package com.example.ui.screens

import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.horizontalScroll
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.width
import androidx.compose.foundation.layout.widthIn
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.Done
import androidx.compose.material.icons.filled.DoneAll
import androidx.compose.material.icons.filled.Send
import androidx.compose.material3.Card
import androidx.compose.material3.CardDefaults
import androidx.compose.material3.FilterChip
import androidx.compose.material3.FilterChipDefaults
import androidx.compose.material3.Icon
import androidx.compose.material3.IconButton
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.OutlinedTextField
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
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.platform.testTag
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.lifecycle.compose.collectAsStateWithLifecycle
import com.example.data.local.entity.ConversationMessageEntity
import com.example.ui.theme.EmeraldDark
import com.example.ui.theme.EmeraldLight
import com.example.ui.theme.EmeraldPrimary
import com.example.ui.viewmodel.MarketingViewModel
import java.text.SimpleDateFormat
import java.util.Date
import java.util.Locale

@Composable
fun CustomerInboxScreen(
    viewModel: MarketingViewModel,
    modifier: Modifier = Modifier
) {
    val messages by viewModel.conversations.collectAsStateWithLifecycle()

    val phones = messages.map { it.phone }.distinct()
    var selectedPhone by remember(phones) { mutableStateOf(phones.firstOrNull() ?: "") }

    var replyText by remember { mutableStateOf("") }

    val activeThread = messages.filter { it.phone == selectedPhone }
    val activeCustomer = activeThread.firstOrNull()?.customerName ?: "Customer"

    Column(
        modifier = modifier
            .fillMaxSize()
            .padding(horizontal = 16.dp)
    ) {
        Spacer(modifier = Modifier.height(8.dp))

        // Phone Selector chips
        Text(
            text = "Customer Conversations (${phones.size})",
            fontWeight = FontWeight.Bold,
            fontSize = 15.sp,
            color = MaterialTheme.colorScheme.onSurface
        )
        Spacer(modifier = Modifier.height(6.dp))

        Row(
            modifier = Modifier
                .fillMaxWidth()
                .horizontalScroll(rememberScrollState()),
            horizontalArrangement = Arrangement.spacedBy(6.dp)
        ) {
            phones.forEach { ph ->
                val customerName = messages.firstOrNull { it.phone == ph }?.customerName ?: ph
                FilterChip(
                    selected = selectedPhone == ph,
                    onClick = { selectedPhone = ph },
                    label = { Text("$customerName ($ph)", fontSize = 11.sp) },
                    colors = FilterChipDefaults.filterChipColors(
                        selectedContainerColor = EmeraldPrimary.copy(alpha = 0.15f),
                        selectedLabelColor = EmeraldPrimary
                    )
                )
            }
        }

        Spacer(modifier = Modifier.height(8.dp))

        // Chat Box Canvas
        Card(
            modifier = Modifier
                .fillMaxWidth()
                .weight(1f),
            shape = RoundedCornerShape(16.dp),
            colors = CardDefaults.cardColors(containerColor = Color(0xFFEFEAE2)) // WhatsApp background
        ) {
            Column(modifier = Modifier.fillMaxSize()) {
                // Chat Header
                Row(
                    modifier = Modifier
                        .fillMaxWidth()
                        .background(Color(0xFF075E54))
                        .padding(horizontal = 12.dp, vertical = 8.dp),
                    verticalAlignment = Alignment.CenterVertically
                ) {
                    Box(
                        modifier = Modifier
                            .size(34.dp)
                            .clip(CircleShape)
                            .background(Color.White),
                        contentAlignment = Alignment.Center
                    ) {
                        Text(
                            text = (activeCustomer.take(2)).uppercase(),
                            color = Color(0xFF075E54),
                            fontWeight = FontWeight.Bold,
                            fontSize = 12.sp
                        )
                    }
                    Spacer(modifier = Modifier.width(10.dp))
                    Column {
                        Text(
                            text = activeCustomer,
                            color = Color.White,
                            fontWeight = FontWeight.Bold,
                            fontSize = 13.sp
                        )
                        Text(
                            text = "$selectedPhone • 24hr Customer Service Window Active",
                            color = Color(0xFFD4E7E4),
                            fontSize = 10.sp
                        )
                    }
                }

                // Messages list
                LazyColumn(
                    modifier = Modifier
                        .weight(1f)
                        .padding(12.dp),
                    verticalArrangement = Arrangement.spacedBy(8.dp)
                ) {
                    items(activeThread) { msg ->
                        ChatBubble(message = msg)
                    }
                }

                // Quick reply suggestions
                Row(
                    modifier = Modifier
                        .fillMaxWidth()
                        .background(Color.White)
                        .padding(horizontal = 8.dp, vertical = 4.dp)
                        .horizontalScroll(rememberScrollState()),
                    horizontalArrangement = Arrangement.spacedBy(6.dp)
                ) {
                    QuickChip("Send Quotation PDF") {
                        replyText = "Hi $activeCustomer, here is our dealer quotation PDF: https://sunpower.example.com/quote-2026.pdf"
                    }
                    QuickChip("Confirm Site Visit") {
                        replyText = "Our solar technical engineer has scheduled your site audit for tomorrow at 11 AM."
                    }
                    QuickChip("Dealer Margins") {
                        replyText = "We offer 18% distributor margin on orders above 10 units with net-30 credit."
                    }
                }

                // Reply input bar
                Row(
                    modifier = Modifier
                        .fillMaxWidth()
                        .background(Color.White)
                        .padding(8.dp),
                    verticalAlignment = Alignment.CenterVertically
                ) {
                    OutlinedTextField(
                        value = replyText,
                        onValueChange = { replyText = it },
                        placeholder = { Text("Type WhatsApp response...") },
                        modifier = Modifier
                            .weight(1f)
                            .testTag("chat_reply_input"),
                        shape = RoundedCornerShape(24.dp),
                        singleLine = true
                    )
                    Spacer(modifier = Modifier.width(8.dp))
                    IconButton(
                        onClick = {
                            if (replyText.isNotBlank() && selectedPhone.isNotBlank()) {
                                viewModel.sendSingleReply(selectedPhone, activeCustomer, replyText)
                                replyText = ""
                            }
                        },
                        modifier = Modifier
                            .size(44.dp)
                            .clip(CircleShape)
                            .background(EmeraldPrimary)
                            .testTag("send_reply_button")
                    ) {
                        Icon(Icons.Default.Send, contentDescription = "Send", tint = Color.White)
                    }
                }
            }
        }

        Spacer(modifier = Modifier.height(16.dp))
    }
}

@Composable
fun QuickChip(label: String, onClick: () -> Unit) {
    Surface(
        onClick = onClick,
        shape = RoundedCornerShape(12.dp),
        color = Color(0xFFF1F5F9)
    ) {
        Text(
            text = label,
            fontSize = 11.sp,
            color = Color(0xFF0F172A),
            modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp)
        )
    }
}

@Composable
fun ChatBubble(message: ConversationMessageEntity) {
    val isIncoming = message.isIncoming
    val alignment = if (isIncoming) Alignment.Start else Alignment.End
    val bubbleColor = if (isIncoming) Color.White else Color(0xFFD9FDD3) // WhatsApp outgoing light green

    val timeStr = SimpleDateFormat("hh:mm a", Locale.getDefault()).format(Date(message.timestamp))

    Column(
        modifier = Modifier.fillMaxWidth(),
        horizontalAlignment = alignment
    ) {
        Column(
            modifier = Modifier
                .widthIn(max = 280.dp)
                .clip(
                    RoundedCornerShape(
                        topStart = 12.dp,
                        topEnd = 12.dp,
                        bottomStart = if (isIncoming) 0.dp else 12.dp,
                        bottomEnd = if (isIncoming) 12.dp else 0.dp
                    )
                )
                .background(bubbleColor)
                .padding(10.dp)
        ) {
            if (message.isInteractiveReply) {
                Surface(
                    color = Color(0xFFE0F2FE),
                    shape = RoundedCornerShape(6.dp),
                    modifier = Modifier.padding(bottom = 6.dp)
                ) {
                    Text(
                        text = "Button Clicked: ${message.buttonPayload}",
                        fontSize = 10.sp,
                        fontWeight = FontWeight.Bold,
                        color = Color(0xFF0284C7),
                        modifier = Modifier.padding(horizontal = 6.dp, vertical = 2.dp)
                    )
                }
            }

            Text(
                text = message.messageText,
                fontSize = 13.sp,
                color = Color(0xFF111B21),
                lineHeight = 17.sp
            )

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

            Row(
                modifier = Modifier.align(Alignment.End),
                verticalAlignment = Alignment.CenterVertically
            ) {
                Text(
                    text = timeStr,
                    fontSize = 9.sp,
                    color = Color.Gray
                )
                if (!isIncoming) {
                    Spacer(modifier = Modifier.width(4.dp))
                    Icon(
                        imageVector = if (message.deliveryStatus == "READ") Icons.Default.DoneAll else Icons.Default.Done,
                        contentDescription = null,
                        tint = if (message.deliveryStatus == "READ") Color(0xFF53BDEB) else Color.Gray,
                        modifier = Modifier.size(12.dp)
                    )
                }
            }
        }
    }
}