<?php
/**
 * Storage for codes and their redemptions.
 *
 * A code row is either a personal code (with the recipient's e-mail) or a campaign's shared code
 * (empty e-mail). `uses` counts the orders currently holding the code; the redemptions table keeps
 * the history, including released uses.
 *
 * @package CNWS\Coupons
 */

namespace CNWS\Coupons;

defined( 'ABSPATH' ) || exit;

// phpcs:disable WordPress.DB.DirectDatabaseQuery -- Plugin-owned tables, named through the %i placeholder.

final class CodeRepository {

	/**
	 * Lookups by code within a request. WooCommerce builds coupon objects many times per page.
	 *
	 * @var array<string, object|null>
	 */
	private array $cache = array();

	/**
	 * @param string $code Code in any case.
	 * @return object|null Row with id, campaign_id, code, email, source, uses, expires_at, created_at.
	 */
	public function find_by_code( string $code ): ?object {
		global $wpdb;

		$code = self::normalize( $code );

		if ( '' === $code ) {
			return null;
		}

		if ( ! array_key_exists( $code, $this->cache ) ) {
			$row = $wpdb->get_row( $wpdb->prepare( 'SELECT * FROM %i WHERE code = %s', Tables::codes(), $code ) );

			$this->cache[ $code ] = $row ? $row : null;
		}

		return $this->cache[ $code ];
	}

	/**
	 * @param int    $campaign_id Campaign ID.
	 * @param string $email       Recipient.
	 */
	public function find_for( int $campaign_id, string $email ): ?object {
		global $wpdb;

		$row = $wpdb->get_row( $wpdb->prepare( 'SELECT * FROM %i WHERE campaign_id = %d AND email = %s', Tables::codes(), $campaign_id, self::normalize_email( $email ) ) );

		return $row ? $row : null;
	}

	/**
	 * @param string $code Code in any case.
	 */
	public function code_exists( string $code ): bool {
		global $wpdb;

		return (bool) $wpdb->get_var( $wpdb->prepare( 'SELECT id FROM %i WHERE code = %s', Tables::codes(), self::normalize( $code ) ) );
	}

	/**
	 * @param int $campaign_id Campaign ID.
	 * @return int Personal codes issued in the campaign.
	 */
	public function count_personal( int $campaign_id ): int {
		global $wpdb;

		return (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM %i WHERE campaign_id = %d AND email <> ''", Tables::codes(), $campaign_id ) );
	}

	/**
	 * @param int         $campaign_id Campaign ID.
	 * @param string      $code        Code.
	 * @param string      $email       Recipient, or '' for a shared code.
	 * @param string      $source      Who asked for the code.
	 * @param string|null $expires_at  Expiry in UTC, or null for none.
	 * @return bool False when the code or the campaign/email pair already exists.
	 */
	public function insert( int $campaign_id, string $code, string $email, string $source, ?string $expires_at ): bool {
		global $wpdb;

		unset( $this->cache[ self::normalize( $code ) ] );

		$data = array(
			'campaign_id' => $campaign_id,
			'code'        => self::normalize( $code ),
			'email'       => '' === $email ? '' : self::normalize_email( $email ),
			'source'      => substr( sanitize_key( $source ), 0, 60 ),
			'uses'        => 0,
			'expires_at'  => $expires_at,
			'created_at'  => current_time( 'mysql', true ),
		);

		$suppress = $wpdb->suppress_errors( true );
		$inserted = $wpdb->insert( Tables::codes(), $data );
		$wpdb->suppress_errors( $suppress );

		if ( $inserted ) {
			Dashboard::changed();
		}

		return (bool) $inserted;
	}

	/**
	 * Count one more use of a code, but only while it is below its limit. The limit is part of the
	 * UPDATE, so two orders placed at the same moment cannot both take the last use.
	 *
	 * @param int $code_id Code ID.
	 * @param int $limit   Most uses, or 0 for no limit.
	 * @return bool True when this call got a use.
	 */
	public function take( int $code_id, int $limit ): bool {
		global $wpdb;

		$updated = $limit > 0
			? $wpdb->query( $wpdb->prepare( 'UPDATE %i SET uses = uses + 1 WHERE id = %d AND uses < %d', Tables::codes(), $code_id, $limit ) )
			: $wpdb->query( $wpdb->prepare( 'UPDATE %i SET uses = uses + 1 WHERE id = %d', Tables::codes(), $code_id ) );

		$this->cache = array();
		Dashboard::changed();

		return 1 === $updated;
	}

	/**
	 * @param int $code_id Code ID.
	 */
	public function give_back( int $code_id ): void {
		global $wpdb;

		$wpdb->query( $wpdb->prepare( 'UPDATE %i SET uses = uses - 1 WHERE id = %d AND uses > 0', Tables::codes(), $code_id ) );

		$this->cache = array();
		Dashboard::changed();
	}

	/**
	 * The order's current (not released) use of a code.
	 *
	 * @param int $code_id  Code ID.
	 * @param int $order_id Order ID.
	 */
	public function active_redemption( int $code_id, int $order_id ): ?object {
		global $wpdb;

		$row = $wpdb->get_row( $wpdb->prepare( 'SELECT * FROM %i WHERE code_id = %d AND order_id = %d AND released_at IS NULL', Tables::redemptions(), $code_id, $order_id ) );

		return $row ? $row : null;
	}

	/**
	 * Current uses of a code by one e-mail address, other than by the given order.
	 *
	 * @param int    $code_id        Code ID.
	 * @param string $email          Customer e-mail.
	 * @param int    $except_order   Order to leave out, or 0.
	 */
	public function count_email_uses( int $code_id, string $email, int $except_order = 0 ): int {
		global $wpdb;

		return (int) $wpdb->get_var(
			$wpdb->prepare(
				'SELECT COUNT(*) FROM %i WHERE code_id = %d AND email = %s AND order_id <> %d AND released_at IS NULL',
				Tables::redemptions(),
				$code_id,
				self::normalize_email( $email ),
				$except_order
			)
		);
	}

	/**
	 * @param array $data code_id, campaign_id, order_id, email, country, discount_amount, order_total.
	 */
	public function record_redemption( array $data ): void {
		global $wpdb;

		$data['email']       = self::normalize_email( (string) ( $data['email'] ?? '' ) );
		$data['country']     = substr( strtoupper( (string) ( $data['country'] ?? '' ) ), 0, 2 );
		$data['redeemed_at'] = current_time( 'mysql', true );

		$wpdb->insert( Tables::redemptions(), $data );
		Dashboard::changed();
	}

	/**
	 * @param int $redemption_id Redemption ID.
	 */
	public function close_redemption( int $redemption_id ): void {
		global $wpdb;

		$wpdb->query( $wpdb->prepare( 'UPDATE %i SET released_at = %s WHERE id = %d AND released_at IS NULL', Tables::redemptions(), current_time( 'mysql', true ), $redemption_id ) );
		Dashboard::changed();
	}

	/**
	 * Recalculate the expiry of every code in a campaign after its end date or valid days changed.
	 *
	 * @param Campaign $campaign The changed campaign.
	 */
	public function refresh_expiry( Campaign $campaign ): void {
		global $wpdb;

		$rows = (array) $wpdb->get_results( $wpdb->prepare( 'SELECT id, created_at FROM %i WHERE campaign_id = %d', Tables::codes(), $campaign->id ) );

		foreach ( $rows as $row ) {
			$wpdb->update(
				Tables::codes(),
				array( 'expires_at' => Issuer::expires_at( $campaign, (int) strtotime( $row->created_at . ' UTC' ) ) ),
				array( 'id' => (int) $row->id )
			);
		}

		$this->cache = array();
	}

	/**
	 * @param int $campaign_id Campaign ID.
	 * @param int $limit       Maximum number of codes.
	 * @return object[] Codes of a campaign, newest first.
	 */
	public function for_campaign( int $campaign_id, int $limit = 500 ): array {
		global $wpdb;

		return (array) $wpdb->get_results( $wpdb->prepare( 'SELECT * FROM %i WHERE campaign_id = %d ORDER BY id DESC LIMIT %d', Tables::codes(), $campaign_id, $limit ) );
	}

	/**
	 * Personal codes and uses stored for one e-mail address, for the personal data exporter.
	 *
	 * @param string $email E-mail address.
	 * @return array{codes: object[], redemptions: object[]}
	 */
	public function for_email( string $email ): array {
		global $wpdb;

		$email = self::normalize_email( $email );

		if ( '' === $email ) {
			return array(
				'codes'       => array(),
				'redemptions' => array(),
			);
		}

		return array(
			'codes'       => (array) $wpdb->get_results( $wpdb->prepare( 'SELECT c.*, p.name AS campaign FROM %i c LEFT JOIN %i p ON p.id = c.campaign_id WHERE c.email = %s ORDER BY c.id', Tables::codes(), Tables::campaigns(), $email ) ),
			'redemptions' => (array) $wpdb->get_results( $wpdb->prepare( 'SELECT r.*, p.name AS campaign FROM %i r LEFT JOIN %i p ON p.id = r.campaign_id WHERE r.email = %s ORDER BY r.id', Tables::redemptions(), Tables::campaigns(), $email ) ),
		);
	}

	/**
	 * Remove an e-mail address for the personal data eraser. Codes keep working for the shop's
	 * figures but are no longer tied to the person: the address becomes a placeholder that is unique
	 * per code (a campaign may hold one code per address) and can never match a real customer.
	 *
	 * @param string $email E-mail address.
	 * @return int Rows changed.
	 */
	public function erase_email( string $email ): int {
		global $wpdb;

		$email = self::normalize_email( $email );

		if ( '' === $email ) {
			return 0;
		}

		$codes = (int) $wpdb->query( $wpdb->prepare( "UPDATE %i SET email = CONCAT( 'erased-', id, '@invalid' ) WHERE email = %s", Tables::codes(), $email ) );
		$uses  = (int) $wpdb->query( $wpdb->prepare( "UPDATE %i SET email = '' WHERE email = %s", Tables::redemptions(), $email ) );

		$this->cache = array();

		return $codes + $uses;
	}

	/**
	 * Codes are stored upper case. WooCommerce lower-cases codes, so every lookup goes through here.
	 *
	 * @param string $code Code in any case.
	 */
	public static function normalize( string $code ): string {
		return strtoupper( trim( $code ) );
	}

	/**
	 * @param string $email E-mail address.
	 */
	public static function normalize_email( string $email ): string {
		return strtolower( trim( sanitize_email( $email ) ) );
	}
}