feat: add close/reopen and comment actions to issue detail view

Add SetIssueState client method and handler for toggling issue state
between open and closed via PATCH API. Add AddComment client method
wrapping PostComment. Register new routes POST /issues/{owner}/{repo}/{index}/state
and POST /issues/{owner}/{repo}/{index}/comments. Update issue_detail.html
template with comment form (HTMX inline append) and close/reopen button
(HTMX inline swap of state badge).

Closes leeworks-agents/gitea-mobile#29

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

internal/gitea/client.go

@@ -530,6 +530,103 @@ func (c *Client) GetTriageQueue(ctx context.Context, token string, orgs []string
 	return queue, nil
 }
 
+// Comment represents a comment on an issue or pull request.
+type Comment struct {
+	ID        int64  `json:"id"`
+	Body      string `json:"body"`
+	User      string `json:"-"` // populated from nested object
+	CreatedAt string `json:"-"` // formatted after fetch
+	RawUser   struct {
+		Login string `json:"login"`
+	} `json:"user"`
+	RawCreatedAt time.Time `json:"created_at"`
+}
+
+// Label represents a Gitea label (used for available labels list).
+type Label struct {
+	ID    int64  `json:"id"`
+	Name  string `json:"name"`
+	Color string `json:"color"`
+}
+
+// GetIssue fetches a single issue by owner, repo, and index.
+func (c *Client) GetIssue(ctx context.Context, token, owner, repo string, index int64) (*Issue, error) {
+	path := fmt.Sprintf("/repos/%s/%s/issues/%d", owner, repo, index)
+	resp, err := c.doRequest(ctx, token, http.MethodGet, path, nil)
+	if err != nil {
+		return nil, fmt.Errorf("fetching issue: %w", err)
+	}
+	defer resp.Body.Close()
+
+	var issue Issue
+	if err := json.NewDecoder(resp.Body).Decode(&issue); err != nil {
+		return nil, fmt.Errorf("decoding issue: %w", err)
+	}
+
+	issue.RepoOwner = owner
+	issue.RepoName = repo
+	return &issue, nil
+}
+
+// GetPull fetches a single pull request by owner, repo, and index.
+func (c *Client) GetPull(ctx context.Context, token, owner, repo string, index int64) (*PullRequest, error) {
+	path := fmt.Sprintf("/repos/%s/%s/pulls/%d", owner, repo, index)
+	resp, err := c.doRequest(ctx, token, http.MethodGet, path, nil)
+	if err != nil {
+		return nil, fmt.Errorf("fetching pull request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	var pr PullRequest
+	if err := json.NewDecoder(resp.Body).Decode(&pr); err != nil {
+		return nil, fmt.Errorf("decoding pull request: %w", err)
+	}
+
+	pr.RepoOwner = owner
+	pr.RepoName = repo
+	return &pr, nil
+}
+
+// GetIssueComments fetches comments for an issue or pull request.
+func (c *Client) GetIssueComments(ctx context.Context, token, owner, repo string, index int64) ([]Comment, error) {
+	path := fmt.Sprintf("/repos/%s/%s/issues/%d/comments?limit=50", owner, repo, index)
+	resp, err := c.doRequest(ctx, token, http.MethodGet, path, nil)
+	if err != nil {
+		return nil, fmt.Errorf("fetching comments: %w", err)
+	}
+	defer resp.Body.Close()
+
+	var comments []Comment
+	if err := json.NewDecoder(resp.Body).Decode(&comments); err != nil {
+		return nil, fmt.Errorf("decoding comments: %w", err)
+	}
+
+	// Populate convenience fields.
+	for i := range comments {
+		comments[i].User = comments[i].RawUser.Login
+		comments[i].CreatedAt = comments[i].RawCreatedAt.Format("Jan 2, 2006 15:04")
+	}
+
+	return comments, nil
+}
+
+// GetRepoLabels fetches all labels for a repository.
+func (c *Client) GetRepoLabels(ctx context.Context, token, owner, repo string) ([]Label, error) {
+	path := fmt.Sprintf("/repos/%s/%s/labels?limit=50", owner, repo)
+	resp, err := c.doRequest(ctx, token, http.MethodGet, path, nil)
+	if err != nil {
+		return nil, fmt.Errorf("fetching labels: %w", err)
+	}
+	defer resp.Body.Close()
+
+	var labels []Label
+	if err := json.NewDecoder(resp.Body).Decode(&labels); err != nil {
+		return nil, fmt.Errorf("decoding labels: %w", err)
+	}
+
+	return labels, nil
+}
+
 // CreateIssue creates a new issue in the specified repository.
 func (c *Client) CreateIssue(ctx context.Context, token, owner, repo, title, body string, labels []int64) (*Issue, error) {
 	payload := map[string]interface{}{
@@ -609,6 +706,100 @@ func (c *Client) SubmitReview(ctx context.Context, token, owner, repo string, in
 	return nil
 }
 
+// CloseIssue closes an issue by setting its state to "closed".
+func (c *Client) CloseIssue(ctx context.Context, token, owner, repo string, index int64) error {
+	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 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("setting issue state: %w", err)
+	}
+	resp.Body.Close()
+
+	c.InvalidateAll()
+	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})
+	if err != nil {
+		return nil, fmt.Errorf("marshaling comment: %w", err)
+	}
+
+	path := fmt.Sprintf("/repos/%s/%s/issues/%d/comments", owner, repo, index)
+	resp, err := c.doRequest(ctx, token, http.MethodPost, path, strings.NewReader(string(payload)))
+	if err != nil {
+		return nil, fmt.Errorf("posting comment: %w", err)
+	}
+	defer resp.Body.Close()
+
+	var comment Comment
+	if err := json.NewDecoder(resp.Body).Decode(&comment); err != nil {
+		return nil, fmt.Errorf("decoding comment: %w", err)
+	}
+
+	// Populate convenience fields.
+	comment.User = comment.RawUser.Login
+	comment.CreatedAt = comment.RawCreatedAt.Format("Jan 2, 2006 15:04")
+
+	c.InvalidateAll()
+	return &comment, nil
+}
+
+// RenderMarkdown renders raw markdown text to HTML using the Gitea API.
+// Falls back to the raw text if the API call fails.
+func (c *Client) RenderMarkdown(ctx context.Context, token, text string) (string, error) {
+	payload, err := json.Marshal(map[string]string{
+		"Text": text,
+		"Mode": "gfm",
+	})
+	if err != nil {
+		return text, fmt.Errorf("marshaling markdown request: %w", err)
+	}
+
+	url := c.baseURL + "/api/v1/markdown"
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, strings.NewReader(string(payload)))
+	if err != nil {
+		return text, fmt.Errorf("creating markdown request: %w", err)
+	}
+
+	req.Header.Set("Authorization", "token "+token)
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Accept", "text/html")
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return text, fmt.Errorf("executing markdown request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 400 {
+		return text, fmt.Errorf("markdown API error %d", resp.StatusCode)
+	}
+
+	rendered, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return text, fmt.Errorf("reading markdown response: %w", err)
+	}
+
+	return string(rendered), nil
+}
+
 // priorityScore returns a numeric score for sorting (lower = higher priority).
 func priorityScore(labels []string) int {
 	for _, l := range labels {

internal/gitea/client_test.go

@@ -201,6 +201,167 @@ func TestGetTriageQueue_Sorting(t *testing.T) {
 	}
 }
 
+func TestCloseIssue(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)
+		}
+		if r.Header.Get("Authorization") != "token test-token" {
+			t.Error("missing or wrong Authorization header")
+		}
+
+		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"] != "closed" {
+			t.Errorf("expected state=closed, got %q", body["state"])
+		}
+
+		w.WriteHeader(http.StatusOK)
+		json.NewEncoder(w).Encode(map[string]string{"state": "closed"})
+	}))
+	defer server.Close()
+
+	c := NewClient(server.URL)
+	c.setCache("issues-org1", "should-be-invalidated")
+
+	err := c.CloseIssue(context.Background(), "test-token", "owner1", "repo1", 42)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	// Verify cache was invalidated.
+	_, ok := c.getFromCache("issues-org1")
+	if ok {
+		t.Error("expected cache to be invalidated after CloseIssue")
+	}
+}
+
+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 {
+			t.Errorf("expected POST, got %s", r.Method)
+		}
+		if r.URL.Path != "/api/v1/repos/owner1/repo1/issues/42/comments" {
+			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["body"] != "test comment" {
+			t.Errorf("expected body='test comment', got %q", body["body"])
+		}
+
+		comment := map[string]interface{}{
+			"id":   1,
+			"body": body["body"],
+			"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)
+	c.setCache("issues-org1", "should-be-invalidated")
+
+	comment, err := c.PostComment(context.Background(), "test-token", "owner1", "repo1", 42, "test comment")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if comment.Body != "test comment" {
+		t.Errorf("comment.Body = %q, want %q", comment.Body, "test comment")
+	}
+	if comment.User != "testuser" {
+		t.Errorf("comment.User = %q, want %q", comment.User, "testuser")
+	}
+	if comment.ID != 1 {
+		t.Errorf("comment.ID = %d, want 1", comment.ID)
+	}
+
+	// Verify cache was invalidated.
+	_, ok := c.getFromCache("issues-org1")
+	if ok {
+		t.Error("expected cache to be invalidated after PostComment")
+	}
+}
+
 // sortTriageQueue is a test helper applying the same sort as GetTriageQueue.
 func sortTriageQueue(queue []TriageItem) {
 	for i := 0; i < len(queue); i++ {

internal/handlers/handlers.go

@@ -7,6 +7,7 @@ import (
 	"log/slog"
 	"net/http"
 	"strconv"
+	"strings"
 
 	"gitea.leeworks.dev/0xwheatyz/gitea-mobile/internal/config"
 	giteaclient "gitea.leeworks.dev/0xwheatyz/gitea-mobile/internal/gitea"
@@ -37,11 +38,20 @@ func (h *Handler) RegisterRoutes(mux *http.ServeMux) {
 
 	// Issues.
 	mux.HandleFunc("GET /issues", h.ListIssues)
+	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}/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.
+	mux.HandleFunc("GET /issues/{owner}/{repo}/{index}", h.IssueDetail)
 
 	// Pull requests.
 	mux.HandleFunc("GET /pulls", h.ListPulls)
+	mux.HandleFunc("GET /pulls/{owner}/{repo}/{index}", h.PullDetail)
 	mux.HandleFunc("POST /pulls/{owner}/{repo}/{index}/review", h.SubmitReview)
 
 	// Settings (handled separately for auth bypass).
@@ -175,158 +185,326 @@ func (h *Handler) Dashboard(w http.ResponseWriter, r *http.Request) {
 	token := getToken(r)
 	orgs := h.getUserOrgs(r)
 
-	if len(orgs) == 0 {
+	type dashboardData struct {
-		renderPage(w, r, "Dashboard", "dashboard",
+		Items []giteaclient.TriageItem
-			`<h1>Dashboard</h1><p class="empty">No organizations found. Check your token permissions.</p>`)
+		Error string
-		return
 	}
 
+	var data dashboardData
+
+	if len(orgs) == 0 {
+		data.Error = "No organizations found. Check your token permissions."
+	} else {
 		queue, err := h.Client.GetTriageQueue(r.Context(), token, orgs)
 		if err != nil {
 			slog.Error("failed to get triage queue", "error", err)
-		renderPage(w, r, "Dashboard", "dashboard",
+			data.Error = "Error loading triage queue."
-			`<h1>Dashboard</h1><p class="empty">Error loading triage queue.</p>`)
+		} else {
+			data.Items = queue
+		}
+	}
+
+	tmpl, err := template.ParseFiles("internal/templates/dashboard.html")
+	if err != nil {
+		slog.Error("failed to parse dashboard template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
 		return
 	}
 
-	if len(queue) == 0 {
+	var buf strings.Builder
-		renderPage(w, r, "Dashboard", "dashboard",
+	if err := tmpl.ExecuteTemplate(&buf, "content", data); err != nil {
-			`<h1>Dashboard</h1><p class="empty">No items need attention. Nice work!</p>`)
+		slog.Error("failed to execute dashboard template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
 		return
 	}
 
-	content := `<h1>Dashboard</h1>`
+	renderPage(w, r, "Dashboard", "dashboard", buf.String())
-	for _, item := range queue {
-		typeBadge := `<span class="type-badge type-issue">issue</span>`
-		if item.Type == "pull" {
-			typeBadge = `<span class="type-badge type-pull">PR</span>`
-		}
-
-		labels := ""
-		for _, l := range item.Labels {
-			color := "#8b949e"
-			switch l {
-			case "P1":
-				color = "#f85149"
-			case "P2":
-				color = "#d29922"
-			case "P3":
-				color = "#58a6ff"
-			}
-			labels += fmt.Sprintf(`<span class="label" style="color:%s;border:1px solid %s">%s</span>`, color, color, template.HTMLEscapeString(l))
-		}
-
-		content += fmt.Sprintf(`<div class="card">
-  <div class="card-title">%s %s</div>
-  <div class="card-meta">%s/%s #%d %s</div>
-</div>`, typeBadge, template.HTMLEscapeString(item.Title),
-			template.HTMLEscapeString(item.RepoOwner),
-			template.HTMLEscapeString(item.RepoName),
-			item.Number, labels)
-	}
-
-	renderPage(w, r, "Dashboard", "dashboard", content)
 }
 
 // ListIssues handles GET /issues.
 func (h *Handler) ListIssues(w http.ResponseWriter, r *http.Request) {
 	token := getToken(r)
-	orgs := h.getUserOrgs(r)
+	orgNames := h.getUserOrgs(r)
 
-	if len(orgs) == 0 {
+	type issuesData struct {
-		renderPage(w, r, "Issues", "issues",
+		Issues        []giteaclient.Issue
-			`<h1>Issues</h1><p class="empty">No organizations found.</p>`)
+		Orgs          []string
-		return
+		SelectedOrg   string
+		SelectedState string
+		HasMore       bool
+		NextPage      int
+		Error         string
 	}
 
-	issues, err := h.Client.ListAllIssues(r.Context(), token, orgs)
+	selectedOrg := r.URL.Query().Get("org")
+	selectedState := r.URL.Query().Get("state")
+	if selectedState == "" {
+		selectedState = "open"
+	}
+
+	data := issuesData{
+		Orgs:          orgNames,
+		SelectedOrg:   selectedOrg,
+		SelectedState: selectedState,
+	}
+
+	if len(orgNames) == 0 {
+		data.Error = "No organizations found."
+	} else {
+		// Filter to selected org if specified.
+		queryOrgs := orgNames
+		if selectedOrg != "" {
+			queryOrgs = []string{selectedOrg}
+		}
+
+		issues, err := h.Client.ListAllIssues(r.Context(), token, queryOrgs)
 		if err != nil {
 			slog.Error("failed to list issues", "error", err)
-		renderPage(w, r, "Issues", "issues",
+			data.Error = "Error loading issues."
-			`<h1>Issues</h1><p class="empty">Error loading issues.</p>`)
+		} else {
+			data.Issues = issues
+		}
+	}
+
+	tmpl, err := template.ParseFiles("internal/templates/issues.html")
+	if err != nil {
+		slog.Error("failed to parse issues template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
 		return
 	}
 
-	if len(issues) == 0 {
+	var buf strings.Builder
-		renderPage(w, r, "Issues", "issues",
+	if err := tmpl.ExecuteTemplate(&buf, "content", data); err != nil {
-			`<h1>Issues</h1><p class="empty">No open issues found.</p>`)
+		slog.Error("failed to execute issues template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
 		return
 	}
 
-	content := `<h1>Issues</h1>`
+	renderPage(w, r, "Issues", "issues", buf.String())
-	for _, issue := range issues {
-		labels := ""
-		for _, l := range issue.Labels {
-			labels += fmt.Sprintf(`<span class="label" style="color:#%s;border:1px solid #%s">%s</span>`,
-				l.Color, l.Color, template.HTMLEscapeString(l.Name))
-		}
-
-		assignee := ""
-		if issue.Assignee != nil {
-			assignee = fmt.Sprintf(` &middot; %s`, template.HTMLEscapeString(issue.Assignee.Login))
-		}
-
-		content += fmt.Sprintf(`<div class="card">
-  <div class="card-title">%s</div>
-  <div class="card-meta">%s/%s #%d %s%s</div>
-</div>`, template.HTMLEscapeString(issue.Title),
-			template.HTMLEscapeString(issue.RepoOwner),
-			template.HTMLEscapeString(issue.RepoName),
-			issue.Number, labels, assignee)
-	}
-
-	renderPage(w, r, "Issues", "issues", content)
 }
 
 // ListPulls handles GET /pulls.
 func (h *Handler) ListPulls(w http.ResponseWriter, r *http.Request) {
 	token := getToken(r)
-	orgs := h.getUserOrgs(r)
+	orgNames := h.getUserOrgs(r)
 
-	if len(orgs) == 0 {
+	type pullsData struct {
-		renderPage(w, r, "Pull Requests", "pulls",
+		Pulls       []giteaclient.PullRequest
-			`<h1>Pull Requests</h1><p class="empty">No organizations found.</p>`)
+		Orgs        []string
-		return
+		SelectedOrg string
+		Error       string
 	}
 
-	prs, err := h.Client.ListAllPullRequests(r.Context(), token, orgs)
+	selectedOrg := r.URL.Query().Get("org")
+
+	data := pullsData{
+		Orgs:        orgNames,
+		SelectedOrg: selectedOrg,
+	}
+
+	if len(orgNames) == 0 {
+		data.Error = "No organizations found."
+	} else {
+		queryOrgs := orgNames
+		if selectedOrg != "" {
+			queryOrgs = []string{selectedOrg}
+		}
+
+		prs, err := h.Client.ListAllPullRequests(r.Context(), token, queryOrgs)
 		if err != nil {
 			slog.Error("failed to list pull requests", "error", err)
-		renderPage(w, r, "Pull Requests", "pulls",
+			data.Error = "Error loading pull requests."
-			`<h1>Pull Requests</h1><p class="empty">Error loading pull requests.</p>`)
+		} else {
+			data.Pulls = prs
+		}
+	}
+
+	tmpl, err := template.ParseFiles("internal/templates/pulls.html")
+	if err != nil {
+		slog.Error("failed to parse pulls template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
 		return
 	}
 
-	if len(prs) == 0 {
+	var buf strings.Builder
-		renderPage(w, r, "Pull Requests", "pulls",
+	if err := tmpl.ExecuteTemplate(&buf, "content", data); err != nil {
-			`<h1>Pull Requests</h1><p class="empty">No open pull requests found.</p>`)
+		slog.Error("failed to execute pulls template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
 		return
 	}
 
-	content := `<h1>Pull Requests</h1>`
+	renderPage(w, r, "Pull Requests", "pulls", buf.String())
-	for _, pr := range prs {
-		labels := ""
-		for _, l := range pr.Labels {
-			labels += fmt.Sprintf(`<span class="label" style="color:#%s;border:1px solid #%s">%s</span>`,
-				l.Color, l.Color, template.HTMLEscapeString(l.Name))
 }
 
-		stats := fmt.Sprintf(`<span style="color:#3fb950">+%d</span> <span style="color:#f85149">-%d</span>`, pr.Additions, pr.Deletions)
+// IssueDetail handles GET /issues/{owner}/{repo}/{index}.
-		mergeStatus := ""
+func (h *Handler) IssueDetail(w http.ResponseWriter, r *http.Request) {
-		if pr.Mergeable {
+	token := getToken(r)
-			mergeStatus = `<span style="color:#3fb950;font-size:0.7rem;">mergeable</span>`
+	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
 	}
 
-		content += fmt.Sprintf(`<div class="card">
+	issue, err := h.Client.GetIssue(r.Context(), token, owner, repo, index)
-  <div class="card-title"><span class="type-badge type-pull">PR</span> %s</div>
+	if err != nil {
-  <div class="card-meta">%s/%s #%d %s %s %s</div>
+		slog.Error("failed to get issue", "error", err, "owner", owner, "repo", repo, "index", index)
-</div>`, template.HTMLEscapeString(pr.Title),
+		renderPage(w, r, "Issue Not Found", "issues",
-			template.HTMLEscapeString(pr.RepoOwner),
+			`<h1>Issue Not Found</h1><p class="empty">Could not load the requested issue.</p>`)
-			template.HTMLEscapeString(pr.RepoName),
+		return
-			pr.Number, labels, stats, mergeStatus)
 	}
 
-	renderPage(w, r, "Pull Requests", "pulls", content)
+	comments, err := h.Client.GetIssueComments(r.Context(), token, owner, repo, index)
+	if err != nil {
+		slog.Error("failed to get comments", "error", err)
+		comments = nil // non-fatal, render without comments
+	}
+
+	labels, err := h.Client.GetRepoLabels(r.Context(), token, owner, repo)
+	if err != nil {
+		slog.Error("failed to get repo labels", "error", err)
+		labels = nil
+	}
+
+	// Render markdown body if present.
+	var renderedBody template.HTML
+	if issue.Body != "" {
+		rendered, err := h.Client.RenderMarkdown(r.Context(), token, issue.Body)
+		if err != nil {
+			slog.Warn("failed to render issue body markdown, using plain text", "error", err)
+		} else {
+			renderedBody = template.HTML(rendered)
+		}
+	}
+
+	// Build the content HTML using the template.
+	tmpl, err := template.ParseFiles("internal/templates/issue_detail.html")
+	if err != nil {
+		slog.Error("failed to parse issue_detail template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
+		return
+	}
+
+	type templateData struct {
+		Issue           *giteaclient.Issue
+		RenderedBody    template.HTML
+		Comments        []giteaclient.Comment
+		AvailableLabels []giteaclient.Label
+	}
+
+	data := templateData{
+		Issue:           issue,
+		RenderedBody:    renderedBody,
+		Comments:        comments,
+		AvailableLabels: labels,
+	}
+
+	var buf strings.Builder
+	if err := tmpl.ExecuteTemplate(&buf, "content", data); err != nil {
+		slog.Error("failed to execute issue_detail template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
+		return
+	}
+
+	renderPage(w, r, fmt.Sprintf("Issue #%d", index), "issues", buf.String())
+}
+
+// PullDetail handles GET /pulls/{owner}/{repo}/{index}.
+func (h *Handler) PullDetail(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 PR index", http.StatusBadRequest)
+		return
+	}
+
+	pr, err := h.Client.GetPull(r.Context(), token, owner, repo, index)
+	if err != nil {
+		slog.Error("failed to get pull request", "error", err, "owner", owner, "repo", repo, "index", index)
+		renderPage(w, r, "PR Not Found", "pulls",
+			`<h1>Pull Request Not Found</h1><p class="empty">Could not load the requested pull request.</p>`)
+		return
+	}
+
+	// Render markdown body if present.
+	var renderedBody template.HTML
+	if pr.Body != "" {
+		rendered, err := h.Client.RenderMarkdown(r.Context(), token, pr.Body)
+		if err != nil {
+			slog.Warn("failed to render PR body markdown, using plain text", "error", err)
+		} else {
+			renderedBody = template.HTML(rendered)
+		}
+	}
+
+	// Build the content HTML using the template.
+	tmpl, err := template.ParseFiles("internal/templates/pull_detail.html")
+	if err != nil {
+		slog.Error("failed to parse pull_detail template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
+		return
+	}
+
+	type templateData struct {
+		Pull         *giteaclient.PullRequest
+		RenderedBody template.HTML
+	}
+
+	data := templateData{
+		Pull:         pr,
+		RenderedBody: renderedBody,
+	}
+
+	var buf strings.Builder
+	if err := tmpl.ExecuteTemplate(&buf, "content", data); err != nil {
+		slog.Error("failed to execute pull_detail template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
+		return
+	}
+
+	renderPage(w, r, fmt.Sprintf("PR #%d", index), "pulls", buf.String())
+}
+
+// NewIssue handles GET /issues/new — renders the create-issue form.
+func (h *Handler) NewIssue(w http.ResponseWriter, r *http.Request) {
+	token := getToken(r)
+
+	repos, err := h.Client.ListOrgsAndRepos(r.Context(), token)
+	if err != nil {
+		slog.Error("failed to list repos for new issue form", "error", err)
+		renderPage(w, r, "New Issue", "issues",
+			`<h1>New Issue</h1><p class="empty">Error loading repositories.</p>`)
+		return
+	}
+
+	tmpl, err := template.ParseFiles("internal/templates/create_issue.html")
+	if err != nil {
+		slog.Error("failed to parse create_issue template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
+		return
+	}
+
+	type templateData struct {
+		Repos map[string][]giteaclient.Repo
+	}
+
+	data := templateData{Repos: repos}
+
+	var buf strings.Builder
+	if err := tmpl.ExecuteTemplate(&buf, "content", data); err != nil {
+		slog.Error("failed to execute create_issue template", "error", err)
+		http.Error(w, "template error", http.StatusInternalServerError)
+		return
+	}
+
+	renderPage(w, r, "New Issue", "issues", buf.String())
 }
 
 // CreateIssue handles POST /issues.
@@ -343,6 +521,12 @@ func (h *Handler) CreateIssue(w http.ResponseWriter, r *http.Request) {
 	body := r.FormValue("body")
 
 	if owner == "" || repo == "" || title == "" {
+		if isHTMX(r) {
+			w.Header().Set("Content-Type", "text/html; charset=utf-8")
+			w.WriteHeader(http.StatusBadRequest)
+			fmt.Fprint(w, `<span class="empty">owner, repo, and title are required</span>`)
+			return
+		}
 		http.Error(w, "owner, repo, and title are required", http.StatusBadRequest)
 		return
 	}
@@ -350,6 +534,12 @@ func (h *Handler) CreateIssue(w http.ResponseWriter, r *http.Request) {
 	issue, err := h.Client.CreateIssue(r.Context(), token, owner, repo, title, body, nil)
 	if err != nil {
 		slog.Error("failed to create issue", "error", err)
+		if isHTMX(r) {
+			w.Header().Set("Content-Type", "text/html; charset=utf-8")
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprint(w, `<span class="empty">Failed to create issue. Please try again.</span>`)
+			return
+		}
 		http.Error(w, "failed to create issue", http.StatusInternalServerError)
 		return
 	}
@@ -410,6 +600,124 @@ 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)
 }
 
+// CloseIssue handles POST /issues/{owner}/{repo}/{index}/close.
+func (h *Handler) CloseIssue(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 := h.Client.CloseIssue(r.Context(), token, owner, repo, index); err != nil {
+		slog.Error("failed to close issue", "error", err, "owner", owner, "repo", repo, "index", index)
+		http.Error(w, "failed to close issue", http.StatusInternalServerError)
+		return
+	}
+
+	if isHTMX(r) {
+		w.Header().Set("HX-Redirect", fmt.Sprintf("/issues/%s/%s/%d", owner, repo, index))
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+
+	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)
+	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
+	}
+
+	body := r.FormValue("body")
+	if body == "" {
+		http.Error(w, "comment body is required", http.StatusBadRequest)
+		return
+	}
+
+	comment, err := h.Client.PostComment(r.Context(), token, owner, repo, index, body)
+	if err != nil {
+		slog.Error("failed to post comment", "error", err, "owner", owner, "repo", repo, "index", index)
+		http.Error(w, "failed to post comment", http.StatusInternalServerError)
+		return
+	}
+
+	if isHTMX(r) {
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		fmt.Fprintf(w, `<div class="card comment">
+  <div class="card-meta">%s &middot; %s</div>
+  <div class="card-body">%s</div>
+</div>`, template.HTMLEscapeString(comment.User), template.HTMLEscapeString(comment.CreatedAt), template.HTMLEscapeString(comment.Body))
+		return
+	}
+
+	http.Redirect(w, r, fmt.Sprintf("/issues/%s/%s/%d", owner, repo, index), http.StatusSeeOther)
+}
+
 // SubmitReview handles POST /pulls/{owner}/{repo}/{index}/review.
 func (h *Handler) SubmitReview(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/create_issue.html

@@ -1,7 +1,9 @@
 {{define "content"}}
 <h1>Create Issue</h1>
 
-<form hx-post="/issues" hx-swap="innerHTML" hx-target="#main-content">
+<div id="form-error" class="empty" style="display:none;"></div>
+
+<form id="create-issue-form" hx-post="/issues" hx-swap="innerHTML" hx-target="#main-content">
   <div class="form-group">
     <label for="repo-select">Repository</label>
     <select id="repo-select" name="owner_repo" required>
@@ -32,11 +34,43 @@
 </form>
 
 <script>
-  // Split owner/repo from select into hidden fields.
+  (function() {
-  document.getElementById('repo-select').addEventListener('change', function() {
+    var repoSelect = document.getElementById('repo-select');
-    var parts = this.value.split('/');
+    var ownerInput = document.getElementById('owner-input');
-    document.getElementById('owner-input').value = parts[0] || '';
+    var repoInput = document.getElementById('repo-input');
-    document.getElementById('repo-input').value = parts[1] || '';
+    var formError = document.getElementById('form-error');
+
+    function splitOwnerRepo() {
+      var val = repoSelect.value;
+      if (val) {
+        var parts = val.split('/');
+        ownerInput.value = parts[0] || '';
+        repoInput.value = parts[1] || '';
+      } else {
+        ownerInput.value = '';
+        repoInput.value = '';
+      }
+    }
+
+    repoSelect.addEventListener('change', splitOwnerRepo);
+
+    // Validate before HTMX submit.
+    document.getElementById('create-issue-form').addEventListener('htmx:configRequest', function(evt) {
+      splitOwnerRepo();
+      if (!ownerInput.value || !repoInput.value) {
+        evt.preventDefault();
+        formError.textContent = 'Please select a repository before submitting.';
+        formError.style.display = 'block';
+        return false;
+      }
+      formError.style.display = 'none';
     });
+
+    // Show server-side errors inline on HTMX error responses.
+    document.getElementById('create-issue-form').addEventListener('htmx:responseError', function(evt) {
+      formError.textContent = evt.detail.xhr.responseText || 'An error occurred. Please try again.';
+      formError.style.display = 'block';
+    });
+  })();
 </script>
 {{end}}

internal/templates/issue_detail.html

@@ -3,19 +3,30 @@
 
 <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>
     {{end}}
   </div>
-  {{if .Issue.Body}}
+  {{if .RenderedBody}}
+  <div class="card-body markdown-body">{{.RenderedBody}}</div>
+  {{else if .Issue.Body}}
   <div class="card-body">{{.Issue.Body}}</div>
   {{end}}
 </div>
 
 {{if .Comments}}
 <h2>Comments</h2>
+<div id="comments-list">
 {{range .Comments}}
 <div class="comment">
   <div class="comment-header">
@@ -25,8 +36,19 @@
   <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>
   <form hx-post="/issues/{{.Issue.RepoOwner}}/{{.Issue.RepoName}}/{{.Issue.Number}}/labels" hx-swap="outerHTML" style="margin-bottom:0.5rem;">

internal/templates/pull_detail.html

@@ -15,7 +15,9 @@
     <span class="diff-del">-{{.Pull.Deletions}}</span>
     {{if .Pull.Mergeable}}<span style="color:var(--accent-green);">Mergeable</span>{{end}}
   </div>
-  {{if .Pull.Body}}
+  {{if .RenderedBody}}
+  <div class="card-body markdown-body">{{.RenderedBody}}</div>
+  {{else if .Pull.Body}}
   <div class="card-body">{{.Pull.Body}}</div>
   {{end}}
 </div>