feat: add Assign action to issue detail view

Add the ability to assign users to issues from the mobile app:
- New ListCollaborators client method fetches repo collaborators
- New AssignIssue client method sets assignees via PATCH API
- New POST /issues/{owner}/{repo}/{index}/assignees handler
- Assignee dropdown populated with repo collaborators in issue detail
- HTMX inline response confirms assignment without page reload

Closes leeworks-agents/gitea-mobile#50

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/gitea/client.go

@@ -753,6 +753,49 @@ func (c *Client) ApplyLabel(ctx context.Context, token, owner, repo string, inde
 	return nil
 }
 
+// ListCollaborators fetches the list of collaborators (users with access) for a repo.
+func (c *Client) ListCollaborators(ctx context.Context, token, owner, repo string) ([]string, error) {
+	path := fmt.Sprintf("/repos/%s/%s/collaborators?limit=50", owner, repo)
+	resp, err := c.doRequest(ctx, token, http.MethodGet, path, nil)
+	if err != nil {
+		return nil, fmt.Errorf("fetching collaborators: %w", err)
+	}
+	defer resp.Body.Close()
+
+	var users []struct {
+		Login string `json:"login"`
+	}
+	if err := json.NewDecoder(resp.Body).Decode(&users); err != nil {
+		return nil, fmt.Errorf("decoding collaborators: %w", err)
+	}
+
+	var logins []string
+	for _, u := range users {
+		logins = append(logins, u.Login)
+	}
+	return logins, nil
+}
+
+// AssignIssue sets the assignees on an issue.
+func (c *Client) AssignIssue(ctx context.Context, token, owner, repo string, index int64, assignees []string) error {
+	payload, err := json.Marshal(map[string]interface{}{
+		"assignees": assignees,
+	})
+	if err != nil {
+		return fmt.Errorf("marshaling assignees: %w", err)
+	}
+
+	path := fmt.Sprintf("/repos/%s/%s/issues/%d", owner, repo, index)
+	resp, err := c.doRequest(ctx, token, http.MethodPatch, path, strings.NewReader(string(payload)))
+	if err != nil {
+		return fmt.Errorf("assigning issue: %w", err)
+	}
+	resp.Body.Close()
+
+	c.InvalidateAll()
+	return nil
+}
+
 // SubmitReview submits a review on a pull request.
 func (c *Client) SubmitReview(ctx context.Context, token, owner, repo string, index int64, reviewType, body string) error {
 	payload := map[string]interface{}{
@@ -778,15 +821,20 @@ func (c *Client) SubmitReview(ctx context.Context, token, owner, repo string, in
 
 // CloseIssue closes an issue by setting its state to "closed".
 func (c *Client) CloseIssue(ctx context.Context, token, owner, repo string, index int64) error {
-	payload, err := json.Marshal(map[string]string{"state": "closed"})
+	return c.SetIssueState(ctx, token, owner, repo, index, "closed")
+}
+
+// SetIssueState sets an issue's state (e.g. "open" or "closed").
+func (c *Client) SetIssueState(ctx context.Context, token, owner, repo string, index int64, state string) error {
+	payload, err := json.Marshal(map[string]string{"state": state})
 	if err != nil {
-		return fmt.Errorf("marshaling close request: %w", err)
+		return fmt.Errorf("marshaling state change: %w", err)
 	}
 
 	path := fmt.Sprintf("/repos/%s/%s/issues/%d", owner, repo, index)
 	resp, err := c.doRequest(ctx, token, http.MethodPatch, path, strings.NewReader(string(payload)))
 	if err != nil {
-		return fmt.Errorf("closing issue: %w", err)
+		return fmt.Errorf("setting issue state: %w", err)
 	}
 	resp.Body.Close()
 
@@ -794,6 +842,11 @@ func (c *Client) CloseIssue(ctx context.Context, token, owner, repo string, inde
 	return nil
 }
 
+// AddComment creates a comment on an issue and returns the created Comment.
+func (c *Client) AddComment(ctx context.Context, token, owner, repo string, index int64, body string) (*Comment, error) {
+	return c.PostComment(ctx, token, owner, repo, index, body)
+}
+
 // PostComment creates a comment on an issue and returns the created Comment.
 func (c *Client) PostComment(ctx context.Context, token, owner, repo string, index int64, body string) (*Comment, error) {
 	payload, err := json.Marshal(map[string]string{"body": body})

internal/gitea/client_test.go

@@ -241,6 +241,76 @@ func TestCloseIssue(t *testing.T) {
 	}
 }
 
+func TestSetIssueState(t *testing.T) {
+	tests := []struct {
+		name  string
+		state string
+	}{
+		{"close", "closed"},
+		{"reopen", "open"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				if r.Method != http.MethodPatch {
+					t.Errorf("expected PATCH, got %s", r.Method)
+				}
+				if r.URL.Path != "/api/v1/repos/owner1/repo1/issues/42" {
+					t.Errorf("unexpected path: %s", r.URL.Path)
+				}
+
+				var body map[string]string
+				if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+					t.Fatalf("failed to decode body: %v", err)
+				}
+				if body["state"] != tt.state {
+					t.Errorf("expected state=%q, got %q", tt.state, body["state"])
+				}
+
+				w.WriteHeader(http.StatusOK)
+				json.NewEncoder(w).Encode(map[string]string{"state": tt.state})
+			}))
+			defer server.Close()
+
+			c := NewClient(server.URL)
+			c.setCache("issues-org1", "should-be-invalidated")
+
+			err := c.SetIssueState(context.Background(), "test-token", "owner1", "repo1", 42, tt.state)
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+
+			_, ok := c.getFromCache("issues-org1")
+			if ok {
+				t.Error("expected cache to be invalidated after SetIssueState")
+			}
+		})
+	}
+}
+
+func TestAddComment(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		comment := map[string]interface{}{
+			"id":         1,
+			"body":       "test",
+			"user":       map[string]string{"login": "testuser"},
+			"created_at": "2026-03-26T12:00:00Z",
+		}
+		json.NewEncoder(w).Encode(comment)
+	}))
+	defer server.Close()
+
+	c := NewClient(server.URL)
+	comment, err := c.AddComment(context.Background(), "test-token", "owner1", "repo1", 42, "test")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if comment.Body != "test" {
+		t.Errorf("comment.Body = %q, want %q", comment.Body, "test")
+	}
+}
+
 func TestPostComment(t *testing.T) {
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != http.MethodPost {

internal/handlers/handlers.go

@@ -41,7 +41,10 @@ func (h *Handler) RegisterRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("GET /issues/new", h.NewIssue)
 	mux.HandleFunc("POST /issues", h.CreateIssue)
 	mux.HandleFunc("POST /issues/{owner}/{repo}/{index}/labels", h.ApplyLabels)
+	mux.HandleFunc("POST /issues/{owner}/{repo}/{index}/assignees", h.AssignIssue)
 	mux.HandleFunc("POST /issues/{owner}/{repo}/{index}/close", h.CloseIssue)
+	mux.HandleFunc("POST /issues/{owner}/{repo}/{index}/state", h.SetIssueState)
+	mux.HandleFunc("POST /issues/{owner}/{repo}/{index}/comments", h.AddComment)
 	mux.HandleFunc("POST /issues/{owner}/{repo}/{index}/comment", h.AddComment)
 
 	// Issue detail.
@@ -115,6 +118,10 @@ var basePage = template.Must(template.New("base").Parse(`<!DOCTYPE html>
   <script src="/static/htmx.min.js"></script>
 </head>
 <body>
+  <header class="top-bar">
+    <span class="top-bar-title">Gitea Mobile</span>
+    <button class="refresh-btn" hx-get="" hx-target="#main-content" hx-swap="innerHTML" aria-label="Refresh">&#8635;</button>
+  </header>
   <div class="content" id="main-content">
     {{.Content}}
   </div>
@@ -423,6 +430,12 @@ func (h *Handler) IssueDetail(w http.ResponseWriter, r *http.Request) {
 		labels = nil
 	}
 
+	collaborators, err := h.Client.ListCollaborators(r.Context(), token, owner, repo)
+	if err != nil {
+		slog.Error("failed to get collaborators", "error", err)
+		collaborators = nil
+	}
+
 	// Render markdown body if present.
 	var renderedBody template.HTML
 	if issue.Body != "" {
@@ -447,6 +460,7 @@ func (h *Handler) IssueDetail(w http.ResponseWriter, r *http.Request) {
 		RenderedBody    template.HTML
 		Comments        []giteaclient.Comment
 		AvailableLabels []giteaclient.Label
+		Collaborators   []string
 	}
 
 	data := templateData{
@@ -454,6 +468,7 @@ func (h *Handler) IssueDetail(w http.ResponseWriter, r *http.Request) {
 		RenderedBody:    renderedBody,
 		Comments:        comments,
 		AvailableLabels: labels,
+		Collaborators:   collaborators,
 	}
 
 	var buf strings.Builder
@@ -654,6 +669,45 @@ func (h *Handler) ApplyLabels(w http.ResponseWriter, r *http.Request) {
 	http.Redirect(w, r, fmt.Sprintf("/issues/%s/%s/%d", owner, repo, index), http.StatusSeeOther)
 }
 
+// AssignIssue handles POST /issues/{owner}/{repo}/{index}/assignees.
+func (h *Handler) AssignIssue(w http.ResponseWriter, r *http.Request) {
+	token := getToken(r)
+	owner := r.PathValue("owner")
+	repo := r.PathValue("repo")
+	indexStr := r.PathValue("index")
+
+	index, err := strconv.ParseInt(indexStr, 10, 64)
+	if err != nil {
+		http.Error(w, "invalid issue index", http.StatusBadRequest)
+		return
+	}
+
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "bad request", http.StatusBadRequest)
+		return
+	}
+
+	assignee := r.FormValue("assignee")
+	if assignee == "" {
+		http.Error(w, "assignee is required", http.StatusBadRequest)
+		return
+	}
+
+	if err := h.Client.AssignIssue(r.Context(), token, owner, repo, index, []string{assignee}); err != nil {
+		slog.Error("failed to assign issue", "error", err, "owner", owner, "repo", repo, "index", index, "assignee", assignee)
+		http.Error(w, "failed to assign issue", http.StatusInternalServerError)
+		return
+	}
+
+	if isHTMX(r) {
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		fmt.Fprintf(w, `<span style="color:#3fb950">Assigned to %s</span>`, template.HTMLEscapeString(assignee))
+		return
+	}
+
+	http.Redirect(w, r, fmt.Sprintf("/issues/%s/%s/%d", owner, repo, index), http.StatusSeeOther)
+}
+
 // CloseIssue handles POST /issues/{owner}/{repo}/{index}/close.
 func (h *Handler) CloseIssue(w http.ResponseWriter, r *http.Request) {
 	token := getToken(r)
@@ -682,6 +736,53 @@ func (h *Handler) CloseIssue(w http.ResponseWriter, r *http.Request) {
 	http.Redirect(w, r, fmt.Sprintf("/issues/%s/%s/%d", owner, repo, index), http.StatusSeeOther)
 }
 
+// SetIssueState handles POST /issues/{owner}/{repo}/{index}/state.
+func (h *Handler) SetIssueState(w http.ResponseWriter, r *http.Request) {
+	token := getToken(r)
+	owner := r.PathValue("owner")
+	repo := r.PathValue("repo")
+	indexStr := r.PathValue("index")
+
+	index, err := strconv.ParseInt(indexStr, 10, 64)
+	if err != nil {
+		http.Error(w, "invalid issue index", http.StatusBadRequest)
+		return
+	}
+
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "bad request", http.StatusBadRequest)
+		return
+	}
+
+	state := r.FormValue("state")
+	if state != "open" && state != "closed" {
+		http.Error(w, "state must be 'open' or 'closed'", http.StatusBadRequest)
+		return
+	}
+
+	if err := h.Client.SetIssueState(r.Context(), token, owner, repo, index, state); err != nil {
+		slog.Error("failed to set issue state", "error", err, "owner", owner, "repo", repo, "index", index, "state", state)
+		http.Error(w, "failed to update issue state", http.StatusInternalServerError)
+		return
+	}
+
+	if isHTMX(r) {
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		if state == "closed" {
+			fmt.Fprintf(w, `<span class="state-closed" id="issue-state">closed</span>
+<button class="btn btn-secondary" hx-post="/issues/%s/%s/%d/state" hx-vals='{"state":"open"}' hx-target="#state-section" hx-swap="innerHTML">Reopen Issue</button>`,
+				template.HTMLEscapeString(owner), template.HTMLEscapeString(repo), index)
+		} else {
+			fmt.Fprintf(w, `<span class="state-open" id="issue-state">open</span>
+<button class="btn btn-danger" hx-post="/issues/%s/%s/%d/state" hx-vals='{"state":"closed"}' hx-target="#state-section" hx-swap="innerHTML">Close Issue</button>`,
+				template.HTMLEscapeString(owner), template.HTMLEscapeString(repo), index)
+		}
+		return
+	}
+
+	http.Redirect(w, r, fmt.Sprintf("/issues/%s/%s/%d", owner, repo, index), http.StatusSeeOther)
+}
+
 // AddComment handles POST /issues/{owner}/{repo}/{index}/comment.
 func (h *Handler) AddComment(w http.ResponseWriter, r *http.Request) {
 	token := getToken(r)

internal/handlers/handlers_test.go

@@ -135,6 +135,54 @@ func TestSubmitReview_MissingEventType(t *testing.T) {
 	}
 }
 
+func TestSetIssueState_InvalidState(t *testing.T) {
+	h := newTestHandler()
+	mux := http.NewServeMux()
+	mux.HandleFunc("POST /issues/{owner}/{repo}/{index}/state", h.SetIssueState)
+
+	req := httptest.NewRequest(http.MethodPost, "/issues/org/repo/1/state", nil)
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	w := httptest.NewRecorder()
+
+	mux.ServeHTTP(w, req)
+
+	if w.Code != http.StatusBadRequest {
+		t.Errorf("status = %d, want %d", w.Code, http.StatusBadRequest)
+	}
+}
+
+func TestSetIssueState_InvalidIndex(t *testing.T) {
+	h := newTestHandler()
+	mux := http.NewServeMux()
+	mux.HandleFunc("POST /issues/{owner}/{repo}/{index}/state", h.SetIssueState)
+
+	req := httptest.NewRequest(http.MethodPost, "/issues/org/repo/abc/state", nil)
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	w := httptest.NewRecorder()
+
+	mux.ServeHTTP(w, req)
+
+	if w.Code != http.StatusBadRequest {
+		t.Errorf("status = %d, want %d", w.Code, http.StatusBadRequest)
+	}
+}
+
+func TestAddComment_EmptyBody(t *testing.T) {
+	h := newTestHandler()
+	mux := http.NewServeMux()
+	mux.HandleFunc("POST /issues/{owner}/{repo}/{index}/comments", h.AddComment)
+
+	req := httptest.NewRequest(http.MethodPost, "/issues/org/repo/1/comments", nil)
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	w := httptest.NewRecorder()
+
+	mux.ServeHTTP(w, req)
+
+	if w.Code != http.StatusBadRequest {
+		t.Errorf("status = %d, want %d", w.Code, http.StatusBadRequest)
+	}
+}
+
 func contains(s, substr string) bool {
 	return len(s) >= len(substr) && searchString(s, substr)
 }

internal/templates/issue_detail.html

@@ -3,7 +3,15 @@
 
 <div class="card">
   <div class="card-meta">
-    <span class="state-open">{{.Issue.State}}</span>
+    <span id="state-section">
+      {{if eq .Issue.State "closed"}}
+      <span class="state-closed" id="issue-state">{{.Issue.State}}</span>
+      <button class="btn btn-secondary" hx-post="/issues/{{.Issue.RepoOwner}}/{{.Issue.RepoName}}/{{.Issue.Number}}/state" hx-vals='{"state":"open"}' hx-target="#state-section" hx-swap="innerHTML">Reopen Issue</button>
+      {{else}}
+      <span class="state-open" id="issue-state">{{.Issue.State}}</span>
+      <button class="btn btn-danger" hx-post="/issues/{{.Issue.RepoOwner}}/{{.Issue.RepoName}}/{{.Issue.Number}}/state" hx-vals='{"state":"closed"}' hx-target="#state-section" hx-swap="innerHTML">Close Issue</button>
+      {{end}}
+    </span>
     <span>{{.Issue.RepoOwner}}/{{.Issue.RepoName}} #{{.Issue.Number}}</span>
     {{range .Issue.Labels}}
     <span class="label" style="color:#{{.Color}};border:1px solid #{{.Color}}">{{.Name}}</span>
@@ -18,6 +26,7 @@
 
 {{if .Comments}}
 <h2>Comments</h2>
+<div id="comments-list">
 {{range .Comments}}
 <div class="comment">
   <div class="comment-header">
@@ -27,10 +36,33 @@
   <div class="comment-body">{{.Body}}</div>
 </div>
 {{end}}
+</div>
+{{else}}
+<div id="comments-list"></div>
 {{end}}
 
+<div class="card" style="margin-top:1rem;">
+  <h2>Add Comment</h2>
+  <form hx-post="/issues/{{.Issue.RepoOwner}}/{{.Issue.RepoName}}/{{.Issue.Number}}/comments" hx-target="#comments-list" hx-swap="beforeend" hx-on::after-request="if(event.detail.successful) this.reset()">
+    <textarea name="body" rows="4" placeholder="Write a comment..." required style="width:100%;margin-bottom:0.5rem;"></textarea>
+    <button type="submit" class="btn btn-primary" style="width:auto;padding:0.5rem 1rem;">Comment</button>
+  </form>
+</div>
+
 <div class="card" style="margin-top:1rem;">
   <h2>Actions</h2>
+  {{if .Collaborators}}
+  <form hx-post="/issues/{{.Issue.RepoOwner}}/{{.Issue.RepoName}}/{{.Issue.Number}}/assignees" hx-swap="outerHTML" style="margin-bottom:0.5rem;">
+    <div class="filter-bar" style="margin-bottom:0.5rem;">
+      <select name="assignee">
+        {{range .Collaborators}}
+        <option value="{{.}}">{{.}}</option>
+        {{end}}
+      </select>
+      <button type="submit" class="btn btn-secondary" style="width:auto;padding:0.5rem 1rem;">Assign</button>
+    </div>
+  </form>
+  {{end}}
   <form hx-post="/issues/{{.Issue.RepoOwner}}/{{.Issue.RepoName}}/{{.Issue.Number}}/labels" hx-swap="outerHTML" style="margin-bottom:0.5rem;">
     <div class="filter-bar" style="margin-bottom:0.5rem;">
       <select name="label_id">

internal/templates/layout.html

@@ -13,6 +13,10 @@
   <script src="/static/htmx.min.js"></script>
 </head>
 <body>
+  <header class="top-bar">
+    <span class="top-bar-title">Gitea Mobile</span>
+    <button class="refresh-btn" hx-get="" hx-target="#main-content" hx-swap="innerHTML" aria-label="Refresh">&#8635;</button>
+  </header>
   <div class="content" id="main-content">
     {{template "content" .}}
   </div>

static/style.css

@@ -47,10 +47,53 @@ body {
   -moz-osx-font-smoothing: grayscale;
 }
 
+/* Top bar */
+.top-bar {
+  position: sticky;
+  top: 0;
+  z-index: 100;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: var(--spacing-sm) var(--spacing-lg);
+  padding-top: max(var(--spacing-sm), env(safe-area-inset-top));
+  background: var(--bg-secondary);
+  border-bottom: 1px solid var(--border);
+}
+
+.top-bar-title {
+  font-size: var(--font-base);
+  font-weight: 600;
+  color: var(--text-primary);
+}
+
+.refresh-btn {
+  background: none;
+  border: none;
+  color: var(--text-secondary);
+  font-size: 1.4rem;
+  padding: var(--spacing-xs) var(--spacing-sm);
+  cursor: pointer;
+  -webkit-tap-highlight-color: transparent;
+  line-height: 1;
+  border-radius: var(--radius-sm);
+  transition: color 0.15s ease, background 0.15s ease;
+}
+
+.refresh-btn:active {
+  color: var(--accent-blue);
+  background: var(--bg-tertiary);
+}
+
+.refresh-btn.htmx-request {
+  animation: spin 0.6s linear infinite;
+  pointer-events: none;
+}
+
 /* Content area */
 .content {
   padding: var(--spacing-lg);
-  padding-top: max(var(--spacing-lg), env(safe-area-inset-top));
+  padding-top: var(--spacing-lg);
   max-width: 640px;
   margin: 0 auto;
 }