<?php
$rootPath = dirname(dirname(__DIR__));
require_once($rootPath . '/src/config/env.php');
require_once($rootPath . '/src/config/session.php');
require_once($rootPath . '/src/config/connection.php');
require_once($rootPath . '/src/config/functions.php');

if (!isset($_SESSION['user_id']) || $_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(403);
    exit('Forbidden');
}

// Validate CSRF token
if (!isset($_POST['csrf_token']) || !validateCSRFToken($_POST['csrf_token'])) {
    http_response_code(400);
    exit('Invalid request');
}

$album_id = intval($_POST['album_id'] ?? 0);
$title = trim($_POST['title'] ?? '');
$description = trim($_POST['description'] ?? '');
$user_id = $_SESSION['user_id'];

if (!$album_id) {
    $conn->close();
    http_response_code(400);
    echo json_encode(['error' => 'Album ID is required']);
    exit;
}

// Verify ownership
$ownerCheck = $conn->prepare("SELECT user_id FROM photo_albums WHERE album_id = ?");
$ownerCheck->bind_param("i", $album_id);
$ownerCheck->execute();
$ownerResult = $ownerCheck->get_result();

if ($ownerResult->num_rows === 0) {
    $conn->close();
    http_response_code(404);
    echo json_encode(['error' => 'Album not found']);
    exit;
}

$owner = $ownerResult->fetch_assoc();
if ($owner['user_id'] !== $user_id) {
    $conn->close();
    http_response_code(403);
    echo json_encode(['error' => 'You do not have permission to edit this album']);
    exit;
}
$ownerCheck->close();

// Validate inputs
if (empty($title) || !validateName($title)) {
    $conn->close();
    http_response_code(400);
    echo json_encode(['error' => 'Album title is required and must be valid']);
    exit;
}

if (!empty($description) && strlen($description) > 500) {
    $conn->close();
    http_response_code(400);
    echo json_encode(['error' => 'Description must be 500 characters or less']);
    exit;
}

try {
    // Start transaction
    $conn->begin_transaction();

    // Update album
    $updateStmt = $conn->prepare("UPDATE photo_albums SET title = ?, description = ?, updated_at = NOW() WHERE album_id = ?");
    $updateStmt->bind_param("ssi", $title, $description, $album_id);
    $updateStmt->execute();
    $updateStmt->close();

    // Handle cover image upload if provided
    if (isset($_FILES['cover_image']) && $_FILES['cover_image']['error'] === UPLOAD_ERR_OK) {
        $fileName = $_FILES['cover_image']['name'];
        $fileTmpName = $_FILES['cover_image']['tmp_name'];
        $fileSize = $_FILES['cover_image']['size'];
        
        // Validate file extension
        $ext = strtolower(pathinfo($fileName, PATHINFO_EXTENSION));
        $allowedExtensions = ['jpg', 'jpeg', 'png', 'gif', 'webp'];
        
        if (!in_array($ext, $allowedExtensions)) {
            throw new Exception('Invalid cover image file type. Allowed: jpg, jpeg, png, gif, webp');
        }

        if ($fileSize > 5 * 1024 * 1024) {
            throw new Exception('Cover image file too large (max 5MB)');
        }

        $albumDir = $rootPath . '/assets/uploads/gallery/' . $album_id;
        
        // Create directory if it doesn't exist (match working pattern)
        if (!file_exists($albumDir)) {
            mkdir($albumDir, 0777, true);
        }

        // Delete old cover if it exists
        $oldCoverStmt = $conn->prepare("SELECT cover_image FROM photo_albums WHERE album_id = ?");
        $oldCoverStmt->bind_param("i", $album_id);
        $oldCoverStmt->execute();
        $oldCoverResult = $oldCoverStmt->get_result();
        if ($oldCoverResult->num_rows > 0) {
            $oldCover = $oldCoverResult->fetch_assoc();
            if ($oldCover['cover_image']) {
                $oldCoverPath = $rootPath . $oldCover['cover_image'];
                if (file_exists($oldCoverPath)) {
                    @unlink($oldCoverPath);
                }
            }
        }
        $oldCoverStmt->close();

        // Generate unique filename
        $newFileName = 'cover_' . uniqid() . '.' . $ext;
        $filePath = $albumDir . '/' . $newFileName;
        $coverImagePath = '/assets/uploads/gallery/' . $album_id . '/' . $newFileName;

        if (!move_uploaded_file($fileTmpName, $filePath)) {
            throw new Exception('Failed to upload cover image');
        }

        // Update cover image in album record
        $updateCover = $conn->prepare("UPDATE photo_albums SET cover_image = ? WHERE album_id = ?");
        $updateCover->bind_param("si", $coverImagePath, $album_id);
        $updateCover->execute();
        $updateCover->close();
    }

    // Handle photo uploads if any
    if (isset($_FILES['photos']) && $_FILES['photos']['error'][0] === UPLOAD_ERR_OK) {
        $maxSize = 5 * 1024 * 1024; // 5MB
        $albumDir = $rootPath . '/assets/uploads/gallery/' . $album_id;
        
        // Create directory if it doesn't exist (match working pattern)
        if (!file_exists($albumDir)) {
            mkdir($albumDir, 0777, true);
        }
        
        // Get current max display order
        $orderStmt = $conn->prepare("SELECT MAX(display_order) as max_order FROM photos WHERE album_id = ?");
        $orderStmt->bind_param("i", $album_id);
        $orderStmt->execute();
        $orderResult = $orderStmt->get_result();
        $orderRow = $orderResult->fetch_assoc();
        $displayOrder = ($orderRow['max_order'] ?? 0) + 1;
        $orderStmt->close();

        for ($i = 0; $i < count($_FILES['photos']['name']); $i++) {
            if ($_FILES['photos']['error'][$i] !== UPLOAD_ERR_OK) {
                continue;
            }

            $fileName = $_FILES['photos']['name'][$i];
            $fileTmpName = $_FILES['photos']['tmp_name'][$i];
            $fileSize = $_FILES['photos']['size'][$i];
            
            // Validate file extension
            $ext = strtolower(pathinfo($fileName, PATHINFO_EXTENSION));
            $allowedExtensions = ['jpg', 'jpeg', 'png', 'gif', 'webp'];
            
            if (!in_array($ext, $allowedExtensions)) {
                throw new Exception('Invalid file type: ' . $fileName . '. Allowed: jpg, jpeg, png, gif, webp');
            }

            if ($fileSize > $maxSize) {
                throw new Exception('File too large: ' . $fileName . ' (max 5MB)');
            }

            // Generate unique filename
            $ext = pathinfo($fileName, PATHINFO_EXTENSION);
            $newFileName = uniqid('photo_') . '.' . $ext;
            $filePath = $albumDir . '/' . $newFileName;
            $relativePath = '/assets/uploads/gallery/' . $album_id . '/' . $newFileName;

            if (!move_uploaded_file($fileTmpName, $filePath)) {
                throw new Exception('Failed to upload: ' . $fileName);
            }

            // Insert photo record
            $caption = $fileName; // Default caption is filename
            $photoStmt = $conn->prepare("INSERT INTO photos (album_id, file_path, caption, display_order, created_at) VALUES (?, ?, ?, ?, NOW())");
            $photoStmt->bind_param("issi", $album_id, $relativePath, $caption, $displayOrder);
            $photoStmt->execute();
            $photoStmt->close();

            $displayOrder++;
        }
    }

    // Commit transaction
    $conn->commit();
    $conn->close();

    // Redirect back to album view
    header('Location: view_album?id=' . $album_id);
    exit;

} catch (Exception $e) {
    // Rollback on error
    $conn->rollback();
    $conn->close();

    http_response_code(400);
    echo json_encode(['error' => $e->getMessage()]);
    exit;
}
?>