package com.example.ui.screens

import android.net.Uri
import androidx.annotation.OptIn
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.height
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.grid.GridCells
import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
import androidx.compose.foundation.lazy.grid.items
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.ArrowDownward
import androidx.compose.material.icons.filled.ArrowUpward
import androidx.compose.material.icons.filled.GridView
import androidx.compose.material.icons.filled.MoreVert
import androidx.compose.material.icons.filled.MusicNote
import androidx.compose.material.icons.filled.PlayArrow
import androidx.compose.material.icons.filled.PlaylistAdd
import androidx.compose.material.icons.filled.QueueMusic
import androidx.compose.material.icons.filled.Refresh
import androidx.compose.material.icons.filled.Search
import androidx.compose.material.icons.filled.Shuffle
import androidx.compose.material.icons.filled.Sort
import androidx.compose.material.icons.filled.Videocam
import androidx.compose.material.icons.filled.ViewList
import androidx.compose.material3.CircularProgressIndicator
import androidx.compose.material3.DropdownMenu
import androidx.compose.material3.DropdownMenuItem
import androidx.compose.material3.Icon
import androidx.compose.material3.IconButton
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.OutlinedTextField
import androidx.compose.material3.OutlinedTextFieldDefaults
import androidx.compose.material3.Surface
import androidx.compose.material3.Tab
import androidx.compose.material3.TabRow
import androidx.compose.material3.TabRowDefaults
import androidx.compose.material3.TabRowDefaults.tabIndicatorOffset
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.collectAsState
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableIntStateOf
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.layout.ContentScale
import androidx.compose.ui.platform.testTag
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.style.TextOverflow
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.media3.common.util.UnstableApi
import coil.compose.AsyncImage
import com.example.data.model.MediaItemData
import com.example.data.model.MediaTypeFilter
import com.example.data.model.SortOption
import com.example.data.model.SortOrder
import com.example.playback.PlaybackManager
import com.example.ui.components.LibrarySearchBar
import com.example.ui.theme.AccentViolet
import com.example.ui.theme.AmoledBlack
import com.example.ui.theme.DividerSubtle
import com.example.ui.theme.SurfaceElevated
import com.example.ui.theme.SurfaceSecondary
import com.example.ui.theme.TextPrimary
import com.example.ui.theme.TextSecondary
import com.example.ui.viewmodel.MainViewModel

@OptIn(UnstableApi::class)
@Composable
fun MusicLibraryScreen(
  viewModel: MainViewModel,
  onPlayMedia: (MediaItemData) -> Unit,
  onAddToPlaylist: (MediaItemData) -> Unit,
  onPickMediaFile: () -> Unit,
  modifier: Modifier = Modifier
) {
  val musicItems by viewModel.musicItems.collectAsState()
  val videoItems by viewModel.videoItems.collectAsState()
  val libraryItems by viewModel.libraryItems.collectAsState()
  val libraryFilter by viewModel.libraryFilter.collectAsState()
  val searchQuery by viewModel.searchQuery.collectAsState()
  val isScanning by viewModel.isScanning.collectAsState()
  val isGrid by viewModel.isGridLayout.collectAsState()
  val currentSortOption by viewModel.musicSortOption.collectAsState()
  val currentSortOrder by viewModel.musicSortOrder.collectAsState()

  val activeItems = when (libraryFilter) {
    MediaTypeFilter.ALL -> libraryItems
    MediaTypeFilter.MUSIC -> musicItems
    MediaTypeFilter.VIDEOS -> videoItems
  }

  var selectedTab by remember { mutableIntStateOf(0) }
  val tabs = listOf("Tracks", "Artists", "Albums")
  var showSortMenu by remember { mutableStateOf(false) }

  Column(
    modifier = modifier
      .fillMaxSize()
      .background(AmoledBlack)
      .statusBarsPadding()
      .testTag("music_library_screen")
  ) {
    // Header & Actions
    Row(
      modifier = Modifier
        .fillMaxWidth()
        .padding(horizontal = 16.dp, vertical = 8.dp),
      verticalAlignment = Alignment.CenterVertically,
      horizontalArrangement = Arrangement.SpaceBetween
    ) {
      Text(
        text = if (libraryFilter == MediaTypeFilter.ALL) "Media Library" else if (libraryFilter == MediaTypeFilter.VIDEOS) "Video Library" else "Music Library",
        color = TextPrimary,
        style = MaterialTheme.typography.headlineMedium,
        fontWeight = FontWeight.Bold
      )

      Row(verticalAlignment = Alignment.CenterVertically) {
        // Grid / List Toggle
        IconButton(
          onClick = { viewModel.setIsGridLayout(!isGrid) },
          modifier = Modifier.testTag("music_layout_toggle")
        ) {
          Icon(
            imageVector = if (isGrid) Icons.Default.ViewList else Icons.Default.GridView,
            contentDescription = "Toggle Grid/List",
            tint = TextSecondary
          )
        }

        // Sort Options
        Box {
          IconButton(
            onClick = { showSortMenu = true },
            modifier = Modifier.testTag("music_sort_button")
          ) {
            Icon(
              imageVector = Icons.Default.Sort,
              contentDescription = "Sort",
              tint = AccentViolet
            )
          }

          DropdownMenu(
            expanded = showSortMenu,
            onDismissRequest = { showSortMenu = false },
            modifier = Modifier.background(SurfaceElevated)
          ) {
            SortOption.values().forEach { option ->
              DropdownMenuItem(
                text = {
                  Row(
                    modifier = Modifier.fillMaxWidth(),
                    horizontalArrangement = Arrangement.SpaceBetween,
                    verticalAlignment = Alignment.CenterVertically
                  ) {
                    Text(option.label, color = TextPrimary)
                    if (currentSortOption == option) {
                      Icon(
                        imageVector = if (currentSortOrder == SortOrder.ASCENDING) Icons.Default.ArrowUpward else Icons.Default.ArrowDownward,
                        contentDescription = null,
                        tint = AccentViolet,
                        modifier = Modifier.size(16.dp)
                      )
                    }
                  }
                },
                onClick = {
                  val newOrder = if (currentSortOption == option && currentSortOrder == SortOrder.ASCENDING) {
                    SortOrder.DESCENDING
                  } else {
                    SortOrder.ASCENDING
                  }
                  viewModel.setMusicSort(option, newOrder)
                  showSortMenu = false
                }
              )
            }
          }
        }

        // Rescan Button
        IconButton(
          onClick = { viewModel.scanMedia() },
          modifier = Modifier.testTag("music_rescan_button")
        ) {
          if (isScanning) {
            CircularProgressIndicator(modifier = Modifier.size(20.dp), color = AccentViolet, strokeWidth = 2.dp)
          } else {
            Icon(imageVector = Icons.Default.Refresh, contentDescription = "Rescan", tint = TextSecondary)
          }
        }
      }
    }

    // Prominent Search Bar at the top with live title/artist filtering and type chips
    LibrarySearchBar(
      searchQuery = searchQuery,
      onQueryChange = { viewModel.setSearchQuery(it) },
      selectedFilter = libraryFilter,
      onFilterChange = { viewModel.setLibraryFilter(it) },
      matchCount = activeItems.size,
      placeholderText = "Filter audio & video by title or artist...",
      testTag = "music_search_bar"
    )

    // Category Tabs: only when in MUSIC mode and not in a global search
    if (libraryFilter == MediaTypeFilter.MUSIC) {
      TabRow(
        selectedTabIndex = selectedTab,
        containerColor = AmoledBlack,
        contentColor = AccentViolet,
        indicator = { tabPositions ->
          TabRowDefaults.SecondaryIndicator(
            modifier = Modifier.tabIndicatorOffset(tabPositions[selectedTab]),
            color = AccentViolet
          )
        },
        divider = {
          Box(modifier = Modifier.fillMaxWidth().height(0.5.dp).background(DividerSubtle))
        }
      ) {
        tabs.forEachIndexed { index, title ->
          Tab(
            selected = selectedTab == index,
            onClick = { selectedTab = index },
            text = {
              Text(
                text = title,
                color = if (selectedTab == index) AccentViolet else TextSecondary,
                fontWeight = if (selectedTab == index) FontWeight.Bold else FontWeight.Normal
              )
            }
          )
        }
      }
    }

    // Quick Play All & Shuffle Buttons
    if (activeItems.isNotEmpty() && (libraryFilter != MediaTypeFilter.MUSIC || selectedTab == 0)) {
      Row(
        modifier = Modifier
          .fillMaxWidth()
          .padding(horizontal = 16.dp, vertical = 8.dp),
        horizontalArrangement = Arrangement.spacedBy(12.dp)
      ) {
        Surface(
          onClick = {
            if (activeItems.isNotEmpty()) {
              PlaybackManager.setQueue(activeItems, 0, autoPlay = true)
            }
          },
          shape = RoundedCornerShape(10.dp),
          color = AccentViolet,
          modifier = Modifier
            .weight(1f)
            .testTag("music_play_all_btn")
        ) {
          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 (${activeItems.size})", color = AmoledBlack, fontWeight = FontWeight.Bold, fontSize = 13.sp)
          }
        }

        Surface(
          onClick = {
            if (activeItems.isNotEmpty()) {
              PlaybackManager.toggleShuffle()
              PlaybackManager.setQueue(activeItems.shuffled(), 0, autoPlay = true)
            }
          },
          shape = RoundedCornerShape(10.dp),
          color = SurfaceElevated,
          modifier = Modifier
            .weight(1f)
            .testTag("music_shuffle_all_btn")
        ) {
          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, fontSize = 13.sp)
          }
        }
      }
    }

    // Content based on tab or active media filter
    if (libraryFilter != MediaTypeFilter.MUSIC) {
      TracksTabContent(
        items = activeItems,
        isGrid = isGrid,
        searchQuery = searchQuery,
        onClearSearch = { viewModel.setSearchQuery("") },
        onPlayMedia = onPlayMedia,
        onAddToPlaylist = onAddToPlaylist,
        onDetails = { viewModel.showMediaDetails(it) }
      )
    } else {
      when (selectedTab) {
        0 -> TracksTabContent(
          items = musicItems,
          isGrid = isGrid,
          searchQuery = searchQuery,
          onClearSearch = { viewModel.setSearchQuery("") },
          onPlayMedia = onPlayMedia,
          onAddToPlaylist = onAddToPlaylist,
          onDetails = { viewModel.showMediaDetails(it) }
        )
        1 -> GroupedMediaTabContent(
          groups = musicItems.groupBy { it.artist },
          groupLabel = "Artists",
          onPlayGroup = { items ->
            PlaybackManager.setQueue(items, 0, autoPlay = true)
          }
        )
        2 -> GroupedMediaTabContent(
          groups = musicItems.groupBy { it.album },
          groupLabel = "Albums",
          onPlayGroup = { items ->
            PlaybackManager.setQueue(items, 0, autoPlay = true)
          }
        )
      }
    }
  }
}

@OptIn(UnstableApi::class)
@Composable
private fun TracksTabContent(
  items: List<MediaItemData>,
  isGrid: Boolean,
  searchQuery: String = "",
  onClearSearch: () -> Unit = {},
  onPlayMedia: (MediaItemData) -> Unit,
  onAddToPlaylist: (MediaItemData) -> Unit,
  onDetails: (MediaItemData) -> Unit
) {
  if (items.isEmpty()) {
    Box(
      modifier = Modifier
        .fillMaxSize()
        .padding(32.dp),
      contentAlignment = Alignment.Center
    ) {
      Column(horizontalAlignment = Alignment.CenterHorizontally) {
        Icon(
          imageVector = if (searchQuery.isNotBlank()) Icons.Default.Search else Icons.Default.MusicNote,
          contentDescription = null,
          tint = AccentViolet,
          modifier = Modifier.size(54.dp)
        )
        Spacer(modifier = Modifier.height(14.dp))
        Text(
          text = if (searchQuery.isNotBlank()) {
            "No files matching \"$searchQuery\" found.\nCheck the title or artist spelling."
          } else {
            "No media items found.\nTap Rescan or Open File to add media."
          },
          color = TextSecondary,
          textAlign = androidx.compose.ui.text.style.TextAlign.Center,
          style = MaterialTheme.typography.bodyMedium
        )
        if (searchQuery.isNotBlank()) {
          Spacer(modifier = Modifier.height(16.dp))
          Surface(
            onClick = onClearSearch,
            shape = RoundedCornerShape(10.dp),
            color = SurfaceElevated
          ) {
            Text(
              text = "Clear Search Filter",
              color = AccentViolet,
              fontWeight = FontWeight.Bold,
              modifier = Modifier.padding(horizontal = 16.dp, vertical = 8.dp)
            )
          }
        }
      }
    }
  } else if (isGrid) {
    LazyVerticalGrid(
      columns = GridCells.Adaptive(150.dp),
      modifier = Modifier
        .fillMaxSize()
        .padding(horizontal = 12.dp),
      verticalArrangement = Arrangement.spacedBy(10.dp),
      horizontalArrangement = Arrangement.spacedBy(10.dp)
    ) {
      items(items, key = { it.id }) { item ->
        MusicGridCard(
          item = item,
          onClick = { onPlayMedia(item) },
          onAddToPlaylist = { onAddToPlaylist(item) },
          onDetails = { onDetails(item) }
        )
      }
    }
  } else {
    LazyColumn(modifier = Modifier.fillMaxSize()) {
      items(items, key = { it.id }) { item ->
        MusicListItem(
          item = item,
          onClick = { onPlayMedia(item) },
          onAddToPlaylist = { onAddToPlaylist(item) },
          onDetails = { onDetails(item) }
        )
      }
    }
  }
}

@OptIn(UnstableApi::class)
@Composable
fun MusicListItem(
  item: MediaItemData,
  onClick: () -> Unit,
  onAddToPlaylist: () -> Unit,
  onDetails: () -> Unit,
  modifier: Modifier = Modifier
) {
  var showMenu by remember { mutableStateOf(false) }

  Row(
    modifier = modifier
      .fillMaxWidth()
      .clickable { onClick() }
      .padding(horizontal = 16.dp, vertical = 8.dp),
    verticalAlignment = Alignment.CenterVertically
  ) {
    Box(
      modifier = Modifier
        .size(48.dp)
        .clip(RoundedCornerShape(8.dp))
        .background(SurfaceElevated),
      contentAlignment = Alignment.Center
    ) {
      if (!item.albumArtUri.isNullOrBlank()) {
        AsyncImage(
          model = Uri.parse(item.albumArtUri),
          contentDescription = null,
          contentScale = ContentScale.Crop,
          modifier = Modifier.fillMaxSize()
        )
      } else {
        Icon(
          imageVector = if (item.isVideo) Icons.Default.Videocam else Icons.Default.MusicNote,
          contentDescription = null,
          tint = AccentViolet
        )
      }
    }

    Spacer(modifier = Modifier.width(12.dp))

    Column(modifier = Modifier.weight(1f)) {
      Row(verticalAlignment = Alignment.CenterVertically) {
        if (item.isVideo) {
          Surface(
            shape = RoundedCornerShape(4.dp),
            color = AccentViolet.copy(alpha = 0.2f),
            modifier = Modifier.padding(end = 6.dp)
          ) {
            Text(
              text = "VIDEO",
              color = AccentViolet,
              fontSize = 9.sp,
              fontWeight = FontWeight.Bold,
              modifier = Modifier.padding(horizontal = 4.dp, vertical = 1.dp)
            )
          }
        }
        Text(
          text = item.title,
          color = TextPrimary,
          fontSize = 14.sp,
          fontWeight = FontWeight.Medium,
          maxLines = 1,
          overflow = TextOverflow.Ellipsis
        )
      }
      Spacer(modifier = Modifier.height(2.dp))
      Text(
        text = "${item.artist} • ${item.formattedDuration}",
        color = TextSecondary,
        fontSize = 12.sp,
        maxLines = 1,
        overflow = TextOverflow.Ellipsis
      )
    }

    Box {
      IconButton(onClick = { showMenu = true }) {
        Icon(imageVector = Icons.Default.MoreVert, contentDescription = "Options", tint = TextSecondary)
      }
      DropdownMenu(
        expanded = showMenu,
        onDismissRequest = { showMenu = false },
        modifier = Modifier.background(SurfaceElevated)
      ) {
        DropdownMenuItem(
          text = { Text("Play Next", color = TextPrimary) },
          onClick = {
            PlaybackManager.playNextInQueue(item)
            showMenu = false
          }
        )
        DropdownMenuItem(
          text = { Text("Add to Queue", color = TextPrimary) },
          onClick = {
            PlaybackManager.addToQueue(item)
            showMenu = false
          }
        )
        DropdownMenuItem(
          text = { Text("Add to Playlist", color = TextPrimary) },
          onClick = {
            onAddToPlaylist()
            showMenu = false
          }
        )
        DropdownMenuItem(
          text = { Text("Details", color = TextPrimary) },
          onClick = {
            onDetails()
            showMenu = false
          }
        )
      }
    }
  }
}

@OptIn(UnstableApi::class)
@Composable
fun MusicGridCard(
  item: MediaItemData,
  onClick: () -> Unit,
  onAddToPlaylist: () -> Unit,
  onDetails: () -> Unit
) {
  var showMenu by remember { mutableStateOf(false) }

  Surface(
    modifier = Modifier
      .fillMaxWidth()
      .clip(RoundedCornerShape(12.dp))
      .clickable { onClick() },
    color = SurfaceSecondary
  ) {
    Column(modifier = Modifier.padding(8.dp)) {
      Box(
        modifier = Modifier
          .fillMaxWidth()
          .height(130.dp)
          .clip(RoundedCornerShape(10.dp))
          .background(SurfaceElevated),
        contentAlignment = Alignment.Center
      ) {
        if (!item.albumArtUri.isNullOrBlank()) {
          AsyncImage(
            model = Uri.parse(item.albumArtUri),
            contentDescription = null,
            contentScale = ContentScale.Crop,
            modifier = Modifier.fillMaxSize()
          )
        } else {
          Icon(imageVector = Icons.Default.MusicNote, contentDescription = null, tint = AccentViolet, modifier = Modifier.size(48.dp))
        }

        Box(
          modifier = Modifier
            .align(Alignment.TopEnd)
            .padding(4.dp)
        ) {
          IconButton(onClick = { showMenu = true }, modifier = Modifier.size(32.dp)) {
            Icon(imageVector = Icons.Default.MoreVert, contentDescription = null, tint = TextPrimary)
          }
          DropdownMenu(expanded = showMenu, onDismissRequest = { showMenu = false }, modifier = Modifier.background(SurfaceElevated)) {
            DropdownMenuItem(text = { Text("Add to Queue", color = TextPrimary) }, onClick = { PlaybackManager.addToQueue(item); showMenu = false })
            DropdownMenuItem(text = { Text("Add to Playlist", color = TextPrimary) }, onClick = { onAddToPlaylist(); showMenu = false })
            DropdownMenuItem(text = { Text("Details", color = TextPrimary) }, onClick = { onDetails(); showMenu = false })
          }
        }
      }

      Spacer(modifier = Modifier.height(6.dp))

      Text(
        text = item.title,
        color = TextPrimary,
        fontSize = 13.sp,
        fontWeight = FontWeight.SemiBold,
        maxLines = 1,
        overflow = TextOverflow.Ellipsis
      )
      Text(
        text = item.artist,
        color = TextSecondary,
        fontSize = 11.sp,
        maxLines = 1,
        overflow = TextOverflow.Ellipsis
      )
    }
  }
}

@Composable
private fun GroupedMediaTabContent(
  groups: Map<String, List<MediaItemData>>,
  groupLabel: String,
  onPlayGroup: (List<MediaItemData>) -> Unit
) {
  if (groups.isEmpty()) {
    Box(modifier = Modifier.fillMaxSize().padding(32.dp), contentAlignment = Alignment.Center) {
      Text(text = "No $groupLabel found.", color = TextSecondary)
    }
  } else {
    LazyColumn(modifier = Modifier.fillMaxSize()) {
      groups.forEach { (name, tracks) ->
        item(key = name) {
          Row(
            modifier = Modifier
              .fillMaxWidth()
              .clickable { onPlayGroup(tracks) }
              .padding(horizontal = 16.dp, vertical = 12.dp),
            verticalAlignment = Alignment.CenterVertically
          ) {
            Box(
              modifier = Modifier
                .size(48.dp)
                .clip(RoundedCornerShape(8.dp))
                .background(SurfaceElevated),
              contentAlignment = Alignment.Center
            ) {
              Icon(imageVector = Icons.Default.MusicNote, contentDescription = null, tint = AccentViolet)
            }
            Spacer(modifier = Modifier.width(14.dp))
            Column(modifier = Modifier.weight(1f)) {
              Text(text = name, color = TextPrimary, fontSize = 15.sp, fontWeight = FontWeight.SemiBold)
              Text(text = "${tracks.size} tracks", color = TextSecondary, fontSize = 12.sp)
            }
            IconButton(onClick = { onPlayGroup(tracks) }) {
              Icon(imageVector = Icons.Default.PlayArrow, contentDescription = "Play All", tint = AccentViolet)
            }
          }
        }
      }
    }
  }
}