package com.cube.storage;

import java.io.IOException;
import java.util.*;

/**
 * Storage engine interface for Cube database.
 * Pure Java implementation with no native dependencies.
 */
public interface StorageEngine {
    
    void put(String key, byte[] value) throws IOException;
    
    byte[] get(String key) throws IOException;
    
    boolean delete(String key) throws IOException;
    
    Iterator<String> scan(String prefix) throws IOException;
    
    Iterator<Map.Entry<String, byte[]>> scanEntries(String prefix) throws IOException;
    
    void flush() throws IOException;
    
    void compact() throws IOException;
    
    StorageStats getStats();
    
    void close() throws IOException;
    
    class StorageStats {
        private final long totalKeys;
        private final long totalSize;
        private final long memtableSize;
        private final long sstableCount;
        
        public StorageStats(long totalKeys, long totalSize, long memtableSize, long sstableCount) {
            this.totalKeys = totalKeys;
            this.totalSize = totalSize;
            this.memtableSize = memtableSize;
            this.sstableCount = sstableCount;
        }
        
        public long getTotalKeys() { return totalKeys; }
        public long getTotalSize() { return totalSize; }
        public long getMemtableSize() { return memtableSize; }
        public long getSstableCount() { return sstableCount; }
        
        @Override
        public String toString() {
            return "StorageStats{" +
                   "keys=" + totalKeys +
                   ", size=" + totalSize +
                   ", memtable=" + memtableSize +
                   ", sstables=" + sstableCount +
                   '}';
        }
    }
}