feat: add PR Core settings page

includes/admin/class-pr-core-settings.php

@@ -0,0 +1,176 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Settings page for PR Core plugin features.
+ *
+ * What: Registers admin menu, renders settings form, and handles option saves
+ *       for features like Related Articles.
+ * Who calls it: PR_Core_Admin::register_hooks().
+ * Dependencies: None (reads/writes wp_options).
+ */
+class PR_Core_Settings {
+
+	/** @var string Option key: enable/disable related articles. */
+	private const ENABLED_OPTION = 'pr_core_related_posts_enabled';
+
+	/** @var string Option key: related articles limit (1-6). */
+	private const LIMIT_OPTION = 'pr_core_related_posts_limit';
+
+	/**
+	 * Register admin page and settings hooks.
+	 *
+	 * @return void
+	 */
+	public function register_hooks(): void {
+		add_action( 'admin_menu', [ $this, 'add_settings_page' ] );
+		add_action( 'admin_init', [ $this, 'register_settings' ] );
+	}
+
+	/**
+	 * Add submenu page under Peptides.
+	 *
+	 * @return void
+	 */
+	public function add_settings_page(): void {
+		add_submenu_page(
+			'edit.php?post_type=' . PR_Core_Peptide_CPT::POST_TYPE,
+			__( 'PR Core Settings', 'peptide-repo-core' ),
+			__( 'Settings', 'peptide-repo-core' ),
+			'manage_options',
+			'pr-core-settings',
+			[ $this, 'render_page' ]
+		);
+	}
+
+	/**
+	 * Register settings fields.
+	 *
+	 * @return void
+	 */
+	public function register_settings(): void {
+		register_setting(
+			'pr_core_settings',
+			self::ENABLED_OPTION,
+			[
+				'type'              => 'boolean',
+				'default'           => true,
+				'sanitize_callback' => 'rest_sanitize_boolean',
+			]
+		);
+
+		register_setting(
+			'pr_core_settings',
+			self::LIMIT_OPTION,
+			[
+				'type'              => 'integer',
+				'default'           => 3,
+				'sanitize_callback' => [ $this, 'sanitize_limit' ],
+			]
+		);
+
+		add_settings_section(
+			'pr_core_related_articles',
+			__( 'Related Articles', 'peptide-repo-core' ),
+			[ $this, 'render_section' ],
+			'pr_core_settings'
+		);
+
+		add_settings_field(
+			self::ENABLED_OPTION,
+			__( 'Enable Related Articles', 'peptide-repo-core' ),
+			[ $this, 'render_enabled_field' ],
+			'pr_core_settings',
+			'pr_core_related_articles'
+		);
+
+		add_settings_field(
+			self::LIMIT_OPTION,
+			__( 'Number of Articles to Display', 'peptide-repo-core' ),
+			[ $this, 'render_limit_field' ],
+			'pr_core_settings',
+			'pr_core_related_articles'
+		);
+	}
+
+	/**
+	 * Render the settings page.
+	 *
+	 * @return void
+	 */
+	public function render_page(): void {
+		?>
+		<div class="wrap">
+			<h1><?php esc_html_e( 'Peptide Repo Core Settings', 'peptide-repo-core' ); ?></h1>
+			<form method="post" action="options.php">
+				<?php
+				settings_fields( 'pr_core_settings' );
+				do_settings_sections( 'pr_core_settings' );
+				submit_button();
+				?>
+			</form>
+		</div>
+		<?php
+	}
+
+	/**
+	 * Render section description.
+	 *
+	 * @return void
+	 */
+	public function render_section(): void {
+		echo '<p>' . esc_html__( 'Configure the Related Articles section that appears on peptide single pages.', 'peptide-repo-core' ) . '</p>';
+	}
+
+	/**
+	 * Render enabled toggle field.
+	 *
+	 * @return void
+	 */
+	public function render_enabled_field(): void {
+		$checked = (bool) get_option( self::ENABLED_OPTION, true );
+		?>
+		<input
+			type="checkbox"
+			name="<?php echo esc_attr( self::ENABLED_OPTION ); ?>"
+			value="1"
+			<?php checked( $checked, true ); ?>
+		/>
+		<label>
+			<?php esc_html_e( 'Display related articles on peptide pages', 'peptide-repo-core' ); ?>
+		</label>
+		<?php
+	}
+
+	/**
+	 * Render limit field.
+	 *
+	 * @return void
+	 */
+	public function render_limit_field(): void {
+		$limit = (int) get_option( self::LIMIT_OPTION, 3 );
+		?>
+		<input
+			type="number"
+			name="<?php echo esc_attr( self::LIMIT_OPTION ); ?>"
+			value="<?php echo esc_attr( (string) $limit ); ?>"
+			min="1"
+			max="6"
+		/>
+		<p class="description">
+			<?php esc_html_e( 'Number of articles to display (1-6). Default: 3.', 'peptide-repo-core' ); ?>
+		</p>
+		<?php
+	}
+
+	/**
+	 * Sanitize limit to 1-6 range.
+	 *
+	 * @param mixed $value Raw input.
+	 * @return int Sanitized value.
+	 */
+	public function sanitize_limit( $value ): int {
+		$limit = (int) $value;
+		return min( 6, max( 1, $limit ) );
+	}
+}