package full

import (
	"context"
	"fmt"
	"io"
	"strconv"
	"strings"

	"github.com/filecoin-project/go-amt-ipld"
	"github.com/ipfs/go-blockservice"
	"github.com/ipfs/go-cid"
	"github.com/ipfs/go-hamt-ipld"
	blockstore "github.com/ipfs/go-ipfs-blockstore"
	offline "github.com/ipfs/go-ipfs-exchange-offline"
	cbor "github.com/ipfs/go-ipld-cbor"
	ipld "github.com/ipfs/go-ipld-format"
	"github.com/ipfs/go-merkledag"
	"github.com/ipfs/go-path"
	"github.com/ipfs/go-path/resolver"
	mh "github.com/multiformats/go-multihash"
	"github.com/prometheus/common/log"
	"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/store"
	"github.com/filecoin-project/lotus/chain/types"
)

type ChainAPI struct {
	fx.In

	WalletAPI

	Chain *store.ChainStore
}

func (a *ChainAPI) ChainNotify(ctx context.Context) (<-chan []*store.HeadChange, error) {
	return a.Chain.SubHeadChanges(ctx), nil
}

func (a *ChainAPI) ChainHead(context.Context) (*types.TipSet, error) {
	return a.Chain.GetHeaviestTipSet(), nil
}

func (a *ChainAPI) ChainGetRandomness(ctx context.Context, pts types.TipSetKey, round int64) ([]byte, error) {
	return a.Chain.GetRandomness(ctx, pts.Cids(), round)
}

func (a *ChainAPI) ChainGetBlock(ctx context.Context, msg cid.Cid) (*types.BlockHeader, error) {
	return a.Chain.GetBlock(msg)
}

func (a *ChainAPI) ChainGetTipSet(ctx context.Context, key types.TipSetKey) (*types.TipSet, error) {
	return a.Chain.LoadTipSet(key)
}

func (a *ChainAPI) ChainGetBlockMessages(ctx context.Context, msg cid.Cid) (*api.BlockMessages, error) {
	b, err := a.Chain.GetBlock(msg)
	if err != nil {
		return nil, err
	}

	bmsgs, smsgs, err := a.Chain.MessagesForBlock(b)
	if err != nil {
		return nil, err
	}

	cids := make([]cid.Cid, len(bmsgs)+len(smsgs))

	for i, m := range bmsgs {
		cids[i] = m.Cid()
	}

	for i, m := range smsgs {
		cids[i+len(bmsgs)] = m.Cid()
	}

	return &api.BlockMessages{
		BlsMessages:   bmsgs,
		SecpkMessages: smsgs,
		Cids:          cids,
	}, nil
}

func (a *ChainAPI) ChainGetPath(ctx context.Context, from types.TipSetKey, to types.TipSetKey) ([]*store.HeadChange, error) {
	return a.Chain.GetPath(ctx, from, to)
}

func (a *ChainAPI) ChainGetParentMessages(ctx context.Context, bcid cid.Cid) ([]api.Message, error) {
	b, err := a.Chain.GetBlock(bcid)
	if err != nil {
		return nil, err
	}

	// genesis block has no parent messages...
	if b.Height == 0 {
		return nil, nil
	}

	// TODO: need to get the number of messages better than this
	pts, err := a.Chain.LoadTipSet(types.NewTipSetKey(b.Parents...))
	if err != nil {
		return nil, err
	}

	cm, err := a.Chain.MessagesForTipset(pts)
	if err != nil {
		return nil, err
	}

	var out []api.Message
	for _, m := range cm {
		out = append(out, api.Message{
			Cid:     m.Cid(),
			Message: m.VMMessage(),
		})
	}

	return out, nil
}

func (a *ChainAPI) ChainGetParentReceipts(ctx context.Context, bcid cid.Cid) ([]*types.MessageReceipt, error) {
	b, err := a.Chain.GetBlock(bcid)
	if err != nil {
		return nil, err
	}

	if b.Height == 0 {
		return nil, nil
	}

	// TODO: need to get the number of messages better than this
	pts, err := a.Chain.LoadTipSet(types.NewTipSetKey(b.Parents...))
	if err != nil {
		return nil, err
	}

	cm, err := a.Chain.MessagesForTipset(pts)
	if err != nil {
		return nil, err
	}

	var out []*types.MessageReceipt
	for i := 0; i < len(cm); i++ {
		r, err := a.Chain.GetParentReceipt(b, i)
		if err != nil {
			return nil, err
		}

		out = append(out, r)
	}

	return out, nil
}

func (a *ChainAPI) ChainGetTipSetByHeight(ctx context.Context, h uint64, ts *types.TipSet) (*types.TipSet, error) {
	return a.Chain.GetTipsetByHeight(ctx, h, ts)
}

func (a *ChainAPI) ChainReadObj(ctx context.Context, obj cid.Cid) ([]byte, error) {
	blk, err := a.Chain.Blockstore().Get(obj)
	if err != nil {
		return nil, xerrors.Errorf("blockstore get: %w", err)
	}

	return blk.RawData(), nil
}

func (a *ChainAPI) ChainHasObj(ctx context.Context, obj cid.Cid) (bool, error) {
	return a.Chain.Blockstore().Has(obj)
}

func (a *ChainAPI) ChainSetHead(ctx context.Context, ts *types.TipSet) error {
	return a.Chain.SetHead(ts)
}

func (a *ChainAPI) ChainGetGenesis(ctx context.Context) (*types.TipSet, error) {
	genb, err := a.Chain.GetGenesis()
	if err != nil {
		return nil, err
	}

	return types.NewTipSet([]*types.BlockHeader{genb})
}

func (a *ChainAPI) ChainTipSetWeight(ctx context.Context, ts *types.TipSet) (types.BigInt, error) {
	return a.Chain.Weight(ctx, ts)
}

func resolveOnce(bs blockstore.Blockstore) func(ctx context.Context, ds ipld.NodeGetter, nd ipld.Node, names []string) (*ipld.Link, []string, error) {
	return func(ctx context.Context, ds ipld.NodeGetter, nd ipld.Node, names []string) (*ipld.Link, []string, error) {
		if strings.HasPrefix(names[0], "@Ha:") {
			addr, err := address.NewFromString(names[0][4:])
			if err != nil {
				return nil, nil, xerrors.Errorf("parsing addr: %w", err)
			}

			names[0] = "@H:" + string(addr.Bytes())
		}

		if strings.HasPrefix(names[0], "@H:") {
			cst := hamt.CSTFromBstore(bs)

			h, err := hamt.LoadNode(ctx, cst, nd.Cid())
			if err != nil {
				return nil, nil, xerrors.Errorf("resolving hamt link: %w", err)
			}

			var m interface{}
			if err := h.Find(ctx, names[0][3:], &m); err != nil {
				return nil, nil, xerrors.Errorf("resolve hamt: %w", err)
			}
			if c, ok := m.(cid.Cid); ok {
				return &ipld.Link{
					Name: names[0][3:],
					Cid:  c,
				}, names[1:], nil
			}

			n, err := cbor.WrapObject(m, mh.SHA2_256, 32)
			if err != nil {
				return nil, nil, err
			}

			if err := bs.Put(n); err != nil {
				return nil, nil, xerrors.Errorf("put hamt val: %w", err)
			}

			if len(names) == 1 {
				return &ipld.Link{
					Name: names[0][3:],
					Cid:  n.Cid(),
				}, nil, nil
			}

			return resolveOnce(bs)(ctx, ds, n, names[1:])
		}

		if strings.HasPrefix(names[0], "@A:") {
			a, err := amt.LoadAMT(amt.WrapBlockstore(bs), nd.Cid())
			if err != nil {
				return nil, nil, xerrors.Errorf("load amt: %w", err)
			}

			idx, err := strconv.ParseUint(names[0][3:], 10, 64)
			if err != nil {
				return nil, nil, xerrors.Errorf("parsing amt index: %w", err)
			}

			var m interface{}
			if err := a.Get(idx, &m); err != nil {
				return nil, nil, xerrors.Errorf("amt get: %w", err)
			}
			fmt.Printf("AG %T %v\n", m, m)
			if c, ok := m.(cid.Cid); ok {
				return &ipld.Link{
					Name: names[0][3:],
					Cid:  c,
				}, names[1:], nil
			}

			n, err := cbor.WrapObject(m, mh.SHA2_256, 32)
			if err != nil {
				return nil, nil, err
			}

			if err := bs.Put(n); err != nil {
				return nil, nil, xerrors.Errorf("put amt val: %w", err)
			}

			if len(names) == 1 {
				return &ipld.Link{
					Name: names[0][3:],
					Size: 0,
					Cid:  n.Cid(),
				}, nil, nil
			}

			return resolveOnce(bs)(ctx, ds, n, names[1:])
		}

		return nd.ResolveLink(names)
	}
}

func (a *ChainAPI) ChainGetNode(ctx context.Context, p string) (interface{}, error) {
	ip, err := path.ParsePath(p)
	if err != nil {
		return nil, xerrors.Errorf("parsing path: %w", err)
	}

	bs := a.Chain.Blockstore()
	bsvc := blockservice.New(bs, offline.Exchange(bs))

	dag := merkledag.NewDAGService(bsvc)

	r := &resolver.Resolver{
		DAG:         dag,
		ResolveOnce: resolveOnce(bs),
	}

	node, err := r.ResolvePath(ctx, ip)
	if err != nil {
		return nil, err
	}

	return node, nil
}

func (a *ChainAPI) ChainGetMessage(ctx context.Context, mc cid.Cid) (*types.Message, error) {
	cm, err := a.Chain.GetCMessage(mc)
	if err != nil {
		return nil, err
	}

	return cm.VMMessage(), nil
}

func (a *ChainAPI) ChainExport(ctx context.Context, ts *types.TipSet) (<-chan []byte, error) {
	r, w := io.Pipe()
	out := make(chan []byte)
	go func() {
		defer w.Close()
		if err := a.Chain.Export(ctx, ts, w); err != nil {
			log.Errorf("chain export call failed: %s", err)
			return
		}
	}()

	go func() {
		defer close(out)
		for {
			buf := make([]byte, 4096)
			n, err := r.Read(buf)
			if err != nil {
				log.Errorf("chain export pipe read failed: %s", err)
				return
			}
			select {
			case out <- buf[:n]:
			case <-ctx.Done():
				log.Warnf("export writer failed: %s", ctx.Err())
			}
		}
	}()

	return out, nil
}