package api

import (
	"encoding/json"
	"net/http"
	"path/filepath"
	"strconv"
	"strings"

	"github.com/NebulousLabs/Sia/crypto"
	"github.com/NebulousLabs/Sia/modules"
	"github.com/NebulousLabs/Sia/types"

	"github.com/NebulousLabs/entropy-mnemonics"
	"github.com/julienschmidt/httprouter"
)

type (
	// WalletGET contains general information about the wallet.
	WalletGET struct {
		Encrypted  bool `json:"encrypted"`
		Unlocked   bool `json:"unlocked"`
		Rescanning bool `json:"rescanning"`

		ConfirmedSiacoinBalance     types.Currency `json:"confirmedsiacoinbalance"`
		UnconfirmedOutgoingSiacoins types.Currency `json:"unconfirmedoutgoingsiacoins"`
		UnconfirmedIncomingSiacoins types.Currency `json:"unconfirmedincomingsiacoins"`

		SiafundBalance      types.Currency `json:"siafundbalance"`
		SiacoinClaimBalance types.Currency `json:"siacoinclaimbalance"`
	}

	// WalletAddressGET contains an address returned by a GET call to
	// /wallet/address.
	WalletAddressGET struct {
		Address types.UnlockHash `json:"address"`
	}

	// WalletAddressesGET contains the list of wallet addresses returned by a
	// GET call to /wallet/addresses.
	WalletAddressesGET struct {
		Addresses []types.UnlockHash `json:"addresses"`
	}

	// WalletInitPOST contains the primary seed that gets generated during a
	// POST call to /wallet/init.
	WalletInitPOST struct {
		PrimarySeed string `json:"primaryseed"`
	}

	// WalletSiacoinsPOST contains the transaction sent in the POST call to
	// /wallet/siacoins.
	WalletSiacoinsPOST struct {
		TransactionIDs []types.TransactionID `json:"transactionids"`
	}

	// WalletSiafundsPOST contains the transaction sent in the POST call to
	// /wallet/siafunds.
	WalletSiafundsPOST struct {
		TransactionIDs []types.TransactionID `json:"transactionids"`
	}

	// WalletSeedsGET contains the seeds used by the wallet.
	WalletSeedsGET struct {
		PrimarySeed        string   `json:"primaryseed"`
		AddressesRemaining int      `json:"addressesremaining"`
		AllSeeds           []string `json:"allseeds"`
	}

	// WalletSweepPOST contains the coins and funds returned by a call to
	// /wallet/sweep.
	WalletSweepPOST struct {
		Coins types.Currency `json:"coins"`
		Funds types.Currency `json:"funds"`
	}

	// WalletTransactionGETid contains the transaction returned by a call to
	// /wallet/transaction/:id
	WalletTransactionGETid struct {
		Transaction modules.ProcessedTransaction `json:"transaction"`
	}

	// WalletTransactionsGET contains the specified set of confirmed and
	// unconfirmed transactions.
	WalletTransactionsGET struct {
		ConfirmedTransactions   []modules.ProcessedTransaction `json:"confirmedtransactions"`
		UnconfirmedTransactions []modules.ProcessedTransaction `json:"unconfirmedtransactions"`
	}

	// WalletTransactionsGETaddr contains the set of wallet transactions
	// relevant to the input address provided in the call to
	// /wallet/transaction/:addr
	WalletTransactionsGETaddr struct {
		ConfirmedTransactions   []modules.ProcessedTransaction `json:"confirmedtransactions"`
		UnconfirmedTransactions []modules.ProcessedTransaction `json:"unconfirmedtransactions"`
	}

	// WalletVerifyAddressGET contains a bool indicating if the address passed to
	// /wallet/verify/address/:addr is a valid address.
	WalletVerifyAddressGET struct {
		Valid bool
	}
)

// encryptionKeys enumerates the possible encryption keys that can be derived
// from an input string.
func encryptionKeys(seedStr string) (validKeys []crypto.TwofishKey) {
	dicts := []mnemonics.DictionaryID{"english", "german", "japanese"}
	for _, dict := range dicts {
		seed, err := modules.StringToSeed(seedStr, dict)
		if err != nil {
			continue
		}
		validKeys = append(validKeys, crypto.TwofishKey(crypto.HashObject(seed)))
	}
	validKeys = append(validKeys, crypto.TwofishKey(crypto.HashObject(seedStr)))
	return validKeys
}

// walletHander handles API calls to /wallet.
func (api *API) walletHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	siacoinBal, siafundBal, siaclaimBal := api.wallet.ConfirmedBalance()
	siacoinsOut, siacoinsIn := api.wallet.UnconfirmedBalance()
	WriteJSON(w, WalletGET{
		Encrypted:  api.wallet.Encrypted(),
		Unlocked:   api.wallet.Unlocked(),
		Rescanning: api.wallet.Rescanning(),

		ConfirmedSiacoinBalance:     siacoinBal,
		UnconfirmedOutgoingSiacoins: siacoinsOut,
		UnconfirmedIncomingSiacoins: siacoinsIn,

		SiafundBalance:      siafundBal,
		SiacoinClaimBalance: siaclaimBal,
	})
}

// wallet033xHandler handles API calls to /wallet/033x.
func (api *API) wallet033xHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	source := req.FormValue("source")
	// Check that source is an absolute paths.
	if !filepath.IsAbs(source) {
		WriteError(w, Error{"error when calling /wallet/033x: source must be an absolute path"}, http.StatusBadRequest)
		return
	}
	potentialKeys := encryptionKeys(req.FormValue("encryptionpassword"))
	for _, key := range potentialKeys {
		err := api.wallet.Load033xWallet(key, source)
		if err == nil {
			WriteSuccess(w)
			return
		}
		if err != nil && err != modules.ErrBadEncryptionKey {
			WriteError(w, Error{"error when calling /wallet/033x: " + err.Error()}, http.StatusBadRequest)
			return
		}
	}
	WriteError(w, Error{modules.ErrBadEncryptionKey.Error()}, http.StatusBadRequest)
}

// walletAddressHandler handles API calls to /wallet/address.
func (api *API) walletAddressHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	unlockConditions, err := api.wallet.NextAddress()
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/addresses: " + err.Error()}, http.StatusBadRequest)
		return
	}
	WriteJSON(w, WalletAddressGET{
		Address: unlockConditions.UnlockHash(),
	})
}

// walletAddressHandler handles API calls to /wallet/addresses.
func (api *API) walletAddressesHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	WriteJSON(w, WalletAddressesGET{
		Addresses: api.wallet.AllAddresses(),
	})
}

// walletBackupHandler handles API calls to /wallet/backup.
func (api *API) walletBackupHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	destination := req.FormValue("destination")
	// Check that the destination is absolute.
	if !filepath.IsAbs(destination) {
		WriteError(w, Error{"error when calling /wallet/backup: destination must be an absolute path"}, http.StatusBadRequest)
		return
	}
	err := api.wallet.CreateBackup(destination)
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/backup: " + err.Error()}, http.StatusBadRequest)
		return
	}
	WriteSuccess(w)
}

// walletInitHandler handles API calls to /wallet/init.
func (api *API) walletInitHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	var encryptionKey crypto.TwofishKey
	if req.FormValue("encryptionpassword") != "" {
		encryptionKey = crypto.TwofishKey(crypto.HashObject(req.FormValue("encryptionpassword")))
	}

	if req.FormValue("force") == "true" {
		err := api.wallet.Reset()
		if err != nil {
			WriteError(w, Error{"error when calling /wallet/init: " + err.Error()}, http.StatusBadRequest)
			return
		}
	}
	seed, err := api.wallet.Encrypt(encryptionKey)
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/init: " + err.Error()}, http.StatusBadRequest)
		return
	}

	dictID := mnemonics.DictionaryID(req.FormValue("dictionary"))
	if dictID == "" {
		dictID = "english"
	}
	seedStr, err := modules.SeedToString(seed, dictID)
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/init: " + err.Error()}, http.StatusBadRequest)
		return
	}
	WriteJSON(w, WalletInitPOST{
		PrimarySeed: seedStr,
	})
}

// walletInitSeedHandler handles API calls to /wallet/init/seed.
func (api *API) walletInitSeedHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	var encryptionKey crypto.TwofishKey
	if req.FormValue("encryptionpassword") != "" {
		encryptionKey = crypto.TwofishKey(crypto.HashObject(req.FormValue("encryptionpassword")))
	}
	dictID := mnemonics.DictionaryID(req.FormValue("dictionary"))
	if dictID == "" {
		dictID = "english"
	}
	seed, err := modules.StringToSeed(req.FormValue("seed"), dictID)
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/init/seed: " + err.Error()}, http.StatusBadRequest)
		return
	}

	if req.FormValue("force") == "true" {
		err = api.wallet.Reset()
		if err != nil {
			WriteError(w, Error{"error when calling /wallet/init/seed: " + err.Error()}, http.StatusBadRequest)
			return
		}
	}

	err = api.wallet.InitFromSeed(encryptionKey, seed)
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/init/seed: " + err.Error()}, http.StatusBadRequest)
		return
	}
	WriteSuccess(w)
}

// walletSeedHandler handles API calls to /wallet/seed.
func (api *API) walletSeedHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	// Get the seed using the ditionary + phrase
	dictID := mnemonics.DictionaryID(req.FormValue("dictionary"))
	if dictID == "" {
		dictID = "english"
	}
	seed, err := modules.StringToSeed(req.FormValue("seed"), dictID)
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/seed: " + err.Error()}, http.StatusBadRequest)
		return
	}

	potentialKeys := encryptionKeys(req.FormValue("encryptionpassword"))
	for _, key := range potentialKeys {
		err := api.wallet.LoadSeed(key, seed)
		if err == nil {
			WriteSuccess(w)
			return
		}
		if err != nil && err != modules.ErrBadEncryptionKey {
			WriteError(w, Error{"error when calling /wallet/seed: " + err.Error()}, http.StatusBadRequest)
			return
		}
	}
	WriteError(w, Error{"error when calling /wallet/seed: " + modules.ErrBadEncryptionKey.Error()}, http.StatusBadRequest)
}

// walletSiagkeyHandler handles API calls to /wallet/siagkey.
func (api *API) walletSiagkeyHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	// Fetch the list of keyfiles from the post body.
	keyfiles := strings.Split(req.FormValue("keyfiles"), ",")
	potentialKeys := encryptionKeys(req.FormValue("encryptionpassword"))

	for _, keypath := range keyfiles {
		// Check that all key paths are absolute paths.
		if !filepath.IsAbs(keypath) {
			WriteError(w, Error{"error when calling /wallet/siagkey: keyfiles contains a non-absolute path"}, http.StatusBadRequest)
			return
		}
	}

	for _, key := range potentialKeys {
		err := api.wallet.LoadSiagKeys(key, keyfiles)
		if err == nil {
			WriteSuccess(w)
			return
		}
		if err != nil && err != modules.ErrBadEncryptionKey {
			WriteError(w, Error{"error when calling /wallet/siagkey: " + err.Error()}, http.StatusBadRequest)
			return
		}
	}
	WriteError(w, Error{"error when calling /wallet/siagkey: " + modules.ErrBadEncryptionKey.Error()}, http.StatusBadRequest)
}

// walletLockHanlder handles API calls to /wallet/lock.
func (api *API) walletLockHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	err := api.wallet.Lock()
	if err != nil {
		WriteError(w, Error{err.Error()}, http.StatusBadRequest)
		return
	}
	WriteSuccess(w)
}

// walletSeedsHandler handles API calls to /wallet/seeds.
func (api *API) walletSeedsHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	dictionary := mnemonics.DictionaryID(req.FormValue("dictionary"))
	if dictionary == "" {
		dictionary = mnemonics.English
	}

	// Get the primary seed information.
	primarySeed, addrsRemaining, err := api.wallet.PrimarySeed()
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/seeds: " + err.Error()}, http.StatusBadRequest)
		return
	}
	primarySeedStr, err := modules.SeedToString(primarySeed, dictionary)
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/seeds: " + err.Error()}, http.StatusBadRequest)
		return
	}

	// Get the list of seeds known to the wallet.
	allSeeds, err := api.wallet.AllSeeds()
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/seeds: " + err.Error()}, http.StatusBadRequest)
		return
	}
	var allSeedsStrs []string
	for _, seed := range allSeeds {
		str, err := modules.SeedToString(seed, dictionary)
		if err != nil {
			WriteError(w, Error{"error when calling /wallet/seeds: " + err.Error()}, http.StatusBadRequest)
			return
		}
		allSeedsStrs = append(allSeedsStrs, str)
	}
	WriteJSON(w, WalletSeedsGET{
		PrimarySeed:        primarySeedStr,
		AddressesRemaining: int(addrsRemaining),
		AllSeeds:           allSeedsStrs,
	})
}

// walletSiacoinsHandler handles API calls to /wallet/siacoins.
func (api *API) walletSiacoinsHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	var txns []types.Transaction
	if req.FormValue("outputs") != "" {
		// multiple amounts + destinations
		if req.FormValue("amount") != "" || req.FormValue("destination") != "" {
			WriteError(w, Error{"cannot supply both 'outputs' and single amount+destination pair"}, http.StatusInternalServerError)
			return
		}

		var outputs []types.SiacoinOutput
		err := json.Unmarshal([]byte(req.FormValue("outputs")), &outputs)
		if err != nil {
			WriteError(w, Error{"could not decode outputs: " + err.Error()}, http.StatusInternalServerError)
			return
		}
		txns, err = api.wallet.SendSiacoinsMulti(outputs)
		if err != nil {
			WriteError(w, Error{"error when calling /wallet/siacoins: " + err.Error()}, http.StatusInternalServerError)
			return
		}
	} else {
		// single amount + destination
		amount, ok := scanAmount(req.FormValue("amount"))
		if !ok {
			WriteError(w, Error{"could not read amount from POST call to /wallet/siacoins"}, http.StatusBadRequest)
			return
		}
		dest, err := scanAddress(req.FormValue("destination"))
		if err != nil {
			WriteError(w, Error{"could not read address from POST call to /wallet/siacoins"}, http.StatusBadRequest)
			return
		}

		txns, err = api.wallet.SendSiacoins(amount, dest)
		if err != nil {
			WriteError(w, Error{"error when calling /wallet/siacoins: " + err.Error()}, http.StatusInternalServerError)
			return
		}

	}

	var txids []types.TransactionID
	for _, txn := range txns {
		txids = append(txids, txn.ID())
	}
	WriteJSON(w, WalletSiacoinsPOST{
		TransactionIDs: txids,
	})
}

// walletSiafundsHandler handles API calls to /wallet/siafunds.
func (api *API) walletSiafundsHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	amount, ok := scanAmount(req.FormValue("amount"))
	if !ok {
		WriteError(w, Error{"could not read 'amount' from POST call to /wallet/siafunds"}, http.StatusBadRequest)
		return
	}
	dest, err := scanAddress(req.FormValue("destination"))
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/siafunds: " + err.Error()}, http.StatusBadRequest)
		return
	}

	txns, err := api.wallet.SendSiafunds(amount, dest)
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/siafunds: " + err.Error()}, http.StatusInternalServerError)
		return
	}
	var txids []types.TransactionID
	for _, txn := range txns {
		txids = append(txids, txn.ID())
	}
	WriteJSON(w, WalletSiafundsPOST{
		TransactionIDs: txids,
	})
}

// walletSweepSeedHandler handles API calls to /wallet/sweep/seed.
func (api *API) walletSweepSeedHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	// Get the seed using the ditionary + phrase
	dictID := mnemonics.DictionaryID(req.FormValue("dictionary"))
	if dictID == "" {
		dictID = "english"
	}
	seed, err := modules.StringToSeed(req.FormValue("seed"), dictID)
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/sweep/seed: " + err.Error()}, http.StatusBadRequest)
		return
	}

	coins, funds, err := api.wallet.SweepSeed(seed)
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/sweep/seed: " + err.Error()}, http.StatusBadRequest)
		return
	}
	WriteJSON(w, WalletSweepPOST{
		Coins: coins,
		Funds: funds,
	})
}

// walletTransactionHandler handles API calls to /wallet/transaction/:id.
func (api *API) walletTransactionHandler(w http.ResponseWriter, req *http.Request, ps httprouter.Params) {
	// Parse the id from the url.
	var id types.TransactionID
	jsonID := "\"" + ps.ByName("id") + "\""
	err := id.UnmarshalJSON([]byte(jsonID))
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/history: " + err.Error()}, http.StatusBadRequest)
		return
	}

	txn, ok := api.wallet.Transaction(id)
	if !ok {
		WriteError(w, Error{"error when calling /wallet/transaction/:id  :  transaction not found"}, http.StatusBadRequest)
		return
	}
	WriteJSON(w, WalletTransactionGETid{
		Transaction: txn,
	})
}

// walletTransactionsHandler handles API calls to /wallet/transactions.
func (api *API) walletTransactionsHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	startheightStr, endheightStr := req.FormValue("startheight"), req.FormValue("endheight")
	if startheightStr == "" || endheightStr == "" {
		WriteError(w, Error{"startheight and endheight must be provided to a /wallet/transactions call."}, http.StatusBadRequest)
		return
	}
	// Get the start and end blocks.
	start, err := strconv.Atoi(startheightStr)
	if err != nil {
		WriteError(w, Error{"parsing integer value for parameter `startheight` failed: " + err.Error()}, http.StatusBadRequest)
		return
	}
	end, err := strconv.Atoi(endheightStr)
	if err != nil {
		WriteError(w, Error{"parsing integer value for parameter `endheight` failed: " + err.Error()}, http.StatusBadRequest)
		return
	}
	confirmedTxns, err := api.wallet.Transactions(types.BlockHeight(start), types.BlockHeight(end))
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/transactions: " + err.Error()}, http.StatusBadRequest)
		return
	}
	unconfirmedTxns := api.wallet.UnconfirmedTransactions()

	WriteJSON(w, WalletTransactionsGET{
		ConfirmedTransactions:   confirmedTxns,
		UnconfirmedTransactions: unconfirmedTxns,
	})
}

// walletTransactionsAddrHandler handles API calls to
// /wallet/transactions/:addr.
func (api *API) walletTransactionsAddrHandler(w http.ResponseWriter, req *http.Request, ps httprouter.Params) {
	// Parse the address being input.
	jsonAddr := "\"" + ps.ByName("addr") + "\""
	var addr types.UnlockHash
	err := addr.UnmarshalJSON([]byte(jsonAddr))
	if err != nil {
		WriteError(w, Error{"error when calling /wallet/transactions: " + err.Error()}, http.StatusBadRequest)
		return
	}

	confirmedATs := api.wallet.AddressTransactions(addr)
	unconfirmedATs := api.wallet.AddressUnconfirmedTransactions(addr)
	WriteJSON(w, WalletTransactionsGETaddr{
		ConfirmedTransactions:   confirmedATs,
		UnconfirmedTransactions: unconfirmedATs,
	})
}

// walletUnlockHandler handles API calls to /wallet/unlock.
func (api *API) walletUnlockHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	potentialKeys := encryptionKeys(req.FormValue("encryptionpassword"))
	for _, key := range potentialKeys {
		err := api.wallet.Unlock(key)
		if err == nil {
			WriteSuccess(w)
			return
		}
		if err != nil && err != modules.ErrBadEncryptionKey {
			WriteError(w, Error{"error when calling /wallet/unlock: " + err.Error()}, http.StatusBadRequest)
			return
		}
	}
	WriteError(w, Error{"error when calling /wallet/unlock: " + modules.ErrBadEncryptionKey.Error()}, http.StatusBadRequest)
}

// walletChangePasswordHandler handles API calls to /wallet/changepassword
func (api *API) walletChangePasswordHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
	var newKey crypto.TwofishKey
	newPassword := req.FormValue("newpassword")
	if newPassword == "" {
		WriteError(w, Error{"a password must be provided to newpassword"}, http.StatusBadRequest)
		return
	}
	newKey = crypto.TwofishKey(crypto.HashObject(newPassword))

	originalKeys := encryptionKeys(req.FormValue("encryptionpassword"))
	for _, key := range originalKeys {
		err := api.wallet.ChangeKey(key, newKey)
		if err == nil {
			WriteSuccess(w)
			return
		}
		if err != nil && err != modules.ErrBadEncryptionKey {
			WriteError(w, Error{"error when calling /wallet/changepassword: " + err.Error()}, http.StatusBadRequest)
			return
		}
	}
	WriteError(w, Error{"error when calling /wallet/changepassword: " + modules.ErrBadEncryptionKey.Error()}, http.StatusBadRequest)
}

// walletVerifyAddressHandler handles API calls to /wallet/verify/address/:addr.
func (api *API) walletVerifyAddressHandler(w http.ResponseWriter, req *http.Request, ps httprouter.Params) {
	addrString := ps.ByName("addr")

	err := new(types.UnlockHash).LoadString(addrString)
	WriteJSON(w, WalletVerifyAddressGET{Valid: err == nil})
}