Add about dialog configuration struct

Sources/Adwaita/Model/AdwaitaAboutDialogConfig.swift

@@ -0,0 +1,136 @@
+//
+//  AdwaitaAboutDialogConfig.swift
+//  Adwaita
+//
+//  Created by lambdaclan on 09.01.2026.
+//
+
+import CAdw
+import Foundation
+
+/// Initialization options for the about dialog wrapper.
+public struct AdwaitaAboutDialogConfig {
+
+    /// Example HTML release notes used for demonstrating how the About dialog
+    /// renders structured content such as paragraphs, lists, and inline markup.
+    /// This sample is intended for testing, previews, and documentation.
+    public static let demoReleaseNotes = """
+        <p>This template supports three structures: paragraphs using <code>&lt;p&gt;</code>, ordered lists using
+        <code>&lt;ol&gt;</code>, and unordered lists using <code>&lt;ul&gt;</code>.
+        Both list types must contain list items marked with <code>&lt;li&gt;</code>.</p>
+        <p>Within paragraphs and list items, you may use <code>&lt;em&gt;</code> to apply
+        <em>emphasis</em>(italic text) and <code>&lt;code&gt;</code> to mark <code>inline code</code>
+        for monospaced text.
+        These inline styles are supported only inside those elements.</p>
+        <p>Any text placed outside <code>&lt;p&gt;</code>, <code>&lt;ol&gt;</code>,
+        <code>&lt;ul&gt;</code>, or <code>&lt;li&gt;</code> tags is ignored by the template
+        processor.</p>
+        <ol>
+        <li>Ordered list items represent numbered content and may
+        include <code>&lt;em&gt;</code> for <em>emphasis</em> or <code>&lt;code&gt;</code> for inline code.</li>
+            <li>They follow the same rules as paragraphs regarding allowed inline styles.</li>
+        </ol>
+        <ul>
+        <li>Unordered list items represent bullet points and support the same inline styles.</li>
+        <li>They must contain only text and allowed inline formatting.</li>
+        </ul>
+        """
+
+    /// Example Pango‑markup comments showcasing how styled text, links, and
+    /// formatting behave inside the About dialog’s “Details” section.
+    /// Useful for previews, testing, and as a reference for developers who want
+    /// to embed formatted text in their own dialogs.
+    public static let demoComments = """
+        This text demonstrates basic Pango markup along with helpful documentation links.
+
+        Comments shown in an Adwaita AboutDialog will appear on the Details page.
+        They can be long and detailed, and they may include links and Pango markup for
+        formatting.
+
+        Pango markup supports tags like:
+        • <b>bold</b>
+        • <i>italic</i>
+        • <span foreground="steelblue">colored text</span>
+
+        Full reference: <a href="https://docs.gtk.org/Pango/pango_markup.html">Pango Markup
+        Reference</a>
+
+        Example markup:
+            <span font="14pt" weight="bold">Demo Title</span>
+            <span foreground="tomato">Highlighted text</span>
+            <u>Underlined text</u>
+
+        Useful links:
+        • <a href="https://adwaita-swift.aparoksha.dev/documentation/adwaita">Adwaita‑Swift Documentation</a>
+
+        You can embed these links directly in your UI using Pango markup.
+        """
+
+    /// The app's name.
+    public var appName: String?
+    /// The developer's name.
+    public var developer: String?
+    /// The app version.
+    public var version: String?
+    /// The app icon.
+    public var icon: Icon?
+    /// The app's website.
+    public var website: URL?
+    /// The link for opening issues.
+    public var issues: URL?
+    /// The app's release notes
+    public var releaseNotes: String?
+    /// The comments about the application
+    public var comments: String?
+
+    /// Initialize the about dialog wrapper.
+    /// - Parameters:
+    ///     - appName: The app's name.
+    ///     - developer: The developer's name.
+    ///     - version: The version string.
+    ///     - icon: The app icon.
+    ///     - website: The app's website.
+    ///     - issues: Website for reporting issues.
+    ///     - releaseNotes: The app's release notes.
+    ///     - comments: The comments about the application.
+    public init(
+        appName: String? = nil,
+        developer: String? = nil,
+        version: String? = nil,
+        icon: Icon? = nil,
+        website: URL? = nil,
+        issues: URL? = nil,
+        releaseNotes: String? = nil,
+        comments: String? = nil
+    ) {
+        self.appName = appName
+        self.developer = developer
+        self.version = version
+        self.icon = icon
+        self.website = website
+        self.issues = issues
+        self.releaseNotes = releaseNotes
+        self.comments = comments
+    }
+
+    /// Apply the configuration values to the given dialog.
+    /// - Parameters:
+    ///     - dialog: The underlying Adwaita dialog instance to update with the configuration.
+    func apply(to dialog: OpaquePointer) {
+        let handlers: [(String?, (OpaquePointer, UnsafePointer<CChar>?) -> Void)] = [
+            (appName, adw_about_dialog_set_application_name),
+            (developer, adw_about_dialog_set_developer_name),
+            (version, adw_about_dialog_set_version),
+            (icon?.string, adw_about_dialog_set_application_icon),
+            (website?.absoluteString, adw_about_dialog_set_website),
+            (issues?.absoluteString, adw_about_dialog_set_issue_url),
+            (releaseNotes, adw_about_dialog_set_release_notes),
+            (comments, adw_about_dialog_set_comments)
+        ]
+
+        for (value, action) in handlers {
+            value.map { action(dialog, $0) }
+        }
+    }
+
+}