package avro

import (
	"bytes"
	"testing"

	"github.com/linkedin/goavro/v2"
)

func TestBytesOverwrite(t *testing.T) {
	schema := `
{
  "name":"example",
  "type":"record",
  "fields":[
    {"name":"foo","type":"bytes"},
    {"name":"bar","type":"bytes"}
  ]
}`

	codec, err := goavro.NewCodec(schema)
	if err != nil {
		t.Fatal(err)
	}

	// binary data contains {foo:[1,2],bar:[3,4]}
	binary := []byte{4, 1, 2, 4, 3, 4}
	gotNative, _, err := codec.NativeFromBinary(binary)
	if err != nil {
		t.Fatal(err)
	}

	got := gotNative.(map[string]interface{})
	foo := got["foo"].([]byte)
	bar := got["bar"].([]byte)

	if want := []byte{1, 2}; !bytes.Equal(foo, want) {
		t.Fatalf("expected foo to be %v, actually got %v", want, foo)
	}
	if want := []byte{3, 4}; !bytes.Equal(bar, want) {
		t.Fatalf("expected bar to be %v, actually got %v", want, bar)
	}

	// because slices use the same underlying array we can overwrite the others
	// by appending to foo
	foo = append(foo, 0, 0)

	if want := []byte{1, 2, 0, 0}; !bytes.Equal(foo, want) {
		t.Fatalf("expected foo to be %v, actually got %v", want, foo)
	}
	if want := []byte{3, 4}; !bytes.Equal(bar, want) {
		// this assertion fails, bar was changed to [0, 4]
		t.Errorf("expected bar to be %v, actually got %v", want, bar)
	}
	if want := []byte{4, 1, 2, 4, 3, 4}; !bytes.Equal(binary, want) {
		// this assertion fails, binary was changed to [4, 1, 2, 0, 0, 4]
		t.Errorf("expected binary to be %v, actually got %v", want, binary)
	}
}