import Foundation
import Supabase

/// Verwaltet die Echtzeit-Verbindung für "Gerade Jetzt".
/// Neue Posts erscheinen sofort ohne Polling.
@MainActor
class RealtimeService: ObservableObject {
    @Published var newPostsCount = 0

    private var channel: RealtimeChannelV2?
    private var onNewPost: ((Post) -> Void)?

    func startListening(onNewPost: @escaping (Post) -> Void) async {
        self.onNewPost = onNewPost
        guard channel == nil else { return }

        let ch = await supabase.channel("public:posts")

        // Neue Posts in Echtzeit empfangen
        let stream = await ch.postgresChange(
            InsertAction.self,
            schema: "public",
            table:  "posts"
        )

        await ch.subscribe()
        self.channel = ch

        // Stream im Hintergrund konsumieren
        Task { [weak self] in
            for await action in stream {
                await self?.handleInsert(action)
            }
        }
    }

    func stopListening() async {
        if let ch = channel {
            await supabase.removeChannel(ch)
            channel = nil
        }
    }

    private func handleInsert(_ action: InsertAction) {
        // Den neuen Post aus dem Record dekodieren
        guard
            let id        = action.record["id"]?.stringValue,
            let content   = action.record["content"]?.stringValue,
            let createdAt = action.record["created_at"]?.stringValue
                                .flatMap({ ISO8601DateFormatter().date(from: $0) }),
            let userId    = action.record["user_id"]?.stringValue,
            let isAnon    = action.record["is_anonymous"]?.boolValue
        else { return }

        let moodString = action.record["mood"]?.stringValue
        let mood = moodString.flatMap(Mood.init(rawValue:))

        let post = Post(
            id: id,
            author: User.anonymousPlaceholder,  // Profil wird lazily nachgeladen
            content: content,
            mood: mood,
            createdAt: createdAt,
            resonanceCount: 0,
            hasResonated: false,
            commentCount: 0,
            isAnonymous: isAnon,
            nightOf: createdAt
        )

        newPostsCount += 1
        onNewPost?(post)
    }
}

// MARK: - User placeholder für Realtime (Profil wird nachgeladen)

extension User {
    static let anonymousPlaceholder = User(
        id: "anonymous",
        username: "anonym",
        displayName: "anonym",
        bio: nil, avatarURL: nil,
        followerCount: 0, followingCount: 0, postCount: 0, isFollowing: false
    )
}