// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package reboot_test verifies that the current GOROOT can be used to bootstrap
// itself.
package reboot_test

import (
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"testing"
	"time"
)

func TestRepeatBootstrap(t *testing.T) {
	if testing.Short() {
		t.Skipf("skipping test that rebuilds the entire toolchain")
	}

	realGoroot, err := filepath.Abs(filepath.Join("..", ".."))
	if err != nil {
		t.Fatal(err)
	}

	// To ensure that bootstrapping doesn't unexpectedly depend
	// on the Go repo's git metadata, add a fake (unreadable) git
	// directory above the simulated GOROOT.
	// This mimics the configuration one much have when
	// building from distro-packaged source code
	// (see https://go.dev/issue/54852).
	parent := t.TempDir()
	dotGit := filepath.Join(parent, ".git")
	if err := os.Mkdir(dotGit, 000); err != nil {
		t.Fatal(err)
	}

	overlayStart := time.Now()

	goroot := filepath.Join(parent, "goroot")

	gorootSrc := filepath.Join(goroot, "src")
	if err := overlayDir(gorootSrc, filepath.Join(realGoroot, "src")); err != nil {
		t.Fatal(err)
	}

	gorootLib := filepath.Join(goroot, "lib")
	if err := overlayDir(gorootLib, filepath.Join(realGoroot, "lib")); err != nil {
		t.Fatal(err)
	}

	t.Logf("GOROOT overlay set up in %s", time.Since(overlayStart))

	if err := os.WriteFile(filepath.Join(goroot, "VERSION"), []byte(runtime.Version()), 0666); err != nil {
		t.Fatal(err)
	}

	var makeScript string
	switch runtime.GOOS {
	case "windows":
		makeScript = "make.bat"
	case "plan9":
		makeScript = "make.rc"
	default:
		makeScript = "make.bash"
	}

	var stdout strings.Builder
	cmd := exec.Command(filepath.Join(goroot, "src", makeScript))
	cmd.Dir = gorootSrc
	cmd.Env = append(cmd.Environ(), "GOROOT=", "GOROOT_FINAL=", "GOROOT_BOOTSTRAP="+realGoroot)
	cmd.Stderr = os.Stderr
	cmd.Stdout = io.MultiWriter(os.Stdout, &stdout)
	if err := cmd.Run(); err != nil {
		t.Fatal(err)
	}

	// Test that go.dev/issue/42563 hasn't regressed.
	t.Run("PATH reminder", func(t *testing.T) {
		var want string
		switch gorootBin := filepath.Join(goroot, "bin"); runtime.GOOS {
		default:
			want = fmt.Sprintf("*** You need to add %s to your PATH.", gorootBin)
		case "plan9":
			want = fmt.Sprintf("*** You need to bind %s before /bin.", gorootBin)
		}
		if got := stdout.String(); !strings.Contains(got, want) {
			t.Errorf("reminder %q is missing from %s stdout:\n%s", want, makeScript, got)
		}
	})
}