// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package keystore

import (
	"fmt"
	"math/rand"
	"os"
	"path/filepath"
	"reflect"
	"testing"
	"time"

	"github.com/cespare/cp"
	"github.com/ethereum/go-ethereum/common"
	"github.com/harmony-one/harmony/accounts"
)

var (
	cachetestDir, _   = filepath.Abs(filepath.Join("testdata", "keystore"))
	cachetestAccounts = []accounts.Account{
		{
			Address: common.HexToAddress("7ef5a6135f1fd6a02593eedc869c6d41d934aef8"),
			URL:     accounts.URL{Scheme: KeyStoreScheme, Path: filepath.Join(cachetestDir, "UTC--2016-03-22T12-57-55.920751759Z--7ef5a6135f1fd6a02593eedc869c6d41d934aef8")},
		},
		{
			Address: common.HexToAddress("f466859ead1932d743d622cb74fc058882e8648a"),
			URL:     accounts.URL{Scheme: KeyStoreScheme, Path: filepath.Join(cachetestDir, "aaa")},
		},
		{
			Address: common.HexToAddress("289d485d9771714cce91d3393d764e1311907acc"),
			URL:     accounts.URL{Scheme: KeyStoreScheme, Path: filepath.Join(cachetestDir, "zzz")},
		},
	}
)

func waitForAccounts(wantAccounts []accounts.Account, ks *KeyStore) error {
	var list []accounts.Account
	for d := 200 * time.Millisecond; d < 8*time.Second; d *= 2 {
		list = ks.Accounts()
		if reflect.DeepEqual(list, wantAccounts) {
			// ks should have also received change notifications
			select {
			case <-ks.changes:
			default:
				return fmt.Errorf("wasn't notified of new accounts")
			}
			return nil
		}
		time.Sleep(d)
	}
	return fmt.Errorf("\ngot  %v\nwant %v", list, wantAccounts)
}

// TestUpdatedKeyfileContents tests that updating the contents of a keystore file
// is noticed by the watcher, and the account cache is updated accordingly
func TestUpdatedKeyfileContents(t *testing.T) {
	t.Parallel()

	// Create a temporary kesytore to test with
	rand.Seed(time.Now().UnixNano())
	dir := filepath.Join(os.TempDir(), fmt.Sprintf("eth-keystore-watch-test-%d-%d", os.Getpid(), rand.Int()))
	ks := NewKeyStore(dir, LightScryptN, LightScryptP)

	list := ks.Accounts()
	if len(list) > 0 {
		t.Error("initial account list not empty:", list)
	}
	time.Sleep(100 * time.Millisecond)

	// Create the directory and copy a key file into it.
	os.MkdirAll(dir, 0700)
	defer os.RemoveAll(dir)
	file := filepath.Join(dir, "aaa")

	// Place one of our testfiles in there
	if err := cp.CopyFile(file, cachetestAccounts[0].URL.Path); err != nil {
		t.Fatal(err)
	}

	// ks should see the account.
	wantAccounts := []accounts.Account{cachetestAccounts[0]}
	wantAccounts[0].URL = accounts.URL{Scheme: KeyStoreScheme, Path: file}
	if err := waitForAccounts(wantAccounts, ks); err != nil {
		t.Error(err)
		return
	}

	// needed so that modTime of `file` is different to its current value after forceCopyFile
	time.Sleep(1000 * time.Millisecond)

	// Now replace file contents
	if err := forceCopyFile(file, cachetestAccounts[1].URL.Path); err != nil {
		t.Fatal(err)
		return
	}
	wantAccounts = []accounts.Account{cachetestAccounts[1]}
	wantAccounts[0].URL = accounts.URL{Scheme: KeyStoreScheme, Path: file}
	if err := waitForAccounts(wantAccounts, ks); err != nil {
		t.Errorf("First replacement failed")
		t.Error(err)
		return
	}

	// needed so that modTime of `file` is different to its current value after forceCopyFile
	time.Sleep(1000 * time.Millisecond)

	// Now replace file contents again
	if err := forceCopyFile(file, cachetestAccounts[2].URL.Path); err != nil {
		t.Fatal(err)
		return
	}
	wantAccounts = []accounts.Account{cachetestAccounts[2]}
	wantAccounts[0].URL = accounts.URL{Scheme: KeyStoreScheme, Path: file}
	if err := waitForAccounts(wantAccounts, ks); err != nil {
		t.Errorf("Second replacement failed")
		t.Error(err)
		return
	}

	// needed so that modTime of `file` is different to its current value after io.WriteFile
	time.Sleep(1000 * time.Millisecond)

	// Now replace file contents with crap
	if err := os.WriteFile(file, []byte("foo"), 0644); err != nil {
		t.Fatal(err)
		return
	}
	if err := waitForAccounts([]accounts.Account{}, ks); err != nil {
		t.Errorf("Emptying account file failed")
		t.Error(err)
		return
	}
}

// forceCopyFile is like cp.CopyFile, but doesn't complain if the destination exists.
func forceCopyFile(dst, src string) error {
	data, err := os.ReadFile(src)
	if err != nil {
		return err
	}
	return os.WriteFile(dst, data, 0644)
}