<?php
/**
 * Phone number normalization utilities.
 *
 * @package SixRsh_WhatsApp
 */

defined( 'ABSPATH' ) || exit;

/**
 * Class SixRsh_Phone
 */
class SixRsh_Phone {

	/**
	 * Country dial codes (ISO-2 → numeric prefix, no leading +).
	 *
	 * @var array<string,string>
	 */
	const DIAL_CODES = array(
		// Middle East & North Africa
		'AE' => '971', 'SA' => '966', 'EG' => '20',  'KW' => '965', 'QA' => '974',
		'BH' => '973', 'OM' => '968', 'JO' => '962', 'IQ' => '964', 'LB' => '961',
		'YE' => '967', 'SY' => '963', 'PS' => '970', 'IL' => '972', 'IR' => '98',
		'MA' => '212', 'DZ' => '213', 'TN' => '216', 'LY' => '218', 'SD' => '249',
		'MR' => '222',
		// Europe
		'GB' => '44',  'DE' => '49',  'FR' => '33',  'IT' => '39',  'ES' => '34',
		'NL' => '31',  'BE' => '32',  'CH' => '41',  'AT' => '43',  'SE' => '46',
		'NO' => '47',  'DK' => '45',  'FI' => '358', 'PT' => '351', 'IE' => '353',
		'PL' => '48',  'CZ' => '420', 'SK' => '421', 'HU' => '36',  'RO' => '40',
		'BG' => '359', 'GR' => '30',  'HR' => '385', 'RS' => '381', 'SI' => '386',
		'UA' => '380', 'RU' => '7',   'BY' => '375', 'LT' => '370', 'LV' => '371',
		'EE' => '372', 'CY' => '357', 'MT' => '356', 'LU' => '352', 'IS' => '354',
		'AL' => '355', 'MK' => '389', 'BA' => '387', 'MD' => '373', 'GE' => '995',
		'AM' => '374', 'AZ' => '994',
		// Americas
		'US' => '1',   'CA' => '1',   'MX' => '52',  'BR' => '55',  'AR' => '54',
		'CO' => '57',  'CL' => '56',  'PE' => '51',  'VE' => '58',  'EC' => '593',
		'UY' => '598', 'PY' => '595', 'BO' => '591', 'CR' => '506', 'PA' => '507',
		'DO' => '1',   'GT' => '502', 'SV' => '503', 'HN' => '504', 'NI' => '505',
		'JM' => '1',   'TT' => '1',
		// Asia-Pacific
		'IN' => '91',  'PK' => '92',  'BD' => '880', 'LK' => '94',  'NP' => '977',
		'AF' => '93',  'CN' => '86',  'HK' => '852', 'MO' => '853', 'TW' => '886',
		'JP' => '81',  'KR' => '82',  'SG' => '65',  'MY' => '60',  'TH' => '66',
		'ID' => '62',  'PH' => '63',  'VN' => '84',  'MM' => '95',  'KH' => '855',
		'LA' => '856', 'AU' => '61',  'NZ' => '64',  'KZ' => '7',   'UZ' => '998',
		'TM' => '993', 'KG' => '996', 'TJ' => '992', 'MN' => '976', 'BN' => '673',
		'MV' => '960', 'TR' => '90',
		// Sub-Saharan Africa
		'NG' => '234', 'ZA' => '27',  'KE' => '254', 'GH' => '233', 'ET' => '251',
		'TZ' => '255', 'UG' => '256', 'RW' => '250', 'ZM' => '260', 'ZW' => '263',
		'MZ' => '258', 'AO' => '244', 'CM' => '237', 'CI' => '225', 'SN' => '221',
		'ML' => '223', 'BF' => '226', 'NE' => '227', 'TD' => '235', 'SO' => '252',
		'DJ' => '253', 'ER' => '291', 'GM' => '220', 'GN' => '224', 'LR' => '231',
		'SL' => '232', 'TG' => '228', 'BJ' => '229', 'GA' => '241', 'CG' => '242',
		'CD' => '243', 'MG' => '261', 'MU' => '230', 'NA' => '264', 'BW' => '267',
		'MW' => '265', 'LS' => '266', 'SZ' => '268',
	);

	/**
	 * Normalize a raw phone string to E.164 format (with leading +).
	 *
	 * Returns null when the number is invalid.
	 *
	 * @param string $phone        Raw phone number from any source.
	 * @param string $country_code ISO-2 country code (default: AE).
	 *
	 * @return string|null E.164 string or null.
	 */
	/**
	 * Country to assume for a phone typed without a country code.
	 *
	 * 6rsh serves stores worldwide, so never default to one country: the
	 * customer's own billing country wins, then the country saved at setup,
	 * then the store's WooCommerce base country. Empty = don't guess (only
	 * numbers already in international format are accepted).
	 *
	 * @param string $billing_country The customer's billing country, if known.
	 *
	 * @return string ISO-3166 alpha-2 or ''.
	 */
	public static function country_for( string $billing_country = '' ): string {
		$billing_country = strtoupper( trim( $billing_country ) );
		if ( '' !== $billing_country && isset( self::DIAL_CODES[ $billing_country ] ) ) {
			return $billing_country;
		}
		$saved = strtoupper( (string) get_option( 'sixrsh_country_code', '' ) );
		if ( '' !== $saved ) {
			return $saved;
		}
		if ( function_exists( 'WC' ) && WC() && WC()->countries ) {
			return strtoupper( (string) WC()->countries->get_base_country() );
		}
		return '';
	}

	public static function normalize( string $phone, string $country_code = '' ): ?string {
		try {
			// Strip spaces, dashes, parentheses, dots but keep leading + and digits.
			$clean = preg_replace( '/[^\d+]/', '', $phone );

			if ( ! $clean ) {
				return null;
			}

			// Unknown store country → never guess a dial code; only numbers already
			// in an unambiguous international format are accepted below.
			$dial = self::DIAL_CODES[ strtoupper( $country_code ) ] ?? null;

			// Already in +E.164 format.
			if ( str_starts_with( $clean, '+' ) ) {
				$digits = substr( $clean, 1 );
				if ( ! self::valid_length( $digits ) ) {
					return null;
				}
				return '+' . $digits;
			}

			// 00-prefixed international format.
			if ( str_starts_with( $clean, '00' ) ) {
				$digits = substr( $clean, 2 );
				if ( ! self::valid_length( $digits ) ) {
					return null;
				}
				return '+' . $digits;
			}

			// From here on a local→international conversion needs a known dial code.
			if ( null === $dial ) {
				// Best effort: a long bare number may already embed its country code.
				if ( ! str_starts_with( $clean, '0' ) && strlen( $clean ) >= 10 && self::valid_length( $clean ) ) {
					return '+' . $clean;
				}
				return null;
			}

			// Local format with leading 0.
			if ( str_starts_with( $clean, '0' ) ) {
				$local  = substr( $clean, 1 );
				$digits = $dial . $local;
				if ( ! self::valid_length( $digits ) ) {
					return null;
				}
				return '+' . $digits;
			}

			// Bare number: prepend country dial code if it looks too short.
			if ( strlen( $clean ) < 10 ) {
				$digits = $dial . $clean;
				if ( ! self::valid_length( $digits ) ) {
					return null;
				}
				return '+' . $digits;
			}

			// Long enough to already have country code embedded or be a local long form.
			if ( self::valid_length( $clean ) ) {
				return '+' . $clean;
			}

			// Try prepending dial code.
			$digits = $dial . $clean;
			if ( self::valid_length( $digits ) ) {
				return '+' . $digits;
			}

			return null;

		} catch ( \Throwable $e ) {
			error_log( '[6rsh WhatsApp] Phone::normalize exception: ' . $e->getMessage() );
			return null;
		}
	}

	/**
	 * Strip all non-digit characters for use in wa.me URLs.
	 *
	 * @param string $phone E.164 or any phone string.
	 *
	 * @return string Digits only, no +.
	 */
	public static function to_wa_me( string $phone ): string {
		return preg_replace( '/\D/', '', $phone );
	}

	/**
	 * Validate that the digit string has a plausible E.164 length (7-15 digits).
	 *
	 * @param string $digits Pure digit string (no +).
	 *
	 * @return bool
	 */
	private static function valid_length( string $digits ): bool {
		$len = strlen( $digits );
		return $len >= 7 && $len <= 15;
	}
}