Spry/demo/Pages/PageComponentsOverviewPage.vala

using Spry;
using Inversion;

/**
 * PageComponentsOverviewPage - Introduction to PageComponent
 * 
 * This page explains what PageComponents are, how they differ from regular
 * Components, and when to use them.
 */
public class PageComponentsOverviewPage : PageComponent {
    
    public override string title { get { return "Page Components - Spry"; } }
    
    public const string ROUTE = "/page-components/overview";
    
    private ComponentFactory factory = inject<ComponentFactory>();
    
    public override string markup { get {
        return """
        <div class="doc-content">
            <div class="doc-hero">
                <h1>Page Components</h1>
                <p class="doc-subtitle">Combine Component and Endpoint into a single powerful abstraction</p>
            </div>
            
            <section class="doc-section">
                <h2>What are Page Components?</h2>
                <p>
                    A <code>PageComponent</code> is a special type of component that acts as both a 
                    <strong>Component</strong> AND an <strong>Endpoint</strong>. This means it can render
                    HTML templates <em>and</em> handle HTTP requests at a specific route.
                </p>
                <p>
                    In traditional web frameworks, you often need separate classes for routes/endpoints
                    and for rendering views. PageComponent eliminates this duplication by combining
                    both responsibilities into a single cohesive class.
                </p>
            </section>
            
            <section class="doc-section">
                <h2>PageComponent vs Component</h2>
                <p>
                    Understanding when to use <code>PageComponent</code> vs <code>Component</code> is essential:
                </p>
                
                <table class="doc-table">
                    <thead>
                        <tr>
                            <th>Feature</th>
                            <th>Component</th>
                            <th>PageComponent</th>
                        </tr>
                    </thead>
                    <tbody>
                        <tr>
                            <td>Has markup</td>
                            <td>✓ Yes</td>
                            <td>✓ Yes</td>
                        </tr>
                        <tr>
                            <td>Handles HTTP routes</td>
                            <td>✗ No</td>
                            <td>✓ Yes</td>
                        </tr>
                        <tr>
                            <td>Can be nested in outlets</td>
                            <td>✓ Yes</td>
                            <td>✗ No (top-level only)</td>
                        </tr>
                        <tr>
                            <td>Implements Endpoint</td>
                            <td>✗ No</td>
                            <td>✓ Yes</td>
                        </tr>
                        <tr>
                            <td>Wrapped by templates</td>
                            <td>✗ No</td>
                            <td>✓ Yes</td>
                        </tr>
                    </tbody>
                </table>
            </section>
            
            <section class="doc-section">
                <h2>When to Use Each</h2>
                
                <div class="feature-grid">
                    <div class="feature-card">
                        <h3>Use PageComponent when:</h3>
                        <ul>
                            <li>Creating top-level pages (routes)</li>
                            <li>Building documentation pages</li>
                            <li>Rendering full HTML documents</li>
                            <li>The component needs its own URL</li>
                        </ul>
                    </div>
                    <div class="feature-card">
                        <h3>Use Component when:</h3>
                        <ul>
                            <li>Building reusable UI elements</li>
                            <li>Creating widgets or cards</li>
                            <li>Nesting inside other components</li>
                            <li>Rendering partial content</li>
                        </ul>
                    </div>
                </div>
            </section>
            
            <section class="doc-section">
                <h2>Basic PageComponent Example</h2>
                <p>
                    Here's how to create a simple PageComponent:
                </p>
                
                <spry-component name="CodeBlockComponent" sid="basic-example"/>
            </section>
            
            <section class="doc-section">
                <h2>Route Registration</h2>
                <p>
                    PageComponents are registered as endpoints in your application's Main.vala.
                    You register both the component type and its route:
                </p>
                
                <spry-component name="CodeBlockComponent" sid="route-registration"/>
            </section>
            
            <section class="doc-section">
                <h2>Dependency Injection in Pages</h2>
                <p>
                    PageComponents support the same dependency injection patterns as regular components.
                    Use <code>inject<T>()</code> to access services, stores, and factories:
                </p>
                
                <spry-component name="CodeBlockComponent" sid="di-example"/>
            </section>
            
            <section class="doc-section">
                <h2>Template Wrapping</h2>
                <p>
                    One of the most powerful features of PageComponents is automatic template wrapping.
                    When a PageComponent renders, it is automatically wrapped by matching 
                    <code>PageTemplate</code> instances.
                </p>
                <p>
                    This means your PageComponent markup only needs to contain the <em>content</em>
                    of the page, not the full HTML document structure. The template provides the
                    <code><html></code>, <code><head></code>, <code><body></code>,
                    navigation, and footer.
                </p>
                
                <div class="info-box">
                    <p>
                        <strong>💡 Tip:</strong> Learn more about templates in the 
                        <a href="/page-components/templates">Page Templates</a> documentation.
                    </p>
                </div>
            </section>
            
            <section class="doc-section">
                <h2>How handle_request() Works</h2>
                <p>
                    The <code>PageComponent</code> base class implements the <code>Endpoint</code>
                    interface's <code>handle_request()</code> method. This method:
                </p>
                
                <ol class="doc-list">
                    <li>Collects all matching <code>PageTemplate</code> instances sorted by prefix depth</li>
                    <li>Renders each template in order</li>
                    <li>Finds <code>&lt;spry-content/&gt;</code> elements in each template</li>
                    <li>Nests the content into the outlet, building the complete document</li>
                    <li>Returns the final HTML as an <code>HttpResult</code></li>
                </ol>
                
                <p>
                    You typically don't need to override <code>handle_request()</code> - the default
                    implementation handles everything for you.
                </p>
            </section>
            
            <section class="doc-section">
                <h2>Next Steps</h2>
                <div class="nav-cards">
                    <a href="/page-components/templates" class="nav-card">
                        <h3>Page Templates →</h3>
                        <p>Learn how to create layout templates that wrap your pages</p>
                    </a>
                    <a href="/components/overview" class="nav-card">
                        <h3>Components Overview →</h3>
                        <p>Review the basics of Spry components</p>
                    </a>
                </div>
            </section>
        </div>
        """;
    }}
    
    public override async void prepare() throws Error {
        // Basic PageComponent example
        var basic_example = get_component_child<CodeBlockComponent>("basic-example");
        basic_example.language = "vala";
        basic_example.code = "using Spry;\n" +
            "using Inversion;\n\n" +
            "public class DocumentationPage : PageComponent {\n" +
            "    \n" +
            "    // Dependency injection works the same as Component\n" +
            "    private ComponentFactory factory = inject<ComponentFactory>();\n" +
            "    \n" +
            "    public override string markup { get {\n" +
            "        return \"\"\"\n" +
            "        <div class=\"page-content\">\n" +
            "            <h1>My Documentation Page</h1>\n" +
            "            <p>This page handles its own route.</p>\n" +
            "        </div>\n" +
            "        \"\"\";\n" +
            "    }}\n" +
            "    \n" +
            "    public override async void prepare() throws Error {\n" +
            "        // Set up page content\n" +
            "    }\n" +
            "}";
        
        // Route registration example
        var route_reg = get_component_child<CodeBlockComponent>("route-registration");
        route_reg.language = "vala";
        route_reg.code = "// In Main.vala:\n\n" +
            "// Register the page component with the dependency container\n" +
            "application.add_transient<DocumentationPage>();\n\n" +
            "// Register the page as an endpoint at a specific route\n" +
            "application.add_endpoint<DocumentationPage>(\n" +
            "    new EndpointRoute(\"/docs/page\")\n" +
            ");\n\n" +
            "// Now visiting /docs/page will render DocumentationPage\n" +
            "// automatically wrapped by any matching PageTemplate";
        
        // Dependency injection example
        var di_example = get_component_child<CodeBlockComponent>("di-example");
        di_example.language = "vala";
        di_example.code = "public class UserProfilePage : PageComponent {\n" +
            "    \n" +
            "    // Inject services you need\n" +
            "    private ComponentFactory factory = inject<ComponentFactory>();\n" +
            "    private UserStore user_store = inject<UserStore>();\n" +
            "    private HttpContext http_context = inject<HttpContext>();\n" +
            "    \n" +
            "    public override string markup { get {\n" +
            "        return \"\"\"\n" +
            "        <div class=\"profile-page\">\n" +
            "            <h2 sid=\"username\"></h2>\n" +
            "            <p sid=\"email\"></p>\n" +
            "        </div>\n" +
            "        \"\"\";\n" +
            "    }}\n" +
            "    \n" +
            "    public override async void prepare() throws Error {\n" +
            "        // Access route parameters from http_context\n" +
            "        var user_id = http_context.request.query_params\n" +
            "            .get_any_or_default(\"id\", \"guest\");\n" +
            "        \n" +
            "        // Use injected store to fetch data\n" +
            "        var user = yield user_store.get_user(user_id);\n" +
            "        \n" +
            "        // Populate template\n" +
            "        this[\"username\"].text_content = user.name;\n" +
            "        this[\"email\"].text_content = user.email;\n" +
            "    }\n" +
            "}";
    }
}