adds support for NIP-75 events

quartz/src/main/java/com/vitorpamplona/quartz/events/GoalEvent.kt

@@ -0,0 +1,62 @@
+package com.vitorpamplona.quartz.events
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.utils.TimeUtils
+import com.vitorpamplona.quartz.encoders.toHexKey
+import com.vitorpamplona.quartz.crypto.CryptoUtils
+import com.vitorpamplona.quartz.encoders.ATag
+import com.vitorpamplona.quartz.encoders.HexKey
+import com.vitorpamplona.quartz.signers.NostrSigner
+
+@Immutable
+class GoalEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey
+) : BaseAddressableEvent(id, pubKey, createdAt, kind, tags, content, sig) {
+    companion object {
+        const val kind = 9041
+        const val alt = "Zap Goal"
+
+        private const val SUMMARY = "summary"
+        private const val CLOSED_AT = "closed_at"
+        private const val IMAGE = "image"
+        private const val AMOUNT = "amount"
+
+        fun create(
+            description: String,
+            amount: Long,
+            relays: Set<String>,
+            closedAt: Long? = null,
+            image: String? = null,
+            summary: String? = null,
+            websiteUrl: String? = null,
+            linkedEvent: Event? = null,
+            signer: NostrSigner,
+            createdAt: Long = TimeUtils.now(),
+            onReady: (GoalEvent) -> Unit
+        ) {
+            var tags = mutableListOf(
+                arrayOf(AMOUNT, amount.toString()),
+                arrayOf("relays") + relays,
+                arrayOf("alt", alt)
+            )
+
+            if (linkedEvent is AddressableEvent) {
+                tags.add(arrayOf("a", linkedEvent.address().toTag()))
+            } else if (linkedEvent is Event) {
+                tags.add(arrayOf("e", linkedEvent.id))
+            }
+
+            closedAt?.let { tags.add(arrayOf(CLOSED_AT, it.toString())) }
+            summary?.let { tags.add(arrayOf(SUMMARY, it)) }
+            image?.let { tags.add(arrayOf(IMAGE, it)) }
+            websiteUrl?.let { tags.add(arrayOf("r", it)) }
+
+            signer.sign(createdAt, kind, tags.toTypedArray(), description, onReady)
+        }
+    }
+}