PRIMARY_SECONDARY_NAV_BREADCRUMBS(3)  RSX Framework Manual  PRIMARY_SECONDARY_NAV_BREADCRUMBS(3)

NAME
    Primary, Secondary Navigation and Breadcrumbs - SPA navigation systems

SYNOPSIS
    // Primary navigation (sidebar) in layout
    class Frontend_Spa_Layout extends Spa_Layout {
        on_create() {
            this.state = {
                nav_sections: [
                    { title: 'Overview', items: [
                        { label: 'Dashboard', icon: 'bi-house', href: Rsx.Route('...') }
                    ]}
                ]
            };
        }
    }

    // Secondary navigation (sublayout sidebar)
    class Settings_Layout extends Spa_Layout {
        static ACTION_CONFIG = {
            'Settings_General_Action': { icon: 'bi-gear', label: 'General' },
            'Settings_Profile_Action': { icon: 'bi-person', label: 'Profile' }
        };
    }

    // Breadcrumb methods in actions
    class Contacts_View_Action extends Spa_Action {
        async page_title() { return this.data.contact.name; }
        async breadcrumb_label() { return this.data.contact.name; }
        async breadcrumb_label_active() { return 'View Contact'; }
        async breadcrumb_parent() { return Rsx.Route('Contacts_Index_Action'); }
    }

DESCRIPTION
    RSX provides a comprehensive navigation system for SPAs consisting of:

    1. Primary Navigation - Main sidebar with sections and links
    2. Secondary Navigation - Sublayout sidebars for feature areas
    3. Breadcrumbs - Progressive URL-based navigation trail

    The system uses session storage caching for instant navigation feedback
    while resolving live data in the background.

PRIMARY NAVIGATION
    The primary navigation is typically a sidebar defined in the main SPA
    layout (e.g., Frontend_Spa_Layout). It uses the Sidebar_Nav component.

    Layout Structure:
        // Frontend_Spa_Layout.js
        class Frontend_Spa_Layout extends Spa_Layout {
            on_create() {
                this.state = {
                    nav_sections: [
                        {
                            title: 'Overview',
                            items: [
                                {
                                    label: 'Dashboard',
                                    icon: 'bi-house-door',
                                    href: Rsx.Route('Dashboard_Index_Action'),
                                },
                                {
                                    label: 'Calendar',
                                    icon: 'bi-calendar',
                                    href: Rsx.Route('Calendar_Index_Action'),
                                },
                            ],
                        },
                        {
                            title: 'Business',
                            items: [
                                { label: 'Clients', icon: 'bi-people',
                                  href: Rsx.Route('Clients_Index_Action') },
                                { label: 'Contacts', icon: 'bi-person-rolodex',
                                  href: Rsx.Route('Contacts_Index_Action') },
                            ],
                        },
                    ],
                };
            }

            on_action(url, action_name, args) {
                // Update active state on navigation
                this.sid('sidebar_nav').on_action(url, action_name, args);
            }
        }

    Template Structure:
        <Define:Frontend_Spa_Layout>
            <nav class="app-sidebar">
                <Sidebar_Nav $sid="sidebar_nav"
                    $sections=this.state.nav_sections />
            </nav>
            <main $sid="content"></main>
        </Define:Frontend_Spa_Layout>

    Sidebar_Nav Component:
        Renders navigation sections with automatic active state based on
        current URL. Supports icons (Bootstrap Icons), labels, and href.

        on_action(url, action_name, args):
            Called by layout to update active link highlighting.
            Matches current URL to nav item hrefs.

SECONDARY NAVIGATION (SUBLAYOUTS)
    Secondary navigation is used for feature areas with multiple related
    pages (e.g., Settings). Implemented as sublayouts with their own sidebar.

    Sublayout Pattern:
        // Settings_Layout.js
        class Settings_Layout extends Spa_Layout {
            // Configure nav items per action
            static ACTION_CONFIG = {
                'Settings_General_Action': {
                    icon: 'bi-gear',
                    label: 'General Settings'
                },
                'Settings_Profile_Action': {
                    icon: 'bi-person',
                    label: 'Profile'
                },
                'Settings_User_Management_Index_Action': {
                    icon: 'bi-people',
                    label: 'User Management'
                },
            };

            on_create() {
                this._build_nav_items();
            }

            _build_nav_items() {
                this.state.nav_items = [];
                for (const [action_name, config] of
                     Object.entries(Settings_Layout.ACTION_CONFIG)) {
                    this.state.nav_items.push({
                        action: action_name,
                        icon: config.icon,
                        label: config.label,
                        href: Rsx.Route(action_name),
                    });
                }
            }

            on_action(url, action_name, args) {
                this._update_active_nav(action_name);
            }

            _update_active_nav(action_name) {
                this.$sid('nav').find('.active').removeClass('active');
                this.$sid('nav')
                    .find(`[data-action="${action_name}"]`)
                    .addClass('active');
            }
        }

    Template Structure:
        <Define:Settings_Layout>
            <div class="settings-layout">
                <aside class="settings-sidebar">
                    <nav $sid="nav">
                        <% for (let item of this.state.nav_items) { %>
                            <a href="<%= item.href %>"
                               data-action="<%= item.action %>"
                               class="settings-sidebar__item">
                                <i class="bi <%= item.icon %>"></i>
                                <span><%= item.label %></span>
                            </a>
                        <% } %>
                    </nav>
                </aside>
                <div class="settings-content" $sid="content"></div>
            </div>
        </Define:Settings_Layout>

    Action Declaration:
        Actions declare both outer and inner layouts:

        @route('/frontend/settings/general')
        @layout('Frontend_Spa_Layout')     // Outer layout
        @layout('Settings_Layout')          // Sublayout (nested)
        @spa('Frontend_Spa_Controller::index')
        class Settings_General_Action extends Spa_Action { }

BREADCRUMB SYSTEM
    Breadcrumbs provide hierarchical navigation context. The system uses
    progressive resolution with caching for instant display.

    Action Breadcrumb Methods:
        All methods are async and can await the 'load' event if needed.

        page_title()
            Returns the page title for the header and document.title.
            Example: "Edit: John Smith"

        breadcrumb_label()
            Returns the label when this page appears as a PARENT in
            another page's breadcrumb trail.
            Example: "John Smith" (when viewing edit page)

        breadcrumb_label_active()
            Returns the label when this page is the CURRENT page
            (rightmost breadcrumb, no link).
            Example: "Edit Contact"

        breadcrumb_parent()
            Returns the URL of the parent page, or null for root.
            Example: Rsx.Route('Contacts_View_Action', { id: this.args.id })

    Example Implementation:
        class Contacts_View_Action extends Spa_Action {
            on_create() {
                this.data.contact = { first_name: '', last_name: '' };
            }

            async on_load() {
                this.data.contact = await Contact_Model.fetch(this.args.id);
            }

            // Helper to await loaded data
            async _await_loaded() {
                if (this.data.contact && this.data.contact.id) return;
                await new Promise(resolve => this.on('load', resolve));
            }

            async page_title() {
                await this._await_loaded();
                const c = this.data.contact;
                return `${c.first_name} ${c.last_name}`.trim() || 'Contact';
            }

            async breadcrumb_label() {
                await this._await_loaded();
                const c = this.data.contact;
                return `${c.first_name} ${c.last_name}`.trim() || 'Contact';
            }

            async breadcrumb_label_active() {
                return 'View Contact';  // Static, no await needed
            }

            async breadcrumb_parent() {
                return Rsx.Route('Contacts_Index_Action');  // Static route
            }
        }

    Awaiting Loaded Data:
        Breadcrumb methods are called BEFORE on_load() completes. If a method
        needs loaded data (e.g., contact name), it must await the 'load' event:

            async _await_loaded() {
                // Check if data is already loaded
                if (this.data.contact && this.data.contact.id) return;
                // Otherwise wait for 'load' event
                await new Promise(resolve => this.on('load', resolve));
            }

        The 'load' event fires immediately if already past that lifecycle
        phase, so this pattern is safe to call multiple times.

RSX_BREADCRUMB_RESOLVER
    Framework class that handles breadcrumb resolution with caching.

    Location: /system/app/RSpade/Breadcrumbs/Rsx_Breadcrumb_Resolver.js

    API:
        Rsx_Breadcrumb_Resolver.stream(action, url, callbacks)
            Streams breadcrumb data progressively.

            Parameters:
                action    - Current Spa_Action instance
                url       - Current URL (pathname + search)
                callbacks - Object with callback functions:
                    on_chain(chain)           - Chain structure ready
                    on_label_update(idx, lbl) - Individual label resolved
                    on_complete(chain)        - All labels resolved

            Returns: Cancel function

        Rsx_Breadcrumb_Resolver.clear_cache(url)
            Clears cached breadcrumb chain for a URL.

    Resolution Flow:
        1. Check session cache for URL's breadcrumb chain
        2. If cached, display immediately
        3. Walk breadcrumb_parent() chain to get structure (URLs)
        4. Compare to cache:
           - Different length: render skeleton with blank labels
           - Same length: render with cached labels
        5. Resolve each label via breadcrumb_label()/breadcrumb_label_active()
        6. Update display as each label resolves
        7. Cache final result

    Caching:
        Uses Rsx_Storage.session_set/get() with key prefix 'breadcrumb_chain:'
        Cached data: Array of { url, label, is_active }

LAYOUT INTEGRATION
    The layout handles header rendering and breadcrumb streaming.

    Frontend_Spa_Layout Integration:
        class Frontend_Spa_Layout extends Spa_Layout {
            static TITLE_CACHE_PREFIX = 'header_text:';

            on_action(url, action_name, args) {
                // Update page title with caching
                this._update_page_title(url);

                // Cancel previous breadcrumb stream
                if (this._breadcrumb_cancel) {
                    this._breadcrumb_cancel();
                }

                // Start new breadcrumb stream
                this._breadcrumb_cancel = Rsx_Breadcrumb_Resolver.stream(
                    this.action,
                    url,
                    {
                        on_chain: (chain) => this._on_breadcrumb_chain(chain),
                        on_label_update: (i, l) => this._on_breadcrumb_label_update(i, l),
                        on_complete: (chain) => this._on_breadcrumb_complete(chain)
                    }
                );
            }

            async _update_page_title(url) {
                const $title = this.$sid('page_title');
                const cache_key = Frontend_Spa_Layout.TITLE_CACHE_PREFIX + url;

                // Clear, show cached, then resolve live
                $title.html('&nbsp;');
                const cached = Rsx_Storage.session_get(cache_key);
                if (cached) {
                    $title.html(cached);
                    document.title = 'RSX - ' + cached;
                }

                const live = await this.action.page_title();
                if (live) {
                    $title.html(live);
                    document.title = 'RSX - ' + live;
                    Rsx_Storage.session_set(cache_key, live);
                }
            }
        }

BREADCRUMB_NAV COMPONENT
    Renders the breadcrumb trail from a chain array.

    Location: /rsx/theme/components/page/breadcrumb_nav.jqhtml

    Props:
        $crumbs - Array of { label, url, is_active, resolved }
                  label: string or null (shows placeholder if null)
                  url: string or null (no link if null or is_active)
                  is_active: boolean (current page, no link)
                  resolved: boolean (false shows loading state)

    Usage:
        $breadcrumbs.component('Breadcrumb_Nav', {
            crumbs: [
                { label: 'Contacts', url: '/contacts', is_active: false },
                { label: 'John Smith', url: '/contacts/view/1', is_active: false },
                { label: 'Edit Contact', url: null, is_active: true }
            ]
        });

PAGE HEADER STRUCTURE
    Standard page header with title, breadcrumbs, and action buttons.

    Template Pattern:
        <header class="page-title-header">
            <div class="d-flex justify-content-between align-items-start">
                <div>
                    <h1 $sid="page_title"></h1>
                    <nav $sid="page_breadcrumbs"></nav>
                </div>
                <div $sid="page_actions"></div>
            </div>
        </header>

    Action Buttons:
        Actions define page_actions() to provide header buttons:

        class Contacts_View_Action extends Spa_Action {
            page_actions() {
                return `
                    <div class="d-flex gap-2">
                        <a href="${Rsx.Route('Contacts_Index_Action')}"
                           class="btn btn-secondary btn-sm">
                            <i class="bi bi-arrow-left"></i> Back
                        </a>
                        <a href="${Rsx.Route('Contacts_Edit_Action', this.args.id)}"
                           class="btn btn-primary btn-sm">
                            <i class="bi bi-pencil"></i> Edit
                        </a>
                    </div>
                `;
            }
        }

        The layout renders these via _render_page_actions().

BREADCRUMB CHAIN EXAMPLE
    For URL /contacts/edit/1, the breadcrumb chain resolves as:

    Chain Structure (URLs):
        1. /contacts          (Contacts_Index_Action)
        2. /contacts/view/1   (Contacts_View_Action)
        3. /contacts/edit/1   (Contacts_Edit_Action) - ACTIVE

    Resolution Process:
        1. Contacts_Edit_Action.breadcrumb_parent() -> /contacts/view/1
        2. Load detached Contacts_View_Action
        3. Contacts_View_Action.breadcrumb_parent() -> /contacts
        4. Load detached Contacts_Index_Action
        5. Contacts_Index_Action.breadcrumb_parent() -> null (root)

    Label Resolution (parallel):
        - Index: breadcrumb_label() -> "Contacts"
        - View: breadcrumb_label() -> "John Smith" (awaits load)
        - Edit: breadcrumb_label_active() -> "Edit Contact"

    Final Display:
        Contacts > John Smith > Edit Contact

CACHING STRATEGY
    Two caches are used for instant navigation feedback:

    Page Title Cache:
        Key: 'header_text:/contacts/edit/1'
        Value: "Edit: John Smith"

    Breadcrumb Chain Cache:
        Key: 'breadcrumb_chain:/contacts/edit/1'
        Value: [
            { url: '/contacts', label: 'Contacts', is_active: false },
            { url: '/contacts/view/1', label: 'John Smith', is_active: false },
            { url: '/contacts/edit/1', label: 'Edit Contact', is_active: true }
        ]

    Cache Behavior:
        - Cached values display immediately on navigation
        - Live values resolve in background
        - Cache updates when live values complete
        - Previous breadcrumbs stay visible until new chain ready

FILES
    /system/app/RSpade/Breadcrumbs/Rsx_Breadcrumb_Resolver.js
        Breadcrumb resolution with progressive streaming and caching

    /rsx/app/frontend/Frontend_Spa_Layout.js
        Main layout with navigation and header integration

    /rsx/theme/components/page/breadcrumb_nav.jqhtml
        Breadcrumb rendering component

    /rsx/theme/components/nav/sidebar_nav.jqhtml
        Primary sidebar navigation component

SEE ALSO
    spa(3), jqhtml(3), storage(3)

RSX Framework                    2025-12-16       PRIMARY_SECONDARY_NAV_BREADCRUMBS(3)