package com.lofiradio.ui

import android.content.Context
import android.util.Log
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import com.lofiradio.data.CHANNELS
import com.lofiradio.data.models.Channel
import com.lofiradio.data.models.StreamInfo
import com.lofiradio.network.ServerApi
import com.lofiradio.network.YouTubeExtractor
import com.lofiradio.player.AudioPlayer
import com.lofiradio.util.Preferences
import kotlinx.coroutines.*

class LofiViewModel(
    private val context: Context,
    private val serverApi: ServerApi,
    private val audioPlayer: AudioPlayer
) : ViewModel() {

    private val _channelList = mutableListOf<Channel>()
    private val _channels = androidx.lifecycle.MutableLiveData<List<Channel>>(emptyList())
    val channels: androidx.lifecycle.LiveData<List<Channel>> get() = _channels

    private fun notifyChannelsChanged() {
        _channels.value = _channelList.toList()
    }

    private val _currentChannel = androidx.lifecycle.MutableLiveData<Channel?>(null)
    val currentChannel: androidx.lifecycle.LiveData<Channel?> get() = _currentChannel

    private val _playerState = androidx.lifecycle.MutableLiveData<PlayerState>(PlayerState.IDLE)
    val playerState: androidx.lifecycle.LiveData<PlayerState> get() = _playerState

    private val _isLoading = androidx.lifecycle.MutableLiveData<Boolean>(false)
    val isLoading: androidx.lifecycle.LiveData<Boolean> get() = _isLoading

    private val _error = androidx.lifecycle.MutableLiveData<String?>(null)
    val error: androidx.lifecycle.LiveData<String?> get() = _error

    private val _isDiscovering = androidx.lifecycle.MutableLiveData<Boolean>(false)
    val isDiscovering: androidx.lifecycle.LiveData<Boolean> get() = _isDiscovering

    private var currentTab: Tab = Tab.ALL

    enum class Tab {
        ALL,
        FAVORITES,
        LIVE
    }

    enum class PlayerState {
        IDLE,
        PLAYING,
        PAUSED,
        BUFFERING,
        ERROR,
        ENDED
    }

    init {
        _channelList.addAll(CHANNELS.map { it.copy() })
        notifyChannelsChanged()
        audioPlayer.onStateChanged = { state ->
            when (state) {
                androidx.media3.common.Player.STATE_READY -> {
                    if (audioPlayer.isPlaying) {
                        _playerState.postValue(PlayerState.PLAYING)
                    } else {
                        _playerState.postValue(PlayerState.PAUSED)
                    }
                }
                androidx.media3.common.Player.STATE_BUFFERING -> {
                    _playerState.postValue(PlayerState.BUFFERING)
                }
                androidx.media3.common.Player.STATE_ENDED -> {
                    _playerState.postValue(PlayerState.ENDED)
                    if (Preferences.isAutoAdvance(context)) {
                        playNext()
                    }
                }
                androidx.media3.common.Player.STATE_IDLE -> {
                    _playerState.postValue(PlayerState.IDLE)
                }
            }
            false
        }

        audioPlayer.onError = { message ->
            _error.postValue(message)
            _playerState.postValue(PlayerState.ERROR)
        }
    }

    fun getVisibleChannels(): List<Channel> {
        return when (currentTab) {
            Tab.ALL -> _channelList
            Tab.FAVORITES -> _channelList.filter { Preferences.isFavorite(context, it.id) }
            Tab.LIVE -> _channelList.filter { it.isLive }
        }
    }

    fun setTab(tab: Tab) {
        currentTab = tab
    }

    fun toggleFavorite(channelId: String) {
        Preferences.toggleFavorite(context, channelId)
        val idx = _channelList.indexOfFirst { it.id == channelId }
        if (idx != -1) {
            val fav = Preferences.isFavorite(context, channelId)
            _channelList[idx] = _channelList[idx].copy(isFavorite = fav)
            notifyChannelsChanged()
        }
    }

    fun playChannel(channel: Channel) {
        _error.value = null
        if (channel.videoId.isNullOrBlank()) {
            _error.value = "Channel is not currently live"
            _playerState.value = PlayerState.ERROR
            return
        }

        when (Preferences.getStreamingMode(context)) {
            Preferences.StreamingMode.SERVER -> {
                playViaServer(channel)
            }
            Preferences.StreamingMode.DIRECT -> {
                playViaDirect(channel)
            }
        }
    }

    private fun playViaServer(channel: Channel) {
        _isLoading.value = true
        viewModelScope.launch {
            try {
                val stream = serverApi.getStream(channel.videoId!!)
                if (stream != null) {
                    audioPlayer.play(stream.videoId, stream.url, stream.streamType)
                    _currentChannel.value = channel
                    _playerState.value = PlayerState.PLAYING
                } else {
                    _error.value = "Could not get stream from server"
                    _playerState.value = PlayerState.ERROR
                }
            } catch (e: Exception) {
                Log.e("LofiViewModel", "Server play error", e)
                _error.value = "Server connection failed: ${e.message}"
                _playerState.value = PlayerState.ERROR
            } finally {
                _isLoading.value = false
            }
        }
    }

    private fun playViaDirect(channel: Channel) {
        _isLoading.value = true
        viewModelScope.launch {
            try {
                val stream = withContext(Dispatchers.IO) {
                    YouTubeExtractor.extractAudioStream(channel.videoId!!)
                }
                if (stream != null) {
                    audioPlayer.play(stream.videoId, stream.url, stream.streamType)
                    _currentChannel.value = channel
                    _playerState.value = PlayerState.PLAYING
                } else {
                    _error.value = "Could not extract stream from YouTube"
                    _playerState.value = PlayerState.ERROR
                }
            } catch (e: Exception) {
                Log.e("LofiViewModel", "Direct play error", e)
                _error.value = "Extraction failed: ${e.message}"
                _playerState.value = PlayerState.ERROR
            } finally {
                _isLoading.value = false
            }
        }
    }

    fun playNext() {
        val current = _currentChannel.value ?: return
        val visible = getVisibleChannels()
        val currentIndex = visible.indexOfFirst { it.id == current.id }
        val nextIndex = (currentIndex + 1) % visible.size
        val nextChannel = visible[nextIndex]
        if (nextChannel.isLive) {
            playChannel(nextChannel)
        }
    }

    fun playPrevious() {
        val current = _currentChannel.value ?: return
        val visible = getVisibleChannels()
        val currentIndex = visible.indexOfFirst { it.id == current.id }
        val prevIndex = if (currentIndex == 0) visible.size - 1 else currentIndex - 1
        val prevChannel = visible[prevIndex]
        if (prevChannel.isLive) {
            playChannel(prevChannel)
        }
    }

    fun pausePlayback() {
        audioPlayer.pause()
    }

    fun resumePlayback() {
        audioPlayer.resume()
    }

    fun stopPlayback() {
        audioPlayer.stop()
        _currentChannel.value = null
        _playerState.value = PlayerState.IDLE
    }

    fun setVolume(volume: Float) {
        audioPlayer.setVolume(volume)
    }

    fun retry() {
        _error.value = null
        val channel = _currentChannel.value
        if (channel != null) {
            playChannel(channel)
        }
    }

    fun discoverAllChannels() {
        _isDiscovering.value = true
        viewModelScope.launch {
            val mode = Preferences.getStreamingMode(context)
            val apiKey = Preferences.getYouTubeApiKey(context)
            val updated = mutableListOf<Channel>()

            for (channel in _channelList.toList()) {
                try {
                    val newChannel = when (mode) {
                        Preferences.StreamingMode.SERVER -> {
                            withContext(Dispatchers.IO) {
                                serverApi.checkChannelLive(channel.id)
                            }
                        }.let { live ->
                            channel.copy(
                                isLive = live?.isLive ?: false,
                                videoId = live?.videoId,
                                liveThumbnail = live?.thumbnail
                            )
                        }
                        Preferences.StreamingMode.DIRECT -> {
                            withContext(Dispatchers.IO) {
                                YouTubeExtractor.discoverVideo(channel.id, channel.handle, apiKey)
                            }
                        }.let { stream ->
                            channel.copy(
                                isLive = stream != null,
                                videoId = stream?.videoId
                            )
                        }
                    }
                    updated.add(newChannel)
                } catch (e: Exception) {
                    Log.e("LofiViewModel", "Discovery error for ${channel.name}", e)
                    updated.add(channel)
                }
                delay(500)
            }
            _channelList.clear()
            _channelList.addAll(updated)
            notifyChannelsChanged()
            _isDiscovering.value = false
        }
    }

    fun getStreamingMode(): Preferences.StreamingMode {
        return Preferences.getStreamingMode(context)
    }

    fun releaseAudioPlayer() {
        audioPlayer.release()
    }

    override fun onCleared() {
    }
}