// Copyright (c) 2017 The btcsuite developers
// Copyright (c) 2017 The Lightning Network Developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.

package builder_test

import (
	"encoding/hex"
	"testing"

	"github.com/btcsuite/btcd/chaincfg/chainhash"
	"github.com/btcsuite/btcutil/gcs/builder"
)

var (
	// No need to allocate an err variable in every test
	err error

	// List of values for building a filter
	contents = [][]byte{
		[]byte("Alex"),
		[]byte("Bob"),
		[]byte("Charlie"),
		[]byte("Dick"),
		[]byte("Ed"),
		[]byte("Frank"),
		[]byte("George"),
		[]byte("Harry"),
		[]byte("Ilya"),
		[]byte("John"),
		[]byte("Kevin"),
		[]byte("Larry"),
		[]byte("Michael"),
		[]byte("Nate"),
		[]byte("Owen"),
		[]byte("Paul"),
		[]byte("Quentin"),
	}

	// List of values for querying a filter using MatchAny()
	contents2 = [][]byte{
		[]byte("Alice"),
		[]byte("Betty"),
		[]byte("Charmaine"),
		[]byte("Donna"),
		[]byte("Edith"),
		[]byte("Faina"),
		[]byte("Georgia"),
		[]byte("Hannah"),
		[]byte("Ilsbeth"),
		[]byte("Jennifer"),
		[]byte("Kayla"),
		[]byte("Lena"),
		[]byte("Michelle"),
		[]byte("Natalie"),
		[]byte("Ophelia"),
		[]byte("Peggy"),
		[]byte("Queenie"),
	}
)

// TestUseBlockHash tests using a block hash as a filter key.
func TestUseBlockHash(t *testing.T) {
	// Block hash #448710, pretty high difficulty.
	hash, err := chainhash.NewHashFromStr("000000000000000000496d7ff9bd2c96154a8d64260e8b3b411e625712abb14c")
	if err != nil {
		t.Fatalf("Hash from string failed: %s", err.Error())
	}

	// Create a Builder with a key hash and check that the key is derived
	// correctly.
	b := builder.WithKeyHash(hash)
	key, err := b.Key()
	if err != nil {
		t.Fatalf("Builder instantiation with key hash failed: %s",
			err.Error())
	}
	testKey := [16]byte{0x4c, 0xb1, 0xab, 0x12, 0x57, 0x62, 0x1e, 0x41,
		0x3b, 0x8b, 0x0e, 0x26, 0x64, 0x8d, 0x4a, 0x15}
	if key != testKey {
		t.Fatalf("Key not derived correctly from key hash:\n%s\n%s",
			hex.EncodeToString(key[:]),
			hex.EncodeToString(testKey[:]))
	}

	// Build a filter and test matches.
	b.AddEntries(contents)
	f, err := b.Build()
	match, err := f.Match(key, []byte("Nate"))
	if err != nil {
		t.Fatalf("Filter match failed: %s", err)
	}
	if !match {
		t.Fatal("Filter didn't match when it should have!")
	}
	match, err = f.Match(key, []byte("weks"))
	if err != nil {
		t.Fatalf("Filter match failed: %s", err)
	}
	if match {
		t.Logf("False positive match, should be 1 in 2**%d!",
			builder.DefaultP)
	}
}