<?php
/**
 * Qixit Payment Class
 * Handles payment tracking and verification
 * 
 * @package Qixit
 * @version 2.0.0
 */

// Exit if accessed directly
if (!defined('ABSPATH')) {
    exit;
}

class Qixit_Payment {
    // phpcs:disable WordPress.DB.PreparedSQL.InterpolatedNotPrepared
    
    /**
     * Singleton instance
     */
    private static $instance = null;
    
    /**
     * Logger instance
     */
    private $logger;
    
    /**
     * Get singleton instance
     */
    public static function get_instance() {
        if (self::$instance === null) {
            self::$instance = new self();
        }
        return self::$instance;
    }
    
    /**
     * Constructor
     */
    private function __construct() {
        $this->logger = Qixit_Logger::get_instance();
    }

    /**
     * Ensure payment details table exists before reading/writing.
     */
    private function ensure_payment_table_exists() {
        global $wpdb;
        $table_name = esc_sql($wpdb->prefix . QIXIT_PAYMENT_DETAILS);
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- schema check against plugin-owned table.
        $exists = $wpdb->get_var("SHOW TABLES LIKE '{$table_name}'");
        if ($exists) {
            return true;
        }

        $charset_collate = $wpdb->get_charset_collate();
        $sql = "CREATE TABLE IF NOT EXISTS {$table_name} (
            payment_id BIGINT NOT NULL AUTO_INCREMENT,
            product_id BIGINT NULL,
            type VARCHAR(1) NOT NULL DEFAULT 'P',
            qixit_PID VARCHAR(255) DEFAULT NULL,
            qixit_PID_guid CHAR(36) DEFAULT NULL,
            qixit_id VARCHAR(60) DEFAULT NULL,
            qixit_user_id VARCHAR(100) DEFAULT NULL,
            txn_id VARCHAR(100) DEFAULT NULL,
            total DECIMAL(15,4) NOT NULL DEFAULT 0,
            payment_for VARCHAR(50) NOT NULL DEFAULT 'view_post',
            wp_user_id BIGINT DEFAULT NULL,
            percent_to_author DECIMAL(15,2) DEFAULT NULL,
            date_purchased DATETIME NULL DEFAULT NULL,
            PRIMARY KEY (payment_id),
            KEY idx_guid (qixit_PID_guid),
            KEY idx_user (wp_user_id),
            KEY idx_qixit_user (qixit_user_id),
            KEY idx_txn (txn_id)
        ) {$charset_collate}";
        // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared,WordPress.DB.DirectDatabaseQuery.SchemaChange,WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- CREATE TABLE uses trusted plugin constants only.
        $wpdb->query($sql);
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- schema check against plugin-owned table.
        $exists_after = $wpdb->get_var("SHOW TABLES LIKE '{$table_name}'");
        if (!$exists_after) {
            $this->logger->log('Failed to ensure payment details table exists: ' . $wpdb->last_error, 'error');
            return false;
        }
        return true;
    }
    
    /**
     * Record a payment
     * 
     * @param array $data Payment data
     * @return int|false Payment ID or false on failure
     */
    public function record_payment($data) {
        global $wpdb;
        
        if (!$this->ensure_payment_table_exists()) {
            return false;
        }

        $table_name = esc_sql($wpdb->prefix . QIXIT_PAYMENT_DETAILS);
        
        $defaults = array(
            'product_id' => 0,
            'type' => 'P', // P = Purchase, A = Advertisement
            'qixit_PID' => '',
            'qixit_PID_guid' => null,
            'qixit_id' => '',
            'qixit_user_id' => '', // Qixit username (e.g., "dave70")
            'txn_id' => '', // Transaction ID from Products Portal
            'total' => 0.00,
            'payment_for' => 'view_post',
            'wp_user_id' => get_current_user_id(),
            'percent_to_author' => 0,
            'date_purchased' => current_time('mysql')
        );
        
        $data = wp_parse_args($data, $defaults);
        
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery -- direct write to plugin-owned payments table.
        $result = $wpdb->insert($table_name, $data);
        
        if ($result) {
            $this->logger->log('Payment recorded: ID ' . $wpdb->insert_id);
            return $wpdb->insert_id;
        }
        
        $this->logger->log('Failed to record payment: ' . $wpdb->last_error, 'error');
        return false;
    }

    /**
     * Find an existing payment row by Products Portal transaction ID.
     *
     * @param string $txn_id Transaction GUID.
     * @return object|null
     */
    public function get_payment_by_txn_id($txn_id) {
        global $wpdb;

        $txn_id = sanitize_text_field((string) $txn_id);
        if ($txn_id === '') {
            return null;
        }

        if (!$this->ensure_payment_table_exists()) {
            return null;
        }

        $table_name = esc_sql($wpdb->prefix . QIXIT_PAYMENT_DETAILS);
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared
        return $wpdb->get_row(
            $wpdb->prepare("SELECT * FROM {$table_name} WHERE txn_id = %s LIMIT 1", $txn_id)
        );
    }
    
    /**
     * Get payment by ID
     * 
     * @param int $payment_id Payment ID
     * @return object|null Payment object or null
     */
    public function get_payment($payment_id) {
        global $wpdb;
        
        $table_name = esc_sql($wpdb->prefix . QIXIT_PAYMENT_DETAILS);
        
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- trusted plugin table name from $wpdb->prefix.
        return $wpdb->get_row(
            $wpdb->prepare("SELECT * FROM {$table_name} WHERE payment_id = %d", $payment_id)
        );
    }
    
    /**
     * Get payments for a product
     * 
     * @param int $product_id Product ID
     * @return array Payments
     */
    public function get_payments_by_product($product_id) {
        global $wpdb;
        
        $table_name = esc_sql($wpdb->prefix . QIXIT_PAYMENT_DETAILS);
        
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- trusted plugin table name from $wpdb->prefix.
        return $wpdb->get_results(
            $wpdb->prepare("SELECT * FROM {$table_name} WHERE product_id = %d ORDER BY date_purchased DESC", $product_id)
        );
    }
    
    /**
     * Get payments for a user
     * 
     * @param int $user_id WordPress user ID
     * @return array Payments
     */
    public function get_payments_by_user($user_id) {
        global $wpdb;
        
        $table_name = esc_sql($wpdb->prefix . QIXIT_PAYMENT_DETAILS);
        
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- trusted plugin table name from $wpdb->prefix.
        return $wpdb->get_results(
            $wpdb->prepare("SELECT * FROM {$table_name} WHERE wp_user_id = %d ORDER BY date_purchased DESC", $user_id)
        );
    }
    
    /**
     * Check if user has paid for content
     * 
     * @param int $product_id Product ID
     * @param int $user_id WordPress user ID (optional, defaults to current user)
     * @return bool True if paid
     */
    public function has_user_paid($product_id, $user_id = null) {
        global $wpdb;
        
        if ($user_id === null) {
            $user_id = get_current_user_id();
        }
        
        if (!$user_id) {
            return false;
        }
        
        $table_name = esc_sql($wpdb->prefix . QIXIT_PAYMENT_DETAILS);
        
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- trusted plugin table name from $wpdb->prefix.
        $count = $wpdb->get_var(
            $wpdb->prepare(
                "SELECT COUNT(*) FROM {$table_name} WHERE product_id = %d AND wp_user_id = %d",
                $product_id,
                $user_id
            )
        );
        
        return $count > 0;
    }
    
    /**
     * Get total revenue for a product
     * 
     * @param int $product_id Product ID
     * @return float Total revenue
     */
    public function get_product_revenue($product_id) {
        global $wpdb;
        
        $table_name = esc_sql($wpdb->prefix . QIXIT_PAYMENT_DETAILS);
        
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- trusted plugin table name from $wpdb->prefix.
        $total = $wpdb->get_var(
            $wpdb->prepare("SELECT SUM(total) FROM {$table_name} WHERE product_id = %d", $product_id)
        );
        
        return floatval($total);
    }
    
    /**
     * Get payment statistics
     * 
     * @return array Statistics
     */
    public function get_statistics() {
        global $wpdb;
        
        $table_name = esc_sql($wpdb->prefix . QIXIT_PAYMENT_DETAILS);
        
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- trusted plugin table name from $wpdb->prefix.
        $total_payments = $wpdb->get_var("SELECT COUNT(*) FROM {$table_name}");
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- trusted plugin table name from $wpdb->prefix.
        $total_revenue = $wpdb->get_var("SELECT SUM(total) FROM {$table_name}");
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- trusted plugin table name from $wpdb->prefix.
        $unique_buyers = $wpdb->get_var("SELECT COUNT(DISTINCT wp_user_id) FROM {$table_name}");
        
        return array(
            'total_payments' => intval($total_payments),
            'total_revenue' => floatval($total_revenue),
            'unique_buyers' => intval($unique_buyers)
        );
    }
    // phpcs:enable WordPress.DB.PreparedSQL.InterpolatedNotPrepared
}

// Initialize singleton
Qixit_Payment::get_instance();