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.PlayArrow
import androidx.compose.material.icons.filled.PlaylistAdd
import androidx.compose.material.icons.filled.Refresh
import androidx.compose.material.icons.filled.Search
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.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.collectAsState
import androidx.compose.runtime.getValue
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.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 VideoLibraryScreen(
  viewModel: MainViewModel,
  onPlayVideo: (MediaItemData) -> Unit,
  onAddToPlaylist: (MediaItemData) -> Unit,
  onPickMediaFile: () -> Unit,
  modifier: Modifier = Modifier
) {
  val videoItems by viewModel.videoItems.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()

  var showSortMenu by remember { mutableStateOf(false) }

  Column(
    modifier = modifier
      .fillMaxSize()
      .background(AmoledBlack)
      .statusBarsPadding()
      .testTag("video_library_screen")
  ) {
    // Top Bar
    Row(
      modifier = Modifier
        .fillMaxWidth()
        .padding(horizontal = 16.dp, vertical = 8.dp),
      verticalAlignment = Alignment.CenterVertically,
      horizontalArrangement = Arrangement.SpaceBetween
    ) {
      Text(
        text = "Video Library",
        color = TextPrimary,
        style = MaterialTheme.typography.headlineMedium,
        fontWeight = FontWeight.Bold
      )

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

        Box {
          IconButton(
            onClick = { showSortMenu = true },
            modifier = Modifier.testTag("video_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
                }
              )
            }
          }
        }

        IconButton(
          onClick = { viewModel.scanMedia() },
          modifier = Modifier.testTag("video_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 Library Search Bar at the top
    LibrarySearchBar(
      searchQuery = searchQuery,
      onQueryChange = { viewModel.setSearchQuery(it) },
      matchCount = videoItems.size,
      placeholderText = "Filter videos by title or artist...",
      testTag = "video_search_bar"
    )

    Spacer(modifier = Modifier.height(4.dp))

    if (videoItems.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.Videocam,
            contentDescription = null,
            tint = AccentViolet,
            modifier = Modifier.size(56.dp)
          )
          Spacer(modifier = Modifier.height(14.dp))
          Text(
            text = if (searchQuery.isNotBlank()) {
              "No videos matching \"$searchQuery\" found.\nCheck the video title or artist name."
            } else {
              "No videos discovered on device."
            },
            color = TextSecondary,
            textAlign = androidx.compose.ui.text.style.TextAlign.Center,
            style = MaterialTheme.typography.bodyMedium
          )
          Spacer(modifier = Modifier.height(16.dp))
          if (searchQuery.isNotBlank()) {
            Surface(
              onClick = { viewModel.setSearchQuery("") },
              shape = RoundedCornerShape(10.dp),
              color = SurfaceElevated
            ) {
              Text(
                text = "Clear Search Filter",
                color = AccentViolet,
                fontWeight = FontWeight.Bold,
                modifier = Modifier.padding(horizontal = 16.dp, vertical = 10.dp)
              )
            }
          } else {
            Surface(
              onClick = onPickMediaFile,
              shape = RoundedCornerShape(10.dp),
              color = AccentViolet
            ) {
              Text(
                text = "Open Video File",
                color = Color.Black,
                fontWeight = FontWeight.Bold,
                modifier = Modifier.padding(horizontal = 16.dp, vertical = 10.dp)
              )
            }
          }
        }
      }
    } else if (isGrid) {
      LazyVerticalGrid(
        columns = GridCells.Adaptive(160.dp),
        modifier = Modifier
          .fillMaxSize()
          .padding(horizontal = 12.dp),
        verticalArrangement = Arrangement.spacedBy(12.dp),
        horizontalArrangement = Arrangement.spacedBy(12.dp)
      ) {
        items(videoItems, key = { it.id }) { video ->
          VideoGridItem(
            video = video,
            onClick = { onPlayVideo(video) },
            onAddToPlaylist = { onAddToPlaylist(video) },
            onDetails = { viewModel.showMediaDetails(video) }
          )
        }
      }
    } else {
      LazyColumn(modifier = Modifier.fillMaxSize()) {
        items(videoItems, key = { it.id }) { video ->
          VideoListItem(
            video = video,
            onClick = { onPlayVideo(video) },
            onAddToPlaylist = { onAddToPlaylist(video) },
            onDetails = { viewModel.showMediaDetails(video) }
          )
        }
      }
    }
  }
}

@Composable
fun VideoGridItem(
  video: MediaItemData,
  onClick: () -> Unit,
  onAddToPlaylist: () -> Unit,
  onDetails: () -> Unit
) {
  var showMenu by remember { mutableStateOf(false) }

  Surface(
    modifier = Modifier
      .fillMaxWidth()
      .clip(RoundedCornerShape(12.dp))
      .clickable { onClick() }
      .testTag("video_grid_item_${video.id}"),
    color = SurfaceSecondary
  ) {
    Column {
      Box(
        modifier = Modifier
          .fillMaxWidth()
          .height(110.dp)
          .background(SurfaceElevated),
        contentAlignment = Alignment.Center
      ) {
        if (!video.albumArtUri.isNullOrBlank()) {
          AsyncImage(
            model = Uri.parse(video.albumArtUri),
            contentDescription = null,
            contentScale = ContentScale.Crop,
            modifier = Modifier.fillMaxSize()
          )
        } else {
          Icon(imageVector = Icons.Default.Videocam, contentDescription = null, tint = AccentViolet, modifier = Modifier.size(40.dp))
        }

        // Duration Pill
        Surface(
          shape = RoundedCornerShape(4.dp),
          color = Color.Black.copy(alpha = 0.8f),
          modifier = Modifier
            .align(Alignment.BottomEnd)
            .padding(6.dp)
        ) {
          Text(
            text = video.formattedDuration,
            color = Color.White,
            fontSize = 10.sp,
            fontWeight = FontWeight.Bold,
            modifier = Modifier.padding(horizontal = 5.dp, vertical = 2.dp)
          )
        }

        // Resolution Pill
        if (video.resolutionString.isNotBlank()) {
          Surface(
            shape = RoundedCornerShape(4.dp),
            color = Color.Black.copy(alpha = 0.8f),
            modifier = Modifier
              .align(Alignment.BottomStart)
              .padding(6.dp)
          ) {
            Text(
              text = video.resolutionString,
              color = AccentViolet,
              fontSize = 9.sp,
              fontWeight = FontWeight.Bold,
              modifier = Modifier.padding(horizontal = 4.dp, vertical = 2.dp)
            )
          }
        }
      }

      Column(modifier = Modifier.padding(8.dp)) {
        Row(
          modifier = Modifier.fillMaxWidth(),
          horizontalArrangement = Arrangement.SpaceBetween,
          verticalAlignment = Alignment.CenterVertically
        ) {
          Text(
            text = video.title,
            color = TextPrimary,
            fontSize = 13.sp,
            fontWeight = FontWeight.SemiBold,
            maxLines = 1,
            overflow = TextOverflow.Ellipsis,
            modifier = Modifier.weight(1f)
          )

          Box {
            IconButton(onClick = { showMenu = true }, modifier = Modifier.size(24.dp)) {
              Icon(imageVector = Icons.Default.MoreVert, contentDescription = null, tint = TextSecondary, modifier = Modifier.size(16.dp))
            }
            DropdownMenu(expanded = showMenu, onDismissRequest = { showMenu = false }, modifier = Modifier.background(SurfaceElevated)) {
              DropdownMenuItem(text = { Text("Play in Queue", color = TextPrimary) }, onClick = { PlaybackManager.addToQueue(video); showMenu = false })
              DropdownMenuItem(text = { Text("Add to Playlist", color = TextPrimary) }, onClick = { onAddToPlaylist(); showMenu = false })
              DropdownMenuItem(text = { Text("Details", color = TextPrimary) }, onClick = { onDetails(); showMenu = false })
            }
          }
        }

        Text(
          text = "${video.folderName} • ${video.formattedSize}",
          color = TextSecondary,
          fontSize = 11.sp,
          maxLines = 1,
          overflow = TextOverflow.Ellipsis
        )
      }
    }
  }
}

@Composable
fun VideoListItem(
  video: MediaItemData,
  onClick: () -> Unit,
  onAddToPlaylist: () -> Unit,
  onDetails: () -> Unit
) {
  var showMenu by remember { mutableStateOf(false) }

  Row(
    modifier = Modifier
      .fillMaxWidth()
      .clickable { onClick() }
      .padding(horizontal = 16.dp, vertical = 8.dp)
      .testTag("video_list_item_${video.id}"),
    verticalAlignment = Alignment.CenterVertically
  ) {
    Box(
      modifier = Modifier
        .size(width = 80.dp, height = 52.dp)
        .clip(RoundedCornerShape(8.dp))
        .background(SurfaceElevated),
      contentAlignment = Alignment.Center
    ) {
      if (!video.albumArtUri.isNullOrBlank()) {
        AsyncImage(
          model = Uri.parse(video.albumArtUri),
          contentDescription = null,
          contentScale = ContentScale.Crop,
          modifier = Modifier.fillMaxSize()
        )
      } else {
        Icon(imageVector = Icons.Default.Videocam, contentDescription = null, tint = AccentViolet)
      }

      Surface(
        shape = RoundedCornerShape(3.dp),
        color = Color.Black.copy(alpha = 0.8f),
        modifier = Modifier
          .align(Alignment.BottomEnd)
          .padding(3.dp)
      ) {
        Text(
          text = video.formattedDuration,
          color = Color.White,
          fontSize = 9.sp,
          fontWeight = FontWeight.Bold,
          modifier = Modifier.padding(horizontal = 3.dp, vertical = 1.dp)
        )
      }
    }

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

    Column(modifier = Modifier.weight(1f)) {
      Text(
        text = video.title,
        color = TextPrimary,
        fontSize = 14.sp,
        fontWeight = FontWeight.Medium,
        maxLines = 1,
        overflow = TextOverflow.Ellipsis
      )
      Spacer(modifier = Modifier.height(2.dp))
      Text(
        text = "${video.folderName} • ${if (video.resolutionString.isNotBlank()) "${video.resolutionString} • " else ""}${video.formattedSize}",
        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(video); showMenu = false })
        DropdownMenuItem(text = { Text("Add to Queue", color = TextPrimary) }, onClick = { PlaybackManager.addToQueue(video); showMenu = false })
        DropdownMenuItem(text = { Text("Add to Playlist", color = TextPrimary) }, onClick = { onAddToPlaylist(); showMenu = false })
        DropdownMenuItem(text = { Text("Details", color = TextPrimary) }, onClick = { onDetails(); showMenu = false })
      }
    }
  }
}