<?php
/**
 * Logger Class
 * 
 * Handles audit logging for the Pathvector admin dashboard
 */

require_once __DIR__ . '/FlatFileDB.php';

class Logger {
    private FlatFileDB $db;
    private int $maxEntries;
    private array $validLevels = ['info', 'warning', 'error', 'success'];
    
    /**
     * Constructor
     * 
     * @param string $logFile Path to the log file
     * @param int $maxEntries Maximum number of log entries to keep
     */
    public function __construct(string $logFile, int $maxEntries = 1000) {
        $this->db = new FlatFileDB($logFile);
        $this->maxEntries = $maxEntries;
        
        // Initialize logs array if not exists
        if (!$this->db->exists('logs')) {
            $this->db->set('logs', []);
        }
    }
    
    /**
     * Add a log entry
     * 
     * @param string $level Log level (info, warning, error, success)
     * @param string $action Action performed
     * @param string $message Log message
     * @param string|null $user User who performed the action
     * @param array $context Additional context data
     * @return bool
     */
    public function log(string $level, string $action, string $message, ?string $user = null, array $context = []): bool {
        if (!in_array($level, $this->validLevels)) {
            $level = 'info';
        }
        
        $logs = $this->db->get('logs') ?? [];
        
        $entry = [
            'id' => uniqid('log_'),
            'timestamp' => date('c'),
            'level' => $level,
            'action' => $action,
            'message' => $message,
            'user' => $user ?? ($_SESSION['user']['username'] ?? 'system'),
            'ip' => $_SERVER['REMOTE_ADDR'] ?? 'unknown',
            'user_agent' => $_SERVER['HTTP_USER_AGENT'] ?? 'unknown',
            'context' => $context,
        ];
        
        array_unshift($logs, $entry);
        
        // Trim logs to max entries
        if (count($logs) > $this->maxEntries) {
            $logs = array_slice($logs, 0, $this->maxEntries);
        }
        
        return $this->db->set('logs', $logs);
    }
    
    /**
     * Log info level message
     * 
     * @param string $action
     * @param string $message
     * @param array $context
     * @return bool
     */
    public function info(string $action, string $message, array $context = []): bool {
        return $this->log('info', $action, $message, null, $context);
    }
    
    /**
     * Log warning level message
     * 
     * @param string $action
     * @param string $message
     * @param array $context
     * @return bool
     */
    public function warning(string $action, string $message, array $context = []): bool {
        return $this->log('warning', $action, $message, null, $context);
    }
    
    /**
     * Log error level message
     * 
     * @param string $action
     * @param string $message
     * @param array $context
     * @return bool
     */
    public function error(string $action, string $message, array $context = []): bool {
        return $this->log('error', $action, $message, null, $context);
    }
    
    /**
     * Log success level message
     * 
     * @param string $action
     * @param string $message
     * @param array $context
     * @return bool
     */
    public function success(string $action, string $message, array $context = []): bool {
        return $this->log('success', $action, $message, null, $context);
    }
    
    /**
     * Get all logs
     * 
     * @param int|null $limit
     * @param int $offset
     * @return array
     */
    public function getLogs(?int $limit = null, int $offset = 0): array {
        $logs = $this->db->get('logs') ?? [];
        
        if ($limit !== null) {
            return array_slice($logs, $offset, $limit);
        }
        
        return $logs;
    }
    
    /**
     * Get logs by level
     * 
     * @param string $level
     * @param int|null $limit
     * @return array
     */
    public function getByLevel(string $level, ?int $limit = null): array {
        $logs = $this->db->get('logs') ?? [];
        $filtered = array_filter($logs, fn($log) => $log['level'] === $level);
        
        if ($limit !== null) {
            return array_slice($filtered, 0, $limit);
        }
        
        return array_values($filtered);
    }
    
    /**
     * Get logs by user
     * 
     * @param string $user
     * @param int|null $limit
     * @return array
     */
    public function getByUser(string $user, ?int $limit = null): array {
        $logs = $this->db->get('logs') ?? [];
        $filtered = array_filter($logs, fn($log) => $log['user'] === $user);
        
        if ($limit !== null) {
            return array_slice($filtered, 0, $limit);
        }
        
        return array_values($filtered);
    }
    
    /**
     * Get logs by action
     * 
     * @param string $action
     * @param int|null $limit
     * @return array
     */
    public function getByAction(string $action, ?int $limit = null): array {
        $logs = $this->db->get('logs') ?? [];
        $filtered = array_filter($logs, fn($log) => strpos($log['action'], $action) !== false);
        
        if ($limit !== null) {
            return array_slice($filtered, 0, $limit);
        }
        
        return array_values($filtered);
    }
    
    /**
     * Get logs by date range
     * 
     * @param string $startDate
     * @param string $endDate
     * @return array
     */
    public function getByDateRange(string $startDate, string $endDate): array {
        $logs = $this->db->get('logs') ?? [];
        $start = strtotime($startDate);
        $end = strtotime($endDate);
        
        return array_values(array_filter($logs, function($log) use ($start, $end) {
            $logTime = strtotime($log['timestamp']);
            return $logTime >= $start && $logTime <= $end;
        }));
    }
    
    /**
     * Search logs
     * 
     * @param string $query
     * @param int|null $limit
     * @return array
     */
    public function search(string $query, ?int $limit = null): array {
        $logs = $this->db->get('logs') ?? [];
        $query = strtolower($query);
        
        $filtered = array_filter($logs, function($log) use ($query) {
            return strpos(strtolower($log['message']), $query) !== false ||
                   strpos(strtolower($log['action']), $query) !== false ||
                   strpos(strtolower($log['user']), $query) !== false;
        });
        
        if ($limit !== null) {
            return array_slice($filtered, 0, $limit);
        }
        
        return array_values($filtered);
    }
    
    /**
     * Get total log count
     * 
     * @return int
     */
    public function count(): int {
        $logs = $this->db->get('logs') ?? [];
        return count($logs);
    }
    
    /**
     * Clear all logs
     * 
     * @return bool
     */
    public function clear(): bool {
        return $this->db->set('logs', []);
    }
    
    /**
     * Export logs to JSON
     * 
     * @return string
     */
    public function exportJson(): string {
        $logs = $this->db->get('logs') ?? [];
        return json_encode($logs, JSON_PRETTY_PRINT);
    }
    
    /**
     * Export logs to CSV
     * 
     * @return string
     */
    public function exportCsv(): string {
        $logs = $this->db->get('logs') ?? [];
        
        $output = "ID,Timestamp,Level,Action,Message,User,IP\n";
        
        foreach ($logs as $log) {
            $output .= sprintf(
                '"%s","%s","%s","%s","%s","%s","%s"' . "\n",
                $log['id'],
                $log['timestamp'],
                $log['level'],
                str_replace('"', '""', $log['action']),
                str_replace('"', '""', $log['message']),
                $log['user'],
                $log['ip']
            );
        }
        
        return $output;
    }
}