<?php
/**
 * WebGIS API - Utility Functions
 * Version: 1.0
 * Description: Common utility functions for API
 */

// Enable error logging
error_reporting(E_ALL);
ini_set('display_errors', 0);
ini_set('log_errors', 1);
ini_set('error_log', __DIR__ . '/logs/error.log');

// Create logs directory if not exists
if (!is_dir(__DIR__ . '/logs')) {
    mkdir(__DIR__ . '/logs', 0755, true);
}

// Set JSON content type
header('Content-Type: application/json; charset=utf-8');

/**
 * Validate input data based on type and rules
 */
function validateInput($data, $rules) {
    $errors = [];
    
    foreach ($rules as $field => $rule) {
        $value = $data[$field] ?? null;
        
        // Check required
        if (isset($rule['required']) && $rule['required'] && empty($value)) {
            $errors[$field] = "Field '{$field}' is required";
            continue;
        }
        
        // Skip validation if value is empty and not required
        if (empty($value) && (!isset($rule['required']) || !$rule['required'])) {
            continue;
        }
        
        // Check type
        if (isset($rule['type'])) {
            switch ($rule['type']) {
                case 'string':
                    if (!is_string($value)) {
                        $errors[$field] = "Field '{$field}' must be string";
                    }
                    break;
                case 'integer':
                    if (!is_numeric($value)) {
                        $errors[$field] = "Field '{$field}' must be numeric";
                    }
                    break;
                case 'double':
                    if (!is_numeric($value)) {
                        $errors[$field] = "Field '{$field}' must be numeric";
                    }
                    break;
                case 'enum':
                    if (isset($rule['values']) && !in_array($value, $rule['values'])) {
                        $errors[$field] = "Field '{$field}' has invalid value";
                    }
                    break;
            }
        }
        
        // Check length
        if (isset($rule['maxLength']) && strlen($value) > $rule['maxLength']) {
            $errors[$field] = "Field '{$field}' exceeds max length ({$rule['maxLength']})";
        }
        
        // Check min/max
        if (isset($rule['min']) && $value < $rule['min']) {
            $errors[$field] = "Field '{$field}' must be >= {$rule['min']}";
        }
        if (isset($rule['max']) && $value > $rule['max']) {
            $errors[$field] = "Field '{$field}' must be <= {$rule['max']}";
        }
    }
    
    return $errors;
}

/**
 * Sanitize input to prevent SQL injection
 */
function sanitizeInput($data, $conn) {
    if (is_array($data)) {
        foreach ($data as $key => $value) {
            $data[$key] = sanitizeInput($value, $conn);
        }
        return $data;
    }
    
    if (is_string($data)) {
        return $conn->real_escape_string(trim($data));
    }
    
    return $data;
}

/**
 * Send JSON response
 */
function sendResponse($success, $message, $data = null, $code = 200) {
    http_response_code($code);
    
    $response = [
        'success' => $success,
        'message' => $message,
        'timestamp' => date('Y-m-d H:i:s')
    ];
    
    if ($data !== null) {
        $response['data'] = $data;
    }
    
    echo json_encode($response);
    exit;
}

/**
 * Send error response
 */
function sendError($message, $code = 400, $errors = null) {
    http_response_code($code);
    
    $response = [
        'success' => false,
        'message' => $message,
        'timestamp' => date('Y-m-d H:i:s')
    ];
    
    if ($errors !== null) {
        $response['errors'] = $errors;
    }
    
    echo json_encode($response);
    exit;
}

/**
 * Log activity
 */
function logActivity($conn, $action, $details, $user = null) {
    $timestamp = date('Y-m-d H:i:s');
    $ip = $_SERVER['REMOTE_ADDR'] ?? 'unknown';
    $details_json = $conn->real_escape_string(json_encode($details));
    
    $sql = "INSERT INTO activity_log (action, details, user_name, ip_address, created_at) 
            VALUES ('$action', '$details_json', '" . ($user ?? 'system') . "', '$ip', '$timestamp')";
    
    $conn->query($sql);
}

/**
 * Get database connection
 */
function getConnection() {
    $conn = new mysqli("localhost", "root", "", "webgis_unified");
    
    if ($conn->connect_error) {
        sendError("Database connection failed: " . $conn->connect_error, 500);
    }
    
    $conn->set_charset("utf8mb4");
    return $conn;
}
?>