package chats.data.remote.signalr

import android.util.Log
import io.reactivex.rxjava3.core.Single
import com.microsoft.signalr.HubConnection
import com.microsoft.signalr.HubConnectionBuilder
import com.microsoft.signalr.HubConnectionState
import chats.data.remote.dto.ChatDto
import chats.data.remote.dto.MessageDto
import kotlinx.coroutines.flow.*
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import javax.inject.Inject
import javax.inject.Singleton

import kotlinx.coroutines.delay

data class ReadMessagesRequest(
    val chatId: String,
    val lastReadMessageId: String,
    val lastReadSequenceId: Int
)

data class MessagesReadEvent(
    @com.google.gson.annotations.SerializedName("chatId", alternate = ["ChatId"]) val chatId: String? = null,
    @com.google.gson.annotations.SerializedName("userId", alternate = ["UserId"]) val userId: String? = null,
    @com.google.gson.annotations.SerializedName("lastReadSequenceId", alternate = ["LastReadSequenceId"]) val lastReadSequenceId: Int? = null
) {
    val effectiveChatId: String get() = chatId ?: ""
    val effectiveUserId: String get() = userId ?: ""
    val effectiveLastReadSequenceId: Int get() = lastReadSequenceId ?: 0
}

data class ReactionEvent(
    @com.google.gson.annotations.SerializedName("messageId", alternate = ["MessageId"]) val messageId: String? = null,
    @com.google.gson.annotations.SerializedName("chatId", alternate = ["ChatId"]) val chatId: String? = null,
    @com.google.gson.annotations.SerializedName("userId", alternate = ["UserId"]) val userId: String? = null,
    @com.google.gson.annotations.SerializedName("username", alternate = ["Username", "UserName"]) val username: String? = null,
    @com.google.gson.annotations.SerializedName("emoji", alternate = ["Emoji"]) val emoji: String? = null
)

enum class ConnectionStatus { CONNECTED, CONNECTING, DISCONNECTED }

@Singleton
class ChatHubClient @Inject constructor() {
    private var hubConnection: HubConnection? = null
    private val _events = MutableSharedFlow<ChatEvent>(extraBufferCapacity = 1024)
    val events: SharedFlow<ChatEvent> = _events.asSharedFlow()
    
    private val _status = MutableStateFlow(ConnectionStatus.DISCONNECTED)
    val status: StateFlow<ConnectionStatus> = _status.asStateFlow()

    private val scope = CoroutineScope(Dispatchers.IO)
    private var lastBaseUrl: String? = null
    private var lastToken: String? = null

    fun connect(baseUrl: String, accessToken: String) {
        if (hubConnection?.connectionState == HubConnectionState.CONNECTED) return
        
        lastBaseUrl = baseUrl
        lastToken = accessToken
        _status.value = ConnectionStatus.CONNECTING

        hubConnection = HubConnectionBuilder.create("${baseUrl}/hubs/chat")
            .withAccessTokenProvider(Single.just(accessToken))
            .build()

        setupHandlers()

        hubConnection?.onClosed { exception ->
            Log.e("ChatHubClient", "Connection closed. Reconnecting...", exception)
            _status.value = ConnectionStatus.DISCONNECTED
            scope.launch {
                delay(5000)
                connect(baseUrl, accessToken)
            }
        }

        scope.launch {
            try {
                hubConnection?.start()?.blockingAwait()
                _status.value = ConnectionStatus.CONNECTED
                Log.d("ChatHubClient", "SignalR Connected")
            } catch (e: Exception) {
                Log.e("ChatHubClient", "SignalR Connection Error", e)
                _status.value = ConnectionStatus.DISCONNECTED
            }
        }
    }

    private fun setupHandlers() {
        hubConnection?.let { conn ->
            conn.on("new_message", { message: MessageDto ->
                _events.tryEmit(ChatEvent.NewMessage(message))
            }, MessageDto::class.java)

            conn.on("messages_read", { data: MessagesReadEvent ->
                _events.tryEmit(ChatEvent.MessagesRead(
                    data.effectiveChatId, 
                    data.effectiveUserId, 
                    data.effectiveLastReadSequenceId
                ))
            }, MessagesReadEvent::class.java)

            conn.on("user_typing", { data: ReactionEvent ->
                _events.tryEmit(ChatEvent.UserTyping(data.chatId ?: "", data.userId ?: ""))
            }, ReactionEvent::class.java)

            conn.on("user_stopped_typing", { data: ReactionEvent ->
                _events.tryEmit(ChatEvent.UserStoppedTyping(data.chatId ?: "", data.userId ?: ""))
            }, ReactionEvent::class.java)

            conn.on("user_online", { userId: String ->
                _events.tryEmit(ChatEvent.UserOnline(userId))
            }, String::class.java)

            conn.on("new_chat", { chat: ChatDto ->
                _events.tryEmit(ChatEvent.NewChat(chat))
            }, ChatDto::class.java)

            conn.on("reaction_added", { data: ReactionEvent ->
                _events.tryEmit(ChatEvent.ReactionUpdated(
                    data.messageId ?: "", 
                    data.chatId ?: "", 
                    data.userId ?: "", 
                    data.emoji ?: ""
                ))
            }, ReactionEvent::class.java)

            conn.on("reaction_removed", { data: ReactionEvent ->
                _events.tryEmit(ChatEvent.ReactionUpdated(
                    data.messageId ?: "", 
                    data.chatId ?: "", 
                    data.userId ?: "", 
                    "" // empty emoji signals removal
                ))
            }, ReactionEvent::class.java)

            // WebRTC Signaling Handlers
            conn.on("call_incoming", { chatId: String, from: String, offer: String, callType: String ->
                _events.tryEmit(ChatEvent.CallIncoming(chatId, from, offer, callType))
            }, String::class.java, String::class.java, String::class.java, String::class.java)

            conn.on("call_answered", { chatId: String, answer: String ->
                _events.tryEmit(ChatEvent.CallAnswered(chatId, answer))
            }, String::class.java, String::class.java)

            conn.on("ice_candidate", { chatId: String, candidate: String ->
                _events.tryEmit(ChatEvent.IceCandidateReceived(chatId, candidate))
            }, String::class.java, String::class.java)

            conn.on("call_ended", { chatId: String ->
                _events.tryEmit(ChatEvent.CallEnded(chatId))
            }, String::class.java)
        }
    }

    fun disconnect() {
        hubConnection?.stop()
        _status.value = ConnectionStatus.DISCONNECTED
    }

    fun readMessages(request: ReadMessagesRequest) {
        if (hubConnection?.connectionState == HubConnectionState.CONNECTED) {
            hubConnection?.send("read_messages", request)
            Log.d("ChatHubClient", "Sent read_messages for chat: ${request.chatId}")
        }
    }

    fun joinChat(chatId: String) {
        scope.launch {
            // Wait for connection to be established if it's currently connecting
            var attempts = 0
            while (hubConnection?.connectionState != HubConnectionState.CONNECTED && attempts < 10) {
                delay(500)
                attempts++
            }
            
            if (hubConnection?.connectionState == HubConnectionState.CONNECTED) {
                hubConnection?.send("join_chat", chatId)
                Log.d("ChatHubClient", "Joined chat room: $chatId")
            } else {
                Log.e("ChatHubClient", "Failed to join chat room $chatId: Not connected")
            }
        }
    }

    fun sendTypingIndicator(chatId: String) {
        if (hubConnection?.connectionState == HubConnectionState.CONNECTED) {
            hubConnection?.send("typing_start", chatId)
            Log.d("ChatHubClient", "Sent typing indicator for chat: $chatId")
        }
    }

    fun sendUserStoppedTyping(chatId: String) {
        if (hubConnection?.connectionState == HubConnectionState.CONNECTED) {
            hubConnection?.send("typing_stop", chatId)
            Log.d("ChatHubClient", "Sent user stopped typing for chat: $chatId")
        }
    }
}