feat: MVP phase 1 complete

internal/web/render.go

@@ -0,0 +1,74 @@
+package web
+
+import (
+	"embed"
+	"fmt"
+	"html/template"
+	"net/http"
+	"strings"
+	"time"
+)
+
+//go:embed templates
+var templateFS embed.FS
+
+var funcMap = template.FuncMap{
+	"upper":      strings.ToUpper,
+	"lower":      strings.ToLower,
+	"formatDate": func(t time.Time) string { return t.Format("2006-01-02") },
+	"formatTime": func(t time.Time) string { return t.Format("2006-01-02 15:04") },
+	"ago": func(t time.Time) string {
+		d := time.Since(t)
+		switch {
+		case d < time.Minute:
+			return "just now"
+		case d < time.Hour:
+			return fmt.Sprintf("%dm ago", int(d.Minutes()))
+		case d < 24*time.Hour:
+			return fmt.Sprintf("%dh ago", int(d.Hours()))
+		default:
+			return fmt.Sprintf("%dd ago", int(d.Hours()/24))
+		}
+	},
+	"pct": func(f float64) string { return fmt.Sprintf("%.2f%%", f) },
+}
+
+// parse returns a template set containing base.html and the named page.
+// Parsing per-request ensures each page's {{define "content"}} is isolated.
+func parse(name string) (*template.Template, error) {
+	return template.New("").Funcs(funcMap).ParseFS(templateFS, "templates/base.html", "templates/"+name)
+}
+
+type pageData struct {
+	Title    string
+	Username string
+	IsAdmin  bool
+	Flash    string
+	Path     string
+	Data     any
+}
+
+func render(w http.ResponseWriter, r *http.Request, name string, title string, data any) {
+	pd := pageData{
+		Title: title,
+		Path:  r.URL.Path,
+		Data:  data,
+	}
+	// Inject client info from context if present.
+	if c := clientFromCtx(r); c != nil {
+		pd.Username = c.DisplayName
+		pd.IsAdmin = c.IsAdmin
+	}
+	// Flash message from query param (redirect-after-post pattern).
+	pd.Flash = r.URL.Query().Get("flash")
+
+	t, err := parse(name)
+	if err != nil {
+		http.Error(w, "template error: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	if err := t.ExecuteTemplate(w, "base", pd); err != nil {
+		http.Error(w, "template error: "+err.Error(), http.StatusInternalServerError)
+	}
+}