package main

import (
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func TestIconFromDir(t *testing.T) {
	dir := t.TempDir()
	png := []byte{0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0, 1, 2, 3}
	if e := os.WriteFile(filepath.Join(dir, "favicon.png"), png, 0644); e != nil {
		t.Fatal(e)
	}
	u := iconFromDir(dir)
	if !strings.HasPrefix(u, "data:image/png;base64,") {
		t.Fatalf("got %q", u)
	}
}

func TestIconFromPortFavicon(t *testing.T) {
	ico := []byte{0, 0, 1, 0, 1, 0, 16, 16, 0, 0, 1, 0, 32, 0}
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/favicon.ico" {
			w.Header().Set("Content-Type", "image/x-icon")
			_, _ = w.Write(ico)
			return
		}
		http.NotFound(w, r)
	}))
	defer srv.Close()
	// iconFromPort 用 127.0.0.1:port，从 httptest URL 解析端口
	u := srv.URL
	port := 0
	if i := strings.LastIndex(u, ":"); i >= 0 {
		_, _ = fmtSscanf(u[i+1:], &port)
	}
	if port == 0 {
		t.Fatal("no port")
	}
	got := iconFromPort(port)
	if !strings.HasPrefix(got, "data:image/") {
		t.Fatalf("got %q", got)
	}
}

func fmtSscanf(s string, port *int) (int, error) {
	n := 0
	for _, c := range s {
		if c < '0' || c > '9' {
			break
		}
		n = n*10 + int(c-'0')
	}
	*port = n
	return 1, nil
}