package main_test

import (
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"testing"
)

func TestMakeFat(t *testing.T) {
	if runtime.GOOS != "darwin" {
		t.Skip("works on darwin only")
	}

	// Make a directory to work in.
	dir, err := ioutil.TempDir("", "makefat")
	if err != nil {
		t.Fatalf("could not create directory: %v", err)
	}
	defer os.RemoveAll(dir)

	// List files we're working with.
	src := filepath.Join(dir, "test.go")
	amd64 := filepath.Join(dir, "amd64")
	arm64 := filepath.Join(dir, "arm64")
	fat := filepath.Join(dir, "fat")

	// Create test source.
	f, err := os.Create(src)
	if err != nil {
		t.Fatalf("could not create source file: %v", err)
	}
	f.Write([]byte(`
package main
import "fmt"
func main() {
	fmt.Println("hello world")
}
`))
	f.Close()

	// Compile test code in both amd64 and arm64.
	cmd := exec.Command("go", "build", "-o", amd64, src)
	cmd.Env = append(os.Environ(), "GOARCH=amd64")
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("could not build amd64 target: %v\n%s\n", err, string(out))
	}
	cmd = exec.Command("go", "build", "-o", arm64, src)
	cmd.Env = append(os.Environ(), "GOARCH=arm64")
	out, err = cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("could not build arm64 target: %v\n%s\n", err, string(out))
	}

	// Build fat binary.
	cmd = exec.Command("go", "run", "makefat.go", fat, amd64, arm64)
	out, err = cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("could not build fat target: %v\n%s\n", err, string(out))
	}

	// Run fat binary.
	cmd = exec.Command(fat)
	out, err = cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("could not run fat target: %v", err)
	}
	if string(out) != "hello world\n" {
		t.Errorf("got=%s, want=hello world\n", string(out))
	}
}