feat: list merge requests of current brnach

cmd/app/list_discussions.go

@@ -85,10 +85,7 @@ func (a discussionsListerService) ServeHTTP(w http.ResponseWriter, r *http.Reque
 	request := r.Context().Value(payload(payload("payload"))).(*DiscussionsRequest)
 
 	mergeRequestDiscussionOptions := gitlab.ListMergeRequestDiscussionsOptions{
-		ListOptions: gitlab.ListOptions{
-			Page:    1,
-			PerPage: 250,
-		},
+		ListOptions: gitlab.ListOptions{},
 	}
 
 	it, hasErr := gitlab.Scan(func(p gitlab.PaginationOptionFunc) ([]*gitlab.Discussion, *gitlab.Response, error) {

cmd/app/merge_requests_by_branch.go

@@ -0,0 +1,120 @@
+package app
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"sync"
+
+	gitlab "gitlab.com/gitlab-org/api/client-go"
+)
+
+type MergeRequestListerByBranch interface {
+	ListProjectMergeRequests(pid interface{}, opt *gitlab.ListProjectMergeRequestsOptions, options ...gitlab.RequestOptionFunc) ([]*gitlab.BasicMergeRequest, *gitlab.Response, error)
+}
+
+type mergeRequestListerByBranchService struct {
+	data
+	client MergeRequestListerByBranch
+}
+
+type MergeRequestByBranchRequest struct {
+	Branch string `json:"branch" validate:"required"`
+	State  string `json:"state,omitempty"`
+}
+
+// Returns a list of merge requests where the given branch is the source branch
+func (a mergeRequestListerByBranchService) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+
+	request := r.Context().Value(payload("payload")).(*MergeRequestByBranchRequest)
+
+	if request.State == "" {
+		request.State = "opened"
+	}
+
+	payloads := []gitlab.ListProjectMergeRequestsOptions{
+		{
+			SourceBranch: gitlab.Ptr(request.Branch),
+			State:        gitlab.Ptr(request.State),
+			Scope:        gitlab.Ptr("all"),
+		},
+	}
+
+	type apiResponse struct {
+		mrs []*gitlab.BasicMergeRequest
+		err error
+	}
+
+	mrChan := make(chan apiResponse, len(payloads))
+	wg := sync.WaitGroup{}
+	go func() {
+		wg.Wait()
+		close(mrChan)
+	}()
+
+	for _, payload := range payloads {
+		wg.Add(1)
+		go func(p gitlab.ListProjectMergeRequestsOptions) {
+			defer wg.Done()
+			mrs, err := a.getMrs(&p)
+			mrChan <- apiResponse{mrs, err}
+		}(payload)
+	}
+
+	var mergeRequests []*gitlab.BasicMergeRequest
+	existingIds := make(map[int64]bool)
+	var errs []error
+	for res := range mrChan {
+		if res.err != nil {
+			errs = append(errs, res.err)
+		} else {
+			for _, mr := range res.mrs {
+				if !existingIds[mr.ID] {
+					mergeRequests = append(mergeRequests, mr)
+					existingIds[mr.ID] = true
+				}
+			}
+		}
+	}
+
+	if len(errs) > 0 {
+		combinedErr := ""
+		for _, err := range errs {
+			combinedErr += err.Error() + "; "
+		}
+		handleError(w, errors.New(combinedErr), "An error occurred", http.StatusInternalServerError)
+		return
+	}
+
+	if len(mergeRequests) == 0 {
+		handleError(w, fmt.Errorf("%s did not have any MRs", request.Branch), "No MRs found", http.StatusNotFound)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+	response := ListMergeRequestResponse{
+		SuccessResponse: SuccessResponse{Message: fmt.Sprintf("Merge requests fetched for %s", request.Branch)},
+		MergeRequests:   mergeRequests,
+	}
+
+	err := json.NewEncoder(w).Encode(response)
+	if err != nil {
+		handleError(w, err, "Could not encode response", http.StatusInternalServerError)
+	}
+}
+
+func (a mergeRequestListerByBranchService) getMrs(payload *gitlab.ListProjectMergeRequestsOptions) ([]*gitlab.BasicMergeRequest, error) {
+	mrs, res, err := a.client.ListProjectMergeRequests(a.projectInfo.ProjectId, payload)
+	if err != nil {
+		return []*gitlab.BasicMergeRequest{}, err
+	}
+
+	if res.StatusCode >= 300 {
+		return []*gitlab.BasicMergeRequest{}, GenericError{endpoint: "/merge_requests_by_branch"}
+	}
+
+	defer res.Body.Close()
+
+	return mrs, err
+}

cmd/app/server.go

@@ -233,6 +233,11 @@ func CreateRouter(gitlabClient *Client, projectInfo *ProjectInfo, s *shutdownSer
 		withPayloadValidation(methodToPayload{http.MethodPost: newPayload[gitlab.ListProjectMergeRequestsOptions]}), // TODO: How to validate external object
 		withMethodCheck(http.MethodPost),
 	))
+	m.HandleFunc("/merge_requests_by_branch", middleware(
+		mergeRequestListerByBranchService{d, gitlabClient},
+		withPayloadValidation(methodToPayload{http.MethodPost: newPayload[MergeRequestByBranchRequest]}),
+		withMethodCheck(http.MethodPost),
+	))
 	m.HandleFunc("/merge_requests_by_username", middleware(
 		mergeRequestListerByUsernameService{d, gitlabClient},
 		withPayloadValidation(methodToPayload{http.MethodPost: newPayload[MergeRequestByUsernameRequest]}),