// 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/>.

// This file contains some shares testing functionality, common to  multiple
// different files and modules being tested.

package les

import (
	"crypto/ecdsa"
	"crypto/rand"
	"math/big"
	"sync"
	"testing"
	"time"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/consensus/ethash"
	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/core/vm"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/ethdb"
	"github.com/ethereum/go-ethereum/event"
	"github.com/ethereum/go-ethereum/les/flowcontrol"
	"github.com/ethereum/go-ethereum/light"
	"github.com/ethereum/go-ethereum/p2p"
	"github.com/ethereum/go-ethereum/p2p/discover"
	"github.com/ethereum/go-ethereum/params"
)

var (
	testBankKey, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
	testBankAddress = crypto.PubkeyToAddress(testBankKey.PublicKey)
	testBankFunds   = big.NewInt(1000000)

	acc1Key, _ = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
	acc2Key, _ = crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee")
	acc1Addr   = crypto.PubkeyToAddress(acc1Key.PublicKey)
	acc2Addr   = crypto.PubkeyToAddress(acc2Key.PublicKey)

	testContractCode         = common.Hex2Bytes("606060405260cc8060106000396000f360606040526000357c01000000000000000000000000000000000000000000000000000000009004806360cd2685146041578063c16431b914606b57603f565b005b6055600480803590602001909190505060a9565b6040518082815260200191505060405180910390f35b60886004808035906020019091908035906020019091905050608a565b005b80600060005083606481101560025790900160005b50819055505b5050565b6000600060005082606481101560025790900160005b5054905060c7565b91905056")
	testContractAddr         common.Address
	testContractCodeDeployed = testContractCode[16:]
	testContractDeployed     = uint64(2)

	testBufLimit = uint64(100)

	bigTxGas = new(big.Int).SetUint64(params.TxGas)
)

/*
contract test {

    uint256[100] data;

    function Put(uint256 addr, uint256 value) {
        data[addr] = value;
    }

    function Get(uint256 addr) constant returns (uint256 value) {
        return data[addr];
    }
}
*/

func testChainGen(i int, block *core.BlockGen) {
	signer := types.HomesteadSigner{}

	switch i {
	case 0:
		// In block 1, the test bank sends account #1 some ether.
		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(10000), bigTxGas, nil, nil), signer, testBankKey)
		block.AddTx(tx)
	case 1:
		// In block 2, the test bank sends some more ether to account #1.
		// acc1Addr passes it on to account #2.
		// acc1Addr creates a test contract.
		tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, testBankKey)
		nonce := block.TxNonce(acc1Addr)
		tx2, _ := types.SignTx(types.NewTransaction(nonce, acc2Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, acc1Key)
		nonce++
		tx3, _ := types.SignTx(types.NewContractCreation(nonce, big.NewInt(0), big.NewInt(200000), big.NewInt(0), testContractCode), signer, acc1Key)
		testContractAddr = crypto.CreateAddress(acc1Addr, nonce)
		block.AddTx(tx1)
		block.AddTx(tx2)
		block.AddTx(tx3)
	case 2:
		// Block 3 is empty but was mined by account #2.
		block.SetCoinbase(acc2Addr)
		block.SetExtra([]byte("yeehaw"))
		data := common.Hex2Bytes("C16431B900000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000001")
		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), testContractAddr, big.NewInt(0), big.NewInt(100000), nil, data), signer, testBankKey)
		block.AddTx(tx)
	case 3:
		// Block 4 includes blocks 2 and 3 as uncle headers (with modified extra data).
		b2 := block.PrevBlock(1).Header()
		b2.Extra = []byte("foo")
		block.AddUncle(b2)
		b3 := block.PrevBlock(2).Header()
		b3.Extra = []byte("foo")
		block.AddUncle(b3)
		data := common.Hex2Bytes("C16431B900000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000002")
		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), testContractAddr, big.NewInt(0), big.NewInt(100000), nil, data), signer, testBankKey)
		block.AddTx(tx)
	}
}

func testRCL() RequestCostList {
	cl := make(RequestCostList, len(reqList))
	for i, code := range reqList {
		cl[i].MsgCode = code
		cl[i].BaseCost = 0
		cl[i].ReqCost = 0
	}
	return cl
}

// newTestProtocolManager creates a new protocol manager for testing purposes,
// with the given number of blocks already known, and potential notification
// channels for different events.
func newTestProtocolManager(lightSync bool, blocks int, generator func(int, *core.BlockGen)) (*ProtocolManager, ethdb.Database, *LesOdr, error) {
	var (
		evmux  = new(event.TypeMux)
		engine = ethash.NewFaker()
		db, _  = ethdb.NewMemDatabase()
		gspec  = core.Genesis{
			Config: params.TestChainConfig,
			Alloc:  core.GenesisAlloc{testBankAddress: {Balance: testBankFunds}},
		}
		genesis = gspec.MustCommit(db)
		odr     *LesOdr
		chain   BlockChain
	)

	if lightSync {
		odr = NewLesOdr(db)
		chain, _ = light.NewLightChain(odr, gspec.Config, engine, evmux)
	} else {
		blockchain, _ := core.NewBlockChain(db, gspec.Config, engine, evmux, vm.Config{})
		gchain, _ := core.GenerateChain(gspec.Config, genesis, db, blocks, generator)
		if _, err := blockchain.InsertChain(gchain); err != nil {
			panic(err)
		}
		chain = blockchain
	}

	pm, err := NewProtocolManager(gspec.Config, lightSync, NetworkId, evmux, engine, chain, nil, db, odr, nil)
	if err != nil {
		return nil, nil, nil, err
	}
	if !lightSync {
		srv := &LesServer{protocolManager: pm}
		pm.server = srv

		srv.defParams = &flowcontrol.ServerParams{
			BufLimit:    testBufLimit,
			MinRecharge: 1,
		}

		srv.fcManager = flowcontrol.NewClientManager(50, 10, 1000000000)
		srv.fcCostStats = newCostStats(nil)
	}
	pm.Start(nil)
	return pm, db, odr, nil
}

// newTestProtocolManagerMust creates a new protocol manager for testing purposes,
// with the given number of blocks already known, and potential notification
// channels for different events. In case of an error, the constructor force-
// fails the test.
func newTestProtocolManagerMust(t *testing.T, lightSync bool, blocks int, generator func(int, *core.BlockGen)) (*ProtocolManager, ethdb.Database, *LesOdr) {
	pm, db, odr, err := newTestProtocolManager(lightSync, blocks, generator)
	if err != nil {
		t.Fatalf("Failed to create protocol manager: %v", err)
	}
	return pm, db, odr
}

// testTxPool is a fake, helper transaction pool for testing purposes
type testTxPool struct {
	pool  []*types.Transaction        // Collection of all transactions
	added chan<- []*types.Transaction // Notification channel for new transactions

	lock sync.RWMutex // Protects the transaction pool
}

// AddTransactions appends a batch of transactions to the pool, and notifies any
// listeners if the addition channel is non nil
func (p *testTxPool) AddBatch(txs []*types.Transaction) {
	p.lock.Lock()
	defer p.lock.Unlock()

	p.pool = append(p.pool, txs...)
	if p.added != nil {
		p.added <- txs
	}
}

// GetTransactions returns all the transactions known to the pool
func (p *testTxPool) GetTransactions() types.Transactions {
	p.lock.RLock()
	defer p.lock.RUnlock()

	txs := make([]*types.Transaction, len(p.pool))
	copy(txs, p.pool)

	return txs
}

// newTestTransaction create a new dummy transaction.
func newTestTransaction(from *ecdsa.PrivateKey, nonce uint64, datasize int) *types.Transaction {
	tx := types.NewTransaction(nonce, common.Address{}, big.NewInt(0), big.NewInt(100000), big.NewInt(0), make([]byte, datasize))
	tx, _ = types.SignTx(tx, types.HomesteadSigner{}, from)

	return tx
}

// testPeer is a simulated peer to allow testing direct network calls.
type testPeer struct {
	net p2p.MsgReadWriter // Network layer reader/writer to simulate remote messaging
	app *p2p.MsgPipeRW    // Application layer reader/writer to simulate the local side
	*peer
}

// newTestPeer creates a new peer registered at the given protocol manager.
func newTestPeer(t *testing.T, name string, version int, pm *ProtocolManager, shake bool) (*testPeer, <-chan error) {
	// Create a message pipe to communicate through
	app, net := p2p.MsgPipe()

	// Generate a random id and create the peer
	var id discover.NodeID
	rand.Read(id[:])

	peer := pm.newPeer(version, NetworkId, p2p.NewPeer(id, name, nil), net)

	// Start the peer on a new thread
	errc := make(chan error, 1)
	go func() {
		select {
		case pm.newPeerCh <- peer:
			errc <- pm.handle(peer)
		case <-pm.quitSync:
			errc <- p2p.DiscQuitting
		}
	}()
	tp := &testPeer{
		app:  app,
		net:  net,
		peer: peer,
	}
	// Execute any implicitly requested handshakes and return
	if shake {
		td, head, genesis := pm.blockchain.Status()
		headNum := pm.blockchain.CurrentHeader().Number.Uint64()
		tp.handshake(t, td, head, headNum, genesis)
	}
	return tp, errc
}

func newTestPeerPair(name string, version int, pm, pm2 *ProtocolManager) (*peer, <-chan error, *peer, <-chan error) {
	// Create a message pipe to communicate through
	app, net := p2p.MsgPipe()

	// Generate a random id and create the peer
	var id discover.NodeID
	rand.Read(id[:])

	peer := pm.newPeer(version, NetworkId, p2p.NewPeer(id, name, nil), net)
	peer2 := pm2.newPeer(version, NetworkId, p2p.NewPeer(id, name, nil), app)

	// Start the peer on a new thread
	errc := make(chan error, 1)
	errc2 := make(chan error, 1)
	go func() {
		select {
		case pm.newPeerCh <- peer:
			errc <- pm.handle(peer)
		case <-pm.quitSync:
			errc <- p2p.DiscQuitting
		}
	}()
	go func() {
		select {
		case pm2.newPeerCh <- peer2:
			errc2 <- pm2.handle(peer2)
		case <-pm2.quitSync:
			errc2 <- p2p.DiscQuitting
		}
	}()
	return peer, errc, peer2, errc2
}

// handshake simulates a trivial handshake that expects the same state from the
// remote side as we are simulating locally.
func (p *testPeer) handshake(t *testing.T, td *big.Int, head common.Hash, headNum uint64, genesis common.Hash) {
	var expList keyValueList
	expList = expList.add("protocolVersion", uint64(p.version))
	expList = expList.add("networkId", uint64(NetworkId))
	expList = expList.add("headTd", td)
	expList = expList.add("headHash", head)
	expList = expList.add("headNum", headNum)
	expList = expList.add("genesisHash", genesis)
	sendList := make(keyValueList, len(expList))
	copy(sendList, expList)
	expList = expList.add("serveHeaders", nil)
	expList = expList.add("serveChainSince", uint64(0))
	expList = expList.add("serveStateSince", uint64(0))
	expList = expList.add("txRelay", nil)
	expList = expList.add("flowControl/BL", testBufLimit)
	expList = expList.add("flowControl/MRR", uint64(1))
	expList = expList.add("flowControl/MRC", testRCL())

	if err := p2p.ExpectMsg(p.app, StatusMsg, expList); err != nil {
		t.Fatalf("status recv: %v", err)
	}
	if err := p2p.Send(p.app, StatusMsg, sendList); err != nil {
		t.Fatalf("status send: %v", err)
	}

	p.fcServerParams = &flowcontrol.ServerParams{
		BufLimit:    testBufLimit,
		MinRecharge: 1,
	}
}

// close terminates the local side of the peer, notifying the remote protocol
// manager of termination.
func (p *testPeer) close() {
	p.app.Close()
}

type testServerPool struct {
	peer *peer
	lock sync.RWMutex
}

func (p *testServerPool) setPeer(peer *peer) {
	p.lock.Lock()
	defer p.lock.Unlock()

	p.peer = peer
}

func (p *testServerPool) getAllPeers() map[distPeer]struct{} {
	p.lock.RLock()
	defer p.lock.RUnlock()

	m := make(map[distPeer]struct{})
	if p.peer != nil {
		m[p.peer] = struct{}{}
	}
	return m
}

func (p *testServerPool) adjustResponseTime(*poolEntry, time.Duration, bool) {

}