import Combine
import Foundation
import GRDB
import Martin

final class ClientMartinMAM {
    private var cancellables: Set<AnyCancellable> = []

    private weak var module: MessageArchiveManagementModule?
    private var afterAvailable = true
    private var beforeAvailable = true

    init(_ xmppConnection: XMPPClient) {
        module = xmppConnection.module(.mam)
        subscribe()
    }

    private func subscribe() {
        // subscribe to archived messages
        module?.archivedMessagesPublisher
            .delay(for: 0.7, scheduler: DispatchQueue.main)
            .sink(receiveValue: { [weak self] archived in
                guard let self = self else { return }
                Task {
                    await self.handleMessage(archived)
                }
            })
            .store(in: &cancellables)
    }

    private func handleMessage(_ received: Martin.MessageArchiveManagementModule.ArchivedMessageReceived) async {
        let message = received.message
        let date = received.timestamp
        #if DEBUG
            print("---")
            print("Archive message received: \(message)")
            print("Date: \(date)")
            print("---")
        #endif

        // Skip archived message if such message already exists in the database
        if let archiveId = message.id {
            try? await Database.shared.dbQueue.read { db in
                if try Message.fetchOne(db, key: archiveId) != nil {
                    return
                }
            }
        }

        if let msg = Message.map(message) {
            do {
                var msg = msg
                msg.date = received.timestamp
                try await msg.save()
            } catch {
                logIt(.error, "Error saving message: \(error)")
            }
        }
    }
}