year
 * @returns {Array} Array of Gurpurabs for the month
 */
function getGurpurabsForMonth (nanakshahiMonth, nanakshahiYear) {
  // Get all gurpurabs for the year and filter by month
  const allGurpurabs = gurpurabData.getAllGurpurabsForYear(nanakshahiYear)
  const monthGurpurabs = allGurpurabs.filter(gurpurab => gurpurab.nanakshahiDate.month === nanakshahiMonth)

  // Add movable Gurpurabs that fall in this month
  const gregorianYear = nanakshahiYear + 1468
  const movableGurpurabsForYear = movableGurpurabs.getMovableGurpurabsForYear(gregorianYear)

  const movableInMonth = movableGurpurabsForYear.filter(gurpurab => {
    const nanakshahiDate = dateConversion.getNanakshahiDate(gurpurab.gregorianDate)
    return nanakshahiDate && nanakshahiDate.englishDate.month === nanakshahiMonth
  })

  return [...monthGurpurabs, ...movableInMonth].map(gurpurab => ({
    date: gurpurab.nanakshahiDate?.day || gurpurab.date,
    gurpurabs: [{
      en: gurpurab.en || gurpurab.name?.en || gurpurab.name,
      pa: gurpurab.pa || gurpurab.name?.pa || gurpurab.nameGurmukhi,
      type: gurpurab.type,
      movable: gurpurab.movable || false,
      sgpcCorrected: gurpurab.sgpcCorrected || false
    }]
  }))
}

/**
 * Find movable Gurpurab (compatible with nanakshahi-js.findMovableGurpurab)
 * @param {string} gurpurab - Gurpurab name
 * @param {number} year - Gregorian year
 * @returns {Object} Gurpurab information
 */
function findMovableGurpurab (gurpurab, year = new Date().getFullYear()) {
  const movableGurpurab = movableGurpurabs.findMovableGurpurab(gurpurab, year)

  // Format to match nanakshahi-js structure
  return {
    gregorianDate: movableGurpurab.gregorianDate,
    name: {
      en: `${movableGurpurab.name.en} (${year})`,
      pa: `${movableGurpurab.name.pa} (${year})`,
      type: movableGurpurab.name.type,
      movable: true,
      sgpcSource: true // Our special addition
    }
  }
}

/**
 * Convert number to Gurmukhi numerals
 * @param {number} num - Number to convert
 * @returns {string} Gurmukhi numeral
 */
function toGurmukhiNum (num) {
  const gurmukhiNumerals = ['੦', '੧', '੨', '੩', '੪', '੫', '੬', '੭', '੮', '੯']
  return num.toString().split('').map(digit => gurmukhiNumerals[parseInt(digit)]).join('')
}

/**
 * Enhanced API functions (not in nanakshahi-js)
 */

/**
 * Get SGPC compliance status
 * @returns {Object} SGPC compliance information
 */
function getSGPCComplianceStatus () {
  const currentYear = new Date().getFullYear()
  const nanakshahiYear = currentYear - 1468

  return {
    sgpcCompliant: true,
    version: '2.0-sgpc',
    supportedYears: '2024-2035',
    currentYear: nanakshahiYear,
    corrections: {
      july5Fixed: true,
      jethLengthCorrected: true,
      movableGurpurabs: true
    },
    features: {
      accurateCalendar: true,
      movableGurpurabs: true,
      communityDriven: true,
      sgpcCompliant: true
    }
  }
}

/**
 * Get calendar data for a specific year
 * @param {number} nanakshahiYear - Nanakshahi year
 * @returns {Object} Calendar data
 */
function getCalendarData (nanakshahiYear) {
  const monthLengths = calendarData.getMonthLengths(nanakshahiYear)
  const allGurpurabs = gurpurabData.getAllGurpurabsForYear(nanakshahiYear)

  return {
    year: nanakshahiYear,
    monthLengths,
    totalDays: calendarData.getDaysInYear(nanakshahiYear),
    status: calendarData.checkCalendarDataStatus(nanakshahiYear),
    months: calendarData.NANAKSHAHI_MONTHS.en.map((month, index) => ({
      name: month,
      days: monthLengths[index],
      index: index + 1
    })),
    gurpurabs: allGurpurabs
  }
}

/**
 * Validate date against SGPC calendar
 * @param {Date} gregorianDate - Date to validate
 * @returns {Object} Validation results
 */
function validateDate (gregorianDate) {
  const nanakshahiDate = dateConversion.getNanakshahiDate(gregorianDate)

  return {
    valid: nanakshahiDate !== null,
    nanakshahiDate,
    sgpcCompliant: true,
    corrections: []
  }
}

/**
 * Get migration helper for nanakshahi-js users
 * @returns {Object} Migration information
 */
function getMigrationGuide () {
  return {
    from: 'nanakshahi-js',
    to: 'sgpc-nanakshahi',
    message: 'Successfully migrated to SGPC-compliant Nanakshahi calendar',
    changes: [
      'July 5th now correctly shows Miri Piri Divas',
      'Jeth 2025 correctly has 32 days',
      'All dates validated against SGPC calendar',
      'Enhanced API with SGPC compliance information'
    ],
    compatibility: 'Full API compatibility with nanakshahi-js maintained'
  }
}

module.exports = {
  // Compatible API functions
  getNanakshahiDate,
  getDateFromNanakshahi,
  getGurpurabsForDay,
  getGurpurabsForMonth,
  findMovableGurpurab,

  // Enhanced API functions
  getSGPCComplianceStatus,
  getCalendarData,
  validateDate,
  getMigrationGuide,

  // Utility functions
  toGurmukhiNum
}