<?php
/**
 * This period vs the one before: the rows and the overall change.
 *
 * @package TurtleReport
 */

namespace TurtleReport\Reports;

use TurtleReport\Policy\Format;
use TurtleReport\Profiles\Profile;

defined( 'ABSPATH' ) || exit;

/**
 * Builds the "September vs August" table for emails and PDFs from a report
 * summary (Summary::build()), and the overall change across it.
 *
 * Each row holds both values, the change and a score: the change in percent
 * where up is good (so a better average position or a lower bounce rate
 * scores positive). The overall change is the average score of the main
 * rows; sub-rows (lead types) are shown but not averaged, so nothing counts
 * twice, and each row counts at most ±100%, so one small number tripling
 * doesn't decide the overall picture. A row whose earlier value is zero has
 * no percentage and isn't averaged.
 */
final class Comparison {

	/**
	 * Rows, grouped by section, in reading order.
	 *
	 * @param array   $data Summary data.
	 * @param Profile $site Site.
	 * @return array[] Items with section, label, cur, prev, change {text,color}, score (float|null), sub (bool), value and before (floats).
	 */
	public static function rows( array $data, Profile $site ) {
		$rows = array();
		$add  = static function ( $section, $label, $cur, $prev, $cur_text, $prev_text, $kind, $lower = false, $sub = false ) use ( &$rows ) {
			$cur  = (float) $cur;
			$prev = (float) $prev;
			if ( 'pos' === $kind ) {
				$lower = true;
			}
			$score = null;
			if ( $prev > 0 ) {
				$score = ( $cur - $prev ) / $prev * 100;
				if ( $lower ) {
					$score = -$score;
				}
			}
			$rows[] = array(
				'section' => $section,
				'label'   => $label,
				'cur'     => $cur_text,
				'prev'    => $prev_text,
				'change'  => Format::delta( $cur, $prev, $kind, $lower ),
				'score'   => $score,
				'sub'     => $sub,
				'value'   => $cur, // Raw numbers, for the PDF's arrows and bars.
				'before'  => $prev,
			);
		};

		if ( isset( $data['search']['cur'], $data['search']['prev'] ) && ! isset( $data['search']['error'] ) ) {
			$c = $data['search']['cur'];
			$p = $data['search']['prev'];
			$s = __( 'Google search', 'turtlereport' );
			$add( $s, __( 'Google clicks', 'turtlereport' ), $c['clicks'], $p['clicks'], Format::number( $c['clicks'] ), Format::number( $p['clicks'] ), 'rel' );
			$add( $s, __( 'Times seen in Google', 'turtlereport' ), $c['impressions'], $p['impressions'], Format::number( $c['impressions'] ), Format::number( $p['impressions'] ), 'rel' );
			$add( $s, __( 'Click-through rate', 'turtlereport' ), $c['ctr'], $p['ctr'], Format::metric( 'pct', $c['ctr'] ), Format::metric( 'pct', $p['ctr'] ), 'pts' );
			if ( $c['position'] > 0 || $p['position'] > 0 ) {
				$add( $s, __( 'Average position', 'turtlereport' ), $c['position'], $p['position'], number_format_i18n( (float) $c['position'], 1 ), $p['position'] > 0 ? number_format_i18n( (float) $p['position'], 1 ) : '–', 'pos' );
			}
		}

		if ( isset( $data['conversions']['cur'] ) && ! isset( $data['conversions']['error'] ) ) {
			$cv = $data['conversions'];
			/* translators: %s: what the site calls its conversions, e.g. Leads. */
			$s = sprintf( __( '%s from organic search', 'turtlereport' ), $site->conversion_label() );
			$add( $s, $site->conversion_label(), $cv['cur'], $cv['prev'], Format::number( $cv['cur'] ), Format::number( $cv['prev'] ), 'rel' );
			$groups = isset( $cv['groups'] ) ? (array) $cv['groups'] : array();
			if ( count( $groups ) > 1 ) {
				foreach ( $groups as $g ) {
					$add( $s, $g['label'], $g['cur'], $g['prev'], Format::number( $g['cur'] ), Format::number( $g['prev'] ), 'abs', false, true );
				}
			}
		}

		if ( isset( $data['traffic']['metrics'] ) && ! isset( $data['traffic']['error'] ) ) {
			$s = __( 'Website traffic', 'turtlereport' );
			foreach ( (array) $data['traffic']['metrics'] as $m ) {
				$pct = 'pct' === $m['format'];
				$add( $s, $m['label'], $m['cur'], $m['prev'], Format::metric( $m['format'], $m['cur'] ), Format::metric( $m['format'], $m['prev'] ), $pct ? 'pts' : 'rel', ! empty( $m['lower'] ) );
			}
		}

		if ( isset( $data['ai']['cur'] ) && ! isset( $data['ai']['error'] ) ) {
			$s = __( 'AI assistants', 'turtlereport' );
			$add( $s, __( 'Visits from AI assistants', 'turtlereport' ), $data['ai']['cur'], $data['ai']['prev'], Format::number( $data['ai']['cur'] ), Format::number( $data['ai']['prev'] ), 'rel' );
			if ( isset( $data['ai']['conv'] ) && ( $data['ai']['conv'] > 0 || $data['ai']['conv_prev'] > 0 ) ) {
				/* translators: %s: what the site calls its conversions. */
				$add( $s, sprintf( __( '%s from AI', 'turtlereport' ), $site->conversion_label() ), $data['ai']['conv'], $data['ai']['conv_prev'], Format::number( $data['ai']['conv'] ), Format::number( $data['ai']['conv_prev'] ), 'abs', false, true );
			}
		}

		if ( isset( $data['business']['cur'] ) && ! isset( $data['business']['error'] ) ) {
			$c = $data['business']['cur'];
			$p = $data['business']['prev'];
			$s = __( 'Google Business Profile', 'turtlereport' );
			foreach ( array(
				'calls' => __( 'Calls', 'turtlereport' ),
				'web'   => __( 'Website clicks', 'turtlereport' ),
				'dirs'  => __( 'Direction requests', 'turtlereport' ),
				'views' => __( 'Profile views', 'turtlereport' ),
			) as $k => $label ) {
				$add( $s, $label, $c[ $k ], $p[ $k ], Format::number( $c[ $k ] ), Format::number( $p[ $k ] ), 'rel' );
			}
		}
		return $rows;
	}

	/**
	 * The overall change: the average score of the main rows.
	 *
	 * @param array[] $rows From rows().
	 * @return array{average:float|null,text:string,color:string,better:int,worse:int,same:int,count:int}
	 */
	public static function overall( array $rows ) {
		$scores = array();
		$better = 0;
		$worse  = 0;
		$same   = 0;
		foreach ( $rows as $row ) {
			if ( $row['sub'] ) {
				continue;
			}
			if ( Format::GOOD === $row['change']['color'] ) {
				++$better;
			} elseif ( Format::BAD === $row['change']['color'] ) {
				++$worse;
			} else {
				++$same;
			}
			if ( null !== $row['score'] ) {
				// One small number tripling (15 → 45 calls) shouldn't swing the whole picture.
				$scores[] = max( -100.0, min( 100.0, (float) $row['score'] ) );
			}
		}
		$avg = $scores ? array_sum( $scores ) / count( $scores ) : null;
		if ( null === $avg ) {
			$text  = '–';
			$color = Format::FLAT;
		} elseif ( abs( $avg ) < 0.5 ) {
			$text  = __( 'No change', 'turtlereport' );
			$color = Format::FLAT;
		} else {
			$text  = ( $avg > 0 ? '+' : '−' ) . number_format_i18n( abs( $avg ), abs( $avg ) < 10 ? 1 : 0 ) . '%';
			$color = $avg > 0 ? Format::GOOD : Format::BAD;
		}
		return array(
			'average' => $avg,
			'text'    => $text,
			'color'   => $color,
			'better'  => $better,
			'worse'   => $worse,
			'same'    => $same,
			'count'   => count( $scores ),
		);
	}

	/**
	 * Column names: "September 2026" and "August 2026" for whole months,
	 * otherwise "This period" and the comparison period in words, e.g.
	 * "the previous 7 days" (Insights::versus()), so "Change vs …" reads.
	 *
	 * @param array $period Period with s, e, ps and pe.
	 * @return array{0:string,1:string}
	 */
	public static function columns( array $period ) {
		$month = static function ( $s, $e ) {
			$first = substr( $s, 8, 2 ) === '01';
			$last  = gmdate( 'Y-m-t', strtotime( $s . ' 12:00:00 UTC' ) ) === $e;
			return $first && $last ? wp_date( 'F Y', strtotime( $s . ' 12:00:00 UTC' ), new \DateTimeZone( 'UTC' ) ) : '';
		};
		$a     = $month( $period['s'], $period['e'] );
		$b     = $month( $period['ps'], $period['pe'] );
		if ( '' !== $a && '' !== $b ) {
			return array( $a, $b );
		}
		return array( __( 'This period', 'turtlereport' ), Insights::versus( $period ) );
	}
}