<?php
// Start session if not already started
if (session_status() === PHP_SESSION_NONE) {
    session_start();
}

// Set proper content type
header('Content-Type: application/json');

// Basic authentication check
if (!isset($_SESSION['user_id'])) {
    http_response_code(403);
    echo json_encode(['success' => false, 'message' => 'Authentication required.']);
    exit;
}

// Check if image path is provided
if (!isset($_POST['path']) || empty($_POST['path'])) {
    http_response_code(400);
    echo json_encode(['success' => false, 'message' => 'Image path not provided.']);
    exit;
}

$imagePath = $_POST['path'];

// Sanitize the path: remove any query string to prevent issues with realpath()
$path_parts = parse_url($imagePath);
$imagePath = $path_parts['path'];

$baseDir = realpath(__DIR__ . '/../data/images/backgrounds');
$fullPath = realpath(__DIR__ . '/../' . $imagePath);

// Security check: ensure the file is within the backgrounds directory
if (!$fullPath || strpos($fullPath, $baseDir) !== 0 || !file_exists($fullPath)) {
    http_response_code(400);
    echo json_encode(['success' => false, 'message' => 'Invalid or non-existent image path.']);
    exit;
}

// Check if ImageMagick is available
if (!extension_loaded('imagick')) {
    http_response_code(500);
    echo json_encode(['success' => false, 'message' => 'ImageMagick extension not available.']);
    exit;
}

try {
    $imagick = new Imagick($fullPath);
    
    // Get image info
    $width = $imagick->getImageWidth();
    $height = $imagick->getImageHeight();
    $format = $imagick->getImageFormat();
    
    $maxWidth = 1920;
    $quality = 85;
    
    // Don't optimize if the image is already reasonably sized
    if ($width <= $maxWidth) {
        // Still, re-save with quality setting for JPEG
        if (strtolower($format) === 'jpeg' || strtolower($format) === 'jpg') {
            $imagick->setImageCompressionQuality($quality);
            $imagick->writeImage($fullPath);
            $imagick->destroy();
            echo json_encode(['success' => true, 'message' => 'Image quality adjusted, but no resize needed.']);
            exit;
        }
        // For other types, if no resize is needed, there's nothing to do.
        $imagick->destroy();
        echo json_encode(['success' => true, 'message' => 'Image is already optimized (width is within limit).']);
        exit;
    }
    
    // Resize the image
    $imagick->resizeImage($maxWidth, 0, Imagick::FILTER_LANCZOS, 1);
    
    // Set quality for JPEG
    if (strtolower($format) === 'jpeg' || strtolower($format) === 'jpg') {
        $imagick->setImageCompressionQuality($quality);
    }
    
    // Write the optimized image
    $imagick->writeImage($fullPath);
    $imagick->destroy();
    
    echo json_encode(['success' => true, 'message' => 'Image optimized successfully using ImageMagick.']);
    
} catch (ImagickException $e) {
    http_response_code(500);
    echo json_encode(['success' => false, 'message' => 'Error optimizing image: ' . $e->getMessage()]);
} catch (Exception $e) {
    http_response_code(500);
    echo json_encode(['success' => false, 'message' => 'Error: ' . $e->getMessage()]);
}