From 2a4ee6c48c55eaf400a6e109f00820e9d60b3921 Mon Sep 17 00:00:00 2001
From: William Casarin <jb55@jb55.com>
Date: Mon, 17 Jul 2023 14:12:41 -0700
Subject: [PATCH] zaps: don't spam lnurls when validate zaps

lnurls.lookup_or_fetch not fetched lnurl1dp68gurn8ghj7um9dej8xct5wvhxcmmv9uh8wetvdskkkmn0wahz7mrww4excup0df3r2dg3mj444
fetching static payreq lnurl1dp68gurn8ghj7um9dej8xct5wvhxcmmv9uh8wetvdskkkmn0wahz7mrww4excup0df3r2dg3mj444
lnurls.lookup_or_fetch already fetching lnurl1dp68gurn8ghj7um9dej8xct5wvhxcmmv9uh8wetvdskkkmn0wahz7mrww4excup0df3r2dg3mj444
lnurls.lookup_or_fetch already fetching lnurl1dp68gurn8ghj7um9dej8xct5wvhxcmmv9uh8wetvdskkkmn0wahz7mrww4excup0df3r2dg3mj444
lnurls.lookup_or_fetch already fetching lnurl1dp68gurn8ghj7um9dej8xct5wvhxcmmv9uh8wetvdskkkmn0wahz7mrww4excup0df3r2dg3mj444
lnurls.lookup_or_fetch already fetching lnurl1dp68gurn8ghj7um9dej8xct5wvhxcmmv9uh8wetvdskkkmn0wahz7mrww4excup0df3r2dg3mj444

Changelog-Fixed: Don't spam lnurls when validating zaps
---
 damus/Models/HomeModel.swift |  4 +--
 damus/Util/LNUrls.swift      | 53 ++++++++++++++++++++++++++++++++----
 damus/Util/Zap.swift         |  7 +++--
 damus/Util/Zaps.swift        |  2 +-
 4 files changed, 56 insertions(+), 10 deletions(-)

diff --git a/damus/Models/HomeModel.swift b/damus/Models/HomeModel.swift
index 5efdbbb9..ffc410d9 100644
--- a/damus/Models/HomeModel.swift
+++ b/damus/Models/HomeModel.swift
@@ -1390,9 +1390,9 @@ func process_zap_event(damus_state: DamusState, ev: NostrEvent, completion: @esc
         completion(.failed)
         return
     }
-    
+
     Task {
-        guard let zapper = await fetch_zapper_from_lnurl(lnurl) else {
+        guard let zapper = await fetch_zapper_from_lnurl(lnurls: damus_state.lnurls, pubkey: ptag, lnurl: lnurl) else {
             completion(.failed)
             return
         }
diff --git a/damus/Util/LNUrls.swift b/damus/Util/LNUrls.swift
index 91b4af41..a5c45c6a 100644
--- a/damus/Util/LNUrls.swift
+++ b/damus/Util/LNUrls.swift
@@ -7,14 +7,57 @@
 
 import Foundation
 
+enum LNUrlState {
+    case not_fetched
+    case fetching(Task<LNUrlPayRequest?, Never>)
+    case fetched(LNUrlPayRequest)
+    case failed(tries: Int)
+}
+
 class LNUrls {
-    var endpoints: [String: LNUrlPayRequest]
-    
+    var endpoints: [String: LNUrlState]
+
     init() {
         self.endpoints = [:]
     }
-    
-    func lookup(_ id: String) -> LNUrlPayRequest? {
-        return self.endpoints[id]
+
+    @MainActor
+    func lookup_or_fetch(pubkey: String, lnurl: String) async -> LNUrlPayRequest? {
+        switch lookup(pubkey: pubkey) {
+        case .failed(let tries):
+            print("lnurls.lookup_or_fetch failed \(tries) \(lnurl)")
+            guard tries < 5 else { return nil }
+            self.endpoints[pubkey] = .failed(tries: tries + 1)
+        case .fetched(let pr):
+            print("lnurls.lookup_or_fetch fetched \(lnurl)")
+            return pr
+        case .fetching(let task):
+            print("lnurls.lookup_or_fetch already fetching \(lnurl)")
+            return await task.value
+        case .not_fetched:
+            print("lnurls.lookup_or_fetch not fetched \(lnurl)")
+            break
+        }
+
+        let task = Task {
+            let v = await fetch_static_payreq(lnurl)
+            return v
+        }
+
+        self.endpoints[pubkey] = .fetching(task)
+
+        let v = await task.value
+
+        if let v {
+            self.endpoints[pubkey] = .fetched(v)
+        } else {
+            self.endpoints[pubkey] = .failed(tries: 1)
+        }
+
+        return v
+    }
+
+    func lookup(pubkey: String) -> LNUrlState {
+        return self.endpoints[pubkey] ?? .not_fetched
     }
 }
diff --git a/damus/Util/Zap.swift b/damus/Util/Zap.swift
index 664cbe77..747f8bde 100644
--- a/damus/Util/Zap.swift
+++ b/damus/Util/Zap.swift
@@ -412,8 +412,9 @@ func decode_nostr_event_json(_ desc: String) -> NostrEvent? {
     return ev
 }
 
-func fetch_zapper_from_lnurl(_ lnurl: String) async -> String? {
-    guard let endpoint = await fetch_static_payreq(lnurl) else {
+
+func fetch_zapper_from_lnurl(lnurls: LNUrls, pubkey: String, lnurl: String) async -> String? {
+    guard let endpoint = await lnurls.lookup_or_fetch(pubkey: pubkey, lnurl: lnurl) else {
         return nil
     }
     
@@ -442,6 +443,8 @@ func decode_lnurl(_ lnurl: String) -> URL? {
 }
 
 func fetch_static_payreq(_ lnurl: String) async -> LNUrlPayRequest? {
+    print("fetching static payreq \(lnurl)")
+
     guard let url = decode_lnurl(lnurl) else {
         return nil
     }
diff --git a/damus/Util/Zaps.swift b/damus/Util/Zaps.swift
index 6605d69d..698e0dcc 100644
--- a/damus/Util/Zaps.swift
+++ b/damus/Util/Zaps.swift
@@ -11,7 +11,7 @@ class Zaps {
     private(set) var zaps: [String: Zapping]
     let our_pubkey: String
     var our_zaps: [String: [Zapping]]
-    
+
     private(set) var event_counts: [String: Int]
     private(set) var event_totals: [String: Int64]