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

namespace EasyInvoice\Migration\Src;

/**
 * Post type migration class.
 *
 * Handles migration of custom post types from old structure to new structure.
 *
 * @since 2.0.0
 */
class PostTypeMigration extends AbstractMigration {

    /**
     * Migration description.
     *
     * @since 2.0.0
     * @var string
     */
    protected $description = 'Migrate custom post types to new structure (preserves old data)';

    /**
     * Constructor.
     *
     * @since 2.0.0
     */
    public function __construct() {
        $this->register_old_post_types();
    }

    /**
     * Register old post types temporarily for migration.
     *
     * @since 2.0.0
     * @return void
     */
    private function register_old_post_types(): void {
        // Register old post types temporarily for migration
        foreach (array_keys($this->post_types) as $old_post_type) {
            if (!post_type_exists($old_post_type)) {
                register_post_type($old_post_type, [
                    'public' => false,
                    'show_ui' => false,
                    'capability_type' => 'post',
                    'supports' => ['title', 'editor', 'custom-fields'],
                    'can_export' => true
                ]);
            }
        }
    }

    /**
     * Post type mappings.
     * Maps old post types to new post types.
     *
     * @since 2.0.0
     * @var array
     */
    private $post_types = [
        'easy-invoice' => 'easy_invoice',
        'easy-invoice-quotes' => 'easy_invoice_quote',
        'easy-invoice-payment' => 'easy_invoice_payment'
    ];

    /**
     * Check if migration is needed.
     *
     * @since 2.0.0
     * @return bool
     */
    public function is_needed(): bool {
        global $wpdb;

        // Check if any old post types exist in the database
        foreach (array_keys($this->post_types) as $old_post_type) {
            $count = $wpdb->get_var(
                $wpdb->prepare(
                    "SELECT COUNT(*) FROM {$wpdb->posts} WHERE post_type = %s AND post_status NOT IN ('auto-draft', 'trash', 'inherit')",
                    $old_post_type
                )
            );

            if ($count > 0) {
                $this->log(sprintf('Found %d posts of type %s that need migration', $count, $old_post_type));
                    return true;
            }
        }

        return false;
    }

    /**
     * Run the migration.
     *
     * @since 2.0.0
     * @return array
     */
    public function migrate(): array {
        $this->log('Starting post type migration (preserving old data)');

        try {
            $migrated_count = 0;
            $errors = [];

            foreach ($this->post_types as $old_post_type => $new_post_type) {

                $result = $this->migrate_post_type($old_post_type, $new_post_type);

                if ($result['success']) {
                    $migrated_count += $result['count'];
                    $this->log(sprintf('Successfully migrated %d posts from %s to %s (old data preserved)', $result['count'], $old_post_type, $new_post_type));
                } else {
                    $errors[] = $result['message'];
                    $this->log(sprintf('Failed to migrate posts from %s: %s', $old_post_type, $result['message']), 'error');
                }
            }

            if (empty($errors)) {
                return $this->success_result(sprintf('Successfully migrated %d posts (old data preserved)', $migrated_count));
            } else {
                return $this->error_result('Post type migration completed with errors: ' . implode(', ', $errors));
            }

        } catch (\Exception $e) {
            $this->log('Post type migration failed: ' . $e->getMessage(), 'error');
            return $this->error_result('Post type migration failed: ' . $e->getMessage());
        }
    }

    /**
     * Migrate a specific post type.
     *
     * @since 2.0.0
     * @param string $old_post_type Old post type name.
     * @param string $new_post_type New post type name.
     * @return array
     */
    private function migrate_post_type(string $old_post_type, string $new_post_type): array {
        global $wpdb;

        // Direct database query to get posts since post type might not be registered
        $posts = $wpdb->get_results(
            $wpdb->prepare(
                "SELECT * FROM {$wpdb->posts} WHERE post_type = %s",
                $old_post_type
            )
        );

        if (empty($posts)) {
            return [
                'success' => true,
                'count' => 0,
                'message' => sprintf('No posts found for post type %s', $old_post_type),
            ];
        }

        $migrated_count = 0;
        $errors = [];
        $old_to_new_mapping = [];

        // First pass: Create new posts and store mappings
        foreach ($posts as $post) {
            $result = $this->migrate_single_post($post, $new_post_type);

            if ($result['success']) {
                $migrated_count++;
                $old_to_new_mapping[$post->ID] = $result['new_post_id'];
                $this->log(sprintf('Successfully migrated post %d to new post %d (type: %s)', $post->ID, $result['new_post_id'], $new_post_type));
            } else {
                $errors[] = sprintf('Post %d: %s', $post->ID, $result['message']);
            }
        }

        // Second pass: Update relationships using the mappings
        if (!empty($old_to_new_mapping)) {
            foreach ($old_to_new_mapping as $old_id => $new_id) {
                $this->update_relationships($old_id, $new_id, $new_post_type, $old_to_new_mapping);
            }
        }

        // Store migration summary for this post type
        $summary = [
            'old_post_type' => $old_post_type,
            'new_post_type' => $new_post_type,
            'migrated_count' => $migrated_count,
            'old_to_new_mapping' => $old_to_new_mapping,
            'completed_at' => current_time('mysql')
        ];
        update_option('easy_invoice_migration_summary_' . $old_post_type, $summary);

        if (empty($errors)) {
            return [
                'success' => true,
                'count' => $migrated_count,
                'message' => sprintf('Successfully migrated %d posts (old data preserved)', $migrated_count),
            ];
        } else {
            return [
                'success' => false,
                'count' => $migrated_count,
                'message' => 'Migration completed with errors: ' . implode(', ', $errors),
            ];
        }
    }

    /**
     * Migrate a single post.
     *
     * @since 2.0.0
     * @param object $post Post object from database query.
     * @param string $new_post_type New post type name.
     * @return array
     */
    private function migrate_single_post($post, string $new_post_type): array {
        try {
            global $wpdb;

            // Create new post with auto-generated ID
            $new_post_data = [
                'post_title' => $post->post_title,
                'post_content' => $post->post_content,
                'post_excerpt' => $post->post_excerpt,
                'post_status' => $post->post_status === 'publish' ? 'publish' : 'draft', // Ensure valid status
                'post_type' => $new_post_type,
                'post_author' => $post->post_author,
                'post_date' => $post->post_date,
                'post_date_gmt' => $post->post_date_gmt,
                'post_modified' => $post->post_modified,
                'post_modified_gmt' => $post->post_modified_gmt,
                'comment_status' => $post->comment_status,
                'ping_status' => $post->ping_status,
                'post_password' => $post->post_password,
                'post_name' => $post->post_name,
                'to_ping' => $post->to_ping,
                'pinged' => $post->pinged,
                'post_content_filtered' => $post->post_content_filtered,
                'post_parent' => $post->post_parent,
                'menu_order' => $post->menu_order,
                'post_mime_type' => $post->post_mime_type,
                'guid' => '', // Let WordPress generate new GUID
            ];

            // Insert new post
            $new_post_id = wp_insert_post($new_post_data, true);

            if (is_wp_error($new_post_id)) {
                return [
                    'success' => false,
                    'message' => $new_post_id->get_error_message(),
                ];
            }

            // Verify the post was actually created
            $new_post = get_post($new_post_id);
            if (!$new_post || $new_post->post_type !== $new_post_type) {
                return [
                    'success' => false,
                    'message' => sprintf('Failed to create new post of type %s', $new_post_type),
                ];
            }

            // Store mapping for reference (old ID -> new ID)
            update_option('easy_invoice_migration_post_mapping_' . $post->ID, $new_post_id);

            // Store original post ID in meta for reference
            update_post_meta($new_post_id, '_easy_invoice_original_post_id', $post->ID);
            update_post_meta($new_post_id, '_easy_invoice_original_post_type', $post->post_type);

            // Generate new invoice/quote numbers using the new plugin's numbering system
            $this->generate_new_numbers($new_post_id, $new_post_type);

            // Store mapping for reference (old ID -> new ID)
            update_option('easy_invoice_migration_post_mapping_' . $post->ID, $new_post_id);

            // Store original post ID in meta for reference
            update_post_meta($new_post_id, '_easy_invoice_original_post_id', $post->ID);
            update_post_meta($new_post_id, '_easy_invoice_original_post_type', $post->post_type);

            $this->log(sprintf('Successfully migrated post %d to new post %d (type: %s)', $post->ID, $new_post_id, $new_post_type));

            return [
                'success' => true,
                'message' => 'Post migrated successfully',
                'new_post_id' => $new_post_id,
            ];

        } catch (\Exception $e) {
            $this->log(sprintf('Failed to migrate post %d: %s', $post->ID, $e->getMessage()), 'error');
            return [
                'success' => false,
                'message' => $e->getMessage(),
            ];
        }
    }

    /**
     * Update relationships between posts.
     *
     * @since 2.0.0
     * @param int $old_id Old post ID
     * @param int $new_id New post ID
     * @param string $post_type Post type
     * @param array $mapping Mapping of old IDs to new IDs
     * @return void
     */
    private function update_relationships(int $old_id, int $new_id, string $post_type, array $mapping): void {
        global $wpdb;

        // Update client relationships
        if ($post_type === 'easy_invoice' || $post_type === 'easy_invoice_quote') {
            // Try different possible meta keys for client ID
            $possible_client_meta_keys = [
                '_client_id', 'client_id', '_invoice_client_id', '_quote_client_id',
                'easy_invoice_client_id', 'easy_invoice_quote_client_id',
                '_easy_invoice_client_id', '_easy_invoice_quote_client_id'
            ];
            $client_id = null;

            // First try to get client ID from meta
            foreach ($possible_client_meta_keys as $meta_key) {
                $client_id = get_post_meta($old_id, $meta_key, true);
                if (!empty($client_id)) {
                    break;
                }
            }

            // If no client ID in meta, try to get it from post meta table directly
            if (empty($client_id)) {
                foreach ($possible_client_meta_keys as $meta_key) {
                    $client_id = $wpdb->get_var($wpdb->prepare(
                        "SELECT meta_value FROM {$wpdb->postmeta} WHERE post_id = %d AND meta_key = %s",
                        $old_id,
                        $meta_key
                    ));
                    if (!empty($client_id)) {
                        break;
                    }
                }
            }

            if (!empty($client_id)) {
                // Get the WordPress user ID for this client
                $client_user_id = get_option('easy_invoice_client_user_mapping_' . $client_id, 0);

                // If no mapping found, try to find the client by email
                if ($client_user_id <= 0) {
                    // Try to get client email from old post meta
                    $possible_email_keys = [
                        '_client_email', 'client_email',
                                        'easy_invoice_client_email', 'easy_invoice_quote_client_email',
                '_easy_invoice_client_email', '_easy_invoice_quote_client_email'
                    ];

                    $client_email = null;
                    foreach ($possible_email_keys as $meta_key) {
                        $client_email = get_post_meta($old_id, $meta_key, true);
                        if (!empty($client_email)) {
                            break;
                        }
                    }

                    if (!empty($client_email)) {
                        $user = get_user_by('email', $client_email);
                        if ($user) {
                            $client_user_id = $user->ID;
                        }
                    }
                }

                if ($client_user_id > 0) {
                    $meta_prefix = $post_type === 'easy_invoice' ? '_easy_invoice' : '_easy_invoice_quote';

                    // Delete any existing client meta
                    $client_meta_keys = [
                        $meta_prefix . '_client_id',
                        $meta_prefix . '_client_name',
                        $meta_prefix . '_client_email',
                        $meta_prefix . '_client_company',
                        $meta_prefix . '_client_address',
                        $meta_prefix . '_client_phone',
                        $meta_prefix . '_client_vat'
                    ];
                    foreach ($client_meta_keys as $meta_key) {
                        delete_post_meta($new_id, $meta_key);
                    }

                    // Set new client ID
                    update_post_meta($new_id, $meta_prefix . '_client_id', $client_user_id);

                    // Get user data
                    $user = get_user_by('id', $client_user_id);
                    if ($user) {
                        // Get business name from user meta, fallback to display name
                        $business_name = get_user_meta($client_user_id, 'easy_invoice_business_client_name', true);
                        $client_name = !empty($business_name) ? $business_name : $user->display_name;

                        update_post_meta($new_id, $meta_prefix . '_client_name', $client_name);
                        update_post_meta($new_id, $meta_prefix . '_client_email', $user->user_email);

                        // Copy other client details from user meta
                        $client_fields = [
                            'company' => ['easy_invoice_company', 'company', '_company'],
                            'address' => ['easy_invoice_address', 'address', '_address'],
                            'phone' => ['easy_invoice_phone', 'phone', '_phone'],
                            'vat' => ['easy_invoice_vat', 'vat', '_vat']
                        ];

                        foreach ($client_fields as $field => $meta_keys) {
                            foreach ($meta_keys as $meta_key) {
                                $value = get_user_meta($client_user_id, $meta_key, true);
                                if (!empty($value)) {
                                    update_post_meta($new_id, $meta_prefix . '_client_' . $field, $value);
                                    break;
                                }
                            }
                        }

                        $this->log(sprintf('Updated client relationship for %s %d: Client ID %d -> User ID %d', $post_type, $new_id, $client_id, $client_user_id));
                    }
                } else {
                    $this->log(sprintf('Could not find WordPress user for client ID %d on %s %d', $client_id, $post_type, $new_id), 'warning');
                }
            } else {
                $this->log(sprintf('No client ID found for %s %d', $post_type, $new_id), 'warning');
            }
        }

        // Update payment relationships
        if ($post_type === 'easy_invoice_payment') {
            // Try different possible meta keys for invoice ID
            $possible_invoice_meta_keys = ['_invoice_id', 'invoice_id', '_payment_invoice_id'];
            $invoice_id = null;

            foreach ($possible_invoice_meta_keys as $meta_key) {
                $invoice_id = get_post_meta($old_id, $meta_key, true);
                if (!empty($invoice_id)) {
                    break;
                }
            }

            if (!empty($invoice_id)) {
                // Get the new invoice ID from the mapping
                $new_invoice_id = get_option('easy_invoice_migration_post_mapping_' . $invoice_id, 0);

                if ($new_invoice_id > 0) {
                    update_post_meta($new_id, '_easy_invoice_payment_invoice_id', $new_invoice_id);

                    // Copy invoice details to payment
                    $invoice_fields = [
                        'number' => '_easy_invoice_number',
                        'client_id' => '_easy_invoice_client_id',
                        'client_name' => '_easy_invoice_client_name',
                        'client_email' => '_easy_invoice_client_email',
                        'currency_code' => '_easy_invoice_currency_code',
                        'currency_symbol' => '_easy_invoice_currency_symbol'
                    ];

                    foreach ($invoice_fields as $field => $meta_key) {
                        $value = get_post_meta($new_invoice_id, $meta_key, true);
                        if (!empty($value)) {
                            update_post_meta($new_id, '_easy_invoice_payment_' . $field, $value);
                        }
                    }
                }
            }
        }
    }

    /**
     * Generate new invoice/quote numbers using the new plugin's numbering system.
     *
     * @since 2.0.0
     * @param int $post_id Post ID.
     * @param string $post_type Post type.
     * @return void
     */
    private function generate_new_numbers(int $post_id, string $post_type): void {
        try {
            if ($post_type === 'easy_invoice') {
                // Generate new invoice number
                if (class_exists('\\EasyInvoice\\Services\\InvoiceNumberService')) {
                    $invoice_service = new \EasyInvoice\Services\InvoiceNumberService();
                    $new_invoice_number = $invoice_service->generateUniqueNumber();

                    // Update the invoice number meta
                    update_post_meta($post_id, '_easy_invoice_number', $new_invoice_number);

                    $this->log(sprintf('Generated new invoice number: %s for post %d', $new_invoice_number, $post_id));
                }
            } elseif ($post_type === 'easy_invoice_quote') {
                // Generate new quote number
                if (class_exists('\\EasyInvoice\\Services\\QuoteNumberService')) {
                    $quote_service = new \EasyInvoice\Services\QuoteNumberService();
                    $new_quote_number = $quote_service->generateUniqueNumber();

                    // Update the quote number meta
                    update_post_meta($post_id, '_easy_invoice_quote_number', $new_quote_number);

                    $this->log(sprintf('Generated new quote number: %s for post %d', $new_quote_number, $post_id));
                }
            }
        } catch (\Exception $e) {
            $this->log(sprintf('Error generating new number for post %d: %s', $post_id, $e->getMessage()), 'error');
        }
    }
}