package com.ruoyi.security.service.impl;

import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;

import javax.crypto.SecretKey;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

import com.ruoyi.security.service.EncryptionService;
import com.ruoyi.security.service.KeyManagementService;

/**
 * 密钥管理服务实现
 * 
 * @author ruoyi
 */
@Service
public class KeyManagementServiceImpl implements KeyManagementService {
    
    private static final Logger log = LoggerFactory.getLogger(KeyManagementServiceImpl.class);
    
    @Autowired
    private EncryptionService encryptionService;
    
    @Value("${security.hsm.enabled:false}")
    private boolean hsmEnabled;
    
    @Value("${security.hsm.endpoint:}")
    private String hsmEndpoint;
    
    // 密钥存储
    private final ConcurrentHashMap<String, KeyInfo> keyStore = new ConcurrentHashMap<>();
    
    /**
     * 密钥信息类
     */
    private static class KeyInfo {
        private final SecretKey key;
        private final String keyType;
        private final LocalDateTime createdAt;
        private String status;
        private LocalDateTime lastUsed;
        
        public KeyInfo(SecretKey key, String keyType) {
            this.key = key;
            this.keyType = keyType;
            this.createdAt = LocalDateTime.now();
            this.status = "ACTIVE";
            this.lastUsed = LocalDateTime.now();
        }
        
        // Getters and setters
        public SecretKey getKey() { return key; }
        public String getKeyType() { return keyType; }
        public LocalDateTime getCreatedAt() { return createdAt; }
        public String getStatus() { return status; }
        public void setStatus(String status) { this.status = status; }
        public LocalDateTime getLastUsed() { return lastUsed; }
        public void setLastUsed(LocalDateTime lastUsed) { this.lastUsed = lastUsed; }
    }
    
    @Override
    public String createKey(String keyType) {
        try {
            SecretKey key = encryptionService.generateKey();
            String keyId = generateKeyId(keyType);
            
            KeyInfo keyInfo = new KeyInfo(key, keyType);
            keyStore.put(keyId, keyInfo);
            
            log.info("Created new key: {} of type: {}", keyId, keyType);
            
            // 如果启用HSM，备份到HSM
            if (hsmEnabled) {
                backupToHsm(keyId);
            }
            
            return keyId;
        } catch (Exception e) {
            log.error("Failed to create key of type: {}", keyType, e);
            throw new RuntimeException("Key creation failed", e);
        }
    }
    
    @Override
    public SecretKey getKey(String keyId) {
        KeyInfo keyInfo = keyStore.get(keyId);
        if (keyInfo == null) {
            log.warn("Key not found: {}", keyId);
            return null;
        }
        
        if (!"ACTIVE".equals(keyInfo.getStatus())) {
            log.warn("Key is not active: {}, status: {}", keyId, keyInfo.getStatus());
            return null;
        }
        
        keyInfo.setLastUsed(LocalDateTime.now());
        return keyInfo.getKey();
    }
    
    @Override
    public boolean deleteKey(String keyId) {
        try {
            KeyInfo keyInfo = keyStore.remove(keyId);
            if (keyInfo != null) {
                log.info("Deleted key: {}", keyId);
                return true;
            } else {
                log.warn("Key not found for deletion: {}", keyId);
                return false;
            }
        } catch (Exception e) {
            log.error("Failed to delete key: {}", keyId, e);
            return false;
        }
    }
    
    @Override
    public List<String> listKeys() {
        return new ArrayList<>(keyStore.keySet());
    }
    
    @Override
    public boolean enableKey(String keyId) {
        KeyInfo keyInfo = keyStore.get(keyId);
        if (keyInfo != null) {
            keyInfo.setStatus("ACTIVE");
            log.info("Enabled key: {}", keyId);
            return true;
        }
        return false;
    }
    
    @Override
    public boolean disableKey(String keyId) {
        KeyInfo keyInfo = keyStore.get(keyId);
        if (keyInfo != null) {
            keyInfo.setStatus("DISABLED");
            log.info("Disabled key: {}", keyId);
            return true;
        }
        return false;
    }
    
    @Override
    public String getKeyStatus(String keyId) {
        KeyInfo keyInfo = keyStore.get(keyId);
        return keyInfo != null ? keyInfo.getStatus() : "NOT_FOUND";
    }
    
    /**
     * 获取密钥详细信息
     */
    public String getKeyInfo(String keyId) {
        KeyInfo keyInfo = keyStore.get(keyId);
        if (keyInfo == null) {
            return "Key not found: " + keyId;
        }
        
        return String.format("Key ID: %s, Type: %s, Status: %s, Created: %s, Last Used: %s",
            keyId, keyInfo.getKeyType(), keyInfo.getStatus(), 
            keyInfo.getCreatedAt(), keyInfo.getLastUsed());
    }
    
    @Override
    public String rotateKey(String oldKeyId) {
        try {
            KeyInfo oldKeyInfo = keyStore.get(oldKeyId);
            if (oldKeyInfo == null) {
                throw new IllegalArgumentException("Old key not found: " + oldKeyId);
            }
            
            // 创建新密钥
            String newKeyId = createKey(oldKeyInfo.getKeyType());
            
            // 禁用旧密钥
            disableKey(oldKeyId);
            
            log.info("Rotated key from {} to {}", oldKeyId, newKeyId);
            return newKeyId;
        } catch (IllegalArgumentException e) {
            log.error("Failed to rotate key: {}", oldKeyId, e);
            throw new RuntimeException("Key rotation failed", e);
        }
    }
    
    @Override
    public boolean backupToHsm(String keyId) {
        if (!hsmEnabled) {
            log.debug("HSM not enabled, skipping backup for key: {}", keyId);
            return true;
        }
        
        try {
            // HSM集成逻辑 - 这里是模拟实现
            // 实际实现需要根据具体的HSM厂商API进行集成
            log.info("Backing up key to HSM: {}", keyId);
            
            // 模拟HSM备份操作
            Thread.sleep(100); // 模拟网络延迟
            
            log.info("Successfully backed up key to HSM: {}", keyId);
            return true;
        } catch (InterruptedException e) {
            log.error("Failed to backup key to HSM: {}", keyId, e);
            return false;
        }
    }
    
    @Override
    public boolean restoreFromHsm(String keyId) {
        if (!hsmEnabled) {
            log.debug("HSM not enabled, cannot restore key: {}", keyId);
            return false;
        }
        
        try {
            // HSM恢复逻辑 - 这里是模拟实现
            log.info("Restoring key from HSM: {}", keyId);
            
            // 模拟HSM恢复操作
            Thread.sleep(100); // 模拟网络延迟
            
            log.info("Successfully restored key from HSM: {}", keyId);
            return true;
        } catch (InterruptedException e) {
            log.error("Failed to restore key from HSM: {}", keyId, e);
            return false;
        }
    }
    
    /**
     * 生成密钥ID
     */
    private String generateKeyId(String keyType) {
        return String.format("%s_%d_%d", 
            keyType.toUpperCase(), 
            System.currentTimeMillis(), 
            System.nanoTime() % 1000000);
    }
}