package stmgr

import (
	"context"
	"errors"
	"fmt"
	"sync"
	"sync/atomic"

	"github.com/filecoin-project/lotus/chain/actors/policy"

	"github.com/ipfs/go-cid"
	cbor "github.com/ipfs/go-ipld-cbor"
	logging "github.com/ipfs/go-log/v2"
	cbg "github.com/whyrusleeping/cbor-gen"
	"go.opencensus.io/stats"
	"go.opencensus.io/trace"
	"golang.org/x/xerrors"

	"github.com/filecoin-project/go-address"
	"github.com/filecoin-project/go-state-types/abi"
	"github.com/filecoin-project/go-state-types/big"
	"github.com/filecoin-project/go-state-types/network"

	// Used for genesis.
	msig0 "github.com/filecoin-project/specs-actors/actors/builtin/multisig"
	"github.com/filecoin-project/specs-actors/v3/actors/migration/nv10"

	// we use the same adt for all receipts
	blockadt "github.com/filecoin-project/specs-actors/actors/util/adt"

	"github.com/filecoin-project/lotus/api"
	"github.com/filecoin-project/lotus/build"
	"github.com/filecoin-project/lotus/chain/actors"
	"github.com/filecoin-project/lotus/chain/actors/adt"
	"github.com/filecoin-project/lotus/chain/actors/builtin"
	"github.com/filecoin-project/lotus/chain/actors/builtin/cron"
	_init "github.com/filecoin-project/lotus/chain/actors/builtin/init"
	"github.com/filecoin-project/lotus/chain/actors/builtin/market"
	"github.com/filecoin-project/lotus/chain/actors/builtin/miner"
	"github.com/filecoin-project/lotus/chain/actors/builtin/multisig"
	"github.com/filecoin-project/lotus/chain/actors/builtin/paych"
	"github.com/filecoin-project/lotus/chain/actors/builtin/power"
	"github.com/filecoin-project/lotus/chain/actors/builtin/reward"
	"github.com/filecoin-project/lotus/chain/actors/builtin/verifreg"
	"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/metrics"
)

const LookbackNoLimit = api.LookbackNoLimit
const ReceiptAmtBitwidth = 3

var log = logging.Logger("statemgr")

type StateManagerAPI interface {
	Call(ctx context.Context, msg *types.Message, ts *types.TipSet) (*api.InvocResult, error)
	GetPaychState(ctx context.Context, addr address.Address, ts *types.TipSet) (*types.Actor, paych.State, error)
	LoadActorTsk(ctx context.Context, addr address.Address, tsk types.TipSetKey) (*types.Actor, error)
	LookupID(ctx context.Context, addr address.Address, ts *types.TipSet) (address.Address, error)
	ResolveToKeyAddress(ctx context.Context, addr address.Address, ts *types.TipSet) (address.Address, error)
}

type versionSpec struct {
	networkVersion network.Version
	atOrBelow      abi.ChainEpoch
}

type migration struct {
	upgrade       MigrationFunc
	preMigrations []PreMigration
	cache         *nv10.MemMigrationCache
}

type StateManager struct {
	cs *store.ChainStore

	cancel   context.CancelFunc
	shutdown chan struct{}

	// Determines the network version at any given epoch.
	networkVersions []versionSpec
	latestVersion   network.Version

	// Maps chain epochs to migrations.
	stateMigrations map[abi.ChainEpoch]*migration
	// A set of potentially expensive/time consuming upgrades. Explicit
	// calls for, e.g., gas estimation fail against this epoch with
	// ErrExpensiveFork.
	expensiveUpgrades map[abi.ChainEpoch]struct{}

	stCache             map[string][]cid.Cid
	tCache              treeCache
	compWait            map[string]chan struct{}
	stlk                sync.Mutex
	genesisMsigLk       sync.Mutex
	newVM               func(context.Context, *vm.VMOpts) (*vm.VM, error)
	preIgnitionVesting  []msig0.State
	postIgnitionVesting []msig0.State
	postCalicoVesting   []msig0.State

	genesisPledge      abi.TokenAmount
	genesisMarketFunds abi.TokenAmount
}

// Caches a single state tree
type treeCache struct {
	root cid.Cid
	tree *state.StateTree
}

func NewStateManager(cs *store.ChainStore) *StateManager {
	sm, err := NewStateManagerWithUpgradeSchedule(cs, DefaultUpgradeSchedule())
	if err != nil {
		panic(fmt.Sprintf("default upgrade schedule is invalid: %s", err))
	}
	return sm
}

func NewStateManagerWithUpgradeSchedule(cs *store.ChainStore, us UpgradeSchedule) (*StateManager, error) {
	// If we have upgrades, make sure they're in-order and make sense.
	if err := us.Validate(); err != nil {
		return nil, err
	}

	stateMigrations := make(map[abi.ChainEpoch]*migration, len(us))
	expensiveUpgrades := make(map[abi.ChainEpoch]struct{}, len(us))
	var networkVersions []versionSpec
	lastVersion := network.Version0
	if len(us) > 0 {
		// If we have any upgrades, process them and create a version
		// schedule.
		for _, upgrade := range us {
			if upgrade.Migration != nil || upgrade.PreMigrations != nil {
				migration := &migration{
					upgrade:       upgrade.Migration,
					preMigrations: upgrade.PreMigrations,
					cache:         nv10.NewMemMigrationCache(),
				}
				stateMigrations[upgrade.Height] = migration
			}
			if upgrade.Expensive {
				expensiveUpgrades[upgrade.Height] = struct{}{}
			}
			networkVersions = append(networkVersions, versionSpec{
				networkVersion: lastVersion,
				atOrBelow:      upgrade.Height,
			})
			lastVersion = upgrade.Network
		}
	} else {
		// Otherwise, go directly to the latest version.
		lastVersion = build.NewestNetworkVersion
	}

	return &StateManager{
		networkVersions:   networkVersions,
		latestVersion:     lastVersion,
		stateMigrations:   stateMigrations,
		expensiveUpgrades: expensiveUpgrades,
		newVM:             vm.NewVM,
		cs:                cs,
		stCache:           make(map[string][]cid.Cid),
		tCache: treeCache{
			root: cid.Undef,
			tree: nil,
		},
		compWait: make(map[string]chan struct{}),
	}, nil
}

func cidsToKey(cids []cid.Cid) string {
	var out string
	for _, c := range cids {
		out += c.KeyString()
	}
	return out
}

// Start starts the state manager's optional background processes. At the moment, this schedules
// pre-migration functions to run ahead of network upgrades.
//
// This method is not safe to invoke from multiple threads or concurrently with Stop.
func (sm *StateManager) Start(context.Context) error {
	var ctx context.Context
	ctx, sm.cancel = context.WithCancel(context.Background())
	sm.shutdown = make(chan struct{})
	go sm.preMigrationWorker(ctx)
	return nil
}

// Stop starts the state manager's background processes.
//
// This method is not safe to invoke concurrently with Start.
func (sm *StateManager) Stop(ctx context.Context) error {
	if sm.cancel != nil {
		sm.cancel()
		select {
		case <-sm.shutdown:
		case <-ctx.Done():
			return ctx.Err()
		}
	}
	return nil
}

func (sm *StateManager) TipSetState(ctx context.Context, ts *types.TipSet) (st cid.Cid, rec cid.Cid, err error) {
	ctx, span := trace.StartSpan(ctx, "tipSetState")
	defer span.End()
	if span.IsRecordingEvents() {
		span.AddAttributes(trace.StringAttribute("tipset", fmt.Sprint(ts.Cids())))
	}

	ck := cidsToKey(ts.Cids())
	sm.stlk.Lock()
	cw, cwok := sm.compWait[ck]
	if cwok {
		sm.stlk.Unlock()
		span.AddAttributes(trace.BoolAttribute("waited", true))
		select {
		case <-cw:
			sm.stlk.Lock()
		case <-ctx.Done():
			return cid.Undef, cid.Undef, ctx.Err()
		}
	}
	cached, ok := sm.stCache[ck]
	if ok {
		sm.stlk.Unlock()
		span.AddAttributes(trace.BoolAttribute("cache", true))
		return cached[0], cached[1], nil
	}
	ch := make(chan struct{})
	sm.compWait[ck] = ch

	defer func() {
		sm.stlk.Lock()
		delete(sm.compWait, ck)
		if st != cid.Undef {
			sm.stCache[ck] = []cid.Cid{st, rec}
		}
		sm.stlk.Unlock()
		close(ch)
	}()

	sm.stlk.Unlock()

	if ts.Height() == 0 {
		// NB: This is here because the process that executes blocks requires that the
		// block miner reference a valid miner in the state tree. Unless we create some
		// magical genesis miner, this won't work properly, so we short circuit here
		// This avoids the question of 'who gets paid the genesis block reward'
		return ts.Blocks()[0].ParentStateRoot, ts.Blocks()[0].ParentMessageReceipts, nil
	}

	st, rec, err = sm.computeTipSetState(ctx, ts, nil)
	if err != nil {
		return cid.Undef, cid.Undef, err
	}

	return st, rec, nil
}

func traceFunc(trace *[]*api.InvocResult) func(mcid cid.Cid, msg *types.Message, ret *vm.ApplyRet) error {
	return func(mcid cid.Cid, msg *types.Message, ret *vm.ApplyRet) error {
		ir := &api.InvocResult{
			MsgCid:         mcid,
			Msg:            msg,
			MsgRct:         &ret.MessageReceipt,
			ExecutionTrace: ret.ExecutionTrace,
			Duration:       ret.Duration,
		}
		if ret.ActorErr != nil {
			ir.Error = ret.ActorErr.Error()
		}
		if ret.GasCosts != nil {
			ir.GasCost = MakeMsgGasCost(msg, ret)
		}
		*trace = append(*trace, ir)
		return nil
	}
}

func (sm *StateManager) ExecutionTrace(ctx context.Context, ts *types.TipSet) (cid.Cid, []*api.InvocResult, error) {
	var trace []*api.InvocResult
	st, _, err := sm.computeTipSetState(ctx, ts, traceFunc(&trace))
	if err != nil {
		return cid.Undef, nil, err
	}

	return st, trace, nil
}

type ExecCallback func(cid.Cid, *types.Message, *vm.ApplyRet) error

func (sm *StateManager) ApplyBlocks(ctx context.Context, parentEpoch abi.ChainEpoch, pstate cid.Cid, bms []store.BlockMessages, epoch abi.ChainEpoch, r vm.Rand, cb ExecCallback, baseFee abi.TokenAmount, ts *types.TipSet) (cid.Cid, cid.Cid, error) {
	done := metrics.Timer(ctx, metrics.VMApplyBlocksTotal)
	defer done()

	partDone := metrics.Timer(ctx, metrics.VMApplyEarly)
	defer func() {
		partDone()
	}()

	makeVmWithBaseState := func(base cid.Cid) (*vm.VM, error) {
		vmopt := &vm.VMOpts{
			StateBase:      base,
			Epoch:          epoch,
			Rand:           r,
			Bstore:         sm.cs.StateBlockstore(),
			Syscalls:       sm.cs.VMSys(),
			CircSupplyCalc: sm.GetVMCirculatingSupply,
			NtwkVersion:    sm.GetNtwkVersion,
			BaseFee:        baseFee,
			LookbackState:  LookbackStateGetterForTipset(sm, ts),
		}

		return sm.newVM(ctx, vmopt)
	}

	vmi, err := makeVmWithBaseState(pstate)
	if err != nil {
		return cid.Undef, cid.Undef, xerrors.Errorf("making vm: %w", err)
	}

	runCron := func(epoch abi.ChainEpoch) error {
		cronMsg := &types.Message{
			To:         cron.Address,
			From:       builtin.SystemActorAddr,
			Nonce:      uint64(epoch),
			Value:      types.NewInt(0),
			GasFeeCap:  types.NewInt(0),
			GasPremium: types.NewInt(0),
			GasLimit:   build.BlockGasLimit * 10000, // Make super sure this is never too little
			Method:     cron.Methods.EpochTick,
			Params:     nil,
		}
		ret, err := vmi.ApplyImplicitMessage(ctx, cronMsg)
		if err != nil {
			return err
		}
		if cb != nil {
			if err := cb(cronMsg.Cid(), cronMsg, ret); err != nil {
				return xerrors.Errorf("callback failed on cron message: %w", err)
			}
		}
		if ret.ExitCode != 0 {
			return xerrors.Errorf("CheckProofSubmissions exit was non-zero: %d", ret.ExitCode)
		}

		return nil
	}

	for i := parentEpoch; i < epoch; i++ {
		if i > parentEpoch {
			// run cron for null rounds if any
			if err := runCron(i); err != nil {
				return cid.Undef, cid.Undef, err
			}

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

		// handle state forks
		// XXX: The state tree
		newState, err := sm.handleStateForks(ctx, pstate, i, cb, ts)
		if err != nil {
			return cid.Undef, cid.Undef, xerrors.Errorf("error handling state forks: %w", err)
		}

		if pstate != newState {
			vmi, err = makeVmWithBaseState(newState)
			if err != nil {
				return cid.Undef, cid.Undef, xerrors.Errorf("making vm: %w", err)
			}
		}

		vmi.SetBlockHeight(i + 1)
		pstate = newState
	}

	partDone()
	partDone = metrics.Timer(ctx, metrics.VMApplyMessages)

	var receipts []cbg.CBORMarshaler
	processedMsgs := make(map[cid.Cid]struct{})
	for _, b := range bms {
		penalty := types.NewInt(0)
		gasReward := big.Zero()

		for _, cm := range append(b.BlsMessages, b.SecpkMessages...) {
			m := cm.VMMessage()
			if _, found := processedMsgs[m.Cid()]; found {
				continue
			}
			r, err := vmi.ApplyMessage(ctx, cm)
			if err != nil {
				return cid.Undef, cid.Undef, err
			}

			receipts = append(receipts, &r.MessageReceipt)
			gasReward = big.Add(gasReward, r.GasCosts.MinerTip)
			penalty = big.Add(penalty, r.GasCosts.MinerPenalty)

			if cb != nil {
				if err := cb(cm.Cid(), m, r); err != nil {
					return cid.Undef, cid.Undef, err
				}
			}
			processedMsgs[m.Cid()] = struct{}{}
		}

		params, err := actors.SerializeParams(&reward.AwardBlockRewardParams{
			Miner:     b.Miner,
			Penalty:   penalty,
			GasReward: gasReward,
			WinCount:  b.WinCount,
		})
		if err != nil {
			return cid.Undef, cid.Undef, xerrors.Errorf("failed to serialize award params: %w", err)
		}

		rwMsg := &types.Message{
			From:       builtin.SystemActorAddr,
			To:         reward.Address,
			Nonce:      uint64(epoch),
			Value:      types.NewInt(0),
			GasFeeCap:  types.NewInt(0),
			GasPremium: types.NewInt(0),
			GasLimit:   1 << 30,
			Method:     reward.Methods.AwardBlockReward,
			Params:     params,
		}
		ret, actErr := vmi.ApplyImplicitMessage(ctx, rwMsg)
		if actErr != nil {
			return cid.Undef, cid.Undef, xerrors.Errorf("failed to apply reward message for miner %s: %w", b.Miner, actErr)
		}
		if cb != nil {
			if err := cb(rwMsg.Cid(), rwMsg, ret); err != nil {
				return cid.Undef, cid.Undef, xerrors.Errorf("callback failed on reward message: %w", err)
			}
		}

		if ret.ExitCode != 0 {
			return cid.Undef, cid.Undef, xerrors.Errorf("reward application message failed (exit %d): %s", ret.ExitCode, ret.ActorErr)
		}
	}

	partDone()
	partDone = metrics.Timer(ctx, metrics.VMApplyCron)

	if err := runCron(epoch); err != nil {
		return cid.Cid{}, cid.Cid{}, err
	}

	partDone()
	partDone = metrics.Timer(ctx, metrics.VMApplyFlush)

	rectarr := blockadt.MakeEmptyArray(sm.cs.ActorStore(ctx))
	for i, receipt := range receipts {
		if err := rectarr.Set(uint64(i), receipt); err != nil {
			return cid.Undef, cid.Undef, xerrors.Errorf("failed to build receipts amt: %w", err)
		}
	}
	rectroot, err := rectarr.Root()
	if err != nil {
		return cid.Undef, cid.Undef, xerrors.Errorf("failed to build receipts amt: %w", err)
	}

	st, err := vmi.Flush(ctx)
	if err != nil {
		return cid.Undef, cid.Undef, xerrors.Errorf("vm flush failed: %w", err)
	}

	stats.Record(ctx, metrics.VMSends.M(int64(atomic.LoadUint64(&vm.StatSends))),
		metrics.VMApplied.M(int64(atomic.LoadUint64(&vm.StatApplied))))

	return st, rectroot, nil
}

func (sm *StateManager) computeTipSetState(ctx context.Context, ts *types.TipSet, cb ExecCallback) (cid.Cid, cid.Cid, error) {
	ctx, span := trace.StartSpan(ctx, "computeTipSetState")
	defer span.End()

	blks := ts.Blocks()

	for i := 0; i < len(blks); i++ {
		for j := i + 1; j < len(blks); j++ {
			if blks[i].Miner == blks[j].Miner {
				return cid.Undef, cid.Undef,
					xerrors.Errorf("duplicate miner in a tipset (%s %s)",
						blks[i].Miner, blks[j].Miner)
			}
		}
	}

	var parentEpoch abi.ChainEpoch
	pstate := blks[0].ParentStateRoot
	if blks[0].Height > 0 {
		parent, err := sm.cs.GetBlock(blks[0].Parents[0])
		if err != nil {
			return cid.Undef, cid.Undef, xerrors.Errorf("getting parent block: %w", err)
		}

		parentEpoch = parent.Height
	}

	r := store.NewChainRand(sm.cs, ts.Cids())

	blkmsgs, err := sm.cs.BlockMsgsForTipset(ts)
	if err != nil {
		return cid.Undef, cid.Undef, xerrors.Errorf("getting block messages for tipset: %w", err)
	}

	baseFee := blks[0].ParentBaseFee

	return sm.ApplyBlocks(ctx, parentEpoch, pstate, blkmsgs, blks[0].Height, r, cb, baseFee, ts)
}

func (sm *StateManager) parentState(ts *types.TipSet) cid.Cid {
	if ts == nil {
		ts = sm.cs.GetHeaviestTipSet()
	}

	return ts.ParentState()
}

func (sm *StateManager) ChainStore() *store.ChainStore {
	return sm.cs
}

// ResolveToKeyAddress is similar to `vm.ResolveToKeyAddr` but does not allow `Actor` type of addresses.
// Uses the `TipSet` `ts` to generate the VM state.
func (sm *StateManager) ResolveToKeyAddress(ctx context.Context, addr address.Address, ts *types.TipSet) (address.Address, error) {
	switch addr.Protocol() {
	case address.BLS, address.SECP256K1:
		return addr, nil
	case address.Actor:
		return address.Undef, xerrors.New("cannot resolve actor address to key address")
	default:
	}

	if ts == nil {
		ts = sm.cs.GetHeaviestTipSet()
	}

	cst := cbor.NewCborStore(sm.cs.StateBlockstore())

	// First try to resolve the actor in the parent state, so we don't have to compute anything.
	tree, err := state.LoadStateTree(cst, ts.ParentState())
	if err != nil {
		return address.Undef, xerrors.Errorf("failed to load parent state tree: %w", err)
	}

	resolved, err := vm.ResolveToKeyAddr(tree, cst, addr)
	if err == nil {
		return resolved, nil
	}

	// If that fails, compute the tip-set and try again.
	st, _, err := sm.TipSetState(ctx, ts)
	if err != nil {
		return address.Undef, xerrors.Errorf("resolve address failed to get tipset state: %w", err)
	}

	tree, err = state.LoadStateTree(cst, st)
	if err != nil {
		return address.Undef, xerrors.Errorf("failed to load state tree")
	}

	return vm.ResolveToKeyAddr(tree, cst, addr)
}

// ResolveToKeyAddressAtFinality is similar to stmgr.ResolveToKeyAddress but fails if the ID address being resolved isn't reorg-stable yet.
// It should not be used for consensus-critical subsystems.
func (sm *StateManager) ResolveToKeyAddressAtFinality(ctx context.Context, addr address.Address, ts *types.TipSet) (address.Address, error) {
	switch addr.Protocol() {
	case address.BLS, address.SECP256K1:
		return addr, nil
	case address.Actor:
		return address.Undef, xerrors.New("cannot resolve actor address to key address")
	default:
	}

	if ts == nil {
		ts = sm.cs.GetHeaviestTipSet()
	}

	var err error
	if ts.Height() > policy.ChainFinality {
		ts, err = sm.ChainStore().GetTipsetByHeight(ctx, ts.Height()-policy.ChainFinality, ts, true)
		if err != nil {
			return address.Undef, xerrors.Errorf("failed to load lookback tipset: %w", err)
		}
	}

	cst := cbor.NewCborStore(sm.cs.StateBlockstore())
	tree := sm.tCache.tree

	if tree == nil || sm.tCache.root != ts.ParentState() {
		tree, err = state.LoadStateTree(cst, ts.ParentState())
		if err != nil {
			return address.Undef, xerrors.Errorf("failed to load parent state tree: %w", err)
		}

		sm.tCache = treeCache{
			root: ts.ParentState(),
			tree: tree,
		}
	}

	resolved, err := vm.ResolveToKeyAddr(tree, cst, addr)
	if err == nil {
		return resolved, nil
	}

	return address.Undef, xerrors.New("ID address not found in lookback state")
}

func (sm *StateManager) GetBlsPublicKey(ctx context.Context, addr address.Address, ts *types.TipSet) (pubk []byte, err error) {
	kaddr, err := sm.ResolveToKeyAddress(ctx, addr, ts)
	if err != nil {
		return pubk, xerrors.Errorf("failed to resolve address to key address: %w", err)
	}

	if kaddr.Protocol() != address.BLS {
		return pubk, xerrors.Errorf("address must be BLS address to load bls public key")
	}

	return kaddr.Payload(), nil
}

func (sm *StateManager) LookupID(ctx context.Context, addr address.Address, ts *types.TipSet) (address.Address, error) {
	cst := cbor.NewCborStore(sm.cs.StateBlockstore())
	state, err := state.LoadStateTree(cst, sm.parentState(ts))
	if err != nil {
		return address.Undef, xerrors.Errorf("load state tree: %w", err)
	}
	return state.LookupID(addr)
}

// WaitForMessage blocks until a message appears on chain. It looks backwards in the chain to see if this has already
// happened, with an optional limit to how many epochs it will search. It guarantees that the message has been on
// chain for at least confidence epochs without being reverted before returning.
func (sm *StateManager) WaitForMessage(ctx context.Context, mcid cid.Cid, confidence uint64, lookbackLimit abi.ChainEpoch, allowReplaced bool) (*types.TipSet, *types.MessageReceipt, cid.Cid, error) {
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	msg, err := sm.cs.GetCMessage(mcid)
	if err != nil {
		return nil, nil, cid.Undef, fmt.Errorf("failed to load message: %w", err)
	}

	tsub := sm.cs.SubHeadChanges(ctx)

	head, ok := <-tsub
	if !ok {
		return nil, nil, cid.Undef, fmt.Errorf("SubHeadChanges stream was invalid")
	}

	if len(head) != 1 {
		return nil, nil, cid.Undef, fmt.Errorf("SubHeadChanges first entry should have been one item")
	}

	if head[0].Type != store.HCCurrent {
		return nil, nil, cid.Undef, fmt.Errorf("expected current head on SHC stream (got %s)", head[0].Type)
	}

	r, foundMsg, err := sm.tipsetExecutedMessage(head[0].Val, mcid, msg.VMMessage(), allowReplaced)
	if err != nil {
		return nil, nil, cid.Undef, err
	}

	if r != nil {
		return head[0].Val, r, foundMsg, nil
	}

	var backTs *types.TipSet
	var backRcp *types.MessageReceipt
	var backFm cid.Cid
	backSearchWait := make(chan struct{})
	go func() {
		fts, r, foundMsg, err := sm.searchBackForMsg(ctx, head[0].Val, msg, lookbackLimit, allowReplaced)
		if err != nil {
			log.Warnf("failed to look back through chain for message: %v", err)
			return
		}

		backTs = fts
		backRcp = r
		backFm = foundMsg
		close(backSearchWait)
	}()

	var candidateTs *types.TipSet
	var candidateRcp *types.MessageReceipt
	var candidateFm cid.Cid
	heightOfHead := head[0].Val.Height()
	reverts := map[types.TipSetKey]bool{}

	for {
		select {
		case notif, ok := <-tsub:
			if !ok {
				return nil, nil, cid.Undef, ctx.Err()
			}
			for _, val := range notif {
				switch val.Type {
				case store.HCRevert:
					if val.Val.Equals(candidateTs) {
						candidateTs = nil
						candidateRcp = nil
						candidateFm = cid.Undef
					}
					if backSearchWait != nil {
						reverts[val.Val.Key()] = true
					}
				case store.HCApply:
					if candidateTs != nil && val.Val.Height() >= candidateTs.Height()+abi.ChainEpoch(confidence) {
						return candidateTs, candidateRcp, candidateFm, nil
					}
					r, foundMsg, err := sm.tipsetExecutedMessage(val.Val, mcid, msg.VMMessage(), allowReplaced)
					if err != nil {
						return nil, nil, cid.Undef, err
					}
					if r != nil {
						if confidence == 0 {
							return val.Val, r, foundMsg, err
						}
						candidateTs = val.Val
						candidateRcp = r
						candidateFm = foundMsg
					}
					heightOfHead = val.Val.Height()
				}
			}
		case <-backSearchWait:
			// check if we found the message in the chain and that is hasn't been reverted since we started searching
			if backTs != nil && !reverts[backTs.Key()] {
				// if head is at or past confidence interval, return immediately
				if heightOfHead >= backTs.Height()+abi.ChainEpoch(confidence) {
					return backTs, backRcp, backFm, nil
				}

				// wait for confidence interval
				candidateTs = backTs
				candidateRcp = backRcp
				candidateFm = backFm
			}
			reverts = nil
			backSearchWait = nil
		case <-ctx.Done():
			return nil, nil, cid.Undef, ctx.Err()
		}
	}
}

func (sm *StateManager) SearchForMessage(ctx context.Context, head *types.TipSet, mcid cid.Cid, lookbackLimit abi.ChainEpoch, allowReplaced bool) (*types.TipSet, *types.MessageReceipt, cid.Cid, error) {
	msg, err := sm.cs.GetCMessage(mcid)
	if err != nil {
		return nil, nil, cid.Undef, fmt.Errorf("failed to load message: %w", err)
	}

	r, foundMsg, err := sm.tipsetExecutedMessage(head, mcid, msg.VMMessage(), allowReplaced)
	if err != nil {
		return nil, nil, cid.Undef, err
	}

	if r != nil {
		return head, r, foundMsg, nil
	}

	fts, r, foundMsg, err := sm.searchBackForMsg(ctx, head, msg, lookbackLimit, allowReplaced)

	if err != nil {
		log.Warnf("failed to look back through chain for message %s", mcid)
		return nil, nil, cid.Undef, err
	}

	if fts == nil {
		return nil, nil, cid.Undef, nil
	}

	return fts, r, foundMsg, nil
}

// searchBackForMsg searches up to limit tipsets backwards from the given
// tipset for a message receipt.
// If limit is
// - 0 then no tipsets are searched
// - 5 then five tipset are searched
// - LookbackNoLimit then there is no limit
func (sm *StateManager) searchBackForMsg(ctx context.Context, from *types.TipSet, m types.ChainMsg, limit abi.ChainEpoch, allowReplaced bool) (*types.TipSet, *types.MessageReceipt, cid.Cid, error) {
	limitHeight := from.Height() - limit
	noLimit := limit == LookbackNoLimit

	cur := from
	curActor, err := sm.LoadActor(ctx, m.VMMessage().From, cur)
	if err != nil {
		return nil, nil, cid.Undef, xerrors.Errorf("failed to load initital tipset")
	}

	mFromId, err := sm.LookupID(ctx, m.VMMessage().From, from)
	if err != nil {
		return nil, nil, cid.Undef, xerrors.Errorf("looking up From id address: %w", err)
	}

	mNonce := m.VMMessage().Nonce

	for {
		// If we've reached the genesis block, or we've reached the limit of
		// how far back to look
		if cur.Height() == 0 || !noLimit && cur.Height() <= limitHeight {
			// it ain't here!
			return nil, nil, cid.Undef, nil
		}

		select {
		case <-ctx.Done():
			return nil, nil, cid.Undef, nil
		default:
		}

		// we either have no messages from the sender, or the latest message we found has a lower nonce than the one being searched for,
		// either way, no reason to lookback, it ain't there
		if curActor == nil || curActor.Nonce == 0 || curActor.Nonce < mNonce {
			return nil, nil, cid.Undef, nil
		}

		pts, err := sm.cs.LoadTipSet(cur.Parents())
		if err != nil {
			return nil, nil, cid.Undef, xerrors.Errorf("failed to load tipset during msg wait searchback: %w", err)
		}

		act, err := sm.LoadActor(ctx, mFromId, pts)
		actorNoExist := errors.Is(err, types.ErrActorNotFound)
		if err != nil && !actorNoExist {
			return nil, nil, cid.Cid{}, xerrors.Errorf("failed to load the actor: %w", err)
		}

		// check that between cur and parent tipset the nonce fell into range of our message
		if actorNoExist || (curActor.Nonce > mNonce && act.Nonce <= mNonce) {
			r, foundMsg, err := sm.tipsetExecutedMessage(cur, m.Cid(), m.VMMessage(), allowReplaced)
			if err != nil {
				return nil, nil, cid.Undef, xerrors.Errorf("checking for message execution during lookback: %w", err)
			}

			if r != nil {
				return cur, r, foundMsg, nil
			}
		}

		cur = pts
		curActor = act
	}
}

func (sm *StateManager) tipsetExecutedMessage(ts *types.TipSet, msg cid.Cid, vmm *types.Message, allowReplaced bool) (*types.MessageReceipt, cid.Cid, error) {
	// The genesis block did not execute any messages
	if ts.Height() == 0 {
		return nil, cid.Undef, nil
	}

	pts, err := sm.cs.LoadTipSet(ts.Parents())
	if err != nil {
		return nil, cid.Undef, err
	}

	cm, err := sm.cs.MessagesForTipset(pts)
	if err != nil {
		return nil, cid.Undef, err
	}

	for ii := range cm {
		// iterate in reverse because we going backwards through the chain
		i := len(cm) - ii - 1
		m := cm[i]

		if m.VMMessage().From == vmm.From { // cheaper to just check origin first
			if m.VMMessage().Nonce == vmm.Nonce {
				if allowReplaced && m.VMMessage().EqualCall(vmm) {
					if m.Cid() != msg {
						log.Warnw("found message with equal nonce and call params but different CID",
							"wanted", msg, "found", m.Cid(), "nonce", vmm.Nonce, "from", vmm.From)
					}

					pr, err := sm.cs.GetParentReceipt(ts.Blocks()[0], i)
					if err != nil {
						return nil, cid.Undef, err
					}
					return pr, m.Cid(), nil
				}

				// this should be that message
				return nil, cid.Undef, xerrors.Errorf("found message with equal nonce as the one we are looking for (F:%s n %d, TS: %s n%d)",
					msg, vmm.Nonce, m.Cid(), m.VMMessage().Nonce)
			}
			if m.VMMessage().Nonce < vmm.Nonce {
				return nil, cid.Undef, nil // don't bother looking further
			}
		}
	}

	return nil, cid.Undef, nil
}

func (sm *StateManager) ListAllActors(ctx context.Context, ts *types.TipSet) ([]address.Address, error) {
	if ts == nil {
		ts = sm.cs.GetHeaviestTipSet()
	}
	st, _, err := sm.TipSetState(ctx, ts)
	if err != nil {
		return nil, err
	}

	stateTree, err := sm.StateTree(st)
	if err != nil {
		return nil, err
	}

	var out []address.Address
	err = stateTree.ForEach(func(addr address.Address, act *types.Actor) error {
		out = append(out, addr)
		return nil
	})
	if err != nil {
		return nil, err
	}

	return out, nil
}

func (sm *StateManager) MarketBalance(ctx context.Context, addr address.Address, ts *types.TipSet) (api.MarketBalance, error) {
	st, err := sm.ParentState(ts)
	if err != nil {
		return api.MarketBalance{}, err
	}

	act, err := st.GetActor(market.Address)
	if err != nil {
		return api.MarketBalance{}, err
	}

	mstate, err := market.Load(sm.cs.ActorStore(ctx), act)
	if err != nil {
		return api.MarketBalance{}, err
	}

	addr, err = sm.LookupID(ctx, addr, ts)
	if err != nil {
		return api.MarketBalance{}, err
	}

	var out api.MarketBalance

	et, err := mstate.EscrowTable()
	if err != nil {
		return api.MarketBalance{}, err
	}
	out.Escrow, err = et.Get(addr)
	if err != nil {
		return api.MarketBalance{}, xerrors.Errorf("getting escrow balance: %w", err)
	}

	lt, err := mstate.LockedTable()
	if err != nil {
		return api.MarketBalance{}, err
	}
	out.Locked, err = lt.Get(addr)
	if err != nil {
		return api.MarketBalance{}, xerrors.Errorf("getting locked balance: %w", err)
	}

	return out, nil
}

func (sm *StateManager) ValidateChain(ctx context.Context, ts *types.TipSet) error {
	tschain := []*types.TipSet{ts}
	for ts.Height() != 0 {
		next, err := sm.cs.LoadTipSet(ts.Parents())
		if err != nil {
			return err
		}

		tschain = append(tschain, next)
		ts = next
	}

	lastState := tschain[len(tschain)-1].ParentState()
	for i := len(tschain) - 1; i >= 0; i-- {
		cur := tschain[i]
		log.Infof("computing state (height: %d, ts=%s)", cur.Height(), cur.Cids())
		if cur.ParentState() != lastState {
			return xerrors.Errorf("tipset chain had state mismatch at height %d", cur.Height())
		}
		st, _, err := sm.TipSetState(ctx, cur)
		if err != nil {
			return err
		}
		lastState = st
	}

	return nil
}

func (sm *StateManager) SetVMConstructor(nvm func(context.Context, *vm.VMOpts) (*vm.VM, error)) {
	sm.newVM = nvm
}

// sets up information about the vesting schedule
func (sm *StateManager) setupGenesisVestingSchedule(ctx context.Context) error {

	gb, err := sm.cs.GetGenesis()
	if err != nil {
		return xerrors.Errorf("getting genesis block: %w", err)
	}

	gts, err := types.NewTipSet([]*types.BlockHeader{gb})
	if err != nil {
		return xerrors.Errorf("getting genesis tipset: %w", err)
	}

	st, _, err := sm.TipSetState(ctx, gts)
	if err != nil {
		return xerrors.Errorf("getting genesis tipset state: %w", err)
	}

	cst := cbor.NewCborStore(sm.cs.StateBlockstore())
	sTree, err := state.LoadStateTree(cst, st)
	if err != nil {
		return xerrors.Errorf("loading state tree: %w", err)
	}

	gmf, err := getFilMarketLocked(ctx, sTree)
	if err != nil {
		return xerrors.Errorf("setting up genesis market funds: %w", err)
	}

	gp, err := getFilPowerLocked(ctx, sTree)
	if err != nil {
		return xerrors.Errorf("setting up genesis pledge: %w", err)
	}

	sm.genesisMarketFunds = gmf
	sm.genesisPledge = gp

	totalsByEpoch := make(map[abi.ChainEpoch]abi.TokenAmount)

	// 6 months
	sixMonths := abi.ChainEpoch(183 * builtin.EpochsInDay)
	totalsByEpoch[sixMonths] = big.NewInt(49_929_341)
	totalsByEpoch[sixMonths] = big.Add(totalsByEpoch[sixMonths], big.NewInt(32_787_700))

	// 1 year
	oneYear := abi.ChainEpoch(365 * builtin.EpochsInDay)
	totalsByEpoch[oneYear] = big.NewInt(22_421_712)

	// 2 years
	twoYears := abi.ChainEpoch(2 * 365 * builtin.EpochsInDay)
	totalsByEpoch[twoYears] = big.NewInt(7_223_364)

	// 3 years
	threeYears := abi.ChainEpoch(3 * 365 * builtin.EpochsInDay)
	totalsByEpoch[threeYears] = big.NewInt(87_637_883)

	// 6 years
	sixYears := abi.ChainEpoch(6 * 365 * builtin.EpochsInDay)
	totalsByEpoch[sixYears] = big.NewInt(100_000_000)
	totalsByEpoch[sixYears] = big.Add(totalsByEpoch[sixYears], big.NewInt(300_000_000))

	sm.preIgnitionVesting = make([]msig0.State, 0, len(totalsByEpoch))
	for k, v := range totalsByEpoch {
		ns := msig0.State{
			InitialBalance: v,
			UnlockDuration: k,
			PendingTxns:    cid.Undef,
		}
		sm.preIgnitionVesting = append(sm.preIgnitionVesting, ns)
	}

	return nil
}

// sets up information about the vesting schedule post the ignition upgrade
func (sm *StateManager) setupPostIgnitionVesting(ctx context.Context) error {

	totalsByEpoch := make(map[abi.ChainEpoch]abi.TokenAmount)

	// 6 months
	sixMonths := abi.ChainEpoch(183 * builtin.EpochsInDay)
	totalsByEpoch[sixMonths] = big.NewInt(49_929_341)
	totalsByEpoch[sixMonths] = big.Add(totalsByEpoch[sixMonths], big.NewInt(32_787_700))

	// 1 year
	oneYear := abi.ChainEpoch(365 * builtin.EpochsInDay)
	totalsByEpoch[oneYear] = big.NewInt(22_421_712)

	// 2 years
	twoYears := abi.ChainEpoch(2 * 365 * builtin.EpochsInDay)
	totalsByEpoch[twoYears] = big.NewInt(7_223_364)

	// 3 years
	threeYears := abi.ChainEpoch(3 * 365 * builtin.EpochsInDay)
	totalsByEpoch[threeYears] = big.NewInt(87_637_883)

	// 6 years
	sixYears := abi.ChainEpoch(6 * 365 * builtin.EpochsInDay)
	totalsByEpoch[sixYears] = big.NewInt(100_000_000)
	totalsByEpoch[sixYears] = big.Add(totalsByEpoch[sixYears], big.NewInt(300_000_000))

	sm.postIgnitionVesting = make([]msig0.State, 0, len(totalsByEpoch))
	for k, v := range totalsByEpoch {
		ns := msig0.State{
			// In the pre-ignition logic, we incorrectly set this value in Fil, not attoFil, an off-by-10^18 error
			InitialBalance: big.Mul(v, big.NewInt(int64(build.FilecoinPrecision))),
			UnlockDuration: k,
			PendingTxns:    cid.Undef,
			// In the pre-ignition logic, the start epoch was 0. This changes in the fork logic of the Ignition upgrade itself.
			StartEpoch: build.UpgradeLiftoffHeight,
		}
		sm.postIgnitionVesting = append(sm.postIgnitionVesting, ns)
	}

	return nil
}

// sets up information about the vesting schedule post the calico upgrade
func (sm *StateManager) setupPostCalicoVesting(ctx context.Context) error {

	totalsByEpoch := make(map[abi.ChainEpoch]abi.TokenAmount)

	// 0 days
	zeroDays := abi.ChainEpoch(0)
	totalsByEpoch[zeroDays] = big.NewInt(10_632_000)

	// 6 months
	sixMonths := abi.ChainEpoch(183 * builtin.EpochsInDay)
	totalsByEpoch[sixMonths] = big.NewInt(19_015_887)
	totalsByEpoch[sixMonths] = big.Add(totalsByEpoch[sixMonths], big.NewInt(32_787_700))

	// 1 year
	oneYear := abi.ChainEpoch(365 * builtin.EpochsInDay)
	totalsByEpoch[oneYear] = big.NewInt(22_421_712)
	totalsByEpoch[oneYear] = big.Add(totalsByEpoch[oneYear], big.NewInt(9_400_000))

	// 2 years
	twoYears := abi.ChainEpoch(2 * 365 * builtin.EpochsInDay)
	totalsByEpoch[twoYears] = big.NewInt(7_223_364)

	// 3 years
	threeYears := abi.ChainEpoch(3 * 365 * builtin.EpochsInDay)
	totalsByEpoch[threeYears] = big.NewInt(87_637_883)
	totalsByEpoch[threeYears] = big.Add(totalsByEpoch[threeYears], big.NewInt(898_958))

	// 6 years
	sixYears := abi.ChainEpoch(6 * 365 * builtin.EpochsInDay)
	totalsByEpoch[sixYears] = big.NewInt(100_000_000)
	totalsByEpoch[sixYears] = big.Add(totalsByEpoch[sixYears], big.NewInt(300_000_000))
	totalsByEpoch[sixYears] = big.Add(totalsByEpoch[sixYears], big.NewInt(9_805_053))

	sm.postCalicoVesting = make([]msig0.State, 0, len(totalsByEpoch))
	for k, v := range totalsByEpoch {
		ns := msig0.State{
			InitialBalance: big.Mul(v, big.NewInt(int64(build.FilecoinPrecision))),
			UnlockDuration: k,
			PendingTxns:    cid.Undef,
			StartEpoch:     build.UpgradeLiftoffHeight,
		}
		sm.postCalicoVesting = append(sm.postCalicoVesting, ns)
	}

	return nil
}

// GetVestedFunds returns all funds that have "left" actors that are in the genesis state:
// - For Multisigs, it counts the actual amounts that have vested at the given epoch
// - For Accounts, it counts max(currentBalance - genesisBalance, 0).
func (sm *StateManager) GetFilVested(ctx context.Context, height abi.ChainEpoch, st *state.StateTree) (abi.TokenAmount, error) {
	vf := big.Zero()
	if height <= build.UpgradeIgnitionHeight {
		for _, v := range sm.preIgnitionVesting {
			au := big.Sub(v.InitialBalance, v.AmountLocked(height))
			vf = big.Add(vf, au)
		}
	} else if height <= build.UpgradeCalicoHeight {
		for _, v := range sm.postIgnitionVesting {
			// In the pre-ignition logic, we simply called AmountLocked(height), assuming startEpoch was 0.
			// The start epoch changed in the Ignition upgrade.
			au := big.Sub(v.InitialBalance, v.AmountLocked(height-v.StartEpoch))
			vf = big.Add(vf, au)
		}
	} else {
		for _, v := range sm.postCalicoVesting {
			// In the pre-ignition logic, we simply called AmountLocked(height), assuming startEpoch was 0.
			// The start epoch changed in the Ignition upgrade.
			au := big.Sub(v.InitialBalance, v.AmountLocked(height-v.StartEpoch))
			vf = big.Add(vf, au)
		}
	}

	// After UpgradeAssemblyHeight these funds are accounted for in GetFilReserveDisbursed
	if height <= build.UpgradeAssemblyHeight {
		// continue to use preIgnitionGenInfos, nothing changed at the Ignition epoch
		vf = big.Add(vf, sm.genesisPledge)
		// continue to use preIgnitionGenInfos, nothing changed at the Ignition epoch
		vf = big.Add(vf, sm.genesisMarketFunds)
	}

	return vf, nil
}

func GetFilReserveDisbursed(ctx context.Context, st *state.StateTree) (abi.TokenAmount, error) {
	ract, err := st.GetActor(builtin.ReserveAddress)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to get reserve actor: %w", err)
	}

	// If money enters the reserve actor, this could lead to a negative term
	return big.Sub(big.NewFromGo(build.InitialFilReserved), ract.Balance), nil
}

func GetFilMined(ctx context.Context, st *state.StateTree) (abi.TokenAmount, error) {
	ractor, err := st.GetActor(reward.Address)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to load reward actor state: %w", err)
	}

	rst, err := reward.Load(adt.WrapStore(ctx, st.Store), ractor)
	if err != nil {
		return big.Zero(), err
	}

	return rst.TotalStoragePowerReward()
}

func getFilMarketLocked(ctx context.Context, st *state.StateTree) (abi.TokenAmount, error) {
	act, err := st.GetActor(market.Address)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to load market actor: %w", err)
	}

	mst, err := market.Load(adt.WrapStore(ctx, st.Store), act)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to load market state: %w", err)
	}

	return mst.TotalLocked()
}

func getFilPowerLocked(ctx context.Context, st *state.StateTree) (abi.TokenAmount, error) {
	pactor, err := st.GetActor(power.Address)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to load power actor: %w", err)
	}

	pst, err := power.Load(adt.WrapStore(ctx, st.Store), pactor)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to load power state: %w", err)
	}

	return pst.TotalLocked()
}

func (sm *StateManager) GetFilLocked(ctx context.Context, st *state.StateTree) (abi.TokenAmount, error) {

	filMarketLocked, err := getFilMarketLocked(ctx, st)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to get filMarketLocked: %w", err)
	}

	filPowerLocked, err := getFilPowerLocked(ctx, st)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to get filPowerLocked: %w", err)
	}

	return types.BigAdd(filMarketLocked, filPowerLocked), nil
}

func GetFilBurnt(ctx context.Context, st *state.StateTree) (abi.TokenAmount, error) {
	burnt, err := st.GetActor(builtin.BurntFundsActorAddr)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to load burnt actor: %w", err)
	}

	return burnt.Balance, nil
}

func (sm *StateManager) GetVMCirculatingSupply(ctx context.Context, height abi.ChainEpoch, st *state.StateTree) (abi.TokenAmount, error) {
	cs, err := sm.GetVMCirculatingSupplyDetailed(ctx, height, st)
	if err != nil {
		return types.EmptyInt, err
	}

	return cs.FilCirculating, err
}

func (sm *StateManager) GetVMCirculatingSupplyDetailed(ctx context.Context, height abi.ChainEpoch, st *state.StateTree) (api.CirculatingSupply, error) {
	sm.genesisMsigLk.Lock()
	defer sm.genesisMsigLk.Unlock()
	if sm.preIgnitionVesting == nil || sm.genesisPledge.IsZero() || sm.genesisMarketFunds.IsZero() {
		err := sm.setupGenesisVestingSchedule(ctx)
		if err != nil {
			return api.CirculatingSupply{}, xerrors.Errorf("failed to setup pre-ignition vesting schedule: %w", err)
		}
	}
	if sm.postIgnitionVesting == nil {
		err := sm.setupPostIgnitionVesting(ctx)
		if err != nil {
			return api.CirculatingSupply{}, xerrors.Errorf("failed to setup post-ignition vesting schedule: %w", err)
		}
	}
	if sm.postCalicoVesting == nil {
		err := sm.setupPostCalicoVesting(ctx)
		if err != nil {
			return api.CirculatingSupply{}, xerrors.Errorf("failed to setup post-calico vesting schedule: %w", err)
		}
	}

	filVested, err := sm.GetFilVested(ctx, height, st)
	if err != nil {
		return api.CirculatingSupply{}, xerrors.Errorf("failed to calculate filVested: %w", err)
	}

	filReserveDisbursed := big.Zero()
	if height > build.UpgradeAssemblyHeight {
		filReserveDisbursed, err = GetFilReserveDisbursed(ctx, st)
		if err != nil {
			return api.CirculatingSupply{}, xerrors.Errorf("failed to calculate filReserveDisbursed: %w", err)
		}
	}

	filMined, err := GetFilMined(ctx, st)
	if err != nil {
		return api.CirculatingSupply{}, xerrors.Errorf("failed to calculate filMined: %w", err)
	}

	filBurnt, err := GetFilBurnt(ctx, st)
	if err != nil {
		return api.CirculatingSupply{}, xerrors.Errorf("failed to calculate filBurnt: %w", err)
	}

	filLocked, err := sm.GetFilLocked(ctx, st)
	if err != nil {
		return api.CirculatingSupply{}, xerrors.Errorf("failed to calculate filLocked: %w", err)
	}

	ret := types.BigAdd(filVested, filMined)
	ret = types.BigAdd(ret, filReserveDisbursed)
	ret = types.BigSub(ret, filBurnt)
	ret = types.BigSub(ret, filLocked)

	if ret.LessThan(big.Zero()) {
		ret = big.Zero()
	}

	return api.CirculatingSupply{
		FilVested:           filVested,
		FilMined:            filMined,
		FilBurnt:            filBurnt,
		FilLocked:           filLocked,
		FilCirculating:      ret,
		FilReserveDisbursed: filReserveDisbursed,
	}, nil
}

func (sm *StateManager) GetCirculatingSupply(ctx context.Context, height abi.ChainEpoch, st *state.StateTree) (abi.TokenAmount, error) {
	circ := big.Zero()
	unCirc := big.Zero()
	err := st.ForEach(func(a address.Address, actor *types.Actor) error {
		switch {
		case actor.Balance.IsZero():
			// Do nothing for zero-balance actors
			break
		case a == _init.Address ||
			a == reward.Address ||
			a == verifreg.Address ||
			// The power actor itself should never receive funds
			a == power.Address ||
			a == builtin.SystemActorAddr ||
			a == builtin.CronActorAddr ||
			a == builtin.BurntFundsActorAddr ||
			a == builtin.SaftAddress ||
			a == builtin.ReserveAddress:

			unCirc = big.Add(unCirc, actor.Balance)

		case a == market.Address:
			mst, err := market.Load(sm.cs.ActorStore(ctx), actor)
			if err != nil {
				return err
			}

			lb, err := mst.TotalLocked()
			if err != nil {
				return err
			}

			circ = big.Add(circ, big.Sub(actor.Balance, lb))
			unCirc = big.Add(unCirc, lb)

		case builtin.IsAccountActor(actor.Code) || builtin.IsPaymentChannelActor(actor.Code):
			circ = big.Add(circ, actor.Balance)

		case builtin.IsStorageMinerActor(actor.Code):
			mst, err := miner.Load(sm.cs.ActorStore(ctx), actor)
			if err != nil {
				return err
			}

			ab, err := mst.AvailableBalance(actor.Balance)

			if err == nil {
				circ = big.Add(circ, ab)
				unCirc = big.Add(unCirc, big.Sub(actor.Balance, ab))
			} else {
				// Assume any error is because the miner state is "broken" (lower actor balance than locked funds)
				// In this case, the actor's entire balance is considered "uncirculating"
				unCirc = big.Add(unCirc, actor.Balance)
			}

		case builtin.IsMultisigActor(actor.Code):
			mst, err := multisig.Load(sm.cs.ActorStore(ctx), actor)
			if err != nil {
				return err
			}

			lb, err := mst.LockedBalance(height)
			if err != nil {
				return err
			}

			ab := big.Sub(actor.Balance, lb)
			circ = big.Add(circ, big.Max(ab, big.Zero()))
			unCirc = big.Add(unCirc, big.Min(actor.Balance, lb))
		default:
			return xerrors.Errorf("unexpected actor: %s", a)
		}

		return nil
	})

	if err != nil {
		return types.EmptyInt, err
	}

	total := big.Add(circ, unCirc)
	if !total.Equals(types.TotalFilecoinInt) {
		return types.EmptyInt, xerrors.Errorf("total filecoin didn't add to expected amount: %s != %s", total, types.TotalFilecoinInt)
	}

	return circ, nil
}

func (sm *StateManager) GetNtwkVersion(ctx context.Context, height abi.ChainEpoch) network.Version {
	// The epochs here are the _last_ epoch for every version, or -1 if the
	// version is disabled.
	for _, spec := range sm.networkVersions {
		if height <= spec.atOrBelow {
			return spec.networkVersion
		}
	}
	return sm.latestVersion
}

func (sm *StateManager) GetPaychState(ctx context.Context, addr address.Address, ts *types.TipSet) (*types.Actor, paych.State, error) {
	st, err := sm.ParentState(ts)
	if err != nil {
		return nil, nil, err
	}

	act, err := st.GetActor(addr)
	if err != nil {
		return nil, nil, err
	}

	actState, err := paych.Load(sm.cs.ActorStore(ctx), act)
	if err != nil {
		return nil, nil, err
	}
	return act, actState, nil
}

func (sm *StateManager) GetMarketState(ctx context.Context, ts *types.TipSet) (market.State, error) {
	st, err := sm.ParentState(ts)
	if err != nil {
		return nil, err
	}

	act, err := st.GetActor(market.Address)
	if err != nil {
		return nil, err
	}

	actState, err := market.Load(sm.cs.ActorStore(ctx), act)
	if err != nil {
		return nil, err
	}
	return actState, nil
}

var _ StateManagerAPI = (*StateManager)(nil)