1 files changed, 215 insertions, 0 deletions
diff --git a/bridge/gitlab/event.go b/bridge/gitlab/event.go
new file mode 100644
index 00000000..80663edd
--- /dev/null
+++ b/bridge/gitlab/event.go
@@ -0,0 +1,215 @@
+package gitlab
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/MichaelMure/git-bug/util/text"
+	"github.com/xanzy/go-gitlab"
+)
+
+// Event represents a unified GitLab event (note, label or state event).
+type Event interface {
+	ID() string
+	UserID() int
+	Kind() EventKind
+	CreatedAt() time.Time
+}
+
+type EventKind int
+
+const (
+	EventUnknown EventKind = iota
+	EventError
+	EventComment
+	EventTitleChanged
+	EventDescriptionChanged
+	EventClosed
+	EventReopened
+	EventLocked
+	EventUnlocked
+	EventChangedDuedate
+	EventRemovedDuedate
+	EventAssigned
+	EventUnassigned
+	EventChangedMilestone
+	EventRemovedMilestone
+	EventAddLabel
+	EventRemoveLabel
+	EventMentionedInIssue
+	EventMentionedInMergeRequest
+)
+
+var _ Event = &NoteEvent{}
+
+type NoteEvent struct{ gitlab.Note }
+
+func (n NoteEvent) ID() string           { return fmt.Sprintf("%d", n.Note.ID) }
+func (n NoteEvent) UserID() int          { return n.Author.ID }
+func (n NoteEvent) CreatedAt() time.Time { return *n.Note.CreatedAt }
+func (n NoteEvent) Kind() EventKind {
+
+	switch {
+	case !n.System:
+		return EventComment
+
+	case n.Body == "closed":
+		return EventClosed
+
+	case n.Body == "reopened":
+		return EventReopened
+
+	case n.Body == "changed the description":
+		return EventDescriptionChanged
+
+	case n.Body == "locked this issue":
+		return EventLocked
+
+	case n.Body == "unlocked this issue":
+		return EventUnlocked
+
+	case strings.HasPrefix(n.Body, "changed title from"):
+		return EventTitleChanged
+
+	case strings.HasPrefix(n.Body, "changed due date to"):
+		return EventChangedDuedate
+
+	case n.Body == "removed due date":
+		return EventRemovedDuedate
+
+	case strings.HasPrefix(n.Body, "assigned to @"):
+		return EventAssigned
+
+	case strings.HasPrefix(n.Body, "unassigned @"):
+		return EventUnassigned
+
+	case strings.HasPrefix(n.Body, "changed milestone to %"):
+		return EventChangedMilestone
+
+	case strings.HasPrefix(n.Body, "removed milestone"):
+		return EventRemovedMilestone
+
+	case strings.HasPrefix(n.Body, "mentioned in issue"):
+		return EventMentionedInIssue
+
+	case strings.HasPrefix(n.Body, "mentioned in merge request"):
+		return EventMentionedInMergeRequest
+
+	default:
+		return EventUnknown
+	}
+
+}
+
+func (n NoteEvent) Title() string {
+	if n.Kind() == EventTitleChanged {
+		return getNewTitle(n.Body)
+	}
+	return text.CleanupOneLine(n.Body)
+}
+
+var _ Event = &LabelEvent{}
+
+type LabelEvent struct{ gitlab.LabelEvent }
+
+func (l LabelEvent) ID() string           { return fmt.Sprintf("%d", l.LabelEvent.ID) }
+func (l LabelEvent) UserID() int          { return l.User.ID }
+func (l LabelEvent) CreatedAt() time.Time { return *l.LabelEvent.CreatedAt }
+func (l LabelEvent) Kind() EventKind {
+	switch l.Action {
+	case "add":
+		return EventAddLabel
+	case "remove":
+		return EventRemoveLabel
+	default:
+		return EventUnknown
+	}
+}
+
+var _ Event = &StateEvent{}
+
+type StateEvent struct{ gitlab.StateEvent }
+
+func (s StateEvent) ID() string           { return fmt.Sprintf("%d", s.StateEvent.ID) }
+func (s StateEvent) UserID() int          { return s.User.ID }
+func (s StateEvent) CreatedAt() time.Time { return *s.StateEvent.CreatedAt }
+func (s StateEvent) Kind() EventKind {
+	switch s.State {
+	case "closed":
+		return EventClosed
+	case "opened", "reopened":
+		return EventReopened
+	default:
+		return EventUnknown
+	}
+}
+
+var _ Event = &ErrorEvent{}
+
+type ErrorEvent struct {
+	Err  error
+	Time time.Time
+}
+
+func (e ErrorEvent) ID() string           { return "" }
+func (e ErrorEvent) UserID() int          { return -1 }
+func (e ErrorEvent) CreatedAt() time.Time { return e.Time }
+func (e ErrorEvent) Kind() EventKind      { return EventError }
+
+// SortedEvents fan-in some Event-channels into one, sorted by creation date, using CreatedAt-method.
+// This function assume that each channel is pre-ordered.
+func SortedEvents(inputs ...<-chan Event) chan Event {
+	out := make(chan Event)
+
+	go func() {
+		defer close(out)
+
+		heads := make([]Event, len(inputs))
+
+		// pre-fill the head view
+		for i, input := range inputs {
+			if event, ok := <-input; ok {
+				heads[i] = event
+			}
+		}
+
+		for {
+			var earliestEvent Event
+			var originChannel int
+
+			// pick the earliest event of the heads
+			for i, head := range heads {
+				if head != nil && (earliestEvent == nil || head.CreatedAt().Before(earliestEvent.CreatedAt())) {
+					earliestEvent = head
+					originChannel = i
+				}
+			}
+
+			if earliestEvent == nil {
+				// no event anymore, we are done
+				return
+			}
+
+			// we have an event: consume it and replace it if possible
+			heads[originChannel] = nil
+			if event, ok := <-inputs[originChannel]; ok {
+				heads[originChannel] = event
+			}
+			out <- earliestEvent
+		}
+	}()
+
+	return out
+}
+
+// getNewTitle parses body diff given by gitlab api and return it final form
+// examples: "changed title from **fourth issue** to **fourth issue{+ changed+}**"
+//           "changed title from **fourth issue{- changed-}** to **fourth issue**"
+// because Gitlab
+func getNewTitle(diff string) string {
+	newTitle := strings.Split(diff, "** to **")[1]
+	newTitle = strings.Replace(newTitle, "{+", "", -1)
+	newTitle = strings.Replace(newTitle, "+}", "", -1)
+	return strings.TrimSuffix(newTitle, "**")
+}