package phoenixd

import (
	"context"
	b64 "encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"

	decodepay "github.com/nbd-wtf/ln-decodepay"

	"github.com/getAlby/hub/lnclient"
	"github.com/getAlby/hub/logger"

	"github.com/sirupsen/logrus"
)

// errNotFound indicates that a payment was not found at the queried endpoint.
var errNotFound = errors.New("phoenixd: payment not found")

type InvoiceResponse struct {
	PaymentHash string `json:"paymentHash"`
	Preimage    string `json:"preimage"`
	ExternalId  string `json:"externalId"`
	Description string `json:"description"`
	Invoice     string `json:"invoice"`
	IsPaid      bool   `json:"isPaid"`
	ReceivedSat int64  `json:"receivedSat"`
	FeesSat     int64  `json:"fees"`
	CompletedAt int64  `json:"completedAt"`
	CreatedAt   int64  `json:"createdAt"`
}

type OutgoingPaymentResponse struct {
	PaymentHash string `json:"paymentHash"`
	Preimage    string `json:"preimage"`
	Invoice     string `json:"invoice"`
	IsPaid      bool   `json:"isPaid"`
	Sent        int64  `json:"sent"`
	Fees        int64  `json:"fees"`
	CompletedAt int64  `json:"completedAt"`
	CreatedAt   int64  `json:"createdAt"`
}

type PayResponse struct {
	PaymentHash     string `json:"paymentHash"`
	PaymentId       string `json:"paymentId"`
	PaymentPreimage string `json:"paymentPreimage"`
	RoutingFeeSat   int64  `json:"routingFeeSat"`
}

type MakeInvoiceResponse struct {
	AmountSat   int64  `json:"amountSat"`
	PaymentHash string `json:"paymentHash"`
	Serialized  string `json:"serialized"`
}

type InfoResponse struct {
	NodeId string `json:"nodeId"`
}

type BalanceResponse struct {
	BalanceSat   int64 `json:"balanceSat"`
	FeeCreditSat int64 `json:"feeCreditSat"`
}

type PhoenixService struct {
	Address       string
	Authorization string
	pubkey        string
	nodeInfo      *lnclient.NodeInfo
	ctx           context.Context
}

func NewPhoenixService(ctx context.Context, address string, authorization string) (result lnclient.LNClient, err error) {
	authorizationBase64 := b64.StdEncoding.EncodeToString([]byte(":" + authorization))
	// some environments (e.g. in a cloud environment like render.com) can only get the address and the port but not the protocol
	// in those cases we default to http for local requests
	if !strings.HasPrefix(address, "http") {
		address = "http://" + address
	}
	phoenixService := &PhoenixService{ctx: ctx, Address: address, Authorization: authorizationBase64}

	info, err := fetchNodeInfo(ctx, phoenixService)
	if err != nil {
		return nil, err
	}
	phoenixService.nodeInfo = info
	phoenixService.pubkey = info.Pubkey

	return phoenixService, nil
}

func (svc *PhoenixService) GetBalances(ctx context.Context, includeInactiveChannels bool) (*lnclient.BalancesResponse, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, svc.Address+"/getbalance", nil)
	if err != nil {
		return nil, err
	}
	req.Header.Add("Authorization", "Basic "+svc.Authorization)
	client := &http.Client{Timeout: 5 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != http.StatusOK {
		logger.Logger.WithFields(logrus.Fields{
			"body":        string(body),
			"status_code": resp.StatusCode,
		}).Error("phoenixd get balance endpoint returned non-success code")
		return nil, fmt.Errorf("phoenixd get balance endpoint returned non-success code: %d %s", resp.StatusCode, string(body))
	}

	var balanceRes BalanceResponse
	if err := json.Unmarshal(body, &balanceRes); err != nil {
		return nil, err
	}

	balance := balanceRes.BalanceSat * 1000

	return &lnclient.BalancesResponse{
		Onchain: lnclient.OnchainBalanceResponse{
			PendingBalancesDetails:      []lnclient.PendingBalanceDetails{},
			PendingSweepBalancesDetails: []lnclient.PendingBalanceDetails{}},
		Lightning: lnclient.LightningBalanceResponse{
			TotalSpendableMsat:      balance,
			NextMaxSpendableMsat:    balance,
			NextMaxSpendableMPPMsat: balance,
		},
	}, nil
}

func (svc *PhoenixService) GetInfo(ctx context.Context) (info *lnclient.NodeInfo, err error) {
	return svc.nodeInfo, nil
}

func fetchNodeInfo(ctx context.Context, svc *PhoenixService) (info *lnclient.NodeInfo, err error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, svc.Address+"/getinfo", nil)
	if err != nil {
		return nil, err
	}
	req.Header.Add("Authorization", "Basic "+svc.Authorization)
	client := &http.Client{Timeout: 5 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != http.StatusOK {
		logger.Logger.WithFields(logrus.Fields{
			"body":        string(body),
			"status_code": resp.StatusCode,
		}).Error("phoenixd get info endpoint returned non-success code")
		return nil, fmt.Errorf("phoenixd get info endpoint returned non-success code: %d %s", resp.StatusCode, string(body))
	}

	var infoRes InfoResponse
	if err := json.Unmarshal(body, &infoRes); err != nil {
		return nil, err
	}
	return &lnclient.NodeInfo{
		Alias:       "Phoenix",
		Color:       "",
		Pubkey:      infoRes.NodeId,
		Network:     "bitcoin",
		BlockHeight: 0,
		BlockHash:   "",
	}, nil
}

func (svc *PhoenixService) ListChannels(ctx context.Context) ([]lnclient.Channel, error) {
	channels := []lnclient.Channel{}
	return channels, nil
}

func (svc *PhoenixService) MakeInvoice(ctx context.Context, amountMsat int64, description string, descriptionHash string, expiry int64, throughNodePubkey *string) (transaction *lnclient.Transaction, err error) {
	// TODO: support expiry
	if expiry == 0 {
		expiry = lnclient.DEFAULT_INVOICE_EXPIRY
	}
	form := url.Values{}
	amountSat := strconv.FormatInt(amountMsat/1000, 10)
	form.Add("amountSat", amountSat)
	if description != "" {
		form.Add("description", description)
	} else if descriptionHash != "" {
		form.Add("descriptionHash", descriptionHash)
	} else {
		form.Add("description", "invoice")
	}

	today := time.Now().UTC().Format("2006-02-01") // querying is too slow so we limit the invoices we query with the date - see list transactions
	form.Add("externalId", today)                  // for some resone phoenixd requires an external id to query a list of invoices. thus we set this to nwc
	logger.Logger.WithFields(logrus.Fields{
		"externalId": today,
		"amountSat":  amountSat,
	}).Infof("Requesting phoenix invoice")
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, svc.Address+"/createinvoice", strings.NewReader(form.Encode()))
	if err != nil {
		return nil, err
	}
	req.Header.Add("Authorization", "Basic "+svc.Authorization)
	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != http.StatusOK {
		logger.Logger.WithFields(logrus.Fields{
			"body":        string(body),
			"status_code": resp.StatusCode,
		}).Error("phoenixd create invoice endpoint returned non-success code")
		return nil, fmt.Errorf("phoenixd create invoice endpoint returned non-success code: %d %s", resp.StatusCode, string(body))
	}

	var invoiceRes MakeInvoiceResponse
	if err := json.Unmarshal(body, &invoiceRes); err != nil {
		return nil, err
	}

	tx, err := svc.LookupInvoice(ctx, invoiceRes.PaymentHash)
	if err != nil {
		logger.Logger.WithError(err).Error("failed to lookup newly created invoice")
		return nil, err
	}

	return tx, nil
}

func (svc *PhoenixService) MakeHoldInvoice(ctx context.Context, amountMsat int64, description string, descriptionHash string, expiry int64, paymentHash string, minCltvExpiryDelta *uint64) (transaction *lnclient.Transaction, err error) {
	return nil, errors.New("not implemented")
}

func (svc *PhoenixService) SettleHoldInvoice(ctx context.Context, preimage string) (err error) {
	return errors.New("not implemented")
}

func (svc *PhoenixService) CancelHoldInvoice(ctx context.Context, paymentHash string) (err error) {
	return errors.New("not implemented")
}

// LookupInvoice looks up a transaction by payment hash. It first checks
// incoming payments, then falls back to outgoing payments if the incoming
// payment is not found (HTTP 404).
func (svc *PhoenixService) LookupInvoice(ctx context.Context, paymentHash string) (transaction *lnclient.Transaction, err error) {
	transaction, err = svc.lookupIncomingPayment(ctx, paymentHash)
	if err == nil {
		return transaction, nil
	}

	// Only fall back to outgoing lookup when incoming returns not-found.
	if !errors.Is(err, errNotFound) {
		return nil, err
	}

	return svc.lookupOutgoingPayment(ctx, paymentHash)
}

// lookupIncomingPayment fetches an incoming payment from Phoenixd by payment hash.
func (svc *PhoenixService) lookupIncomingPayment(ctx context.Context, paymentHash string) (*lnclient.Transaction, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, svc.Address+"/payments/incoming/"+paymentHash, nil)
	if err != nil {
		return nil, fmt.Errorf("create phoenixd incoming payment request: %w", err)
	}
	req.Header.Add("Authorization", "Basic "+svc.Authorization)
	client := &http.Client{Timeout: 5 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("call phoenixd incoming payment endpoint: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("read phoenixd incoming payment response: %w", err)
	}
	if resp.StatusCode == http.StatusNotFound {
		return nil, errNotFound
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("phoenixd incoming payments endpoint returned non-success code: %d %s", resp.StatusCode, string(body))
	}

	var invoiceRes InvoiceResponse
	if err := json.Unmarshal(body, &invoiceRes); err != nil {
		return nil, fmt.Errorf("decode phoenixd incoming payment response: %w", err)
	}

	return phoenixInvoiceToTransaction(&invoiceRes)
}

// lookupOutgoingPayment fetches an outgoing payment from Phoenixd using the
// /payments/outgoingbyhash/{paymentHash} endpoint.
func (svc *PhoenixService) lookupOutgoingPayment(ctx context.Context, paymentHash string) (*lnclient.Transaction, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, svc.Address+"/payments/outgoingbyhash/"+paymentHash, nil)
	if err != nil {
		return nil, fmt.Errorf("create phoenixd outgoing payment request: %w", err)
	}
	req.Header.Add("Authorization", "Basic "+svc.Authorization)
	client := &http.Client{Timeout: 5 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("call phoenixd outgoing payment endpoint: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("read phoenixd outgoing payment response: %w", err)
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("phoenixd outgoing payment lookup returned non-success code: %d %s", resp.StatusCode, string(body))
	}

	var paymentRes OutgoingPaymentResponse
	if err := json.Unmarshal(body, &paymentRes); err != nil {
		return nil, fmt.Errorf("decode phoenixd outgoing payment response: %w", err)
	}

	return outgoingPaymentToTransaction(&paymentRes)
}

func (svc *PhoenixService) SendPaymentSync(payReq string, amountMsat *uint64) (*lnclient.PayInvoiceResponse, error) {
	// TODO: support 0-amount invoices
	if amountMsat != nil {
		return nil, errors.New("0-amount invoices not supported")
	}
	form := url.Values{}
	form.Add("invoice", payReq)
	req, err := http.NewRequestWithContext(svc.ctx, http.MethodPost, svc.Address+"/payinvoice", strings.NewReader(form.Encode()))
	if err != nil {
		return nil, err
	}
	req.Header.Add("Authorization", "Basic "+svc.Authorization)
	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
	client := &http.Client{Timeout: 90 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("phoenixd /payinvoice returned non-success status: %d %s", resp.StatusCode, string(body))
	}

	var payRes PayResponse
	if err := json.Unmarshal(body, &payRes); err != nil {
		return nil, err
	}

	return &lnclient.PayInvoiceResponse{
		Preimage: payRes.PaymentPreimage,
		FeeMsat:  uint64(payRes.RoutingFeeSat) * 1000,
	}, nil
}

func (svc *PhoenixService) SendKeysend(amountMsat uint64, destination string, custom_records []lnclient.TLVRecord, preimage string) (*lnclient.PayKeysendResponse, error) {
	return nil, errors.New("not implemented")
}

func (svc *PhoenixService) RedeemOnchainFunds(ctx context.Context, toAddress string, amountSat uint64, feeRate *uint64, sendAll bool) (txId string, err error) {
	return "", errors.New("not implemented")
}

func (svc *PhoenixService) ResetRouter(key string) error {
	return errors.New("not implemented")
}

func (svc *PhoenixService) Shutdown() error {
	// No specific shutdown actions needed for Phoenixd client via HTTP
	return nil
}

func (svc *PhoenixService) GetNodeConnectionInfo(ctx context.Context) (nodeConnectionInfo *lnclient.NodeConnectionInfo, err error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, svc.Address+"/getinfo", nil)
	if err != nil {
		return nil, err
	}
	req.Header.Add("Authorization", "Basic "+svc.Authorization)
	client := &http.Client{Timeout: 5 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("phoenixd /getinfo returned non-success status: %d %s", resp.StatusCode, string(body))
	}

	var infoRes InfoResponse
	if err := json.Unmarshal(body, &infoRes); err != nil {
		return nil, err
	}
	return &lnclient.NodeConnectionInfo{
		Pubkey: infoRes.NodeId,
	}, nil
}

func (svc *PhoenixService) ConnectPeer(ctx context.Context, connectPeerRequest *lnclient.ConnectPeerRequest) error {
	return errors.New("not implemented")
}
func (svc *PhoenixService) OpenChannel(ctx context.Context, openChannelRequest *lnclient.OpenChannelRequest) (*lnclient.OpenChannelResponse, error) {
	return nil, errors.New("not implemented")
}

func (svc *PhoenixService) CloseChannel(ctx context.Context, closeChannelRequest *lnclient.CloseChannelRequest) error {
	return errors.New("not implemented")
}

func (svc *PhoenixService) GetNewOnchainAddress(ctx context.Context) (string, error) {
	return "", errors.New("not implemented")
}

func (svc *PhoenixService) GetOnchainBalance(ctx context.Context) (*lnclient.OnchainBalanceResponse, error) {
	return nil, errors.New("not implemented")
}

func (svc *PhoenixService) SignMessage(ctx context.Context, message string) (string, error) {
	return "", errors.New("not implemented")
}

func (svc *PhoenixService) ListPeers(ctx context.Context) ([]lnclient.PeerDetails, error) {
	return nil, nil
}

func (svc *PhoenixService) GetLogOutput(ctx context.Context, maxLen int) ([]byte, error) {
	return []byte{}, nil
}

func (svc *PhoenixService) GetNodeStatus(ctx context.Context) (nodeStatus *lnclient.NodeStatus, err error) {
	_, err = fetchNodeInfo(ctx, svc)
	if err != nil {
		return nil, err
	}

	return &lnclient.NodeStatus{
		IsReady: true,
	}, nil
}

func (svc *PhoenixService) GetStorageDir() (string, error) {
	return "", nil
}

func (svc *PhoenixService) GetNetworkGraph(ctx context.Context, nodeIds []string) (lnclient.NetworkGraphResponse, error) {
	return nil, nil
}

func (svc *PhoenixService) UpdateLastWalletSyncRequest() {}

func (svc *PhoenixService) DisconnectPeer(ctx context.Context, peerId string) error {
	return errors.New("not implemented")
}

func (svc *PhoenixService) UpdateChannel(ctx context.Context, updateChannelRequest *lnclient.UpdateChannelRequest) error {
	return errors.New("not implemented")
}

func (svc *PhoenixService) GetSupportedNIP47Methods() []string {
	return []string{"pay_invoice", "get_balance", "get_budget", "get_info", "make_invoice", "lookup_invoice", "list_transactions", "multi_pay_invoice"}
}

func (svc *PhoenixService) GetSupportedNIP47NotificationTypes() []string {
	return []string{}
}

func (svc *PhoenixService) GetPubkey() string {
	return svc.pubkey
}

func phoenixInvoiceToTransaction(invoiceRes *InvoiceResponse) (*lnclient.Transaction, error) {
	var settledAt *int64
	if invoiceRes.CompletedAt != 0 {
		settledAtUnix := time.UnixMilli(invoiceRes.CompletedAt).Unix()
		settledAt = &settledAtUnix
	}

	paymentRequest, err := decodepay.Decodepay(invoiceRes.Invoice)
	if err != nil {
		logger.Logger.WithFields(logrus.Fields{
			"bolt11": invoiceRes.Invoice,
		}).Errorf("Failed to decode bolt11 invoice: %v", err)

		return nil, err
	}

	expiresAt := time.UnixMilli(int64(paymentRequest.CreatedAt) * 1000).Add(time.Duration(paymentRequest.Expiry) * time.Second).Unix()

	return &lnclient.Transaction{
		Type:            "incoming",
		Invoice:         invoiceRes.Invoice,
		Preimage:        invoiceRes.Preimage,
		PaymentHash:     invoiceRes.PaymentHash,
		AmountMsat:      paymentRequest.MSatoshi,
		FeesPaidMsat:    invoiceRes.FeesSat * 1000,
		CreatedAt:       time.UnixMilli(invoiceRes.CreatedAt).Unix(),
		Description:     invoiceRes.Description,
		SettledAt:       settledAt,
		ExpiresAt:       &expiresAt,
		DescriptionHash: paymentRequest.DescriptionHash,
	}, nil
}

// outgoingPaymentToTransaction converts a Phoenixd OutgoingPaymentResponse
// to an lnclient.Transaction.
func outgoingPaymentToTransaction(payment *OutgoingPaymentResponse) (*lnclient.Transaction, error) {
	var settledAt *int64
	if payment.CompletedAt != 0 {
		settledAtUnix := time.UnixMilli(payment.CompletedAt).Unix()
		settledAt = &settledAtUnix
	}

	paymentRequest, err := decodepay.Decodepay(payment.Invoice)
	if err != nil {
		logger.Logger.WithFields(logrus.Fields{
			"bolt11": payment.Invoice,
		}).Errorf("Failed to decode bolt11 invoice: %v", err)
		return nil, fmt.Errorf("decode phoenixd outgoing payment bolt11: %w", err)
	}

	expiresAt := time.UnixMilli(int64(paymentRequest.CreatedAt) * 1000).Add(time.Duration(paymentRequest.Expiry) * time.Second).Unix()

	// unlike incoming payments, "fees" on outgoing payments is in millisats,
	// and "sent" (in sats) includes the fees
	amountMsat := paymentRequest.MSatoshi
	if amountMsat == 0 {
		amountMsat = payment.Sent*1000 - payment.Fees
	}

	return &lnclient.Transaction{
		Type:            "outgoing",
		Invoice:         payment.Invoice,
		Preimage:        payment.Preimage,
		PaymentHash:     payment.PaymentHash,
		AmountMsat:      amountMsat,
		FeesPaidMsat:    payment.Fees,
		CreatedAt:       time.UnixMilli(payment.CreatedAt).Unix(),
		Description:     paymentRequest.Description,
		SettledAt:       settledAt,
		ExpiresAt:       &expiresAt,
		DescriptionHash: paymentRequest.DescriptionHash,
	}, nil
}

func (svc *PhoenixService) GetCustomNodeCommandDefinitions() []lnclient.CustomNodeCommandDef {
	return nil
}

func (svc *PhoenixService) ExecuteCustomNodeCommand(ctx context.Context, command *lnclient.CustomNodeCommandRequest) (*lnclient.CustomNodeCommandResponse, error) {
	return nil, lnclient.ErrUnknownCustomNodeCommand
}

func (svc *PhoenixService) MakeOffer(ctx context.Context, description string) (string, error) {
	return "", errors.New("not supported")
}

func (svc *PhoenixService) ListOnchainTransactions(ctx context.Context) ([]lnclient.OnchainTransaction, error) {
	return nil, errors.ErrUnsupported
}