package com.example.ui.customer

import androidx.compose.animation.AnimatedVisibility
import androidx.compose.foundation.Image
import androidx.compose.foundation.background
import androidx.compose.foundation.border
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.fillMaxHeight
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.automirrored.filled.ArrowBack
import androidx.compose.material.icons.filled.Search
import androidx.compose.material.icons.filled.Star
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.IconButton
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.draw.clip
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.platform.testTag
import androidx.compose.ui.res.painterResource
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.style.TextOverflow
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import com.example.R
import com.example.data.model.FoodItem
import com.example.ui.components.FoodItemImage
import com.example.ui.components.FoodReviewsBottomSheet
import com.example.ui.components.QuantityStepper
import com.example.ui.components.VegNonVegBadge
import com.example.ui.components.WriteReviewDialog
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.CustomerNavScreen
import com.example.viewmodel.CustomerViewModel
import java.util.Locale

@Composable
fun MenuScreen(
    customerViewModel: CustomerViewModel,
    modifier: Modifier = Modifier
) {
    val allItems by customerViewModel.allFoodItems.collectAsState()
    val filteredItems by customerViewModel.filteredFoodItems.collectAsState()
    val selectedCategory by customerViewModel.selectedCategory.collectAsState()
    val selectedDiet by customerViewModel.selectedDietFilter.collectAsState()
    val searchQuery by customerViewModel.searchQuery.collectAsState()
    val cartItems by customerViewModel.cartItems.collectAsState()
    val allReviews by customerViewModel.allReviews.collectAsState()

    var selectedDishForReviews by remember { mutableStateOf<FoodItem?>(null) }
    var selectedDishForWriteReview by remember { mutableStateOf<FoodItem?>(null) }

    // Distinct categories with counts
    val categoryList = listOf("All") + allItems.map { it.category }.distinct()

    Box(modifier = modifier.fillMaxSize()) {
        Column(
            modifier = Modifier
                .fillMaxSize()
                .background(Color(0xFFF8F9FD))
        ) {
            // Top Bar with back button and search
            Surface(
                color = Color.White,
                shadowElevation = 2.dp,
                modifier = Modifier.fillMaxWidth()
            ) {
                Row(
                    modifier = Modifier
                        .fillMaxWidth()
                        .padding(horizontal = 8.dp, vertical = 6.dp),
                    verticalAlignment = Alignment.CenterVertically
                ) {
                    IconButton(
                        onClick = { customerViewModel.navigateTo(CustomerNavScreen.Home) },
                        modifier = Modifier.testTag("menu_back_button")
                    ) {
                        Icon(
                            imageVector = Icons.AutoMirrored.Filled.ArrowBack,
                            contentDescription = "Back",
                            tint = TextPrimary
                        )
                    }

                    OutlinedTextField(
                        value = searchQuery,
                        onValueChange = { customerViewModel.searchQuery.value = it },
                        placeholder = { Text("Search delicious items...", fontSize = 13.sp, color = Color.Gray) },
                        leadingIcon = {
                            Icon(Icons.Default.Search, contentDescription = null, tint = LoveRedPrimary, modifier = Modifier.size(18.dp))
                        },
                        singleLine = true,
                        shape = RoundedCornerShape(20.dp),
                        colors = OutlinedTextFieldDefaults.colors(
                            focusedTextColor = Color(0xFF1E2022),
                            unfocusedTextColor = Color(0xFF1E2022),
                            focusedContainerColor = Color(0xFFF1F5F9),
                            unfocusedContainerColor = Color(0xFFF1F5F9),
                            cursorColor = LoveRedPrimary,
                            focusedBorderColor = LoveRedPrimary,
                            unfocusedBorderColor = Color.Transparent
                        ),
                        modifier = Modifier
                            .weight(1f)
                            .height(46.dp)
                            .testTag("menu_search_field")
                    )

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

                    Surface(
                        color = FreshVegGreen,
                        shape = RoundedCornerShape(8.dp),
                        modifier = Modifier.padding(end = 4.dp)
                    ) {
                        Row(
                            modifier = Modifier.padding(horizontal = 6.dp, vertical = 4.dp),
                            verticalAlignment = Alignment.CenterVertically
                        ) {
                            Icon(Icons.Default.Star, contentDescription = null, tint = Color.White, modifier = Modifier.size(12.dp))
                            Spacer(modifier = Modifier.width(2.dp))
                            Text(text = "4.9", color = Color.White, fontSize = 11.sp, fontWeight = FontWeight.Bold)
                        }
                    }
                }
            }

            // Veg / Non-Veg Filter Chips
            Surface(
                color = Color.White,
                modifier = Modifier.fillMaxWidth()
            ) {
                Row(
                    modifier = Modifier
                        .fillMaxWidth()
                        .padding(horizontal = 16.dp, vertical = 8.dp),
                    horizontalArrangement = Arrangement.spacedBy(8.dp),
                    verticalAlignment = Alignment.CenterVertically
                ) {
                    Text(
                        text = "Filter: ",
                        fontSize = 12.sp,
                        fontWeight = FontWeight.SemiBold,
                        color = TextSecondary
                    )

                    DietFilterChip(
                        label = "All (${allItems.size})",
                        isSelected = selectedDiet == "All",
                        onClick = { customerViewModel.selectedDietFilter.value = "All" }
                    )

                    DietFilterChip(
                        label = "Veg (${allItems.count { it.isVeg }})",
                        isVeg = true,
                        isSelected = selectedDiet == "Veg",
                        onClick = { customerViewModel.selectedDietFilter.value = "Veg" }
                    )

                    DietFilterChip(
                        label = "Non-Veg (${allItems.count { !it.isVeg }})",
                        isNonVeg = true,
                        isSelected = selectedDiet == "Non-Veg",
                        onClick = { customerViewModel.selectedDietFilter.value = "Non-Veg" }
                    )
                }
            }

            // Split Layout: Left Category Rail & Right Dishes List
            Row(
                modifier = Modifier
                    .fillMaxSize()
                    .padding(bottom = 72.dp)
            ) {
                // Left Category Navigation Rail
                Surface(
                    color = Color.White,
                    modifier = Modifier
                        .width(96.dp)
                        .fillMaxHeight(),
                    border = androidx.compose.foundation.BorderStroke(1.dp, Color(0xFFF1F5F9))
                ) {
                    LazyColumn(
                        modifier = Modifier.fillMaxSize(),
                        contentPadding = PaddingValues(vertical = 8.dp)
                    ) {
                        items(categoryList) { category ->
                            val count = if (category == "All") allItems.size else allItems.count { it.category == category }
                            val isSelected = selectedCategory == category

                            Column(
                                modifier = Modifier
                                    .fillMaxWidth()
                                    .clickable { customerViewModel.selectedCategory.value = category }
                                    .background(if (isSelected) Color(0xFFFFF1F2) else Color.Transparent)
                                    .border(
                                        width = if (isSelected) 3.dp else 0.dp,
                                        color = if (isSelected) LoveRedPrimary else Color.Transparent
                                    )
                                    .padding(vertical = 10.dp, horizontal = 4.dp),
                                horizontalAlignment = Alignment.CenterHorizontally
                            ) {
                                Box(
                                    modifier = Modifier
                                        .size(38.dp)
                                        .clip(CircleShape)
                                        .background(if (isSelected) LoveRedPrimary.copy(alpha = 0.15f) else Color(0xFFF8FAFC)),
                                    contentAlignment = Alignment.Center
                                ) {
                                    Text(
                                        text = getCategoryEmoji(category),
                                        fontSize = 18.sp
                                    )
                                }
                                Spacer(modifier = Modifier.height(4.dp))
                                Text(
                                    text = category,
                                    fontSize = 11.sp,
                                    fontWeight = if (isSelected) FontWeight.Bold else FontWeight.Medium,
                                    color = if (isSelected) LoveRedPrimary else TextPrimary,
                                    maxLines = 2,
                                    overflow = TextOverflow.Ellipsis,
                                    modifier = Modifier.padding(horizontal = 2.dp)
                                )
                                Text(
                                    text = "$count items",
                                    fontSize = 9.sp,
                                    color = TextSecondary
                                )
                            }
                        }
                    }
                }

                // Right Items List
                LazyColumn(
                    modifier = Modifier
                        .weight(1f)
                        .fillMaxHeight()
                        .padding(horizontal = 10.dp),
                    contentPadding = PaddingValues(top = 8.dp, bottom = 48.dp),
                    verticalArrangement = Arrangement.spacedBy(10.dp)
                ) {
                    if (filteredItems.isEmpty()) {
                        item {
                            Column(
                                modifier = Modifier
                                    .fillMaxWidth()
                                    .padding(top = 48.dp),
                                horizontalAlignment = Alignment.CenterHorizontally
                            ) {
                                Text("No dishes found in this filter", color = TextSecondary, fontSize = 13.sp)
                            }
                        }
                    } else {
                        items(filteredItems) { item ->
                            val qty = cartItems[item.id]?.quantity ?: 0
                            MenuDishCard(
                                item = item,
                                quantity = qty,
                                onAdd = { customerViewModel.addToCart(item) },
                                onIncrement = { customerViewModel.addToCart(item) },
                                onDecrement = { customerViewModel.decrementOrRemoveFromCart(item) },
                                onReviewClick = { selectedDishForReviews = item }
                            )
                        }
                    }
                }
            }
        }

        // Ratings & Written Reviews Bottom Sheet
        selectedDishForReviews?.let { foodItem ->
            val dishReviews = allReviews.filter { it.foodItemId == foodItem.id }
            FoodReviewsBottomSheet(
                foodItem = foodItem,
                reviews = dishReviews,
                onDismiss = { selectedDishForReviews = null },
                onWriteReviewClicked = {
                    val target = selectedDishForReviews
                    selectedDishForReviews = null
                    selectedDishForWriteReview = target
                }
            )
        }

        // Write Customer Review Dialog
        selectedDishForWriteReview?.let { foodItem ->
            WriteReviewDialog(
                foodItem = foodItem,
                onDismiss = { selectedDishForWriteReview = null },
                onSubmit = { rating, reviewText ->
                    customerViewModel.submitFoodReview(foodItem, rating, reviewText)
                    selectedDishForWriteReview = null
                }
            )
        }
    }
}

@Composable
fun DietFilterChip(
    label: String,
    isSelected: Boolean,
    onClick: () -> Unit,
    isVeg: Boolean = false,
    isNonVeg: Boolean = false
) {
    Surface(
        shape = RoundedCornerShape(16.dp),
        color = if (isSelected) Color(0xFF1E293B) else Color(0xFFF1F5F9),
        modifier = Modifier
            .clickable(onClick = onClick)
            .testTag("diet_chip_$label")
    ) {
        Row(
            modifier = Modifier.padding(horizontal = 10.dp, vertical = 6.dp),
            verticalAlignment = Alignment.CenterVertically
        ) {
            if (isVeg) {
                VegNonVegBadge(isVeg = true, size = 12.dp)
                Spacer(modifier = Modifier.width(4.dp))
            } else if (isNonVeg) {
                VegNonVegBadge(isVeg = false, size = 12.dp)
                Spacer(modifier = Modifier.width(4.dp))
            }
            Text(
                text = label,
                fontSize = 11.sp,
                fontWeight = if (isSelected) FontWeight.Bold else FontWeight.Medium,
                color = if (isSelected) Color.White else TextPrimary
            )
        }
    }
}

@Composable
fun MenuDishCard(
    item: FoodItem,
    quantity: Int,
    onAdd: () -> Unit,
    onIncrement: () -> Unit,
    onDecrement: () -> Unit,
    onReviewClick: () -> Unit
) {
    Card(
        shape = RoundedCornerShape(12.dp),
        colors = CardDefaults.cardColors(containerColor = Color.White),
        elevation = CardDefaults.cardElevation(defaultElevation = 1.dp),
        modifier = Modifier.fillMaxWidth()
    ) {
        Column(modifier = Modifier.padding(10.dp)) {
            // Food item picture
            Box(
                modifier = Modifier
                    .fillMaxWidth()
                    .height(110.dp)
                    .clip(RoundedCornerShape(8.dp))
            ) {
                FoodItemImage(
                    imageUri = item.imageUri,
                    contentDescription = item.name,
                    modifier = Modifier.fillMaxSize()
                )

                VegNonVegBadge(
                    isVeg = item.isVeg,
                    modifier = Modifier
                        .align(Alignment.TopStart)
                        .padding(6.dp)
                )

                if (item.isBestSeller) {
                    Surface(
                        color = Color(0xFFFF5722),
                        shape = RoundedCornerShape(bottomEnd = 8.dp),
                        modifier = Modifier.align(Alignment.TopEnd)
                    ) {
                        Text(
                            text = "Trending 🔥",
                            color = Color.White,
                            fontSize = 9.sp,
                            fontWeight = FontWeight.Bold,
                            modifier = Modifier.padding(horizontal = 6.dp, vertical = 2.dp)
                        )
                    }
                }
            }

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

            Text(
                text = item.name,
                fontWeight = FontWeight.Bold,
                fontSize = 14.sp,
                color = TextPrimary,
                maxLines = 1,
                overflow = TextOverflow.Ellipsis
            )

            Text(
                text = item.description,
                fontSize = 11.sp,
                color = TextSecondary,
                maxLines = 1,
                overflow = TextOverflow.Ellipsis
            )

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

            // Rating Badge & Customer Written Reviews Trigger
            Row(
                modifier = Modifier
                    .clip(RoundedCornerShape(6.dp))
                    .background(AccentGold.copy(alpha = 0.12f))
                    .clickable { onReviewClick() }
                    .padding(horizontal = 6.dp, vertical = 3.dp),
                verticalAlignment = Alignment.CenterVertically
            ) {
                Icon(
                    imageVector = Icons.Default.Star,
                    contentDescription = null,
                    tint = AccentGold,
                    modifier = Modifier.size(13.dp)
                )
                Spacer(modifier = Modifier.width(3.dp))
                Text(
                    text = String.format(Locale.getDefault(), "%.1f", item.rating),
                    fontWeight = FontWeight.Bold,
                    fontSize = 11.sp,
                    color = TextPrimary
                )
                Spacer(modifier = Modifier.width(4.dp))
                Text(
                    text = "(${item.reviewCount} reviews) >",
                    fontSize = 10.sp,
                    color = LoveRedPrimary,
                    fontWeight = FontWeight.SemiBold
                )
            }

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

            Row(
                modifier = Modifier.fillMaxWidth(),
                verticalAlignment = Alignment.CenterVertically,
                horizontalArrangement = Arrangement.SpaceBetween
            ) {
                Text(
                    text = "₹${item.price.toInt()}",
                    fontWeight = FontWeight.Black,
                    fontSize = 15.sp,
                    color = LoveRedPrimary
                )

                if (quantity > 0) {
                    QuantityStepper(
                        quantity = quantity,
                        onIncrement = onIncrement,
                        onDecrement = onDecrement
                    )
                } else {
                    Button(
                        onClick = onAdd,
                        shape = RoundedCornerShape(8.dp),
                        colors = ButtonDefaults.buttonColors(containerColor = Color(0xFFFFF1F2)),
                        border = androidx.compose.foundation.BorderStroke(1.dp, LoveRedPrimary),
                        contentPadding = PaddingValues(horizontal = 14.dp, vertical = 2.dp),
                        modifier = Modifier.height(30.dp).testTag("menu_add_${item.id}")
                    ) {
                        Text(
                            text = "ADD",
                            color = LoveRedPrimary,
                            fontWeight = FontWeight.Black,
                            fontSize = 11.sp
                        )
                    }
                }
            }
        }
    }
}

fun getCategoryEmoji(category: String): String {
    return when {
        category.contains("Biryani", ignoreCase = true) -> "🍗"
        category.contains("Quick", ignoreCase = true) -> "🍟"
        category.contains("Starter", ignoreCase = true) -> "🍢"
        category.contains("Burger", ignoreCase = true) -> "🍔"
        category.contains("Roll", ignoreCase = true) -> "🌯"
        category.contains("Main", ignoreCase = true) -> "🍛"
        category.contains("Pasta", ignoreCase = true) -> "🍝"
        category.contains("Beverage", ignoreCase = true) || category.contains("Shake", ignoreCase = true) -> "🥤"
        category.contains("Rice", ignoreCase = true) || category.contains("Noodle", ignoreCase = true) -> "🍜"
        else -> "🍽️"
    }
}