package network

import (
	"encoding/json"
	"os"
	"path/filepath"
	"sync"
)

var defaultMetadataPath = "/etc/proxmox-router/metadata.json"

// MetadataManager manages user annotations for interfaces.
type MetadataManager struct {
	mu       sync.RWMutex
	filePath string
	store    MetadataStore
}

func NewMetadataManager(customPath string) *MetadataManager {
	p := defaultMetadataPath
	if customPath != "" {
		p = customPath
	}
	mm := &MetadataManager{
		filePath: p,
		store: MetadataStore{
			Interfaces: make(map[string]InterfaceMetadata),
		},
	}
	mm.load()
	return mm
}

func (mm *MetadataManager) load() {
	mm.mu.Lock()
	defer mm.mu.Unlock()

	data, err := os.ReadFile(mm.filePath)
	if err != nil {
		return
	}
	_ = json.Unmarshal(data, &mm.store)
	if mm.store.Interfaces == nil {
		mm.store.Interfaces = make(map[string]InterfaceMetadata)
	}
}

func (mm *MetadataManager) save() error {
	dir := filepath.Dir(mm.filePath)
	if err := os.MkdirAll(dir, 0755); err != nil {
		return err
	}

	data, err := json.MarshalIndent(mm.store, "", "  ")
	if err != nil {
		return err
	}

	return os.WriteFile(mm.filePath, data, 0644)
}

func (mm *MetadataManager) Get(name string) InterfaceMetadata {
	mm.mu.RLock()
	defer mm.mu.RUnlock()
	return mm.store.Interfaces[name]
}

func (mm *MetadataManager) Set(name string, role, desc string) error {
	mm.mu.Lock()
	defer mm.mu.Unlock()

	meta := mm.store.Interfaces[name]
	meta.Role = role
	meta.Description = desc
	mm.store.Interfaces[name] = meta
	return mm.save()
}

func (mm *MetadataManager) AddIP(name, cidr string) error {
	mm.mu.Lock()
	defer mm.mu.Unlock()

	meta := mm.store.Interfaces[name]
	for _, ip := range meta.IPAddresses {
		if ip == cidr {
			return nil
		}
	}
	meta.IPAddresses = append(meta.IPAddresses, cidr)
	meta.AutoUp = true
	mm.store.Interfaces[name] = meta
	return mm.save()
}

func (mm *MetadataManager) RemoveIP(name, cidr string) error {
	mm.mu.Lock()
	defer mm.mu.Unlock()

	meta := mm.store.Interfaces[name]
	var updated []string
	for _, ip := range meta.IPAddresses {
		if ip != cidr {
			updated = append(updated, ip)
		}
	}
	meta.IPAddresses = updated
	mm.store.Interfaces[name] = meta
	return mm.save()
}

func (mm *MetadataManager) GetAllWithIPs() map[string][]string {
	mm.mu.RLock()
	defer mm.mu.RUnlock()

	res := make(map[string][]string)
	for name, meta := range mm.store.Interfaces {
		if len(meta.IPAddresses) > 0 {
			res[name] = append([]string(nil), meta.IPAddresses...)
		}
	}
	return res
}

func (mm *MetadataManager) Delete(name string) error {
	mm.mu.Lock()
	defer mm.mu.Unlock()

	delete(mm.store.Interfaces, name)
	return mm.save()
}

// Rename migrates interface metadata when an interface is renamed.
func (mm *MetadataManager) Rename(oldName, newName string) error {
	mm.mu.Lock()
	defer mm.mu.Unlock()

	if meta, exists := mm.store.Interfaces[oldName]; exists {
		delete(mm.store.Interfaces, oldName)
		mm.store.Interfaces[newName] = meta
		return mm.save()
	}
	return nil
}