初始提交：边缘AI算力机统一AI通讯层

internal/session/session.go

@@ -0,0 +1,172 @@
+package session
+
+import (
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/edgeai/gateway/pkg/api"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// Session represents a conversation session.
+type Session struct {
+	ID            string
+	ApplicationID string
+	TenantID      string
+	UserID        string
+	Messages      []api.Message
+	Config        map[string]any
+	CreatedAt     time.Time
+	LastActive    time.Time
+}
+
+// Store manages session persistence with SQLite.
+type Store struct {
+	mu sync.RWMutex
+	db *sql.DB
+}
+
+// NewStore creates a new session store.
+func NewStore(dbPath string) (*Store, error) {
+	db, err := sql.Open("sqlite3", dbPath)
+	if err != nil {
+		return nil, fmt.Errorf("open session db: %w", err)
+	}
+
+	if err := initSessionDB(db); err != nil {
+		return nil, fmt.Errorf("init session db: %w", err)
+	}
+
+	return &Store{db: db}, nil
+}
+
+func initSessionDB(db *sql.DB) error {
+	schema := `
+	CREATE TABLE IF NOT EXISTS sessions (
+		id TEXT PRIMARY KEY,
+		application_id TEXT NOT NULL,
+		tenant_id TEXT NOT NULL,
+		user_id TEXT,
+		messages TEXT NOT NULL DEFAULT '[]',
+		config TEXT NOT NULL DEFAULT '{}',
+		created_at TEXT NOT NULL,
+		last_active TEXT NOT NULL
+	);
+	CREATE INDEX IF NOT EXISTS idx_sessions_app ON sessions(application_id);
+	CREATE INDEX IF NOT EXISTS idx_sessions_tenant ON sessions(tenant_id);
+	CREATE INDEX IF NOT EXISTS idx_sessions_last_active ON sessions(last_active);`
+	_, err := db.Exec(schema)
+	return err
+}
+
+// Create creates a new session.
+func (s *Store) Create(id, appID, tenantID, userID string, config map[string]any) (*Session, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	now := time.Now()
+	session := &Session{
+		ID:            id,
+		ApplicationID: appID,
+		TenantID:      tenantID,
+		UserID:        userID,
+		Messages:      []api.Message{},
+		Config:        config,
+		CreatedAt:     now,
+		LastActive:    now,
+	}
+
+	configJSON, _ := json.Marshal(config)
+	msgsJSON, _ := json.Marshal(session.Messages)
+
+	_, err := s.db.Exec(
+		`INSERT INTO sessions (id, application_id, tenant_id, user_id, messages, config, created_at, last_active)
+		 VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
+		id, appID, tenantID, userID, string(msgsJSON), string(configJSON), now.Format(time.RFC3339), now.Format(time.RFC3339),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("insert session: %w", err)
+	}
+
+	return session, nil
+}
+
+// Get retrieves a session by ID.
+func (s *Store) Get(id string) (*Session, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	var (
+		appID, tenantID, userID, msgsJSON, configJSON, createdAt, lastActive string
+	)
+
+	err := s.db.QueryRow(
+		`SELECT application_id, tenant_id, user_id, messages, config, created_at, last_active FROM sessions WHERE id = ?`,
+		id,
+	).Scan(&appID, &tenantID, &userID, &msgsJSON, &configJSON, &createdAt, &lastActive)
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("query session: %w", err)
+	}
+
+	session := &Session{
+		ID:            id,
+		ApplicationID: appID,
+		TenantID:      tenantID,
+		UserID:        userID,
+		CreatedAt:     parseTime(createdAt),
+		LastActive:    parseTime(lastActive),
+	}
+	json.Unmarshal([]byte(msgsJSON), &session.Messages)
+	json.Unmarshal([]byte(configJSON), &session.Config)
+
+	return session, nil
+}
+
+// AddMessage appends a message to the session and updates last_active.
+func (s *Store) AddMessage(id string, msg api.Message) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	session, err := s.Get(id)
+	if err != nil {
+		return err
+	}
+	if session == nil {
+		return fmt.Errorf("session not found: %s", id)
+	}
+
+	session.Messages = append(session.Messages, msg)
+	msgsJSON, _ := json.Marshal(session.Messages)
+	now := time.Now().Format(time.RFC3339)
+
+	_, err = s.db.Exec(
+		`UPDATE sessions SET messages = ?, last_active = ? WHERE id = ?`,
+		string(msgsJSON), now, id,
+	)
+	return err
+}
+
+// Delete removes a session.
+func (s *Store) Delete(id string) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	_, err := s.db.Exec(`DELETE FROM sessions WHERE id = ?`, id)
+	return err
+}
+
+// Close closes the database connection.
+func (s *Store) Close() error {
+	return s.db.Close()
+}
+
+func parseTime(s string) time.Time {
+	t, _ := time.Parse(time.RFC3339, s)
+	return t
+}