<?php
/**
 * The Answer Density admin screen.
 *
 * @package PressRoost\AIVE
 */

namespace PressRoost\AIVE\Admin;

use PressRoost\AIVE\AnswerDensity\AnswerDensityParser;
use PressRoost\AIVE\Data\AnswerDensityStore;
use PressRoost\AIVE\Modules\AnswerDensity;
use PressRoost\AIVE\Utils\Helpers;

/**
 * Reports per-post answer density and drives single and bulk scans.
 *
 * Every number on this screen comes from the stored `aive_answer_density`
 * table or from a value this request computed from it; nothing stored post
 * content, a parse diagnostic or a PHP error ever reaches the page. A scan
 * error is reported as a fixed-vocabulary state - "Error" - never as the
 * underlying diagnostic code or anything libxml or PHP said.
 *
 * The screen itself is a read-only GET: pagination and the type filter take
 * their input from `$_GET` the way CrawlerLogPage's sort and filter do, with
 * no nonce, because nothing here changes state. The two actions that do
 * change state - a single scan and the bulk "Scan All Published Content" run
 * - are AJAX requests gated behind {@see AnswerDensity::NONCE_ACTION} and
 * `manage_options`, handled by a small script this page is the only one to
 * enqueue.
 *
 * @since 1.5.0
 */
final class AnswerDensityPage {

	/**
	 * Admin page slug.
	 *
	 * @since 1.5.0
	 * @var string
	 */
	public const PAGE_SLUG = 'aive-answer-density';

	/**
	 * Rows per page in the listing table.
	 *
	 * @since 1.5.0
	 * @var int
	 */
	public const PER_PAGE = 20;

	/**
	 * Script handle for the bulk-scan progress script.
	 *
	 * @since 1.5.0
	 * @var string
	 */
	public const SCRIPT_HANDLE = 'aive-answer-density-admin';

	/**
	 * Database access for the answer density table.
	 *
	 * @since 1.5.0
	 * @var AnswerDensityStore
	 */
	private $store;

	/**
	 * Constructor.
	 *
	 * @since 1.5.0
	 *
	 * @param AnswerDensityStore $store Database access for the answer density table.
	 */
	public function __construct( AnswerDensityStore $store ) {
		$this->store = $store;
	}

	/**
	 * Enqueues the bulk-scan progress script, on this screen only.
	 *
	 * @since 1.5.0
	 *
	 * @return void
	 */
	public function enqueue_assets() {
		wp_enqueue_script(
			self::SCRIPT_HANDLE,
			AIVE_PLUGIN_URL . 'assets/js/answer-density-admin.js',
			array(),
			AIVE_VERSION,
			true
		);

		wp_localize_script(
			self::SCRIPT_HANDLE,
			'aiveAnswerDensity',
			array(
				'ajaxUrl'    => admin_url( 'admin-ajax.php' ),
				'nonce'      => wp_create_nonce( AnswerDensity::NONCE_ACTION ),
				'scanAction' => AnswerDensity::AJAX_SCAN,
				'bulkAction' => AnswerDensity::AJAX_BULK,
				'i18n'       => array(
					'starting'       => __( 'Starting…', 'summitcite' ),
					'scanning'       => __( 'Scanning…', 'summitcite' ),
					/* translators: 1: number processed, 2: total number of items. */
					'progress'       => __( 'Scanned %1$d of %2$d.', 'summitcite' ),
					'done'           => __( 'Scan complete. Reloading…', 'summitcite' ),
					'error'          => __( 'The scan could not continue. Reload the page and try again.', 'summitcite' ),
					'scanOne'        => __( 'Scan', 'summitcite' ),
					'scanOneBusy'    => __( 'Scanning…', 'summitcite' ),
					'scanOneDone'    => __( 'Scanned.', 'summitcite' ),
					'scanOneError'   => __( 'Could not scan this item.', 'summitcite' ),
					/* translators: 1: coverage ratio, two decimal places. 2: coverage points, one decimal place. 3: quality points, one decimal place. 4: structure points, one decimal place. 5: algorithm version number. */
					'scoreBreakdown' => __( 'Coverage %1$s (%2$s pts) · Quality %3$s pts · Structure %4$s pts · Algorithm v%5$d', 'summitcite' ),
				),
			)
		);
	}

	/**
	 * Renders the screen.
	 *
	 * The capability check is repeated here because a page callback is reachable
	 * by URL independently of the menu that registered it.
	 *
	 * @since 1.5.0
	 *
	 * @return void
	 */
	public function render() {
		if ( ! current_user_can( Admin::CAPABILITY ) ) {
			wp_die(
				esc_html__( 'You do not have permission to view the SummitCite answer density screen.', 'summitcite' ),
				'',
				array( 'response' => 403 )
			);
		}

		$enabled = Helpers::is_module_enabled( AnswerDensity::SLUG );
		$types   = $enabled ? AnswerDensity::configured_post_types() : array();

		?>
		<div class="wrap">
			<h1><?php echo esc_html__( 'Answer Density', 'summitcite' ); ?></h1>
			<?php $this->render_intro(); ?>
			<?php if ( ! $enabled ) : ?>
				<?php $this->render_disabled_notice(); ?>
			<?php elseif ( array() === $types ) : ?>
				<?php $this->render_no_types_notice(); ?>
			<?php else : ?>
				<?php
				$this->render_summary( $types );
				$this->render_scan_all( $types );
				$this->render_table( $types );
				?>
			<?php endif; ?>
		</div>
		<?php
	}

	/**
	 * Renders the standing explanation of what this feature does and does not
	 * measure.
	 *
	 * @since 1.5.0
	 *
	 * @return void
	 */
	private function render_intro() {
		printf(
			'<p>%s</p>',
			esc_html__(
				'Answer Density measures how much of a published item\'s heading structure reads as a question, and how much of that is answered immediately rather than buried further down. It is a deterministic, local heuristic about structure only.',
				'summitcite'
			)
		);

		printf(
			'<p>%s</p>',
			esc_html__(
				'A score says nothing about whether an answer is factually correct, complete or well written, does not predict how any AI system will treat the page, and is not a ranking or citation guarantee.',
				'summitcite'
			)
		);
	}

	/**
	 * Renders the disabled-module notice. No score table follows it.
	 *
	 * @since 1.5.0
	 *
	 * @return void
	 */
	private function render_disabled_notice() {
		printf(
			'<div class="notice notice-warning"><p><strong>%1$s</strong> %2$s <a href="%3$s">%4$s</a></p></div>',
			esc_html__( 'Switched off:', 'summitcite' ),
			esc_html__( 'Answer Density is disabled, so no scan runs and no score is shown. Stored results from before it was switched off are kept.', 'summitcite' ),
			esc_url( admin_url( 'admin.php?page=' . Settings::PAGE_SLUG . '#' . Settings::SECTION_ANSWER_DENSITY ) ),
			esc_html__( 'Open Answer Density settings', 'summitcite' )
		);
	}

	/**
	 * Renders the notice shown when no post type is configured at all.
	 *
	 * @since 1.5.0
	 *
	 * @return void
	 */
	private function render_no_types_notice() {
		printf(
			'<div class="notice notice-warning"><p><strong>%1$s</strong> %2$s <a href="%3$s">%4$s</a></p></div>',
			esc_html__( 'Nothing configured:', 'summitcite' ),
			esc_html__( 'No post type is currently configured for scoring, so there is nothing to scan or list.', 'summitcite' ),
			esc_url( admin_url( 'admin.php?page=' . Settings::PAGE_SLUG . '#' . Settings::SECTION_ANSWER_DENSITY ) ),
			esc_html__( 'Choose post types', 'summitcite' )
		);
	}

	/**
	 * Renders the average score, scanned count and per-type breakdown.
	 *
	 * @since 1.5.0
	 *
	 * @param array<int, string> $types Currently configured and allowed post types.
	 * @return void
	 */
	private function render_summary( array $types ) {
		$summary = $this->store->summary( $types );

		if ( null === $summary ) {
			printf(
				'<p role="status" class="notice notice-error inline">%s</p>',
				esc_html__( 'The summary could not be loaded.', 'summitcite' )
			);

			return;
		}

		?>
		<h2><?php echo esc_html__( 'Summary', 'summitcite' ); ?></h2>
		<table class="widefat striped" style="max-width:40em;">
			<caption class="screen-reader-text"><?php echo esc_html__( 'Answer density summary', 'summitcite' ); ?></caption>
			<tbody>
				<tr>
					<th scope="row"><?php echo esc_html__( 'Average score', 'summitcite' ); ?></th>
					<td>
						<?php
						if ( null === $summary['average_score'] ) {
							echo esc_html__( 'No scored content yet', 'summitcite' );
						} else {
							printf(
								/* translators: %s: average score, one decimal place. */
								esc_html__( '%s / 100', 'summitcite' ),
								esc_html( number_format_i18n( $summary['average_score'], 1 ) )
							);
						}
						?>
					</td>
				</tr>
				<tr>
					<th scope="row"><?php echo esc_html__( 'Scanned items', 'summitcite' ); ?></th>
					<td><?php echo esc_html( number_format_i18n( $summary['scanned_count'] ) ); ?></td>
				</tr>
				<?php foreach ( $summary['breakdown'] as $type => $count ) : ?>
					<tr>
						<th scope="row"><?php echo esc_html( self::type_label( $type ) ); ?></th>
						<td><?php echo esc_html( number_format_i18n( $count ) ); ?></td>
					</tr>
				<?php endforeach; ?>
			</tbody>
		</table>
		<?php
	}

	/**
	 * Renders the "Scan All Published Content" control and its progress area.
	 *
	 * The progress element and its live region are present in markup whether
	 * or not a scan is running; the script toggles their state rather than
	 * inserting them, so a screen reader announces progress through the same
	 * element for the whole run.
	 *
	 * @since 1.5.0
	 *
	 * @param array<int, string> $types Currently configured and allowed post types.
	 * @return void
	 */
	private function render_scan_all( array $types ) {
		$snapshot = $this->store->eligible_snapshot( $types );
		$total    = null === $snapshot ? 0 : count( $snapshot );

		?>
		<h2><?php echo esc_html__( 'Scan', 'summitcite' ); ?></h2>
		<p>
			<button type="button" id="aive-density-scan-all" class="button button-primary" <?php disabled( 0 === $total ); ?>>
				<?php echo esc_html__( 'Scan All Published Content', 'summitcite' ); ?>
			</button>
		</p>
		<p>
			<progress id="aive-density-progress" max="<?php echo esc_attr( (string) max( 1, $total ) ); ?>" value="0" style="display:none;width:100%;max-width:30em;"></progress>
		</p>
		<p id="aive-density-status" role="status" aria-live="polite"></p>
		<?php
		if ( 0 === $total ) {
			printf(
				'<p class="description">%s</p>',
				esc_html__( 'There is no eligible published content to scan yet.', 'summitcite' )
			);
		}
	}

	/**
	 * Renders the type filter and the worst-first results table.
	 *
	 * @since 1.5.0
	 *
	 * @param array<int, string> $types Currently configured and allowed post types.
	 * @return void
	 */
	private function render_table( array $types ) {
		$filter = $this->requested_type_filter( $types );
		$paged  = $this->requested_page();
		$offset = ( $paged - 1 ) * self::PER_PAGE;

		$page = $this->store->listing( $types, $filter, self::PER_PAGE, $offset );

		?>
		<h2><?php echo esc_html__( 'Content', 'summitcite' ); ?></h2>
		<?php $this->render_filter_form( $types, $filter ); ?>
		<?php

		if ( null === $page ) {
			printf(
				'<p role="status" class="notice notice-error inline">%s</p>',
				esc_html__( 'The list could not be loaded.', 'summitcite' )
			);

			return;
		}

		if ( 0 === $page['total'] ) {
			printf(
				'<p>%s</p>',
				esc_html__( 'No eligible published content matches this filter yet.', 'summitcite' )
			);

			return;
		}

		?>
		<table class="widefat striped">
			<caption class="screen-reader-text"><?php echo esc_html__( 'Answer density by content item, worst score first', 'summitcite' ); ?></caption>
			<thead>
				<tr>
					<th scope="col"><?php echo esc_html__( 'Title', 'summitcite' ); ?></th>
					<th scope="col"><?php echo esc_html__( 'Type', 'summitcite' ); ?></th>
					<th scope="col"><?php echo esc_html__( 'Score', 'summitcite' ); ?></th>
					<th scope="col"><?php echo esc_html__( 'Questions', 'summitcite' ); ?></th>
					<th scope="col"><?php echo esc_html__( 'Direct / Buried / Unanswered', 'summitcite' ); ?></th>
					<th scope="col"><?php echo esc_html__( 'Score breakdown', 'summitcite' ); ?></th>
					<th scope="col"><?php echo esc_html__( 'Last scanned', 'summitcite' ); ?></th>
					<th scope="col"><?php echo esc_html__( 'Action', 'summitcite' ); ?></th>
				</tr>
			</thead>
			<tbody id="aive-density-rows">
				<?php foreach ( $page['rows'] as $row ) : ?>
					<?php $this->render_row( $row ); ?>
				<?php endforeach; ?>
			</tbody>
		</table>
		<?php

		$this->render_pagination( $page['total'], $paged, $filter );
	}

	/**
	 * Renders one table row.
	 *
	 * @since 1.5.0
	 *
	 * @param array<string, mixed> $row Row from AnswerDensityStore::listing().
	 * @return void
	 */
	private function render_row( array $row ) {
		$edit_link = get_edit_post_link( $row['post_id'], 'raw' );
		$title     = get_the_title( $row['post_id'] );
		$title     = '' === $title ? __( '(no title)', 'summitcite' ) : $title;

		?>
		<tr data-post-id="<?php echo esc_attr( (string) $row['post_id'] ); ?>">
			<td>
				<?php if ( null !== $edit_link ) : ?>
					<a href="<?php echo esc_url( $edit_link ); ?>"><?php echo esc_html( $title ); ?></a>
				<?php else : ?>
					<?php echo esc_html( $title ); ?>
				<?php endif; ?>
			</td>
			<td><?php echo esc_html( self::type_label( $row['post_type'] ) ); ?></td>
			<td class="aive-density-score"><?php echo esc_html( $this->score_cell( $row ) ); ?></td>
			<td class="aive-density-questions"><?php echo esc_html( null === $row['questions'] ? '—' : number_format_i18n( $row['questions'] ) ); ?></td>
			<td class="aive-density-breakdown"><?php echo esc_html( $this->breakdown_cell( $row ) ); ?></td>
			<td class="aive-density-score-breakdown"><?php echo esc_html( $this->score_breakdown_cell( $row ) ); ?></td>
			<td class="aive-density-scanned-at"><?php echo esc_html( $this->scanned_at_cell( $row ) ); ?></td>
			<td>
				<button type="button" class="button aive-density-scan-one" data-post-id="<?php echo esc_attr( (string) $row['post_id'] ); ?>">
					<?php echo esc_html__( 'Scan', 'summitcite' ); ?>
				</button>
			</td>
		</tr>
		<?php
	}

	/**
	 * Returns the text content of the score cell for one row.
	 *
	 * Never color alone: the state word is always present in the text itself.
	 *
	 * @since 1.5.0
	 *
	 * @param array<string, mixed> $row Row from AnswerDensityStore::listing().
	 * @return string Cell text.
	 */
	private function score_cell( array $row ) {
		if ( null === $row['state'] ) {
			return __( 'Not yet scanned', 'summitcite' );
		}

		if ( AnswerDensityParser::STATE_ERROR === $row['state'] ) {
			return __( 'Error — content too large to scan', 'summitcite' );
		}

		return sprintf(
			/* translators: %d: score out of 100. */
			__( '%d / 100', 'summitcite' ),
			(int) $row['score']
		);
	}

	/**
	 * Returns the text content of the direct/buried/unanswered cell.
	 *
	 * @since 1.5.0
	 *
	 * @param array<string, mixed> $row Row from AnswerDensityStore::listing().
	 * @return string Cell text.
	 */
	private function breakdown_cell( array $row ) {
		if ( null === $row['state'] || AnswerDensityParser::STATE_ERROR === $row['state'] ) {
			return '—';
		}

		return sprintf(
			'%1$d / %2$d / %3$d',
			(int) $row['direct'],
			(int) $row['buried'],
			(int) $row['unanswered']
		);
	}

	/**
	 * Returns the text content of the transparent score breakdown cell.
	 *
	 * Surfaces the exact values {@see \PressRoost\AIVE\AnswerDensity\AnswerDensityScorer::summarize()}
	 * already computes - the contract requires the UI itself to show the raw
	 * coverage ratio, each point contribution and the algorithm version, not
	 * only the final score.
	 *
	 * @since 1.7.1
	 *
	 * @param array<string, mixed> $row Row from AnswerDensityStore::listing().
	 * @return string Cell text.
	 */
	private function score_breakdown_cell( array $row ) {
		if ( null === $row['state'] || AnswerDensityParser::STATE_ERROR === $row['state'] ) {
			return '—';
		}

		$breakdown = $row['score_breakdown'];

		if ( ! isset( $breakdown['coverage_raw'], $breakdown['coverage_points'], $breakdown['quality_points'], $breakdown['structure_points'] )
			|| null === $row['algorithm_version']
		) {
			return '—';
		}

		return sprintf(
			/* translators: 1: coverage ratio, two decimal places. 2: coverage points, one decimal place. 3: quality points, one decimal place. 4: structure points, one decimal place. 5: algorithm version number. */
			__( 'Coverage %1$s (%2$s pts) · Quality %3$s pts · Structure %4$s pts · Algorithm v%5$d', 'summitcite' ),
			number_format_i18n( (float) $breakdown['coverage_raw'], 2 ),
			number_format_i18n( (float) $breakdown['coverage_points'], 1 ),
			number_format_i18n( (float) $breakdown['quality_points'], 1 ),
			number_format_i18n( (float) $breakdown['structure_points'], 1 ),
			(int) $row['algorithm_version']
		);
	}

	/**
	 * Returns the text content of the last-scanned cell, in the site timezone.
	 *
	 * @since 1.5.0
	 *
	 * @param array<string, mixed> $row Row from AnswerDensityStore::listing().
	 * @return string Cell text.
	 */
	private function scanned_at_cell( array $row ) {
		if ( null === $row['scanned_at'] ) {
			return __( 'Never', 'summitcite' );
		}

		$timestamp = strtotime( $row['scanned_at'] . ' UTC' );

		if ( false === $timestamp ) {
			return __( 'Unknown', 'summitcite' );
		}

		return wp_date( get_option( 'date_format' ) . ' ' . get_option( 'time_format' ), $timestamp );
	}

	/**
	 * Renders the type filter form.
	 *
	 * @since 1.5.0
	 *
	 * @param array<int, string> $types  Currently configured and allowed post types.
	 * @param string             $filter Requested type, or '' for every configured type.
	 * @return void
	 */
	private function render_filter_form( array $types, $filter ) {
		?>
		<form method="get" action="<?php echo esc_url( admin_url( 'admin.php' ) ); ?>" style="margin-bottom:1em;">
			<input type="hidden" name="page" value="<?php echo esc_attr( self::PAGE_SLUG ); ?>">
			<label for="aive-density-type-filter"><?php echo esc_html__( 'Filter by type', 'summitcite' ); ?></label>
			<select id="aive-density-type-filter" name="aive_density_type">
				<option value="" <?php selected( '', $filter ); ?>><?php echo esc_html__( 'All configured types', 'summitcite' ); ?></option>
				<?php foreach ( $types as $type ) : ?>
					<option value="<?php echo esc_attr( $type ); ?>" <?php selected( $type, $filter ); ?>><?php echo esc_html( self::type_label( $type ) ); ?></option>
				<?php endforeach; ?>
			</select>
			<?php submit_button( __( 'Filter', 'summitcite' ), 'secondary', '', false ); ?>
		</form>
		<?php
	}

	/**
	 * Renders simple previous/next pagination, preserving the type filter.
	 *
	 * @since 1.5.0
	 *
	 * @param int    $total  Total matching rows.
	 * @param int    $paged  Current page, 1-based.
	 * @param string $filter Requested type, or '' for every configured type.
	 * @return void
	 */
	private function render_pagination( $total, $paged, $filter ) {
		$pages = (int) ceil( $total / self::PER_PAGE );

		if ( $pages <= 1 ) {
			return;
		}

		$base_args = array( 'page' => self::PAGE_SLUG );

		if ( '' !== $filter ) {
			$base_args['aive_density_type'] = $filter;
		}

		?>
		<p class="tablenav-pages">
			<?php
			printf(
				/* translators: 1: current page, 2: total pages. */
				esc_html__( 'Page %1$d of %2$d', 'summitcite' ),
				(int) $paged,
				(int) $pages
			);
			?>
			<?php if ( $paged > 1 ) : ?>
				<a class="button" href="<?php echo esc_url( add_query_arg( array_merge( $base_args, array( 'paged' => $paged - 1 ) ), admin_url( 'admin.php' ) ) ); ?>"><?php echo esc_html__( 'Previous', 'summitcite' ); ?></a>
			<?php endif; ?>
			<?php if ( $paged < $pages ) : ?>
				<a class="button" href="<?php echo esc_url( add_query_arg( array_merge( $base_args, array( 'paged' => $paged + 1 ) ), admin_url( 'admin.php' ) ) ); ?>"><?php echo esc_html__( 'Next', 'summitcite' ); ?></a>
			<?php endif; ?>
		</p>
		<?php
	}

	/**
	 * Returns the requested page number, bounded to a positive integer.
	 *
	 * @since 1.5.0
	 *
	 * @return int Requested page, at least 1.
	 */
	private function requested_page() {
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- A read-only GET pager that changes no state; capability is checked in render().
		if ( ! isset( $_GET['paged'] ) || ! is_scalar( $_GET['paged'] ) ) {
			return 1;
		}

		return max( 1, absint( wp_unslash( $_GET['paged'] ) ) ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended -- See above.
	}

	/**
	 * Returns the requested type filter, or '' when it is absent or invalid.
	 *
	 * @since 1.5.0
	 *
	 * @param array<int, string> $types Currently configured and allowed post types.
	 * @return string Validated type, or ''.
	 */
	private function requested_type_filter( array $types ) {
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- A read-only GET filter that changes no state; capability is checked in render().
		if ( ! isset( $_GET['aive_density_type'] ) || ! is_scalar( $_GET['aive_density_type'] ) ) {
			return '';
		}

		$requested = sanitize_key( wp_unslash( $_GET['aive_density_type'] ) ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended -- See above.

		return in_array( $requested, $types, true ) ? $requested : '';
	}

	/**
	 * Returns the display label for a post type.
	 *
	 * @since 1.5.0
	 *
	 * @param string $type Post type name.
	 * @return string Label.
	 */
	private static function type_label( $type ) {
		$object = get_post_type_object( $type );

		return null === $object ? $type : (string) $object->labels->singular_name;
	}
}