feat: add Web UI server with basic-auth and artist dashboard

internal/web/handlers.go

@@ -0,0 +1,55 @@
+package web
+
+import (
+	"embed"
+	"fmt"
+	"html/template"
+	"net/http"
+
+	"naviwatcher/internal/config"
+	"naviwatcher/internal/database"
+)
+
+//go:embed templates/*.html
+var templates embed.FS
+
+// dashboardTmpl is parsed once at package init from the embedded templates.
+var dashboardTmpl = template.Must(template.ParseFS(templates, "templates/dashboard.html"))
+
+// handleDashboard renders the artist dashboard: monitored artists with their
+// missing-release counts.
+func (s *Server) handleDashboard(w http.ResponseWriter, r *http.Request) {
+	// Only serve the index at "/" (and not e.g. "/favicon.ico" fallthroughs).
+	if r.URL.Path != "/" {
+		http.NotFound(w, r)
+		return
+	}
+
+	threshold := s.defaultThreshold()
+	data, err := s.buildDashboardData(r.Context(), threshold)
+	if err != nil {
+		http.Error(w, fmt.Sprintf("failed to build dashboard: %v", err), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	if err := dashboardTmpl.Execute(w, data); err != nil {
+		http.Error(w, fmt.Sprintf("template render error: %v", err), http.StatusInternalServerError)
+	}
+}
+
+// defaultThreshold returns the fuzzy threshold to use when scanning for the
+// dashboard. It is currently fixed at the engine default; later wiring can
+// thread the configured threshold through the Server if desired.
+func (s *Server) defaultThreshold() float64 {
+	return 0 // 0 → scanner.DefaultThreshold
+}
+
+// NewServerWithConfig is a convenience constructor that accepts the full
+// *config.Config (mirroring how the app constructs other components). It
+// forwards the server sub-config and derives uiBaseURL from host/port.
+func NewServerWithConfig(cfg *config.Config, db *database.DB) *Server {
+	// Build a best-effort external base URL from the server config.
+	base := fmt.Sprintf("http://%s:%d", cfg.Server.Host, cfg.Server.Port)
+	return NewServer(&cfg.Server, db, base)
+}