package com.example.ui.admin

import android.app.NotificationChannel
import android.app.NotificationManager
import android.content.Context
import android.os.Build
import android.widget.Toast
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.PaddingValues
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.lazy.LazyColumn
import androidx.compose.foundation.lazy.LazyRow
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.Campaign
import androidx.compose.material.icons.filled.CheckCircle
import androidx.compose.material.icons.filled.NotificationsActive
import androidx.compose.material.icons.filled.Send
import androidx.compose.material3.Button
import androidx.compose.material3.ButtonDefaults
import androidx.compose.material3.Card
import androidx.compose.material3.CardDefaults
import androidx.compose.material3.HorizontalDivider
import androidx.compose.material3.Icon
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.graphics.Color
import androidx.compose.ui.platform.LocalContext
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.core.app.NotificationCompat
import com.example.R
import com.example.ui.theme.FreshVegGreen
import com.example.ui.theme.LoveRedPrimary
import com.example.ui.theme.TextPrimary
import com.example.ui.theme.TextSecondary
import com.example.viewmodel.AdminViewModel
import java.text.SimpleDateFormat
import java.util.Date
import java.util.Locale

@Composable
fun AdminNotificationScreen(
    adminViewModel: AdminViewModel,
    modifier: Modifier = Modifier
) {
    val context = LocalContext.current
    val notifications by adminViewModel.notifications.collectAsState()

    var titleInput by remember { mutableStateOf("") }
    var bodyInput by remember { mutableStateOf("") }
    var selectedType by remember { mutableStateOf("OFFER") }
    var feedbackMessage by remember { mutableStateOf<String?>(null) }

    val templates = listOf(
        "Festive 50% OFF" to Pair("Weekend Special 50% OFF! 🔥", "Craving biryani? Order delicious meals from Love Zone today and get flat 50% discount with code LOVE50!"),
        "Fresh Biryani Alert" to Pair("Hot Dum Biryani Freshly Prepared! 🍗", "Aromatic Hyderabadi Chicken Dum Biryani is hot and ready in Love Zone kitchen. Order before stock runs out!"),
        "Free Delivery Deal" to Pair("Free Home Delivery Tonight! 🛵", "Enjoy free fast doorstep delivery on all food orders above ₹149 today."),
        "New Menu Added" to Pair("New Delicious Snacks Added to Menu! 🍟", "Check out newly added Crispy Chicken Lollipop, Burgers and Thick Shakes on Love Zone app.")
    )

    fun sendDeviceNotification(title: String, message: String) {
        val channelId = "love_zone_notifications"
        val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val channel = NotificationChannel(
                channelId,
                "Love Zone Alerts",
                NotificationManager.IMPORTANCE_DEFAULT
            )
            notificationManager.createNotificationChannel(channel)
        }

        val builder = NotificationCompat.Builder(context, channelId)
            .setSmallIcon(R.drawable.logo_love_zone)
            .setContentTitle(title)
            .setContentText(message)
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            .setAutoCancel(true)

        try {
            notificationManager.notify((System.currentTimeMillis() % 10000).toInt(), builder.build())
        } catch (_: Exception) {}
    }

    LazyColumn(
        modifier = modifier
            .fillMaxSize()
            .padding(16.dp)
            .padding(bottom = 60.dp),
        verticalArrangement = Arrangement.spacedBy(16.dp)
    ) {
        // Header
        item {
            Card(
                shape = RoundedCornerShape(16.dp),
                colors = CardDefaults.cardColors(containerColor = Color(0xFF1E102E)),
                modifier = Modifier.fillMaxWidth()
            ) {
                Row(
                    modifier = Modifier.padding(16.dp),
                    verticalAlignment = Alignment.CenterVertically
                ) {
                    Box(
                        modifier = Modifier
                            .size(44.dp)
                            .background(LoveRedPrimary, CircleShape),
                        contentAlignment = Alignment.Center
                    ) {
                        Icon(Icons.Default.Campaign, contentDescription = null, tint = Color.White, modifier = Modifier.size(24.dp))
                    }
                    Spacer(modifier = Modifier.width(12.dp))
                    Column {
                        Text(text = "Customer Notification Center", color = Color.White, fontWeight = FontWeight.Bold, fontSize = 16.sp)
                        Text(text = "Broadcast deals, discounts, and order announcements to all customer apps instantly.", color = Color(0xFFD1C4E9), fontSize = 11.sp)
                    }
                }
            }
        }

        // Quick Preset Templates
        item {
            Text(text = "Quick One-Tap Templates:", fontWeight = FontWeight.Bold, fontSize = 13.sp, color = TextPrimary)
            Spacer(modifier = Modifier.height(8.dp))
            LazyRow(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
                items(templates) { (label, data) ->
                    Surface(
                        color = Color.White,
                        shape = RoundedCornerShape(12.dp),
                        border = androidx.compose.foundation.BorderStroke(1.dp, Color(0xFFE2E8F0)),
                        modifier = Modifier.clickable {
                            titleInput = data.first
                            bodyInput = data.second
                        }
                    ) {
                        Text(
                            text = label,
                            fontSize = 12.sp,
                            fontWeight = FontWeight.SemiBold,
                            color = LoveRedPrimary,
                            modifier = Modifier.padding(horizontal = 12.dp, vertical = 8.dp)
                        )
                    }
                }
            }
        }

        // Compose Form Card
        item {
            Card(
                shape = RoundedCornerShape(16.dp),
                colors = CardDefaults.cardColors(containerColor = Color.White),
                elevation = CardDefaults.cardElevation(defaultElevation = 2.dp),
                modifier = Modifier.fillMaxWidth()
            ) {
                Column(
                    modifier = Modifier.padding(16.dp),
                    verticalArrangement = Arrangement.spacedBy(12.dp)
                ) {
                    Text(
                        text = "COMPOSE PUSH NOTIFICATION",
                        fontWeight = FontWeight.Bold,
                        fontSize = 12.sp,
                        color = TextSecondary,
                        letterSpacing = 1.sp
                    )

                    OutlinedTextField(
                        value = titleInput,
                        onValueChange = { titleInput = it },
                        label = { Text("Notification Title") },
                        placeholder = { Text("e.g. Flat 50% OFF Weekend Biryani") },
                        singleLine = true,
                        shape = RoundedCornerShape(10.dp),
                        colors = OutlinedTextFieldDefaults.colors(
                            focusedTextColor = Color(0xFF1E2022),
                            unfocusedTextColor = Color(0xFF1E2022),
                            focusedContainerColor = Color.White,
                            unfocusedContainerColor = Color(0xFFF8FAFC),
                            cursorColor = LoveRedPrimary,
                            focusedBorderColor = LoveRedPrimary,
                            unfocusedBorderColor = Color(0xFFCBD5E1)
                        ),
                        modifier = Modifier.fillMaxWidth().testTag("notif_title_input")
                    )

                    OutlinedTextField(
                        value = bodyInput,
                        onValueChange = { bodyInput = it },
                        label = { Text("Message Body") },
                        placeholder = { Text("Write discount details, promo code or update...") },
                        maxLines = 3,
                        shape = RoundedCornerShape(10.dp),
                        colors = OutlinedTextFieldDefaults.colors(
                            focusedTextColor = Color(0xFF1E2022),
                            unfocusedTextColor = Color(0xFF1E2022),
                            focusedContainerColor = Color.White,
                            unfocusedContainerColor = Color(0xFFF8FAFC),
                            cursorColor = LoveRedPrimary,
                            focusedBorderColor = LoveRedPrimary,
                            unfocusedBorderColor = Color(0xFFCBD5E1)
                        ),
                        modifier = Modifier.fillMaxWidth().testTag("notif_body_input")
                    )

                    Row(
                        modifier = Modifier.fillMaxWidth(),
                        horizontalArrangement = Arrangement.spacedBy(8.dp)
                    ) {
                        listOf("OFFER" to "Special Offer", "ORDER_UPDATE" to "Store Update", "ALERT" to "Urgent Alert").forEach { (type, label) ->
                            Surface(
                                color = if (selectedType == type) LoveRedPrimary else Color(0xFFF1F5F9),
                                shape = RoundedCornerShape(10.dp),
                                modifier = Modifier
                                    .weight(1f)
                                    .clickable { selectedType = type }
                            ) {
                                Text(
                                    text = label,
                                    fontSize = 11.sp,
                                    fontWeight = FontWeight.Bold,
                                    color = if (selectedType == type) Color.White else TextPrimary,
                                    modifier = Modifier.padding(vertical = 8.dp),
                                    textAlign = androidx.compose.ui.text.style.TextAlign.Center
                                )
                            }
                        }
                    }

                    if (feedbackMessage != null) {
                        Text(
                            text = feedbackMessage ?: "",
                            color = FreshVegGreen,
                            fontSize = 12.sp,
                            fontWeight = FontWeight.Bold
                        )
                    }

                    Button(
                        onClick = {
                            if (titleInput.isNotBlank() && bodyInput.isNotBlank()) {
                                adminViewModel.broadcastNotification(titleInput, bodyInput, selectedType)
                                sendDeviceNotification(titleInput, bodyInput)
                                feedbackMessage = "Notification broadcasted to all customers successfully! 🚀"
                                Toast.makeText(context, "Broadcast Sent!", Toast.LENGTH_SHORT).show()
                                titleInput = ""
                                bodyInput = ""
                            }
                        },
                        shape = RoundedCornerShape(10.dp),
                        colors = ButtonDefaults.buttonColors(containerColor = LoveRedPrimary),
                        modifier = Modifier
                            .fillMaxWidth()
                            .height(48.dp)
                            .testTag("send_broadcast_button")
                    ) {
                        Icon(Icons.Default.Send, contentDescription = null, modifier = Modifier.size(18.dp))
                        Spacer(modifier = Modifier.width(8.dp))
                        Text(text = "BROADCAST TO CUSTOMERS", fontWeight = FontWeight.Bold, fontSize = 13.sp)
                    }
                }
            }
        }

        // Notification History Section
        item {
            Text(
                text = "Pushed Notifications History (${notifications.size})",
                fontWeight = FontWeight.Bold,
                fontSize = 14.sp,
                color = TextPrimary
            )
        }

        items(notifications) { notif ->
            val dateStr = SimpleDateFormat("dd MMM, hh:mm a", Locale.getDefault()).format(Date(notif.timestamp))
            Card(
                shape = RoundedCornerShape(12.dp),
                colors = CardDefaults.cardColors(containerColor = Color.White),
                elevation = CardDefaults.cardElevation(defaultElevation = 1.dp),
                modifier = Modifier.fillMaxWidth()
            ) {
                Row(modifier = Modifier.padding(12.dp), verticalAlignment = Alignment.Top) {
                    Box(
                        modifier = Modifier
                            .size(36.dp)
                            .background(Color(0xFFFFF1F2), CircleShape),
                        contentAlignment = Alignment.Center
                    ) {
                        Icon(Icons.Default.NotificationsActive, contentDescription = null, tint = LoveRedPrimary, modifier = Modifier.size(18.dp))
                    }
                    Spacer(modifier = Modifier.width(10.dp))
                    Column(modifier = Modifier.weight(1f)) {
                        Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceBetween) {
                            Text(text = notif.title, fontWeight = FontWeight.Bold, fontSize = 13.sp)
                            Text(text = dateStr, fontSize = 10.sp, color = Color.Gray)
                        }
                        Spacer(modifier = Modifier.height(2.dp))
                        Text(text = notif.message, fontSize = 12.sp, color = TextSecondary)
                    }
                }
            }
        }
    }
}