Fix MR Selection, Go Code Refactor (#358)

refactor: Refactors the Go codebase into a more modular and idiomatic approach
fix: require selection of specific MR when there are multiple targets for a given source branch
feat: Allows for the passing of Gitlab's filter options when choosing an MR, improves MR selection
feat: API to choose an MR from a list based on the provided username's involvement as an assignee/reviewer/author

This is a #MINOR release

cmd/app/resolve_discussion.go

@@ -0,0 +1,83 @@
+package app
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/xanzy/go-gitlab"
+)
+
+type DiscussionResolveRequest struct {
+	DiscussionID string `json:"discussion_id"`
+	Resolved     bool   `json:"resolved"`
+}
+
+type DiscussionResolver interface {
+	ResolveMergeRequestDiscussion(pid interface{}, mergeRequest int, discussion string, opt *gitlab.ResolveMergeRequestDiscussionOptions, options ...gitlab.RequestOptionFunc) (*gitlab.Discussion, *gitlab.Response, error)
+}
+
+type discussionsResolutionService struct {
+	data
+	client DiscussionResolver
+}
+
+/* discussionsResolveHandler sets a discussion to be "resolved" or not resolved, depending on the payload */
+func (a discussionsResolutionService) handler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+	if r.Method != http.MethodPut {
+		w.Header().Set("Access-Control-Allow-Methods", http.MethodPut)
+		handleError(w, InvalidRequestError{}, "Expected PUT", http.StatusMethodNotAllowed)
+		return
+	}
+
+	body, err := io.ReadAll(r.Body)
+	if err != nil {
+		handleError(w, err, "Could not read request body", http.StatusBadRequest)
+		return
+	}
+
+	defer r.Body.Close()
+
+	var resolveDiscussionRequest DiscussionResolveRequest
+	err = json.Unmarshal(body, &resolveDiscussionRequest)
+
+	if err != nil {
+		handleError(w, err, "Could not read JSON from request", http.StatusBadRequest)
+		return
+	}
+
+	_, res, err := a.client.ResolveMergeRequestDiscussion(
+		a.projectInfo.ProjectId,
+		a.projectInfo.MergeId,
+		resolveDiscussionRequest.DiscussionID,
+		&gitlab.ResolveMergeRequestDiscussionOptions{Resolved: &resolveDiscussionRequest.Resolved},
+	)
+
+	friendlyName := "unresolve"
+	if resolveDiscussionRequest.Resolved {
+		friendlyName = "resolve"
+	}
+
+	if err != nil {
+		handleError(w, err, fmt.Sprintf("Could not %s discussion", friendlyName), http.StatusInternalServerError)
+		return
+	}
+
+	if res.StatusCode >= 300 {
+		handleError(w, GenericError{endpoint: "/mr/discussions/resolve"}, fmt.Sprintf("Could not %s discussion", friendlyName), res.StatusCode)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+	response := SuccessResponse{
+		Message: fmt.Sprintf("Discussion %sd", friendlyName),
+		Status:  http.StatusOK,
+	}
+
+	err = json.NewEncoder(w).Encode(response)
+	if err != nil {
+		handleError(w, err, "Could not encode response", http.StatusInternalServerError)
+	}
+}