Add models package with embedded DB interface pattern

- internal/models/model.go: DB interface + Base struct for all models
- internal/models/channel.go: Channel model with DB access for relation queries
- Database.NewChannel() factory injects db reference into model instances
- Uses interface to avoid circular imports (models -> db)

internal/db/db.go

@@ -5,6 +5,7 @@ import (
 	"database/sql"
 	"embed"
 	"fmt"
+	"time"
 	"io/fs"
 	"log/slog"
 	"sort"
@@ -13,6 +14,7 @@ import (
 
 	"git.eeqj.de/sneak/chat/internal/config"
 	"git.eeqj.de/sneak/chat/internal/logger"
+	"git.eeqj.de/sneak/chat/internal/models"
 	"go.uber.org/fx"
 
 	_ "github.com/joho/godotenv/autoload"
@@ -29,11 +31,30 @@ type DatabaseParams struct {
 }
 
 type Database struct {
-	DB     *sql.DB
+	db     *sql.DB
 	log    *slog.Logger
 	params *DatabaseParams
 }
 
+// GetDB implements models.db so Database can be embedded in model structs.
+func (s *Database) GetDB() *sql.DB {
+	return s.db
+}
+
+// NewChannel creates a Channel model instance with the db reference injected.
+func (s *Database) NewChannel(id int64, name, topic, modes string, createdAt, updatedAt time.Time) *models.Channel {
+	c := &models.Channel{
+		ID:        id,
+		Name:      name,
+		Topic:     topic,
+		Modes:     modes,
+		CreatedAt: createdAt,
+		UpdatedAt: updatedAt,
+	}
+	c.SetDB(s)
+	return c
+}
+
 func New(lc fx.Lifecycle, params DatabaseParams) (*Database, error) {
 	s := new(Database)
 	s.params = &params
@@ -48,8 +69,8 @@ func New(lc fx.Lifecycle, params DatabaseParams) (*Database, error) {
 		},
 		OnStop: func(ctx context.Context) error {
 			s.log.Info("Database OnStop Hook")
-			if s.DB != nil {
+			if s.db != nil {
-				return s.DB.Close()
+				return s.db.Close()
 			}
 			return nil
 		},
@@ -76,7 +97,7 @@ func (s *Database) connect(ctx context.Context) error {
 		return err
 	}
 
-	s.DB = d
+	s.db = d
 	s.log.Info("database connected")
 
 	return s.runMigrations(ctx)
@@ -91,7 +112,7 @@ type migration struct {
 func (s *Database) runMigrations(ctx context.Context) error {
 	// Bootstrap: create schema_migrations table directly (migration 001 also does this,
 	// but we need it to exist before we can check which migrations have run)
-	_, err := s.DB.ExecContext(ctx, `CREATE TABLE IF NOT EXISTS schema_migrations (
+	_, err := s.db.ExecContext(ctx, `CREATE TABLE IF NOT EXISTS schema_migrations (
 		version INTEGER PRIMARY KEY,
 		applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
 	)`)
@@ -139,7 +160,7 @@ func (s *Database) runMigrations(ctx context.Context) error {
 
 	for _, m := range migrations {
 		var exists int
-		err := s.DB.QueryRowContext(ctx, "SELECT COUNT(*) FROM schema_migrations WHERE version = ?", m.version).Scan(&exists)
+		err := s.db.QueryRowContext(ctx, "SELECT COUNT(*) FROM schema_migrations WHERE version = ?", m.version).Scan(&exists)
 		if err != nil {
 			return fmt.Errorf("failed to check migration %d: %w", m.version, err)
 		}
@@ -148,10 +169,10 @@ func (s *Database) runMigrations(ctx context.Context) error {
 		}
 
 		s.log.Info("applying migration", "version", m.version, "name", m.name)
-		if _, err := s.DB.ExecContext(ctx, m.sql); err != nil {
+		if _, err := s.db.ExecContext(ctx, m.sql); err != nil {
 			return fmt.Errorf("failed to apply migration %d (%s): %w", m.version, m.name, err)
 		}
-		if _, err := s.DB.ExecContext(ctx, "INSERT INTO schema_migrations (version) VALUES (?)", m.version); err != nil {
+		if _, err := s.db.ExecContext(ctx, "INSERT INTO schema_migrations (version) VALUES (?)", m.version); err != nil {
 			return fmt.Errorf("failed to record migration %d: %w", m.version, err)
 		}
 	}
@@ -159,3 +180,4 @@ func (s *Database) runMigrations(ctx context.Context) error {
 	s.log.Info("database migrations complete")
 	return nil
 }
+

internal/models/channel.go

@@ -0,0 +1,21 @@
+package models
+
+import (
+	"time"
+)
+
+// Channel represents a chat channel.
+type Channel struct {
+	Base
+	ID        int64     `json:"id"`
+	Name      string    `json:"name"`
+	Topic     string    `json:"topic"`
+	Modes     string    `json:"modes"`
+	CreatedAt time.Time `json:"created_at"`
+	UpdatedAt time.Time `json:"updated_at"`
+}
+
+// Example relation method — will be fleshed out when we add channel_members:
+// func (c *Channel) Members(ctx context.Context) ([]*User, error) {
+//     return c.DB().GetChannelMembers(ctx, c.ID)
+// }

internal/models/model.go

@@ -0,0 +1,18 @@
+package models
+
+import "database/sql"
+
+// DB is the interface that models use to query relations.
+// This avoids a circular import with the db package.
+type DB interface {
+	GetDB() *sql.DB
+}
+
+// Base is embedded in all model structs to provide database access.
+type Base struct {
+	db DB
+}
+
+func (b *Base) SetDB(d DB) {
+	b.db = d
+}