package storage

import (
	"database/sql"
	"encoding/json"
	"fmt"
	"log"
	"network-topology-discovery/pkg/models"
	"time"

	_ "github.com/mattn/go-sqlite3"
)

// Storage 数据库存储
type Storage struct {
	db *sql.DB
}

// NewStorage 创建存储实例
func NewStorage(dbPath string) (*Storage, error) {
	db, err := sql.Open("sqlite3", dbPath)
	if err != nil {
		return nil, fmt.Errorf("failed to open database: %w", err)
	}

	// 创建表
	if err := createTables(db); err != nil {
		return nil, fmt.Errorf("failed to create tables: %w", err)
	}

	return &Storage{db: db}, nil
}

// createTables 创建数据表
func createTables(db *sql.DB) error {
	query := `
	CREATE TABLE IF NOT EXISTS devices (
		id TEXT PRIMARY KEY,
		ip TEXT NOT NULL UNIQUE,
		type TEXT NOT NULL,
		hostname TEXT,
		os_version TEXT,
		uptime TEXT,
		interfaces TEXT,
		neighbors TEXT,
		last_scanned DATETIME,
		scan_status TEXT,
		error_message TEXT,
		created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
		updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
	);
	
	CREATE INDEX IF NOT EXISTS idx_devices_ip ON devices(ip);
	CREATE INDEX IF NOT EXISTS idx_devices_type ON devices(type);
	`
	
	_, err := db.Exec(query)
	return err
}

// SaveDevice 保存设备
func (s *Storage) SaveDevice(device *models.Device) error {
	// 序列化接口和邻居数据
	interfacesJSON, err := json.Marshal(device.Interfaces)
	if err != nil {
		return fmt.Errorf("failed to marshal interfaces: %w", err)
	}

	neighborsJSON, err := json.Marshal(device.Neighbors)
	if err != nil {
		return fmt.Errorf("failed to marshal neighbors: %w", err)
	}

	// 设置ID和扫描时间
	if device.ID == "" {
		device.ID = device.IP
	}
	device.LastScanned = time.Now()

	query := `
	INSERT OR REPLACE INTO devices 
	(id, ip, type, hostname, os_version, uptime, interfaces, neighbors, 
	 last_scanned, scan_status, error_message, updated_at)
	VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
	`

	_, err = s.db.Exec(query,
		device.ID,
		device.IP,
		string(device.Type),
		device.Hostname,
		device.OSVersion,
		device.Uptime,
		string(interfacesJSON),
		string(neighborsJSON),
		device.LastScanned,
		device.ScanStatus,
		device.ErrorMessage,
		time.Now(),
	)

	if err != nil {
		return fmt.Errorf("failed to save device: %w", err)
	}

	log.Printf("Device saved: %s (%s)", device.IP, device.Hostname)
	return nil
}

// GetDevice 获取设备
func (s *Storage) GetDevice(id string) (*models.Device, error) {
	query := `
	SELECT id, ip, type, hostname, os_version, uptime, interfaces, neighbors,
	       last_scanned, scan_status, error_message
	FROM devices WHERE id = ?
	`

	row := s.db.QueryRow(query, id)
	
	var device models.Device
	var typeStr string
	var interfacesJSON, neighborsJSON string
	var lastScanned sql.NullTime

	err := row.Scan(
		&device.ID, &device.IP, &typeStr, &device.Hostname,
		&device.OSVersion, &device.Uptime, &interfacesJSON, &neighborsJSON,
		&lastScanned, &device.ScanStatus, &device.ErrorMessage,
	)
	
	if err != nil {
		return nil, fmt.Errorf("failed to get device: %w", err)
	}

	device.Type = models.DeviceType(typeStr)
	
	if lastScanned.Valid {
		device.LastScanned = lastScanned.Time
	}

	// 反序列化接口
	if interfacesJSON != "" {
		if err := json.Unmarshal([]byte(interfacesJSON), &device.Interfaces); err != nil {
			log.Printf("Warning: failed to unmarshal interfaces for %s: %v", device.IP, err)
		}
	}

	// 反序列化邻居
	if neighborsJSON != "" {
		if err := json.Unmarshal([]byte(neighborsJSON), &device.Neighbors); err != nil {
			log.Printf("Warning: failed to unmarshal neighbors for %s: %v", device.IP, err)
		}
	}

	return &device, nil
}

// GetAllDevices 获取所有设备
func (s *Storage) GetAllDevices() ([]models.Device, error) {
	query := `
	SELECT id, ip, type, hostname, os_version, uptime, interfaces, neighbors,
	       last_scanned, scan_status, error_message
	FROM devices ORDER BY created_at
	`

	rows, err := s.db.Query(query)
	if err != nil {
		return nil, fmt.Errorf("failed to query devices: %w", err)
	}
	defer rows.Close()

	var devices []models.Device

	for rows.Next() {
		var device models.Device
		var typeStr string
		var interfacesJSON, neighborsJSON string
		var lastScanned sql.NullTime

		err := rows.Scan(
			&device.ID, &device.IP, &typeStr, &device.Hostname,
			&device.OSVersion, &device.Uptime, &interfacesJSON, &neighborsJSON,
			&lastScanned, &device.ScanStatus, &device.ErrorMessage,
		)
		
		if err != nil {
			log.Printf("Warning: failed to scan device row: %v", err)
			continue
		}

		device.Type = models.DeviceType(typeStr)
		
		if lastScanned.Valid {
			device.LastScanned = lastScanned.Time
		}

		// 反序列化接口
		if interfacesJSON != "" {
			if err := json.Unmarshal([]byte(interfacesJSON), &device.Interfaces); err != nil {
				log.Printf("Warning: failed to unmarshal interfaces for %s: %v", device.IP, err)
			}
		}

		// 反序列化邻居
		if neighborsJSON != "" {
			if err := json.Unmarshal([]byte(neighborsJSON), &device.Neighbors); err != nil {
				log.Printf("Warning: failed to unmarshal neighbors for %s: %v", device.IP, err)
			}
		}

		devices = append(devices, device)
	}

	return devices, nil
}

// DeleteDevice 删除设备
func (s *Storage) DeleteDevice(id string) error {
	_, err := s.db.Exec("DELETE FROM devices WHERE id = ?", id)
	if err != nil {
		return fmt.Errorf("failed to delete device: %w", err)
	}
	return nil
}

// Close 关闭数据库连接
func (s *Storage) Close() error {
	if s.db != nil {
		return s.db.Close()
	}
	return nil
}