feat(k9): Define domain model structs (Media, User, Set, Tag, Session, Share, Note) in internal/model/ with zero external deps

3 files changed, 167 insertions, 2 deletions

diff --git a/internal/model/media.go b/internal/model/media.go
new file mode 100644
index 0000000..cae1c8d
--- /dev/null
+++ b/internal/model/media.go
@@ -0,0 +1,140 @@
+// Package model defines the core domain entities.
+package model
+
+import "time"
+
+// MediaType distinguishes between video and audio files.
+type MediaType string
+
+const (
+	MediaTypeVideo MediaType = "video"
+	MediaTypeAudio MediaType = "audio"
+)
+
+// Role defines the level of access a user has to a set.
+type Role string
+
+const (
+	RoleOwner  Role = "owner"
+	RoleViewer Role = "viewer"
+)
+
+// User represents an application account.
+type User struct {
+	ID           int64
+	Username     string
+	PasswordHash string
+	IsAdmin      bool
+	CreatedAt    time.Time
+}
+
+// Set represents a top-level media collection (a directory under MEDIA_ROOT).
+type Set struct {
+	ID                 int64
+	Name               string
+	RootPath           string
+	CoverThumbnailPath string
+	CreatedAt          time.Time
+}
+
+// SetPermission grants a user access to a set.
+type SetPermission struct {
+	SetID     int64
+	UserID    int64
+	Role      Role
+	CreatedAt time.Time
+}
+
+// Media represents a single audio or video file within a set.
+type Media struct {
+	ID            int64
+	SetID         int64
+	RelPath       string
+	FileName      string
+	AbsPath       string
+	Type          MediaType
+	Duration      float64
+	Codec         string
+	Resolution    string
+	Bitrate       int
+	FileSizeBytes int64
+	ThumbnailPath string
+	PlayCount     int
+	DeletedAt     *time.Time
+	CreatedAt     time.Time
+}
+
+// Tag is a label that can be attached to media items.
+type Tag struct {
+	ID   int64
+	Name string
+}
+
+// Session is an authenticated browser session.
+type Session struct {
+	ID        string
+	UserID    int64
+	ExpiresAt time.Time
+	CreatedAt time.Time
+}
+
+// Share is a time-bounded public link to a media item.
+type Share struct {
+	Token     string
+	MediaID   int64
+	CreatedBy int64
+	CreatedAt time.Time
+	ExpiresAt time.Time
+	MaxUses   *int
+	UsedCount int
+}
+
+// Note is a per-user, per-media text note.
+type Note struct {
+	ID        int64
+	MediaID   int64
+	UserID    int64
+	Content   string
+	CreatedAt time.Time
+	UpdatedAt time.Time
+}
+
+// PlaybackProgress stores the last known playback position.
+type PlaybackProgress struct {
+	UserID          int64
+	MediaID         int64
+	PositionSeconds float64
+	UpdatedAt       time.Time
+}
+
+// PlaybackAccumulator tracks deltas for the 60-second playback counter rule.
+type PlaybackAccumulator struct {
+	SessionID          string
+	MediaID            int64
+	LastPosition       float64
+	AccumulatedSeconds float64
+	Counted            bool
+	UpdatedAt          time.Time
+}
+
+// Favorite records that a user has favorited a media item.
+type Favorite struct {
+	UserID    int64
+	MediaID   int64
+	CreatedAt time.Time
+}
+
+// MediaTag is the join table between media and tags.
+type MediaTag struct {
+	MediaID int64
+	TagID   int64
+}
+
+// Metadata holds extracted file properties from ffprobe and os.Stat.
+type Metadata struct {
+	Duration      float64
+	Codec         string
+	Resolution    string
+	Bitrate       int
+	FileSizeBytes int64
+}
diff --git a/internal/model/media_test.go b/internal/model/media_test.go
new file mode 100644
index 0000000..49d877c
--- /dev/null
+++ b/internal/model/media_test.go
@@ -0,0 +1,27 @@
+package model
+
+import (
+	"testing"
+	"time"
+)
+
+func TestStructsInstantiate(t *testing.T) {
+	now := time.Now()
+	_ = User{ID: 1, Username: "u", PasswordHash: "h", IsAdmin: true, CreatedAt: now}
+	_ = Set{ID: 1, Name: "s", RootPath: "/r", CreatedAt: now}
+	_ = Media{ID: 1, SetID: 1, RelPath: "r", FileName: "f", AbsPath: "a", Type: MediaTypeVideo, Duration: 1, DeletedAt: &now, CreatedAt: now}
+	_ = Tag{ID: 1, Name: "t"}
+	_ = Session{ID: "s", UserID: 1, ExpiresAt: now, CreatedAt: now}
+	max := 1
+	_ = Share{Token: "t", MediaID: 1, CreatedBy: 1, CreatedAt: now, ExpiresAt: now, MaxUses: &max}
+	_ = Note{ID: 1, MediaID: 1, UserID: 1, Content: "c", CreatedAt: now, UpdatedAt: now}
+	_ = PlaybackProgress{UserID: 1, MediaID: 1, PositionSeconds: 1, UpdatedAt: now}
+	_ = PlaybackAccumulator{SessionID: "s", MediaID: 1, UpdatedAt: now}
+	_ = Favorite{UserID: 1, MediaID: 1, CreatedAt: now}
+	_ = MediaTag{MediaID: 1, TagID: 1}
+	_ = SetPermission{SetID: 1, UserID: 1, Role: RoleOwner, CreatedAt: now}
+	_ = Metadata{Duration: 1, Codec: "c", Resolution: "r", Bitrate: 1, FileSizeBytes: 1}
+	if MediaTypeVideo != "video" || MediaTypeAudio != "audio" || RoleOwner != "owner" || RoleViewer != "viewer" {
+		t.Fatal("constants mismatch")
+	}
+}
diff --git a/internal/model/model.go b/internal/model/model.go
deleted file mode 100644
index 8061bf6..0000000
--- a/internal/model/model.go
+++ /dev/null
@@ -1,2 +0,0 @@
-// Package model defines the core domain entities.
-package model