package util

import (
	"os"
	"path"
	"testing"

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

func TestReadFileLimit(t *testing.T) {
	dir := t.TempDir()
	require.NoError(t, os.WriteFile(path.Join(dir, "file"), []byte("123456"), 0o600))

	_, err := ReadFile(t.Context(), dir, ReadRequest{Filename: "file"}, 4)
	require.ErrorContains(t, err, "file exceeds maximum allowed size of 4 bytes")

	dt, err := ReadFile(t.Context(), dir, ReadRequest{
		Filename: "file",
		Range:    &FileRange{Length: 5},
	}, 4)
	require.NoError(t, err)
	require.Equal(t, []byte("12345"), dt)

	_, err = ReadFile(t.Context(), dir, ReadRequest{
		Filename: "file",
		Range:    &FileRange{Length: 6},
	}, 4)
	require.ErrorContains(t, err, "file exceeds maximum allowed size of 4 bytes")

	dt, err = ReadFile(t.Context(), dir, ReadRequest{
		Filename: "file",
		Range:    &FileRange{Offset: 3, Length: 100},
	}, 4)
	require.NoError(t, err)
	require.Equal(t, []byte("456"), dt)
}

// TestSetErrorPath ensures that modifying the os.PathError from fsutil.Stat
// modifies the error message appropriately.
//
// This method of modifying the path error is an implementation
// detail of how the error is returned. It isn't necessarily the
// case that this will always work if the underlying library changes.
func TestSetErrorPath(t *testing.T) {
	// Temporary directory to reduce the chance of using stat on a real file.
	dir := t.TempDir()

	// Random path that shouldn't exist.
	fpath := path.Join(dir, "a/b/c")
	_, err := fsutil.Stat(fpath)
	require.Error(t, err)

	require.ErrorContains(t, err, "a/b/c")
	// Set the path in the error to a new path.
	replaceErrorPath(err, "/my/new/path")
	require.NotContains(t, err.Error(), "a/b/c")
	require.Contains(t, err.Error(), "/my/new/path")
}