<?php
/**
 * The read path's front door. One job per file since Phase 17b: the dimension
 * table lives in Saddle_Analytics_Report_Table, the KPI cards in Saddle_Analytics_Summary, and this
 * class keeps the chart (timeseries) plus one-line delegators so
 * REST, CLI and Abilities callers never changed.
 *
 * Windows come from Saddle_Analytics_Window (all the date math, WP-free and unit-tested).
 * A window's upper bound is applied ONLY when it has one: with a plain range
 * enum `end` is null, the SQL is byte-identical to pre-Phase-13, and so are the
 * numbers. Explicit from/to and every compare query are what need the bound.
 */

defined( 'ABSPATH' ) || exit;

final class Saddle_Analytics_Report {

	const RANGES = array( 'today', '7d', '30d', '90d', 'all' );

	private Saddle_Analytics_Report_Table $tables;
	private Saddle_Analytics_Summary $cards;

	public function __construct( private wpdb $db ) {
		$this->tables = new Saddle_Analytics_Report_Table( $db );
		$this->cards  = new Saddle_Analytics_Summary( $db );
	}

	/** @return array[] Rows: value + every metric, sorted by $metric. */
	public function table( Saddle_Analytics_Dimension $d, string $metric, string $range, array $filters = array(), int $limit = 100, ?string $from = null, ?string $to = null ): array {
		return $this->tables->table( $d, $metric, $range, $filters, $limit, $from, $to );
	}

	/** The KPI cards; with $compare, 'previous' and 'delta' are added. */
	public function summary( string $range, ?string $from = null, ?string $to = null, bool $compare = false, array $filters = array() ): array {
		return $this->cards->summary( $range, $from, $to, $compare, $filters );
	}

	/**
	 * Visitors per bucket for the chart: hourly for a single day, daily
	 * otherwise. Every bucket in the window is present (zero-filled), so the
	 * chart always draws exactly as many points as the range has periods.
	 *
	 * With $compare, a 'previous' points array is added, bucketed over the
	 * preceding window at the same interval and the same count so the chart can
	 * align it index-to-index against the current series.
	 *
	 * @return array{interval:string, points:array<int,array{ts:int,visitors:int,pageviews:int}>, previous?:array}
	 */
	public function timeseries( string $range, ?string $from = null, ?string $to = null, bool $compare = false, array $filters = array() ): array {
		$now      = time();
		$window   = Saddle_Analytics_Window::resolve( $range, $from, $to, $now );
		$interval = Saddle_Analytics_Window::interval( $window );
		$count    = Saddle_Analytics_Window::buckets( $window, $interval, $now );

		// 'all' has no start; the chart still caps at 90 days (its KPIs stay lifetime).
		if ( null === $window['start'] ) {
			$window['start'] = gmdate( 'Y-m-d 00:00:00', $now - 89 * DAY_IN_SECONDS );
		}

		$series = array(
			'interval' => $interval,
			'points'   => $this->buckets( $window, $interval, $count, $filters ),
		);

		if ( $compare ) {
			// Same bucket count as the current series, deliberately: comparing
			// today's first 17 hours against yesterday's first 17 is like-for-like,
			// and the chart can align the two arrays index-to-index.
			$previous           = Saddle_Analytics_Window::previous( $window );
			$series['previous'] = null === $previous ? null : $this->buckets( $previous, $interval, $count, $filters );
		}

		return $series;
	}

	/** One window's zero-filled chart buckets, narrowed by the visitor filters. */
	private function buckets( array $window, string $interval, int $count, array $filters = array() ): array {
		$t      = Saddle_Analytics_Install::tables();
		$step   = 'hour' === $interval ? HOUR_IN_SECONDS : DAY_IN_SECONDS;
		$anchor = (string) $window['start'];

		list( $bounds, $bound_params ) = Saddle_Analytics_Window::bounds( $window, 'ts' );
		list( $scope, $scope_params )  = Saddle_Analytics_Dimensions::visitor_scope( $filters );

		// Integer buckets as an offset from a prepared UTC anchor — same reason
		// as Saddle_Analytics_Realtime: DATE_FORMAT/HOUR() are not portable to the SQLite
		// driver, and both UNIX_TIMESTAMP terms cancel MySQL's session zone.
		$hits = (array) $this->db->get_results(
			$this->db->prepare(
				"SELECT FLOOR((UNIX_TIMESTAMP(ts) - UNIX_TIMESTAMP(%s)) / %d) AS bucket,
				COUNT(DISTINCT visitor_id) AS visitors, COUNT(*) AS pageviews
				FROM {$t['hits']} WHERE event_type = 1{$bounds}{$scope} GROUP BY bucket", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				$anchor,
				$step,
				...array_merge( $bound_params, $scope_params )
			),
			ARRAY_A
		);

		// Cast the bucket key: drivers may hand FLOOR() back as "3" or "3.0".
		$by_bucket = array();
		foreach ( $hits as $row ) {
			$by_bucket[ (int) $row['bucket'] ] = $row;
		}

		$origin = (int) strtotime( $anchor . ' UTC' );
		$points = array();
		for ( $i = 0; $i < $count; $i++ ) {
			$points[] = array(
				'ts'        => $origin + $i * $step,
				'visitors'  => (int) ( $by_bucket[ $i ]['visitors'] ?? 0 ),
				'pageviews' => (int) ( $by_bucket[ $i ]['pageviews'] ?? 0 ),
			);
		}

		return $points;
	}

	/** Whole days a range spans; null = lifetime. */
	public function range_days( string $range ): ?int {
		return Saddle_Analytics_Window::days( $range );
	}

	/** Midnight of today−(N−1); null = lifetime. */
	public function range_start( string $range ): ?string {
		return Saddle_Analytics_Window::range_start( $range, time() );
	}
}