package com.vgmlr.jamb

import android.content.Context
import android.content.Intent
import android.provider.DocumentsContract
import android.widget.Toast
import androidx.compose.animation.core.animateFloatAsState
import androidx.compose.animation.core.tween
import androidx.compose.foundation.Canvas
import androidx.compose.foundation.ExperimentalFoundationApi
import androidx.compose.foundation.background
import androidx.compose.foundation.combinedClickable
import androidx.compose.foundation.gestures.detectTapGestures
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.itemsIndexed
import androidx.compose.foundation.lazy.rememberLazyListState
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.automirrored.outlined.Article
import androidx.compose.material.icons.automirrored.outlined.HelpOutline
import androidx.compose.material.icons.automirrored.outlined.OpenInNew
import androidx.compose.material.icons.filled.MoreVert
import androidx.compose.material.icons.outlined.Cached
import androidx.compose.material.icons.outlined.DataArray
import androidx.compose.material.icons.outlined.Folder
import androidx.compose.material.icons.outlined.History
import androidx.compose.material.icons.outlined.Settings
import androidx.compose.material3.DropdownMenu
import androidx.compose.material3.DropdownMenuItem
import androidx.compose.material3.ExperimentalMaterial3Api
import androidx.compose.material3.HorizontalDivider
import androidx.compose.material3.Icon
import androidx.compose.material3.IconButton
import androidx.compose.material3.MenuDefaults
import androidx.compose.material3.Slider
import androidx.compose.material3.SliderDefaults
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableFloatStateOf
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.runtime.withFrameNanos
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.graphics.Brush
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.input.pointer.pointerInput
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.platform.LocalUriHandler
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.text.style.TextOverflow
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.lifecycle.compose.collectAsStateWithLifecycle
import java.util.Locale
import kotlin.math.sin
import kotlinx.coroutines.isActive
import androidx.compose.foundation.layout.offset
import androidx.compose.ui.layout.onGloballyPositioned
import androidx.compose.ui.layout.positionInParent
import androidx.compose.ui.platform.LocalDensity
import androidx.compose.ui.unit.IntOffset
import kotlin.math.roundToInt
import androidx.compose.material.icons.filled.Add
import androidx.compose.material.icons.filled.DeleteSweep
import androidx.compose.material.icons.outlined.Delete
import androidx.compose.material.icons.outlined.EditNote

@OptIn(ExperimentalFoundationApi::class)
@Composable
fun PlayerScreen(vm: JambViewModel) {
    val tracks by vm.tracks.collectAsStateWithLifecycle()
    val folders by vm.folders.collectAsStateWithLifecycle()
    val folder by vm.folder.collectAsStateWithLifecycle()
    val mode by vm.mode.collectAsStateWithLifecycle()
    val repeat by vm.repeat.collectAsStateWithLifecycle()
    val index by vm.currentIndex.collectAsStateWithLifecycle()
    val isPlaying by vm.isPlaying.collectAsStateWithLifecycle()
    val position by vm.position.collectAsStateWithLifecycle()
    val selected by vm.selected.collectAsStateWithLifecycle()
    val playlists by vm.playlists.collectAsStateWithLifecycle()
    val currentPlaylist by vm.currentPlaylist.collectAsStateWithLifecycle()
    val playlistItems by vm.playlistItems.collectAsStateWithLifecycle()

    val listState = rememberLazyListState()
    val uriHandler = LocalUriHandler.current
    val context = LocalContext.current
    val density = LocalDensity.current
    
    var showFolder by remember { mutableStateOf(false) }
    var showMenu by remember { mutableStateOf(false) }
    var showVersion by remember { mutableStateOf(false) }
    var showData by remember { mutableStateOf(false) }
    var showPlaylist by remember { mutableStateOf(false) }
    var showName by remember { mutableStateOf(false) }
    var addMode by remember { mutableStateOf(false) }
    var renameMode by remember { mutableStateOf(false) }
    var showDelete by remember { mutableStateOf(false) }
    
    var openTarget by remember { mutableStateOf<JambTrack?>(null) }
    var surprise by remember { mutableStateOf(false) }
    var barCenterY by remember { mutableFloatStateOf(0f) }

    LaunchedEffect(index, tracks.size) {
        val target = index + 1
        if (target in tracks.indices) listState.animateScrollToItem(target)
    }

    Box(modifier = Modifier.fillMaxSize().background(JambColors.Background)) {
        Column(modifier = Modifier.fillMaxSize()) {

            Row(
                modifier = Modifier
                    .fillMaxWidth()
                    .background(JambColors.Primary)
                    .statusBarsPadding()
                    .height(64.dp)
                    .padding(start = 16.dp, end = 4.dp),
                verticalAlignment = Alignment.CenterVertically
            ) {
                Spacer(Modifier.weight(1f))
                Text("jamb", color = JambColors.Title, fontSize = 18.sp)
                Spacer(Modifier.width(14.dp))
                if (openTarget == null) {
                    IconButton(onClick = { showFolder = true }) {
                        Icon(Icons.Outlined.Folder, "Folder", tint = JambColors.Title)
                    }
                    IconButton(onClick = { addMode = false; showPlaylist = true }) {
                        Icon(Icons.AutoMirrored.Outlined.Article, "Play List", tint = JambColors.Title)
                    }
                    IconButton(onClick = { surprise = !surprise }) {
                        Icon(
                            Icons.AutoMirrored.Outlined.HelpOutline,
                            "Surprise",
                            tint = if (surprise) JambColors.Title
                            else JambColors.Title.copy(alpha = 0.35f)
                        )
                    }
                } else {
                    val inPlaylist = currentPlaylist != null &&
                            openTarget?.let { playlistItems.contains(it.key) } == true
                    IconButton(onClick = { addMode = true; showPlaylist = true }) {
                        Icon(Icons.Filled.Add, "Add to Play List", tint = JambColors.Title)
                    }
                    IconButton(
                        enabled = inPlaylist,
                        onClick = {
                            openTarget?.let { vm.removeFromCurrentPlaylist(it.key) }
                            openTarget = null
                        }
                    ) {
                        Icon(
                            Icons.Filled.DeleteSweep,
                            "Remove from Play List",
                            tint = if (inPlaylist) JambColors.Title
                            else JambColors.Title.copy(alpha = 0.35f)
                        )
                    }
                    IconButton(onClick = {
                        openTarget?.let { openInFileManager(context, it) }
                        openTarget = null
                    }) {
                        Icon(Icons.AutoMirrored.Outlined.OpenInNew, "Open", tint = JambColors.Title)
                    }
                }
                Box {
                    IconButton(onClick = { openTarget = null; showMenu = true }) {
                        Icon(Icons.Filled.MoreVert, "Menu", tint = JambColors.Title)
                    }
                    DropdownMenu(
                        expanded = showMenu,
                        onDismissRequest = { showMenu = false },
                        modifier = Modifier
                            .background(JambColors.MenuBg)
                            .padding(horizontal = 6.dp)
                    ) {
                        val itemColors = MenuDefaults.itemColors(
                            textColor = Color(0xFFEEEEEE),
                            leadingIconColor = Color(0xFFEEEEEE)
                        )
                        if (currentPlaylist != null) {
                            DropdownMenuItem(
                                text = { Text("Delete") },
                                leadingIcon = { Icon(Icons.Outlined.Delete, null) },
                                colors = itemColors,
                                onClick = { showMenu = false; showDelete = true }
                            )
                            DropdownMenuItem(
                                text = { Text("Rename") },
                                leadingIcon = { Icon(Icons.Outlined.EditNote, null) },
                                colors = itemColors,
                                onClick = { showMenu = false; renameMode = true; showName = true }
                            )
                            HorizontalDivider(
                                modifier = Modifier.padding(vertical = 8.dp),
                                color = Color(0xFFFFFFFF).copy(alpha = 0.4f),
                                thickness = 1.dp
                            )
                        }
                        DropdownMenuItem(
                            text = { Text("Scan") },
                            leadingIcon = { Icon(Icons.Outlined.Cached, null) },
                            colors = itemColors,
                            onClick = { showMenu = false; vm.rescan() }
                        )
                        DropdownMenuItem(
                            text = { Text("Data") },
                            leadingIcon = { Icon(Icons.Outlined.DataArray, null) },
                            colors = itemColors,
                            onClick = { showMenu = false; showData = true }
                        )
                        DropdownMenuItem(
                            text = { Text("Settings") },
                            leadingIcon = { Icon(Icons.Outlined.Settings, null) },
                            colors = itemColors,
                            onClick = { 
                                showMenu = false
                                context.startActivity(Intent(context, JambSettings::class.java))
                            }
                        )
                        DropdownMenuItem(
                            text = { Text("Version") },
                            leadingIcon = { Icon(Icons.Outlined.History, null) },
                            colors = itemColors,
                            onClick = { showMenu = false; showVersion = true }
                        )
                    }
                }
            }

            PlayerBox(
                track = selected,
                positionMs = position,
                isPlaying = isPlaying,
                onSeek = { vm.seekTo(it) }
            )

            ControlBar(
                mode = mode,
                repeat = repeat,
                onToggleMode = { vm.toggleMode() },
                onPrev = { vm.prev() },
                onNext = { vm.next() },
                onToggleRepeat = { vm.toggleRepeat() },
                modifier = Modifier.onGloballyPositioned {
                    barCenterY = it.positionInParent().y + it.size.height / 2f
                }
            )

            Box(
                modifier = Modifier
                    .weight(1f)
                    .fillMaxWidth()
                    .pointerInput(Unit) { detectTapGestures { openTarget = null } }
            ) {
                if (tracks.isEmpty()) {
                    Text(
                        "No Audio Found",
                        color = JambColors.Title.copy(alpha = 0.6f),
                        modifier = Modifier.align(Alignment.Center)
                    )
                } else if (surprise) {
                    Column(
                        modifier = Modifier.align(Alignment.Center),
                        horizontalAlignment = Alignment.CenterHorizontally
                    ) {
                        Icon(
                            Icons.AutoMirrored.Outlined.HelpOutline,
                            contentDescription = null,
                            tint = JambColors.Title.copy(alpha = 0.1f),
                            modifier = Modifier.size(300.dp)
                        )
                    }
                } else {
                    LazyColumn(
                        state = listState,
                        modifier = Modifier.fillMaxSize()
                    ) {
                        itemsIndexed(tracks) { i, t ->
                            if (i > 0) HorizontalDivider(
                                thickness = 1.dp,
                                color = JambColors.Rule.copy(alpha = 0.2f)
                            )
                            Row(
                                modifier = Modifier
                                    .fillMaxWidth()
                                    .background(
                                        when {
                                            t == openTarget ->
                                                JambColors.Rule.copy(alpha = 0.12f)
                                            i == index ->
                                                JambColors.Primary.copy(alpha = 0.30f)
                                            else -> Color.Transparent
                                        }
                                    )
                                    .combinedClickable(
                                        onClick = { openTarget = null; vm.onTrackTap(i) },
                                        onLongClick = { openTarget = t }
                                    )
                                    .padding(horizontal = 16.dp, vertical = 14.dp),
                                verticalAlignment = Alignment.CenterVertically
                            ) {
                                Text(
                                    t.displayName.substringBeforeLast('.'),
                                    color = JambColors.Title,
                                    maxLines = 1,
                                    overflow = TextOverflow.Ellipsis,
                                    modifier = Modifier.weight(1f)
                                )
                                Spacer(Modifier.width(12.dp))
                                Text(
                                    formatTime(t.durationMs),
                                    color = JambColors.Dull,
                                    fontSize = 15.sp,
                                    maxLines = 1
                                )
                            }
                        }
                        item {
                            Spacer(Modifier.height(48.dp))
                        }
                    }
                }
            }
        }
        val playButtonHeight = 76.dp
        BigPlayButton(
            isPlaying = isPlaying,
            onClick = { vm.playPause() },
            height = playButtonHeight,
            modifier = Modifier
                .align(Alignment.TopCenter)
                .offset {
                    val half = with(density) { playButtonHeight.toPx() / 2f }
                    IntOffset(0, (barCenterY - half).roundToInt())
                }
        )
    }

    if (showFolder) {
        FolderDialog(
            folders = folders,
            selected = folder,
            onPick = { vm.setFolder(it); showFolder = false },
            onDismiss = { showFolder = false }
        )
    }

    if (showPlaylist) {
        PlaylistDialog(
            playlists = playlists,
            selected = if (addMode) null else currentPlaylist,
            onNew = { showPlaylist = false; showName = true },
            onPick = { name ->
                if (addMode) openTarget?.let { vm.addToPlaylist(name, it.key) }
                else vm.loadPlaylist(name)
                openTarget = null
                showPlaylist = false
                addMode = false
            },
            onDismiss = { showPlaylist = false; addMode = false }
        )
    }

    if (showName) {
        val addFile = if (addMode) openTarget?.key else null
        NameDialog(
            initial = if (renameMode) currentPlaylist ?: "" else "",
            placeholder = if (renameMode) "" else vm.defaultPlaylistName(),
            onConfirm = { name ->
                if (renameMode) vm.renameCurrentPlaylist(name)
                else vm.newPlaylist(name, addFile, load = !addMode)
                openTarget = null
                showName = false
                addMode = false
                renameMode = false
            },
            onDismiss = { showName = false; addMode = false; renameMode = false }
        )
    }

    if (showDelete) {
        ConfirmDialog(
            message = "Delete ${currentPlaylist}?",
            onConfirm = { vm.deleteCurrentPlaylist(); showDelete = false },
            onDismiss = { showDelete = false }
        )
    }

    VersionDialog(showVersion, { showVersion = false }, uriHandler)
    DataDialog(
        show = showData,
        location = currentPlaylist ?: if (folder == JambPrefs.ALL) "All Folders" else folder,
        trackCount = tracks.size,
        totalLength = formatTime(tracks.sumOf { it.durationMs }),
        totalSize = formatSize(tracks.sumOf { it.sizeBytes })
    ) { showData = false }
}

@OptIn(ExperimentalMaterial3Api::class)
@Composable
private fun PlayerBox(track: JambTrack?, positionMs: Long, isPlaying: Boolean, onSeek: (Long) -> Unit) {
    var scrubbing by remember { mutableStateOf(false) }
    var scrubValue by remember { mutableFloatStateOf(0f) }

    val thumbSize = 16.dp

    val dur = track?.durationMs ?: 0L
    val displayPos = if (scrubbing) scrubValue.toLong() else positionMs
    val fraction = if (dur > 0) displayPos.coerceIn(0, dur).toFloat() / dur else 0f

    Column(
        modifier = Modifier
            .fillMaxWidth()
            .background(JambColors.SubPrimary)
            .padding(horizontal = 16.dp, vertical = 12.dp)
    ) {
        Spacer(Modifier.height(6.dp))
        Text(
            track?.displayName?.substringBeforeLast('.') ?: "",
            color = JambColors.Title,
            fontSize = 18.sp,
            maxLines = 1,
            overflow = TextOverflow.Ellipsis,
            textAlign = TextAlign.Center,
            modifier = Modifier.fillMaxWidth()
        )
        Spacer(Modifier.height(6.dp))
        Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
            Text(formatTime(displayPos), color = JambColors.Title, fontSize = 16.sp)
            Slider(
                value = if (dur > 0) displayPos.coerceIn(0, dur).toFloat() else 0f,
                onValueChange = { scrubbing = true; scrubValue = it },
                onValueChangeFinished = { onSeek(scrubValue.toLong()); scrubbing = false },
                valueRange = 0f..(if (dur > 0) dur.toFloat() else 1f),
                enabled = dur > 0,
                colors = SliderDefaults.colors(
                    thumbColor = JambColors.Title,
                    activeTrackColor = JambColors.Title,
                    inactiveTrackColor = JambColors.Title.copy(alpha = 0.3f)
                ),
                thumb = {
                    Box(
                        modifier = Modifier
                            .size(thumbSize)
                            .clip(CircleShape)
                            .background(JambColors.Title)
                    )
                },
                track = {
                    EqSeekTrack(
                        fraction = fraction,
                        isPlaying = isPlaying,
                        modifier = Modifier
                            .fillMaxWidth()
                            .height(24.dp)
                    )
                },
                modifier = Modifier.weight(1f).padding(horizontal = 8.dp)
            )
            Text(formatTime(dur), color = JambColors.Title, fontSize = 16.sp)
        }
    }
}

private fun openInFileManager(context: Context, track: JambTrack) {
    val docId = "primary:" + track.relativePath.trimEnd('/')
    val folderUri = DocumentsContract.buildDocumentUri(
        "com.android.externalstorage.documents", docId
    )
    val intent = Intent(Intent.ACTION_VIEW).apply {
        setDataAndType(folderUri, DocumentsContract.Document.MIME_TYPE_DIR)
        addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
    }
    val launched = runCatching {
        context.startActivity(Intent.createChooser(intent, "Open Folder"))
    }.isSuccess
    if (!launched) {
        Toast.makeText(
            context, "No File Manager Assigned", Toast.LENGTH_SHORT
        ).show()
    }
}

@Composable
private fun EqSeekTrack(
    fraction: Float,
    isPlaying: Boolean,
    modifier: Modifier = Modifier,
    barCount: Int = 40,
    speedFactor: Float = 0.3f // animation speed
) {
    val envelope by animateFloatAsState(
        targetValue = if (isPlaying) 1f else 0f,
        animationSpec = tween(durationMillis = 450),
        label = "eqEnvelope"
    )

    var timeSec by remember { mutableFloatStateOf(0f) }
    LaunchedEffect(isPlaying) {
        var last = 0L
        while (isActive && (isPlaying || envelope > 0.01f)) {
            val now = withFrameNanos { it }
            if (last != 0L) timeSec += (now - last) / 1_000_000_000f * speedFactor
            last = now
        }
    }

    val speeds = remember(barCount) { List(barCount) { 4.5f + (it % 7) * 1.4f } }
    val phases = remember(barCount) { List(barCount) { it * 0.6f } }

    Canvas(modifier = modifier) {
        val gap = (size.width * 0.35f) / barCount
        val barWidth = (size.width - gap * (barCount - 1)) / barCount
        val restH = size.height * 0.18f * 0.75f
        val maxH = size.height * 0.75f
        val activeBars = (fraction.coerceIn(0f, 1f) * barCount).toInt()

        for (i in 0 until barCount) {
            val wave = (sin(timeSec * speeds[i] + phases[i]) + 1f) / 2f
            val active = i < activeBars
            val fullH = restH + (maxH - restH) * wave
            val h = if (active) restH + (fullH - restH) * envelope else restH
            val left = i * (barWidth + gap)
            val top = (size.height - h) / 2f
            if (active) {
                drawRect(
                    brush = Brush.verticalGradient(
                        colors = listOf(JambColors.Title, JambColors.Dull), 
                        startY = top,
                        endY = top + h
                    ),
                    topLeft = Offset(left, top),
                    size = Size(barWidth, h)
                )
            } else {
                drawRect(
                    color = JambColors.Title.copy(alpha = 0.3f),
                    topLeft = Offset(left, top),
                    size = Size(barWidth, h)
                )
            }
        }
    }
}

private fun formatTime(ms: Long): String {
    if (ms <= 0) return "0:00"
    val totalSec = ms / 1000
    val h = totalSec / 3600
    val m = (totalSec % 3600) / 60
    val s = totalSec % 60
    return if (h > 0) String.format(Locale.US, "%d:%02d:%02d", h, m, s)
    else String.format(Locale.US, "%d:%02d", m, s)
}

private fun formatSize(bytes: Long): String {
    if (bytes <= 0) return "0 B"
    val units = arrayOf("B", "KB", "MB", "GB", "TB")
    var value = bytes.toDouble()
    var i = 0
    while (value >= 1024 && i < units.size - 1) {
        value /= 1024
        i++
    }
    return if (i == 0) String.format(Locale.US, "%d %s", bytes, units[i])
    else String.format(Locale.US, "%.1f %s", value, units[i])
}