package streams

import (
	"bytes"
	"io"
	"testing"

	. "github.com/smartystreets/goconvey/convey"
)

func Test_MetadataInjector(t *testing.T) {
	metadata := Metadata{
		"StreamTitle": "Hello",
	}
	metadataLengthByte := (len(metadata.Bytes()) + 15) / 16
	paddedMetadataLength := (metadataLengthByte * 16)
	paddedMetadataBytes := make([]byte, paddedMetadataLength)
	copy(paddedMetadataBytes, metadata.Bytes())

	inputBytes := make([]byte, 1024)
	reader := bytes.NewReader(inputBytes)
	buffer := new(bytes.Buffer)

	Convey("MetadataInjector", t, func() {
		t.Log(len(metadata.Bytes()), "=>", paddedMetadataLength)

		mi := NewMetadataInjector(buffer, 256)
		mi.SetMetadata(metadata)

		// 128
		// 64
		// [metadata]
		// 128
		// 64
		// [metadata]

		n, err := io.Copy(mi, reader)
		So(err, ShouldBeNil)
		So(n, ShouldEqual, len(inputBytes))
		So(buffer.Len(), ShouldEqual, len(inputBytes)+3+paddedMetadataLength)

		outBytes := buffer.Bytes()

		for i := 0; i < 3; i++ {
			t.Log("part", i)

			contentStartOffset := i + i*256
			if i > 0 {
				contentStartOffset += paddedMetadataLength
			}
			t.Log("contentStartOffset", contentStartOffset)

			contentEndOffset := contentStartOffset + 256
			t.Log("contentEndOffset", contentEndOffset)

			metadataEndOffset := contentEndOffset + 1
			if i == 0 {
				metadataEndOffset += paddedMetadataLength
			}
			t.Log("metadataEndOffset", metadataEndOffset)

			So(outBytes[contentStartOffset:contentEndOffset], ShouldResemble, inputBytes[0:256])
			if i == 0 {
				So(outBytes[contentEndOffset], ShouldEqual, metadataLengthByte)
				So(outBytes[contentEndOffset+1:metadataEndOffset], ShouldResemble, paddedMetadataBytes)
			} else {
				So(outBytes[contentEndOffset], ShouldEqual, 0)
			}
		}
	})
}