1 files changed, 242 insertions, 0 deletions
diff --git a/bridge/gitlab/iterator.go b/bridge/gitlab/iterator.go
new file mode 100644
index 00000000..883fea9c
--- /dev/null
+++ b/bridge/gitlab/iterator.go
@@ -0,0 +1,242 @@
+package gitlab
+
+import (
+	"time"
+
+	"github.com/xanzy/go-gitlab"
+)
+
+type issueIterator struct {
+	page  int
+	index int
+	cache []*gitlab.Issue
+}
+
+type noteIterator struct {
+	page  int
+	index int
+	cache []*gitlab.Note
+}
+
+type labelEventIterator struct {
+	page  int
+	index int
+	cache []*gitlab.LabelEvent
+}
+
+type iterator struct {
+	// gitlab api v4 client
+	gc *gitlab.Client
+
+	// if since is given the iterator will query only the issues
+	// updated after this date
+	since time.Time
+
+	// project id
+	project string
+
+	// number of issues and notes to query at once
+	capacity int
+
+	// sticky error
+	err error
+
+	// issues iterator
+	issue *issueIterator
+
+	// notes iterator
+	note *noteIterator
+
+	// labelEvent iterator
+	labelEvent *labelEventIterator
+}
+
+// NewIterator create a new iterator
+func NewIterator(projectID, token string, since time.Time) *iterator {
+	return &iterator{
+		gc:       buildClient(token),
+		project:  projectID,
+		since:    since,
+		capacity: 20,
+		issue: &issueIterator{
+			index: -1,
+			page:  1,
+		},
+		note: &noteIterator{
+			index: -1,
+			page:  1,
+		},
+		labelEvent: &labelEventIterator{
+			index: -1,
+			page:  1,
+		},
+	}
+}
+
+// Error return last encountered error
+func (i *iterator) Error() error {
+	return i.err
+}
+
+func (i *iterator) getNextIssues() bool {
+	issues, _, err := i.gc.Issues.ListProjectIssues(
+		i.project,
+		&gitlab.ListProjectIssuesOptions{
+			ListOptions: gitlab.ListOptions{
+				Page:    i.issue.page,
+				PerPage: i.capacity,
+			},
+			Scope:        gitlab.String("all"),
+			UpdatedAfter: &i.since,
+			Sort:         gitlab.String("asc"),
+		},
+	)
+
+	if err != nil {
+		i.err = err
+		return false
+	}
+
+	// if repository doesn't have any issues
+	if len(issues) == 0 {
+		return false
+	}
+
+	i.issue.cache = issues
+	i.issue.index = 0
+	i.issue.page++
+	i.note.index = -1
+	i.note.cache = nil
+
+	return true
+}
+
+func (i *iterator) NextIssue() bool {
+	if i.err != nil {
+		return false
+	}
+
+	// first query
+	if i.issue.cache == nil {
+		return i.getNextIssues()
+	}
+
+	// move cursor index
+	if i.issue.index < len(i.issue.cache)-1 {
+		i.issue.index++
+		return true
+	}
+
+	return i.getNextIssues()
+}
+
+func (i *iterator) IssueValue() *gitlab.Issue {
+	return i.issue.cache[i.issue.index]
+}
+
+func (i *iterator) getNextNotes() bool {
+	notes, _, err := i.gc.Notes.ListIssueNotes(
+		i.project,
+		i.IssueValue().IID,
+		&gitlab.ListIssueNotesOptions{
+			ListOptions: gitlab.ListOptions{
+				Page:    i.note.page,
+				PerPage: i.capacity,
+			},
+			Sort:    gitlab.String("asc"),
+			OrderBy: gitlab.String("created_at"),
+		},
+	)
+
+	if err != nil {
+		i.err = err
+		return false
+	}
+
+	if len(notes) == 0 {
+		i.note.index = -1
+		i.note.page = 1
+		i.note.cache = nil
+		return false
+	}
+
+	i.note.cache = notes
+	i.note.page++
+	i.note.index = 0
+	return true
+}
+
+func (i *iterator) NextNote() bool {
+	if i.err != nil {
+		return false
+	}
+
+	if len(i.note.cache) == 0 {
+		return i.getNextNotes()
+	}
+
+	// move cursor index
+	if i.note.index < len(i.note.cache)-1 {
+		i.note.index++
+		return true
+	}
+
+	return i.getNextNotes()
+}
+
+func (i *iterator) NoteValue() *gitlab.Note {
+	return i.note.cache[i.note.index]
+}
+
+func (i *iterator) getNextLabelEvents() bool {
+	labelEvents, _, err := i.gc.ResourceLabelEvents.ListIssueLabelEvents(
+		i.project,
+		i.IssueValue().IID,
+		&gitlab.ListLabelEventsOptions{
+			ListOptions: gitlab.ListOptions{
+				Page:    i.labelEvent.page,
+				PerPage: i.capacity,
+			},
+		},
+	)
+
+	if err != nil {
+		i.err = err
+		return false
+	}
+
+	if len(labelEvents) == 0 {
+		i.labelEvent.page = 1
+		i.labelEvent.index = -1
+		i.labelEvent.cache = nil
+		return false
+	}
+
+	i.labelEvent.cache = labelEvents
+	i.labelEvent.page++
+	i.labelEvent.index = 0
+	return true
+}
+
+// because Gitlab
+func (i *iterator) NextLabelEvent() bool {
+	if i.err != nil {
+		return false
+	}
+
+	if len(i.labelEvent.cache) == 0 {
+		return i.getNextLabelEvents()
+	}
+
+	// move cursor index
+	if i.labelEvent.index < len(i.labelEvent.cache)-1 {
+		i.labelEvent.index++
+		return true
+	}
+
+	return i.getNextLabelEvents()
+}
+
+func (i *iterator) LabelEventValue() *gitlab.LabelEvent {
+	return i.labelEvent.cache[i.labelEvent.index]
+}