package genesis

import (
	"bytes"
	"context"
	"fmt"
	"math/rand"

	"github.com/ipfs/go-cid"
	cbor "github.com/ipfs/go-ipld-cbor"
	cbg "github.com/whyrusleeping/cbor-gen"
	"golang.org/x/xerrors"

	"github.com/filecoin-project/go-address"
	"github.com/filecoin-project/sector-storage/ffiwrapper"
	"github.com/filecoin-project/specs-actors/actors/abi"
	"github.com/filecoin-project/specs-actors/actors/abi/big"
	"github.com/filecoin-project/specs-actors/actors/builtin"
	"github.com/filecoin-project/specs-actors/actors/builtin/market"
	"github.com/filecoin-project/specs-actors/actors/builtin/miner"
	"github.com/filecoin-project/specs-actors/actors/builtin/power"
	"github.com/filecoin-project/specs-actors/actors/crypto"
	"github.com/filecoin-project/specs-actors/actors/runtime"

	"github.com/filecoin-project/lotus/chain/state"
	"github.com/filecoin-project/lotus/chain/store"
	"github.com/filecoin-project/lotus/chain/types"
	"github.com/filecoin-project/lotus/chain/vm"
	"github.com/filecoin-project/lotus/genesis"
)

func MinerAddress(genesisIndex uint64) address.Address {
	maddr, err := address.NewIDAddress(MinerStart + genesisIndex)
	if err != nil {
		panic(err)
	}

	return maddr
}

type fakedSigSyscalls struct {
	runtime.Syscalls
}

func (fss *fakedSigSyscalls) VerifySignature(signature crypto.Signature, signer address.Address, plaintext []byte) error {
	return nil
}

func SetupStorageMiners(ctx context.Context, cs *store.ChainStore, sroot cid.Cid, miners []genesis.Miner) (cid.Cid, error) {
	vm, err := vm.NewVM(sroot, 0, &fakeRand{}, cs.Blockstore(), &fakedSigSyscalls{cs.VMSys()})
	if err != nil {
		return cid.Undef, xerrors.Errorf("failed to create NewVM: %w", err)
	}

	if len(miners) == 0 {
		return cid.Undef, xerrors.New("no genesis miners")
	}

	for i, m := range miners {
		// Create miner through power actor

		spt, err := ffiwrapper.SealProofTypeFromSectorSize(m.SectorSize)
		if err != nil {
			return cid.Undef, err
		}

		var maddr address.Address
		{
			constructorParams := &power.CreateMinerParams{
				Owner:         m.Worker,
				Worker:        m.Worker,
				Peer:          m.PeerId,
				SealProofType: spt,
			}

			params := mustEnc(constructorParams)
			rval, err := doExecValue(ctx, vm, builtin.StoragePowerActorAddr, m.Owner, m.PowerBalance, builtin.MethodsPower.CreateMiner, params)
			if err != nil {
				return cid.Undef, xerrors.Errorf("failed to create genesis miner: %w", err)
			}

			var ma power.CreateMinerReturn
			if err := ma.UnmarshalCBOR(bytes.NewReader(rval)); err != nil {
				return cid.Undef, xerrors.Errorf("unmarshaling CreateMinerReturn: %w", err)
			}

			expma := MinerAddress(uint64(i))
			if ma.IDAddress != expma {
				return cid.Undef, xerrors.Errorf("miner assigned wrong address: %s != %s", ma.IDAddress, expma)
			}
			maddr = ma.IDAddress
		}

		// Add market funds

		{
			params := mustEnc(&maddr)
			_, err := doExecValue(ctx, vm, builtin.StorageMarketActorAddr, m.Worker, m.MarketBalance, builtin.MethodsMarket.AddBalance, params)
			if err != nil {
				return cid.Undef, xerrors.Errorf("failed to create genesis miner: %w", err)
			}
		}
		{
			params := mustEnc(&m.Worker)
			_, err := doExecValue(ctx, vm, builtin.StorageMarketActorAddr, m.Worker, big.Zero(), builtin.MethodsMarket.AddBalance, params)
			if err != nil {
				return cid.Undef, xerrors.Errorf("failed to create genesis miner: %w", err)
			}
		}

		// Publish preseal deals

		var dealIDs []abi.DealID
		{
			publish := func(params *market.PublishStorageDealsParams) error {
				fmt.Printf("publishing %d storage deals on miner %s with worker %s\n", len(params.Deals), params.Deals[0].Proposal.Provider, m.Worker)

				ret, err := doExecValue(ctx, vm, builtin.StorageMarketActorAddr, m.Worker, big.Zero(), builtin.MethodsMarket.PublishStorageDeals, mustEnc(params))
				if err != nil {
					return xerrors.Errorf("failed to create genesis miner: %w", err)
				}
				var ids market.PublishStorageDealsReturn
				if err := ids.UnmarshalCBOR(bytes.NewReader(ret)); err != nil {
					return xerrors.Errorf("unmarsahling publishStorageDeals result: %w", err)
				}

				dealIDs = append(dealIDs, ids.IDs...)
				return nil
			}

			params := &market.PublishStorageDealsParams{}
			for _, preseal := range m.Sectors {
				params.Deals = append(params.Deals, market.ClientDealProposal{
					Proposal:        preseal.Deal,
					ClientSignature: crypto.Signature{Type: crypto.SigTypeBLS}, // TODO: do we want to sign these? Or do we want to fake signatures for genesis setup?
				})

				if len(params.Deals) == cbg.MaxLength {
					if err := publish(params); err != nil {
						return cid.Undef, err
					}

					params = &market.PublishStorageDealsParams{}
				}
			}

			if len(params.Deals) > 0 {
				if err := publish(params); err != nil {
					return cid.Undef, err
				}
			}
		}

		// Commit sectors
		for pi, preseal := range m.Sectors {
			// TODO: Maybe check seal (Can just be snark inputs, doesn't go into the genesis file)

			// check deals, get dealWeight
			var dealWeight market.VerifyDealsOnSectorProveCommitReturn
			{
				params := &market.VerifyDealsOnSectorProveCommitParams{
					DealIDs:      []abi.DealID{dealIDs[pi]},
					SectorExpiry: preseal.Deal.EndEpoch,
				}

				ret, err := doExecValue(ctx, vm, builtin.StorageMarketActorAddr, maddr, big.Zero(), builtin.MethodsMarket.VerifyDealsOnSectorProveCommit, mustEnc(params))
				if err != nil {
					return cid.Undef, xerrors.Errorf("failed to verify preseal deals miner: %w", err)
				}
				if err := dealWeight.UnmarshalCBOR(bytes.NewReader(ret)); err != nil {
					return cid.Undef, xerrors.Errorf("unmarshaling market onProveCommit result: %w", err)
				}
			}

			// update power claims
			{
				err = vm.MutateState(ctx, builtin.StoragePowerActorAddr, func(cst cbor.IpldStore, st *power.State) error {
					weight := &power.SectorStorageWeightDesc{
						SectorSize:         m.SectorSize,
						Duration:           preseal.Deal.Duration(),
						DealWeight:         dealWeight.DealWeight,
						VerifiedDealWeight: dealWeight.VerifiedDealWeight,
					}

					qapower := power.QAPowerForWeight(weight)

					err := st.AddToClaim(&state.AdtStore{cst}, maddr, types.NewInt(uint64(weight.SectorSize)), qapower)
					if err != nil {
						return xerrors.Errorf("add to claim: %w", err)
					}
					fmt.Println("Added weight to claim: ", st.TotalRawBytePower, st.TotalQualityAdjPower)
					return nil
				})
				if err != nil {
					return cid.Undef, xerrors.Errorf("register power claim in power actor: %w", err)
				}
			}

			// Put sectors to miner sector sets
			{
				newSectorInfo := &miner.SectorOnChainInfo{
					Info: miner.SectorPreCommitInfo{
						RegisteredProof: preseal.ProofType,
						SectorNumber:    preseal.SectorID,
						SealedCID:       preseal.CommR,
						SealRandEpoch:   0,
						DealIDs:         []abi.DealID{dealIDs[pi]},
						Expiration:      preseal.Deal.EndEpoch,
					},
					ActivationEpoch:    0,
					DealWeight:         dealWeight.DealWeight,
					VerifiedDealWeight: dealWeight.VerifiedDealWeight,
				}

				err = vm.MutateState(ctx, maddr, func(cst cbor.IpldStore, st *miner.State) error {
					store := &state.AdtStore{cst}

					if err = st.PutSector(store, newSectorInfo); err != nil {
						return xerrors.Errorf("failed to put sector: %v", err)
					}

					if err := st.AddNewSectors(newSectorInfo.Info.SectorNumber); err != nil {
						return xerrors.Errorf("failed to add NewSector: %w", err)
					}

					return nil
				})
				if err != nil {
					return cid.Cid{}, xerrors.Errorf("put to sset: %w", err)
				}
			}
		}

	}

	// TODO: to avoid division by zero, we set the initial power actor power to 1, this adjusts that back down so the accounting is accurate.
	err = vm.MutateState(ctx, builtin.StoragePowerActorAddr, func(cst cbor.IpldStore, st *power.State) error {
		st.TotalQualityAdjPower = big.Sub(st.TotalQualityAdjPower, big.NewInt(1))
		return nil
	})

	c, err := vm.Flush(ctx)
	if err != nil {
		return cid.Undef, xerrors.Errorf("flushing vm: %w", err)
	}
	return c, nil
}

// TODO: copied from actors test harness, deduplicate or remove from here
type fakeRand struct{}

func (fr *fakeRand) GetRandomness(ctx context.Context, personalization crypto.DomainSeparationTag, randEpoch abi.ChainEpoch, entropy []byte) ([]byte, error) {
	out := make([]byte, 32)
	_, _ = rand.New(rand.NewSource(int64(randEpoch))).Read(out)
	return out, nil
}