<?php
/**
 * FlatFileDB Class
 * 
 * Handles all flat-file JSON storage operations for the Pathvector admin dashboard
 */

class FlatFileDB {
    private string $filePath;
    private array $data;
    
    /**
     * Constructor
     * 
     * @param string $filePath Path to the JSON file
     */
    public function __construct(string $filePath) {
        $this->filePath = $filePath;
        $this->load();
    }
    
    /**
     * Load data from JSON file
     * 
     * @return void
     */
    private function load(): void {
        if (file_exists($this->filePath)) {
            $content = file_get_contents($this->filePath);
            $this->data = json_decode($content, true) ?? [];
        } else {
            $this->data = [];
            $this->save();
        }
    }
    
    /**
     * Save data to JSON file
     * 
     * @return bool
     */
    public function save(): bool {
        $dir = dirname($this->filePath);
        if (!is_dir($dir)) {
            mkdir($dir, 0755, true);
        }
        
        $json = json_encode($this->data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
        return file_put_contents($this->filePath, $json) !== false;
    }
    
    /**
     * Get all data
     * 
     * @return array
     */
    public function getAll(): array {
        return $this->data;
    }
    
    /**
     * Get data by key
     * 
     * @param string $key
     * @return mixed
     */
    public function get(string $key) {
        return $this->data[$key] ?? null;
    }
    
    /**
     * Set data by key
     * 
     * @param string $key
     * @param mixed $value
     * @return bool
     */
    public function set(string $key, $value): bool {
        $this->data[$key] = $value;
        return $this->save();
    }
    
    /**
     * Delete data by key
     * 
     * @param string $key
     * @return bool
     */
    public function delete(string $key): bool {
        if (isset($this->data[$key])) {
            unset($this->data[$key]);
            return $this->save();
        }
        return false;
    }
    
    /**
     * Check if key exists
     * 
     * @param string $key
     * @return bool
     */
    public function exists(string $key): bool {
        return isset($this->data[$key]);
    }
    
    /**
     * Get all keys
     * 
     * @return array
     */
    public function keys(): array {
        return array_keys($this->data);
    }
    
    /**
     * Count all entries
     * 
     * @return int
     */
    public function count(): int {
        return count($this->data);
    }
    
    /**
     * Clear all data
     * 
     * @return bool
     */
    public function clear(): bool {
        $this->data = [];
        return $this->save();
    }
    
    /**
     * Search data by callback function
     * 
     * @param callable $callback
     * @return array
     */
    public function search(callable $callback): array {
        return array_filter($this->data, $callback, ARRAY_FILTER_USE_BOTH);
    }
    
    /**
     * Update data by key with callback
     * 
     * @param string $key
     * @param callable $callback
     * @return bool
     */
    public function update(string $key, callable $callback): bool {
        if (isset($this->data[$key])) {
            $this->data[$key] = $callback($this->data[$key]);
            return $this->save();
        }
        return false;
    }
    
    /**
     * Get file path
     * 
     * @return string
     */
    public function getFilePath(): string {
        return $this->filePath;
    }
    
    /**
     * Reload data from file
     * 
     * @return void
     */
    public function reload(): void {
        $this->load();
    }
    
    /**
     * Backup current data
     * 
     * @param string $backupDir
     * @return string|false Returns backup file path on success, false on failure
     */
    public function backup(string $backupDir): string|false {
        if (!is_dir($backupDir)) {
            mkdir($backupDir, 0755, true);
        }
        
        $timestamp = date('Y-m-d_H-i-s');
        $filename = basename($this->filePath, '.json');
        $backupPath = $backupDir . '/' . $filename . '_' . $timestamp . '.json';
        
        $json = json_encode($this->data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
        return file_put_contents($backupPath, $json) !== false ? $backupPath : false;
    }
    
    /**
     * Restore data from backup file
     * 
     * @param string $backupPath
     * @return bool
     */
    public function restore(string $backupPath): bool {
        if (!file_exists($backupPath)) {
            return false;
        }
        
        $content = file_get_contents($backupPath);
        $data = json_decode($content, true);
        
        if ($data === null) {
            return false;
        }
        
        $this->data = $data;
        return $this->save();
    }
}