<?php
/**
 * Builds the per-session summary from request records.
 *
 * @package Bloatwright
 */

namespace Bloatwright\Services;

use Bloatwright\Profiler\Owner;

/**
 * Aggregator.
 */
class Aggregator {

	/**
	 * Autoload analyzer.
	 *
	 * @var AutoloadAnalyzer
	 */
	private $autoload;

	/**
	 * Cron analyzer.
	 *
	 * @var CronAnalyzer
	 */
	private $cron;

	/**
	 * Constructor.
	 *
	 * @param AutoloadAnalyzer $autoload Autoload.
	 * @param CronAnalyzer     $cron Cron.
	 */
	public function __construct( AutoloadAnalyzer $autoload, CronAnalyzer $cron ) {
		$this->autoload = $autoload;
		$this->cron     = $cron;
	}

	/**
	 * Summarise.
	 *
	 * @param array $session Session row.
	 * @param array $requests Request rows (decoded).
	 */
	public function summarize( array $session, array $requests ): array {
		$owner_desc  = array();
		$by_url      = array(); // url => pass => record.
		$duplicates  = array();
		$queries_off = false;
		foreach ( $requests as $r ) {
			$by_url[ $r['url'] ][ $r['pass'] ] = $r;
			if ( isset( $r['data']['meta']['savequeries'] ) && ! $r['data']['meta']['savequeries'] ) {
				$queries_off = true; // SAVEQUERIES defined as false in wp-config.php: the queries stay empty.
			}
			foreach ( (array) ( $r['data']['descriptors'] ?? array() ) as $k => $d ) {
				$owner_desc[ $k ] = Owner::label( (array) $d );
			}
			if ( ! empty( $r['data']['meta']['is_admin'] ) ) {
				continue; // Duplicate libraries are a front-end finding: what admin pages load is left out.
			}
			foreach ( (array) ( $r['data']['duplicates'] ?? array() ) as $d ) {
				$duplicates[ $d['library'] . '|' . implode( ',', $d['owners'] ) ] = $d;
			}
		}
		$urls   = array();
		$owners = array();
		foreach ( $by_url as $url => $passes ) {
			$n        = count( $passes );
			$totals   = array_map(
				static function ( $r ) {
					return (float) $r['total_ms'];
				},
				$passes
			);
			$queries  = array_map(
				static function ( $r ) {
					return (int) $r['query_count'];
				},
				$passes
			);
			$is_admin = false;
			$overhead = 0.0;
			$mem      = 0;
			foreach ( $passes as $r ) {
				$is_admin  = ! empty( $r['data']['meta']['is_admin'] );
				$overhead += (float) ( $r['data']['meta']['overhead_ms'] ?? 0 );
				$mem       = max( $mem, (int) $r['peak_mem_kb'] );
			}
			$urls[ $url ] = array(
				'url'         => $url,
				'label'       => UrlSet::describe( (string) $url )['label'],
				'is_admin'    => $is_admin,
				'passes'      => $n,
				'total_ms'    => round( array_sum( $totals ) / $n, 2 ),
				'min_ms'      => round( min( $totals ), 2 ),
				'max_ms'      => round( max( $totals ), 2 ),
				'queries'     => (int) round( array_sum( $queries ) / $n ),
				'overhead_ms' => round( $overhead / $n, 2 ),
				'peak_mem_kb' => $mem,
			);
			// Per owner per URL averages.
			$acc = array();
			foreach ( $passes as $r ) {
				foreach ( (array) ( $r['data']['owners'] ?? array() ) as $key => $o ) {
					if ( ! isset( $acc[ $key ] ) ) {
						$acc[ $key ] = array(
							'php'      => array(),
							'incl'     => array(),
							'queries'  => array(),
							'query_ms' => array(),
							'bytes'    => 0,
							'unknown'  => 0,
							'blocking' => 0,
							'blk_b'    => 0,
							'hooks'    => array(),
							'slowest'  => array(),
							'assets'   => array(),
						);
					}
					$acc[ $key ]['php'][]      = (float) ( $o['php_ms_self'] ?? 0 );
					$acc[ $key ]['incl'][]     = (float) ( $o['php_ms_incl'] ?? 0 );
					$acc[ $key ]['queries'][]  = (int) ( $o['queries']['count'] ?? 0 );
					$acc[ $key ]['query_ms'][] = (float) ( $o['queries']['ms'] ?? 0 );
					$acc[ $key ]['bytes']      = max( $acc[ $key ]['bytes'], (int) ( $o['asset_bytes'] ?? 0 ) );
					$acc[ $key ]['unknown']    = max( $acc[ $key ]['unknown'], (int) ( $o['assets_unknown'] ?? 0 ) );
					$acc[ $key ]['blocking']   = max( $acc[ $key ]['blocking'], (int) ( $o['blocking'] ?? 0 ) );
					$acc[ $key ]['blk_b']      = max( $acc[ $key ]['blk_b'], self::blocking_bytes( (array) $o ) );
					foreach ( (array) ( $o['hooks'] ?? array() ) as $h ) {
						$acc[ $key ]['hooks'][ $h['hook'] ] = ( $acc[ $key ]['hooks'][ $h['hook'] ] ?? 0 ) + (float) $h['ms'] / $n;
					}
					foreach ( (array) ( $o['queries']['slowest'] ?? array() ) as $q ) {
						$acc[ $key ]['slowest'][] = $q + array( 'url' => $url );
					}
					foreach ( (array) ( $o['assets'] ?? array() ) as $a ) {
						$acc[ $key ]['assets'][ $a['type'] . ':' . $a['handle'] ] = $a;
					}
				}
			}
			foreach ( $acc as $key => $a ) {
				if ( ! isset( $owners[ $key ] ) ) {
					$owners[ $key ] = array(
						'key'          => $key,
						'per_url'      => array(),
						'hooks'        => array(),
						'slowest'      => array(),
						'assets'       => array(),
						'php_samples'  => array(),
						'incl_samples' => array(),
					);
				}
				$owners[ $key ]['per_url'][ $url ] = array(
					'php_ms'         => round( array_sum( $a['php'] ) / $n, 2 ),
					'php_min'        => round( min( $a['php'] ), 2 ),
					'php_max'        => round( max( $a['php'] ), 2 ),
					'php_incl_ms'    => round( array_sum( $a['incl'] ) / $n, 2 ),
					'php_pct'        => $urls[ $url ]['total_ms'] > 0 ? round( ( array_sum( $a['php'] ) / $n ) / $urls[ $url ]['total_ms'] * 100, 1 ) : 0.0,
					'queries'        => (int) round( array_sum( $a['queries'] ) / $n ),
					'query_ms'       => round( array_sum( $a['query_ms'] ) / $n, 2 ),
					'assets_kb'      => round( $a['bytes'] / 1024, 1 ),
					'assets_unknown' => $a['unknown'],
					'blocking'       => $a['blocking'],
					'blocking_kb'    => round( $a['blk_b'] / 1024, 1 ),
				);
				$owners[ $key ]['php_samples']     = array_merge( $owners[ $key ]['php_samples'], $a['php'] );
				$owners[ $key ]['incl_samples']    = array_merge( $owners[ $key ]['incl_samples'], $a['incl'] );
				foreach ( $a['hooks'] as $hook => $ms ) {
					$owners[ $key ]['hooks'][ $hook ] = ( $owners[ $key ]['hooks'][ $hook ] ?? 0 ) + $ms;
				}
				$owners[ $key ]['slowest'] = array_merge( $owners[ $key ]['slowest'], $a['slowest'] );
				if ( ! $is_admin ) {
					$owners[ $key ]['assets'] = $owners[ $key ]['assets'] + $a['assets']; // Front-end assets only.
				}
			}
		}
		$autoload = $this->autoload->analyze();
		$cron     = $this->cron->analyze();
		foreach ( array_keys( $autoload['owners'] ) as $key ) {
			if ( ! isset( $owners[ $key ] ) && ( isset( $owner_desc[ $key ] ) || isset( $autoload['descriptors'][ $key ] ) ) ) {
				$owners[ $key ] = array(
					'key'          => $key,
					'per_url'      => array(),
					'hooks'        => array(),
					'slowest'      => array(),
					'assets'       => array(),
					'php_samples'  => array( 0.0 ),
					'incl_samples' => array( 0.0 ),
				);
			}
		}
		$n_urls   = max( 1, count( $urls ) );
		$excluded = self::excluded_key( (string) ( $session['exclude_slug'] ?? '' ) );
		foreach ( $owners as $key => $o ) {
			$desc    = $owner_desc[ $key ] ?? $autoload['descriptors'][ $key ] ?? array(
				'key'  => $key,
				'type' => 'unknown',
				'name' => $key,
			);
			$slug    = self::slug( $desc );
			$php     = $o['php_samples'];
			$sum_php = 0.0;
			$sum_q   = 0;
			$sum_qms = 0.0;
			$kb      = 0.0;
			$unknown = 0;
			$block   = 0;
			$blk_kb  = 0.0;
			$adm_kb  = 0.0;
			foreach ( $o['per_url'] as $url => $u ) {
				$sum_php += $u['php_ms'];
				$sum_q   += $u['queries'];
				$sum_qms += $u['query_ms'];
				if ( ! empty( $urls[ $url ]['is_admin'] ) ) {
					$adm_kb = max( $adm_kb, $u['assets_kb'] ); // Reported apart: admin pages are not front-end pages.
					continue;
				}
				$kb      = max( $kb, $u['assets_kb'] );
				$unknown = max( $unknown, $u['assets_unknown'] );
				$block   = max( $block, $u['blocking'] );
				$blk_kb  = max( $blk_kb, $u['blocking_kb'] );
			}
			arsort( $o['hooks'] );
			usort(
				$o['slowest'],
				static function ( $x, $y ) {
					return $y['ms'] <=> $x['ms'];
				}
			);
			$dups = array();
			foreach ( $duplicates as $d ) {
				if ( in_array( $key, (array) $d['owners'], true ) ) {
					$lib = (string) $d['library'];
					foreach ( (array) $d['owners'] as $ok ) {
						if ( $ok !== $key ) {
							$dups[ $lib ]['others'][ $ok ] = (string) ( $owner_desc[ $ok ]['name'] ?? $ok );
						}
					}
					$dups[ $lib ]['library'] = $lib; // One entry per library, others merged across URLs.
				}
			}
			$dups            = array_values(
				array_map(
					static function ( $d ) {
						return array(
							'library' => $d['library'],
							'others'  => array_values( $d['others'] ),
						);
					},
					$dups
				)
			);
			$row             = array(
				'key'               => $key,
				'name'              => (string) $desc['name'],
				'type'              => (string) $desc['type'],
				'slug'              => $slug,
				'file'              => (string) ( $desc['file'] ?? '' ),
				'installed'         => ! empty( $desc['installed'] ),
				'excluded'          => $key === $excluded,
				'php_ms'            => round( $sum_php / $n_urls, 2 ),
				'php_min'           => round( min( $php ), 2 ),
				'php_max'           => round( max( $php ), 2 ),
				'php_incl_ms'       => round( array_sum( $o['incl_samples'] ) / max( 1, count( $o['incl_samples'] ) ), 2 ),
				'queries'           => (int) round( $sum_q / $n_urls ),
				'query_ms'          => round( $sum_qms / $n_urls, 2 ),
				'assets_kb'         => $kb,
				'assets_unknown'    => $unknown,
				'admin_assets_kb'   => $adm_kb,
				'blocking'          => $block,
				'blocking_kb'       => $blk_kb,
				'autoload_kb'       => round( (float) ( $autoload['owners'][ $key ]['bytes'] ?? 0 ) / 1024, 1 ),
				'autoload_count'    => (int) ( $autoload['owners'][ $key ]['count'] ?? 0 ),
				'autoload_rows'     => (array) ( $autoload['owners'][ $key ]['rows'] ?? array() ),
				'cron_per_day'      => (float) ( $cron['owners'][ $key ]['per_day'] ?? 0 ),
				'cron_events'       => (array) ( $cron['owners'][ $key ]['events'] ?? array() ),
				'cron_interval_min' => (float) ( $cron['owners'][ $key ]['min_interval_min'] ?? 0 ),
				'per_url'           => $o['per_url'],
				'top_hooks'         => array_slice(
					array_map(
						static function ( $hook, $ms ) use ( $n_urls ) {
							return array(
								'hook' => $hook,
								'ms'   => round( $ms / $n_urls, 2 ),
							);
						},
						array_keys( $o['hooks'] ),
						$o['hooks']
					),
					0,
					15
				),
				'slowest_queries'   => array_slice( $o['slowest'], 0, 10 ),
				'assets'            => array_values( $o['assets'] ),
				'duplicates'        => $dups,
			);
			$row['verdicts'] = Verdicts::for_owner( $row, $urls, $slug );
			$owners[ $key ]  = $row;
		}
		$owners = Scoring::apply( $owners );
		$front  = array();
		$admin  = array();
		$q_all  = 0;
		foreach ( $urls as $u ) {
			if ( $u['is_admin'] ) {
				$admin[] = $u['total_ms'];
			} else {
				$front[] = $u['total_ms'];
			}
			$q_all += $u['queries'];
		}
		return array(
			'owners'       => $owners,
			'urls'         => $urls,
			'totals'       => array(
				'frontend_ms' => $front ? round( array_sum( $front ) / count( $front ), 2 ) : 0.0,
				'admin_ms'    => $admin ? round( array_sum( $admin ) / count( $admin ), 2 ) : 0.0,
				'queries'     => $q_all,
				'requests'    => count( $requests ),
			),
			'duplicates'   => array_values( $duplicates ),
			'autoload'     => array(
				'total_kb' => round( $autoload['total_bytes'] / 1024, 1 ),
				'unknown'  => $autoload['unknown'],
			),
			'cron'         => array(
				'total_per_day' => $cron['total_per_day'],
				'orphans'       => $cron['orphans'],
			),
			'exclude'      => (string) ( $session['exclude_slug'] ?? '' ),
			'object_cache' => (bool) wp_using_ext_object_cache(),
			'queries_off'  => $queries_off,
			'generated_at' => current_time( 'mysql', true ),
			'version'      => BLOATWRIGHT_VERSION,
		);
	}

	/**
	 * Size of an owner's render-blocking assets in one request record: the recorded total, or (for
	 * records written before it was stored) the sum over its blocking assets.
	 *
	 * @param array $o Owner entry of a request record.
	 */
	public static function blocking_bytes( array $o ): int {
		if ( isset( $o['blocking_bytes'] ) ) {
			return (int) $o['blocking_bytes'];
		}
		$bytes = 0;
		foreach ( (array) ( $o['assets'] ?? array() ) as $a ) {
			if ( ! empty( $a['blocking'] ) ) {
				$bytes += max( 0, (int) ( $a['bytes'] ?? 0 ) ) + (int) ( $a['inline'] ?? 0 );
			}
		}
		return $bytes;
	}

	/**
	 * Owner key of the plugin file a "try without" session filtered out ('' when none).
	 *
	 * @param string $file Plugin file, e.g. "example-slider/example-slider.php".
	 */
	public static function excluded_key( string $file ): string {
		if ( '' === $file ) {
			return '';
		}
		$parts = explode( '/', $file );
		return 'plugin:' . ( count( $parts ) > 1 ? $parts[0] : preg_replace( '/\.php$/', '', $parts[0] ) );
	}

	/**
	 * Flag the row of the plugin a "try without" session filtered out, for summaries stored before
	 * rows carried the flag. Rank and weight stay as stored; the screens hide them for this row.
	 *
	 * @param array  $owners Owner summaries (key => row).
	 * @param string $file Plugin file left out of the session ('' when none).
	 * @return array
	 */
	public static function mark_excluded( array $owners, string $file ): array {
		$key = self::excluded_key( $file );
		if ( '' !== $key && isset( $owners[ $key ] ) && ! isset( $owners[ $key ]['excluded'] ) ) {
			$owners[ $key ]['excluded'] = true;
			$owners[ $key ]['verdicts'] = array( Verdicts::excluded() );
		}
		return $owners;
	}

	/**
	 * Directory slug from a descriptor.
	 *
	 * @param array $desc Descriptor.
	 */
	public static function slug( array $desc ): string {
		$key = (string) ( $desc['key'] ?? '' );
		if ( 0 === strpos( $key, 'plugin:' ) ) {
			return substr( $key, 7 );
		}
		if ( 0 === strpos( $key, 'theme:' ) ) {
			return substr( $key, 6 );
		}
		return $key;
	}
}