import Combine
import Foundation
import GRDB
import Martin

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

    init(_ xmppConnection: XMPPClient) {
        messageProcessor = ArchivedMessageProcessor()

        // subscribe to archived messages
        xmppConnection.module(.mam).archivedMessagesPublisher
            .sink(receiveValue: { [weak self] archived in
                guard let self = self else { return }
                Task {
                    await self.messageProcessor.addMessage(archived)
                }
            })
            .store(in: &cancellables)
    }

    // func requestArchivedMessages(for roster: Roster, before: String? = nil, after: String? = nil, in module: MessageArchiveManagementModule) async {
    //     print(roster, before, after, module)
    //
    //     // let endDate = Date()
    //     // let startDate = Calendar.current.date(byAdding: .day, value: -Const.mamRequestDaysLength, to: endDate) ?? Date()
    //     // let response = try? await module.queryItems(
    //     //     componentJid: JID(credentials.bareJid),
    //     //     with: JID(roster.bareJid),
    //     //     start: startDate,
    //     //     end: endDate,
    //     //     queryId: UUID().uuidString
    //     // )
    //     // let query: RSM.Query = .init(before: nil, after: nil, max: nil)
    // }

    // func requestArchivedMessages(for roster: Roster, before: String? = nil, after: String? = nil) async {
    //     assert(before != nil || after != nil, "Either before or after must be provided")
    //     if !discoManager.features.map({ $0.xep }).contains("XEP-0313") {
    //         return
    //     }
    //     let module = connection.module(MessageArchiveManagementModule.self)
    //     await mamManager.requestArchivedMessages(for: roster, before: before, after: after, in: module)
    // }
}

private actor ArchivedMessageProcessor {
    private var messageBuffer: [Martin.MessageArchiveManagementModule.ArchivedMessageReceived] = []
    private let batchSize = 20

    func addMessage(_ message: Martin.MessageArchiveManagementModule.ArchivedMessageReceived) async {
        messageBuffer.append(message)
        if messageBuffer.count >= batchSize {
            await processBatch()
        }
    }

    private func processBatch() async {
        guard !messageBuffer.isEmpty else { return }

        let batch = messageBuffer.prefix(batchSize)
        messageBuffer.removeFirst(min(batchSize, messageBuffer.count))

        for archived in batch {
            await handleMessage(archived)
        }
    }

    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)")
            }
        }
    }
}

// final class ClientMartinMAM {
//     private var cancellables: Set<AnyCancellable> = []
//
//     init(_ xmppConnection: XMPPClient) {
//         // subscribe to archived messages
//         xmppConnection.module(.mam).archivedMessagesPublisher
//             .sink(receiveValue: { [weak self] archived in
//                 let message = archived.message
//                 message.attribute("archived_date", newValue: "\(archived.timestamp.timeIntervalSince1970)")
//                 self?.handleMessage(archived)
//             })
//             .store(in: &cancellables)
//     }
//
//     private func handleMessage(_ received: Martin.MessageArchiveManagementModule.ArchivedMessageReceived) {
//         let message = received.message
//         let date = received.timestamp
//         #if DEBUG
//             print("---")
//             print("Archive message received: \(message)")
//             print("Date: \(date)")
//             print("---")
//         #endif
//
//         if let msg = Message.map(message) {
//             Task {
//                 do {
//                     var msg = msg
//                     msg.date = received.timestamp
//                     try await msg.save()
//                 } catch {
//                     logIt(.error, "Error saving message: \(error)")
//                 }
//             }
//         }
//     }
// }