<?php
/**
 * @package AKSRT
 */

namespace AKSRT\Credits;

defined('ABSPATH') || exit;

class Balance {

	public const META_KEY = 'aksrt_balance';

	/**
	 * Current cash balance (yuan).
	 */
	public static function balance(int $user_id): float {
		if ($user_id <= 0) {
			return 0.0;
		}
		$val = get_user_meta($user_id, self::META_KEY, true);
		return is_numeric($val) ? round((float) $val, 2) : 0.0;
	}

	public static function get_balance(int $user_id): float {
		return self::balance($user_id);
	}

	/**
	 * Credit cash wallet.
	 *
	 * @param array<string,mixed> $ref
	 * @return float|\WP_Error New balance.
	 */
	public static function add(int $user_id, float $delta, string $reason, array $ref = [], string $remark = '') {
		if ($user_id <= 0) {
			return new \WP_Error('aksrt_balance_user', __('用户无效', 'aksrt'));
		}
		$delta = round((float) $delta, 2);
		if ($delta <= 0) {
			return new \WP_Error('aksrt_balance_delta', __('增加余额必须为正数', 'aksrt'));
		}

		$new = self::atomic_update($user_id, $delta, false);
		if ($new === null) {
			return new \WP_Error('aksrt_balance_db', __('余额写入失败', 'aksrt'));
		}
		self::log($user_id, $delta, $new, $reason, $ref, $remark);
		do_action('aksrt_balance_added', $user_id, $delta, $reason, $new);
		return $new;
	}

	/**
	 * Debit cash wallet.
	 *
	 * @param array<string,mixed> $ref
	 * @return float|\WP_Error New balance.
	 */
	public static function deduct(int $user_id, float $cost, string $reason, array $ref = [], string $remark = '') {
		if ($user_id <= 0) {
			return new \WP_Error('aksrt_balance_user', __('用户无效', 'aksrt'));
		}
		$cost = round((float) $cost, 2);
		if ($cost < 0) {
			return new \WP_Error('aksrt_balance_delta', __('扣减余额必须为非负数', 'aksrt'));
		}
		if ($cost === 0.0) {
			return self::balance($user_id);
		}

		$new = self::atomic_update($user_id, $cost, true);
		if ($new === null) {
			$current = self::balance($user_id);
			return new \WP_Error('aksrt_balance_insufficient', __('余额不足', 'aksrt'), [
				'balance' => $current,
				'cost'    => $cost,
			]);
		}
		self::log($user_id, -$cost, $new, $reason, $ref, $remark);
		do_action('aksrt_balance_deducted', $user_id, $cost, $reason, $new);
		return $new;
	}

	/**
	 * @return float|null
	 */
	private static function atomic_update(int $user_id, float $abs_delta, bool $is_deduct) {
		global $wpdb;

		$abs_delta = round(abs($abs_delta), 2);
		$meta_key  = self::META_KEY;
		$table     = $wpdb->usermeta;

		// Ensure meta row exists.
		$exists = $wpdb->get_var($wpdb->prepare(
			"SELECT umeta_id FROM {$table} WHERE user_id = %d AND meta_key = %s LIMIT 1",
			$user_id,
			$meta_key
		));
		if (!$exists) {
			add_user_meta($user_id, $meta_key, '0', true);
		}

		if ($is_deduct) {
			// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
			$updated = $wpdb->query($wpdb->prepare(
				"UPDATE {$table}
				 SET meta_value = CAST(ROUND(CAST(meta_value AS DECIMAL(18,2)) - %f, 2) AS CHAR)
				 WHERE user_id = %d AND meta_key = %s
				   AND CAST(meta_value AS DECIMAL(18,2)) >= %f",
				$abs_delta,
				$user_id,
				$meta_key,
				$abs_delta
			));
		} else {
			// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
			$updated = $wpdb->query($wpdb->prepare(
				"UPDATE {$table}
				 SET meta_value = CAST(ROUND(CAST(meta_value AS DECIMAL(18,2)) + %f, 2) AS CHAR)
				 WHERE user_id = %d AND meta_key = %s",
				$abs_delta,
				$user_id,
				$meta_key
			));
		}

		if ($updated !== 1) {
			return null;
		}

		wp_cache_delete($user_id, 'user_meta');
		return self::balance($user_id);
	}

	/**
	 * @param array<string,mixed> $ref
	 */
	public static function log(int $user_id, float $delta, float $balance_after, string $reason, array $ref = [], string $remark = ''): void {
		global $wpdb;
		if (!class_exists('\AKSRT\Core\DBMigrator')) {
			return;
		}
		$table = \AKSRT\Core\DBMigrator::table('balance_log');
		if ($table === '') {
			return;
		}

		$ip = '';
		if (!empty($_SERVER['REMOTE_ADDR'])) {
			$ip = sanitize_text_field(wp_unslash((string) $_SERVER['REMOTE_ADDR']));
		}
		$ua = '';
		if (!empty($_SERVER['HTTP_USER_AGENT'])) {
			$ua = substr(sanitize_text_field(wp_unslash((string) $_SERVER['HTTP_USER_AGENT'])), 0, 255);
		}

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
		$wpdb->insert(
			$table,
			[
				'user_id'       => $user_id,
				'delta'         => round($delta, 2),
				'balance_after' => round($balance_after, 2),
				'reason'        => sanitize_key(substr($reason, 0, 64)),
				'remark'        => $remark !== '' ? sanitize_text_field(substr($remark, 0, 255)) : null,
				'ref_type'      => isset($ref['type']) ? sanitize_key((string) $ref['type']) : null,
				'ref_id'        => isset($ref['id']) ? (int) $ref['id'] : (isset($ref['ref_id']) ? (int) $ref['ref_id'] : null),
				'ip'            => $ip !== '' ? $ip : null,
				'ua'            => $ua !== '' ? $ua : null,
				'created_at'    => current_time('mysql', true),
			],
			['%d', '%f', '%f', '%s', '%s', '%s', '%d', '%s', '%s', '%s']
		);
	}

	/**
	 * @param array<string,mixed> $args
	 * @return array{items:array<int,array<string,mixed>>,total:int}
	 */
	public static function get_log(array $args = []): array {
		global $wpdb;
		if (!class_exists('\AKSRT\Core\DBMigrator')) {
			return ['items' => [], 'total' => 0];
		}
		$table = \AKSRT\Core\DBMigrator::table('balance_log');
		if ($table === '') {
			return ['items' => [], 'total' => 0];
		}

		$user_id  = max(0, (int) ($args['user_id'] ?? 0));
		$page     = max(1, (int) ($args['page'] ?? 1));
		$per_page = max(1, min(50, (int) ($args['per_page'] ?? 10)));
		$offset   = ($page - 1) * $per_page;

		$where  = '1=1';
		$params = [];
		if ($user_id > 0) {
			$where   .= ' AND user_id = %d';
			$params[] = $user_id;
		}

		// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$total_sql = "SELECT COUNT(*) FROM {$table} WHERE {$where}";
		// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
		$total = (int) ($params ? $wpdb->get_var($wpdb->prepare($total_sql, $params)) : $wpdb->get_var($total_sql));

		// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$list_sql = "SELECT * FROM {$table} WHERE {$where} ORDER BY id DESC LIMIT %d OFFSET %d";
		$list_params = array_merge($params, [$per_page, $offset]);
		// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
		$rows = $wpdb->get_results($wpdb->prepare($list_sql, $list_params), ARRAY_A);
		if (!is_array($rows)) {
			$rows = [];
		}

		$items = [];
		foreach ($rows as $row) {
			$items[] = [
				'id'            => (int) ($row['id'] ?? 0),
				'user_id'       => (int) ($row['user_id'] ?? 0),
				'delta'         => round((float) ($row['delta'] ?? 0), 2),
				'balance_after' => round((float) ($row['balance_after'] ?? 0), 2),
				'reason'        => (string) ($row['reason'] ?? ''),
				'remark'        => (string) ($row['remark'] ?? ''),
				'created_at'    => (string) ($row['created_at'] ?? ''),
			];
		}

		return ['items' => $items, 'total' => $total];
	}

	/**
	 * Whether cash wallet feature is enabled (Zibll pay_balance_s).
	 */
	public static function enabled(): bool {
		if (!class_exists('\AKSRT\Settings\Settings')) {
			return false;
		}
		if (method_exists('\AKSRT\Settings\Settings', 'get_payment_recharge_settings')) {
			$cfg = \AKSRT\Settings\Settings::get_payment_recharge_settings();
			return !empty($cfg['enabled']);
		}
		return !empty(\AKSRT\Settings\Settings::get_all()['pay_balance_s']);
	}

	/**
	 * Atomically transfer cash balance between two users.
	 *
	 * @param array<string,mixed> $ref
	 * @return array{sender_balance:float,recipient_balance:float}|\WP_Error
	 */
	public static function transfer(int $sender_id, int $recipient_id, float $amount, string $reason_out = 'tip_sent', string $reason_in = 'tip_received', array $ref = [], string $remark = '') {
		global $wpdb;

		$amount = round($amount, 2);
		if ($sender_id <= 0 || $recipient_id <= 0 || $sender_id === $recipient_id) {
			return new \WP_Error('aksrt_balance_transfer_user', __('转账用户无效', 'aksrt'));
		}
		if ($amount <= 0) {
			return new \WP_Error('aksrt_balance_transfer_amount', __('转账金额必须大于零', 'aksrt'));
		}
		if (!class_exists('\AKSRT\Core\DBMigrator')) {
			return new \WP_Error('aksrt_balance_transfer_unavailable', __('余额服务不可用', 'aksrt'));
		}

		foreach ([$sender_id, $recipient_id] as $user_id) {
			if (!metadata_exists('user', $user_id, self::META_KEY)) {
				add_user_meta($user_id, self::META_KEY, '0', true);
			}
		}

		$meta_table = $wpdb->usermeta;
		$log_table = \AKSRT\Core\DBMigrator::table('balance_log');
		$locked_ids = [$sender_id, $recipient_id];
		sort($locked_ids, SORT_NUMERIC);

		$wpdb->query('START TRANSACTION');
		try {
			foreach ($locked_ids as $user_id) {
				$wpdb->get_var($wpdb->prepare(
					"SELECT umeta_id FROM {$meta_table} WHERE user_id = %d AND meta_key = %s FOR UPDATE",
					$user_id,
					self::META_KEY
				));
			}

			$sender_before = (float) $wpdb->get_var($wpdb->prepare(
				"SELECT meta_value FROM {$meta_table} WHERE user_id = %d AND meta_key = %s LIMIT 1",
				$sender_id,
				self::META_KEY
			));
			if ($sender_before < $amount) {
				$wpdb->query('ROLLBACK');
				return new \WP_Error('aksrt_balance_insufficient', __('余额不足', 'aksrt'));
			}

			$sender_after = round($sender_before - $amount, 2);
			$recipient_before = (float) $wpdb->get_var($wpdb->prepare(
				"SELECT meta_value FROM {$meta_table} WHERE user_id = %d AND meta_key = %s LIMIT 1",
				$recipient_id,
				self::META_KEY
			));
			$recipient_after = round($recipient_before + $amount, 2);

			$sender_updated = $wpdb->update($meta_table, ['meta_value' => (string) $sender_after], ['user_id' => $sender_id, 'meta_key' => self::META_KEY], ['%s'], ['%d', '%s']);
			$recipient_updated = $wpdb->update($meta_table, ['meta_value' => (string) $recipient_after], ['user_id' => $recipient_id, 'meta_key' => self::META_KEY], ['%s'], ['%d', '%s']);
			if ($sender_updated !== 1 || $recipient_updated !== 1) {
				throw new \RuntimeException('balance_update_failed');
			}

			$ref_type = isset($ref['type']) ? sanitize_key((string) $ref['type']) : 'tip';
			$ref_id = isset($ref['id']) ? (int) $ref['id'] : null;
			$created_at = current_time('mysql', true);
			$log_rows = [
				[$sender_id, -$amount, $sender_after, $reason_out],
				[$recipient_id, $amount, $recipient_after, $reason_in],
			];
			foreach ($log_rows as [$user_id, $delta, $balance_after, $reason]) {
				$inserted = $wpdb->insert($log_table, [
					'user_id' => $user_id,
					'delta' => $delta,
					'balance_after' => $balance_after,
					'reason' => sanitize_key($reason),
					'remark' => $remark !== '' ? sanitize_text_field(substr($remark, 0, 255)) : null,
					'ref_type' => $ref_type,
					'ref_id' => $ref_id,
					'created_at' => $created_at,
				], ['%d', '%f', '%f', '%s', '%s', '%s', '%d', '%s']);
				if ($inserted !== 1) {
					throw new \RuntimeException('balance_log_failed');
				}
			}

			$wpdb->query('COMMIT');
			wp_cache_delete($sender_id, 'user_meta');
			wp_cache_delete($recipient_id, 'user_meta');
			do_action('aksrt_balance_transferred', $sender_id, $recipient_id, $amount, $ref);
			return ['sender_balance' => $sender_after, 'recipient_balance' => $recipient_after];
		} catch (\Throwable $e) {
			$wpdb->query('ROLLBACK');
			return new \WP_Error('aksrt_balance_transfer_failed', __('打赏入账失败，请稍后重试', 'aksrt'));
		}
	}

	/**
	 * Format yuan for display.
	 */
	public static function format(float $amount): string {
		return number_format_i18n(round($amount, 2), 2);
	}

	/**
	 * Reason label for ledger UI.
	 */
	public static function reason_label(string $reason): string {
		$map = [
			'card_pass_balance' => __('卡密充值', 'aksrt'),
			'order_payment'     => __('订单支付', 'aksrt'),
			'order_refund'      => __('订单退款', 'aksrt'),
			'recharge'          => __('余额充值', 'aksrt'),
			'transfer_in'       => __('转入', 'aksrt'),
			'transfer_out'      => __('转出', 'aksrt'),
			'tip_sent'          => __('打赏支出', 'aksrt'),
			'tip_received'      => __('收到打赏', 'aksrt'),
			'admin'             => __('管理员调整', 'aksrt'),
			'exchange_from_credits' => __('积分兑换', 'aksrt'),
			'withdraw_hold'     => __('提现冻结', 'aksrt'),
			'withdraw_refund'   => __('提现退回', 'aksrt'),
		];
		$key = sanitize_key($reason);
		return $map[$key] ?? ($reason !== '' ? $reason : __('余额变动', 'aksrt'));
	}
}