package migration_01_to_11

import (
	"bytes"
	"fmt"
	"math/rand"
	"time"

	"github.com/btcsuite/btcd/btcec"
	lnwire "github.com/lightningnetwork/lnd/channeldb/migration/lnwire21"
)

var (
	priv, _ = btcec.NewPrivateKey(btcec.S256())
	pub     = priv.PubKey()
)

func makeFakePayment() *outgoingPayment {
	fakeInvoice := &Invoice{
		// Use single second precision to avoid false positive test
		// failures due to the monotonic time component.
		CreationDate:   time.Unix(time.Now().Unix(), 0),
		Memo:           []byte("fake memo"),
		Receipt:        []byte("fake receipt"),
		PaymentRequest: []byte(""),
	}

	copy(fakeInvoice.Terms.PaymentPreimage[:], rev[:])
	fakeInvoice.Terms.Value = lnwire.NewMSatFromSatoshis(10000)

	fakePath := make([][33]byte, 3)
	for i := 0; i < 3; i++ {
		copy(fakePath[i][:], bytes.Repeat([]byte{byte(i)}, 33))
	}

	fakePayment := &outgoingPayment{
		Invoice:        *fakeInvoice,
		Fee:            101,
		Path:           fakePath,
		TimeLockLength: 1000,
	}
	copy(fakePayment.PaymentPreimage[:], rev[:])
	return fakePayment
}

// randomBytes creates random []byte with length in range [minLen, maxLen)
func randomBytes(minLen, maxLen int) ([]byte, error) {
	randBuf := make([]byte, minLen+rand.Intn(maxLen-minLen))

	if _, err := rand.Read(randBuf); err != nil {
		return nil, fmt.Errorf("Internal error. "+
			"Cannot generate random string: %v", err)
	}

	return randBuf, nil
}

func makeRandomFakePayment() (*outgoingPayment, error) {
	var err error
	fakeInvoice := &Invoice{
		// Use single second precision to avoid false positive test
		// failures due to the monotonic time component.
		CreationDate: time.Unix(time.Now().Unix(), 0),
	}

	fakeInvoice.Memo, err = randomBytes(1, 50)
	if err != nil {
		return nil, err
	}

	fakeInvoice.Receipt, err = randomBytes(1, 50)
	if err != nil {
		return nil, err
	}

	fakeInvoice.PaymentRequest, err = randomBytes(1, 50)
	if err != nil {
		return nil, err
	}

	preImg, err := randomBytes(32, 33)
	if err != nil {
		return nil, err
	}
	copy(fakeInvoice.Terms.PaymentPreimage[:], preImg)

	fakeInvoice.Terms.Value = lnwire.MilliSatoshi(rand.Intn(10000))

	fakePathLen := 1 + rand.Intn(5)
	fakePath := make([][33]byte, fakePathLen)
	for i := 0; i < fakePathLen; i++ {
		b, err := randomBytes(33, 34)
		if err != nil {
			return nil, err
		}
		copy(fakePath[i][:], b)
	}

	fakePayment := &outgoingPayment{
		Invoice:        *fakeInvoice,
		Fee:            lnwire.MilliSatoshi(rand.Intn(1001)),
		Path:           fakePath,
		TimeLockLength: uint32(rand.Intn(10000)),
	}
	copy(fakePayment.PaymentPreimage[:], fakeInvoice.Terms.PaymentPreimage[:])

	return fakePayment, nil
}