<?php
declare(strict_types=1);
header('Content-Type: application/json; charset=utf-8');

if (session_status() == PHP_SESSION_NONE) {
    session_start();
}

require_once __DIR__ . '/../config/config.php';

try {
    $pdo = new PDO(
        "mysql:host=" . DB_HOST . ";dbname=" . DB_NAME . ";charset=utf8mb4",
        DB_USER,
        DB_PASS,
        [
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        ]
    );
    
    $pdo->exec("SET time_zone = '+05:30'");
    
} catch (PDOException $e) {
    echo json_encode(['success' => false, 'message' => 'Database connection failed']);
    exit;
}

// ============================================
// ✅ CHECK OFFER STATUS (for polling)
// ============================================
if (isset($_POST['action']) && $_POST['action'] === 'check_offer_status') {
    $productId = isset($_POST['product_id']) ? (int)$_POST['product_id'] : 0;
    
    if ($productId <= 0 || !isset($_SESSION['user_id'])) {
        echo json_encode(['success' => false, 'message' => 'Invalid request']);
        exit;
    }
    
    $userId = (int)$_SESSION['user_id'];
    
    try {
        $checkSql = "SELECT offer_id, offer_amount, status, offer_valid_until,
                     CASE 
                         WHEN status = 'accepted' AND offer_valid_until < NOW() THEN 1
                         ELSE 0
                     END as is_expired
                     FROM tbl_offers 
                     WHERE user_id = :user_id 
                     AND product_id = :product_id 
                     ORDER BY created_at DESC
                     LIMIT 1";
        
        $stmt = $pdo->prepare($checkSql);
        $stmt->execute([':user_id' => $userId, ':product_id' => $productId]);
        
        $offer = $stmt->fetch();
        
        if ($offer) {
            echo json_encode([
                'success' => true,
                'has_offer' => true,
                'offer_status' => $offer['status'],
                'offer_amount' => $offer['offer_amount'],
                'offer_valid_until' => $offer['offer_valid_until'],
                'is_expired' => (bool)$offer['is_expired']
            ]);
        } else {
            echo json_encode([
                'success' => true,
                'has_offer' => false,
                'offer_status' => null
            ]);
        }
        
    } catch (PDOException $e) {
        error_log('Check offer status error: ' . $e->getMessage());
        echo json_encode(['success' => false, 'message' => 'Database error']);
    }
    
    exit;
}

// ============================================
// ✅ ARCHIVE EXPIRED OFFERS HANDLER
// ============================================
if (isset($_POST['action']) && $_POST['action'] === 'archive_expired') {
    try {
        $pdo->exec("SET time_zone = '+05:30'");
        
        // Create archive table if not exists
        $checkTableSql = "SHOW TABLES LIKE 'tbl_offers_archive'";
        $tableExists = $pdo->query($checkTableSql)->rowCount() > 0;
        
        if (!$tableExists) {
            $createTableSql = "CREATE TABLE IF NOT EXISTS tbl_offers_archive (
                archive_id INT AUTO_INCREMENT PRIMARY KEY,
                offer_id INT NOT NULL,
                product_id INT,
                variant_id INT,
                variant_title VARCHAR(255),
                variant_attributes TEXT,
                user_name VARCHAR(255),
                user_email VARCHAR(255),
                user_phone VARCHAR(20),
                offer_amount DECIMAL(10,2),
                status VARCHAR(50),
                rejection_reason TEXT,
                offer_valid_until DATETIME,
                created_at DATETIME,
                updated_at DATETIME,
                archived_at DATETIME DEFAULT CURRENT_TIMESTAMP,
                expiration_reason VARCHAR(100),
                INDEX idx_offer_id (offer_id),
                INDEX idx_archived_at (archived_at),
                INDEX idx_user_email (user_email),
                INDEX idx_product_id (product_id)
            ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4";
            
            $pdo->exec($createTableSql);
        }
        
        // Find expired offers
        $findExpiredSql = "SELECT o.*, p.pname as product_name 
                          FROM tbl_offers o 
                          LEFT JOIN products p ON o.product_id = p.pid 
                          WHERE o.status = 'accepted' 
                          AND o.offer_valid_until IS NOT NULL 
                          AND o.offer_valid_until <= NOW()";
        
        $findStmt = $pdo->query($findExpiredSql);
        $expiredOffers = $findStmt->fetchAll();
        
        $archivedCount = 0;
        $expiredIds = [];
        
        foreach ($expiredOffers as $offer) {
            $variantAttributes = $offer['variant_attributes'] ?? '';
            if (is_array($variantAttributes)) {
                $variantAttributes = json_encode($variantAttributes);
            }
            
            $archiveSql = "INSERT INTO tbl_offers_archive 
                          (offer_id, product_id, variant_id, variant_title, variant_attributes,
                           user_name, user_email, user_phone, offer_amount, 
                           status, rejection_reason, offer_valid_until, 
                           created_at, updated_at, expiration_reason) 
                          VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 'Offer validity expired')";
            
            $archiveStmt = $pdo->prepare($archiveSql);
            $success = $archiveStmt->execute([
                $offer['offer_id'],
                $offer['product_id'],
                $offer['variant_id'] ?? null,
                $offer['variant_title'] ?? '',
                $variantAttributes,
                $offer['user_name'] ?? '',
                $offer['user_email'] ?? '',
                $offer['user_phone'] ?? '',
                $offer['offer_amount'],
                $offer['status'],
                $offer['rejection_reason'] ?? null,
                $offer['offer_valid_until'],
                $offer['created_at'],
                $offer['updated_at'] ?? date('Y-m-d H:i:s')
            ]);
            
            if ($success) {
                $deleteSql = "DELETE FROM tbl_offers WHERE offer_id = ?";
                $deleteStmt = $pdo->prepare($deleteSql);
                $deleteStmt->execute([$offer['offer_id']]);
                
                $expiredIds[] = $offer['offer_id'];
                $archivedCount++;
                
                error_log("✅ Archived expired offer #" . $offer['offer_id']);
            }
        }
        
        echo json_encode([
            'success' => true,
            'archived_count' => $archivedCount,
            'expired_ids' => $expiredIds,
            'message' => $archivedCount > 0 
                ? "$archivedCount offer(s) archived successfully" 
                : "No expired offers found"
        ]);
        exit;
        
    } catch (PDOException $e) {
        error_log('Archive error: ' . $e->getMessage());
        echo json_encode([
            'success' => false, 
            'message' => 'Archive failed: ' . $e->getMessage()
        ]);
        exit;
    }
}

// ============================================
// ✅ DELETE EXPIRED OFFER (Client-side cleanup)
// ============================================
// ============================================
// ✅ DELETE EXPIRED OFFER (Client-side cleanup) - NOW WITH ARCHIVING
// ============================================
if (isset($_POST['action']) && $_POST['action'] === 'delete_expired_offer') {
    $productId = isset($_POST['product_id']) ? (int)$_POST['product_id'] : (int)($_POST['pid'] ?? 0);
    
    if ($productId <= 0) {
        echo json_encode(['success' => false, 'message' => 'Invalid product ID']);
        exit;
    }
    
    try {
        if (isset($_SESSION['user_id'])) {
            $userId = (int)$_SESSION['user_id'];
            
            // ✅ STEP 1: Get the expired offer before deleting
            $selectSql = "SELECT o.*, p.pname as product_name 
                          FROM tbl_offers o 
                          LEFT JOIN products p ON o.product_id = p.pid 
                          WHERE o.user_id = :user_id 
                          AND o.product_id = :product_id 
                          AND o.offer_valid_until < NOW()";
            
            $selectStmt = $pdo->prepare($selectSql);
            $selectStmt->execute([
                ':user_id' => $userId,
                ':product_id' => $productId
            ]);
            
            $expiredOffer = $selectStmt->fetch();
            
            if ($expiredOffer) {
                // ✅ STEP 2: Create archive table if not exists
                $checkTableSql = "SHOW TABLES LIKE 'tbl_offers_archive'";
                $tableExists = $pdo->query($checkTableSql)->rowCount() > 0;
                
                if (!$tableExists) {
                    $createTableSql = "CREATE TABLE IF NOT EXISTS tbl_offers_archive (
                        archive_id INT AUTO_INCREMENT PRIMARY KEY,
                        offer_id INT NOT NULL,
                        product_id INT,
                        variant_id INT,
                        variant_title VARCHAR(255),
                        variant_attributes TEXT,
                        user_name VARCHAR(255),
                        user_email VARCHAR(255),
                        user_phone VARCHAR(20),
                        offer_amount DECIMAL(10,2),
                        status VARCHAR(50),
                        rejection_reason TEXT,
                        offer_valid_until DATETIME,
                        created_at DATETIME,
                        updated_at DATETIME,
                        archived_at DATETIME DEFAULT CURRENT_TIMESTAMP,
                        expiration_reason VARCHAR(100),
                        INDEX idx_offer_id (offer_id),
                        INDEX idx_archived_at (archived_at),
                        INDEX idx_user_email (user_email),
                        INDEX idx_product_id (product_id)
                    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4";
                    
                    $pdo->exec($createTableSql);
                }
                
                // ✅ STEP 3: Archive the offer
                $variantAttributes = $expiredOffer['variant_attributes'] ?? '';
                if (is_array($variantAttributes)) {
                    $variantAttributes = json_encode($variantAttributes);
                }
                
                $archiveSql = "INSERT INTO tbl_offers_archive 
                              (offer_id, product_id, variant_id, variant_title, variant_attributes,
                               user_name, user_email, user_phone, offer_amount, 
                               status, rejection_reason, offer_valid_until, 
                               created_at, updated_at, expiration_reason) 
                              VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 'Offer validity expired - client cleanup')";
                
                $archiveStmt = $pdo->prepare($archiveSql);
                $archiveStmt->execute([
                    $expiredOffer['offer_id'],
                    $expiredOffer['product_id'],
                    $expiredOffer['variant_id'] ?? null,
                    $expiredOffer['variant_title'] ?? '',
                    $variantAttributes,
                    $expiredOffer['user_name'] ?? '',
                    $expiredOffer['user_email'] ?? '',
                    $expiredOffer['user_phone'] ?? '',
                    $expiredOffer['offer_amount'],
                    $expiredOffer['status'],
                    $expiredOffer['rejection_reason'] ?? null,
                    $expiredOffer['offer_valid_until'],
                    $expiredOffer['created_at'],
                    $expiredOffer['updated_at'] ?? date('Y-m-d H:i:s')
                ]);
                
                error_log("✅ Archived expired offer #" . $expiredOffer['offer_id']);
            }
            
            // ✅ STEP 4: Now delete the offer
            $deleteSql = "DELETE FROM tbl_offers 
                          WHERE user_id = :user_id 
                          AND product_id = :product_id 
                          AND offer_valid_until < NOW()";
            
            $deleteStmt = $pdo->prepare($deleteSql);
            $deleteStmt->execute([
                ':user_id' => $userId,
                ':product_id' => $productId
            ]);
            
            $rowsDeleted = $deleteStmt->rowCount();
            
            echo json_encode([
                'success' => true, 
                'message' => 'Expired offer archived and deleted',
                'rows_deleted' => $rowsDeleted,
                'archived' => !empty($expiredOffer)
            ]);
        } else {
            echo json_encode(['success' => false, 'message' => 'User not logged in']);
        }
        exit;
        
    } catch (PDOException $e) {
        error_log('Delete expired offer error: ' . $e->getMessage());
        echo json_encode(['success' => false, 'message' => 'Database error']);
        exit;
    }
}

// ============================================
// SEND ADMIN EMAIL NOTIFICATION
// ============================================
function sendAdminOfferNotification($product_name, $variant_title, $user_name, $user_email, $offer_amount, $product_id, $offer_id) {
    try {
        $possible_paths = [
            '../vendor/autoload.php',
            '../../../vendor/autoload.php',
            '../../vendor/autoload.php',
            dirname(__DIR__) . '/vendor/autoload.php'
        ];
        
        $autoloader_found = false;
        foreach ($possible_paths as $path) {
            if (file_exists($path)) {
                require_once $path;
                $autoloader_found = true;
                break;
            }
        }
        
        if (!$autoloader_found || !class_exists('PHPMailer\PHPMailer\PHPMailer')) {
            error_log("PHPMailer not found");
            return false;
        }
        
        $mail = new PHPMailer\PHPMailer\PHPMailer(true);
        
        $mail->isSMTP();
        $mail->Host = SMTP_HOST;
        $mail->SMTPAuth = true;
        $mail->Username = SMTP_USERNAME;
        $mail->Password = SMTP_PASSWORD;
        $mail->SMTPSecure = PHPMailer\PHPMailer\PHPMailer::ENCRYPTION_STARTTLS;
        $mail->Port = defined('SMTP_PORT') ? SMTP_PORT : 587;
        
        $from_email = defined('SMTP_FROM_EMAIL') ? SMTP_FROM_EMAIL : SMTP_USERNAME;
        $from_name = defined('SMTP_FROM_NAME') ? SMTP_FROM_NAME : 'TDS Marketplace';
        
        $mail->setFrom($from_email, $from_name);
        
        if (defined('ADMIN_EMAIL') && !empty(ADMIN_EMAIL)) {
            $mail->addAddress(ADMIN_EMAIL);
        } else {
            error_log("ADMIN_EMAIL not defined");
            return false;
        }
        
        $mail->Subject = 'New Offer Received - TDS Marketplace';
        $mail->isHTML(true);
        $mail->Body = "
        <div style='font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto; padding: 20px;'>
            <h1 style='text-align: center;'>New Offer Received</h1>
            <table style='width: 100%; border-collapse: collapse; margin: 25px 0;'>
                <tr><td style='padding: 10px; border: 1px solid #ddd;'><strong>Product:</strong></td>
                    <td style='padding: 10px; border: 1px solid #ddd;'>$product_name</td></tr>
                <tr><td style='padding: 10px; border: 1px solid #ddd;'><strong>Variant:</strong></td>
                    <td style='padding: 10px; border: 1px solid #ddd;'>$variant_title</td></tr>
                <tr><td style='padding: 10px; border: 1px solid #ddd;'><strong>Offer Amount:</strong></td>
                    <td style='padding: 10px; border: 1px solid #ddd;'>₹" . number_format($offer_amount, 2) . "</td></tr>
                <tr><td style='padding: 10px; border: 1px solid #ddd;'><strong>Customer:</strong></td>
                    <td style='padding: 10px; border: 1px solid #ddd;'>$user_name ($user_email)</td></tr>
            </table>
            <p style='text-align: center;'>
                <a href='http://" . $_SERVER['HTTP_HOST'] . "/admin/offers.php' 
                   style='background: #000; color: #fff; padding: 12px 30px; text-decoration: none; border-radius: 4px;'>
                    Review in Admin Panel
                </a>
            </p>
        </div>";
        
        $mail->send();
        return true;
        
    } catch (Exception $e) {
        error_log("Email failed: " . $e->getMessage());
        return false;
    }
}

// ============================================
// ✅ SUBMIT NEW OFFER
// ============================================
if (!isset($_SESSION['user_id'])) {
    echo json_encode(['success' => false, 'message' => 'Please log in to make an offer']);
    exit;
}

if ($_SERVER['REQUEST_METHOD'] !== 'POST' || !isset($_POST['offer_amount'])) {
    // Not an offer submission, exit silently
    exit;
}

$userId = (int)$_SESSION['user_id'];
$userEmail = $_SESSION['user_email'] ?? '';
$userName = $_SESSION['user_name'] ?? '';
$userPhone = $_SESSION['user_phone'] ?? '';

$productId = isset($_POST['product_id']) ? (int)$_POST['product_id'] : (int)($_POST['pid'] ?? 0);
$variantId = isset($_POST['variant_id']) ? (int)$_POST['variant_id'] : null;
$variantTitle = trim($_POST['variant_title'] ?? '');
$variantAttributes = $_POST['variant_attributes'] ?? '{}';
$offerAmount = (float)($_POST['offer_amount'] ?? 0);

if ($productId <= 0) {
    echo json_encode(['success' => false, 'message' => 'Invalid product']);
    exit;
}

if ($offerAmount < 1) {
    echo json_encode(['success' => false, 'message' => 'Offer amount must be at least ₹1.00']);
    exit;
}

try {
    // Check for existing pending/accepted offers
    $checkSql = "SELECT offer_id, offer_amount, status 
                 FROM tbl_offers 
                 WHERE user_id = :user_id 
                 AND product_id = :product_id 
                 AND status IN ('pending', 'accepted')
                 LIMIT 1";
    
    $checkStmt = $pdo->prepare($checkSql);
    $checkStmt->execute([':user_id' => $userId, ':product_id' => $productId]);
    
    $existingOffer = $checkStmt->fetch();
    
    if ($existingOffer) {
        $statusMessage = $existingOffer['status'] === 'pending' 
            ? 'You already have a pending offer. Please wait for admin response.'
            : 'You have an active approved offer. Please wait for it to expire.';
        
        echo json_encode([
            'success' => false, 
            'message' => $statusMessage,
            'existing_offer' => true,
            'offer_id' => $existingOffer['offer_id'],
            'status' => $existingOffer['status']
        ]);
        exit;
    }
    
    // Insert new offer
    $insertSql = "INSERT INTO tbl_offers 
                  (product_id, variant_id, variant_title, variant_attributes, user_id, 
                   user_email, user_name, user_phone, offer_amount, created_at) 
                  VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, NOW())";
    
    $insertStmt = $pdo->prepare($insertSql);
    $insertStmt->execute([
        $productId, $variantId, $variantTitle, $variantAttributes,
        $userId, $userEmail, $userName, $userPhone, $offerAmount
    ]);
    
    $offerId = $pdo->lastInsertId();
    
    // Get product name
    $productStmt = $pdo->prepare("SELECT pname FROM products WHERE pid = ? LIMIT 1");
    $productStmt->execute([$productId]);
    $product = $productStmt->fetch();
    $productName = $product['pname'] ?? 'Unknown Product';
    
    // Send email
    $emailSent = sendAdminOfferNotification(
        $productName, $variantTitle, $userName, 
        $userEmail, $offerAmount, $productId, $offerId
    );
    
    echo json_encode([
        'success' => true, 
        'message' => 'Offer submitted successfully!',
        'offer_id' => $offerId,
        'email_sent' => $emailSent,
        'offer_data' => [
            'offer_id' => $offerId,
            'offer_amount' => $offerAmount,
            'product_id' => $productId,
            'status' => 'pending'
        ]
    ]);
    
} catch (PDOException $e) {
    error_log('Offer submission error: ' . $e->getMessage());
    echo json_encode(['success' => false, 'message' => 'Failed to submit offer']);
}
?>