// Copyright (c) 2015-2016 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.

package txsort_test

import (
	"bytes"
	"encoding/hex"
	"io/ioutil"
	"path/filepath"
	"testing"

	"github.com/daglabs/btcd/util/txsort"
	"github.com/daglabs/btcd/wire"
)

// TestSort ensures the transaction sorting works according to the BIP.
func TestSort(t *testing.T) {
	tests := []struct {
		name         string
		hexFile      string
		isSorted     bool
		unsortedHash string
		sortedHash   string
	}{
		{
			name:         "first test case from BIP 69 - sorts inputs only, based on hash",
			hexFile:      "bip69-1.hex",
			isSorted:     false,
			unsortedHash: "942436554228bcff3af7825cc733f58df686166943da87347f1dfd77ace0f8cf",
			sortedHash:   "a730bfdb5efc611dbf6b1cf10b16477f60be647ac95009d9b655f59f09fbe7cb",
		},
		{
			name:         "second test case from BIP 69 - already sorted",
			hexFile:      "bip69-2.hex",
			isSorted:     true,
			unsortedHash: "81812ee14ff0e57582eb1520630812838d8fbf2a278517b7ff89e82463f6a558",
			sortedHash:   "81812ee14ff0e57582eb1520630812838d8fbf2a278517b7ff89e82463f6a558",
		},
		{
			name:         "block 100001 tx[1] - sorts outputs only, based on amount",
			hexFile:      "bip69-3.hex",
			isSorted:     false,
			unsortedHash: "73d990869a7e3095ba06cc2c6718b4f210f72f6099643d2c6fe4dd93d32a49cf",
			sortedHash:   "5c2b807e2fff4dadea373e2f2a41a6d4808675bc478a3448f76bbbeec6fae310",
		},
		{
			name:         "block 100001 tx[2] - sorts both inputs and outputs",
			hexFile:      "bip69-4.hex",
			isSorted:     false,
			unsortedHash: "cefbcc2b6513392c9296a866e8ca9e3fc832355b454c6897aedbf2159f958fd3",
			sortedHash:   "4e3573d75a3aa02aeb3508f8203c52f0154d19ecb0cb0ef2e00ec3fa803baa5d",
		},
		{
			name:         "block 100998 tx[6] - sorts outputs only, based on output script",
			hexFile:      "bip69-5.hex",
			isSorted:     false,
			unsortedHash: "f79ed295b9d8a3c9813cc2b207d267753755503258bc9ac887f2d5495e8b6140",
			sortedHash:   "a90123db6e884f821d3228da70e7a810d4797d43379d40b71c8e214c7104c59a",
		},
	}

	for _, test := range tests {
		// Load and deserialize the test transaction.
		filePath := filepath.Join("testdata", test.hexFile)
		txHexBytes, err := ioutil.ReadFile(filePath)
		if err != nil {
			t.Errorf("ReadFile (%s): failed to read test file: %v",
				test.name, err)
			continue
		}
		txBytes, err := hex.DecodeString(string(txHexBytes))
		if err != nil {
			t.Errorf("DecodeString (%s): failed to decode tx: %v",
				test.name, err)
			continue
		}
		var tx wire.MsgTx
		err = tx.Deserialize(bytes.NewReader(txBytes))
		if err != nil {
			t.Errorf("Deserialize (%s): unexpected error %v",
				test.name, err)
			continue
		}

		// Ensure the sort order of the original transaction matches the
		// expected value.
		if got := txsort.IsSorted(&tx); got != test.isSorted {
			t.Errorf("IsSorted (%s): sort does not match "+
				"expected - got %v, want %v", test.name, got,
				test.isSorted)
			continue
		}

		// Sort the transaction and ensure the resulting hash is the
		// expected value.
		sortedTx := txsort.Sort(&tx)
		if got := sortedTx.TxHash().String(); got != test.sortedHash {
			t.Errorf("Sort (%s): sorted hash does not match "+
				"expected - got %v, want %v", test.name, got,
				test.sortedHash)
			continue
		}

		// Ensure the original transaction is not modified.
		if got := tx.TxHash().String(); got != test.unsortedHash {
			t.Errorf("Sort (%s): unsorted hash does not match "+
				"expected - got %v, want %v", test.name, got,
				test.unsortedHash)
			continue
		}

		// Now sort the transaction using the mutable version and ensure
		// the resulting hash is the expected value.
		txsort.InPlaceSort(&tx)
		if got := tx.TxHash().String(); got != test.sortedHash {
			t.Errorf("SortMutate (%s): sorted hash does not match "+
				"expected - got %v, want %v", test.name, got,
				test.sortedHash)
			continue
		}
	}
}