<?php
declare(strict_types=1);

namespace Unsupervised\Schedular\Booking;

class BookingRepository {

	private string $table;

	public function __construct( private \wpdb $db ) {
		$this->table = $db->prefix . 'us_lessons';
	}

	public function insert( Lesson $lesson ): int {
		$this->db->insert(
			$this->table,
			[
				'slot_id'       => $lesson->slotId,
				'offering_id'   => $lesson->offeringId,
				'student_id'    => $lesson->studentId,
				'instructor_id' => $lesson->instructorId,
				'recurrence'    => $lesson->recurrence,
				'series_id'     => $lesson->seriesId,
				'status'        => $lesson->status,
				'payment_id'    => $lesson->paymentId,
				'notes'         => $lesson->notes,
				'created_at'    => current_time( 'mysql' ),
			],
			[ '%d', '%d', '%d', '%d', '%s', '%d', '%s', '%d', '%s', '%s' ]
		);

		return $this->db->insert_id;
	}

	/**
	 * Create a weekly lesson series — one lesson per slot, all sharing a
	 * `series_id` (the id of the first lesson row).
	 *
	 * @param list<int> $slotIds Availability slot IDs to reserve, in order.
	 * @return list<int> Inserted lesson IDs.
	 */
	public function insertSeries( Lesson $template, array $slotIds ): array {
		$ids      = [];
		$seriesId = 0;

		foreach ( $slotIds as $slotId ) {
			$id = $this->insert(
				new Lesson(
					slotId:       $slotId,
					studentId:    $template->studentId,
					instructorId: $template->instructorId,
					offeringId:   $template->offeringId,
					recurrence:   Lesson::RECURRENCE_WEEKLY,
					seriesId:     $seriesId > 0 ? $seriesId : null,
					status:       $template->status,
					notes:        $template->notes,
				)
			);

			if ( 0 === $seriesId ) {
				$seriesId = $id;
				$this->setSeriesId( $id, $seriesId );
			}

			$ids[] = $id;
		}

		return $ids;
	}

	private function setSeriesId( int $id, int $seriesId ): void {
		$this->db->update(
			$this->table,
			[ 'series_id' => $seriesId ],
			[ 'id' => $id ],
			[ '%d' ],
			[ '%d' ]
		);
	}

	public function findById( int $id ): ?Lesson {
		$row = $this->db->get_row(
			$this->db->prepare( 'SELECT * FROM %i WHERE id = %d', $this->table, $id )
		);

		return $row ? Lesson::fromRow( $row ) : null;
	}

	/**
	 * Upcoming lessons for an instructor (status != cancelled, slot in the future).
	 *
	 * @return list<Lesson>
	 */
	public function findUpcomingForInstructor( int $instructorId ): array {
		$avTable = str_replace( 'us_lessons', 'us_availability', $this->table );

		$rows = $this->db->get_results(
			$this->db->prepare(
				'SELECT l.* FROM %i l
                 JOIN %i a ON a.id = l.slot_id
                 WHERE l.instructor_id = %d
                   AND l.status != %s
                   AND a.start_dt >= %s
                 ORDER BY a.start_dt ASC',
				$this->table,
				$avTable,
				$instructorId,
				Lesson::STATUS_CANCELLED,
				current_time( 'mysql' )
			)
		);

		return array_map( Lesson::fromRow( ... ), $rows ?? [] );
	}

	/**
	 * Upcoming lessons for a student (status != cancelled, slot in the future).
	 *
	 * @return list<Lesson>
	 */
	public function findUpcomingForStudent( int $studentId ): array {
		$avTable = str_replace( 'us_lessons', 'us_availability', $this->table );

		$rows = $this->db->get_results(
			$this->db->prepare(
				'SELECT l.* FROM %i l
                 JOIN %i a ON a.id = l.slot_id
                 WHERE l.student_id = %d
                   AND l.status != %s
                   AND a.start_dt >= %s
                 ORDER BY a.start_dt ASC',
				$this->table,
				$avTable,
				$studentId,
				Lesson::STATUS_CANCELLED,
				current_time( 'mysql' )
			)
		);

		return array_map( Lesson::fromRow( ... ), $rows ?? [] );
	}

	/**
	 * Count a student's upcoming, non-cancelled lessons (slot in the future).
	 */
	public function countUpcomingForStudent( int $studentId ): int {
		$avTable = str_replace( 'us_lessons', 'us_availability', $this->table );

		return (int) $this->db->get_var(
			$this->db->prepare(
				'SELECT COUNT(*) FROM %i l
                 JOIN %i a ON a.id = l.slot_id
                 WHERE l.student_id = %d
                   AND l.status != %s
                   AND a.start_dt >= %s',
				$this->table,
				$avTable,
				$studentId,
				Lesson::STATUS_CANCELLED,
				current_time( 'mysql' )
			)
		);
	}

	/**
	 * All lessons for a student.
	 *
	 * @return list<Lesson>
	 */
	public function findByStudent( int $studentId ): array {
		$rows = $this->db->get_results(
			$this->db->prepare(
				'SELECT * FROM %i WHERE student_id = %d ORDER BY created_at DESC',
				$this->table,
				$studentId
			)
		);

		return array_map( Lesson::fromRow( ... ), $rows ?? [] );
	}

	/**
	 * All upcoming lessons across all instructors (admin view).
	 *
	 * @return list<Lesson>
	 */
	public function findAllUpcoming(): array {
		$avTable = str_replace( 'us_lessons', 'us_availability', $this->table );

		$rows = $this->db->get_results(
			$this->db->prepare(
				'SELECT l.* FROM %i l
                 JOIN %i a ON a.id = l.slot_id
                 WHERE l.status != %s
                   AND a.start_dt >= %s
                 ORDER BY a.start_dt ASC',
				$this->table,
				$avTable,
				Lesson::STATUS_CANCELLED,
				current_time( 'mysql' )
			)
		);

		return array_map( Lesson::fromRow( ... ), $rows ?? [] );
	}

	/**
	 * Not-yet-billed lessons on a scheduled-billing (weekly / monthly) offering:
	 * status not cancelled and no payment attached yet. Each row carries the slot
	 * start time and the offering's billing fields so the daily billing scan can
	 * decide what is due without a second query per lesson. Ordered by student,
	 * offering and time so the scan can group a student's monthly lessons cheaply.
	 *
	 * @return list<\stdClass> Rows: id, student_id, instructor_id, offering_id,
	 *                         start_dt, billing_mode, title, price, currency,
	 *                         etransfer_email.
	 */
	public function findUnbilledScheduledLessons(): array {
		$avTable  = str_replace( 'us_lessons', 'us_availability', $this->table );
		$offTable = str_replace( 'us_lessons', 'us_offerings', $this->table );

		$rows = $this->db->get_results(
			$this->db->prepare(
				'SELECT l.id, l.student_id, l.instructor_id, l.offering_id,
				        a.start_dt,
				        o.billing_mode, o.title, o.price, o.currency, o.etransfer_email
				 FROM %i l
				 JOIN %i a ON a.id = l.slot_id
				 JOIN %i o ON o.id = l.offering_id
				 WHERE l.status != %s
				   AND l.payment_id IS NULL
				   AND o.billing_mode IN ( %s, %s )
				 ORDER BY l.student_id ASC, l.offering_id ASC, a.start_dt ASC',
				$this->table,
				$avTable,
				$offTable,
				Lesson::STATUS_CANCELLED,
				\Unsupervised\Schedular\Offering\Offering::BILLING_WEEKLY,
				\Unsupervised\Schedular\Offering\Offering::BILLING_MONTHLY
			)
		);

		return $rows ?? [];
	}

	/**
	 * How many lessons a payment covers — every lesson pointed at it, cancelled or
	 * not, since the payment was billed for all of them. Used to split a paid
	 * payment's total into a per-lesson share when one covered lesson is cancelled
	 * and credited. Never below zero.
	 */
	public function countByPaymentId( int $paymentId ): int {
		return (int) $this->db->get_var(
			$this->db->prepare(
				'SELECT COUNT(*) FROM %i WHERE payment_id = %d',
				$this->table,
				$paymentId
			)
		);
	}

	/**
	 * How many lessons belong to a weekly series — the whole reservation an upfront
	 * (full-term) payment covers, so cancelling one lesson credits its per-lesson
	 * share. Counts every lesson in the series, cancelled or not.
	 */
	public function countBySeries( int $seriesId ): int {
		return (int) $this->db->get_var(
			$this->db->prepare(
				'SELECT COUNT(*) FROM %i WHERE series_id = %d',
				$this->table,
				$seriesId
			)
		);
	}

	public function setPaymentId( int $id, int $paymentId ): bool {
		return false !== $this->db->update(
			$this->table,
			[ 'payment_id' => $paymentId ],
			[ 'id' => $id ],
			[ '%d' ],
			[ '%d' ]
		);
	}

	/**
	 * Update every non-cancelled lesson in a weekly series at once — e.g.
	 * confirming the whole reservation when its single upfront payment settles.
	 */
	public function updateStatusForSeries( int $seriesId, string $status ): bool {
		if ( ! in_array( $status, Lesson::VALID_STATUSES, true ) ) {
			return false;
		}

		$sql = $this->db->prepare(
			'UPDATE %i SET status = %s WHERE series_id = %d AND status != %s',
			$this->table,
			$status,
			$seriesId,
			Lesson::STATUS_CANCELLED
		);

		return null !== $sql && false !== $this->db->query( $sql );
	}

	public function updateStatus( int $id, string $status ): bool {
		if ( ! in_array( $status, Lesson::VALID_STATUSES, true ) ) {
			return false;
		}

		return (bool) $this->db->update(
			$this->table,
			[ 'status' => $status ],
			[ 'id' => $id ],
			[ '%s' ],
			[ '%d' ]
		);
	}
}