package com.example.ui.admin

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.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.Call
import androidx.compose.material.icons.filled.Check
import androidx.compose.material.icons.filled.Close
import androidx.compose.material.icons.filled.DeliveryDining
import androidx.compose.material.icons.filled.LocationOn
import androidx.compose.material.icons.filled.Person
import androidx.compose.material.icons.filled.Restaurant
import androidx.compose.material3.AlertDialog
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.OutlinedButton
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.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.testTag
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import com.example.data.model.DeliveryRider
import com.example.data.model.Order
import com.example.data.model.OrderStatus
import com.example.data.model.RiderStatus
import com.example.ui.components.VegNonVegBadge
import com.example.ui.customer.OrderStatusBadge
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 AdminOrdersScreen(
    adminViewModel: AdminViewModel,
    modifier: Modifier = Modifier
) {
    val orders by adminViewModel.orders.collectAsState()
    val riders by adminViewModel.allRiders.collectAsState()
    var filterStatus by remember { mutableStateOf<String>("ALL") }
    var orderToAssignRider by remember { mutableStateOf<Order?>(null) }

    val filteredOrders = orders.filter {
        when (filterStatus) {
            "ACTIVE" -> it.orderStatus != OrderStatus.DELIVERED && it.orderStatus != OrderStatus.CANCELLED
            "DELIVERED" -> it.orderStatus == OrderStatus.DELIVERED
            else -> true
        }
    }

    Column(
        modifier = modifier
            .fillMaxSize()
            .padding(horizontal = 16.dp, vertical = 8.dp)
    ) {
        // Filter tabs
        Row(
            modifier = Modifier.fillMaxWidth(),
            horizontalArrangement = Arrangement.spacedBy(8.dp)
        ) {
            listOf("ALL" to "All (${orders.size})", "ACTIVE" to "Active (${orders.count { it.orderStatus != OrderStatus.DELIVERED && it.orderStatus != OrderStatus.CANCELLED }})", "DELIVERED" to "Delivered (${orders.count { it.orderStatus == OrderStatus.DELIVERED }})").forEach { (key, label) ->
                Surface(
                    color = if (filterStatus == key) LoveRedPrimary else Color.White,
                    shape = RoundedCornerShape(10.dp),
                    border = androidx.compose.foundation.BorderStroke(1.dp, if (filterStatus == key) LoveRedPrimary else Color(0xFFE2E8F0)),
                    modifier = Modifier.clickable { filterStatus = key }
                ) {
                    Text(
                        text = label,
                        fontSize = 12.sp,
                        fontWeight = FontWeight.Bold,
                        color = if (filterStatus == key) Color.White else TextPrimary,
                        modifier = Modifier.padding(horizontal = 12.dp, vertical = 8.dp)
                    )
                }
            }
        }

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

        if (filteredOrders.isEmpty()) {
            Box(
                modifier = Modifier.fillMaxSize(),
                contentAlignment = Alignment.Center
            ) {
                Text(text = "No orders found in this filter", color = TextSecondary, fontSize = 14.sp)
            }
        } else {
            LazyColumn(
                modifier = Modifier.fillMaxSize(),
                contentPadding = PaddingValues(bottom = 72.dp),
                verticalArrangement = Arrangement.spacedBy(12.dp)
            ) {
                items(filteredOrders) { order ->
                    AdminOrderCard(
                        order = order,
                        onUpdateStatus = { newStatus ->
                            adminViewModel.updateOrderStatus(order.orderId, newStatus)
                        },
                        onAssignRiderClick = {
                            orderToAssignRider = order
                        },
                        onVerifyPayment = {
                            adminViewModel.verifyPayment(order.orderId, order.upiTransactionId.ifBlank { "UPI-REC-${System.currentTimeMillis() % 10000}" })
                        }
                    )
                }
            }
        }
    }

    // Assign Rider Modal
    orderToAssignRider?.let { order ->
        AssignRiderDialog(
            order = order,
            riders = riders,
            onDismiss = { orderToAssignRider = null },
            onAssign = { rider ->
                adminViewModel.assignRiderToOrder(order.orderId, rider)
                orderToAssignRider = null
            }
        )
    }
}

@Composable
fun AdminOrderCard(
    order: Order,
    onUpdateStatus: (OrderStatus) -> Unit,
    onAssignRiderClick: () -> Unit,
    onVerifyPayment: () -> Unit = {}
) {
    val dateStr = SimpleDateFormat("dd MMM, hh:mm a", Locale.getDefault()).format(Date(order.timestamp))

    Card(
        shape = RoundedCornerShape(16.dp),
        colors = CardDefaults.cardColors(containerColor = Color.White),
        elevation = CardDefaults.cardElevation(defaultElevation = 2.dp),
        modifier = Modifier.fillMaxWidth().testTag("admin_order_card_${order.orderId}")
    ) {
        Column(modifier = Modifier.padding(14.dp)) {
            // Header Row: Order ID, Time & Status
            Row(
                modifier = Modifier.fillMaxWidth(),
                horizontalArrangement = Arrangement.SpaceBetween,
                verticalAlignment = Alignment.CenterVertically
            ) {
                Column {
                    Text(text = order.orderId, fontWeight = FontWeight.Black, fontSize = 14.sp, color = TextPrimary)
                    Text(text = dateStr, fontSize = 11.sp, color = TextSecondary)
                }
                OrderStatusBadge(status = order.orderStatus)
            }

            HorizontalDivider(color = Color(0xFFF1F5F9), modifier = Modifier.padding(vertical = 8.dp))

            // Customer Info
            Row(verticalAlignment = Alignment.CenterVertically) {
                Icon(Icons.Default.LocationOn, contentDescription = null, tint = LoveRedPrimary, modifier = Modifier.size(16.dp))
                Spacer(modifier = Modifier.width(6.dp))
                Column {
                    Text(
                        text = "${order.customerName} • ${order.customerPhone}",
                        fontWeight = FontWeight.Bold,
                        fontSize = 13.sp,
                        color = TextPrimary
                    )
                    Text(
                        text = order.deliveryAddress,
                        fontSize = 11.sp,
                        color = TextSecondary
                    )
                }
            }

            // Assigned Rider Info if assigned
            if (order.assignedRiderName.isNotBlank()) {
                Spacer(modifier = Modifier.height(6.dp))
                Surface(
                    color = Color(0xFFE8F5E9),
                    shape = RoundedCornerShape(8.dp),
                    modifier = Modifier.fillMaxWidth()
                ) {
                    Row(
                        modifier = Modifier.padding(horizontal = 10.dp, vertical = 6.dp),
                        verticalAlignment = Alignment.CenterVertically
                    ) {
                        Icon(Icons.Default.DeliveryDining, contentDescription = null, tint = FreshVegGreen, modifier = Modifier.size(16.dp))
                        Spacer(modifier = Modifier.width(6.dp))
                        Text(
                            text = "Rider: ${order.assignedRiderName} (${order.assignedRiderVehicle}) • ${order.assignedRiderPhone}",
                            fontSize = 11.sp,
                            fontWeight = FontWeight.Bold,
                            color = FreshVegGreen
                        )
                    }
                }
            }

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

            // Ordered Items
            Surface(
                color = Color(0xFFF8FAFC),
                shape = RoundedCornerShape(8.dp),
                modifier = Modifier.fillMaxWidth()
            ) {
                Column(modifier = Modifier.padding(10.dp)) {
                    order.items.forEach { item ->
                        Row(
                            modifier = Modifier.fillMaxWidth().padding(vertical = 2.dp),
                            horizontalArrangement = Arrangement.SpaceBetween,
                            verticalAlignment = Alignment.CenterVertically
                        ) {
                            Row(verticalAlignment = Alignment.CenterVertically) {
                                VegNonVegBadge(isVeg = item.isVeg, size = 10.dp)
                                Spacer(modifier = Modifier.width(6.dp))
                                Text(text = "${item.quantity} x ${item.foodName}", fontSize = 12.sp, color = TextPrimary)
                            }
                            Text(text = "₹${(item.price * item.quantity).toInt()}", fontSize = 12.sp, fontWeight = FontWeight.SemiBold)
                        }
                    }
                }
            }

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

            // Bill & Payment status
            Spacer(modifier = Modifier.height(6.dp))
            if (order.paymentMethod != "CASH_ON_DELIVERY") {
                val isPaymentVerified = order.paymentStatus == "CUSTOMER_PAYMENT_RECEIVED" || order.paymentStatus == "PAID"
                Surface(
                    color = if (isPaymentVerified) Color(0xFFE8F5E9) else Color(0xFFFFF3E0),
                    shape = RoundedCornerShape(10.dp),
                    border = androidx.compose.foundation.BorderStroke(1.dp, if (isPaymentVerified) FreshVegGreen else Color(0xFFFF9800)),
                    modifier = Modifier.fillMaxWidth().padding(vertical = 4.dp)
                ) {
                    Column(modifier = Modifier.padding(10.dp)) {
                        Row(
                            verticalAlignment = Alignment.CenterVertically,
                            horizontalArrangement = Arrangement.SpaceBetween,
                            modifier = Modifier.fillMaxWidth()
                        ) {
                            Text(
                                text = if (isPaymentVerified) "✅ CUSTOMER PAYMENT RECEIVED: ₹${order.grandTotal.toInt()}" else "⏳ ONLINE PAYMENT PENDING: ₹${order.grandTotal.toInt()}",
                                fontWeight = FontWeight.Bold,
                                fontSize = 12.sp,
                                color = if (isPaymentVerified) FreshVegGreen else Color(0xFFE65100)
                            )
                            Surface(
                                color = if (isPaymentVerified) FreshVegGreen else Color(0xFFFF9800),
                                shape = RoundedCornerShape(6.dp)
                            ) {
                                Text(
                                    text = if (isPaymentVerified) "PAID" else "PENDING",
                                    color = Color.White,
                                    fontSize = 10.sp,
                                    fontWeight = FontWeight.Bold,
                                    modifier = Modifier.padding(horizontal = 6.dp, vertical = 2.dp)
                                )
                            }
                        }
                        if (order.upiTransactionId.isNotBlank()) {
                            Spacer(modifier = Modifier.height(4.dp))
                            Text(
                                text = "Txn / UTR ID: ${order.upiTransactionId} (${order.paymentMethod})",
                                fontSize = 11.sp,
                                color = TextSecondary,
                                fontWeight = FontWeight.Medium
                            )
                        }

                        if (!isPaymentVerified) {
                            Spacer(modifier = Modifier.height(8.dp))
                            Button(
                                onClick = onVerifyPayment,
                                colors = ButtonDefaults.buttonColors(containerColor = FreshVegGreen),
                                shape = RoundedCornerShape(8.dp),
                                modifier = Modifier.fillMaxWidth().height(34.dp)
                            ) {
                                Text("✅ Customer Payment Received (Confirm ₹${order.grandTotal.toInt()})", fontSize = 11.sp, fontWeight = FontWeight.Bold, color = Color.White)
                            }
                        }
                    }
                }
            } else {
                Row(
                    modifier = Modifier.fillMaxWidth(),
                    horizontalArrangement = Arrangement.SpaceBetween,
                    verticalAlignment = Alignment.CenterVertically
                ) {
                    Text(
                        text = "Total: ₹${order.grandTotal.toInt()} • Cash on Delivery",
                        fontWeight = FontWeight.Bold,
                        fontSize = 12.sp,
                        color = Color(0xFFE65100)
                    )
                }
            }

            Spacer(modifier = Modifier.height(10.dp))

            // Admin Status Progression Action Buttons
            Row(
                modifier = Modifier.fillMaxWidth(),
                horizontalArrangement = Arrangement.spacedBy(8.dp)
            ) {
                when (order.orderStatus) {
                    OrderStatus.PLACED -> {
                        Button(
                            onClick = { onUpdateStatus(OrderStatus.PREPARING) },
                            shape = RoundedCornerShape(10.dp),
                            colors = ButtonDefaults.buttonColors(containerColor = Color(0xFFFF6D00)),
                            modifier = Modifier.weight(1f).height(38.dp)
                        ) {
                            Icon(Icons.Default.Restaurant, contentDescription = null, modifier = Modifier.size(16.dp))
                            Spacer(modifier = Modifier.width(6.dp))
                            Text("Accept & Cook", fontWeight = FontWeight.Bold, fontSize = 12.sp)
                        }
                    }
                    OrderStatus.PREPARING -> {
                        Button(
                            onClick = onAssignRiderClick,
                            shape = RoundedCornerShape(10.dp),
                            colors = ButtonDefaults.buttonColors(containerColor = Color(0xFF0288D1)),
                            modifier = Modifier.weight(1f).height(38.dp).testTag("assign_rider_btn_${order.orderId}")
                        ) {
                            Icon(Icons.Default.DeliveryDining, contentDescription = null, modifier = Modifier.size(16.dp))
                            Spacer(modifier = Modifier.width(6.dp))
                            Text("Assign Rider", fontWeight = FontWeight.Bold, fontSize = 12.sp)
                        }
                    }
                    OrderStatus.OUT_FOR_DELIVERY -> {
                        Button(
                            onClick = { onUpdateStatus(OrderStatus.DELIVERED) },
                            shape = RoundedCornerShape(10.dp),
                            colors = ButtonDefaults.buttonColors(containerColor = FreshVegGreen),
                            modifier = Modifier.weight(1f).height(38.dp)
                        ) {
                            Icon(Icons.Default.Check, contentDescription = null, modifier = Modifier.size(16.dp))
                            Spacer(modifier = Modifier.width(6.dp))
                            Text("Mark Delivered", fontWeight = FontWeight.Bold, fontSize = 12.sp)
                        }
                    }
                    OrderStatus.DELIVERED, OrderStatus.CANCELLED -> {
                        // Completed
                    }
                }

                if (order.orderStatus != OrderStatus.DELIVERED && order.orderStatus != OrderStatus.CANCELLED) {
                    OutlinedButton(
                        onClick = { onUpdateStatus(OrderStatus.CANCELLED) },
                        shape = RoundedCornerShape(10.dp),
                        modifier = Modifier.height(38.dp)
                    ) {
                        Text("Cancel", color = Color.Red, fontSize = 12.sp)
                    }
                }
            }
        }
    }
}

@Composable
fun AssignRiderDialog(
    order: Order,
    riders: List<DeliveryRider>,
    onDismiss: () -> Unit,
    onAssign: (DeliveryRider) -> Unit
) {
    AlertDialog(
        onDismissRequest = onDismiss,
        title = {
            Column {
                Text(text = "Assign Rider to Order", fontWeight = FontWeight.Bold, fontSize = 16.sp)
                Text(text = "Order #${order.orderId} • To: ${order.customerName}", fontSize = 12.sp, color = TextSecondary)
            }
        },
        text = {
            Column(
                modifier = Modifier.fillMaxWidth(),
                verticalArrangement = Arrangement.spacedBy(8.dp)
            ) {
                Text(text = "Select a Kumarghat Delivery Partner:", fontSize = 12.sp, color = TextSecondary)

                riders.forEach { rider ->
                    val isAvailable = rider.status == RiderStatus.AVAILABLE
                    Surface(
                        color = if (isAvailable) Color(0xFFF0FDF4) else Color(0xFFF8FAFC),
                        shape = RoundedCornerShape(10.dp),
                        border = androidx.compose.foundation.BorderStroke(
                            1.dp,
                            if (isAvailable) FreshVegGreen else Color(0xFFE2E8F0)
                        ),
                        modifier = Modifier
                            .fillMaxWidth()
                            .clickable { onAssign(rider) }
                            .padding(vertical = 2.dp)
                    ) {
                        Row(
                            modifier = Modifier.padding(10.dp),
                            verticalAlignment = Alignment.CenterVertically,
                            horizontalArrangement = Arrangement.SpaceBetween
                        ) {
                            Row(verticalAlignment = Alignment.CenterVertically) {
                                Box(
                                    modifier = Modifier
                                        .size(32.dp)
                                        .background(if (isAvailable) FreshVegGreen.copy(alpha = 0.15f) else Color.LightGray.copy(alpha = 0.2f), CircleShape),
                                    contentAlignment = Alignment.Center
                                ) {
                                    Icon(
                                        Icons.Default.DeliveryDining,
                                        contentDescription = null,
                                        tint = if (isAvailable) FreshVegGreen else Color.Gray,
                                        modifier = Modifier.size(18.dp)
                                    )
                                }
                                Spacer(modifier = Modifier.width(10.dp))
                                Column {
                                    Text(text = rider.name, fontWeight = FontWeight.Bold, fontSize = 13.sp)
                                    Text(text = "${rider.vehicleNumber} • ${rider.phone}", fontSize = 10.sp, color = TextSecondary)
                                }
                            }

                            Surface(
                                color = if (isAvailable) FreshVegGreen else Color.Gray,
                                shape = RoundedCornerShape(6.dp)
                            ) {
                                Text(
                                    text = if (isAvailable) "Assign" else rider.status.label,
                                    color = Color.White,
                                    fontSize = 10.sp,
                                    fontWeight = FontWeight.Bold,
                                    modifier = Modifier.padding(horizontal = 6.dp, vertical = 3.dp)
                                )
                            }
                        }
                    }
                }
            }
        },
        confirmButton = {},
        dismissButton = {
            TextButton(onClick = onDismiss) {
                Text("Cancel", color = TextSecondary)
            }
        }
    )
}