package api

import (
	"io/fs"
	"net/http"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"

	"git.georgsen.dk/hwlab/internal/api/handlers"
)

// spaHandler serves static files and falls back to index.html for unknown paths,
// enabling client-side routing in the React SPA.
type spaHandler struct {
	staticFS fs.FS
}

func (h spaHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	// Try to open the requested path in the embedded FS.
	f, err := h.staticFS.Open(r.URL.Path)
	if err != nil {
		// File not found — serve index.html so the SPA router handles it.
		r2 := r.Clone(r.Context())
		r2.URL.Path = "/"
		http.FileServer(http.FS(h.staticFS)).ServeHTTP(w, r2)
		return
	}
	f.Close()
	http.FileServer(http.FS(h.staticFS)).ServeHTTP(w, r)
}

// NewRouter creates the chi router. staticFiles is the fs.FS rooted at web/dist,
// passed from main.go where the go:embed directive lives.
// intakeHandler handles POST /api/intake (multipart photo upload).
func NewRouter(staticFiles fs.FS, intakeHandler http.Handler) http.Handler {
	r := chi.NewRouter()
	r.Use(middleware.Logger)
	r.Use(middleware.Recoverer)
	r.Use(middleware.RealIP)

	r.Route("/api", func(r chi.Router) {
		r.Get("/health", handlers.Health)
		r.Post("/intake", intakeHandler.ServeHTTP)
	})

	// SPA fallback — serve static files; unknown paths fall back to index.html.
	r.Handle("/*", spaHandler{staticFS: staticFiles})

	return r
}