package com.xuqm.sdk.push

import android.content.Context
import android.util.Log
import com.google.firebase.messaging.FirebaseMessaging
import com.xuqm.sdk.XuqmLoginSession
import com.xuqm.sdk.XuqmSDK
import com.xuqm.sdk.core.ServiceEndpointRegistry
import com.xuqm.sdk.network.ApiClient
import com.xuqm.sdk.push.api.PushApi
import com.xuqm.sdk.push.model.PushRegistrationSnapshot
import com.xuqm.sdk.push.model.PushVendor
import com.xuqm.sdk.push.storage.PushRegistrationStore
import com.xuqm.sdk.utils.DeviceUtils
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.SupervisorJob
import kotlinx.coroutines.launch
import java.util.concurrent.atomic.AtomicReference

object PushSDK {

    private val api: PushApi get() = ApiClient.create(PushApi::class.java, ServiceEndpointRegistry.pushBaseUrl)
    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
    private val registeredUserId = AtomicReference<String?>(null)

    fun currentRegistration(context: Context): PushRegistrationSnapshot? {
        XuqmSDK.requireInit()
        val deviceId = DeviceUtils.getDeviceId(context)
        return store(context).load(deviceId = deviceId, fallbackVendor = detectVendor())
    }

    internal fun updateNativePushToken(
        context: Context,
        vendor: PushVendor,
        pushToken: String,
    ) {
        XuqmSDK.requireInit()
        val normalizedToken = pushToken.trim()
        require(normalizedToken.isNotBlank()) { "pushToken must not be blank" }
        store(context).save(vendor, normalizedToken)
        val sessionUserId = XuqmSDK.currentLoginSession?.userId
        if (sessionUserId != null) {
            bindImUser(context, sessionUserId)
        }
    }

    fun bindImUser(context: Context, userId: String) {
        if (!isReceivePushEnabled(context)) return
        ensureNativePushToken(context)
        registerDevice(context, userId)
    }

    fun unbindImUser(userId: String) {
        unregisterDevice(userId)
    }

    fun setReceivePush(
        context: Context,
        userId: String? = XuqmSDK.currentLoginSession?.userId,
        enabled: Boolean,
    ) {
        XuqmSDK.requireInit()
        store(context).setReceivePush(enabled)
        val resolvedUserId = userId ?: registeredUserId.get()
        if (resolvedUserId != null) {
            scope.launch {
                runCatching {
                    api.setReceivePush(
                        appId = XuqmSDK.appId,
                        userId = resolvedUserId,
                        enabled = enabled,
                    )
                    if (enabled) {
                        bindImUser(context, resolvedUserId)
                    }
                }
            }
        }
    }

    fun registerDevice(
        context: Context,
        userId: String,
    ) {
        XuqmSDK.requireInit()
        val registration = currentRegistration(context)
        val vendor = registration?.vendor ?: detectVendor()
        val pushToken = registration?.pushToken?.takeIf { it.isNotBlank() }
        if (pushToken.isNullOrBlank()) {
            Log.w("XuqmPushSDK", "Native push token not ready yet, waiting for onNewToken()")
            ensureNativePushToken(context)
            return
        }
        scope.launch {
            runCatching {
                api.registerDevice(
                    appId = XuqmSDK.appId,
                    userId = userId,
                    vendor = vendor.name,
                    token = pushToken,
                )
                registeredUserId.set(userId)
                store(context).updateLastUserId(userId)
                Log.i(
                    "XuqmPushSDK",
                    "Registered push device for userId=$userId vendor=${vendor.name}",
                )
            }
        }
    }

    fun unregisterDevice(userId: String) {
        XuqmSDK.requireInit()
        scope.launch {
            runCatching {
                api.unregisterDevice(XuqmSDK.appId, userId)
                registeredUserId.compareAndSet(userId, null)
                store(XuqmSDK.appContext).updateLastUserId(null)
            }
        }
    }

    fun onSdkLogin(session: XuqmLoginSession) {
        val context = runCatching { XuqmSDK.appContext }.getOrNull() ?: return
        if (registeredUserId.get() == session.userId) return
        bindImUser(context, session.userId)
    }

    fun onSdkLogout() {
        val userId = registeredUserId.getAndSet(null) ?: return
        unregisterDevice(userId)
    }

    private fun detectVendor(): PushVendor = PushVendor.FCM

    private fun store(context: Context): PushRegistrationStore =
        PushRegistrationStore(context.applicationContext)

    private fun isReceivePushEnabled(context: Context): Boolean =
        store(context).load(
            deviceId = DeviceUtils.getDeviceId(context),
            fallbackVendor = detectVendor(),
        )?.receivePush ?: true

    private fun ensureNativePushToken(context: Context) {
        val vendor = detectVendor()
        if (vendor != PushVendor.FCM) return
        val registration = currentRegistration(context)
        if (registration?.pushToken?.isNotBlank() == true) return
        runCatching { FirebaseMessaging.getInstance() }
            .onSuccess { messaging ->
                messaging.token
                    .addOnSuccessListener { token ->
                        if (token.isNotBlank()) {
                            store(context).save(PushVendor.FCM, token)
                            val sessionUserId = XuqmSDK.currentLoginSession?.userId
                            if (sessionUserId != null) {
                                registerDevice(context, sessionUserId)
                            }
                        }
                    }
                    .addOnFailureListener { error ->
                        Log.w("XuqmPushSDK", "Unable to fetch FCM token: ${error.message}")
                    }
            }
            .onFailure { error ->
                Log.w("XuqmPushSDK", "Firebase Messaging not available: ${error.message}")
            }
    }
}