package util

import (
	"encoding/base64"
	"encoding/hex"
	"fmt"
	"os"

	"github.com/nspcc-dev/neo-go/cli/flags"
	"github.com/nspcc-dev/neo-go/cli/options"
	"github.com/nspcc-dev/neo-go/cli/txctx"
	vmcli "github.com/nspcc-dev/neo-go/cli/vm"
	"github.com/nspcc-dev/neo-go/pkg/vm"
	"github.com/urfave/cli"
)

// NewCommands returns util commands for neo-go CLI.
func NewCommands() []cli.Command {
	txDumpFlags := append([]cli.Flag{}, options.RPC...)
	txCancelFlags := append([]cli.Flag{
		flags.AddressFlag{
			Name:  "address, a",
			Usage: "address to use as conflicting transaction signee (and gas source)",
		},
		txctx.GasFlag,
	}, options.RPC...)
	txCancelFlags = append(txCancelFlags, options.Wallet...)
	return []cli.Command{
		{
			Name:  "util",
			Usage: "Various helper commands",
			Subcommands: []cli.Command{
				{
					Name:  "convert",
					Usage: "Convert provided argument into other possible formats",
					UsageText: `convert <arg>

<arg> is an argument which is tried to be interpreted as an item of different types
        and converted to other formats. Strings are escaped and output in quotes.`,
					Action: handleParse,
				},
				{
					Name:      "sendtx",
					Usage:     "Send complete transaction stored in a context file",
					UsageText: "sendtx [-r <endpoint>] <file.in>",
					Description: `Sends the transaction from the given context file to the given RPC node if it's
   completely signed and ready. This command expects a ContractParametersContext
   JSON file for input, it can't handle binary (or hex- or base64-encoded)
   transactions.
`,
					Action: sendTx,
					Flags:  txDumpFlags,
				},
				{
					Name:      "canceltx",
					Usage:     "Cancel transaction by sending conflicting transaction",
					UsageText: "canceltx <txid> -r <endpoint> --wallet <wallet> [--account <account>] [--wallet-config <path>] [--gas <gas>]",
					Description: `Aims to prevent a transaction from being added to the blockchain by dispatching a more 
prioritized conflicting transaction to the specified RPC node. The input for this command should 
be the transaction hash. If another account is not specified, the conflicting transaction is 
automatically generated and signed by the default account in the wallet. If the target transaction 
is in the memory pool of the provided RPC node, the NetworkFee value of the conflicting transaction 
is set to the target transaction's NetworkFee value plus one (if it's sufficient for the 
conflicting transaction itself). If the target transaction is not in the memory pool, standard 
NetworkFee calculations are performed based on the calculatenetworkfee RPC request. If the --gas 
flag is included, the specified value is added to the resulting conflicting transaction network fee 
in both scenarios.
`,
					Action: cancelTx,
					Flags:  txCancelFlags,
				},
				{
					Name:      "txdump",
					Usage:     "Dump transaction stored in file",
					UsageText: "txdump [-r <endpoint>] <file.in>",
					Action:    txDump,
					Flags:     txDumpFlags,
				},
				{
					Name:      "ops",
					Usage:     "Pretty-print VM opcodes of the given base64- or hex- encoded script (base64 is checked first). If the input file is specified, then the script is taken from the file.",
					UsageText: "ops <base64/hex-encoded script> [-i path-to-file] [--hex]",
					Action:    handleOps,
					Flags: []cli.Flag{
						cli.StringFlag{
							Name:  "in, i",
							Usage: "input file containing base64- or hex- encoded script representation",
						},
						cli.BoolFlag{
							Name:  "hex",
							Usage: "use hex encoding and do not check base64",
						},
					},
				},
			},
		},
	}
}

func handleParse(ctx *cli.Context) error {
	res, err := vmcli.Parse(ctx.Args())
	if err != nil {
		return cli.NewExitError(err, 1)
	}
	fmt.Fprint(ctx.App.Writer, res)
	return nil
}

func handleOps(ctx *cli.Context) error {
	var (
		s   string
		err error
		b   []byte
	)
	in := ctx.String("in")
	if len(in) != 0 {
		b, err := os.ReadFile(in)
		if err != nil {
			return cli.NewExitError(fmt.Errorf("failed to read file: %w", err), 1)
		}
		s = string(b)
	} else {
		if !ctx.Args().Present() {
			return cli.NewExitError("missing script", 1)
		}
		s = ctx.Args()[0]
	}
	b, err = base64.StdEncoding.DecodeString(s)
	if err != nil || ctx.Bool("hex") {
		b, err = hex.DecodeString(s)
	}
	if err != nil {
		return cli.NewExitError("unknown encoding: base64 or hex are supported", 1)
	}
	v := vm.New()
	v.LoadScript(b)
	v.PrintOps(ctx.App.Writer)
	return nil
}