<?php

namespace RoosterLMS\Commerce;

use RoosterLMS\Content\CourseRepository;
use RoosterLMS\Data\Db;
use RoosterLMS\Data\SqlPart;
use RoosterLMS\Data\Transaction;
use RoosterLMS\Domain\Actor;
use RoosterLMS\Domain\DomainError;
use RoosterLMS\Domain\ErrorCode;
use RoosterLMS\Live\PhaseService;

defined( 'ABSPATH' ) || exit;

final class OfferService {

	private ?array $handlers = null;

	public function handlers(): array {
		if ( null === $this->handlers ) {
			$course = new CourseOfferHandler();
			$filtered = apply_filters( 'rooster_lms_offer_handlers', array( OfferTarget::COURSE->value => $course ) );
			$out      = array();
			foreach ( is_array( $filtered ) ? $filtered : array() as $key => $handler ) {
				if ( $handler instanceof OfferHandler && $handler->target()->value === (int) $key ) {
					$out[ (int) $key ] = $handler;
				}
			}
			$this->handlers = $out;
		}
		return $this->handlers;
	}

	public function handler( OfferTarget $target, bool $required = true ): ?OfferHandler {
		$handler = $this->handlers()[ $target->value ] ?? null;
		if ( null === $handler && $required ) {
			DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'target' ) );
		}
		return $handler;
	}

	public function save( int $product_id, int $variation_id, OfferTarget $target, int $target_id, array $options, Actor $actor ): Offer {
		if ( $product_id <= 0 || $variation_id < 0 ) {
			DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'product' ) );
		}
		$handler = $this->handler( $target );
		$handler->authorize( $target_id, $actor );
		$v = self::clean( $options );
		$handler->validate( $target_id, $v['scope_ids'] );
		$id = (int) Transaction::run(
			static function () use ( $product_id, $variation_id, $target, $target_id, $v ): int {
				global $wpdb;
				$now   = Transaction::now();
				$scope = array() === $v['scope_ids'] ? null : (string) wp_json_encode( $v['scope_ids'] );
				$id    = Db::value( 'SELECT id FROM %i WHERE product_id = %d AND variation_id = %d AND target_type = %d AND target_id = %d FOR UPDATE', Db::table( 'offers' ), $product_id, $variation_id, $target->value, $target_id );
				if ( null === $id ) {
					Db::query( 'INSERT INTO %i (product_id, variation_id, target_type, target_id, sale_window, grace_min, seats_per_qty, state, created_at, updated_at) VALUES (%d, %d, %d, %d, %d, %d, %d, %d, %s, %s)', Db::table( 'offers' ), $product_id, $variation_id, $target->value, $target_id, $v['window'], $v['grace_min'], $v['seats_per_qty'], $v['state'], $now, $now );
					$id = Db::insert_id();
				} else {
					$id = (int) $id;
					Db::query( 'UPDATE %i SET sale_window = %d, grace_min = %d, seats_per_qty = %d, state = %d, updated_at = %s WHERE id = %d', Db::table( 'offers' ), $v['window'], $v['grace_min'], $v['seats_per_qty'], $v['state'], $now, $id );
				}
				Db::query( null === $scope ? SqlPart::of( 'UPDATE %i SET scope_ids = NULL WHERE id = %d', Db::table( 'offers' ), $id ) : SqlPart::of( 'UPDATE %i SET scope_ids = %s WHERE id = %d', Db::table( 'offers' ), $scope, $id ) );
				Db::query( null === $v['access_days'] ? SqlPart::of( 'UPDATE %i SET access_days = NULL WHERE id = %d', Db::table( 'offers' ), $id ) : SqlPart::of( 'UPDATE %i SET access_days = %d WHERE id = %d', Db::table( 'offers' ), $v['access_days'], $id ) );
				return $id;
			}
		);
		return $this->get( $id );
	}

	public function set_state( int $id, OfferState $state, Actor $actor ): Offer {
		$offer = $this->get( $id );
		if ( null === $offer ) {
			DomainError::raise( ErrorCode::NOT_FOUND );
		}
		$this->handler( $offer->target_type )->authorize( $offer->target_id, $actor );
		Transaction::run(
			static function () use ( $id, $state ): void {
			Db::row( 'SELECT id FROM %i WHERE id = %d FOR UPDATE', Db::table( 'offers' ), $id );
				Db::query( 'UPDATE %i SET state = %d, updated_at = %s WHERE id = %d', Db::table( 'offers' ), $state->value, Transaction::now(), $id );
			}
		);
		return $this->get( $id );
	}

	public function delete( int $id, Actor $actor ): bool {
		$offer = $this->get( $id );
		if ( null === $offer ) {
			return false;
		}
		$this->handler( $offer->target_type )->authorize( $offer->target_id, $actor );
		Transaction::run(
			static function () use ( $id ): void {
			if ( null !== Db::value( 'SELECT id FROM %i WHERE offer_id = %d LIMIT 1 LOCK IN SHARE MODE', Db::table( 'sales' ), $id ) ) {
					DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'sold' ) );
				}
				Db::query( 'DELETE FROM %i WHERE id = %d', Db::table( 'offers' ), $id );
			}
		);
		return true;
	}

	public function get( int $id ): ?Offer {
		$row = Db::row( 'SELECT * FROM %i WHERE id = %d', Db::table( 'offers' ), $id );
		return null === $row ? null : Offer::from_row( $row );
	}

	public function for_product( int $product_id, int $variation_id = 0, bool $all = false ): array {
		global $wpdb;
		$sql = SqlPart::of( 'SELECT * FROM %i WHERE product_id = %d AND variation_id IN (0, %d)', Db::table( 'offers' ), $product_id, $variation_id );
		if ( ! $all ) {
			$sql = $sql->add( SqlPart::of( ' AND state = %d', OfferState::ACTIVE->value ) );
		}
		return array_map( array( Offer::class, 'from_row' ), Db::rows( $sql->add( ' ORDER BY variation_id DESC, id' ) ) );
	}

	public function for_products( array $product_ids, bool $all = false ): array {
		$product_ids = CourseRepository::ids( $product_ids );
		$out         = array_fill_keys( $product_ids, array() );
		if ( array() === $product_ids ) {
			return $out;
		}
		global $wpdb;
		$sql = SqlPart::of( 'SELECT * FROM %i WHERE product_id IN (' . implode( ',', array_fill( 0, count( $product_ids ), '%d' ) ) . ')', array_merge( array( Db::table( 'offers' ) ), $product_ids ) );
		if ( ! $all ) {
			$sql = $sql->add( SqlPart::of( ' AND state = %d', OfferState::ACTIVE->value ) );
		}
		foreach ( Db::rows( $sql->add( ' ORDER BY product_id, variation_id DESC, id' ) ) as $row ) {
			$offer                       = Offer::from_row( $row );
			$out[ $offer->product_id ][] = $offer;
		}
		return $out;
	}

	public function for_target( OfferTarget $target, int $target_id ): array {
		return array_map( array( Offer::class, 'from_row' ), Db::rows( 'SELECT * FROM %i WHERE target_type = %d AND target_id = %d ORDER BY state, product_id, variation_id', Db::table( 'offers' ), $target->value, $target_id ) );
	}

	public function on_sale( Offer $offer, ?\DateTimeImmutable $now = null ): bool {
		$handler = $this->handler( $offer->target_type, false );
		return OfferState::ACTIVE === $offer->state && null !== $handler && $handler->on_sale( $offer, $now ?? PhaseService::now() );
	}

	public function forget(): void {
		$this->handlers = null;
	}

	private static function clean( array $o ): array {
		$window = $o['window'] ?? OfferWindow::ALWAYS;
		$window = $window instanceof OfferWindow ? $window : OfferWindow::tryFrom( (int) $window );
		$state  = $o['state'] ?? OfferState::ACTIVE;
		$state  = $state instanceof OfferState ? $state : OfferState::tryFrom( (int) $state );
		if ( null === $window ) {
			DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'window' ) );
		}
		if ( null === $state ) {
			DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'state' ) );
		}
		$days = array_key_exists( 'access_days', $o ) && null !== $o['access_days'] && '' !== $o['access_days'] ? (int) $o['access_days'] : null;
		$v    = array(
			'scope_ids'     => CourseRepository::ids( (array) ( $o['scope_ids'] ?? array() ) ),
			'window'        => $window->value,
			'grace_min'     => (int) ( $o['grace_min'] ?? 0 ),
			'access_days'   => null === $days || 0 === $days ? null : $days,
			'seats_per_qty' => (int) ( $o['seats_per_qty'] ?? 1 ),
			'state'         => $state->value,
		);
		sort( $v['scope_ids'] );
		if ( $v['grace_min'] < 0 || $v['grace_min'] > 1440 ) {
			DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'grace_min' ) );
		}
		if ( null !== $v['access_days'] && ( $v['access_days'] < 1 || $v['access_days'] > 36500 ) ) {
			DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'access_days' ) );
		}
		if ( $v['seats_per_qty'] < 1 || $v['seats_per_qty'] > 100000 ) {
			DomainError::raise( ErrorCode::INVALID, array( 'reason' => 'seats_per_qty' ) );
		}
		return $v;
	}
}