package main

import (
	"fmt"

	"github.com/spf13/cobra"
	"github.com/spf13/viper"

	"github.com/cosmos/cosmos-sdk/client/flags"
	"github.com/cosmos/cosmos-sdk/client/keys"
	sdk "github.com/cosmos/cosmos-sdk/types"

	"github.com/kava-labs/kava/app"
)

/*
NOTE TO FUTURE IMPLEMENTERS
This monkey patches the sdk `keys` command, therefore needs to be reviewed on any sdk updates.

Where a bip44 coin type is used (cosmos-sdk 18de630d):
- adding local keys
	- global variable `sdk.Config.CoinType` is used to derive the key from a mnemonic (supplied by user or generated), but only the private key is stored
- adding ledger keys
	- global variable `sdk.Config.CoinType` is used to reference a key on a ledger device, bip44 path (not private key) is stored locally
- signing txs with local keys
	- the stored the priv key is used to sign, mnemonics or bip44 paths not involved
- signing txs with ledger
	- the stored bip44 path is used to instruct the ledger which key to sign with
*/

const flagLegacyHDPath = "legacy-hd-path"

// getModifiedKeysCmd returns the standard cosmos-sdk/client/keys cmd but modified to support new and old bip44 coin types supported by kava.
func getModifiedKeysCmd() *cobra.Command {
	keysCmd := keys.Commands()
	for _, c := range keysCmd.Commands() {
		if c.Name() == "add" {
			monkeyPatchCmdKeysAdd(c)
			break
		}
	}
	return keysCmd
}

// monkeyPatchCmdKeysAdd modifies the `keys add` command to use the old bip44 coin type when a flag is passed.
func monkeyPatchCmdKeysAdd(keysAddCmd *cobra.Command) {
	// add flag
	keysAddCmd.Flags().Bool(flagLegacyHDPath, false, fmt.Sprintf("Use the old bip44 coin type (%d) to derive addresses from mnemonics.", sdk.CoinType))

	// replace description
	keysAddCmd.Long = fmt.Sprintf(`Derive a new private key and encrypt to disk.
	Optionally specify a BIP39 mnemonic, a BIP39 passphrase to further secure the mnemonic,
	and BIP44 account/index numbers to derive a specific key. The key will be stored under the given name
	and encrypted with the given password.

	NOTE: This cli defaults to Kava's BIP44 coin type %d. Use the --%s flag to use the old one (%d).
	
	The flag --recover allows one to recover a key from a seed passphrase.
	If run with --dry-run, a key would be generated (or recovered) but not stored to the
	local keystore.
	Use the --pubkey flag to add arbitrary public keys to the keystore for constructing
	multisig transactions.
	
	You can add a multisig key by passing the list of key names you want the public
	key to be composed of to the --multisig flag and the minimum number of signatures
	required through --multisig-threshold. The keys are sorted by address, unless
	the flag --nosort is set.
	`, app.Bip44CoinType, flagLegacyHDPath, sdk.CoinType)

	// replace the run function with a wrapped version that sets the old coin type in the global config
	oldRun := keysAddCmd.RunE
	keysAddCmd.RunE = func(cmd *cobra.Command, args []string) error {
		preExistingCoinType := sdk.GetConfig().GetCoinType()

		if viper.GetBool(flagLegacyHDPath) {
			sdk.GetConfig().SetCoinType(sdk.CoinType) // set old coin type
			err := oldRun(cmd, args)
			sdk.GetConfig().SetCoinType(preExistingCoinType) // revert to preexisting coin type
			return err
		} else {
			if viper.GetBool(flags.FlagUseLedger) {
				return fmt.Errorf("cosmos ledger app only supports legacy bip44 coin type, must use --%s flag when adding ledger key", flagLegacyHDPath)
			}
			return oldRun(cmd, args)
		}
	}
}