package cli

import (
	"bytes"
	"context"
	"encoding/binary"
	"encoding/hex"
	"fmt"
	"os"
	"sort"
	"strconv"
	"text/tabwriter"

	"github.com/filecoin-project/go-address"
	init_ "github.com/filecoin-project/specs-actors/actors/builtin/init"
	samsig "github.com/filecoin-project/specs-actors/actors/builtin/multisig"
	cid "github.com/ipfs/go-cid"
	"github.com/ipfs/go-hamt-ipld"
	cbor "github.com/ipfs/go-ipld-cbor"
	"github.com/urfave/cli/v2"
	cbg "github.com/whyrusleeping/cbor-gen"
	"golang.org/x/xerrors"

	"github.com/filecoin-project/lotus/api"
	"github.com/filecoin-project/lotus/api/apibstore"
	"github.com/filecoin-project/lotus/build"
	types "github.com/filecoin-project/lotus/chain/types"
)

var multisigCmd = &cli.Command{
	Name:  "msig",
	Usage: "Interact with a multisig wallet",
	Flags: []cli.Flag{
		&cli.StringFlag{
			Name:  "source",
			Usage: "specify the account to send propose from",
		},
	},
	Subcommands: []*cli.Command{
		msigCreateCmd,
		msigInspectCmd,
		msigProposeCmd,
		msigApproveCmd,
	},
}

var msigCreateCmd = &cli.Command{
	Name:      "create",
	Usage:     "Create a new multisig wallet",
	ArgsUsage: "[address1 address2 ...]",
	Flags: []cli.Flag{
		&cli.Int64Flag{
			Name: "required",
		},
		&cli.StringFlag{
			Name:  "value",
			Usage: "initial funds to give to multisig",
			Value: "0",
		},
		&cli.StringFlag{
			Name:  "from",
			Usage: "account to send the create message from",
		},
	},
	Action: func(cctx *cli.Context) error {
		api, closer, err := GetFullNodeAPI(cctx)
		if err != nil {
			return err
		}
		defer closer()
		ctx := ReqContext(cctx)

		if cctx.Args().Len() < 1 {
			return fmt.Errorf("multisigs must have at least one signer")
		}

		var addrs []address.Address
		for _, a := range cctx.Args().Slice() {
			addr, err := address.NewFromString(a)
			if err != nil {
				return err
			}
			addrs = append(addrs, addr)
		}

		// get the address we're going to use to create the multisig (can be one of the above, as long as they have funds)
		var sendAddr address.Address
		if send := cctx.String("from"); send == "" {
			defaddr, err := api.WalletDefaultAddress(ctx)
			if err != nil {
				return err
			}

			sendAddr = defaddr
		} else {
			addr, err := address.NewFromString(send)
			if err != nil {
				return err
			}

			sendAddr = addr
		}

		val := cctx.String("value")
		filval, err := types.ParseFIL(val)
		if err != nil {
			return err
		}

		intVal := types.BigInt(filval)

		required := cctx.Int64("required")
		if required == 0 {
			required = int64(len(addrs))
		}

		gp := types.NewInt(1)

		msgCid, err := api.MsigCreate(ctx, required, addrs, intVal, sendAddr, gp)
		if err != nil {
			return err
		}

		// wait for it to get mined into a block
		wait, err := api.StateWaitMsg(ctx, msgCid, build.MessageConfidence)
		if err != nil {
			return err
		}

		// check it executed successfully
		if wait.Receipt.ExitCode != 0 {
			fmt.Println("actor creation failed!")
			return err
		}

		// get address of newly created miner

		var execreturn init_.ExecReturn
		if err := execreturn.UnmarshalCBOR(bytes.NewReader(wait.Receipt.Return)); err != nil {
			return err
		}
		fmt.Println("Created new multisig: ", execreturn.IDAddress, execreturn.RobustAddress)

		// TODO: maybe register this somewhere
		return nil
	},
}

var msigInspectCmd = &cli.Command{
	Name:      "inspect",
	Usage:     "Inspect a multisig wallet",
	ArgsUsage: "[address]",
	Flags:     []cli.Flag{},
	Action: func(cctx *cli.Context) error {
		api, closer, err := GetFullNodeAPI(cctx)
		if err != nil {
			return err
		}
		defer closer()
		ctx := ReqContext(cctx)

		if !cctx.Args().Present() {
			return fmt.Errorf("must specify address of multisig to inspect")
		}

		maddr, err := address.NewFromString(cctx.Args().First())
		if err != nil {
			return err
		}

		act, err := api.StateGetActor(ctx, maddr, types.EmptyTSK)
		if err != nil {
			return err
		}

		obj, err := api.ChainReadObj(ctx, act.Head)
		if err != nil {
			return err
		}

		var mstate samsig.State
		if err := mstate.UnmarshalCBOR(bytes.NewReader(obj)); err != nil {
			return err
		}

		fmt.Printf("Balance: %sfil\n", types.FIL(act.Balance))
		fmt.Printf("Threshold: %d / %d\n", mstate.NumApprovalsThreshold, len(mstate.Signers))
		fmt.Println("Signers:")
		for _, s := range mstate.Signers {
			fmt.Printf("\t%s\n", s)
		}

		pending, err := GetMultisigPending(ctx, api, mstate.PendingTxns)
		if err != nil {
			return fmt.Errorf("reading pending transactions: %w", err)
		}

		fmt.Println("Transactions: ", len(pending))
		if len(pending) > 0 {
			var txids []int64
			for txid := range pending {
				txids = append(txids, txid)
			}
			sort.Slice(txids, func(i, j int) bool {
				return txids[i] < txids[j]
			})

			w := tabwriter.NewWriter(os.Stdout, 8, 4, 0, ' ', 0)
			fmt.Fprintf(w, "ID\tState\tTo\tValue\tMethod\tParams\n")
			for _, txid := range txids {
				tx := pending[txid]
				fmt.Fprintf(w, "%d\t%s\t%s\t%s\t%d\t%x\n", txid, state(tx), tx.To, types.FIL(tx.Value), tx.Method, tx.Params)
			}
			if err := w.Flush(); err != nil {
				return xerrors.Errorf("flushing output: %+v", err)
			}

		}

		return nil
	},
}

func GetMultisigPending(ctx context.Context, lapi api.FullNode, hroot cid.Cid) (map[int64]*samsig.Transaction, error) {
	bs := apibstore.NewAPIBlockstore(lapi)
	cst := cbor.NewCborStore(bs)

	nd, err := hamt.LoadNode(ctx, cst, hroot, hamt.UseTreeBitWidth(5))
	if err != nil {
		return nil, err
	}

	txs := make(map[int64]*samsig.Transaction)
	err = nd.ForEach(ctx, func(k string, val interface{}) error {
		d := val.(*cbg.Deferred)
		var tx samsig.Transaction
		if err := tx.UnmarshalCBOR(bytes.NewReader(d.Raw)); err != nil {
			return err
		}

		txid, _ := binary.Varint([]byte(k))

		txs[txid] = &tx
		return nil
	})
	if err != nil {
		return nil, xerrors.Errorf("failed to iterate transactions hamt: %w", err)
	}

	return txs, nil
}

func state(tx *samsig.Transaction) string {
	/* // TODO(why): I strongly disagree with not having these... but i need to move forward
	if tx.Complete {
		return "done"
	}
	if tx.Canceled {
		return "canceled"
	}
	*/
	return "pending"
}

var msigProposeCmd = &cli.Command{
	Name:      "propose",
	Usage:     "Propose a multisig transaction",
	ArgsUsage: "[multisigAddress destinationAddress value <methodId methodParams> (optional)]",
	Flags: []cli.Flag{
		&cli.StringFlag{
			Name:  "source",
			Usage: "account to send the propose message from",
		},
	},
	Action: func(cctx *cli.Context) error {
		api, closer, err := GetFullNodeAPI(cctx)
		if err != nil {
			return err
		}
		defer closer()
		ctx := ReqContext(cctx)

		if cctx.Args().Len() < 3 {
			return fmt.Errorf("must pass multisig address, destination, and value")
		}

		if cctx.Args().Len() > 3 && cctx.Args().Len() != 5 {
			return fmt.Errorf("usage: msig propose <msig addr> <desination> <value> [ <method> <params> ]")
		}

		msig, err := address.NewFromString(cctx.Args().Get(0))
		if err != nil {
			return err
		}

		dest, err := address.NewFromString(cctx.Args().Get(1))
		if err != nil {
			return err
		}

		value, err := types.ParseFIL(cctx.Args().Get(2))
		if err != nil {
			return err
		}

		var method uint64
		var params []byte
		if cctx.Args().Len() == 5 {
			m, err := strconv.ParseUint(cctx.Args().Get(3), 10, 64)
			if err != nil {
				return err
			}
			method = m

			p, err := hex.DecodeString(cctx.Args().Get(4))
			if err != nil {
				return err
			}
			params = p
		}

		var from address.Address
		if cctx.IsSet("source") {
			f, err := address.NewFromString(cctx.String("source"))
			if err != nil {
				return err
			}
			from = f
		} else {
			defaddr, err := api.WalletDefaultAddress(ctx)
			if err != nil {
				return err
			}
			from = defaddr
		}

		msgCid, err := api.MsigPropose(ctx, msig, dest, types.BigInt(value), from, method, params)
		if err != nil {
			return err
		}

		fmt.Println("send proposal in message: ", msgCid)

		wait, err := api.StateWaitMsg(ctx, msgCid, build.MessageConfidence)
		if err != nil {
			return err
		}

		if wait.Receipt.ExitCode != 0 {
			return fmt.Errorf("proposal returned exit %d", wait.Receipt.ExitCode)
		}

		_, v, err := cbg.CborReadHeader(bytes.NewReader(wait.Receipt.Return))
		if err != nil {
			return err
		}

		fmt.Printf("Transaction ID: %d\n", v)

		return nil
	},
}

var msigApproveCmd = &cli.Command{
	Name:      "approve",
	Usage:     "Approve a multisig message",
	ArgsUsage: "[multisigAddress messageId proposerAddress destination value <methodId methodParams> (optional)]",
	Flags: []cli.Flag{
		&cli.StringFlag{
			Name:  "source",
			Usage: "account to send the approve message from",
		},
	},
	Action: func(cctx *cli.Context) error {
		api, closer, err := GetFullNodeAPI(cctx)
		if err != nil {
			return err
		}
		defer closer()
		ctx := ReqContext(cctx)

		if cctx.Args().Len() < 5 {
			return fmt.Errorf("must pass multisig address, message ID, proposer address, destination, and value")
		}

		if cctx.Args().Len() > 5 && cctx.Args().Len() != 7 {
			return fmt.Errorf("usage: msig approve <msig addr> <message ID> <proposer address> <desination> <value> [ <method> <params> ]")
		}

		msig, err := address.NewFromString(cctx.Args().Get(0))
		if err != nil {
			return err
		}

		txid, err := strconv.ParseUint(cctx.Args().Get(1), 10, 64)
		if err != nil {
			return err
		}

		proposer, err := address.NewFromString(cctx.Args().Get(2))
		if err != nil {
			return err
		}

		if proposer.Protocol() != address.ID {
			proposer, err = api.StateLookupID(ctx, proposer, types.EmptyTSK)
			if err != nil {
				return err
			}
		}

		dest, err := address.NewFromString(cctx.Args().Get(3))
		if err != nil {
			return err
		}

		value, err := types.ParseFIL(cctx.Args().Get(4))
		if err != nil {
			return err
		}

		var method uint64
		var params []byte
		if cctx.Args().Len() == 7 {
			m, err := strconv.ParseUint(cctx.Args().Get(5), 10, 64)
			if err != nil {
				return err
			}
			method = m

			p, err := hex.DecodeString(cctx.Args().Get(6))
			if err != nil {
				return err
			}
			params = p
		}

		var from address.Address
		if cctx.IsSet("source") {
			f, err := address.NewFromString(cctx.String("source"))
			if err != nil {
				return err
			}
			from = f
		} else {
			defaddr, err := api.WalletDefaultAddress(ctx)
			if err != nil {
				return err
			}
			from = defaddr
		}

		msgCid, err := api.MsigApprove(ctx, msig, txid, proposer, dest, types.BigInt(value), from, method, params)
		if err != nil {
			return err
		}

		fmt.Println("sent approval in message: ", msgCid)

		wait, err := api.StateWaitMsg(ctx, msgCid, build.MessageConfidence)
		if err != nil {
			return err
		}

		if wait.Receipt.ExitCode != 0 {
			return fmt.Errorf("approve returned exit %d", wait.Receipt.ExitCode)
		}

		return nil
	},
}