package com.example.ui.screens

import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.layout.statusBarsPadding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.Favorite
import androidx.compose.material.icons.filled.MusicNote
import androidx.compose.material.icons.filled.PlayArrow
import androidx.compose.material.icons.filled.Shuffle
import androidx.compose.material.icons.filled.Videocam
import androidx.compose.material3.Icon
import androidx.compose.material3.IconButton
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.collectAsState
import androidx.compose.runtime.getValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.platform.testTag
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.media3.common.util.UnstableApi
import com.example.data.model.MediaItemData
import com.example.playback.PlaybackManager
import com.example.ui.theme.AccentViolet
import com.example.ui.theme.AmoledBlack
import com.example.ui.theme.SurfaceElevated
import com.example.ui.theme.TextPrimary
import com.example.ui.theme.TextSecondary
import com.example.ui.viewmodel.MainViewModel

@OptIn(UnstableApi::class)
@Composable
fun FavoritesScreen(
  viewModel: MainViewModel,
  onPlayMedia: (MediaItemData) -> Unit,
  modifier: Modifier = Modifier
) {
  val favorites by viewModel.favorites.collectAsState()
  val allMedia by viewModel.allMedia.collectAsState()

  val favoriteMediaItems = favorites.mapNotNull { fav ->
    allMedia.find { it.id == fav.id || it.contentUri == fav.mediaUri } ?: MediaItemData(
      id = fav.id,
      contentUri = fav.mediaUri,
      title = fav.title,
      artist = fav.artist,
      album = fav.album,
      durationMs = fav.durationMs,
      isVideo = fav.isVideo
    )
  }

  Column(
    modifier = modifier
      .fillMaxSize()
      .background(AmoledBlack)
      .statusBarsPadding()
      .testTag("favorites_screen")
  ) {
    Text(
      text = "Favorites",
      color = TextPrimary,
      style = MaterialTheme.typography.headlineMedium,
      fontWeight = FontWeight.Bold,
      modifier = Modifier.padding(horizontal = 16.dp, vertical = 12.dp)
    )

    if (favoriteMediaItems.isNotEmpty()) {
      Row(
        modifier = Modifier
          .fillMaxWidth()
          .padding(horizontal = 16.dp, vertical = 6.dp),
        horizontalArrangement = Arrangement.spacedBy(12.dp)
      ) {
        Surface(
          onClick = { PlaybackManager.setQueue(favoriteMediaItems, 0, autoPlay = true) },
          shape = RoundedCornerShape(10.dp),
          color = AccentViolet,
          modifier = Modifier.weight(1f)
        ) {
          Row(
            modifier = Modifier.padding(vertical = 10.dp),
            horizontalArrangement = Arrangement.Center,
            verticalAlignment = Alignment.CenterVertically
          ) {
            Icon(imageVector = Icons.Default.PlayArrow, contentDescription = null, tint = AmoledBlack)
            Spacer(modifier = Modifier.width(6.dp))
            Text("Play All (${favoriteMediaItems.size})", color = AmoledBlack, fontWeight = FontWeight.Bold)
          }
        }

        Surface(
          onClick = {
            PlaybackManager.toggleShuffle()
            PlaybackManager.setQueue(favoriteMediaItems.shuffled(), 0, autoPlay = true)
          },
          shape = RoundedCornerShape(10.dp),
          color = SurfaceElevated,
          modifier = Modifier.weight(1f)
        ) {
          Row(
            modifier = Modifier.padding(vertical = 10.dp),
            horizontalArrangement = Arrangement.Center,
            verticalAlignment = Alignment.CenterVertically
          ) {
            Icon(imageVector = Icons.Default.Shuffle, contentDescription = null, tint = AccentViolet)
            Spacer(modifier = Modifier.width(6.dp))
            Text("Shuffle", color = TextPrimary, fontWeight = FontWeight.Bold)
          }
        }
      }
    }

    if (favoriteMediaItems.isEmpty()) {
      Box(modifier = Modifier.fillMaxSize().padding(32.dp), contentAlignment = Alignment.Center) {
        Column(horizontalAlignment = Alignment.CenterHorizontally) {
          Icon(imageVector = Icons.Default.Favorite, contentDescription = null, tint = AccentViolet, modifier = Modifier.size(52.dp))
          Text("No favorites yet.", color = TextSecondary, modifier = Modifier.padding(top = 12.dp))
          Text("Tap the heart icon on any song or video to save here.", color = TextSecondary, fontSize = 12.sp)
        }
      }
    } else {
      LazyColumn(modifier = Modifier.fillMaxSize()) {
        items(favoriteMediaItems, key = { it.id }) { item ->
          Row(
            modifier = Modifier
              .fillMaxWidth()
              .clickable { onPlayMedia(item) }
              .padding(horizontal = 16.dp, vertical = 10.dp),
            verticalAlignment = Alignment.CenterVertically
          ) {
            Icon(
              imageVector = if (item.isVideo) Icons.Default.Videocam else Icons.Default.MusicNote,
              contentDescription = null,
              tint = AccentViolet,
              modifier = Modifier.size(24.dp)
            )
            Spacer(modifier = Modifier.width(14.dp))
            Column(modifier = Modifier.weight(1f)) {
              Text(text = item.title, color = TextPrimary, fontSize = 14.sp, fontWeight = FontWeight.Medium)
              Text(text = "${item.artist} • ${item.formattedDuration}", color = TextSecondary, fontSize = 12.sp)
            }
            IconButton(onClick = { viewModel.toggleFavorite(item) }) {
              Icon(imageVector = Icons.Default.Favorite, contentDescription = "Unfavorite", tint = AccentViolet)
            }
          }
        }
      }
    }
  }
}