// Copyright 2016 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 chequebook

import (
	"crypto/ecdsa"
	"math/big"
	"os"
	"path/filepath"
	"testing"
	"time"

	"github.com/ethereum/go-ethereum/accounts/abi/bind"
	"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/contracts/chequebook/contract"
	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/crypto"
)

var (
	key0, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
	key1, _ = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
	key2, _ = crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee")
	addr0   = crypto.PubkeyToAddress(key0.PublicKey)
	addr1   = crypto.PubkeyToAddress(key1.PublicKey)
	addr2   = crypto.PubkeyToAddress(key2.PublicKey)
)

func newTestBackend() *backends.SimulatedBackend {
	return backends.NewSimulatedBackend(core.GenesisAlloc{
		addr0: {Balance: big.NewInt(1000000000)},
		addr1: {Balance: big.NewInt(1000000000)},
		addr2: {Balance: big.NewInt(1000000000)},
	})
}

func deploy(prvKey *ecdsa.PrivateKey, amount *big.Int, backend *backends.SimulatedBackend) (common.Address, error) {
	deployTransactor := bind.NewKeyedTransactor(prvKey)
	deployTransactor.Value = amount
	addr, _, _, err := contract.DeployChequebook(deployTransactor, backend)
	if err != nil {
		return common.Address{}, err
	}
	backend.Commit()
	return addr, nil
}

func TestIssueAndReceive(t *testing.T) {
	path := filepath.Join(os.TempDir(), "chequebook-test.json")
	backend := newTestBackend()
	addr0, err := deploy(key0, big.NewInt(0), backend)
	if err != nil {
		t.Fatalf("deploy contract: expected no error, got %v", err)
	}
	chbook, err := NewChequebook(path, addr0, key0, backend)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	chbook.sent[addr1] = new(big.Int).SetUint64(42)
	amount := common.Big1

	if _, err = chbook.Issue(addr1, amount); err == nil {
		t.Fatalf("expected insufficient funds error, got none")
	}

	chbook.balance = new(big.Int).Set(common.Big1)
	if chbook.Balance().Cmp(common.Big1) != 0 {
		t.Fatalf("expected: %v, got %v", "0", chbook.Balance())
	}

	ch, err := chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	if chbook.Balance().Sign() != 0 {
		t.Errorf("expected: %v, got %v", "0", chbook.Balance())
	}

	chbox, err := NewInbox(key1, addr0, addr1, &key0.PublicKey, backend)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	received, err := chbox.Receive(ch)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	if received.Cmp(big.NewInt(43)) != 0 {
		t.Errorf("expected: %v, got %v", "43", received)
	}

}

func TestCheckbookFile(t *testing.T) {
	path := filepath.Join(os.TempDir(), "chequebook-test.json")
	backend := newTestBackend()
	chbook, err := NewChequebook(path, addr0, key0, backend)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	chbook.sent[addr1] = new(big.Int).SetUint64(42)
	chbook.balance = new(big.Int).Set(common.Big1)

	chbook.Save()

	chbook, err = LoadChequebook(path, key0, backend, false)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	if chbook.Balance().Cmp(common.Big1) != 0 {
		t.Errorf("expected: %v, got %v", "0", chbook.Balance())
	}

	var ch *Cheque
	if ch, err = chbook.Issue(addr1, common.Big1); err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	if ch.Amount.Cmp(new(big.Int).SetUint64(43)) != 0 {
		t.Errorf("expected: %v, got %v", "0", ch.Amount)
	}

	err = chbook.Save()
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
}

func TestVerifyErrors(t *testing.T) {
	path0 := filepath.Join(os.TempDir(), "chequebook-test-0.json")
	backend := newTestBackend()
	contr0, err := deploy(key0, common.Big2, backend)
	if err != nil {
		t.Errorf("expected no error, got %v", err)
	}
	chbook0, err := NewChequebook(path0, contr0, key0, backend)
	if err != nil {
		t.Errorf("expected no error, got %v", err)
	}

	path1 := filepath.Join(os.TempDir(), "chequebook-test-1.json")
	contr1, _ := deploy(key1, common.Big2, backend)
	chbook1, err := NewChequebook(path1, contr1, key1, backend)
	if err != nil {
		t.Errorf("expected no error, got %v", err)
	}

	chbook0.sent[addr1] = new(big.Int).SetUint64(42)
	chbook0.balance = new(big.Int).Set(common.Big2)
	chbook1.balance = new(big.Int).Set(common.Big1)
	amount := common.Big1
	ch0, err := chbook0.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	time.Sleep(5)
	chbox, err := NewInbox(key1, contr0, addr1, &key0.PublicKey, backend)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	received, err := chbox.Receive(ch0)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	if received.Cmp(big.NewInt(43)) != 0 {
		t.Errorf("expected: %v, got %v", "43", received)
	}

	ch1, err := chbook0.Issue(addr2, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	received, err = chbox.Receive(ch1)
	t.Logf("correct error: %v", err)
	if err == nil {
		t.Fatalf("expected receiver error, got none")
	}

	ch2, err := chbook1.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	received, err = chbox.Receive(ch2)
	t.Logf("correct error: %v", err)
	if err == nil {
		t.Fatalf("expected sender error, got none")
	}

	_, err = chbook1.Issue(addr1, new(big.Int).SetInt64(-1))
	t.Logf("correct error: %v", err)
	if err == nil {
		t.Fatalf("expected incorrect amount error, got none")
	}

	received, err = chbox.Receive(ch0)
	t.Logf("correct error: %v", err)
	if err == nil {
		t.Fatalf("expected incorrect amount error, got none")
	}

}

func TestDeposit(t *testing.T) {
	path0 := filepath.Join(os.TempDir(), "chequebook-test-0.json")
	backend := newTestBackend()
	contr0, _ := deploy(key0, new(big.Int), backend)

	chbook, err := NewChequebook(path0, contr0, key0, backend)
	if err != nil {
		t.Errorf("expected no error, got %v", err)
	}

	balance := new(big.Int).SetUint64(42)
	chbook.Deposit(balance)
	backend.Commit()
	if chbook.balance.Cmp(balance) != 0 {
		t.Fatalf("expected balance %v, got %v", balance, chbook.balance)
	}

	amount := common.Big1
	_, err = chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()
	exp := new(big.Int).SetUint64(41)
	if chbook.balance.Cmp(exp) != 0 {
		t.Fatalf("expected balance %v, got %v", exp, chbook.balance)
	}

	// autodeposit on each issue
	chbook.AutoDeposit(0, balance, balance)
	_, err = chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()
	_, err = chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()
	if chbook.balance.Cmp(balance) != 0 {
		t.Fatalf("expected balance %v, got %v", balance, chbook.balance)
	}

	// autodeposit off
	chbook.AutoDeposit(0, common.Big0, balance)
	_, err = chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()
	_, err = chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()

	exp = new(big.Int).SetUint64(40)
	if chbook.balance.Cmp(exp) != 0 {
		t.Fatalf("expected balance %v, got %v", exp, chbook.balance)
	}

	// autodeposit every 10ms if new cheque issued
	interval := 30 * time.Millisecond
	chbook.AutoDeposit(interval, common.Big1, balance)
	_, err = chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()
	_, err = chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()

	exp = new(big.Int).SetUint64(38)
	if chbook.balance.Cmp(exp) != 0 {
		t.Fatalf("expected balance %v, got %v", exp, chbook.balance)
	}

	time.Sleep(3 * interval)
	backend.Commit()
	if chbook.balance.Cmp(balance) != 0 {
		t.Fatalf("expected balance %v, got %v", balance, chbook.balance)
	}

	exp = new(big.Int).SetUint64(40)
	chbook.AutoDeposit(4*interval, exp, balance)
	_, err = chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()
	_, err = chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	time.Sleep(3 * interval)
	backend.Commit()
	if chbook.balance.Cmp(exp) != 0 {
		t.Fatalf("expected balance %v, got %v", exp, chbook.balance)
	}

	_, err = chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	time.Sleep(1 * interval)
	backend.Commit()

	if chbook.balance.Cmp(balance) != 0 {
		t.Fatalf("expected balance %v, got %v", balance, chbook.balance)
	}

	chbook.AutoDeposit(1*interval, common.Big0, balance)
	chbook.Stop()

	_, err = chbook.Issue(addr1, common.Big1)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()

	_, err = chbook.Issue(addr1, common.Big2)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	time.Sleep(1 * interval)
	backend.Commit()

	exp = new(big.Int).SetUint64(39)
	if chbook.balance.Cmp(exp) != 0 {
		t.Fatalf("expected balance %v, got %v", exp, chbook.balance)
	}

}

func TestCash(t *testing.T) {
	path := filepath.Join(os.TempDir(), "chequebook-test.json")
	backend := newTestBackend()
	contr0, _ := deploy(key0, common.Big2, backend)

	chbook, err := NewChequebook(path, contr0, key0, backend)
	if err != nil {
		t.Errorf("expected no error, got %v", err)
	}
	chbook.sent[addr1] = new(big.Int).SetUint64(42)
	amount := common.Big1
	chbook.balance = new(big.Int).Set(common.Big1)
	ch, err := chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()
	chbox, err := NewInbox(key1, contr0, addr1, &key0.PublicKey, backend)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	// cashing latest cheque
	if _, err = chbox.Receive(ch); err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	if _, err = ch.Cash(chbook.session); err != nil {
		t.Fatal("Cash failed:", err)
	}
	backend.Commit()

	chbook.balance = new(big.Int).Set(common.Big3)
	ch0, err := chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()
	ch1, err := chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()

	interval := 10 * time.Millisecond
	// setting autocash with interval of 10ms
	chbox.AutoCash(interval, nil)
	_, err = chbox.Receive(ch0)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	_, err = chbox.Receive(ch1)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()
	// after 3x interval time and 2 cheques received, exactly one cashing tx is sent
	time.Sleep(4 * interval)
	backend.Commit()

	// after stopping autocash no more tx are sent
	ch2, err := chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	chbox.Stop()
	_, err = chbox.Receive(ch2)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	time.Sleep(2 * interval)
	backend.Commit()

	// autocash below 1
	chbook.balance = big.NewInt(2)
	chbox.AutoCash(0, common.Big1)

	ch3, err := chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()

	ch4, err := chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()

	_, err = chbox.Receive(ch3)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()
	_, err = chbox.Receive(ch4)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()

	// autochash on receipt when maxUncashed is 0
	chbook.balance = new(big.Int).Set(common.Big2)
	chbox.AutoCash(0, common.Big0)

	ch5, err := chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()

	ch6, err := chbook.Issue(addr1, amount)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	_, err = chbox.Receive(ch5)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()

	_, err = chbox.Receive(ch6)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	backend.Commit()

}