<?php
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

final class EB4TEC_WooCommerce {

	public function __construct(
		private readonly EB4TEC_API_Client     $api,
		private readonly EB4TEC_Ticket_Manager $ticket_manager,
		private readonly EB4TEC_QR_Code        $qr,
	) {
		add_action( 'woocommerce_order_status_completed',  [ $this, 'on_order_completed' ] );
		add_action( 'woocommerce_order_status_refunded',   [ $this, 'on_order_refunded' ] );
		add_action( 'woocommerce_order_status_cancelled',  [ $this, 'on_order_refunded' ] );
		add_action( 'add_meta_boxes',                      [ $this, 'add_meta_boxes' ] );
		add_action( 'save_post',                           [ $this, 'save_product_meta_box' ] );
		add_action( 'woocommerce_thankyou',                [ $this, 'show_qr_on_thankyou' ] );
		add_action( 'woocommerce_email_order_details',     [ $this, 'inject_qr_into_email' ], 20, 4 );
	}

	// ---------------------------------------------------------------------------
	// WooCommerce product creation / update
	// ---------------------------------------------------------------------------

	public function sync_event_product( int $post_id ): int|WP_Error {
		$existing_product_id = (int) get_post_meta( $post_id, '_eb4tec_wp_product_id', true );

		if ( $existing_product_id ) {
			$this->update_event_product( $existing_product_id, $post_id );
			return $existing_product_id;
		}

		return $this->create_event_product( $post_id );
	}

	private function create_event_product( int $post_id ): int|WP_Error {
		$event   = get_post( $post_id );
		$title   = $event ? $event->post_title . ' — ' . __( 'Tickets', 'eb4tec' ) : __( 'Event Tickets', 'eb4tec' );
		$cost    = (float) get_post_meta( $post_id, '_EventCost', true );
		$capacity = (int) get_post_meta( $post_id, '_eb4tec_capacity', true );

		$product = new WC_Product_Simple();
		$product->set_name( $title );
		$product->set_status( 'publish' );
		$product->set_regular_price( (string) $cost );
		$product->set_price( (string) $cost );
		$product->set_virtual( true );
		$product->set_sold_individually( false );

		if ( $capacity > 0 ) {
			$product->set_manage_stock( true );
			$product->set_stock_quantity( $capacity );
			$product->set_stock_status( 'instock' );
			$product->set_backorders( 'no' );
		}

		// Assign ticket category if configured.
		$cat_id = (int) get_option( 'eb4tec_woo_category_id', 0 );
		if ( $cat_id ) {
			$product->set_category_ids( [ $cat_id ] );
		}

		$product_id = $product->save();

		if ( ! $product_id ) {
			return new WP_Error( 'eb4tec_wc_product', __( 'Failed to create WooCommerce product.', 'eb4tec' ) );
		}

		update_post_meta( $product_id, '_eb4tec_event_post_id', $post_id );
		update_post_meta( $product_id, '_eb4tec_is_event_ticket', 'yes' );
		update_post_meta( $post_id, '_eb4tec_wp_product_id', $product_id );

		// Transfer featured image.
		$thumbnail_id = get_post_thumbnail_id( $post_id );
		if ( $thumbnail_id ) {
			set_post_thumbnail( $product_id, $thumbnail_id );
		}

		return $product_id;
	}

	private function update_event_product( int $product_id, int $post_id ): void {
		$product = wc_get_product( $product_id );
		if ( ! $product ) {
			return;
		}

		$event    = get_post( $post_id );
		$title    = $event ? $event->post_title . ' — ' . __( 'Tickets', 'eb4tec' ) : $product->get_name();
		$cost     = (float) get_post_meta( $post_id, '_EventCost', true );
		$capacity = (int) get_post_meta( $post_id, '_eb4tec_capacity', true );

		$product->set_name( $title );
		$product->set_regular_price( (string) $cost );
		$product->set_price( (string) $cost );

		if ( $capacity > 0 ) {
			$product->set_manage_stock( true );
			$product->set_stock_quantity( $capacity );
		}

		$product->save();
	}

	// ---------------------------------------------------------------------------
	// Order completed: register attendees in Eventbrite
	// ---------------------------------------------------------------------------

	public function on_order_completed( int $order_id ): void {
		$order = wc_get_order( $order_id );
		if ( ! $order ) {
			return;
		}

		foreach ( $order->get_items() as $item_id => $item ) {
			$product_id = $item->get_product_id();
			if ( get_post_meta( $product_id, '_eb4tec_is_event_ticket', true ) !== 'yes' ) {
				continue;
			}

			$post_id     = (int) get_post_meta( $product_id, '_eb4tec_event_post_id', true );
			$eb_event_id = (string) get_post_meta( $post_id, '_eb4tec_event_id', true );

			if ( ! $post_id || ! $eb_event_id ) {
				continue;
			}

			$capacity = (int) get_post_meta( $post_id, '_eb4tec_capacity', true );
			$class_id_or_error = $this->ticket_manager->ensure_wp_ticket_class( $eb_event_id, $post_id, $capacity );
			if ( is_wp_error( $class_id_or_error ) ) {
				$order->add_order_note( sprintf(
					__( 'EB4TEC: Failed to get ticket class for event %d: %s', 'eb4tec' ),
					$post_id,
					$class_id_or_error->get_error_message()
				) );
				continue;
			}

			$qty          = (int) $item->get_quantity();
			$attendee_ids = [];
			$qr_codes     = [];

			for ( $i = 0; $i < $qty; $i++ ) {
				$attendee_result = $this->register_attendee( $order_id, $order, $eb_event_id, $class_id_or_error, $i );

				if ( is_wp_error( $attendee_result ) ) {
					$order->add_order_note( sprintf(
						__( 'EB4TEC: Failed to register attendee %d for event %d: %s', 'eb4tec' ),
						$i + 1,
						$post_id,
						$attendee_result->get_error_message()
					) );
					continue;
				}

				$attendee_ids[] = $attendee_result;

				// Generate QR code for this attendee.
				$qr_data = $this->qr->get_attendee_qr_data( $attendee_result, (string) $order_id, $eb_event_id );
				$qr_url  = $this->qr->generate( $qr_data );
				if ( ! is_wp_error( $qr_url ) ) {
					$qr_codes[] = [
						'attendee_id' => $attendee_result,
						'qr_url'      => $qr_url,
					];
				}
			}

			// Persist to order meta (append to any already registered for other items).
			$existing_ids   = json_decode( get_post_meta( $order_id, '_eb4tec_attendee_ids', true ) ?: '[]', true );
			$existing_codes = json_decode( get_post_meta( $order_id, '_eb4tec_qr_codes', true ) ?: '[]', true );

			update_post_meta( $order_id, '_eb4tec_attendee_ids', wp_json_encode( array_merge( $existing_ids, $attendee_ids ) ) );
			update_post_meta( $order_id, '_eb4tec_qr_codes', wp_json_encode( array_merge( $existing_codes, $qr_codes ) ) );
			update_post_meta( $order_id, '_eb4tec_event_post_id', $post_id );

			if ( ! empty( $attendee_ids ) ) {
				$order->add_order_note( sprintf(
					__( 'EB4TEC: Registered %d attendee(s) in Eventbrite (IDs: %s).', 'eb4tec' ),
					count( $attendee_ids ),
					implode( ', ', $attendee_ids )
				) );
			}
		}
	}

	public function on_order_refunded( int $order_id ): void {
		$attendee_ids = json_decode( get_post_meta( $order_id, '_eb4tec_attendee_ids', true ) ?: '[]', true );
		if ( empty( $attendee_ids ) ) {
			return;
		}

		// Eventbrite's API does not support cancelling free-class attendees via API.
		// Log a note for manual follow-up.
		$order = wc_get_order( $order_id );
		if ( $order ) {
			$order->add_order_note( sprintf(
				/* translators: list of Eventbrite attendee IDs */
				__( 'EB4TEC: Order refunded/cancelled. Please manually cancel these Eventbrite attendees: %s', 'eb4tec' ),
				implode( ', ', array_map( 'esc_html', $attendee_ids ) )
			) );
		}
	}

	private function register_attendee( int $order_id, WC_Order $order, string $eb_event_id, string $ticket_class_id, int $index ): string|WP_Error {
		$first_name = sanitize_text_field( $order->get_billing_first_name() );
		$last_name  = sanitize_text_field( $order->get_billing_last_name() );
		$email      = sanitize_email( $order->get_billing_email() );

		// Append ticket number if ordering multiple.
		$name = trim( "$first_name $last_name" );
		if ( $index > 0 ) {
			$name .= ' (' . ( $index + 1 ) . ')';
		}

		$result = $this->api->create_attendee( $eb_event_id, [
			'attendee' => [
				'ticket_class_id' => $ticket_class_id,
				'profile'         => [
					'name'  => $name,
					'email' => $email,
				],
				'answers' => [],
			],
		] );

		if ( is_wp_error( $result ) ) {
			return $result;
		}

		$attendee_id = $result['id'] ?? '';
		return $attendee_id ?: new WP_Error( 'eb4tec_no_attendee_id', __( 'Eventbrite did not return an attendee ID.', 'eb4tec' ) );
	}

	// ---------------------------------------------------------------------------
	// Meta boxes
	// ---------------------------------------------------------------------------

	public function add_meta_boxes(): void {
		// Order meta box.
		add_meta_box(
			'eb4tec_order_meta',
			__( 'Eventbrite Attendees', 'eb4tec' ),
			[ $this, 'render_order_meta_box' ],
			wc_get_page_screen_id( 'shop-order' ),
			'side',
			'default'
		);

		// Product meta box.
		add_meta_box(
			'eb4tec_product_meta',
			__( 'Linked Eventbrite Event', 'eb4tec' ),
			[ $this, 'render_product_meta_box' ],
			'product',
			'side',
			'default'
		);
	}

	public function render_order_meta_box( WP_Post $post ): void {
		$attendee_ids = json_decode( get_post_meta( $post->ID, '_eb4tec_attendee_ids', true ) ?: '[]', true );
		$post_id      = (int) get_post_meta( $post->ID, '_eb4tec_event_post_id', true );
		$eb_event_id  = $post_id ? (string) get_post_meta( $post_id, '_eb4tec_event_id', true ) : '';

		if ( empty( $attendee_ids ) ) {
			echo '<p class="description">' . esc_html__( 'No Eventbrite attendees registered for this order.', 'eb4tec' ) . '</p>';
			return;
		}

		echo '<ul style="margin:0;padding:0;list-style:none;">';
		foreach ( $attendee_ids as $id ) {
			echo '<li style="margin-bottom:4px;">';
			if ( $eb_event_id ) {
				printf(
					'<a href="https://www.eventbrite.com/reports?eid=%s" target="_blank">%s</a>',
					esc_attr( $eb_event_id ),
					esc_html( $id )
				);
			} else {
				echo esc_html( $id );
			}
			echo '</li>';
		}
		echo '</ul>';
	}

	public function render_product_meta_box( WP_Post $post ): void {
		wp_nonce_field( 'eb4tec_product_meta_save', '_eb4tec_product_meta_nonce' );

		$event_post_id = (int) get_post_meta( $post->ID, '_eb4tec_event_post_id', true );
		$is_ticket     = get_post_meta( $post->ID, '_eb4tec_is_event_ticket', true ) === 'yes';

		if ( $event_post_id ) {
			$event_title = get_the_title( $event_post_id );
			$edit_url    = get_edit_post_link( $event_post_id );
			echo '<p>';
			printf(
				esc_html__( 'Ticket for: %s', 'eb4tec' ) . ' <a href="%s">%s</a>',
				esc_html( $event_title ),
				esc_url( $edit_url ),
				esc_html__( 'Edit event', 'eb4tec' )
			);
			echo '</p>';
		} else {
			echo '<p class="description">' . esc_html__( 'Not linked to a TEC event.', 'eb4tec' ) . '</p>';
		}

		echo '<p><label><input type="hidden" name="eb4tec_is_event_ticket" value="">';
		echo '<input type="checkbox" name="eb4tec_is_event_ticket" value="yes" ' . checked( $is_ticket, true, false ) . '> ';
		esc_html_e( 'This is an event ticket product', 'eb4tec' );
		echo '</label></p>';
	}

	public function save_product_meta_box( int $post_id ): void {
		if ( get_post_type( $post_id ) !== 'product' ) {
			return;
		}

		if ( ! wp_verify_nonce( $_POST['_eb4tec_product_meta_nonce'] ?? '', 'eb4tec_product_meta_save' ) ) {
			return;
		}

		if ( ! current_user_can( 'edit_post', $post_id ) ) {
			return;
		}

		$is_ticket = ( $_POST['eb4tec_is_event_ticket'] ?? '' ) === 'yes' ? 'yes' : 'no';
		update_post_meta( $post_id, '_eb4tec_is_event_ticket', $is_ticket );
	}

	// ---------------------------------------------------------------------------
	// QR display: thank-you page and email
	// ---------------------------------------------------------------------------

	public function show_qr_on_thankyou( int $order_id ): void {
		if ( ! get_option( 'eb4tec_qr_on_order_page' ) ) {
			return;
		}

		$qr_codes = json_decode( get_post_meta( $order_id, '_eb4tec_qr_codes', true ) ?: '[]', true );
		if ( empty( $qr_codes ) ) {
			return;
		}

		echo '<section class="woocommerce-order-details eb4tec-ticket-qr">';
		echo '<h2 class="woocommerce-order-details__title">' . esc_html__( 'Your Event Tickets', 'eb4tec' ) . '</h2>';
		echo '<p>' . esc_html__( 'Present these QR codes at the event for check-in.', 'eb4tec' ) . '</p>';

		foreach ( $qr_codes as $index => $entry ) {
			$attendee_id = $entry['attendee_id'] ?? '';
			$qr_url      = $entry['qr_url'] ?? '';
			if ( ! $qr_url ) {
				continue;
			}
			echo '<div class="eb4tec-ticket" style="display:inline-block;margin:8px 16px 8px 0;text-align:center;">';
			echo $this->qr->render_qr_html( $qr_url, $attendee_id );
			echo '<small>' . sprintf( esc_html__( 'Ticket %d', 'eb4tec' ), $index + 1 ) . '</small>';
			echo '</div>';
		}

		echo '</section>';
	}

	public function inject_qr_into_email( WC_Order $order, bool $sent_to_admin, bool $plain_text, WC_Email $email ): void {
		if ( $sent_to_admin || $plain_text ) {
			return;
		}

		if ( ! get_option( 'eb4tec_qr_in_email' ) ) {
			return;
		}

		$qr_codes = json_decode( get_post_meta( $order->get_id(), '_eb4tec_qr_codes', true ) ?: '[]', true );
		if ( empty( $qr_codes ) ) {
			return;
		}

		echo '<h2 style="color:#333;font-size:18px;margin-top:24px;">' . esc_html__( 'Your Event Tickets', 'eb4tec' ) . '</h2>';
		echo '<p>' . esc_html__( 'Present these QR codes at the event for check-in.', 'eb4tec' ) . '</p>';

		foreach ( $qr_codes as $index => $entry ) {
			$qr_url      = $entry['qr_url'] ?? '';
			$attendee_id = $entry['attendee_id'] ?? '';
			if ( ! $qr_url ) {
				continue;
			}
			echo '<div style="margin-bottom:16px;">';
			echo '<strong>' . sprintf( esc_html__( 'Ticket %d', 'eb4tec' ), $index + 1 ) . '</strong><br>';
			echo $this->qr->render_qr_html( $qr_url, $attendee_id );
			echo '</div>';
		}
	}
}