bitchat-android/app/src/main/java/com/bitchat/android/ui/ChatScreen.kt

package com.bitchat.android.ui

import androidx.compose.animation.*
import androidx.compose.animation.core.*
import androidx.compose.foundation.*
import androidx.compose.foundation.layout.*
import androidx.compose.material3.*
import androidx.compose.runtime.*
import androidx.compose.runtime.livedata.observeAsState
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.Alignment
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.ArrowDownward
import androidx.compose.foundation.BorderStroke
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.material3.IconButton
import androidx.compose.ui.text.TextRange
import androidx.compose.ui.text.input.TextFieldValue
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.zIndex
import com.bitchat.android.model.BitchatMessage

/**
 * Main ChatScreen - REFACTORED to use component-based architecture
 * This is now a coordinator that orchestrates the following UI components:
 * - ChatHeader: App bar, navigation, peer counter
 * - MessageComponents: Message display and formatting
 * - InputComponents: Message input and command suggestions
 * - SidebarComponents: Navigation drawer with channels and people
 * - AboutSheet: App info and password prompts
 * - ChatUIUtils: Utility functions for formatting and colors
 */
@Composable
fun ChatScreen(viewModel: ChatViewModel) {
    val colorScheme = MaterialTheme.colorScheme
    val messages by viewModel.messages.observeAsState(emptyList())
    val connectedPeers by viewModel.connectedPeers.observeAsState(emptyList())
    val nickname by viewModel.nickname.observeAsState("")
    val selectedPrivatePeer by viewModel.selectedPrivateChatPeer.observeAsState()
    val currentChannel by viewModel.currentChannel.observeAsState()
    val joinedChannels by viewModel.joinedChannels.observeAsState(emptySet())
    val hasUnreadChannels by viewModel.unreadChannelMessages.observeAsState(emptyMap())
    val hasUnreadPrivateMessages by viewModel.unreadPrivateMessages.observeAsState(emptySet())
    val privateChats by viewModel.privateChats.observeAsState(emptyMap())
    val channelMessages by viewModel.channelMessages.observeAsState(emptyMap())
    val showSidebar by viewModel.showSidebar.observeAsState(false)
    val showCommandSuggestions by viewModel.showCommandSuggestions.observeAsState(false)
    val commandSuggestions by viewModel.commandSuggestions.observeAsState(emptyList())
    val showMentionSuggestions by viewModel.showMentionSuggestions.observeAsState(false)
    val mentionSuggestions by viewModel.mentionSuggestions.observeAsState(emptyList())
    val showAppInfo by viewModel.showAppInfo.observeAsState(false)

    var messageText by remember { mutableStateOf(TextFieldValue("")) }
    var showPasswordPrompt by remember { mutableStateOf(false) }
    var showPasswordDialog by remember { mutableStateOf(false) }
    var passwordInput by remember { mutableStateOf("") }
    var showLocationChannelsSheet by remember { mutableStateOf(false) }
    var showUserSheet by remember { mutableStateOf(false) }
    var selectedUserForSheet by remember { mutableStateOf("") }
    var selectedMessageForSheet by remember { mutableStateOf<BitchatMessage?>(null) }
    var forceScrollToBottom by remember { mutableStateOf(false) }
    var isScrolledUp by remember { mutableStateOf(false) }

    // Show password dialog when needed
    LaunchedEffect(showPasswordPrompt) {
        showPasswordDialog = showPasswordPrompt
    }

    val isConnected by viewModel.isConnected.observeAsState(false)
    val passwordPromptChannel by viewModel.passwordPromptChannel.observeAsState(null)

    // Determine what messages to show
    val displayMessages = when {
        selectedPrivatePeer != null -> privateChats[selectedPrivatePeer] ?: emptyList()
        currentChannel != null -> channelMessages[currentChannel] ?: emptyList()
        else -> messages
    }

    // Use WindowInsets to handle keyboard properly
    Box(
        modifier = Modifier
            .fillMaxSize()
            .background(colorScheme.background) // Extend background to fill entire screen including status bar
    ) {
        val headerHeight = 42.dp
        
        // Main content area that responds to keyboard/window insets
        Column(
            modifier = Modifier
                .fillMaxSize()
                .windowInsetsPadding(WindowInsets.ime) // This handles keyboard insets
                .windowInsetsPadding(WindowInsets.navigationBars) // Add bottom padding when keyboard is not expanded
        ) {
            // Header spacer - creates exact space for the floating header (status bar + compact header)
            Spacer(
                modifier = Modifier
                    .windowInsetsPadding(WindowInsets.statusBars)
                    .height(headerHeight)
            )

            // Messages area - takes up available space, will compress when keyboard appears
            MessagesList(
                messages = displayMessages,
                currentUserNickname = nickname,
                meshService = viewModel.meshService,
                modifier = Modifier.weight(1f),
                forceScrollToBottom = forceScrollToBottom,
                onScrolledUpChanged = { isUp -> isScrolledUp = isUp },
                onNicknameClick = { fullSenderName ->
                    // Single click - mention user in text input
                    val currentText = messageText.text
                    
                    // Extract base nickname and hash suffix from full sender name
                    val (baseName, hashSuffix) = splitSuffix(fullSenderName)
                    
                    // Check if we're in a geohash channel to include hash suffix
                    val selectedLocationChannel = viewModel.selectedLocationChannel.value
                    val mentionText = if (selectedLocationChannel is com.bitchat.android.geohash.ChannelID.Location && hashSuffix.isNotEmpty()) {
                        // In geohash chat - include the hash suffix from the full display name
                        "@$baseName$hashSuffix"
                    } else {
                        // Regular chat - just the base nickname
                        "@$baseName"
                    }
                    
                    val newText = when {
                        currentText.isEmpty() -> "$mentionText "
                        currentText.endsWith(" ") -> "$currentText$mentionText "
                        else -> "$currentText $mentionText "
                    }
                    
                    messageText = TextFieldValue(
                        text = newText,
                        selection = TextRange(newText.length)
                    )
                },
                onMessageLongPress = { message ->
                    // Message long press - open user action sheet with message context
                    // Extract base nickname from message sender (contains all necessary info)
                    val (baseName, _) = splitSuffix(message.sender)
                    selectedUserForSheet = baseName
                    selectedMessageForSheet = message
                    showUserSheet = true
                }
            )
            // Input area - stays at bottom
            ChatInputSection(
                messageText = messageText,
                onMessageTextChange = { newText: TextFieldValue ->
                    messageText = newText
                    viewModel.updateCommandSuggestions(newText.text)
                    viewModel.updateMentionSuggestions(newText.text)
                },
                onSend = {
                    if (messageText.text.trim().isNotEmpty()) {
                        viewModel.sendMessage(messageText.text.trim())
                        messageText = TextFieldValue("")
                        forceScrollToBottom = !forceScrollToBottom // Toggle to trigger scroll
                    }
                },
                showCommandSuggestions = showCommandSuggestions,
                commandSuggestions = commandSuggestions,
                showMentionSuggestions = showMentionSuggestions,
                mentionSuggestions = mentionSuggestions,
                onCommandSuggestionClick = { suggestion: CommandSuggestion ->
                    val commandText = viewModel.selectCommandSuggestion(suggestion)
                    messageText = TextFieldValue(
                        text = commandText,
                        selection = TextRange(commandText.length)
                    )
                },
                onMentionSuggestionClick = { mention: String ->
                    val mentionText = viewModel.selectMentionSuggestion(mention, messageText.text)
                    messageText = TextFieldValue(
                        text = mentionText,
                        selection = TextRange(mentionText.length)
                    )
                },
                selectedPrivatePeer = selectedPrivatePeer,
                currentChannel = currentChannel,
                nickname = nickname,
                colorScheme = colorScheme
            )
        }

        // Floating header - positioned absolutely at top, ignores keyboard
        ChatFloatingHeader(
            headerHeight = headerHeight,
            selectedPrivatePeer = selectedPrivatePeer,
            currentChannel = currentChannel,
            nickname = nickname,
            viewModel = viewModel,
            colorScheme = colorScheme,
            onSidebarToggle = { viewModel.showSidebar() },
            onShowAppInfo = { viewModel.showAppInfo() },
            onPanicClear = { viewModel.panicClearAllData() },
            onLocationChannelsClick = { showLocationChannelsSheet = true }
        )

        // Divider under header - positioned after status bar + header height
        HorizontalDivider(
            modifier = Modifier
                .fillMaxWidth()
                .windowInsetsPadding(WindowInsets.statusBars)
                .offset(y = headerHeight)
                .zIndex(1f),
            color = colorScheme.outline.copy(alpha = 0.3f)
        )

        val alpha by animateFloatAsState(
            targetValue = if (showSidebar) 0.5f else 0f,
            animationSpec = tween(
                durationMillis = 300,
                easing = EaseOutCubic
            ), label = "overlayAlpha"
        )

        // Only render the background if it's visible
        if (alpha > 0f) {
            Box(
                modifier = Modifier
                    .fillMaxSize()
                    .background(Color.Black.copy(alpha = alpha))
                    .clickable { viewModel.hideSidebar() }
                    .zIndex(1f)
            )
        }

        // Scroll-to-bottom floating button
        AnimatedVisibility(
            visible = isScrolledUp && !showSidebar,
            enter = slideInVertically(initialOffsetY = { it / 2 }) + fadeIn(),
            exit = slideOutVertically(targetOffsetY = { it / 2 }) + fadeOut(),
            modifier = Modifier
                .align(Alignment.BottomEnd)
                .padding(end = 16.dp, bottom = 64.dp)
                .zIndex(1.5f)
                .windowInsetsPadding(WindowInsets.navigationBars)
                .windowInsetsPadding(WindowInsets.ime)
        ) {
            Surface(
                shape = CircleShape,
                color = colorScheme.background,
                tonalElevation = 3.dp,
                shadowElevation = 6.dp,
                border = BorderStroke(2.dp, Color(0xFF00C851))
            ) {
                IconButton(onClick = { forceScrollToBottom = !forceScrollToBottom }) {
                    Icon(
                        imageVector = Icons.Filled.ArrowDownward,
                        contentDescription = "Scroll to bottom",
                        tint = Color(0xFF00C851)
                    )
                }
            }
        }

        AnimatedVisibility(
            visible = showSidebar,
            enter = slideInHorizontally(
                initialOffsetX = { it },
                animationSpec = tween(300, easing = EaseOutCubic)
            ) + fadeIn(animationSpec = tween(300)),
            exit = slideOutHorizontally(
                targetOffsetX = { it },
                animationSpec = tween(250, easing = EaseInCubic)
            ) + fadeOut(animationSpec = tween(250)),
            modifier = Modifier.zIndex(2f)
        ) {
            SidebarOverlay(
                viewModel = viewModel,
                onDismiss = { viewModel.hideSidebar() },
                modifier = Modifier.fillMaxSize()
            )
        }
    }

    // Dialogs and Sheets
    ChatDialogs(
        showPasswordDialog = showPasswordDialog,
        passwordPromptChannel = passwordPromptChannel,
        passwordInput = passwordInput,
        onPasswordChange = { passwordInput = it },
        onPasswordConfirm = {
            if (passwordInput.isNotEmpty()) {
                val success = viewModel.joinChannel(passwordPromptChannel!!, passwordInput)
                if (success) {
                    showPasswordDialog = false
                    passwordInput = ""
                }
            }
        },
        onPasswordDismiss = {
            showPasswordDialog = false
            passwordInput = ""
        },
        showAppInfo = showAppInfo,
        onAppInfoDismiss = { viewModel.hideAppInfo() },
        showLocationChannelsSheet = showLocationChannelsSheet,
        onLocationChannelsSheetDismiss = { showLocationChannelsSheet = false },
        showUserSheet = showUserSheet,
        onUserSheetDismiss = { 
            showUserSheet = false
            selectedMessageForSheet = null // Reset message when dismissing
        },
        selectedUserForSheet = selectedUserForSheet,
        selectedMessageForSheet = selectedMessageForSheet,
        viewModel = viewModel
    )
}

@Composable
private fun ChatInputSection(
    messageText: TextFieldValue,
    onMessageTextChange: (TextFieldValue) -> Unit,
    onSend: () -> Unit,
    showCommandSuggestions: Boolean,
    commandSuggestions: List<CommandSuggestion>,
    showMentionSuggestions: Boolean,
    mentionSuggestions: List<String>,
    onCommandSuggestionClick: (CommandSuggestion) -> Unit,
    onMentionSuggestionClick: (String) -> Unit,
    selectedPrivatePeer: String?,
    currentChannel: String?,
    nickname: String,
    colorScheme: ColorScheme
) {
    Surface(
        modifier = Modifier.fillMaxWidth(),
        color = colorScheme.background
    ) {
        Column {
            HorizontalDivider(color = colorScheme.outline.copy(alpha = 0.3f))
            // Command suggestions box
            if (showCommandSuggestions && commandSuggestions.isNotEmpty()) {
                CommandSuggestionsBox(
                    suggestions = commandSuggestions,
                    onSuggestionClick = onCommandSuggestionClick,
                    modifier = Modifier.fillMaxWidth()
                )

                HorizontalDivider(color = colorScheme.outline.copy(alpha = 0.2f))
            }
            
            // Mention suggestions box
            if (showMentionSuggestions && mentionSuggestions.isNotEmpty()) {
                MentionSuggestionsBox(
                    suggestions = mentionSuggestions,
                    onSuggestionClick = onMentionSuggestionClick,
                    modifier = Modifier.fillMaxWidth()
                )

                HorizontalDivider(color = colorScheme.outline.copy(alpha = 0.2f))
            }

            MessageInput(
                value = messageText,
                onValueChange = onMessageTextChange,
                onSend = onSend,
                selectedPrivatePeer = selectedPrivatePeer,
                currentChannel = currentChannel,
                nickname = nickname,
                modifier = Modifier.fillMaxWidth()
            )
        }
    }
}

@OptIn(ExperimentalMaterial3Api::class)
@Composable
private fun ChatFloatingHeader(
    headerHeight: Dp,
    selectedPrivatePeer: String?,
    currentChannel: String?,
    nickname: String,
    viewModel: ChatViewModel,
    colorScheme: ColorScheme,
    onSidebarToggle: () -> Unit,
    onShowAppInfo: () -> Unit,
    onPanicClear: () -> Unit,
    onLocationChannelsClick: () -> Unit
) {
    Surface(
        modifier = Modifier
            .fillMaxWidth()
            .zIndex(1f)
            .windowInsetsPadding(WindowInsets.statusBars), // Extend into status bar area
        color = colorScheme.background // Solid background color extending into status bar
    ) {
        TopAppBar(
            title = {
                ChatHeaderContent(
                    selectedPrivatePeer = selectedPrivatePeer,
                    currentChannel = currentChannel,
                    nickname = nickname,
                    viewModel = viewModel,
                    onBackClick = {
                        when {
                            selectedPrivatePeer != null -> viewModel.endPrivateChat()
                            currentChannel != null -> viewModel.switchToChannel(null)
                        }
                    },
                    onSidebarClick = onSidebarToggle,
                    onTripleClick = onPanicClear,
                    onShowAppInfo = onShowAppInfo,
                    onLocationChannelsClick = onLocationChannelsClick
                )
            },
            colors = TopAppBarDefaults.topAppBarColors(
                containerColor = Color.Transparent
            ),
            modifier = Modifier.height(headerHeight) // Ensure compact header height
        )
    }
}

@Composable
private fun ChatDialogs(
    showPasswordDialog: Boolean,
    passwordPromptChannel: String?,
    passwordInput: String,
    onPasswordChange: (String) -> Unit,
    onPasswordConfirm: () -> Unit,
    onPasswordDismiss: () -> Unit,
    showAppInfo: Boolean,
    onAppInfoDismiss: () -> Unit,
    showLocationChannelsSheet: Boolean,
    onLocationChannelsSheetDismiss: () -> Unit,
    showUserSheet: Boolean,
    onUserSheetDismiss: () -> Unit,
    selectedUserForSheet: String,
    selectedMessageForSheet: BitchatMessage?,
    viewModel: ChatViewModel
) {
    // Password dialog
    PasswordPromptDialog(
        show = showPasswordDialog,
        channelName = passwordPromptChannel,
        passwordInput = passwordInput,
        onPasswordChange = onPasswordChange,
        onConfirm = onPasswordConfirm,
        onDismiss = onPasswordDismiss
    )

    // About sheet
    AboutSheet(
        isPresented = showAppInfo,
        onDismiss = onAppInfoDismiss
    )
    
    // Location channels sheet
    if (showLocationChannelsSheet) {
        LocationChannelsSheet(
            isPresented = showLocationChannelsSheet,
            onDismiss = onLocationChannelsSheetDismiss,
            viewModel = viewModel
        )
    }
    
    // User action sheet
    if (showUserSheet) {
        ChatUserSheet(
            isPresented = showUserSheet,
            onDismiss = onUserSheetDismiss,
            targetNickname = selectedUserForSheet,
            selectedMessage = selectedMessageForSheet,
            viewModel = viewModel
        )
    }
}