Meetups: a refused join reads in the phone's language

ios-native/App/Localizable.xcstrings

@@ -3826,6 +3826,26 @@
         }
       }
     },
+    "Meetup is full.": {
+      "localizations": {
+        "zh-Hans": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "这场聚会已满。"
+          }
+        }
+      }
+    },
+    "Meetup is no longer accepting participants.": {
+      "localizations": {
+        "zh-Hans": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "这场聚会已不再接受报名。"
+          }
+        }
+      }
+    },
     "Meetups": {
       "localizations": {
         "zh-Hans": {
@@ -5729,6 +5749,16 @@
         }
       }
     },
+    "Select a pet to join this meetup.": {
+      "localizations": {
+        "zh-Hans": {
+          "stringUnit": {
+            "state": "translated",
+            "value": "选一只宠物来报名这场聚会。"
+          }
+        }
+      }
+    },
     "Send": {
       "localizations": {
         "zh-Hans": {

ios-native/Features/Meetups/Meetups.swift

@@ -302,6 +302,75 @@ enum MeetupJoinOutcome: Equatable, Sendable {
     case refused(String)
 }
 
+/// The server's reason for refusing a join, in the phone's language.
+///
+/// It refuses in English sentences, one or several of a meetup's rules at
+/// once. Each one it can send is either a line `MeetupRequirements.lines`
+/// already shows before joining, or one of three of its own. They are put
+/// into the phone's language one by one. A sentence this does not know is
+/// shown as the server wrote it, rather than not at all.
+enum MeetupRefusal {
+    static func localized(_ reason: String, bundle: Bundle = .main, locale: Locale = .current) -> String {
+        var words = ""
+        for sentence in sentences(of: reason) {
+            // English sentences are spaced; Chinese ones are not.
+            if words.hasSuffix(".") { words += " " }
+            words += localized(sentence: sentence, bundle: bundle, locale: locale)
+        }
+        return words
+    }
+
+    /// The server joins its reasons with a space, each ending in a full stop.
+    static func sentences(of reason: String) -> [String] {
+        var sentences: [String] = []
+        var current = ""
+        for character in reason.trimmingCharacters(in: .whitespaces) {
+            if character == " ", current.hasSuffix(".") {
+                sentences.append(current)
+                current = ""
+            } else {
+                current.append(character)
+            }
+        }
+        if !current.isEmpty { sentences.append(current) }
+        return sentences
+    }
+
+    private static func localized(sentence: String, bundle: Bundle, locale: Locale) -> String {
+        switch sentence {
+        case "Meetup is full.":
+            return String(localized: "Meetup is full.", bundle: bundle, locale: locale)
+        case "Meetup is no longer accepting participants.":
+            return String(localized: "Meetup is no longer accepting participants.", bundle: bundle, locale: locale)
+        case "Select a pet to join this meetup.":
+            return String(localized: "Select a pet to join this meetup.", bundle: bundle, locale: locale)
+        case "Must have posted at least once.":
+            return String(localized: "Must have posted at least once.", bundle: bundle, locale: locale)
+        case "Must have a pet profile.":
+            return String(localized: "Must have a pet profile.", bundle: bundle, locale: locale)
+        case "Dogs only.":
+            return String(localized: "Dogs only.", bundle: bundle, locale: locale)
+        case "Cats only.":
+            return String(localized: "Cats only.", bundle: bundle, locale: locale)
+        case "Other pets only.":
+            return String(localized: "Other pets only.", bundle: bundle, locale: locale)
+        default:
+            // "Requires at least 3 followed pets." The server says "pets"
+            // for one as well; the app does not.
+            guard let count = followedPets(in: sentence) else { return sentence }
+            return count == 1
+                ? String(localized: "Requires at least 1 followed pet.", bundle: bundle, locale: locale)
+                : String(localized: "Requires at least \(count) followed pets.", bundle: bundle, locale: locale)
+        }
+    }
+
+    private static func followedPets(in sentence: String) -> Int? {
+        let prefix = "Requires at least ", suffix = " followed pets."
+        guard sentence.hasPrefix(prefix), sentence.hasSuffix(suffix) else { return nil }
+        return Int(sentence.dropFirst(prefix.count).dropLast(suffix.count))
+    }
+}
+
 protocol MeetupsReading: Sendable {
     func upcoming(limit: Int) async throws -> [Meetup]
     func thisWeek(from now: Date, limit: Int) async throws -> [Meetup]
@@ -426,7 +495,8 @@ actor FirestoreMeetupsSource: MeetupsReading, MeetupCreating, MeetupEditing {
         if let petID { payload["petId"] = petID }
         let answer = try await CallableClient.call(Callables.joinMeetup, payload)
         if answer["success"] as? Bool == true { return .joined }
-        return .refused(answer["error"] as? String ?? String(localized: "Couldn't join this meetup."))
+        if let reason = answer["error"] as? String { return .refused(MeetupRefusal.localized(reason)) }
+        return .refused(String(localized: "Couldn't join this meetup."))
     }
 
     func leave(meetupID: String, uid: String) async throws {

ios-native/PetNoteAppTests/PlacesMeetupsTests.swift

@@ -521,3 +521,49 @@ struct PlacesMeetupsTests {
         #expect(!model.hasMore)
     }
 }
+
+/// The server refuses a join in English sentences. The app shows them in the
+/// phone's language, one sentence at a time.
+struct MeetupRefusalTests {
+    /// A bundle with no translations in it: what English gets, whatever
+    /// language the machine running the tests is set to.
+    private final class NoTranslations {}
+    private static let english = Bundle(for: NoTranslations.self)
+    private static let zh = Locale(identifier: "zh-Hans")
+
+    private static func chinese() throws -> Bundle {
+        let path = try #require(Bundle.main.path(forResource: "zh-Hans", ofType: "lproj"), "the app was built without Chinese")
+        return try #require(Bundle(path: path))
+    }
+
+    @Test func theServersOwnRefusalsComeOutInChinese() throws {
+        let bundle = try Self.chinese()
+        #expect(MeetupRefusal.localized("Meetup is full.", bundle: bundle, locale: Self.zh) == "这场聚会已满。")
+        #expect(MeetupRefusal.localized("Meetup is no longer accepting participants.", bundle: bundle, locale: Self.zh)
+            == "这场聚会已不再接受报名。")
+        #expect(MeetupRefusal.localized("Select a pet to join this meetup.", bundle: bundle, locale: Self.zh) == "选一只宠物来报名这场聚会。")
+    }
+
+    @Test func severalRulesAtOnceAreEachPutIntoChinese() throws {
+        let words = MeetupRefusal.localized(
+            "Must have posted at least once. Requires at least 3 followed pets. Dogs only.",
+            bundle: try Self.chinese(), locale: Self.zh
+        )
+        #expect(words == "需要至少发过一条帖子。需要至少关注 3 只宠物。仅限狗。")
+    }
+
+    @Test func inEnglishTheServersWordsAreUnchanged() {
+        let reason = "Must have posted at least once. Must have a pet profile. Cats only."
+        #expect(MeetupRefusal.localized(reason, bundle: Self.english) == reason)
+        #expect(MeetupRefusal.localized("Meetup is full.", bundle: Self.english) == "Meetup is full.")
+    }
+
+    /// The server says "pets" for one as well.
+    @Test func oneFollowedPetIsOnePet() {
+        #expect(MeetupRefusal.localized("Requires at least 1 followed pets.", bundle: Self.english) == "Requires at least 1 followed pet.")
+    }
+
+    @Test func aSentenceItDoesNotKnowIsShownAsTheServerWroteIt() throws {
+        #expect(MeetupRefusal.localized("Something new. Dogs only.", bundle: try Self.chinese(), locale: Self.zh) == "Something new. 仅限狗。")
+    }
+}