<?php

namespace Better_Payment\Lite\Classes;

use Better_Payment\Lite\Admin\DB;
use Better_Payment\Lite\Controller;
use Better_Payment\Lite\Models\TransactionModel;
use Better_Payment\Lite\Traits\Helper;
use Exception;
use League\Csv\Reader;
use League\Csv\Statement;

/**
 * Exit if accessed directly
 */
if (!defined('ABSPATH')) {
    exit;
}

/**
 * Export handler class
 * 
 * @since 0.0.4
 */
class Import extends Controller{

    use Helper;
    /**
     * Class constructor
     * 
     * @since 0.0.4
     */
    public function __construct() {
        
    }

    /**
     * Decode a CSV `form_fields_info` cell into an array.
     *
     * The cell comes from an uploaded file, so it is never handed to maybe_unserialize():
     * that instantiates any class a serialized payload names, which turns an import into an
     * object-injection sink for whatever gadget chain the site's plugins happen to provide.
     * Objects are refused outright; only a plain array survives.
     *
     * @since 2.3.4
     *
     * @param mixed $value Cell value.
     * @return array
     */
    public static function decode_form_fields_info( $value ) {
        if ( ! is_string( $value ) || ! is_serialized( $value ) ) {
            return [];
        }

        // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.serialize_unserialize, WordPress.PHP.NoSilencedErrors.Discouraged -- classes are disallowed; a malformed cell is expected input.
        $decoded = @unserialize( trim( $value ), [ 'allowed_classes' => false ] );

        return is_array( $decoded ) ? $decoded : [];
    }

    public function import_transactions() {
        $message = __('Invalid File!', 'better-payment');
        
        $invalid_nonce  = ! wp_verify_nonce( $_REQUEST['nonce'], 'better_payment_transaction_import_nonce' );
        $invalid_access = ! current_user_can('manage_options') || ! isset( $_FILES['better-payment-transaction-import-input'] ); 

		if ( $invalid_nonce || $invalid_access ) {
            set_transient('better_payment_import_transactions_error', esc_html( $message ), 30);
            wp_safe_redirect( $_SERVER['HTTP_REFERER'] );
            exit;
		}

        $file = $_FILES['better-payment-transaction-import-input'];
        
        try {
            $this->validate_csv_file($file);
            $csv = Reader::createFromPath($file['tmp_name'], 'r');
            $csv->setHeaderOffset(0);
            
            // Header validation
            $csvHeader = $csv->getHeader();
            if ( isset( $csvHeader[0] ) && false !== strpos( $csvHeader[0], ';' ) ) {
                $csv->setDelimiter(';');
                $csvHeader = $csv->getHeader();
            }

            if ( ! is_array( $csvHeader ) || ! count( $csvHeader) ){
                throw new Exception( $message );
            }

            $csvHeader = array_map('sanitize_text_field', $csvHeader);
            
            $exportObj = new Export();
            $allowedHeaders = $exportObj->export_transactions_heading();

            if ( count( $allowedHeaders ) !== count( $csvHeader ) ) {
                throw new Exception( $message );
            }

            // Fetch rows
            $stmt = Statement::create()->offset(0)->limit(3000);
            $records = $stmt->process($csv);

            $data = array();

            foreach ( $records as $record ) {
                $better_form_fields = $this->build_form_fields( $record );

                $amount_currency_array = explode(' ', $record['amount']);
                $currency = is_array($amount_currency_array) && count($amount_currency_array) > 1 ? $amount_currency_array[0] : esc_html('USD');
                $amount = is_array($amount_currency_array) && count($amount_currency_array) > 1 ? $amount_currency_array[1] : $record['amount'];

                $data[] = array(
                    'email'             => sanitize_email( $record['email'] ),
                    'currency'          => sanitize_text_field( $currency ),
                    'amount'            => floatval( $amount ),
                    // 'payment_type'      => sanitize_text_field( $record['payment_type'] ),
                    'transaction_id'    => sanitize_text_field( $record['transaction_id'] ),
                    'source'            => sanitize_text_field( $record['source'] ),
                    'status'            => sanitize_text_field( $record['status'] ),
                    'payment_date'      => date( 'Y-m-d H:i:s', strtotime( sanitize_text_field( $record['payment_date'] ) ) ),
                    'form_fields_info'  => maybe_serialize( $better_form_fields ),
                );
            }

            if ( empty( $data ) ) {
                throw new Exception( __('No valid records found in the CSV file!', 'better-payment') );
            }

            $table = DB::get_table_name();
            $rowsInserted = $this->bulk_insert_transactions( $table, $data );
            if ( $rowsInserted !== false && $rowsInserted > 0 ) {
                set_transient('better_payment_import_transactions_success', esc_html__( $rowsInserted . ' rows inserted successfully!', 'better-payment' ), 30);
            } else {
                throw new Exception( __('Failed to insert records into database!', 'better-payment') );
            }
        } catch (\Exception $exception) {
            set_transient('better_payment_import_transactions_error', esc_html( $exception->getMessage() ), 30);
            wp_safe_redirect( $_SERVER['HTTP_REFERER'] );
            exit;
        }

        wp_safe_redirect( $_SERVER['HTTP_REFERER'] );
        exit;
    }

    /**
     * The `form_fields_info` an imported CSV row is stored with.
     *
     * Lite keeps the name, email and source and marks the row imported.
     * `better_payment/import/form_fields_info` receives that, the CSV row and the
     * row's decoded `form_fields_info` cell: Pro adds the subscription keys of a
     * "Subscription" row there. Lite's copy of that
     * (ProSubscriptionTransactionData::import_fields()) serves only an active Pro
     * that does not (<= 1.4.3).
     *
     * @since 2.4.0
     *
     * @param mixed $record CSV row keyed by header; anything else is treated as empty.
     * @return array
     */
    public function build_form_fields( $record ) {
        $record = is_array( $record ) ? $record : [];

        $better_form_fields = [
            'primary_first_name'    => sanitize_text_field( $record['name'] ?? '' ),
            'email'                 => sanitize_email( $record['email'] ?? '' ),
            'source'                => sanitize_text_field( $record['source'] ?? '' ),
            'is_imported'           => intval(1),
        ];

        // Decoded without instantiating objects; see decode_form_fields_info().
        $decoded = isset( $record['form_fields_info'] ) ? self::decode_form_fields_info( $record['form_fields_info'] ) : [];

        if ( ProSubscriptionTransactionData::lite_copy_applies() ) {
            $better_form_fields = ProSubscriptionTransactionData::import_fields( $better_form_fields, $record, $decoded );
        }

        $filtered = apply_filters( 'better_payment/import/form_fields_info', $better_form_fields, $record, $decoded );

        return is_array( $filtered ) ? $filtered : $better_form_fields;
    }

    public function validate_csv_file( $file ){
        $message = __('Invalid File!', 'better-payment');

        if ( empty( $file ) ){
            throw new Exception( $message );
        }

        $extension = pathinfo( $file['name'], PATHINFO_EXTENSION );
        $allowed_extensions = ['csv'];

        if ( empty( $extension ) || ! in_array( $extension, $allowed_extensions ) ) {
            throw new Exception( $message );
        }

        return true;
    }

    public function bulk_insert_transactions($table, $rows) {
        global $wpdb;

        $headers = array_keys($rows[0]);
        asort($headers);
        $columnList = '`' . implode('`, `', $headers) . '`';

        $sql          = "INSERT INTO `$table` ($columnList) VALUES\n";
        $placeholders = array();
        $data         = array();
        
        foreach ($rows as $row) {
            ksort($row);
            $rowPlaceholders = array();
            foreach ($row as $value) {
                $data[]            = $value;
                $rowPlaceholders[] = is_numeric($value) ? '%d' : '%s';
            }
            $placeholders[] = '(' . implode(', ', $rowPlaceholders) . ')';
        }

        $sql .= implode(",\n", $placeholders);
        
        $rowsInserted = $wpdb->query($wpdb->prepare($sql, $data));
        return $rowsInserted;
    }
}