amethyst/app/src/main/java/com/vitorpamplona/amethyst/service/CashuProcessor.kt

101 wiersze
3.6 KiB
Kotlin

package com.vitorpamplona.amethyst.service
import androidx.compose.runtime.Immutable
import com.fasterxml.jackson.databind.JsonNode
import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
import com.vitorpamplona.amethyst.service.lnurl.LightningAddressResolver
import com.vitorpamplona.amethyst.ui.components.GenericLoadable
import com.vitorpamplona.quartz.events.Event
import okhttp3.MediaType.Companion.toMediaType
import okhttp3.Request
import okhttp3.RequestBody.Companion.toRequestBody
import java.util.Base64
@Immutable
data class CashuToken(
val token: String,
val mint: String,
val totalAmount: Long,
val fees: Int,
val redeemInvoiceAmount: Long,
val proofs: JsonNode
)
class CashuProcessor {
fun parse(cashuToken: String): GenericLoadable<CashuToken> {
checkNotInMainThread()
try {
val base64token = cashuToken.replace("cashuA", "")
val cashu = jacksonObjectMapper().readTree(String(Base64.getDecoder().decode(base64token)))
val token = cashu.get("token").get(0)
val proofs = token.get("proofs")
val mint = token.get("mint").asText()
var totalAmount = 0L
for (proof in proofs) {
totalAmount += proof.get("amount").asLong()
}
val fees = Math.max(((totalAmount * 0.02).toInt()), 2)
val redeemInvoiceAmount = totalAmount - fees
return GenericLoadable.Loaded(CashuToken(cashuToken, mint, totalAmount, fees, redeemInvoiceAmount, proofs))
} catch (e: Exception) {
return GenericLoadable.Error<CashuToken>("Could not parse this cashu token")
}
}
fun melt(token: CashuToken, lud16: String, onSuccess: (String) -> Unit, onError: (String) -> Unit) {
checkNotInMainThread()
runCatching {
LightningAddressResolver().lnAddressInvoice(
lnaddress = lud16,
milliSats = token.redeemInvoiceAmount * 1000, // Make invoice and leave room for fees
message = "Redeem Cashu",
onSuccess = { invoice ->
meltInvoice(token, invoice, onSuccess, onError)
},
onProgress = {
},
onError = onError
)
}
}
private fun meltInvoice(token: CashuToken, invoice: String, onSuccess: (String) -> Unit, onError: (String) -> Unit) {
try {
val client = HttpClient.getHttpClient()
val url = token.mint + "/melt" // Melt cashu tokens at Mint
val factory = Event.mapper.nodeFactory
val jsonObject = factory.objectNode()
jsonObject.put("proofs", token.proofs)
jsonObject.put("pr", invoice)
val mediaType = "application/json; charset=utf-8".toMediaType()
val requestBody = jsonObject.toString().toRequestBody(mediaType)
val request = Request.Builder()
.url(url)
.post(requestBody)
.build()
client.newCall(request).execute().use {
val body = it.body.string()
val tree = jacksonObjectMapper().readTree(body)
val successful = tree?.get("paid")?.asText() == "true"
if (successful) {
onSuccess("Redeemed ${token.totalAmount} Sats" + " (Fees: ${token.fees} Sats)")
} else {
onError(tree?.get("detail")?.asText()?.split('.')?.getOrNull(0) ?: "Cashu: Tokens already spent.")
}
}
} catch (e: Exception) {
onError("Token melt failure: " + e.message)
}
}
}