package disputegame

import (
	"context"
	"encoding/binary"
	"fmt"
	"math"
	"math/big"
	"testing"
	"time"

	"github.com/ethereum-optimism/optimism/cannon/mipsevm"
	"github.com/ethereum-optimism/optimism/op-bindings/bindings"
	"github.com/ethereum-optimism/optimism/op-chain-ops/deployer"
	"github.com/ethereum-optimism/optimism/op-chain-ops/genesis"
	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/trace/alphabet"
	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/trace/cannon"
	"github.com/ethereum-optimism/optimism/op-challenger/metrics"
	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils/challenger"
	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils/l2oo"
	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils/transactions"
	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils/wait"
	"github.com/ethereum-optimism/optimism/op-node/rollup"
	"github.com/ethereum-optimism/optimism/op-node/testlog"
	"github.com/ethereum/go-ethereum/accounts/abi/bind"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/ethclient"
	"github.com/ethereum/go-ethereum/log"
	"github.com/stretchr/testify/require"
)

const alphabetGameType uint8 = 255
const cannonGameType uint8 = 0
const alphabetGameDepth = 4
const lastAlphabetTraceIndex = 1<<alphabetGameDepth - 1

type Status uint8

const (
	StatusInProgress Status = iota
	StatusChallengerWins
	StatusDefenderWins
)

func (s Status) String() string {
	switch s {
	case StatusInProgress:
		return "In Progress"
	case StatusChallengerWins:
		return "Challenger Wins"
	case StatusDefenderWins:
		return "Defender Wins"
	default:
		return fmt.Sprintf("Unknown status: %v", int(s))
	}
}

var CorrectAlphabet = "abcdefghijklmnop"

type FactoryHelper struct {
	t           *testing.T
	require     *require.Assertions
	client      *ethclient.Client
	opts        *bind.TransactOpts
	factoryAddr common.Address
	factory     *bindings.DisputeGameFactory
	blockOracle *bindings.BlockOracle
	l2ooHelper  *l2oo.L2OOHelper
}

func NewFactoryHelper(t *testing.T, ctx context.Context, deployments *genesis.L1Deployments, client *ethclient.Client) *FactoryHelper {
	require := require.New(t)
	chainID, err := client.ChainID(ctx)
	require.NoError(err)
	opts, err := bind.NewKeyedTransactorWithChainID(deployer.TestKey, chainID)
	require.NoError(err)

	require.NotNil(deployments, "No deployments")
	factoryAddr := deployments.DisputeGameFactoryProxy
	factory, err := bindings.NewDisputeGameFactory(factoryAddr, client)
	require.NoError(err)
	blockOracle, err := bindings.NewBlockOracle(deployments.BlockOracle, client)
	require.NoError(err)

	return &FactoryHelper{
		t:           t,
		require:     require,
		client:      client,
		opts:        opts,
		factory:     factory,
		factoryAddr: factoryAddr,
		blockOracle: blockOracle,
		l2ooHelper:  l2oo.NewL2OOHelperReadOnly(t, deployments, client),
	}
}

func (h *FactoryHelper) StartAlphabetGame(ctx context.Context, claimedAlphabet string) *AlphabetGameHelper {
	l2BlockNumber := h.waitForProposals(ctx)
	l1Head := h.checkpointL1Block(ctx)

	ctx, cancel := context.WithTimeout(ctx, 1*time.Minute)
	defer cancel()

	trace := alphabet.NewTraceProvider(claimedAlphabet, alphabetGameDepth)
	rootClaim, err := trace.Get(ctx, lastAlphabetTraceIndex)
	h.require.NoError(err, "get root claim")
	extraData := make([]byte, 64)
	binary.BigEndian.PutUint64(extraData[24:], l2BlockNumber)
	binary.BigEndian.PutUint64(extraData[56:], l1Head.Uint64())
	tx, err := transactions.PadGasEstimate(h.opts, 2, func(opts *bind.TransactOpts) (*types.Transaction, error) {
		return h.factory.Create(opts, alphabetGameType, rootClaim, extraData)
	})
	h.require.NoError(err, "create fault dispute game")
	h.opts.GasLimit = 0
	rcpt, err := wait.ForReceiptOK(ctx, h.client, tx.Hash())
	h.require.NoError(err, "wait for create fault dispute game receipt to be OK")
	h.require.Len(rcpt.Logs, 1, "should have emitted a single DisputeGameCreated event")
	createdEvent, err := h.factory.ParseDisputeGameCreated(*rcpt.Logs[0])
	h.require.NoError(err)
	game, err := bindings.NewFaultDisputeGame(createdEvent.DisputeProxy, h.client)
	h.require.NoError(err)

	return &AlphabetGameHelper{
		FaultGameHelper: FaultGameHelper{
			t:           h.t,
			require:     h.require,
			client:      h.client,
			opts:        h.opts,
			game:        game,
			factoryAddr: h.factoryAddr,
			addr:        createdEvent.DisputeProxy,
		},
		claimedAlphabet: claimedAlphabet,
	}
}

func (h *FactoryHelper) StartCannonGame(ctx context.Context, rootClaim common.Hash) *CannonGameHelper {
	l2BlockNumber, l1Head := h.prepareCannonGame(ctx)
	return h.createCannonGame(ctx, l2BlockNumber, l1Head, rootClaim)
}

func (h *FactoryHelper) StartCannonGameWithCorrectRoot(ctx context.Context, rollupCfg *rollup.Config, l2Genesis *core.Genesis, l1Endpoint string, l2Endpoint string, options ...challenger.Option) (*CannonGameHelper, *HonestHelper) {
	l2BlockNumber, l1Head := h.prepareCannonGame(ctx)
	challengerOpts := []challenger.Option{
		challenger.WithCannon(h.t, rollupCfg, l2Genesis, l2Endpoint),
		challenger.WithFactoryAddress(h.factoryAddr),
	}
	challengerOpts = append(challengerOpts, options...)
	cfg := challenger.NewChallengerConfig(h.t, l1Endpoint, challengerOpts...)
	opts := &bind.CallOpts{Context: ctx}
	challengedOutput := h.l2ooHelper.GetL2OutputAfter(ctx, l2BlockNumber)
	agreedOutput := h.l2ooHelper.GetL2OutputBefore(ctx, l2BlockNumber)
	l1BlockInfo, err := h.blockOracle.Load(opts, l1Head)
	h.require.NoError(err, "Fetch L1 block info")

	l2Client, err := ethclient.DialContext(ctx, cfg.CannonL2)
	if err != nil {
		h.require.NoErrorf(err, "Failed to dial l2 client %v", l2Endpoint)
	}
	defer l2Client.Close()
	agreedHeader, err := l2Client.HeaderByNumber(ctx, agreedOutput.L2BlockNumber)
	if err != nil {
		h.require.NoErrorf(err, "Failed to fetch L2 block header %v", agreedOutput.L2BlockNumber)
	}

	inputs := cannon.LocalGameInputs{
		L1Head:        l1BlockInfo.Hash,
		L2Head:        agreedHeader.Hash(),
		L2OutputRoot:  agreedOutput.OutputRoot,
		L2Claim:       challengedOutput.OutputRoot,
		L2BlockNumber: challengedOutput.L2BlockNumber,
	}
	provider := cannon.NewTraceProviderFromInputs(testlog.Logger(h.t, log.LvlInfo).New("role", "CorrectTrace"), metrics.NoopMetrics, cfg, inputs, cfg.Datadir)
	rootClaim, err := provider.Get(ctx, math.MaxUint64)
	h.require.NoError(err, "Compute correct root hash")
	// Override the VM status to claim the root is invalid
	// Otherwise creating the game will fail
	rootClaim[0] = mipsevm.VMStatusInvalid

	game := h.createCannonGame(ctx, l2BlockNumber, l1Head, rootClaim)
	honestHelper := &HonestHelper{
		t:            h.t,
		require:      h.require,
		game:         &game.FaultGameHelper,
		correctTrace: provider,
	}
	return game, honestHelper
}

func (h *FactoryHelper) createCannonGame(ctx context.Context, l2BlockNumber uint64, l1Head *big.Int, rootClaim common.Hash) *CannonGameHelper {
	ctx, cancel := context.WithTimeout(ctx, 1*time.Minute)
	defer cancel()

	extraData := make([]byte, 64)
	binary.BigEndian.PutUint64(extraData[24:], l2BlockNumber)
	binary.BigEndian.PutUint64(extraData[56:], l1Head.Uint64())
	tx, err := transactions.PadGasEstimate(h.opts, 2, func(opts *bind.TransactOpts) (*types.Transaction, error) {
		return h.factory.Create(opts, cannonGameType, rootClaim, extraData)
	})
	h.require.NoError(err, "create fault dispute game")
	rcpt, err := wait.ForReceiptOK(ctx, h.client, tx.Hash())
	h.require.NoError(err, "wait for create fault dispute game receipt to be OK")
	h.require.Len(rcpt.Logs, 1, "should have emitted a single DisputeGameCreated event")
	createdEvent, err := h.factory.ParseDisputeGameCreated(*rcpt.Logs[0])
	h.require.NoError(err)
	game, err := bindings.NewFaultDisputeGame(createdEvent.DisputeProxy, h.client)
	h.require.NoError(err)

	return &CannonGameHelper{
		FaultGameHelper: FaultGameHelper{
			t:           h.t,
			require:     h.require,
			client:      h.client,
			opts:        h.opts,
			game:        game,
			factoryAddr: h.factoryAddr,
			addr:        createdEvent.DisputeProxy,
		},
	}
}

func (h *FactoryHelper) StartChallenger(ctx context.Context, l1Endpoint string, name string, options ...challenger.Option) *challenger.Helper {
	opts := []challenger.Option{
		challenger.WithFactoryAddress(h.factoryAddr),
	}
	opts = append(opts, options...)
	c := challenger.NewChallenger(h.t, ctx, l1Endpoint, name, opts...)
	h.t.Cleanup(func() {
		_ = c.Close()
	})
	return c
}

func (h *FactoryHelper) prepareCannonGame(ctx context.Context) (uint64, *big.Int) {
	l2BlockNumber := h.waitForProposals(ctx)
	l1Head := h.checkpointL1Block(ctx)
	return l2BlockNumber, l1Head
}

// waitForProposals waits until there are at least two proposals in the output oracle
// This is the minimum required for creating a game.
// Returns the l2 block number of the latest available proposal
func (h *FactoryHelper) waitForProposals(ctx context.Context) uint64 {
	ctx, cancel := context.WithTimeout(ctx, 2*time.Minute)
	defer cancel()
	latestOutputIdx := h.l2ooHelper.WaitForProposals(ctx, 2)
	return h.l2ooHelper.GetL2Output(ctx, latestOutputIdx).L2BlockNumber.Uint64()
}

// checkpointL1Block stores the current L1 block in the oracle
// Returns the L1 block number that was stored as the checkpoint
func (h *FactoryHelper) checkpointL1Block(ctx context.Context) *big.Int {
	ctx, cancel := context.WithTimeout(ctx, 1*time.Minute)
	defer cancel()
	// Store the current block in the oracle
	tx, err := h.blockOracle.Checkpoint(h.opts)
	h.require.NoError(err)
	r, err := wait.ForReceiptOK(ctx, h.client, tx.Hash())
	h.require.NoError(err, "failed to store block in block oracle")
	return new(big.Int).Sub(r.BlockNumber, big.NewInt(1))
}
