appview: state: add RepoCompare{,Diff} handlers

appview/pages/pages.go

···
 	return p.executePlain("repo/pulls/fragments/pullNewComment", w, params)
 }
 
+type RepoCompareParams struct {
+	LoggedInUser *oauth.User
+	RepoInfo     repoinfo.RepoInfo
+	Forks        []db.Repo
+	Branches     []types.Branch
+	Tags         []*types.TagReference
+
+	Active string
+}
+
+func (p *Pages) RepoCompare(w io.Writer, params RepoCompareParams) error {
+	params.Active = "overview"
+	return p.executeRepo("repo/compare/new", w, params)
+}
+
+type RepoCompareDiffParams struct {
+	LoggedInUser *oauth.User
+	RepoInfo     repoinfo.RepoInfo
+	FormatPatch  types.RepoFormatPatchResponse
+
+	Active string
+}
+
+func (p *Pages) RepoCompareDiff(w io.Writer, params RepoCompareDiffParams) error {
+	params.Active = "overview"
+	return p.executeRepo("repo/compare/new", w, params)
+}
+
 func (p *Pages) Static() http.Handler {
 	if p.dev {
 		return http.StripPrefix("/static/", http.FileServer(http.Dir("appview/pages/static")))

appview/pages/templates/repo/compare/new.html

···
+{{ define "title" }}new comparison{{ end }}
+
+{{ define "repoContent" }}
+    <h2 class="font-bold text-sm mb-4 uppercase dark:text-white">
+        Compare changes
+    </h2>
+    <p>Choose any two refs to compare.</p>
+
+    <div class="flex items-center gap-2 py-4">
+        <div>
+            base:
+            <select
+                class="p-1 border max-w-32 border-gray-200 bg-white dark:bg-gray-800 dark:text-white dark:border-gray-700"
+            >
+                <optgroup
+                    label="branches ({{ len .Branches }})"
+                    class="bold text-sm"
+                >
+                    {{ range .Branches }}
+                        <option
+                            value="{{ .Reference.Name }}"
+                            class="py-1"
+                            {{ if .IsDefault }}
+                                selected
+                            {{ end }}
+                        >
+                            {{ .Reference.Name }}
+                        </option>
+                    {{ end }}
+                </optgroup>
+                <optgroup label="tags ({{ len .Tags }})" class="bold text-sm">
+                    {{ range .Tags }}
+                        <option value="{{ .Reference.Name }}" class="py-1">
+                            {{ .Reference.Name }}
+                        </option>
+                    {{ else }}
+                        <option class="py-1" disabled>no tags found</option>
+                    {{ end }}
+                </optgroup>
+            </select>
+        </div>
+        {{ i "arrow-left" "w-4 h-4" }}
+        <div>
+            compare:
+            <select
+                class="p-1 border max-w-32 border-gray-200 bg-white dark:bg-gray-800 dark:text-white dark:border-gray-700"
+            >
+                <optgroup
+                    label="branches ({{ len .Branches }})"
+                    class="bold text-sm"
+                >
+                    {{ range .Branches }}
+                        <option value="{{ .Reference.Name }}" class="py-1">
+                            {{ .Reference.Name }}
+                        </option>
+                    {{ end }}
+                </optgroup>
+                <optgroup label="tags ({{ len .Tags }})" class="bold text-sm">
+                    {{ range .Tags }}
+                        <option value="{{ .Reference.Name }}" class="py-1">
+                            {{ .Reference.Name }}
+                        </option>
+                    {{ else }}
+                        <option class="py-1" disabled>no tags found</option>
+                    {{ end }}
+                </optgroup>
+            </select>
+        </div>
+    </div>
+{{ end }}
+
+{{ define "repoAfter" }}
+    <div id="compare-diff"></div>
+{{ end }}

appview/state/repo.go

···
 		return
 	}
 }
+
+func (s *State) RepoCompare(w http.ResponseWriter, r *http.Request) {
+	user := s.oauth.GetUser(r)
+	f, err := s.fullyResolvedRepo(r)
+	if err != nil {
+		log.Println("failed to get repo and knot", err)
+		return
+	}
+
+	us, err := knotclient.NewUnsignedClient(f.Knot, s.config.Core.Dev)
+	if err != nil {
+		log.Printf("failed to create unsigned client for %s", f.Knot)
+		s.pages.Error503(w)
+		return
+	}
+
+	branches, err := us.Branches(f.OwnerDid(), f.RepoName)
+	if err != nil {
+		s.pages.Notice(w, "compare-error", "Failed to produce comparison. Try again later.")
+		log.Println("failed to reach knotserver", err)
+		return
+	}
+
+	tags, err := us.Tags(f.OwnerDid(), f.RepoName)
+	if err != nil {
+		s.pages.Notice(w, "compare-error", "Failed to produce comparison. Try again later.")
+		log.Println("failed to reach knotserver", err)
+		return
+	}
+
+	forks, err := db.GetForksByDid(s.db, user.Did)
+	if err != nil {
+		s.pages.Notice(w, "compare-error", "Failed to produce comparison. Try again later.")
+		log.Println("failed to get forks", err)
+		return
+	}
+
+	s.pages.RepoCompare(w, pages.RepoCompareParams{
+		LoggedInUser: user,
+		RepoInfo:     f.RepoInfo(s, user),
+		Forks:        forks,
+		Branches:     branches.Branches,
+		Tags:         tags.Tags,
+	})
+}
+
+func (s *State) RepoCompareDiff(w http.ResponseWriter, r *http.Request) {
+	f, err := s.fullyResolvedRepo(r)
+	if err != nil {
+		log.Println("failed to get repo and knot", err)
+		return
+	}
+	user := s.oauth.GetUser(r)
+
+	rest := chi.URLParam(r, "*") // master...feature/xyz
+	parts := strings.SplitN(rest, "...", 2)
+	if len(parts) != 2 {
+		s.pages.Notice(w, "compare-error", "Invalid ref format.")
+		return
+	}
+
+	ref1 := parts[0]
+	ref2 := parts[1]
+
+	us, err := knotclient.NewUnsignedClient(f.Knot, s.config.Core.Dev)
+	if err != nil {
+		s.pages.Notice(w, "compare-error", "Failed to produce comparison. Try again later.")
+		log.Println("failed to reach knotserver", err)
+		return
+	}
+
+	formatPatch, err := us.Compare(f.OwnerDid(), f.RepoName, ref1, ref2)
+	if err != nil {
+		s.pages.Notice(w, "compare-error", "Failed to produce comparison. Try again later.")
+		log.Println("failed to compare", err)
+		return
+	}
+
+	s.pages.RepoCompareDiff(w, pages.RepoCompareDiffParams{
+		LoggedInUser: user,
+		RepoInfo:     f.RepoInfo(s, user),
+		FormatPatch:  *formatPatch,
+	})
+}

appview/state/router.go

···
 				})
 			})
 
+			r.Route("/compare", func(r chi.Router) {
+				r.Get("/", s.RepoCompare)
+
+				// we have to wildcard here since we want to support GitHub's compare syntax
+				//   /compare/{ref1}...{ref2}
+				// for example:
+				//   /compare/master...some/feature
+				//   /compare/master...example.com:another/feature <- this is a fork
+				r.Get("/*", s.RepoCompareDiff)
+			})
+
 			r.Route("/pulls", func(r chi.Router) {
 				r.Get("/", s.RepoPulls)
 				r.With(middleware.AuthMiddleware(s.oauth)).Route("/new", func(r chi.Router) {