<?php
/**
 * Utility functions.
 *
 * @package WC_Email_Discount_Manager
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Static helper methods shared between admin and frontend.
 */
class WC_EDM_Helpers {

	/**
	 * Find the best matching email assignment for an email address.
	 *
	 * Match priority:
	 *  1. Exact email match (john@example.com)
	 *  2. Domain match (@company.com)
	 *  3. Partial match (john)
	 *
	 * @param string $email Email address.
	 * @return object|null Matching row from the emails table, or null.
	 */
	public static function find_email_match( $email ) {
		$email = strtolower( trim( (string) $email ) );

		if ( '' === $email || ! is_email( $email ) ) {
			return null;
		}

		$assignments = WC_EDM_DB::get_active_emails();

		if ( empty( $assignments ) ) {
			return null;
		}

		$domain_match  = null;
		$partial_match = null;

		foreach ( $assignments as $assignment ) {
			$pattern = strtolower( trim( $assignment->email_pattern ) );

			if ( '' === $pattern ) {
				continue;
			}

			// 1. Exact match wins immediately.
			if ( $pattern === $email ) {
				return $assignment;
			}

			// 2. Domain match: pattern starts with '@'.
			if ( null === $domain_match && 0 === strpos( $pattern, '@' ) ) {
				if ( substr( $email, -strlen( $pattern ) ) === $pattern ) {
					$domain_match = $assignment;
				}
				continue;
			}

			// 3. Partial match: pattern occurs anywhere in the email.
			if ( null === $partial_match && false === strpos( $pattern, '@' ) && false !== strpos( $email, $pattern ) ) {
				$partial_match = $assignment;
			}
		}

		if ( $domain_match ) {
			return $domain_match;
		}

		return $partial_match;
	}

	/**
	 * Get all product categories.
	 *
	 * @return WP_Term[]
	 */
	public static function get_product_categories() {
		$terms = get_terms(
			array(
				'taxonomy'   => 'product_cat',
				'hide_empty' => false,
				'orderby'    => 'name',
				'order'      => 'ASC',
			)
		);

		return is_wp_error( $terms ) ? array() : $terms;
	}

	/**
	 * Get every shipping method instance across all zones (including "Rest of the world").
	 *
	 * @return array Map of method key ("flat_rate:3") => array{ label, zone, method }.
	 */
	public static function get_all_shipping_methods() {
		$methods = array();

		if ( ! class_exists( 'WC_Shipping_Zones' ) ) {
			return $methods;
		}

		$zones = WC_Shipping_Zones::get_zones();

		// Zone 0 = "Locations not covered by your other zones".
		$rest_of_world = new WC_Shipping_Zone( 0 );
		$zones[]       = array(
			'zone_name'        => $rest_of_world->get_zone_name(),
			'shipping_methods' => $rest_of_world->get_shipping_methods(),
		);

		foreach ( $zones as $zone ) {
			$zone_name = $zone['zone_name'];

			foreach ( $zone['shipping_methods'] as $method ) {
				$key = $method->id . ':' . $method->get_instance_id();

				$methods[ $key ] = array(
					'key'    => $key,
					'label'  => $method->get_title(),
					'zone'   => $zone_name,
					'method' => $method->id,
				);
			}
		}

		return $methods;
	}

	/**
	 * Get all published WooCommerce coupon codes.
	 *
	 * @return string[]
	 */
	public static function get_coupon_codes() {
		$posts = get_posts(
			array(
				'post_type'      => 'shop_coupon',
				'post_status'    => 'publish',
				'posts_per_page' => 500,
				'orderby'        => 'title',
				'order'          => 'ASC',
			)
		);

		$codes = array();

		foreach ( $posts as $post ) {
			$codes[] = wc_format_coupon_code( $post->post_title );
		}

		return array_values( array_unique( $codes ) );
	}

	/**
	 * Get a human-readable description of an email assignment's target.
	 *
	 * @param object $assignment Row from the emails table.
	 * @return string
	 */
	public static function describe_assignment( $assignment ) {
		$extra = ! empty( $assignment->free_shipping )
			? ' + ' . __( 'free shipping', 'wc-email-discount' )
			: '';

		return self::describe_assignment_type( $assignment ) . $extra;
	}

	/**
	 * Describe the discount part of an assignment (without extras).
	 *
	 * @param object $assignment Row from the emails table.
	 * @return string
	 */
	private static function describe_assignment_type( $assignment ) {
		switch ( $assignment->assignment_type ) {
			case 'group':
				$group = $assignment->group_id ? WC_EDM_DB::get_group( (int) $assignment->group_id ) : null;
				if ( $group ) {
					/* translators: 1: group name, 2: discount percent */
					return sprintf( __( '%1$s (%2$s%%)', 'wc-email-discount' ), $group->name, wc_format_localized_decimal( $group->discount_percent ) );
				}
				return __( 'Group missing', 'wc-email-discount' );

			case 'coupon':
				/* translators: %s: coupon code */
				return sprintf( __( 'Coupon: %s', 'wc-email-discount' ), $assignment->coupon_code );

			case 'custom':
				/* translators: %s: discount percent */
				return sprintf( __( '%s%% off entire cart', 'wc-email-discount' ), wc_format_localized_decimal( $assignment->custom_discount ) );
		}

		return '';
	}

	/**
	 * Sanitize a discount percent value into the 0–100 range.
	 *
	 * @param mixed $value Raw value.
	 * @return float
	 */
	public static function sanitize_percent( $value ) {
		$value = (float) wc_format_decimal( wp_unslash( $value ) );
		return max( 0, min( 100, $value ) );
	}

	/**
	 * Build an admin URL for the plugin page.
	 *
	 * @param array $args Extra query args (tab, action, id, ...).
	 * @return string
	 */
	public static function admin_url( $args = array() ) {
		return add_query_arg(
			array_merge( array( 'page' => 'wc-email-discounts' ), $args ),
			admin_url( 'admin.php' )
		);
	}
}