// Copyright 2018 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

package main

import (
	"archive/tar"
	"bytes"
	"compress/gzip"
	"crypto/md5"
	"encoding/base64"
	"encoding/hex"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"path"
	"runtime"
	"strings"
	"testing"

	"github.com/ethereum/go-ethereum/cmd/swarm/testdata"
	"github.com/ethereum/go-ethereum/log"
	"github.com/ethereum/go-ethereum/swarm"
	"github.com/ethereum/go-ethereum/swarm/testutil"
)

const (
	DATABASE_FIXTURE_BZZ_ACCOUNT = "0aa159029fa13ffa8fa1c6fff6ebceface99d6a4"
	DATABASE_FIXTURE_PASSWORD    = "pass"
	FIXTURE_DATADIR_PREFIX       = "swarm/bzz-0aa159029fa13ffa8fa1c6fff6ebceface99d6a4"
	FixtureBaseKey               = "a9f22b3d77b4bdf5f3eefce995d6c8e7cecf2636f20956f08a0d1ed95adb52ad"
)

// TestCLISwarmExportImport perform the following test:
// 1. runs swarm node
// 2. uploads a random file
// 3. runs an export of the local datastore
// 4. runs a second swarm node
// 5. imports the exported datastore
// 6. fetches the uploaded random file from the second node
func TestCLISwarmExportImport(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip()
	}
	cluster := newTestCluster(t, 1)

	// generate random 1mb file
	content := testutil.RandomBytes(1, 1000000)
	fileName := testutil.TempFileWithContent(t, string(content))
	defer os.Remove(fileName)

	// upload the file with 'swarm up' and expect a hash
	up := runSwarm(t, "--bzzapi", cluster.Nodes[0].URL, "up", fileName)
	_, matches := up.ExpectRegexp(`[a-f\d]{64}`)
	up.ExpectExit()
	hash := matches[0]

	var info swarm.Info
	if err := cluster.Nodes[0].Client.Call(&info, "bzz_info"); err != nil {
		t.Fatal(err)
	}

	cluster.Stop()
	defer cluster.Cleanup()

	// generate an export.tar
	exportCmd := runSwarm(t, "db", "export", info.Path+"/chunks", info.Path+"/export.tar", strings.TrimPrefix(info.BzzKey, "0x"))
	exportCmd.ExpectExit()

	// start second cluster
	cluster2 := newTestCluster(t, 1)

	var info2 swarm.Info
	if err := cluster2.Nodes[0].Client.Call(&info2, "bzz_info"); err != nil {
		t.Fatal(err)
	}

	// stop second cluster, so that we close LevelDB
	cluster2.Stop()
	defer cluster2.Cleanup()

	// import the export.tar
	importCmd := runSwarm(t, "db", "import", info2.Path+"/chunks", info.Path+"/export.tar", strings.TrimPrefix(info2.BzzKey, "0x"))
	importCmd.ExpectExit()

	// spin second cluster back up
	cluster2.StartExistingNodes(t, 1, strings.TrimPrefix(info2.BzzAccount, "0x"))

	// try to fetch imported file
	res, err := http.Get(cluster2.Nodes[0].URL + "/bzz:/" + hash)
	if err != nil {
		t.Fatal(err)
	}

	if res.StatusCode != 200 {
		t.Fatalf("expected HTTP status %d, got %s", 200, res.Status)
	}

	// compare downloaded file with the generated random file
	mustEqualFiles(t, bytes.NewReader(content), res.Body)
}

// TestExportLegacyToNew checks that an old database gets imported correctly into the new localstore structure
// The test sequence is as follows:
// 1. unpack database fixture to tmp dir
// 2. try to open with new swarm binary that should complain about old database
// 3. export from old database
// 4. remove the chunks folder
// 5. import the dump
// 6. file should be accessible
func TestExportLegacyToNew(t *testing.T) {
	/*
		fixture	bzz account 0aa159029fa13ffa8fa1c6fff6ebceface99d6a4
	*/
	const UPLOADED_FILE_MD5_HASH = "a001fdae53ba50cae584b8b02b06f821"
	const UPLOADED_HASH = "67a86082ee0ea1bc7dd8d955bb1e14d04f61d55ae6a4b37b3d0296a3a95e454a"
	tmpdir, err := ioutil.TempDir("", "swarm-test")
	log.Trace("running legacy datastore migration test", "temp dir", tmpdir)
	defer os.RemoveAll(tmpdir)
	if err != nil {
		t.Fatal(err)
	}
	inflateBase64Gzip(t, testdata.DATADIR_MIGRATION_FIXTURE, tmpdir)

	tmpPassword := testutil.TempFileWithContent(t, DATABASE_FIXTURE_PASSWORD)
	defer os.Remove(tmpPassword)

	flags := []string{
		"--datadir", tmpdir,
		"--bzzaccount", DATABASE_FIXTURE_BZZ_ACCOUNT,
		"--password", tmpPassword,
	}

	newSwarmOldDb := runSwarm(t, flags...)
	_, matches := newSwarmOldDb.ExpectRegexp(".+")
	newSwarmOldDb.ExpectExit()

	if len(matches) == 0 {
		t.Fatalf("stdout not matched")
	}

	if newSwarmOldDb.ExitStatus() == 0 {
		t.Fatal("should error")
	}
	t.Log("exporting legacy database")
	actualDataDir := path.Join(tmpdir, FIXTURE_DATADIR_PREFIX)
	exportCmd := runSwarm(t, "--verbosity", "5", "db", "export", actualDataDir+"/chunks", tmpdir+"/export.tar", FixtureBaseKey)
	exportCmd.ExpectExit()

	stat, err := os.Stat(tmpdir + "/export.tar")
	if err != nil {
		t.Fatal(err)
	}

	// make some silly size assumption
	if stat.Size() < 90000 {
		t.Fatal("export size too small")
	}
	t.Log("removing chunk datadir")
	err = os.RemoveAll(path.Join(actualDataDir, "chunks"))
	if err != nil {
		t.Fatal(err)
	}

	// start second cluster
	cluster2 := newTestCluster(t, 1)
	var info2 swarm.Info
	if err := cluster2.Nodes[0].Client.Call(&info2, "bzz_info"); err != nil {
		t.Fatal(err)
	}

	// stop second cluster, so that we close LevelDB
	cluster2.Stop()
	defer cluster2.Cleanup()

	// import the export.tar
	importCmd := runSwarm(t, "db", "import", "--legacy", info2.Path+"/chunks", tmpdir+"/export.tar", strings.TrimPrefix(info2.BzzKey, "0x"))
	importCmd.ExpectExit()

	// spin second cluster back up
	cluster2.StartExistingNodes(t, 1, strings.TrimPrefix(info2.BzzAccount, "0x"))
	t.Log("trying to http get the file")
	// try to fetch imported file
	res, err := http.Get(cluster2.Nodes[0].URL + "/bzz:/" + UPLOADED_HASH)
	if err != nil {
		t.Fatal(err)
	}

	if res.StatusCode != 200 {
		t.Fatalf("expected HTTP status %d, got %s", 200, res.Status)
	}
	h := md5.New()
	if _, err := io.Copy(h, res.Body); err != nil {
		t.Fatal(err)
	}

	sum := h.Sum(nil)

	b, err := hex.DecodeString(UPLOADED_FILE_MD5_HASH)
	if err != nil {
		t.Fatal(err)
	}

	if !bytes.Equal(sum, b) {
		t.Fatal("should be equal")
	}
}

func mustEqualFiles(t *testing.T, up io.Reader, down io.Reader) {
	h := md5.New()
	upLen, err := io.Copy(h, up)
	if err != nil {
		t.Fatal(err)
	}
	upHash := h.Sum(nil)
	h.Reset()
	downLen, err := io.Copy(h, down)
	if err != nil {
		t.Fatal(err)
	}
	downHash := h.Sum(nil)

	if !bytes.Equal(upHash, downHash) || upLen != downLen {
		t.Fatalf("downloaded imported file md5=%x (length %v) is not the same as the generated one mp5=%x (length %v)", downHash, downLen, upHash, upLen)
	}
}

func inflateBase64Gzip(t *testing.T, base64File, directory string) {
	t.Helper()

	f := base64.NewDecoder(base64.StdEncoding, strings.NewReader(base64File))
	gzf, err := gzip.NewReader(f)
	if err != nil {
		t.Fatal(err)
	}

	tarReader := tar.NewReader(gzf)

	for {
		header, err := tarReader.Next()
		if err == io.EOF {
			break
		}

		if err != nil {
			t.Fatal(err)
		}

		name := header.Name

		switch header.Typeflag {
		case tar.TypeDir:
			err := os.Mkdir(path.Join(directory, name), os.ModePerm)
			if err != nil {
				t.Fatal(err)
			}
		case tar.TypeReg:
			file, err := os.Create(path.Join(directory, name))
			if err != nil {
				t.Fatal(err)
			}
			if _, err := io.Copy(file, tarReader); err != nil {
				t.Fatal(err)
			}
		default:
			t.Fatal("shouldn't happen")
		}
	}
}