1 files changed, 217 insertions, 0 deletions
diff --git a/addressbook/addressbook.go b/addressbook/addressbook.go
new file mode 100644
index 0000000..e6876c0
--- /dev/null
+++ b/addressbook/addressbook.go
@@ -0,0 +1,217 @@
+// Package addressbook manages contacts and their public keys
+package addressbook
+
+import (
+	"crypto/ed25519"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"os"
+	"sync"
+	"time"
+)
+
+// Contact represents a contact in the address book
+type Contact struct {
+	Name         string            `json:"name"`
+	PublicKey    string            `json:"public_key"`    // hex-encoded Ed25519 public key
+	OnionAddress string            `json:"onion_address"` // Tor hidden service address
+	Fingerprint  string            `json:"fingerprint"`   // Short fingerprint for verification
+	AddedAt      time.Time         `json:"added_at"`
+	LastSeen     time.Time         `json:"last_seen"`
+	Verified     bool              `json:"verified"` // Manual verification flag
+	Notes        string            `json:"notes"`
+	Metadata     map[string]string `json:"metadata,omitempty"`
+}
+
+// AddressBook manages a collection of contacts
+type AddressBook struct {
+	contacts map[string]*Contact // key = public key hex
+	mu       sync.RWMutex
+	path     string
+}
+
+// NewAddressBook creates a new empty address book
+func NewAddressBook() *AddressBook {
+	return &AddressBook{
+		contacts: make(map[string]*Contact),
+	}
+}
+
+// LoadAddressBook loads an address book from disk
+func LoadAddressBook(path string) (*AddressBook, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read address book: %w", err)
+	}
+
+	var contacts []*Contact
+	if err := json.Unmarshal(data, &contacts); err != nil {
+		return nil, fmt.Errorf("failed to parse address book: %w", err)
+	}
+
+	ab := &AddressBook{
+		contacts: make(map[string]*Contact),
+		path:     path,
+	}
+
+	for _, contact := range contacts {
+		ab.contacts[contact.PublicKey] = contact
+	}
+
+	return ab, nil
+}
+
+// Save saves the address book to disk
+func (ab *AddressBook) Save(path string) error {
+	ab.mu.RLock()
+	defer ab.mu.RUnlock()
+
+	// Convert map to slice
+	contacts := make([]*Contact, 0, len(ab.contacts))
+	for _, contact := range ab.contacts {
+		contacts = append(contacts, contact)
+	}
+
+	// Marshal to JSON
+	data, err := json.MarshalIndent(contacts, "", "  ")
+	if err != nil {
+		return fmt.Errorf("failed to marshal address book: %w", err)
+	}
+
+	// Write to file
+	if err := os.WriteFile(path, data, 0600); err != nil {
+		return fmt.Errorf("failed to write address book: %w", err)
+	}
+
+	ab.path = path
+	return nil
+}
+
+// AddContact adds a new contact to the address book
+func (ab *AddressBook) AddContact(contact *Contact) error {
+	ab.mu.Lock()
+	defer ab.mu.Unlock()
+
+	// Validate public key
+	pubKeyBytes, err := hex.DecodeString(contact.PublicKey)
+	if err != nil {
+		return fmt.Errorf("invalid public key hex: %w", err)
+	}
+	if len(pubKeyBytes) != ed25519.PublicKeySize {
+		return fmt.Errorf("invalid public key size: expected %d, got %d", ed25519.PublicKeySize, len(pubKeyBytes))
+	}
+
+	// Generate fingerprint (first 8 bytes of public key)
+	contact.Fingerprint = hex.EncodeToString(pubKeyBytes[:8])
+	contact.AddedAt = time.Now()
+	contact.LastSeen = time.Now()
+
+	ab.contacts[contact.PublicKey] = contact
+	return nil
+}
+
+// GetContact retrieves a contact by public key
+func (ab *AddressBook) GetContact(publicKey string) (*Contact, bool) {
+	ab.mu.RLock()
+	defer ab.mu.RUnlock()
+
+	contact, exists := ab.contacts[publicKey]
+	return contact, exists
+}
+
+// GetContactByName retrieves a contact by name (first match)
+func (ab *AddressBook) GetContactByName(name string) (*Contact, bool) {
+	ab.mu.RLock()
+	defer ab.mu.RUnlock()
+
+	for _, contact := range ab.contacts {
+		if contact.Name == name {
+			return contact, true
+		}
+	}
+	return nil, false
+}
+
+// RemoveContact removes a contact from the address book
+func (ab *AddressBook) RemoveContact(publicKey string) bool {
+	ab.mu.Lock()
+	defer ab.mu.Unlock()
+
+	if _, exists := ab.contacts[publicKey]; exists {
+		delete(ab.contacts, publicKey)
+		return true
+	}
+	return false
+}
+
+// UpdateLastSeen updates the last seen timestamp for a contact
+func (ab *AddressBook) UpdateLastSeen(publicKey string) {
+	ab.mu.Lock()
+	defer ab.mu.Unlock()
+
+	if contact, exists := ab.contacts[publicKey]; exists {
+		contact.LastSeen = time.Now()
+	}
+}
+
+// MarkVerified marks a contact as manually verified
+func (ab *AddressBook) MarkVerified(publicKey string, verified bool) error {
+	ab.mu.Lock()
+	defer ab.mu.Unlock()
+
+	contact, exists := ab.contacts[publicKey]
+	if !exists {
+		return fmt.Errorf("contact not found")
+	}
+
+	contact.Verified = verified
+	return nil
+}
+
+// ListContacts returns all contacts
+func (ab *AddressBook) ListContacts() []*Contact {
+	ab.mu.RLock()
+	defer ab.mu.RUnlock()
+
+	contacts := make([]*Contact, 0, len(ab.contacts))
+	for _, contact := range ab.contacts {
+		contacts = append(contacts, contact)
+	}
+	return contacts
+}
+
+// Count returns the number of contacts
+func (ab *AddressBook) Count() int {
+	ab.mu.RLock()
+	defer ab.mu.RUnlock()
+	return len(ab.contacts)
+}
+
+// Clear removes all contacts
+func (ab *AddressBook) Clear() {
+	ab.mu.Lock()
+	defer ab.mu.Unlock()
+	ab.contacts = make(map[string]*Contact)
+}
+
+// VerifyFingerprint checks if a fingerprint matches a public key
+func VerifyFingerprint(publicKeyHex, fingerprint string) bool {
+	pubKeyBytes, err := hex.DecodeString(publicKeyHex)
+	if err != nil {
+		return false
+	}
+	if len(pubKeyBytes) < 8 {
+		return false
+	}
+
+	expectedFingerprint := hex.EncodeToString(pubKeyBytes[:8])
+	return expectedFingerprint == fingerprint
+}
+
+// String returns a string representation
+func (ab *AddressBook) String() string {
+	ab.mu.RLock()
+	defer ab.mu.RUnlock()
+	return fmt.Sprintf("AddressBook(contacts=%d)", len(ab.contacts))
+}