<?php
if (!defined('WPINC')) {
    die;
}

class Studiou_WC_FPP_Upload {

    /** @var Studiou_WC_FPP_DB */
    private $db;

    public function __construct($db) {
        $this->db = $db;
        add_action('wp_ajax_studiou_wcfpp_upload_chunk', array($this, 'handle_chunk_upload'));
        add_action('wp_ajax_nopriv_studiou_wcfpp_upload_chunk', array($this, 'handle_chunk_upload'));
        add_action('wp_ajax_studiou_wcfpp_remove_upload', array($this, 'handle_remove_upload'));
        add_action('wp_ajax_nopriv_studiou_wcfpp_remove_upload', array($this, 'handle_remove_upload'));
    }

    private function get_chunks_dir() {
        $upload_dir = wp_upload_dir();
        return $upload_dir['basedir'] . '/studiou-fpp-chunks';
    }

    private function get_allowed_mime_types() {
        return array(
            'jpg|jpeg|jpe' => 'image/jpeg',
            'png'          => 'image/png',
            'tiff|tif'     => 'image/tiff',
            'bmp'          => 'image/bmp',
            'psd'          => 'image/vnd.adobe.photoshop',
            'cr2'          => 'image/x-canon-cr2',
            'nef'          => 'image/x-nikon-nef',
            'arw'          => 'image/x-sony-arw',
            'dng'          => 'image/x-adobe-dng',
            'orf'          => 'image/x-olympus-orf',
            'rw2'          => 'image/x-panasonic-rw2',
            'raf'          => 'image/x-fuji-raf',
            'webp'         => 'image/webp',
        );
    }

    public function handle_chunk_upload() {
        // Clean output buffers
        while (ob_get_level()) {
            ob_end_clean();
        }

        check_ajax_referer('studiou-wcfpp-front-nonce', 'nonce');

        $product_id  = isset($_POST['product_id']) ? absint($_POST['product_id']) : 0;
        $upload_id   = isset($_POST['upload_id']) ? sanitize_text_field($_POST['upload_id']) : '';
        $chunk_index = isset($_POST['chunk_index']) ? absint($_POST['chunk_index']) : 0;
        $total_chunks = isset($_POST['total_chunks']) ? absint($_POST['total_chunks']) : 0;
        $file_name   = isset($_POST['file_name']) ? sanitize_file_name($_POST['file_name']) : '';
        $file_size   = isset($_POST['file_size']) ? absint($_POST['file_size']) : 0;

        // Validate product
        if (!$product_id || !Studiou_WC_FPP_Product::is_fpp_product($product_id)) {
            wp_send_json_error(array('message' => __('Invalid product.', 'studiou-wc-free-photo-product')));
            return;
        }

        // Validate file size
        $max_size = Studiou_WC_FPP_Product::get_product_max_file_size($product_id);
        if ($file_size > ($max_size * 1024 * 1024)) {
            wp_send_json_error(array('message' => sprintf(
                __('File is too large. Maximum size: %s MB', 'studiou-wc-free-photo-product'),
                $max_size
            )));
            return;
        }

        // Validate upload_id format (should be alphanumeric)
        if (!preg_match('/^[a-zA-Z0-9_-]+$/', $upload_id)) {
            wp_send_json_error(array('message' => __('Invalid upload ID.', 'studiou-wc-free-photo-product')));
            return;
        }

        // Validate chunk file exists
        if (!isset($_FILES['chunk']) || $_FILES['chunk']['error'] !== UPLOAD_ERR_OK) {
            wp_send_json_error(array('message' => __('Chunk upload failed.', 'studiou-wc-free-photo-product')));
            return;
        }

        $chunks_dir = $this->get_chunks_dir();
        if (!file_exists($chunks_dir)) {
            wp_mkdir_p($chunks_dir);
        }

        // Store the chunk
        $chunk_file = $chunks_dir . '/' . $upload_id . '_chunk_' . $chunk_index;
        if (!move_uploaded_file($_FILES['chunk']['tmp_name'], $chunk_file)) {
            wp_send_json_error(array('message' => __('Failed to store chunk.', 'studiou-wc-free-photo-product')));
            return;
        }

        // If this is the last chunk, assemble the file
        if ($chunk_index === $total_chunks - 1) {
            // Clean any output that may have been generated
            while (ob_get_level()) {
                ob_end_clean();
            }

            $result = $this->assemble_chunks($upload_id, $total_chunks, $file_name, $product_id);

            // Clean again before sending JSON
            while (ob_get_level()) {
                ob_end_clean();
            }

            if (is_wp_error($result)) {
                wp_send_json_error(array('message' => $result->get_error_message()));
                return;
            }

            wp_send_json_success(array(
                'complete'       => true,
                'attachment_id'  => $result['attachment_id'],
                'file_record_id' => $result['file_record_id'],
                'thumbnail_url'  => $result['thumbnail_url'],
                'preview_url'    => $result['preview_url'],
                'file_name'      => $result['file_name'],
            ));
            return;
        }

        wp_send_json_success(array(
            'complete'    => false,
            'chunk_index' => $chunk_index,
        ));
    }

    private function assemble_chunks($upload_id, $total_chunks, $file_name, $product_id) {
        $chunks_dir = $this->get_chunks_dir();
        $upload_dir = wp_upload_dir();

        // Create a subdirectory for free photo uploads
        $fpp_dir = $upload_dir['path'] . '/free-photo';
        if (!file_exists($fpp_dir)) {
            wp_mkdir_p($fpp_dir);
        }

        // Generate unique filename
        $ext = pathinfo($file_name, PATHINFO_EXTENSION);
        $base = sanitize_file_name(pathinfo($file_name, PATHINFO_FILENAME));
        $unique_name = $base . '_' . uniqid() . '.' . $ext;
        $assembled_path = $fpp_dir . '/' . $unique_name;

        // Assemble chunks
        $output = fopen($assembled_path, 'wb');
        if (!$output) {
            $this->cleanup_chunks($upload_id, $total_chunks);
            return new WP_Error('assemble_failed', __('Failed to create output file.', 'studiou-wc-free-photo-product'));
        }

        for ($i = 0; $i < $total_chunks; $i++) {
            $chunk_file = $chunks_dir . '/' . $upload_id . '_chunk_' . $i;
            if (!file_exists($chunk_file)) {
                fclose($output);
                unlink($assembled_path);
                $this->cleanup_chunks($upload_id, $total_chunks);
                return new WP_Error('chunk_missing', sprintf(
                    __('Missing chunk %d.', 'studiou-wc-free-photo-product'),
                    $i
                ));
            }

            $chunk_data = file_get_contents($chunk_file);
            fwrite($output, $chunk_data);
        }
        fclose($output);

        // Clean up chunk files
        $this->cleanup_chunks($upload_id, $total_chunks);

        // Validate file extension
        $allowed = $this->get_allowed_mime_types();
        $ext_lower = strtolower($ext);
        $valid = false;
        foreach ($allowed as $exts => $mime) {
            $ext_list = explode('|', $exts);
            if (in_array($ext_lower, $ext_list)) {
                $valid = true;
                break;
            }
        }
        if (!$valid) {
            unlink($assembled_path);
            return new WP_Error('invalid_type', __('File type not allowed.', 'studiou-wc-free-photo-product'));
        }

        // Create WP attachment
        $relative_path = str_replace($upload_dir['basedir'] . '/', '', $assembled_path);
        $filetype = wp_check_filetype($unique_name, $allowed);

        $attachment_data = array(
            'post_mime_type' => $filetype['type'] ?: 'application/octet-stream',
            'post_title'     => sanitize_file_name($file_name),
            'post_content'   => '',
            'post_status'    => 'inherit',
            'post_parent'    => $product_id,
        );

        $attachment_id = wp_insert_attachment($attachment_data, $assembled_path, $product_id);
        if (is_wp_error($attachment_id)) {
            unlink($assembled_path);
            return $attachment_id;
        }

        // Generate metadata (wrapped in output buffer to prevent stray output corrupting JSON)
        require_once(ABSPATH . 'wp-admin/includes/image.php');
        ob_start();
        try {
            @set_time_limit(120);
            $metadata = @wp_generate_attachment_metadata($attachment_id, $assembled_path);
            if (!empty($metadata)) {
                wp_update_attachment_metadata($attachment_id, $metadata);
            }
        } catch (\Throwable $e) {
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU FPP: metadata generation failed - ' . $e->getMessage());
            }
        }
        ob_end_clean();

        // Assign media category
        $media_cat_id = Studiou_WC_FPP_Product::get_product_media_category($product_id);
        if ($media_cat_id) {
            wp_set_object_terms($attachment_id, array((int) $media_cat_id), 'studiou_media_category');
        }

        // Get thumbnail URL (small - for upload preview)
        $thumbnail_url = '';
        $image_src = wp_get_attachment_image_src($attachment_id, 'thumbnail');
        if ($image_src) {
            $thumbnail_url = $image_src[0];
        } else {
            $thumbnail_url = wp_mime_type_icon($attachment_id);
        }

        // Get preview URL (larger - for product gallery replacement)
        $preview_url = '';
        $preview_src = wp_get_attachment_image_src($attachment_id, 'woocommerce_single');
        if ($preview_src) {
            $preview_url = $preview_src[0];
        } elseif ($image_src) {
            $preview_url = $image_src[0];
        }

        // Get session key for guests
        $session_key = '';
        if (!is_user_logged_in()) {
            if (WC()->session) {
                $session_key = WC()->session->get_customer_id();
            }
        }

        // Insert file record
        $file_record_id = $this->db->insert_file_record(array(
            'product_id'    => $product_id,
            'attachment_id' => $attachment_id,
            'customer_id'   => get_current_user_id(),
            'session_key'   => $session_key,
            'file_name'     => $file_name,
        ));

        if (!$file_record_id) {
            wp_delete_attachment($attachment_id, true);
            return new WP_Error('record_failed', __('Failed to create file record.', 'studiou-wc-free-photo-product'));
        }

        return array(
            'attachment_id'  => $attachment_id,
            'file_record_id' => $file_record_id,
            'thumbnail_url'  => $thumbnail_url,
            'preview_url'    => $preview_url,
            'file_name'      => $file_name,
        );
    }

    private function cleanup_chunks($upload_id, $total_chunks) {
        $chunks_dir = $this->get_chunks_dir();
        for ($i = 0; $i < $total_chunks; $i++) {
            $chunk_file = $chunks_dir . '/' . $upload_id . '_chunk_' . $i;
            if (file_exists($chunk_file)) {
                unlink($chunk_file);
            }
        }
    }

    public function handle_remove_upload() {
        check_ajax_referer('studiou-wcfpp-front-nonce', 'nonce');

        $file_record_id = isset($_POST['file_record_id']) ? absint($_POST['file_record_id']) : 0;
        if (!$file_record_id) {
            wp_send_json_error(array('message' => __('Invalid file.', 'studiou-wc-free-photo-product')));
            return;
        }

        $record = $this->db->get_file_record($file_record_id);
        if (!$record) {
            wp_send_json_error(array('message' => __('File not found.', 'studiou-wc-free-photo-product')));
            return;
        }

        // Only allow removal if not yet linked to an order
        if ($record->order_id > 0) {
            wp_send_json_error(array('message' => __('Cannot remove a file linked to an order.', 'studiou-wc-free-photo-product')));
            return;
        }

        // Verify ownership
        $current_user_id = get_current_user_id();
        if ($current_user_id > 0 && (int) $record->customer_id !== $current_user_id) {
            wp_send_json_error(array('message' => __('Permission denied.', 'studiou-wc-free-photo-product')));
            return;
        }

        $this->db->delete_file_record($file_record_id);

        wp_send_json_success(array('message' => __('File removed.', 'studiou-wc-free-photo-product')));
    }
}