handle.go

package lnurl

import (
	"errors"
	"io"
	"net/url"
	"strings"

	"github.com/tidwall/gjson"
)

// HandleLNURL takes a bech32-encoded lnurl and either gets its parameters from the query-
// string or calls the URL to get the parameters.
// Returns a different struct for each of the lnurl subprotocols, the .LNURLKind() method of
// which should be checked next to see how the wallet is going to proceed.
func HandleLNURL(rawlnurl string) (string, LNURLParams, error) {
	var err error
	var rawurl string

	if name, domain, ok := ParseInternetIdentifier(rawlnurl); ok {
		isOnion := strings.Index(domain, ".onion") == len(domain)-6
		rawurl = domain + "/.well-known/lnurlp/" + name
		if isOnion {
			rawurl = "http://" + rawurl
		} else {
			rawurl = "https://" + rawurl
		}
	} else if strings.HasPrefix(rawlnurl, "http") {
		rawurl = rawlnurl
	} else if strings.HasPrefix(rawlnurl, "lnurlp://") ||
		strings.HasPrefix(rawlnurl, "lnurlw://") ||
		strings.HasPrefix(rawlnurl, "lnurla://") ||
		strings.HasPrefix(rawlnurl, "keyauth://") {

		scheme := "https:"
		if strings.Contains(rawlnurl, ".onion/") || strings.HasSuffix(rawlnurl, ".onion") {
			scheme = "http:"
		}
		location := strings.SplitN(rawlnurl, ":", 2)[1]
		rawurl = scheme + location
	} else {
		lnurl, ok := FindLNURLInText(rawlnurl)
		if !ok {
			return "", nil,
				errors.New("invalid bech32-encoded lnurl: " + rawlnurl)
		}
		rawurl, err = LNURLDecode(lnurl)
		if err != nil {
			return "", nil, err
		}
	}

	parsed, err := url.Parse(rawurl)
	if err != nil {
		return rawurl, nil, err
	}

	query := parsed.Query()

	switch query.Get("tag") {
	case "login":
		value, err := HandleAuth(rawurl, parsed, query)
		return rawurl, value, err
	case "withdrawRequest":
		if value, ok := HandleFastWithdraw(query); ok {
			return rawurl, value, nil
		}
	}

	resp, err := actualClient.Get(rawurl)
	if err != nil {
		return rawurl, nil, err
	}

	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return rawurl, nil, err
	}

	j := gjson.ParseBytes(b)
	if j.Get("status").String() == "ERROR" {
		return rawurl, nil, LNURLErrorResponse{
			URL:    parsed,
			Reason: j.Get("reason").String(),
			Status: "ERROR",
		}
	}

	switch j.Get("tag").String() {
	case "withdrawRequest":
		value, err := HandleWithdraw(b)
		return rawurl, value, err
	case "payRequest":
		value, err := HandlePay(b)
		return rawurl, value, err
	case "channelRequest":
		value, err := HandleChannel(b)
		return rawurl, value, err
	default:
		return rawurl, nil, errors.New("unknown response tag " + j.String())
	}
}