<?php
/**
 * Named-field persistence for booking forms. UPDATE only.
 *
 * @package Bookline
 */

declare( strict_types=1 );

namespace Bookline\Infrastructure\Persistence;

use Bookline\Config\BookingFormPlaces;
use Bookline\Domain\BookingForm\BookingForm;
use Bookline\Domain\BookingForm\BookingFormRepository;
use Bookline\Domain\BookingForm\BookingFormStatus;
use Bookline\Domain\Shared\Uuid;
use DateTimeImmutable;
use DateTimeZone;
use RuntimeException;

/**
 * Lists and mutates booking forms for the admin SPA.
 *
 * @since 0.1.0
 */
final class WpdbBookingFormRepository extends AbstractWpdbRepository implements BookingFormRepository {

	/**
	 * Paginated admin list rows.
	 *
	 * {@inheritDoc}
	 *
	 * @param int $limit  Max rows.
	 * @param int $offset Offset.
	 */
	public function list_for_admin( int $limit, int $offset ): array {
		$limit  = max( 1, min( 100, $limit ) );
		$offset = max( 0, $offset );
		$items  = [];
		foreach ( $this->occupied_by_slot() as $form ) {
			$theme = $form->theme();
			$items[] = [
				'id'         => (int) $form->id(),
				'name'       => $form->name(),
				'slug'       => $form->slug(),
				'status'     => $form->status()->value,
				'step_count' => count( $form->steps() ),
				'accent'     => $theme['accent'] ?? '',
				'updated_at' => $form->updated_at()->format( 'c' ),
			];
		}
		usort(
			$items,
			static function ( array $a, array $b ): int {
				$cmp = (string) $a['name'] <=> (string) $b['name'];
				return 0 !== $cmp ? $cmp : ( (int) $a['id'] <=> (int) $b['id'] );
			}
		);
		$total = count( $items );
		return [
			'items' => array_slice( $items, $offset, $limit ),
			'total' => $total,
		];
	}

	/**
	 * Find a form by id (slot 1–2).
	 *
	 * {@inheritDoc}
	 *
	 * @param int $id Form id.
	 */
	public function find_by_id( int $id ): ?BookingForm {
		return $this->entity_at( $id );
	}

	/**
	 * Find a form by slug.
	 *
	 * {@inheritDoc}
	 *
	 * @param string $slug Unique slug.
	 */
	public function find_by_slug( string $slug ): ?BookingForm {
		$slug = trim( $slug );
		if ( '' === $slug ) {
			return null;
		}
		foreach ( $this->occupied_by_slot() as $form ) {
			if ( $form->slug() === $slug ) {
				return $form;
			}
		}
		return null;
	}

	/**
	 * Persist into a named form field.
	 *
	 * {@inheritDoc}
	 *
	 * @param BookingForm $form Form entity.
	 */
	public function save( BookingForm $form ): void {
		$json = $this->encode_payload( $this->to_row( $form ) );
		if ( null === $form->id() ) {
			$slot = BookingFormPlaces::from_occupied( $this->occupied_by_slot() )->place( $form );
			$form->assign_id( $slot );
			$this->slots()->write( $slot, $json );
			return;
		}
		$this->slots()->write( (int) $form->id(), $json );
	}

	/**
	 * Clear a named form field.
	 *
	 * {@inheritDoc}
	 *
	 * @param int $id Form id.
	 */
	public function delete( int $id ): void {
		if ( $id <= 0 ) {
			return;
		}
		$this->slots()->write( $id, null );
	}

	/**
	 * Stored forms.
	 *
	 * {@inheritDoc}
	 */
	public function count_stored(): int {
		return count( $this->occupied_by_slot() );
	}

	/**
	 * Occupied named fields keyed by slot.
	 *
	 * @return array<int, BookingForm>
	 */
	private function occupied_by_slot(): array {
		$out   = [];
		$store = $this->slots();
		$count = $store->field_count();
		for ( $slot = 1; $slot <= $count; $slot++ ) {
			$entity = $this->entity_at( $slot );
			if ( null !== $entity ) {
				$out[ $slot ] = $entity;
			}
		}
		return $out;
	}

	/**
	 * Hydrate one named field.
	 *
	 * @param int $slot Field number.
	 */
	private function entity_at( int $slot ): ?BookingForm {
		$json = $this->slots()->payload( $slot );
		if ( null === $json ) {
			return null;
		}
		$decoded = json_decode( $json, true );
		if ( ! is_array( $decoded ) ) {
			return null;
		}
		$decoded['id'] = $slot;
		return $this->hydrate( $decoded );
	}

	/**
	 * Slot store for this catalogue table.
	 */
	private function slots(): CatalogueSlotStore {
		return new CatalogueSlotStore( $this->db, $this->table( 'booking_forms' ), 'form', 2 );
	}

	/**
	 * Encode a payload as JSON.
	 *
	 * @param array<string, mixed> $row Payload.
	 *
	 * @throws RuntimeException When encoding fails.
	 */
	private function encode_payload( array $row ): string {
		$json = wp_json_encode( $row );
		if ( false === $json ) {
			throw new RuntimeException( 'Failed to encode a booking-form field.' );
		}
		return $json;
	}

	/**
	 * Map an entity to a stored payload.
	 *
	 * @param BookingForm $form Entity.
	 * @return array<string, mixed>
	 */
	private function to_row( BookingForm $form ): array {
		return [
			'uuid'         => $form->uuid()->to_string(),
			'name'         => $form->name(),
			'slug'         => $form->slug(),
			'steps'        => $form->steps(),
			'service_ids'  => $form->service_ids(),
			'agent_ids'    => $form->agent_ids(),
			'location_ids' => $form->location_ids(),
			'category_ids' => $form->category_ids(),
			'settings'     => $form->settings(),
			'theme'        => $form->theme(),
			'status'       => $form->status()->value,
			'created_at'   => $this->format_datetime( $form->created_at() ),
			'updated_at'   => $this->format_datetime( $form->updated_at() ),
		];
	}

	/**
	 * Hydrate a stored payload.
	 *
	 * @param array<string, mixed> $row Row.
	 */
	private function hydrate( array $row ): BookingForm {
		$created = (string) ( $row['created_at'] ?? '' );
		$updated = (string) ( $row['updated_at'] ?? '' );
		$steps   = $row['steps'] ?? null;
		$theme   = $row['theme'] ?? null;

		return new BookingForm(
			(int) ( $row['id'] ?? 0 ),
			new Uuid( (string) ( $row['uuid'] ?? '' ) ),
			(string) ( $row['name'] ?? '' ),
			(string) ( $row['slug'] ?? '' ),
			is_array( $steps ) ? $this->string_list( $steps ) : $this->decode_string_list( is_string( $steps ) ? $steps : null ),
			$this->optional_id_list( $row['service_ids'] ?? null ),
			$this->optional_id_list( $row['agent_ids'] ?? null ),
			$this->optional_id_list( $row['location_ids'] ?? null ),
			$this->optional_id_list( $row['category_ids'] ?? null ),
			$this->decode_settings_value( $row['settings'] ?? null ),
			is_array( $theme ) ? $this->theme_from_array( $theme ) : $this->decode_theme( is_string( $theme ) ? $theme : null ),
			BookingFormStatus::from( (string) ( $row['status'] ?? 'inactive' ) ),
			'' !== $created
				? new DateTimeImmutable( $created, new DateTimeZone( 'UTC' ) )
				: new DateTimeImmutable( 'now', new DateTimeZone( 'UTC' ) ),
			'' !== $updated
				? new DateTimeImmutable( $updated, new DateTimeZone( 'UTC' ) )
				: new DateTimeImmutable( 'now', new DateTimeZone( 'UTC' ) ),
		);
	}

	/**
	 * String values from a decoded list.
	 *
	 * @param list<mixed> $decoded Decoded steps.
	 * @return list<string>
	 */
	private function string_list( array $decoded ): array {
		$out = [];
		foreach ( $decoded as $item ) {
			if ( is_string( $item ) && '' !== $item ) {
				$out[] = $item;
			}
		}
		return $out;
	}

	/**
	 * Decode a JSON string list.
	 *
	 * @param string|null $json JSON.
	 * @return list<string>
	 */
	private function decode_string_list( ?string $json ): array {
		if ( null === $json || '' === $json ) {
			return [];
		}
		$decoded = json_decode( $json, true );
		if ( ! is_array( $decoded ) ) {
			return [];
		}
		return $this->string_list( $decoded );
	}

	/**
	 * Decode settings JSON or array.
	 *
	 * @param mixed $value Stored settings.
	 * @return array<string, mixed>
	 */
	private function decode_settings_value( mixed $value ): array {
		if ( is_array( $value ) ) {
			return $value;
		}
		if ( ! is_string( $value ) || '' === $value ) {
			return [];
		}
		$decoded = json_decode( $value, true );
		return is_array( $decoded ) ? $decoded : [];
	}

	/**
	 * Decode theme JSON with defaults.
	 *
	 * @param string|null $json JSON.
	 * @return array<string, string>
	 */
	private function decode_theme( ?string $json ): array {
		if ( null === $json || '' === $json ) {
			return BookingForm::default_theme();
		}
		$decoded = json_decode( $json, true );
		if ( ! is_array( $decoded ) ) {
			return BookingForm::default_theme();
		}
		return $this->theme_from_array( $decoded );
	}

	/**
	 * Merge a theme payload onto the defaults.
	 *
	 * @param array<string, mixed> $decoded Theme payload.
	 * @return array<string, string>
	 */
	private function theme_from_array( array $decoded ): array {
		$theme = BookingForm::default_theme();
		foreach ( array_keys( $theme ) as $key ) {
			if ( isset( $decoded[ $key ] ) && is_string( $decoded[ $key ] ) ) {
				$theme[ $key ] = $decoded[ $key ];
			}
		}
		return $theme;
	}

	/**
	 * Optional id list from JSON or array.
	 *
	 * @param mixed $value Stored ids.
	 * @return list<int>|null
	 */
	private function optional_id_list( mixed $value ): ?array {
		if ( null === $value || '' === $value ) {
			return null;
		}
		if ( is_array( $value ) ) {
			$out = [];
			foreach ( $value as $id ) {
				$out[] = (int) $id;
			}
			return $out;
		}
		if ( ! is_string( $value ) ) {
			return null;
		}
		$decoded = json_decode( $value, true );
		if ( ! is_array( $decoded ) ) {
			return null;
		}
		$out = [];
		foreach ( $decoded as $id ) {
			$out[] = (int) $id;
		}
		return $out;
	}
}