+-----------------------------------------------------------------------------------------+
|                  SwiftUI vs Jetpack Compose Architectural Matrix (2026)                 |
+-----------------------------------------------------------------------------------------+

SWIFTUI (The Apple Native Value-Type Standard)
- Core Model: Value-type View structs created on the stack (Ultra-lightweight memory allocation).
- State Engine: '@Observable' Macro (Swift 6 Observation framework) + Attribute Graph.
- Rendering: Backed by Apple CoreAnimation / Metal layer compositing.
- Best for: Pure native iOS, iPadOS, macOS, watchOS, and visionOS applications.

JETPACK COMPOSE (The Kotlin Compiler Memoization Standard)
- Core Model: Composable functions annotated with '@Composable' transformed by Kotlin Compiler.
- State Engine: 'StateFlow' (Kotlin Coroutines) + Positional Memoization (Slot Table).
- Rendering: Direct rendering via Skia / Android RenderNode pipeline.
- Best for: Pure native Android applications and cross-platform Compose Multiplatform (CMP).

+-----------------------------------------------------------------------------------------+
|                  How UI Trees Avoid Expensive Redraws on State Changes                  |
+-----------------------------------------------------------------------------------------+

SWIFTUI ATTRIBUTE GRAPH (iOS):
[State Property Mutates: user.balance = $450]
                 |
                 v
[Attribute Graph identifies EXACT subview node registered as an observer!]
                 |
                 v
[Only the Text(user.balance) struct is re-evaluated! Parent views are untouched!]

JETPACK COMPOSE SLOT TABLE & POSITIONAL MEMOIZATION (Android):
[StateFlow Emits: UiState(balance = 450)]
                 |
                 v
[Compose Compiler inspects function parameters at runtime!]
                 |
                 +---> [Parameter 'userData' has not changed -> SKIPS Composable entirely!]
                 +---> [Parameter 'balance' changed -> RECOMPOSES only that specific slot!]

// State/CheckoutState.swift
import SwiftUI

// 1. Immutable State Data Model
struct CheckoutUiState: Equatable {
    var items: [CartItem] = []
    var isProcessing: Bool = false
    var errorMessage: String? = nil
    var orderSuccessId: String? = nil
    
    var totalAmount: Double {
        items.reduce(0) { $0 + ($1.price * Double($1.quantity)) }
    }
}

// 2. Modern SwiftUI 6 Observable ViewModel (Zero Boilerplate!)
@Observable
final class CheckoutViewModel {
    private(set) var state = CheckoutUiState()
    
    func handleIntent(_ intent: CheckoutIntent) async {
        switch intent {
        case .loadCart:
            state.items = [CartItem(id: "1", name: "Pro Headphones", price: 299.0, quantity: 1)]
        case .submitPayment:
            state.isProcessing = true
            state.errorMessage = nil
            do {
                // Simulate asynchronous payment API call
                try await Task.sleep(nanoseconds: 1_000_000_000)
                state.orderSuccessId = "ORD-98420"
            } catch {
                state.errorMessage = "Payment failed. Please retry."
            }
            state.isProcessing = false
        }
    }
}

enum CheckoutIntent {
    case loadCart
    case submitPayment
}

// Views/CheckoutView.swift
import SwiftUI

struct CheckoutView: View {
    @State private var viewModel = CheckoutViewModel()

    var body: some View {
        VStack(spacing: 20) {
            Text("Total: $\(viewModel.state.totalAmount, specifier: "%.2f")")
                .font(.largeTitle.bold())
            
            if viewModel.state.isProcessing {
                ProgressView("Authorizing Payment...")
            } else {
                Button(action: {
                    Task { await viewModel.handleIntent(.submitPayment) }
                }) {
                    Text("Pay Now")
                        .font(.headline)
                        .frame(maxWidth: .infinity)
                        .padding()
                        .background(Color.red)
                        .foregroundColor(.white)
                        .cornerRadius(12)
                }
            }
            
            if let error = viewModel.state.errorMessage {
                Text(error).foregroundColor(.red)
            }
        }
        .padding()
        .task {
            await viewModel.handleIntent(.loadCart)
        }
    }
}

// ui/checkout/CheckoutViewModel.kt
package com.mojostudio.checkout

import androidx.compose.runtime.Immutable
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.asStateFlow
import kotlinx.coroutines.flow.update
import kotlinx.coroutines.launch

// 1. Immutable UI State with Compose Compiler Stability Guarantee
@Immutable
data class CheckoutUiState(
    val items: List<CartItem> = emptyList(),
    val isProcessing: Boolean = false,
    val errorMessage: String? = null,
    val orderSuccessId: String? = null
) {
    val totalAmount: Double get() = items.sumOf { it.price * it.quantity }
}

sealed interface CheckoutIntent {
    data object LoadCart : CheckoutIntent
    data object SubmitPayment : CheckoutIntent
}

class CheckoutViewModel : ViewModel() {
    private val _uiState = MutableStateFlow(CheckoutUiState())
    val uiState: StateFlow<CheckoutUiState> = _uiState.asStateFlow()

    fun handleIntent(intent: CheckoutIntent) {
        when (intent) {
            is CheckoutIntent.LoadCart -> {
                _uiState.update { it.copy(items = listOf(CartItem("1", "Pro Headphones", 299.0, 1))) }
            }
            is CheckoutIntent.SubmitPayment -> {
                viewModelScope.launch {
                    _uiState.update { it.copy(isProcessing = true, errorMessage = null) }
                    delay(1000) // Simulate payment API
                    _uiState.update { it.copy(isProcessing = false, orderSuccessId = "ORD-98420") }
                }
            }
        }
    }
}

// ui/checkout/CheckoutScreen.kt
package com.mojostudio.checkout

import androidx.compose.foundation.layout.*
import androidx.compose.material3.*
import androidx.compose.runtime.*
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp
import androidx.lifecycle.compose.collectAsStateWithLifecycle

@Composable
fun CheckoutScreen(
    viewModel: CheckoutViewModel,
    modifier: Modifier = Modifier
) {
    // Collect lifecycle-aware state stream
    val state by viewModel.uiState.collectAsStateWithLifecycle()

    LaunchedEffect(Unit) {
        viewModel.handleIntent(CheckoutIntent.LoadCart)
    }

    Column(
        modifier = modifier.fillMaxSize().padding(16.dp),
        verticalArrangement = Arrangement.spacedBy(16.dp)
    ) {
        Text(
            text = "Total: $${state.totalAmount}",
            style = MaterialTheme.typography.headlineLarge
        )

        if (state.isProcessing) {
            CircularProgressIndicator()
        } else {
            Button(
                onClick = { viewModel.handleIntent(CheckoutIntent.SubmitPayment) },
                modifier = Modifier.fillMaxWidth(),
                colors = ButtonDefaults.buttonColors(containerColor = Color.Red)
            ) {
                Text("Pay Now")
            }
        }

        state.errorMessage?.let { error ->
            Text(text = error, color = Color.Red)
        }
    }
}

       +-------------------------------------------------------------+
       |             CPU Utilization on Dynamic State Mutation (%)   |
       +-------------------------------------------------------------+
 Legacy Imperative (UIKit / Android XML) | ===================== [18.2%]
 Modern SwiftUI 6 (@Observable Macro)   | === [2.4%] (87% CPU Savings!)
 Jetpack Compose (@Immutable StateFlow)  | === [2.8%] (84% CPU Savings!)
                                         +-------------------------------------+
                                         0%      5%      10%     15%     20%