package testing

import (
	"fmt"
	"os"
	"reflect"
	"runtime"
	"testing"
	"time"

	"github.com/stretchr/testify/require"
)

func AssertErrorInterface(t *testing.T, expected interface{}, actual error, desc string) {
	require.Error(t, actual, desc)
	require.Implements(t, expected, actual, desc)
}

func AssertErrorType(t *testing.T, expected interface{}, actual error, desc string) {
	require.Error(t, actual, desc)
	// require.IsType doesn't take the pointer element, and doesn't resolve
	// through interfaces, so we have to do this one ourselves.
	actualT, expectedT := reflect.TypeOf(actual), reflect.TypeOf(expected).Elem()
	if actualT != expectedT {
		require.FailNow(
			t,
			fmt.Sprintf("Expected %s but got %s", expectedT.String(), actualT.String()),
			desc,
		)
	}
}

func stackTrace(all bool) string {
	buf := make([]byte, 1<<20)
	stacklen := runtime.Stack(buf, all)
	return string(buf[:stacklen])
}

// Borrowed from net/http tests:
// goTimeout runs f, failing t if f takes more than d to complete.
func RunWithTimeout(t *testing.T, d time.Duration, f func()) {
	ch := make(chan bool, 2)
	timer := time.AfterFunc(d, func() {
		t.Errorf("Timeout expired after %v: stacks:\n%s", d, stackTrace(true))
		ch <- true
	})
	defer timer.Stop()
	go func() {
		defer func() { ch <- true }()
		f()
	}()
	<-ch
}

// TrimTestArgs finds the first -- in os.Args and trim all args before that
func TrimTestArgs() {
	i, l := 0, len(os.Args)
	for ; i < l; i++ {
		if os.Args[i] == "--" {
			break
		}
	}
	if i == l {
		panic("Specify weave args after --")
	}
	os.Args = append(os.Args[:1], os.Args[i+1:l]...)
}