package com.example.ui.screens

import androidx.compose.foundation.BorderStroke
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.*
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.lazy.rememberLazyListState
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.KeyboardActions
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.automirrored.filled.Send
import androidx.compose.material.icons.filled.Close
import androidx.compose.material.icons.filled.Lock
import androidx.compose.material.icons.filled.VerifiedUser
import androidx.compose.material3.*
import androidx.compose.runtime.*
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.platform.LocalFocusManager
import androidx.compose.ui.platform.testTag
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.input.ImeAction
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.compose.ui.window.Dialog
import androidx.compose.ui.window.DialogProperties
import com.example.data.BookingEntity
import com.example.data.LiveChatEntity
import com.example.ui.PortalViewModel
import com.example.ui.theme.*
import kotlinx.coroutines.delay
import kotlinx.coroutines.launch
import java.text.SimpleDateFormat
import java.util.*

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun Private1vs1ChatDialog(
    booking: BookingEntity,
    viewModel: PortalViewModel,
    senderType: String, // "USER" or "MODEL"
    onDismiss: () -> Unit
) {
    val coroutineScope = rememberCoroutineScope()
    val focusManager = LocalFocusManager.current
    
    // Fetch private chats flow
    val chats by viewModel.getPrivateChats(booking.id).collectAsState(initial = emptyList())
    var textInput by remember { mutableStateOf("") }
    val listState = rememberLazyListState()

    val interlocutorName = if (senderType == "USER") booking.modelName else booking.userName
    val senderId = if (senderType == "USER") booking.userId else "model_${booking.modelId}"
    val senderName = if (senderType == "USER") booking.userName else booking.modelName

    // Auto-scroll on new messages
    LaunchedEffect(chats.size) {
        if (chats.isNotEmpty()) {
            listState.animateScrollToItem(chats.size - 1)
        }
    }

    Dialog(
        onDismissRequest = onDismiss,
        properties = DialogProperties(
            usePlatformDefaultWidth = false
        )
    ) {
        Card(
            shape = RoundedCornerShape(16.dp),
            colors = CardDefaults.cardColors(containerColor = Obsidian),
            modifier = Modifier
                .fillMaxWidth(0.95f)
                .fillMaxHeight(0.85f),
            border = BorderStroke(1.dp, BrandGold.copy(0.2f))
        ) {
            Column(modifier = Modifier.fillMaxSize()) {
                // Header Bar
                Surface(
                    color = DarkGreyGlassElevated,
                    modifier = Modifier.fillMaxWidth()
                ) {
                    Row(
                        modifier = Modifier
                            .fillMaxWidth()
                            .padding(14.dp),
                        verticalAlignment = Alignment.CenterVertically,
                        horizontalArrangement = Arrangement.SpaceBetween
                    ) {
                        Row(verticalAlignment = Alignment.CenterVertically) {
                            // Avatar Circle
                            Box(
                                modifier = Modifier
                                    .size(40.dp)
                                    .clip(CircleShape)
                                    .background(BrandGold),
                                contentAlignment = Alignment.Center
                            ) {
                                Text(
                                    text = interlocutorName.take(1).uppercase(),
                                    color = Color.White,
                                    fontWeight = FontWeight.Bold,
                                    fontSize = 18.sp
                                )
                            }
                            Spacer(modifier = Modifier.width(12.dp))
                            Column {
                                Text(
                                    text = interlocutorName,
                                    style = MaterialTheme.typography.titleMedium,
                                    color = TextPrimary,
                                    fontWeight = FontWeight.Bold
                                )
                                Row(verticalAlignment = Alignment.CenterVertically) {
                                    Icon(
                                        imageVector = Icons.Default.VerifiedUser,
                                        contentDescription = null,
                                        tint = CyanAccent,
                                        modifier = Modifier.size(12.dp)
                                    )
                                    Spacer(modifier = Modifier.width(4.dp))
                                    Text(
                                        text = "Secure Escrow Chat • Contract #${booking.id}",
                                        style = MaterialTheme.typography.labelSmall,
                                        color = TextSecondary
                                    )
                                }
                            }
                        }
                        
                        IconButton(
                            onClick = onDismiss,
                            modifier = Modifier.testTag("private_chat_dismiss_btn")
                        ) {
                            Icon(
                                imageVector = Icons.Default.Close,
                                contentDescription = "Close Chat",
                                tint = TextSecondary
                            )
                        }
                    }
                }

                // Security Notice Banner
                Surface(
                    color = LightGold,
                    modifier = Modifier.fillMaxWidth()
                ) {
                    Row(
                        modifier = Modifier.padding(horizontal = 14.dp, vertical = 6.dp),
                        verticalAlignment = Alignment.CenterVertically,
                        horizontalArrangement = Arrangement.Center
                    ) {
                        Icon(
                            imageVector = Icons.Default.Lock,
                            contentDescription = null,
                            tint = BrandGold,
                            modifier = Modifier.size(12.dp)
                        )
                        Spacer(modifier = Modifier.width(6.dp))
                        Text(
                            text = "Escrow locked chats are encrypted & verified for professional workplace security.",
                            fontSize = 11.sp,
                            color = BrandGold,
                            fontWeight = FontWeight.Medium
                        )
                    }
                }

                // Chat Messages List
                Box(
                    modifier = Modifier
                        .weight(1f)
                        .fillMaxWidth()
                        .background(Color.White)
                        .padding(horizontal = 14.dp)
                ) {
                    if (chats.isEmpty()) {
                        Column(
                            modifier = Modifier.align(Alignment.Center),
                            horizontalAlignment = Alignment.CenterHorizontally
                        ) {
                            Text(
                                text = "💬 Start 1-on-1 Contract Chat",
                                style = MaterialTheme.typography.titleSmall,
                                color = TextSecondary,
                                fontWeight = FontWeight.Bold
                            )
                            Spacer(modifier = Modifier.height(4.dp))
                            Text(
                                text = "Perfect! Coordinate meeting schedules & session details securely.",
                                style = MaterialTheme.typography.bodySmall,
                                color = TextSecondary
                            )
                        }
                    } else {
                        LazyColumn(
                            state = listState,
                            modifier = Modifier.fillMaxSize(),
                            contentPadding = PaddingValues(vertical = 12.dp),
                            verticalArrangement = Arrangement.spacedBy(8.dp)
                        ) {
                            items(chats) { chat ->
                                val isMe = chat.senderId == senderId
                                val alignment = if (isMe) Alignment.End else Alignment.Start
                                val bubbleBg = if (isMe) BrandGold else DarkGreyGlassElevated
                                val textColor = if (isMe) Color.White else TextPrimary
                                val bubbleShape = if (isMe) {
                                    RoundedCornerShape(12.dp, 12.dp, 0.dp, 12.dp)
                                } else {
                                    RoundedCornerShape(12.dp, 12.dp, 12.dp, 0.dp)
                                }

                                Column(
                                    modifier = Modifier.fillMaxWidth(),
                                    horizontalAlignment = alignment
                                ) {
                                    Surface(
                                        color = bubbleBg,
                                        shape = bubbleShape,
                                        border = if (isMe) null else BorderStroke(1.dp, Color.LightGray.copy(0.2f))
                                    ) {
                                        Column(modifier = Modifier.padding(horizontal = 12.dp, vertical = 8.dp)) {
                                            Text(
                                                text = chat.message,
                                                color = textColor,
                                                style = MaterialTheme.typography.bodyMedium
                                            )
                                        }
                                    }
                                    Spacer(modifier = Modifier.height(2.dp))
                                    Text(
                                        text = formatTime(chat.timestamp),
                                        style = MaterialTheme.typography.labelSmall,
                                        color = TextSecondary,
                                        modifier = Modifier.padding(horizontal = 4.dp)
                                    )
                                }
                            }
                        }
                    }
                }

                // Chat Input Panel
                Surface(
                    color = DarkGreyGlassElevated,
                    modifier = Modifier.fillMaxWidth()
                ) {
                    Row(
                        modifier = Modifier
                            .fillMaxWidth()
                            .padding(10.dp),
                        verticalAlignment = Alignment.CenterVertically
                    ) {
                        TextField(
                            value = textInput,
                            onValueChange = { textInput = it },
                            placeholder = { Text("Write secured message...", fontSize = 14.sp) },
                            modifier = Modifier
                                .weight(1f)
                                .testTag("private_msg_input"),
                            colors = TextFieldDefaults.colors(
                                focusedContainerColor = Color.White,
                                unfocusedContainerColor = Color.White,
                                focusedIndicatorColor = Color.Transparent,
                                unfocusedIndicatorColor = Color.Transparent
                            ),
                            shape = RoundedCornerShape(20.dp),
                            singleLine = true,
                            keyboardOptions = KeyboardOptions(imeAction = ImeAction.Send),
                            keyboardActions = KeyboardActions(onSend = {
                                if (textInput.isNotBlank()) {
                                    val msg = textInput
                                    viewModel.sendPrivateMessage(
                                        bookingId = booking.id,
                                        senderId = senderId,
                                        senderName = senderName,
                                        senderType = senderType,
                                        message = msg
                                    )
                                    textInput = ""
                                    focusManager.clearFocus()
                                    
                                    // Simulated Auto-Reply logic for reactive feel
                                    coroutineScope.launch {
                                        delay(1500)
                                        val reply = generateAutoReply(senderType, msg, booking)
                                        viewModel.sendPrivateMessage(
                                            bookingId = booking.id,
                                            senderId = if (senderType == "USER") "model_${booking.modelId}" else booking.userId,
                                            senderName = if (senderType == "USER") booking.modelName else booking.userName,
                                            senderType = if (senderType == "USER") "MODEL" else "USER",
                                            message = reply
                                        )
                                    }
                                }
                            })
                        )
                        Spacer(modifier = Modifier.width(8.dp))
                        IconButton(
                            onClick = {
                                if (textInput.isNotBlank()) {
                                    val msg = textInput
                                    viewModel.sendPrivateMessage(
                                        bookingId = booking.id,
                                        senderId = senderId,
                                        senderName = senderName,
                                        senderType = senderType,
                                        message = msg
                                    )
                                    textInput = ""
                                    focusManager.clearFocus()

                                    // Simulated Auto-Reply logic for reactive feel
                                    coroutineScope.launch {
                                        delay(1500)
                                        val reply = generateAutoReply(senderType, msg, booking)
                                        viewModel.sendPrivateMessage(
                                            bookingId = booking.id,
                                            senderId = if (senderType == "USER") "model_${booking.modelId}" else booking.userId,
                                            senderName = if (senderType == "USER") booking.modelName else booking.userName,
                                            senderType = if (senderType == "USER") "MODEL" else "USER",
                                            message = reply
                                        )
                                    }
                                }
                            },
                            modifier = Modifier
                                .clip(CircleShape)
                                .background(BrandGold)
                                .size(40.dp)
                                .testTag("private_msg_send_btn")
                        ) {
                            Icon(
                                imageVector = Icons.AutoMirrored.Filled.Send,
                                contentDescription = "Send",
                                tint = Color.White,
                                modifier = Modifier.size(18.dp)
                            )
                        }
                    }
                }
            }
        }
    }
}

private fun formatTime(timestamp: Long): String {
    val sdf = SimpleDateFormat("hh:mm a", Locale.getDefault())
    return sdf.format(Date(timestamp))
}

private fun generateAutoReply(myRole: String, msgEntered: String, booking: BookingEntity): String {
    val lowercaseMsg = msgEntered.lowercase()
    if (myRole == "USER") {
        // Model responds to user
        return when {
            lowercaseMsg.contains("hello") || lowercaseMsg.contains("hi") || lowercaseMsg.contains("hey") -> {
                "Hey! Super excited for our shoot. 📸 Everything is ready on my side. Let's make it an amazing session!"
            }
            lowercaseMsg.contains("where") || lowercaseMsg.contains("address") || lowercaseMsg.contains("location") || lowercaseMsg.contains("venue") -> {
                "The venue at '${booking.location}' is perfect for the concept. I'll reach there safely on time."
            }
            lowercaseMsg.contains("time") || lowercaseMsg.contains("schedule") || lowercaseMsg.contains("when") || lowercaseMsg.contains("date") -> {
                "Yes! Confirmed for ${booking.dateString} at ${booking.bookingTime}. See you then!"
            }
            lowercaseMsg.contains("rate") || lowercaseMsg.contains("price") || lowercaseMsg.contains("money") || lowercaseMsg.contains("pay") -> {
                "Perfect! The secure escrow amount of ৳${String.format(Locale.US, "%,.0f", booking.totalPrice)} is locked and safe. No other fee is needed."
            }
            lowercaseMsg.contains("ok") || lowercaseMsg.contains("yes") || lowercaseMsg.contains("perfect") || lowercaseMsg.contains("cool") -> {
                "Sweet! Text me anytime here if you have safehouse guidelines or references."
            }
            else -> {
                "Received! I'm coordinating my travel schedule right now. I'll message you here as soon as I head out. 🚀"
            }
        }
    } else {
        // User responds to model
        return when {
            lowercaseMsg.contains("hello") || lowercaseMsg.contains("hi") || lowercaseMsg.contains("hey") -> {
                "Hello! Yes, checking in. Glad we're locked for the job."
            }
            else -> {
                "Perfect, thanks for keeping in touch! Looking forward to the coordination of model dispatch."
            }
        }
    }
}