package channeldb

import (
	"crypto/rand"
	"crypto/sha256"
	"reflect"
	"testing"
	"time"

	"github.com/davecgh/go-spew/spew"
	"github.com/lightningnetwork/lnd/lnwire"
)

func randInvoice(value lnwire.MilliSatoshi) (*Invoice, error) {
	var pre [32]byte
	if _, err := rand.Read(pre[:]); err != nil {
		return nil, err
	}

	i := &Invoice{
		// Use single second precision to avoid false positive test
		// failures due to the monotonic time component.
		CreationDate: time.Unix(time.Now().Unix(), 0),
		Terms: ContractTerm{
			PaymentPreimage: pre,
			Value:           value,
		},
	}
	i.Memo = []byte("memo")
	i.Receipt = []byte("receipt")

	// Create a random byte slice of MaxPaymentRequestSize bytes to be used
	// as a dummy paymentrequest, and  determine if it should be set based
	// on one of the random bytes.
	var r [MaxPaymentRequestSize]byte
	if _, err := rand.Read(r[:]); err != nil {
		return nil, err
	}
	if r[0]&1 == 0 {
		i.PaymentRequest = r[:]
	} else {
		i.PaymentRequest = []byte("")
	}

	return i, nil
}

func TestInvoiceWorkflow(t *testing.T) {
	t.Parallel()

	db, cleanUp, err := makeTestDB()
	defer cleanUp()
	if err != nil {
		t.Fatalf("unable to make test db: %v", err)
	}

	// Create a fake invoice which we'll use several times in the tests
	// below.
	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 = []byte("memo")
	fakeInvoice.Receipt = []byte("receipt")
	fakeInvoice.PaymentRequest = []byte("")
	copy(fakeInvoice.Terms.PaymentPreimage[:], rev[:])
	fakeInvoice.Terms.Value = lnwire.NewMSatFromSatoshis(10000)

	// Add the invoice to the database, this should succeed as there aren't
	// any existing invoices within the database with the same payment
	// hash.
	if _, err := db.AddInvoice(fakeInvoice); err != nil {
		t.Fatalf("unable to find invoice: %v", err)
	}

	// Attempt to retrieve the invoice which was just added to the
	// database. It should be found, and the invoice returned should be
	// identical to the one created above.
	paymentHash := sha256.Sum256(fakeInvoice.Terms.PaymentPreimage[:])
	dbInvoice, err := db.LookupInvoice(paymentHash)
	if err != nil {
		t.Fatalf("unable to find invoice: %v", err)
	}
	if !reflect.DeepEqual(*fakeInvoice, dbInvoice) {
		t.Fatalf("invoice fetched from db doesn't match original %v vs %v",
			spew.Sdump(fakeInvoice), spew.Sdump(dbInvoice))
	}

	// The add index of the invoice retrieved from the database should now
	// be fully populated. As this is the first index written to the DB,
	// the addIndex should be 1.
	if dbInvoice.AddIndex != 1 {
		t.Fatalf("wrong add index: expected %v, got %v", 1,
			dbInvoice.AddIndex)
	}

	// Settle the invoice, the version retrieved from the database should
	// now have the settled bit toggle to true and a non-default
	// SettledDate
	payAmt := fakeInvoice.Terms.Value * 2
	if _, err := db.SettleInvoice(paymentHash, payAmt); err != nil {
		t.Fatalf("unable to settle invoice: %v", err)
	}
	dbInvoice2, err := db.LookupInvoice(paymentHash)
	if err != nil {
		t.Fatalf("unable to fetch invoice: %v", err)
	}
	if !dbInvoice2.Terms.Settled {
		t.Fatalf("invoice should now be settled but isn't")
	}
	if dbInvoice2.SettleDate.IsZero() {
		t.Fatalf("invoice should have non-zero SettledDate but isn't")
	}

	// Our 2x payment should be reflected, and also the settle index of 1
	// should also have been committed for this index.
	if dbInvoice2.AmtPaid != payAmt {
		t.Fatalf("wrong amt paid: expected %v, got %v", payAmt,
			dbInvoice2.AmtPaid)
	}
	if dbInvoice2.SettleIndex != 1 {
		t.Fatalf("wrong settle index: expected %v, got %v", 1,
			dbInvoice2.SettleIndex)
	}

	// Attempt to insert generated above again, this should fail as
	// duplicates are rejected by the processing logic.
	if _, err := db.AddInvoice(fakeInvoice); err != ErrDuplicateInvoice {
		t.Fatalf("invoice insertion should fail due to duplication, "+
			"instead %v", err)
	}

	// Attempt to look up a non-existent invoice, this should also fail but
	// with a "not found" error.
	var fakeHash [32]byte
	if _, err := db.LookupInvoice(fakeHash); err != ErrInvoiceNotFound {
		t.Fatalf("lookup should have failed, instead %v", err)
	}

	// Add 10 random invoices.
	const numInvoices = 10
	amt := lnwire.NewMSatFromSatoshis(1000)
	invoices := make([]*Invoice, numInvoices+1)
	invoices[0] = &dbInvoice2
	for i := 1; i < len(invoices)-1; i++ {
		invoice, err := randInvoice(amt)
		if err != nil {
			t.Fatalf("unable to create invoice: %v", err)
		}

		if _, err := db.AddInvoice(invoice); err != nil {
			t.Fatalf("unable to add invoice %v", err)
		}

		invoices[i] = invoice
	}

	// Perform a scan to collect all the active invoices.
	dbInvoices, err := db.FetchAllInvoices(false)
	if err != nil {
		t.Fatalf("unable to fetch all invoices: %v", err)
	}

	// The retrieve list of invoices should be identical as since we're
	// using big endian, the invoices should be retrieved in ascending
	// order (and the primary key should be incremented with each
	// insertion).
	for i := 0; i < len(invoices)-1; i++ {
		if !reflect.DeepEqual(*invoices[i], dbInvoices[i]) {
			t.Fatalf("retrieved invoices don't match %v vs %v",
				spew.Sdump(invoices[i]),
				spew.Sdump(dbInvoices[i]))
		}
	}
}

// TestInvoiceTimeSeries tests that newly added invoices invoices, as well as
// settled invoices are added to the database are properly placed in the add
// add or settle index which serves as an event time series.
func TestInvoiceAddTimeSeries(t *testing.T) {
	t.Parallel()

	db, cleanUp, err := makeTestDB()
	defer cleanUp()
	if err != nil {
		t.Fatalf("unable to make test db: %v", err)
	}

	// We'll start off by creating 20 random invoices, and inserting them
	// into the database.
	const numInvoices = 20
	amt := lnwire.NewMSatFromSatoshis(1000)
	invoices := make([]Invoice, numInvoices)
	for i := 0; i < len(invoices); i++ {
		invoice, err := randInvoice(amt)
		if err != nil {
			t.Fatalf("unable to create invoice: %v", err)
		}

		if _, err := db.AddInvoice(invoice); err != nil {
			t.Fatalf("unable to add invoice %v", err)
		}

		invoices[i] = *invoice
	}

	// With the invoices constructed, we'll now create a series of queries
	// that we'll use to assert expected return values of
	// InvoicesAddedSince.
	addQueries := []struct {
		sinceAddIndex uint64

		resp []Invoice
	}{
		// If we specify a value of zero, we shouldn't get any invoices
		// back.
		{
			sinceAddIndex: 0,
		},

		// If we specify a value well beyond the number of inserted
		// invoices, we shouldn't get any invoices back.
		{
			sinceAddIndex: 99999999,
		},

		// Using an index of 1 should result in all values, but the
		// first one being returned.
		{
			sinceAddIndex: 1,
			resp:          invoices[1:],
		},

		// If we use an index of 10, then we should retrieve the
		// reaming 10 invoices.
		{
			sinceAddIndex: 10,
			resp:          invoices[10:],
		},
	}

	for i, query := range addQueries {
		resp, err := db.InvoicesAddedSince(query.sinceAddIndex)
		if err != nil {
			t.Fatalf("unable to query: %v", err)
		}

		if !reflect.DeepEqual(query.resp, resp) {
			t.Fatalf("test #%v: expected %v, got %v", i,
				spew.Sdump(query.resp), spew.Sdump(resp))
		}
	}

	// We'll now only settle the latter half of each of those invoices.
	for i := 10; i < len(invoices); i++ {
		invoice := &invoices[i]

		paymentHash := sha256.Sum256(
			invoice.Terms.PaymentPreimage[:],
		)

		_, err := db.SettleInvoice(paymentHash, 0)
		if err != nil {
			t.Fatalf("unable to settle invoice: %v", err)
		}
	}

	invoices, err = db.FetchAllInvoices(false)
	if err != nil {
		t.Fatalf("unable to fetch invoices: %v", err)
	}

	// We'll slice off the first 10 invoices, as we only settled the last
	// 10.
	invoices = invoices[10:]

	// We'll now prepare an additional set of queries to ensure the settle
	// time series has properly been maintained in the database.
	settleQueries := []struct {
		sinceSettleIndex uint64

		resp []Invoice
	}{
		// If we specify a value of zero, we shouldn't get any settled
		// invoices back.
		{
			sinceSettleIndex: 0,
		},

		// If we specify a value well beyond the number of settled
		// invoices, we shouldn't get any invoices back.
		{
			sinceSettleIndex: 99999999,
		},

		// Using an index of 1 should result in the final 10 invoices
		// being returned, as we only settled those.
		{
			sinceSettleIndex: 1,
			resp:             invoices[1:],
		},
	}

	for i, query := range settleQueries {
		resp, err := db.InvoicesSettledSince(query.sinceSettleIndex)
		if err != nil {
			t.Fatalf("unable to query: %v", err)
		}

		if !reflect.DeepEqual(query.resp, resp) {
			t.Fatalf("test #%v: expected %v, got %v", i,
				spew.Sdump(query.resp), spew.Sdump(resp))
		}
	}
}