// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: 2023 The Ebitengine Authors

package purego_test

import (
	"os"
	"path/filepath"
	"runtime"
	"testing"

	"github.com/ebitengine/purego"
	"github.com/ebitengine/purego/internal/load"
)

func TestOS(t *testing.T) {
	// set and unset an environment variable since this calls into fakecgo.
	err := os.Setenv("TESTING", "SOMETHING")
	if err != nil {
		t.Errorf("failed to Setenv: %s", err)
	}
	err = os.Unsetenv("TESTING")
	if err != nil {
		t.Errorf("failed to Unsetenv: %s", err)
	}
}

// errnoIsCaptured reports whether SyscallN returns the libc errno as its third
// value on this platform.
func errnoIsCaptured() bool {
	switch runtime.GOOS {
	case "darwin":
		return true
	case "linux":
		switch runtime.GOARCH {
		case "mips", "mipsle", "mips64", "mips64le", "ppc64":
			return true
		}
	}
	return false
}

func TestErrno(t *testing.T) {
	if !errnoIsCaptured() {
		t.Skip("platform does not support returning errno from syscall")
	}

	libFileName := filepath.Join(t.TempDir(), "liberrnotest.so")
	if err := buildSharedLib(t, "CC", libFileName, filepath.Join("testdata", "liberrnotest", "errno_test.c")); err != nil {
		t.Fatal(err)
	}
	defer os.Remove(libFileName)

	lib, err := load.OpenLibrary(libFileName)
	if err != nil {
		t.Fatal(err)
	}

	setErrno, err := load.OpenSymbol(lib, "setErrno")
	if err != nil {
		t.Fatal(err)
	}

	r1, _, errno := purego.SyscallN(setErrno)
	if int32(r1) != -1 {
		t.Errorf("setErrno returned %d, wanted -1", r1)
	}

	libcName, err := getSystemLibrary()
	if err != nil {
		t.Fatal(err)
	}
	libc, err := load.OpenLibrary(libcName)
	if err != nil {
		t.Fatal(err)
	}

	var strerror func(int32) string
	purego.RegisterLibFunc(&strerror, libc, "strerror")

	const expected = "No such file or directory"
	got := strerror(int32(errno))
	if got != expected {
		t.Errorf("strerror returned %q, wanted \"%s\"", got, expected)
	}
}