package erasureencode

import (
	// "fmt"
	"bytes"
	"io"
	"testing"
)

var simpleDecodeMeta = &EEMeta{
	Params: Params{
		Size:   0,
		Stride: 2,
		Shards: 3,
		Parity: 2,
	},
}

func TestDecode_EvenStride_Full(t *testing.T) {
	expected := []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11}
	simpleDecodeMeta.Params.Size = int64(len(expected))

	inputs := []io.ReadSeeker{
		bytes.NewReader([]byte{0x00, 0x01, 0x06, 0x07, 0x0c, 0x0d}),
		bytes.NewReader([]byte{0x02, 0x03, 0x08, 0x09, 0x0e, 0x0f}),
		bytes.NewReader([]byte{0x04, 0x05, 0x0a, 0x0b, 0x10, 0x11}),
	}

	output := &bytes.Buffer{}
	if err := Decode(inputs, output, simpleDecodeMeta); err != nil {
		t.Errorf(`Error: %s`, err)
	}

	actual := output.Bytes()
	if !bytes.Equal(actual, expected) {
		t.Errorf(`Expected %x to equal %x`, actual, expected)
	}
}

func TestDecode_EvenStride_Short1(t *testing.T) {
	expected := []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10}
	simpleDecodeMeta.Params.Size = int64(len(expected))

	inputs := []io.ReadSeeker{
		bytes.NewReader([]byte{0x00, 0x01, 0x06, 0x07, 0x0c, 0x0d}),
		bytes.NewReader([]byte{0x02, 0x03, 0x08, 0x09, 0x0e, 0x0f}),
		bytes.NewReader([]byte{0x04, 0x05, 0x0a, 0x0b, 0x10, 0x00}),
	}

	output := &bytes.Buffer{}
	if err := Decode(inputs, output, simpleDecodeMeta); err != nil {
		t.Errorf(`Error: %s`, err)
	}

	actual := output.Bytes()
	if !bytes.Equal(actual, expected) {
		t.Errorf(`Expected %x to equal %x`, actual, expected)
	}
}

func TestDecode_EvenStride_Short2(t *testing.T) {
	expected := []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f}
	simpleDecodeMeta.Params.Size = int64(len(expected))

	inputs := []io.ReadSeeker{
		bytes.NewReader([]byte{0x00, 0x01, 0x06, 0x07, 0x0c, 0x0d}),
		bytes.NewReader([]byte{0x02, 0x03, 0x08, 0x09, 0x0e, 0x0f}),
		bytes.NewReader([]byte{0x04, 0x05, 0x0a, 0x0b, 0x00, 0x00}),
	}

	output := &bytes.Buffer{}
	if err := Decode(inputs, output, simpleDecodeMeta); err != nil {
		t.Errorf(`Error: %s`, err)
	}

	actual := output.Bytes()
	if !bytes.Equal(actual, expected) {
		t.Errorf(`Expected %x to equal %x`, actual, expected)
	}
}

func TestDecode_OddStride_Full(t *testing.T) {
	expected := []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e}
	simpleDecodeMeta.Params.Size = int64(len(expected))

	inputs := []io.ReadSeeker{
		bytes.NewReader([]byte{0x00, 0x01, 0x06, 0x07, 0x0c}),
		bytes.NewReader([]byte{0x02, 0x03, 0x08, 0x09, 0x0d}),
		bytes.NewReader([]byte{0x04, 0x05, 0x0a, 0x0b, 0x0e}),
	}

	output := &bytes.Buffer{}
	if err := Decode(inputs, output, simpleDecodeMeta); err != nil {
		t.Errorf(`Error: %s`, err)
	}

	actual := output.Bytes()
	if !bytes.Equal(actual, expected) {
		t.Errorf(`Expected %x to equal %x`, actual, expected)
	}
}

func TestDecode_OddStride_Short1(t *testing.T) {
	expected := []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d}
	simpleDecodeMeta.Params.Size = int64(len(expected))

	inputs := []io.ReadSeeker{
		bytes.NewReader([]byte{0x00, 0x01, 0x06, 0x07, 0x0c}),
		bytes.NewReader([]byte{0x02, 0x03, 0x08, 0x09, 0x0d}),
		bytes.NewReader([]byte{0x04, 0x05, 0x0a, 0x0b, 0x00}),
	}

	output := &bytes.Buffer{}
	if err := Decode(inputs, output, simpleDecodeMeta); err != nil {
		t.Errorf(`Error: %s`, err)
	}

	actual := output.Bytes()
	if !bytes.Equal(actual, expected) {
		t.Errorf(`Expected %x to equal %x`, actual, expected)
	}
}

func TestDecode_OddStride_Short2(t *testing.T) {
	expected := []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c}
	simpleDecodeMeta.Params.Size = int64(len(expected))

	inputs := []io.ReadSeeker{
		bytes.NewReader([]byte{0x00, 0x01, 0x06, 0x07, 0x0c}),
		bytes.NewReader([]byte{0x02, 0x03, 0x08, 0x09, 0x00}),
		bytes.NewReader([]byte{0x04, 0x05, 0x0a, 0x0b, 0x00}),
	}

	output := &bytes.Buffer{}
	if err := Decode(inputs, output, simpleDecodeMeta); err != nil {
		t.Errorf(`Error: %s`, err)
	}

	actual := output.Bytes()
	if !bytes.Equal(actual, expected) {
		t.Errorf(`Expected %x to equal %x`, actual, expected)
	}
}