1 files changed, 215 insertions, 0 deletions
diff --git a/api/graphql/models/lazy_bug.go b/api/graphql/models/lazy_bug.go
new file mode 100644
index 00000000..a7840df2
--- /dev/null
+++ b/api/graphql/models/lazy_bug.go
@@ -0,0 +1,215 @@
+package models
+
+import (
+	"sync"
+	"time"
+
+	"github.com/MichaelMure/git-bug/bug"
+	"github.com/MichaelMure/git-bug/cache"
+	"github.com/MichaelMure/git-bug/entity"
+)
+
+// BugWrapper is an interface used by the GraphQL resolvers to handle a bug.
+// Depending on the situation, a Bug can already be fully loaded in memory or not.
+// This interface is used to wrap either a lazyBug or a loadedBug depending on the situation.
+type BugWrapper interface {
+	Id() entity.Id
+	LastEdit() time.Time
+	Status() bug.Status
+	Title() string
+	Comments() ([]bug.Comment, error)
+	Labels() []bug.Label
+	Author() (IdentityWrapper, error)
+	Actors() ([]IdentityWrapper, error)
+	Participants() ([]IdentityWrapper, error)
+	CreatedAt() time.Time
+	Timeline() ([]bug.TimelineItem, error)
+	Operations() ([]bug.Operation, error)
+
+	IsAuthored()
+}
+
+var _ BugWrapper = &lazyBug{}
+
+// lazyBug is a lazy-loading wrapper that fetch data from the cache (BugExcerpt) in priority,
+// and load the complete bug and snapshot only when necessary.
+type lazyBug struct {
+	cache   *cache.RepoCache
+	excerpt *cache.BugExcerpt
+
+	mu   sync.Mutex
+	snap *bug.Snapshot
+}
+
+func NewLazyBug(cache *cache.RepoCache, excerpt *cache.BugExcerpt) *lazyBug {
+	return &lazyBug{
+		cache:   cache,
+		excerpt: excerpt,
+	}
+}
+
+func (lb *lazyBug) load() error {
+	if lb.snap != nil {
+		return nil
+	}
+
+	lb.mu.Lock()
+	defer lb.mu.Unlock()
+
+	b, err := lb.cache.ResolveBug(lb.excerpt.Id)
+	if err != nil {
+		return err
+	}
+
+	lb.snap = b.Snapshot()
+	return nil
+}
+
+func (lb *lazyBug) identity(id entity.Id) (IdentityWrapper, error) {
+	i, err := lb.cache.ResolveIdentityExcerpt(id)
+	if err != nil {
+		return nil, err
+	}
+	return &lazyIdentity{cache: lb.cache, excerpt: i}, nil
+}
+
+// Sign post method for gqlgen
+func (lb *lazyBug) IsAuthored() {}
+
+func (lb *lazyBug) Id() entity.Id {
+	return lb.excerpt.Id
+}
+
+func (lb *lazyBug) LastEdit() time.Time {
+	return lb.excerpt.EditTime()
+}
+
+func (lb *lazyBug) Status() bug.Status {
+	return lb.excerpt.Status
+}
+
+func (lb *lazyBug) Title() string {
+	return lb.excerpt.Title
+}
+
+func (lb *lazyBug) Comments() ([]bug.Comment, error) {
+	err := lb.load()
+	if err != nil {
+		return nil, err
+	}
+	return lb.snap.Comments, nil
+}
+
+func (lb *lazyBug) Labels() []bug.Label {
+	return lb.excerpt.Labels
+}
+
+func (lb *lazyBug) Author() (IdentityWrapper, error) {
+	return lb.identity(lb.excerpt.AuthorId)
+}
+
+func (lb *lazyBug) Actors() ([]IdentityWrapper, error) {
+	result := make([]IdentityWrapper, len(lb.excerpt.Actors))
+	for i, actorId := range lb.excerpt.Actors {
+		actor, err := lb.identity(actorId)
+		if err != nil {
+			return nil, err
+		}
+		result[i] = actor
+	}
+	return result, nil
+}
+
+func (lb *lazyBug) Participants() ([]IdentityWrapper, error) {
+	result := make([]IdentityWrapper, len(lb.excerpt.Participants))
+	for i, participantId := range lb.excerpt.Participants {
+		participant, err := lb.identity(participantId)
+		if err != nil {
+			return nil, err
+		}
+		result[i] = participant
+	}
+	return result, nil
+}
+
+func (lb *lazyBug) CreatedAt() time.Time {
+	return lb.excerpt.CreateTime()
+}
+
+func (lb *lazyBug) Timeline() ([]bug.TimelineItem, error) {
+	err := lb.load()
+	if err != nil {
+		return nil, err
+	}
+	return lb.snap.Timeline, nil
+}
+
+func (lb *lazyBug) Operations() ([]bug.Operation, error) {
+	err := lb.load()
+	if err != nil {
+		return nil, err
+	}
+	return lb.snap.Operations, nil
+}
+
+var _ BugWrapper = &loadedBug{}
+
+type loadedBug struct {
+	*bug.Snapshot
+}
+
+func NewLoadedBug(snap *bug.Snapshot) *loadedBug {
+	return &loadedBug{Snapshot: snap}
+}
+
+func (l *loadedBug) LastEdit() time.Time {
+	return l.Snapshot.EditTime()
+}
+
+func (l *loadedBug) Status() bug.Status {
+	return l.Snapshot.Status
+}
+
+func (l *loadedBug) Title() string {
+	return l.Snapshot.Title
+}
+
+func (l *loadedBug) Comments() ([]bug.Comment, error) {
+	return l.Snapshot.Comments, nil
+}
+
+func (l *loadedBug) Labels() []bug.Label {
+	return l.Snapshot.Labels
+}
+
+func (l *loadedBug) Author() (IdentityWrapper, error) {
+	return NewLoadedIdentity(l.Snapshot.Author), nil
+}
+
+func (l *loadedBug) Actors() ([]IdentityWrapper, error) {
+	res := make([]IdentityWrapper, len(l.Snapshot.Actors))
+	for i, actor := range l.Snapshot.Actors {
+		res[i] = NewLoadedIdentity(actor)
+	}
+	return res, nil
+}
+
+func (l *loadedBug) Participants() ([]IdentityWrapper, error) {
+	res := make([]IdentityWrapper, len(l.Snapshot.Participants))
+	for i, participant := range l.Snapshot.Participants {
+		res[i] = NewLoadedIdentity(participant)
+	}
+	return res, nil
+}
+
+func (l *loadedBug) CreatedAt() time.Time {
+	return l.Snapshot.CreateTime
+}
+
+func (l *loadedBug) Timeline() ([]bug.TimelineItem, error) {
+	return l.Snapshot.Timeline, nil
+}
+
+func (l *loadedBug) Operations() ([]bug.Operation, error) {
+	return l.Snapshot.Operations, nil
+}