1 files changed, 476 insertions, 0 deletions
diff --git a/internal/admin/server.go b/internal/admin/server.go
new file mode 100644
index 0000000..858d498
--- /dev/null
+++ b/internal/admin/server.go
@@ -0,0 +1,476 @@
+// Package admin provides an HTTP server for managing posts via a web UI.
+// Admin pages are served dynamically and are never written to the static
+// output directory — they are intentionally excluded from the site generator.
+package admin
+
+import (
+	"fmt"
+	"html/template"
+	"net/http"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"time"
+
+	"nebbet.no/internal/auth"
+	"nebbet.no/internal/builder"
+)
+
+// Server is an http.Handler that serves the admin post-management UI.
+type Server struct {
+	// PostsDir is the directory where post markdown files are stored,
+	// e.g. "content/posts". It is created on first use if it doesn't exist.
+	PostsDir string
+	// AuthFile is the path to the htpasswd-compatible passwords file.
+	// Authentication is skipped when AuthFile is empty or the file doesn't exist.
+	AuthFile string
+	// Builder is used to rebuild pages after create/edit/delete operations.
+	Builder *builder.Builder
+
+	tmpl *template.Template
+}
+
+// post holds the metadata and content of a single post.
+type post struct {
+	Slug    string
+	Title   string
+	Date    string
+	Tags    string // comma-separated
+	Content string // raw markdown body
+}
+
+// ServeHTTP implements http.Handler. Expected to be mounted with a stripped
+// prefix, e.g.: http.StripPrefix("/admin", srv)
+func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if !s.checkAuth(w, r) {
+		return
+	}
+
+	if s.tmpl == nil {
+		s.tmpl = mustParseTemplates()
+	}
+
+	path := strings.TrimRight(r.URL.Path, "/")
+
+	switch {
+	case path == "" || path == "/":
+		s.handleList(w, r)
+	case path == "/new":
+		s.handleNew(w, r)
+	case strings.HasSuffix(path, "/edit"):
+		slug := strings.TrimPrefix(strings.TrimSuffix(path, "/edit"), "/")
+		s.handleEdit(w, r, slug)
+	case strings.HasSuffix(path, "/delete"):
+		slug := strings.TrimPrefix(strings.TrimSuffix(path, "/delete"), "/")
+		s.handleDelete(w, r, slug)
+	default:
+		http.NotFound(w, r)
+	}
+}
+
+// checkAuth performs HTTP Basic authentication against the passwords file.
+// Returns true if the request is authorised (or if auth is disabled).
+func (s *Server) checkAuth(w http.ResponseWriter, r *http.Request) bool {
+	if s.AuthFile == "" {
+		return true
+	}
+	if _, err := os.Stat(s.AuthFile); os.IsNotExist(err) {
+		return true // no passwords file → no auth required
+	}
+	a := auth.New(s.AuthFile)
+	username, password, ok := r.BasicAuth()
+	if ok {
+		if valid, err := a.Verify(username, password); err == nil && valid {
+			return true
+		}
+	}
+	w.Header().Set("WWW-Authenticate", `Basic realm="Admin"`)
+	http.Error(w, "Unauthorised", http.StatusUnauthorized)
+	return false
+}
+
+// ── Handlers ─────────────────────────────────────────────────────────────────
+
+func (s *Server) handleList(w http.ResponseWriter, r *http.Request) {
+	posts, err := s.listPosts()
+	if err != nil {
+		http.Error(w, "Failed to list posts: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+	s.render(w, "list", map[string]any{"Posts": posts})
+}
+
+func (s *Server) handleNew(w http.ResponseWriter, r *http.Request) {
+	if r.Method == http.MethodPost {
+		s.handleNewPost(w, r)
+		return
+	}
+	s.render(w, "form", map[string]any{
+		"Title":   "New Post",
+		"Action":  "/admin/new",
+		"Post":    post{Date: time.Now().Format("2006-01-02")},
+		"IsNew":   true,
+	})
+}
+
+func (s *Server) handleNewPost(w http.ResponseWriter, r *http.Request) {
+	p := postFromForm(r)
+	if p.Title == "" {
+		s.renderError(w, "Title is required")
+		return
+	}
+	if p.Slug == "" {
+		p.Slug = slugify(p.Title)
+	}
+
+	mdPath := filepath.Join(s.PostsDir, p.Slug+".md")
+	if err := os.MkdirAll(s.PostsDir, 0755); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	if _, err := os.Stat(mdPath); err == nil {
+		s.renderError(w, fmt.Sprintf("Post %q already exists", p.Slug))
+		return
+	}
+	if err := writePostFile(mdPath, p); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	s.rebuild(mdPath)
+	http.Redirect(w, r, "/admin/", http.StatusSeeOther)
+}
+
+func (s *Server) handleEdit(w http.ResponseWriter, r *http.Request, slug string) {
+	mdPath := filepath.Join(s.PostsDir, slug+".md")
+	p, err := readPostFile(mdPath, slug)
+	if err != nil {
+		http.NotFound(w, r)
+		return
+	}
+	if r.Method == http.MethodPost {
+		updated := postFromForm(r)
+		updated.Slug = slug // slug is immutable after creation
+		if updated.Title == "" {
+			s.renderError(w, "Title is required")
+			return
+		}
+		if err := writePostFile(mdPath, updated); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		s.rebuild(mdPath)
+		http.Redirect(w, r, "/admin/", http.StatusSeeOther)
+		return
+	}
+	s.render(w, "form", map[string]any{
+		"Title":  "Edit Post",
+		"Action": "/admin/" + slug + "/edit",
+		"Post":   p,
+		"IsNew":  false,
+	})
+}
+
+func (s *Server) handleDelete(w http.ResponseWriter, r *http.Request, slug string) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	mdPath := filepath.Join(s.PostsDir, slug+".md")
+	if err := os.Remove(mdPath); err != nil && !os.IsNotExist(err) {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	if s.Builder != nil {
+		_ = s.Builder.RemovePage(mdPath)
+	}
+	http.Redirect(w, r, "/admin/", http.StatusSeeOther)
+}
+
+// ── Helpers ───────────────────────────────────────────────────────────────────
+
+func (s *Server) rebuild(mdPath string) {
+	if s.Builder == nil {
+		return
+	}
+	importMap, _ := builder.GenerateImportMap(s.Builder.LibDir)
+	_ = s.Builder.BuildFile(mdPath, importMap)
+}
+
+func (s *Server) listPosts() ([]post, error) {
+	if err := os.MkdirAll(s.PostsDir, 0755); err != nil {
+		return nil, err
+	}
+	entries, err := os.ReadDir(s.PostsDir)
+	if err != nil {
+		return nil, err
+	}
+	var posts []post
+	for _, e := range entries {
+		if e.IsDir() || !strings.HasSuffix(e.Name(), ".md") {
+			continue
+		}
+		slug := strings.TrimSuffix(e.Name(), ".md")
+		p, err := readPostFile(filepath.Join(s.PostsDir, e.Name()), slug)
+		if err == nil {
+			posts = append(posts, p)
+		}
+	}
+	return posts, nil
+}
+
+func (s *Server) render(w http.ResponseWriter, name string, data map[string]any) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	if err := s.tmpl.ExecuteTemplate(w, name, data); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+}
+
+func (s *Server) renderError(w http.ResponseWriter, msg string) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	w.WriteHeader(http.StatusBadRequest)
+	_ = s.tmpl.ExecuteTemplate(w, "error", map[string]any{"Message": msg})
+}
+
+// postFromForm reads a post from an HTTP form submission.
+func postFromForm(r *http.Request) post {
+	_ = r.ParseForm()
+	return post{
+		Title:   strings.TrimSpace(r.FormValue("title")),
+		Date:    strings.TrimSpace(r.FormValue("date")),
+		Tags:    strings.TrimSpace(r.FormValue("tags")),
+		Content: r.FormValue("content"),
+	}
+}
+
+// readPostFile reads and parses a markdown file into a post struct.
+func readPostFile(path, slug string) (post, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return post{}, err
+	}
+	p := post{Slug: slug}
+	body := string(data)
+
+	// Parse frontmatter manually — keep it simple.
+	if strings.HasPrefix(body, "---\n") {
+		end := strings.Index(body[4:], "\n---\n")
+		if end >= 0 {
+			fm := body[4 : end+4]
+			p.Content = strings.TrimSpace(body[end+9:])
+			for _, line := range strings.Split(fm, "\n") {
+				k, v, ok := strings.Cut(line, ":")
+				if !ok {
+					continue
+				}
+				k = strings.TrimSpace(k)
+				v = strings.TrimSpace(v)
+				switch k {
+				case "title":
+					p.Title = v
+				case "date":
+					p.Date = v
+				case "tags":
+					p.Tags = v
+				}
+			}
+		}
+	} else {
+		p.Content = body
+	}
+	return p, nil
+}
+
+// writePostFile writes a post to disk as a markdown file with frontmatter.
+func writePostFile(path string, p post) error {
+	date := p.Date
+	if date == "" {
+		date = time.Now().Format("2006-01-02")
+	}
+	content := fmt.Sprintf("---\ntitle: %s\ndate: %s\ntags: %s\n---\n%s\n",
+		p.Title, date, p.Tags, p.Content)
+	return os.WriteFile(path, []byte(content), 0644)
+}
+
+// slugify converts a title to a URL-safe slug.
+var nonAlnum = regexp.MustCompile(`[^a-z0-9]+`)
+
+func slugify(title string) string {
+	s := strings.ToLower(title)
+	s = nonAlnum.ReplaceAllString(s, "-")
+	s = strings.Trim(s, "-")
+	if s == "" {
+		s = fmt.Sprintf("post-%d", time.Now().Unix())
+	}
+	return s
+}
+
+// ── Templates ─────────────────────────────────────────────────────────────────
+
+const adminCSS = `
+* { box-sizing: border-box; margin: 0; padding: 0; }
+body { font-family: system-ui, sans-serif; background: #f5f5f5; color: #222; }
+.layout { max-width: 960px; margin: 0 auto; padding: 1.5rem 1rem; }
+nav { display: flex; align-items: center; gap: 1.5rem; padding: 0.75rem 0;
+      border-bottom: 1px solid #ddd; margin-bottom: 2rem; }
+nav a { text-decoration: none; color: #555; font-size: 0.9rem; }
+nav a:hover { color: #000; }
+nav .brand { font-weight: 700; color: #000; font-size: 1rem; }
+h1 { font-size: 1.4rem; margin-bottom: 1.25rem; }
+h2 { font-size: 1.1rem; margin-bottom: 0.75rem; }
+table { width: 100%; border-collapse: collapse; background: #fff;
+        border-radius: 6px; overflow: hidden; box-shadow: 0 1px 3px rgba(0,0,0,.08); }
+th { background: #f0f0f0; font-size: 0.8rem; text-transform: uppercase;
+     letter-spacing: .04em; color: #666; padding: 0.6rem 0.9rem; text-align: left; }
+td { padding: 0.7rem 0.9rem; border-top: 1px solid #eee; vertical-align: middle; }
+tr:hover td { background: #fafafa; }
+.tags { display: flex; flex-wrap: wrap; gap: 0.3rem; }
+.tag { background: #e8f0fe; color: #2d5fc4; font-size: 0.75rem;
+       padding: 0.1rem 0.45rem; border-radius: 3px; }
+.actions { display: flex; gap: 0.5rem; }
+a.btn, button.btn { display: inline-block; padding: 0.35rem 0.75rem; font-size: 0.82rem;
+  border: none; border-radius: 4px; cursor: pointer; text-decoration: none;
+  font-family: inherit; }
+.btn-primary { background: #2d5fc4; color: #fff; }
+.btn-primary:hover { background: #1e4bad; }
+.btn-secondary { background: #e0e0e0; color: #333; }
+.btn-secondary:hover { background: #ccc; }
+.btn-danger { background: #dc2626; color: #fff; }
+.btn-danger:hover { background: #b91c1c; }
+.empty { text-align: center; padding: 3rem; color: #999; font-size: 0.9rem; }
+form { background: #fff; padding: 1.5rem; border-radius: 6px;
+       box-shadow: 0 1px 3px rgba(0,0,0,.08); max-width: 760px; }
+label { display: block; font-size: 0.85rem; font-weight: 600;
+        color: #444; margin-bottom: 0.3rem; margin-top: 1rem; }
+label:first-child { margin-top: 0; }
+input[type=text], input[type=date], textarea {
+  width: 100%; padding: 0.5rem 0.65rem; border: 1px solid #ccc;
+  border-radius: 4px; font-size: 0.9rem; font-family: inherit; }
+input[type=text]:focus, input[type=date]:focus, textarea:focus {
+  outline: none; border-color: #2d5fc4; box-shadow: 0 0 0 2px rgba(45,95,196,.15); }
+textarea { font-family: 'Menlo', 'Consolas', monospace; font-size: 0.85rem;
+           height: 340px; resize: vertical; line-height: 1.5; }
+.hint { font-size: 0.75rem; color: #888; margin-top: 0.25rem; }
+.form-actions { display: flex; gap: 0.75rem; margin-top: 1.5rem; }
+.alert { background: #fef2f2; border: 1px solid #fca5a5; color: #991b1b;
+         padding: 0.75rem 1rem; border-radius: 4px; margin-bottom: 1rem; }
+`
+
+const baseTemplate = `<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <title>Admin — {{.Title}}</title>
+  <style>` + adminCSS + `</style>
+</head>
+<body>
+<div class="layout">
+  <nav>
+    <span class="brand">Admin</span>
+    <a href="/admin/">Posts</a>
+    <a href="/admin/new">New Post</a>
+  </nav>
+  {{block "content" .}}{{end}}
+</div>
+</body>
+</html>`
+
+const listTemplate = `{{define "list"}}` + baseTemplate + `{{end}}
+{{define "content"}}
+  <h1>Posts</h1>
+  {{if .Posts}}
+  <table>
+    <thead>
+      <tr>
+        <th>Title</th>
+        <th>Date</th>
+        <th>Tags</th>
+        <th></th>
+      </tr>
+    </thead>
+    <tbody>
+      {{range .Posts}}
+      <tr>
+        <td>{{.Title}}</td>
+        <td>{{.Date}}</td>
+        <td>
+          {{if .Tags}}
+          <div class="tags">
+            {{range (splitTags .Tags)}}<span class="tag">{{.}}</span>{{end}}
+          </div>
+          {{end}}
+        </td>
+        <td>
+          <div class="actions">
+            <a href="/admin/{{.Slug}}/edit" class="btn btn-secondary">Edit</a>
+            <form method="POST" action="/admin/{{.Slug}}/delete"
+                  onsubmit="return confirm('Delete {{.Title}}?')">
+              <button type="submit" class="btn btn-danger">Delete</button>
+            </form>
+          </div>
+        </td>
+      </tr>
+      {{end}}
+    </tbody>
+  </table>
+  {{else}}
+  <div class="empty">No posts yet. <a href="/admin/new">Create one.</a></div>
+  {{end}}
+{{end}}`
+
+const formTemplate = `{{define "form"}}` + baseTemplate + `{{end}}
+{{define "content"}}
+  <h1>{{.Title}}</h1>
+  <form method="POST" action="{{.Action}}">
+    <label for="title">Title</label>
+    <input type="text" id="title" name="title" value="{{.Post.Title}}" required autofocus>
+
+    <label for="date">Date</label>
+    <input type="date" id="date" name="date" value="{{.Post.Date}}">
+
+    <label for="tags">Tags</label>
+    <input type="text" id="tags" name="tags" value="{{.Post.Tags}}"
+           placeholder="tag1, tag2, tag3">
+    <p class="hint">Comma-separated list of tags.</p>
+
+    <label for="content">Content (Markdown)</label>
+    <textarea id="content" name="content">{{.Post.Content}}</textarea>
+
+    <div class="form-actions">
+      <button type="submit" class="btn btn-primary">
+        {{if .IsNew}}Create Post{{else}}Save Changes{{end}}
+      </button>
+      <a href="/admin/" class="btn btn-secondary">Cancel</a>
+    </div>
+  </form>
+{{end}}`
+
+const errorTemplate = `{{define "error"}}<!DOCTYPE html>
+<html><head><meta charset="UTF-8"><title>Error</title>
+<style>body{font-family:system-ui;max-width:600px;margin:3rem auto;padding:0 1rem}</style>
+</head><body>
+<h2>Error</h2>
+<p>{{.Message}}</p>
+<p><a href="javascript:history.back()">Go back</a></p>
+</body></html>{{end}}`
+
+func mustParseTemplates() *template.Template {
+	funcs := template.FuncMap{
+		"splitTags": func(s string) []string {
+			var tags []string
+			for _, t := range strings.Split(s, ",") {
+				t = strings.TrimSpace(t)
+				if t != "" {
+					tags = append(tags, t)
+				}
+			}
+			return tags
+		},
+	}
+	return template.Must(
+		template.New("admin").Funcs(funcs).Parse(
+			listTemplate + formTemplate + errorTemplate,
+		),
+	)
+}