package full

import (
	"context"
	"sync"

	"github.com/ipfs/go-cid"
	"go.uber.org/fx"
	"golang.org/x/xerrors"

	"github.com/filecoin-project/go-address"
	"github.com/filecoin-project/lotus/api"
	"github.com/filecoin-project/lotus/chain/messagepool"
	"github.com/filecoin-project/lotus/chain/store"
	"github.com/filecoin-project/lotus/chain/types"
)

type MpoolAPI struct {
	fx.In

	WalletAPI
	GasAPI

	Chain *store.ChainStore

	Mpool *messagepool.MessagePool

	PushLocks struct {
		m map[address.Address]chan struct{}
		sync.Mutex
	} `name:"verymuchunique" optional:"true"`
}

func (a *MpoolAPI) MpoolGetConfig(context.Context) (*types.MpoolConfig, error) {
	return a.Mpool.GetConfig(), nil
}

func (a *MpoolAPI) MpoolSetConfig(ctx context.Context, cfg *types.MpoolConfig) error {
	a.Mpool.SetConfig(cfg)
	return nil
}

func (a *MpoolAPI) MpoolSelect(ctx context.Context, tsk types.TipSetKey) ([]*types.SignedMessage, error) {
	ts, err := a.Chain.GetTipSetFromKey(tsk)
	if err != nil {
		return nil, xerrors.Errorf("loading tipset %s: %w", tsk, err)
	}

	return a.Mpool.SelectMessages(ts)
}

func (a *MpoolAPI) MpoolPending(ctx context.Context, tsk types.TipSetKey) ([]*types.SignedMessage, error) {
	ts, err := a.Chain.GetTipSetFromKey(tsk)
	if err != nil {
		return nil, xerrors.Errorf("loading tipset %s: %w", tsk, err)
	}
	pending, mpts := a.Mpool.Pending()

	haveCids := map[cid.Cid]struct{}{}
	for _, m := range pending {
		haveCids[m.Cid()] = struct{}{}
	}

	if ts == nil || mpts.Height() > ts.Height() {
		return pending, nil
	}

	for {
		if mpts.Height() == ts.Height() {
			if mpts.Equals(ts) {
				return pending, nil
			}
			// different blocks in tipsets

			have, err := a.Mpool.MessagesForBlocks(ts.Blocks())
			if err != nil {
				return nil, xerrors.Errorf("getting messages for base ts: %w", err)
			}

			for _, m := range have {
				haveCids[m.Cid()] = struct{}{}
			}
		}

		msgs, err := a.Mpool.MessagesForBlocks(ts.Blocks())
		if err != nil {
			return nil, xerrors.Errorf(": %w", err)
		}

		for _, m := range msgs {
			if _, ok := haveCids[m.Cid()]; ok {
				continue
			}

			haveCids[m.Cid()] = struct{}{}
			pending = append(pending, m)
		}

		if mpts.Height() >= ts.Height() {
			return pending, nil
		}

		ts, err = a.Chain.LoadTipSet(ts.Parents())
		if err != nil {
			return nil, xerrors.Errorf("loading parent tipset: %w", err)
		}
	}
}

func (a *MpoolAPI) MpoolPush(ctx context.Context, smsg *types.SignedMessage) (cid.Cid, error) {
	return a.Mpool.Push(smsg)
}

func (a *MpoolAPI) MpoolPushMessage(ctx context.Context, msg *types.Message) (*types.SignedMessage, error) {
	{
		fromA, err := a.Stmgr.ResolveToKeyAddress(ctx, msg.From, nil)
		if err != nil {
			return nil, xerrors.Errorf("getting key address: %w", err)
		}

		a.PushLocks.Lock()
		if a.PushLocks.m == nil {
			a.PushLocks.m = make(map[address.Address]chan struct{})
		}
		lk, ok := a.PushLocks.m[fromA]
		if !ok {
			lk = make(chan struct{}, 1)
			a.PushLocks.m[msg.From] = lk
		}
		a.PushLocks.Unlock()

		select {
		case lk <- struct{}{}:
		case <-ctx.Done():
			return nil, ctx.Err()
		}

		defer func() {
			<-lk
		}()
	}

	if msg.Nonce != 0 {
		return nil, xerrors.Errorf("MpoolPushMessage expects message nonce to be 0, was %d", msg.Nonce)
	}
	if msg.GasLimit == 0 {
		gasLimit, err := a.GasEstimateGasLimit(ctx, msg, types.TipSetKey{})
		if err != nil {
			return nil, xerrors.Errorf("estimating gas used: %w", err)
		}
		msg.GasLimit = int64(float64(gasLimit) * a.Mpool.GetConfig().GasLimitOverestimation)
	}

	if msg.GasPremium == types.EmptyInt || types.BigCmp(msg.GasPremium, types.NewInt(0)) == 0 {
		gasPremium, err := a.GasEsitmateGasPremium(ctx, 2, msg.From, msg.GasLimit, types.TipSetKey{})
		if err != nil {
			return nil, xerrors.Errorf("estimating gas price: %w", err)
		}
		msg.GasPremium = gasPremium
	}

	if msg.GasFeeCap == types.EmptyInt || types.BigCmp(msg.GasFeeCap, types.NewInt(0)) == 0 {
		feeCap, err := a.GasEstimateFeeCap(ctx, msg, 10, types.EmptyTSK)
		if err != nil {
			return nil, xerrors.Errorf("estimating fee cap: %w", err)
		}
		msg.GasFeeCap = feeCap
	}

	return a.Mpool.PushWithNonce(ctx, msg.From, func(from address.Address, nonce uint64) (*types.SignedMessage, error) {
		msg.Nonce = nonce
		if msg.From.Protocol() == address.ID {
			log.Warnf("Push from ID address (%s), adjusting to %s", msg.From, from)
			msg.From = from
		}

		b, err := a.WalletBalance(ctx, msg.From)
		if err != nil {
			return nil, xerrors.Errorf("mpool push: getting origin balance: %w", err)
		}

		if b.LessThan(msg.Value) {
			return nil, xerrors.Errorf("mpool push: not enough funds: %s < %s", b, msg.Value)
		}

		return a.WalletSignMessage(ctx, from, msg)
	})
}

func (a *MpoolAPI) MpoolGetNonce(ctx context.Context, addr address.Address) (uint64, error) {
	return a.Mpool.GetNonce(addr)
}

func (a *MpoolAPI) MpoolSub(ctx context.Context) (<-chan api.MpoolUpdate, error) {
	return a.Mpool.Updates(ctx)
}