//go:build embedspa

// spa_embed.go — serves the Vite-built SPA embedded into the binary. Built only
// with `-tags embedspa` (after `npm --prefix ui ci && npm --prefix ui run build`),
// so the default `go build`/`go test` don't require ui/dist (a build artifact).
// The Dockerfile builds the SPA then compiles with this tag.
package main

import (
	"embed"
	"io/fs"
	"net/http"
	"strings"
)

//go:embed all:ui/dist
var spaFiles embed.FS

func (s *server) spaHandler() http.Handler {
	sub, err := fs.Sub(spaFiles, "ui/dist")
	if err != nil {
		panic(err)
	}
	files := http.FileServer(http.FS(sub))
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p := strings.TrimPrefix(r.URL.Path, "/")
		if p == "" {
			p = "index.html"
		}
		// Real asset -> serve it; anything else -> SPA entry (hash routing).
		if _, err := fs.Stat(sub, p); err != nil {
			http.ServeFileFS(w, r, sub, "index.html")
			return
		}
		files.ServeHTTP(w, r)
	})
}