<?php
if ( ! defined( 'ABSPATH' ) ) exit;

class VV_Helpers {

    public static function is_vendor( $user_id = null ) {
        if ( ! $user_id ) $user_id = get_current_user_id();
        return get_user_meta( $user_id, 'vv_user_role', true ) === 'Vendor';
    }

    public static function get_vendor_balance( $user_id ) {
        global $wpdb;
        $credit = (float) $wpdb->get_var( $wpdb->prepare(
            "SELECT COALESCE(SUM(amount),0) FROM {$wpdb->prefix}vv_wallet_transactions WHERE user_id=%d AND type='credit'", $user_id
        ) );
        $debit = (float) $wpdb->get_var( $wpdb->prepare(
            "SELECT COALESCE(SUM(amount),0) FROM {$wpdb->prefix}vv_wallet_transactions WHERE user_id=%d AND type='debit'", $user_id
        ) );
        return round( $credit - $debit, 2 );
    }

    public static function record_transaction( $user_id, $amount, $type, $description, $product_id = 0, $order_id = 0 ) {
        global $wpdb;
        return $wpdb->insert( "{$wpdb->prefix}vv_wallet_transactions", [
            'user_id'     => $user_id,
            'amount'      => $amount,
            'type'        => $type,
            'description' => $description,
            'product_id'  => $product_id,
            'order_id'    => $order_id,
        ] );
    }

    public static function get_vendor_stats( $vendor_id ) {
        $cache_key = 'vv_vendor_stats_' . $vendor_id;
        $stats = wp_cache_get( $cache_key, 'vendorverse' );
        if ( false !== $stats ) return $stats;

        global $wpdb;
        $stats = [
            'total_products'    => (int) $wpdb->get_var( $wpdb->prepare(
                "SELECT COUNT(*) FROM {$wpdb->prefix}posts WHERE post_author=%d AND post_type='product' AND post_status='publish'", $vendor_id
            ) ),
            'total_orders'      => (int) $wpdb->get_var( $wpdb->prepare(
                "SELECT COUNT(DISTINCT order_id) FROM {$wpdb->prefix}vv_system_orders WHERE product_owner_user_id=%d", $vendor_id
            ) ),
            'total_earnings'    => (float) $wpdb->get_var( $wpdb->prepare(
                "SELECT COALESCE(SUM(amount),0) FROM {$wpdb->prefix}vv_wallet_transactions WHERE user_id=%d AND type='credit'", $vendor_id
            ) ),
            'balance'           => self::get_vendor_balance( $vendor_id ),
            'avg_rating'        => (float) $wpdb->get_var( $wpdb->prepare(
                "SELECT COALESCE(AVG(rating),0) FROM {$wpdb->prefix}vv_vendor_reviews WHERE vendor_id=%d", $vendor_id
            ) ),
            'review_count'      => (int) $wpdb->get_var( $wpdb->prepare(
                "SELECT COUNT(*) FROM {$wpdb->prefix}vv_vendor_reviews WHERE vendor_id=%d", $vendor_id
            ) ),
            'follower_count'    => (int) $wpdb->get_var( $wpdb->prepare(
                "SELECT COUNT(*) FROM {$wpdb->prefix}vv_followers WHERE vendor_id=%d", $vendor_id
            ) ),
        ];

        wp_cache_set( $cache_key, $stats, 'vendorverse', HOUR_IN_SECONDS );
        return $stats;
    }

    public static function flush_vendor_cache( $vendor_id ) {
        wp_cache_delete( 'vv_vendor_stats_' . $vendor_id, 'vendorverse' );
    }

    public static function get_commission_rate( $vendor_id, $product_id = null ) {
        // Vendor-specific override
        $vendor_rate = get_user_meta( $vendor_id, 'vv_commission_rate', true );
        if ( $vendor_rate !== '' && is_numeric( $vendor_rate ) ) {
            return (float) $vendor_rate;
        }
        // Product-specific override
        if ( $product_id ) {
            $product_rate = get_post_meta( $product_id, '_vv_commission_rate', true );
            if ( $product_rate !== '' && is_numeric( $product_rate ) ) {
                return (float) $product_rate;
            }
        }
        // Tiered commission by lifetime sales
        $total_sales = (float) self::get_vendor_stats( $vendor_id )['total_orders'];
        if ( $total_sales >= 200 ) return (float) get_option( 'vv_commission_tier3', 5 );
        if ( $total_sales >= 50 )  return (float) get_option( 'vv_commission_tier2', 8 );
        return (float) get_option( 'vv_commission_rate', 10 );
    }

    public static function currency( $amount ) {
        return wc_price( $amount );
    }

    public static function sales_chart_data( $vendor_id, $days = 30 ) {
        global $wpdb;
        $rows = $wpdb->get_results( $wpdb->prepare(
            "SELECT DATE(t.created_at) AS day, SUM(t.amount) AS total
             FROM {$wpdb->prefix}vv_wallet_transactions t
             WHERE t.user_id = %d AND t.type = 'credit'
               AND t.created_at >= DATE_SUB(NOW(), INTERVAL %d DAY)
             GROUP BY DATE(t.created_at)
             ORDER BY day ASC",
            $vendor_id, $days
        ) );
        $labels = $data = [];
        foreach ( $rows as $r ) {
            $labels[] = date( 'M j', strtotime( $r->day ) );
            $data[]   = (float) $r->total;
        }
        return [ 'labels' => $labels, 'data' => $data ];
    }

    public static function allowed_file_types() {
        return [
            'jpg|jpeg|jpe' => 'image/jpeg',
            'gif'          => 'image/gif',
            'png'          => 'image/png',
            'webp'         => 'image/webp',
            'pdf'          => 'application/pdf',
            'zip'          => 'application/zip',
            'mp3'          => 'audio/mpeg',
            'mp4'          => 'video/mp4',
        ];
    }

    public static function nonce_field( $action = 'vv_action' ) {
        wp_nonce_field( $action, 'vv_nonce' );
    }

    public static function verify_nonce( $action = 'vv_action' ) {
        if ( empty( $_POST['vv_nonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['vv_nonce'] ) ), $action ) ) {
            wp_die( esc_html__( 'Security check failed.', 'vendorverse' ) );
        }
    }
}