package com.example.ui.customer

import androidx.compose.foundation.background
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.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.CheckCircle
import androidx.compose.material.icons.filled.Discount
import androidx.compose.material.icons.filled.Info
import androidx.compose.material.icons.filled.Notifications
import androidx.compose.material.icons.filled.NotificationsNone
import androidx.compose.material.icons.filled.Refresh
import androidx.compose.material3.Button
import androidx.compose.material3.ButtonDefaults
import androidx.compose.material3.Card
import androidx.compose.material3.CardDefaults
import androidx.compose.material3.Icon
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.runtime.Composable
import androidx.compose.runtime.collectAsState
import androidx.compose.runtime.getValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.platform.testTag
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import com.example.data.model.AppNotification
import com.example.ui.theme.AccentGold
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.CustomerViewModel
import java.text.SimpleDateFormat
import java.util.Date
import java.util.Locale

@Composable
fun AlertsScreen(
    customerViewModel: CustomerViewModel,
    modifier: Modifier = Modifier
) {
    val notifications by customerViewModel.allNotifications.collectAsState()

    Column(
        modifier = modifier
            .fillMaxSize()
            .background(Color(0xFFF8F9FD))
    ) {
        // Top Header
        Surface(
            color = Color.White,
            shadowElevation = 2.dp,
            modifier = Modifier.fillMaxWidth()
        ) {
            Row(
                modifier = Modifier
                    .fillMaxWidth()
                    .padding(horizontal = 16.dp, vertical = 12.dp),
                verticalAlignment = Alignment.CenterVertically,
                horizontalArrangement = Arrangement.SpaceBetween
            ) {
                Text(
                    text = "ALERTS",
                    fontSize = 18.sp,
                    fontWeight = FontWeight.Black,
                    color = TextPrimary
                )

                if (notifications.isNotEmpty()) {
                    TextButton(
                        onClick = { customerViewModel.markNotificationsRead() },
                        modifier = Modifier.testTag("mark_all_read_button")
                    ) {
                        Text(text = "Mark all read", color = LoveRedPrimary, fontSize = 12.sp)
                    }
                }
            }
        }

        if (notifications.isEmpty()) {
            // Empty Alerts state matching video at 00:36
            Box(
                modifier = Modifier
                    .fillMaxSize()
                    .padding(24.dp),
                contentAlignment = Alignment.Center
            ) {
                Column(
                    horizontalAlignment = Alignment.CenterHorizontally,
                    verticalArrangement = Arrangement.Center
                ) {
                    Box(
                        modifier = Modifier
                            .size(110.dp)
                            .background(Color(0xFFF1F5F9), CircleShape),
                        contentAlignment = Alignment.Center
                    ) {
                        Icon(
                            imageVector = Icons.Default.NotificationsNone,
                            contentDescription = "Alerts",
                            tint = Color.Gray,
                            modifier = Modifier.size(54.dp)
                        )
                    }

                    Spacer(modifier = Modifier.height(20.dp))

                    Text(
                        text = "No new alerts",
                        fontSize = 18.sp,
                        fontWeight = FontWeight.Bold,
                        color = TextPrimary
                    )

                    Spacer(modifier = Modifier.height(6.dp))

                    Text(
                        text = "You're all caught up! Order updates, offers, and delivery alerts will appear here.",
                        fontSize = 13.sp,
                        color = TextSecondary,
                        textAlign = TextAlign.Center,
                        modifier = Modifier.padding(horizontal = 24.dp)
                    )

                    Spacer(modifier = Modifier.height(20.dp))

                    Button(
                        onClick = { /* Refresh */ },
                        shape = RoundedCornerShape(10.dp),
                        colors = ButtonDefaults.buttonColors(containerColor = FreshVegGreen)
                    ) {
                        Icon(Icons.Default.Refresh, contentDescription = null, modifier = Modifier.size(16.dp))
                        Spacer(modifier = Modifier.width(6.dp))
                        Text(text = "Check Again", fontWeight = FontWeight.Bold)
                    }
                }
            }
        } else {
            LazyColumn(
                modifier = Modifier
                    .fillMaxSize()
                    .padding(bottom = 80.dp),
                contentPadding = PaddingValues(16.dp),
                verticalArrangement = Arrangement.spacedBy(10.dp)
            ) {
                items(notifications) { notification ->
                    NotificationCard(notification)
                }
            }
        }
    }
}

@Composable
fun NotificationCard(notification: AppNotification) {
    val dateStr = SimpleDateFormat("dd MMM, hh:mm a", Locale.getDefault()).format(Date(notification.timestamp))

    val (icon, iconColor, bgIconColor) = when (notification.type) {
        "OFFER" -> Triple(Icons.Default.Discount, AccentGold, Color(0xFFFFF8E1))
        "ORDER_UPDATE" -> Triple(Icons.Default.CheckCircle, FreshVegGreen, Color(0xFFE8F5E9))
        else -> Triple(Icons.Default.Info, LoveRedPrimary, Color(0xFFFFF1F2))
    }

    Card(
        shape = RoundedCornerShape(14.dp),
        colors = CardDefaults.cardColors(
            containerColor = if (notification.isRead) Color.White else Color(0xFFFFF7ED)
        ),
        elevation = CardDefaults.cardElevation(defaultElevation = 1.dp),
        modifier = Modifier.fillMaxWidth().testTag("alert_item_${notification.id}")
    ) {
        Row(
            modifier = Modifier.padding(14.dp),
            verticalAlignment = Alignment.Top
        ) {
            Box(
                modifier = Modifier
                    .size(40.dp)
                    .background(bgIconColor, CircleShape),
                contentAlignment = Alignment.Center
            ) {
                Icon(imageVector = icon, contentDescription = null, tint = iconColor, modifier = Modifier.size(20.dp))
            }

            Spacer(modifier = Modifier.width(12.dp))

            Column(modifier = Modifier.weight(1f)) {
                Row(
                    modifier = Modifier.fillMaxWidth(),
                    horizontalArrangement = Arrangement.SpaceBetween,
                    verticalAlignment = Alignment.CenterVertically
                ) {
                    Text(
                        text = notification.title,
                        fontWeight = FontWeight.Bold,
                        fontSize = 14.sp,
                        color = TextPrimary,
                        modifier = Modifier.weight(1f)
                    )
                    if (!notification.isRead) {
                        Box(
                            modifier = Modifier
                                .size(8.dp)
                                .background(LoveRedPrimary, CircleShape)
                        )
                    }
                }

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

                Text(
                    text = notification.message,
                    fontSize = 12.sp,
                    color = TextSecondary,
                    lineHeight = 17.sp
                )

                Spacer(modifier = Modifier.height(6.dp))

                Text(
                    text = dateStr,
                    fontSize = 10.sp,
                    color = Color.Gray
                )
            }
        }
    }
}