# SimpleX Chat iOS -- Navigation Architecture

> Technical specification for the navigation stack, deep linking, sheet presentation, and call overlay.
>
> Related specs: [Chat List](chat-list.md) | [Chat View](chat-view.md) | [State Management](../state.md) | [README](../README.md)
> Related product: [Product Overview](../../product/README.md)

**Source:** [`ContentView.swift`](../../Shared/ContentView.swift) | [`NewChatView.swift`](../../Shared/Views/NewChat/NewChatView.swift) | [`SettingsView.swift`](../../Shared/Views/UserSettings/SettingsView.swift) | [`OnboardingView.swift`](../../Shared/Views/Onboarding/OnboardingView.swift) | [`UserProfilesView.swift`](../../Shared/Views/UserSettings/UserProfilesView.swift)

---

## Table of Contents

1. [Overview](#1-overview)
2. [Root View -- ContentView](#2-root-view)
3. [Navigation Stack](#3-navigation-stack)
4. [Sheet Presentation](#4-sheet-presentation)
5. [Deep Linking](#5-deep-linking)
6. [Call Overlay](#6-call-overlay)
7. [Authentication Gate](#7-authentication-gate)
8. [Onboarding Flow](#8-onboarding-flow)

---

## 1. Overview

The app's navigation follows a hierarchical model with a single navigation stack rooted in `ContentView`. Modal sheets and full-screen overlays augment the primary navigation path.

```
SimpleXApp
└── ContentView (root)
    ├── Authentication gate (LocalAuthView / SetAppPasscodeView)
    ├── Onboarding flow (if first launch / migration)
    ├── Main content
    │   └── NavigationStack / NavigationView
    │       ├── ChatListView (root of stack)
    │       │   ├── ChatView (pushed)
    │       │   │   ├── ChatInfoView / GroupChatInfoView (pushed)
    │       │   │   └── ChatItemInfoView (pushed)
    │       │   └── ContactConnectionInfo (pushed)
    │       └── Settings views (pushed)
    ├── Sheets (modal)
    │   ├── UserPicker
    │   ├── NewChatView
    │   ├── WhatsNew / Notices
    │   └── Settings sub-views
    └── Overlays (always on top)
        ├── Active call banner (when call active)
        └── ActiveCallView (full-screen call)
```

---

## 2. Root View -- [`ContentView`](../../Shared/ContentView.swift#L24)

**File**: [`Shared/ContentView.swift`](../../Shared/ContentView.swift)

`ContentView` is the root view injected by `SimpleXApp`. It manages:

### [Environment](../../Shared/ContentView.swift#L25-L37)
- `@EnvironmentObject var chatModel: ChatModel`
- `@EnvironmentObject var theme: AppTheme`
- `@Environment(\.scenePhase) var scenePhase`

### [Key State](../../Shared/ContentView.swift#L35-L52)
| Property | Type | Purpose |
|----------|------|---------|
| [`contentAccessAuthenticationExtended`](../../Shared/ContentView.swift#L35) | `Bool` | Passed at init to avoid re-render timing issues |
| [`automaticAuthenticationAttempted`](../../Shared/ContentView.swift#L38) | `Bool` | Whether biometric auth was auto-attempted |
| [`waitingForOrPassedAuth`](../../Shared/ContentView.swift#L51) | `Bool` | Whether auth gate should show |
| [`chatListUserPickerSheet`](../../Shared/ContentView.swift#L52) | `UserPickerSheet?` | Active user picker sheet |

### [View Selection Logic](../../Shared/ContentView.swift#L60-L80)

```swift
// Simplified decision tree in ContentView.body:
if !prefPerformLA || accessAuthenticated {
    contentView()   // Main app content
} else {
    lockButton()    // Authentication required
}
```

The [`contentView()`](../../Shared/ContentView.swift#L169) function further decides:
- If `chatModel.onboardingStage != .onboardingComplete`: show [onboarding](../../Shared/ContentView.swift#L174)
- If `chatModel.migrationState != nil`: show migration UI
- Otherwise: show `ChatListView` in a navigation container

---

## 3. Navigation Stack

### iOS Version Compatibility

**File**: [`Shared/Views/Helpers/NavStackCompat.swift`](../../Shared/Views/Helpers/NavStackCompat.swift)

The app supports iOS 15+ and uses a compatibility wrapper ([`NavStackCompat`](../../Shared/Views/Helpers/NavStackCompat.swift#L11)):

```swift
// NavStackCompat provides:
// - NavigationStack (iOS 16+): programmatic navigation via NavigationPath
// - NavigationView (iOS 15): classic NavigationLink-based navigation
```

### Primary Navigation Path

```
ChatListView
    │
    ├─[tap chat]─→ ChatView
    │                  │
    │                  ├─[tap info]─→ ChatInfoView (direct)
    │                  │              └─→ VerifyCodeView, etc.
    │                  │
    │                  ├─[tap info]─→ GroupChatInfoView (group)
    │                  │              ├─→ GroupMemberInfoView
    │                  │              ├─→ GroupProfileView
    │                  │              └─→ GroupLinkView
    │                  │
    │                  └─[tap message info]─→ ChatItemInfoView
    │
    ├─[tap connection]─→ ContactConnectionInfo
    │
    └─[settings]─→ SettingsView
                       ├─→ NotificationsView
                       ├─→ NetworkAndServers
                       ├─→ AppearanceSettings
                       ├─→ PrivacySettings
                       ├─→ DatabaseView
                       └─→ UserProfilesView
```

### Navigation Trigger

Chat navigation is triggered by setting `ChatModel.chatId`:

```swift
// In ChatListNavLink:
ItemsModel.shared.loadOpenChat(chatId) {
    // This sets ChatModel.chatId = chatId after a 250ms delay
    // allowing navigation animation to start smoothly
}
```

---

## 4. Sheet Presentation

Sheets are presented modally on top of the navigation stack:

| Sheet | Trigger | Content |
|-------|---------|---------|
| UserPicker | Tap user avatar in nav bar | User list, settings shortcuts |
| [`NewChatView`](../../Shared/Views/NewChat/NewChatView.swift#L78) | Tap FAB / "+" button | Create link, scan QR, paste link, new group |
| WhatsNew | App update detected | Release notes |
| AddGroupView | "New Group" action | Group creation wizard |
| ConnectDesktopView | Settings > Desktop | Remote desktop pairing |
| MigrateFromDevice | Settings > Migration | Device export |
| MigrateToDevice | Onboarding migration | Device import |
| [LocalAuthView](../../Shared/ContentView.swift#L95) | App foreground after background | Biometric/passcode auth |

### Sheet Management

Sheets use SwiftUI `.sheet(item:)` or `.sheet(isPresented:)` modifiers on `ContentView` and `ChatListView`. Some sheets use the centralized [`AppSheetState.shared`](../../Shared/ContentView.swift#L29) observable for coordination:

```swift
class AppSheetState: ObservableObject {
    static let shared = AppSheetState()
    var scenePhaseActive: Bool = false
    // ... sheet state coordination
}
```

---

## 5. Deep Linking

### Notification Deep Link

When the user taps a notification:

1. `NtfManager.processNotificationResponse()` extracts the `chatId` from notification payload
2. If a different user: calls `changeActiveUser(userId:)`
3. Sets `ChatModel.chatId = chatId` to navigate to the conversation
4. If the app was in background: the notification response is stored in `ChatModel.notificationResponse` and processed when the app becomes active

### [URL Deep Link](../../Shared/ContentView.swift#L281)

SimpleX links (`simplex:/chat#...`) are handled via [`connectViaUrl()`](../../Shared/ContentView.swift#L439):

```swift
.onOpenURL { url in
    if AppChatState.shared.value == .active {
        chatModel.appOpenUrl = url      // Process immediately
    } else {
        chatModel.appOpenUrlLater = url // Process when active
    }
}
```

URL processing routes to the appropriate connection flow (join group, add contact, etc.) via [`planAndConnect()`](../../Shared/Views/NewChat/NewChatView.swift#L1181).

### Call Deep Link

Call invitations from notifications:
1. `NtfManager` detects `ntfActionAcceptCall` action
2. Sets `ChatModel.ntfCallInvitationAction = (chatId, .accept)`
3. `ContentView` picks up the pending action and initiates the call

---

## 6. Call Overlay

The call UI overlays the entire app when a call is active:

### [Call Banner](../../Shared/ContentView.swift#L203)

When `ChatModel.activeCall != nil` and call is in connecting/active state:
- A banner appears at the top of ContentView (height: [`callTopPadding = 40`](../../Shared/ContentView.swift#L54))
- Shows contact name, call duration, tap to return to full-screen call
- Main content is padded down to accommodate the banner

### [Full-Screen Call View](../../Shared/ContentView.swift#L185)

When `ChatModel.showCallView == true`:
- `ActiveCallView` covers the entire screen as a ZStack overlay
- Contains local/remote video, controls (mute, camera, speaker, end)
- PiP mode: `ChatModel.activeCallViewIsCollapsed` collapses to mini view
- Call view is always rendered on top of navigation and sheets

```swift
// In ContentView.allViews():
ZStack {
    contentView()
        .padding(.top, showCallArea ? callTopPadding : 0)

    if showCallArea, let call = chatModel.activeCall {
        VStack {
            activeCallInteractiveArea(call)
            Spacer()
        }
    }

    if chatModel.showCallView, let call = chatModel.activeCall {
        callView(call)  // Full screen overlay
    }
}
```

---

## 7. Authentication Gate

### [Local Authentication](../../Shared/ContentView.swift#L359)

When [`DEFAULT_PERFORM_LA`](../../Shared/ContentView.swift#L44) is enabled:

1. App enters background: `chatModel.contentViewAccessAuthenticated = false`
2. App returns to foreground: `ContentView` shows [`lockButton()`](../../Shared/ContentView.swift#L238) instead of content
3. User taps lock button: [`LocalAuthView`](../../Shared/ContentView.swift#L95) presented
4. On successful auth: `chatModel.contentViewAccessAuthenticated = true`, content revealed

### Authentication Methods
- Face ID / Touch ID (via `LocalAuthentication` framework)
- Custom numeric passcode
- Custom alphanumeric passcode

### [Extended Authentication](../../Shared/ContentView.swift#L351)
- After successful auth, a grace period prevents re-auth for brief background/foreground cycles ([`unlockedRecently()`](../../Shared/ContentView.swift#L351))
- [`contentAccessAuthenticationExtended`](../../Shared/ContentView.swift#L35) is computed at `ContentView.init` to avoid render-time race conditions
- The `enteredBackgroundAuthenticated` timestamp tracks when the app was last authenticated in background

---

## 8. [Onboarding Flow](../../Shared/Views/Onboarding/OnboardingView.swift#L13)

First-launch experience controlled by [`ChatModel.onboardingStage`](../../Shared/Views/Onboarding/OnboardingView.swift#L46):

```swift
enum OnboardingStage: String, Identifiable {
    case step1_SimpleXInfo              // Welcome screen
    case step2_CreateProfile            // deprecated
    case step3_CreateSimpleXAddress     // deprecated
    case step3_ChooseServerOperators    // Choose server operators
    case step4_SetNotificationsMode     // Set notification preferences
    case onboardingComplete             // Normal operation
}
```

Each stage is a dedicated view presented in place of `ChatListView` within [`ContentView`](../../Shared/ContentView.swift#L174).

Migration state (`ChatModel.migrationState != nil`) takes precedence over onboarding.

---

## 9. Channel Creation Flow (`AddChannelView`)

**Source:** [`Shared/Views/NewChat/AddChannelView.swift`](../../Shared/Views/NewChat/AddChannelView.swift)

### Entry Point

`NewChatMenuButton` includes a NavigationLink "Create public channel" with antenna icon, navigating to `AddChannelView`.

### Three-Step Wizard

| Step | Function | Description |
|------|----------|-------------|
| 1. Profile | `profileStepView()` | Channel name input (`channelNameTextField()`), profile image picker. "Configure relays" link to `NetworkAndServers`. Validates via `canCreateProfile()` (non-empty + valid display name) and `checkHasRelays()`. |
| 2. Progress | `progressStepView(_:)` | Relay connection progress with `RelayProgressIndicator` (circular active/total or spinner). Expandable relay list with `relayStatusIndicator(_:)` (green/red/orange dots). Cancel via `cancelChannelCreation(_:)` which calls `apiDeleteChat`. |
| 3. Link | `linkStepView(_:)` | Wraps `GroupLinkView(isChannel: true)` for channel link sharing. |

### Key Functions

| Function | Scope | Description |
|----------|-------|-------------|
| `createChannel()` | private | Calls `apiNewPublicGroup(incognito:relayIds:groupProfile:)`, sets `ChannelRelaysModel` |
| `getEnabledRelays()` | private | Filters enabled/non-deleted relays, selects random 3 |
| `checkHasRelays()` | private | Validates at least one relay exists |
| `relayDisplayName(_:)` | module | name > domain > link host > fallback |
| `relayStatusIndicator(_:)` | module | Green/red/orange dot + status text |
| `RelayProgressIndicator` | module | Circular progress (active/total) or spinner |

## 10. Relay URL Interception

**Source:** [`Shared/ContentView.swift`](../../Shared/ContentView.swift#L454)

In `connectViaUrl_()`, relay address links (URL path `/r`) are intercepted before processing:

```swift
if path == "/r" {
    showAlert(NSLocalizedString("Relay address", ...),
              message: NSLocalizedString("This is a chat relay address, it cannot be used to connect.", ...))
    return
}
```

Similarly, in `planAndConnect()` (`NewChatView.swift`), `.simplexLink(_, .relay, _, _)` patterns trigger the same alert and block connection.

## 11. Channel-Specific NewChatView Behavior

**Source:** [`Shared/Views/NewChat/NewChatView.swift`](../../Shared/Views/NewChat/NewChatView.swift)

### Prepared Group Alert (`showPrepareGroupAlert`)

When `groupShortLinkInfo?.direct == false` (channel relay link), the prepare alert uses:
- Channel icon: `antenna.radiowaves.left.and.right.circle.fill`
- Title: "Open new channel"
- Error: "Error opening channel"
- `apiPrepareGroup` call passes `directLink: false`
- Stores `groupShortLinkInfo.groupRelays` in `ChatModel.shared.channelRelayHostnames`

### Own Link Confirmation (`showOwnGroupLinkConfirmConnectSheet`)

For channels: shows "This is your link for channel" with only "Open channel" + "Cancel" buttons. No incognito or profile selection options.

### Known Group Alert (`showOpenKnownGroupAlert`)

For channels (`groupInfo.useRelays`): titles become "Open channel" / "Open new channel".

---

## Source Files

| File | Path |
|------|------|
| Root view | [`Shared/ContentView.swift`](../../Shared/ContentView.swift) |
| App entry point | `Shared/SimpleXApp.swift` |
| Navigation compat | [`Shared/Views/Helpers/NavStackCompat.swift`](../../Shared/Views/Helpers/NavStackCompat.swift) |
| Chat list (nav root) | `Shared/Views/ChatList/ChatListView.swift` |
| Nav link wrapper | `Shared/Views/ChatList/ChatListNavLink.swift` |
| User picker | `Shared/Views/ChatList/UserPicker.swift` |
| New chat view | [`Shared/Views/NewChat/NewChatView.swift`](../../Shared/Views/NewChat/NewChatView.swift) |
| Channel creation | [`Shared/Views/NewChat/AddChannelView.swift`](../../Shared/Views/NewChat/AddChannelView.swift) |
| New chat menu | [`Shared/Views/NewChat/NewChatMenuButton.swift`](../../Shared/Views/NewChat/NewChatMenuButton.swift) |
| Settings view | [`Shared/Views/UserSettings/SettingsView.swift`](../../Shared/Views/UserSettings/SettingsView.swift) |
| User profiles | [`Shared/Views/UserSettings/UserProfilesView.swift`](../../Shared/Views/UserSettings/UserProfilesView.swift) |
| Onboarding view | [`Shared/Views/Onboarding/OnboardingView.swift`](../../Shared/Views/Onboarding/OnboardingView.swift) |
| Active call view | `Shared/Views/Call/ActiveCallView.swift` |
| Local auth view | `Shared/Views/LocalAuth/LocalAuthView.swift` |
| Notification manager | `Shared/Model/NtfManager.swift` |