package storage

import (
	"encoding/json"
	"fmt"
	"log"
	"network-topology-discovery/pkg/models"
	"os"
	"sync"
	"time"
)

// Storage 存储（使用JSON文件）
type Storage struct {
	mu       sync.RWMutex
	filePath string
	devices  map[string]models.Device
}

// NewStorage 创建存储实例（兼容旧版，使用默认文件）
func NewStorage(filePath string) (*Storage, error) {
	return NewStorageForTopology(filePath)
}

// NewStorageForTopology 为特定拓扑创建存储实例
func NewStorageForTopology(filePath string) (*Storage, error) {
	s := &Storage{
		filePath: filePath,
		devices:  make(map[string]models.Device),
	}

	// 从文件加载数据
	if err := s.load(); err != nil {
		if !os.IsNotExist(err) {
			return nil, fmt.Errorf("failed to load storage: %w", err)
		}
		// 文件不存在是正常的，创建新文件
		log.Printf("Creating new storage file: %s", filePath)
	}

	return s, nil
}

// SetFilePath 切换存储文件路径（用于切换拓扑）
func (s *Storage) SetFilePath(filePath string) error {
	s.mu.Lock()
	s.filePath = filePath
	s.devices = make(map[string]models.Device)
	s.mu.Unlock()

	// 重新加载数据
	if err := s.load(); err != nil {
		if !os.IsNotExist(err) {
			return fmt.Errorf("failed to load storage: %w", err)
		}
	}

	log.Printf("Storage switched to: %s", filePath)
	return nil
}

// load 从文件加载数据
func (s *Storage) load() error {
	data, err := os.ReadFile(s.filePath)
	if err != nil {
		return err
	}

	var devices []models.Device
	if err := json.Unmarshal(data, &devices); err != nil {
		return fmt.Errorf("failed to parse storage file: %w", err)
	}

	for _, dev := range devices {
		s.devices[dev.ID] = dev
	}

	log.Printf("Loaded %d devices from storage", len(devices))
	return nil
}

// save 保存数据到文件
func (s *Storage) save() error {
	devices := make([]models.Device, 0, len(s.devices))
	for _, dev := range s.devices {
		devices = append(devices, dev)
	}

	data, err := json.MarshalIndent(devices, "", "  ")
	if err != nil {
		return fmt.Errorf("failed to marshal devices: %w", err)
	}

	if err := os.WriteFile(s.filePath, data, 0644); err != nil {
		return fmt.Errorf("failed to write storage file: %w", err)
	}

	return nil
}

// SaveDevice 保存设备
func (s *Storage) SaveDevice(device *models.Device) error {
	s.mu.Lock()
	defer s.mu.Unlock()

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

	s.devices[device.ID] = *device

	// 保存到文件
	if err := s.save(); 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) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	device, exists := s.devices[id]
	if !exists {
		return nil, fmt.Errorf("device not found: %s", id)
	}

	return &device, nil
}

// GetAllDevices 获取所有设备
func (s *Storage) GetAllDevices() ([]models.Device, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	devices := make([]models.Device, 0, len(s.devices))
	for _, dev := range s.devices {
		devices = append(devices, dev)
	}

	return devices, nil
}

// DeleteDevice 删除设备
func (s *Storage) DeleteDevice(id string) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	delete(s.devices, id)

	// 保存到文件
	if err := s.save(); err != nil {
		return fmt.Errorf("failed to delete device: %w", err)
	}
	return nil
}

// Close 关闭存储（不需要操作，JSON文件不需要关闭）
func (s *Storage) Close() error {
	return nil
}