<?php
/**
 * Migration Loader for Easy Invoice
 *
 * @package     EasyInvoice
 * @subpackage  Migration
 * @since       2.0.0
 */

namespace EasyInvoice\Migration;

use EasyInvoice\Migration\Src\SettingsMigration;
use EasyInvoice\Migration\Src\ClientMigration;
use EasyInvoice\Migration\Src\PostTypeMigration;
use EasyInvoice\Migration\Src\MetaMigration;
use EasyInvoice\Migration\Src\ProOptionsMigration;
use EasyInvoice\Migration\Src\DataCleanupMigration;

/**
 * Migration loader class.
 *
 * Handles migration-related initialization, asset loading, and AJAX handlers.
 *
 * @since 2.0.0
 */
class MigrationLoader {

    /**
     * Migration runner instance.
     *
     * @since 2.0.0
     * @var MigrationRunner
     */
    private static $migration_runner;

    /**
     * Initialize the migration loader.
     *
     * @since 2.0.0
     * @return void
     */
    public static function init() {
        // Initialize migration runner with version checker
        self::$migration_runner = new MigrationRunner(VersionChecker::get_instance());

        // Add AJAX handlers
        add_action('wp_ajax_easy_invoice_migration', [__CLASS__, 'handle_ajax_migration']);
        add_action('wp_ajax_easy_invoice_migration_status', [__CLASS__, 'handle_check_status']);
        add_action('wp_ajax_easy_invoice_migration_counts', [__CLASS__, 'handle_get_migration_counts']);
        add_action('wp_ajax_easy_invoice_migration_cleanup', [__CLASS__, 'handle_ajax_cleanup']);
    }

    /**
     * Handle AJAX migration request.
     *
     * @since 2.0.0
     * @return void
     */
    public static function handle_ajax_migration() {
        // Check nonce
        if (!wp_verify_nonce($_POST['nonce'], 'easy_invoice_migration_nonce')) {
            wp_die('Security check failed');
        }

        // Check permissions
        if (!current_user_can('manage_options')) {
            wp_die('Insufficient permissions');
        }

        try {
            $step = isset($_POST['step']) ? sanitize_text_field($_POST['step']) : '';

            if (empty($step)) {
                // Run full migration
                $result = self::$migration_runner->run_migration();
            } else {
                // Run specific step
                $result = self::$migration_runner->run_migration_step($step);
            }

            if ($result['success']) {
                wp_send_json_success($result);
            } else {
                wp_send_json_error($result);
            }

        } catch (\Exception $e) {
            wp_send_json_error([
                'message' => $e->getMessage(),
            ]);
        }
    }

    /**
     * Handle AJAX check status request.
     *
     * @since 2.0.0
     * @return void
     */
    public static function handle_check_status() {
        // Check nonce
        if (!wp_verify_nonce($_GET['nonce'], 'easy_invoice_migration_nonce')) {
            wp_die('Security check failed');
        }

        // Check permissions
        if (!current_user_can('manage_options')) {
            wp_die('Insufficient permissions');
        }

        try {
            $status = self::$migration_runner->get_migration_status();
            wp_send_json_success($status);

        } catch (\Exception $e) {
            wp_send_json_error([
                'message' => $e->getMessage(),
            ]);
        }
    }

    /**
     * Handle AJAX get migration counts request.
     *
     * @since 2.0.0
     * @return void
     */
    public static function handle_get_migration_counts() {
        // Check nonce
        if (!wp_verify_nonce($_GET['nonce'], 'easy_invoice_migration_nonce')) {
            wp_die('Security check failed');
        }

        // Check permissions
        if (!current_user_can('manage_options')) {
            wp_die('Insufficient permissions');
        }

        try {
            global $wpdb;

            // First, temporarily register old post types to ensure they're recognized
            self::register_old_post_types();

            // Count old post types using direct SQL queries with all possible statuses
            $invoice_count = (int)$wpdb->get_var($wpdb->prepare(
                "SELECT COUNT(*) FROM {$wpdb->posts}
                WHERE post_type = %s
                ",
                'easy-invoice'
            ));

            $quote_count = (int)$wpdb->get_var($wpdb->prepare(
                "SELECT COUNT(*) FROM {$wpdb->posts}
                WHERE post_type = %s
                ",
                'easy-invoice-quotes'
            ));

            $payment_count = (int)$wpdb->get_var($wpdb->prepare(
                "SELECT COUNT(*) FROM {$wpdb->posts}
                WHERE post_type = %s
                ",
                'easy-invoice-payment'
            ));

            // Double-check with meta data
            $invoice_meta_count = (int)$wpdb->get_var($wpdb->prepare(
                "SELECT COUNT(DISTINCT post_id) FROM {$wpdb->postmeta} pm
                JOIN {$wpdb->posts} p ON p.ID = pm.post_id
                WHERE p.post_type = %s
                ",
                'easy-invoice'
            ));

            $quote_meta_count = (int)$wpdb->get_var($wpdb->prepare(
                "SELECT COUNT(DISTINCT post_id) FROM {$wpdb->postmeta} pm
                JOIN {$wpdb->posts} p ON p.ID = pm.post_id
                WHERE p.post_type = %s
                ",
                'easy-invoice-quotes'
            ));

            $payment_meta_count = (int)$wpdb->get_var($wpdb->prepare(
                "SELECT COUNT(DISTINCT post_id) FROM {$wpdb->postmeta} pm
                JOIN {$wpdb->posts} p ON p.ID = pm.post_id
                WHERE p.post_type = %s
                ",
                'easy-invoice-payment'
            ));

            // Use the higher count between posts and meta
            $invoice_count = max($invoice_count, $invoice_meta_count);
            $quote_count = max($quote_count, $quote_meta_count);
            $payment_count = max($payment_count, $payment_meta_count);

            // Count old options
            $options_count = 0;
            $old_options = [
                'easy_invoice_version', 'easy_invoice_currency', 'easy_invoice_tax_rate',
                'easy_invoice_tax_name', 'easy_invoice_business_name', 'easy_invoice_business_address',
                'easy_invoice_invoice_number', 'easy_invoice_quote_number', 'easy_invoice_payment_gateway_paypal_email',
                'easy_invoice_terms_conditions', 'easy_invoice_quote_terms_conditions', 'easy_invoice_pre_defined_line_items',
                'easy_invoice_currency_symbol_type', 'easy_invoice_price_number_decimals', 'easy_invoice_decimal_separator',
                'easy_invoice_thousand_separator', 'easy_invoice_currency_position', 'easy_invoice_email_from_address',
                'easy_invoice_email_from_name', 'easy_invoice_email_send_admin_copy', 'easy_invoice_queue_flush_rewrite_rules',
                'easy_invoice_first_install_time', 'easy_invoice_payment_methods', 'easy_invoice_payment_gateway_order',
                'easy_invoice_payment_email_enabled', 'easy_invoice_payment_email_subject', 'easy_invoice_payment_email_body',
                'easy_invoice_payment_terms', 'easy_invoice_payment_reminder_days'
            ];

            // Count options using direct SQL query
            $option_placeholders = implode(',', array_fill(0, count($old_options), '%s'));
            $options_count = (int)$wpdb->get_var($wpdb->prepare(
                "SELECT COUNT(*) FROM {$wpdb->options} WHERE option_name IN ($option_placeholders)",
                $old_options
            ));

            wp_send_json_success([
                'invoices' => $invoice_count,
                'quotes' => $quote_count,
                'payments' => $payment_count,
                'options' => $options_count,
                'details' => [
                    'invoice_meta_count' => $invoice_meta_count,
                    'quote_meta_count' => $quote_meta_count,
                    'payment_meta_count' => $payment_meta_count
                ]
            ]);

        } catch (\Exception $e) {
            wp_send_json_error([
                'message' => $e->getMessage(),
            ]);
        }
    }

    /**
     * Handle AJAX cleanup request.
     *
     * @since 2.0.0
     * @return void
     */
    public static function handle_ajax_cleanup() {
        // Check nonce
        if (!wp_verify_nonce($_POST['nonce'], 'easy_invoice_migration_nonce')) {
            wp_die('Security check failed');
        }

        // Check permissions
        if (!current_user_can('manage_options')) {
            wp_die('Insufficient permissions');
        }

        try {
            $cleanup_options = isset($_POST['options']) ? (array)$_POST['options'] : [];
            $result = self::$migration_runner->run_migration_step('cleanup', $cleanup_options);

            if ($result['success']) {
                wp_send_json_success($result);
            } else {
                wp_send_json_error($result);
            }

        } catch (\Exception $e) {
            wp_send_json_error([
                'message' => $e->getMessage(),
            ]);
        }
    }

    /**
     * Register old post types temporarily.
     *
     * @since 2.0.0
     * @return void
     */
    private static function register_old_post_types() {
        // Only register if not already registered
        if (!post_type_exists('easy-invoice')) {
            register_post_type('easy-invoice', [
                'public' => false,
                'show_ui' => false,
                'capability_type' => 'post',
                'supports' => ['title', 'editor', 'custom-fields'],
                'can_export' => true
            ]);
        }

        if (!post_type_exists('easy-invoice-quotes')) {
            register_post_type('easy-invoice-quotes', [
                'public' => false,
                'show_ui' => false,
                'capability_type' => 'post',
                'supports' => ['title', 'editor', 'custom-fields'],
                'can_export' => true
            ]);
        }

        if (!post_type_exists('easy-invoice-payment')) {
            register_post_type('easy-invoice-payment', [
                'public' => false,
                'show_ui' => false,
                'capability_type' => 'post',
                'supports' => ['title', 'editor', 'custom-fields'],
                'can_export' => true
            ]);
        }
    }
}