<?php

namespace AdPresso\Core\Rest;

use AdPresso\Constants;
use AdPresso\Entities\Ad;
use AdPresso\Groups\GroupRepository;
use AdPresso\Placements\PlacementRepository;
use WP_Error;
use WP_Query;
use WP_REST_Request;
use WP_REST_Response;

/**
 * REST API Controller for the Ad entity.
 */
final class AdController extends AbstractEntityController {

	/**
	 * The base of this controller's route.
	 * @var string
	 */
	protected string $rest_base = 'ads';

	/**
	 * The WordPress post type this controller manages.
	 * @var string
	 */
	protected string $post_type = Constants::POST_TYPE_AD;

	/**
	 * @param WP_REST_Request $request
	 *
	 * @return bool
	 */
	public function get_items_permissions_check( WP_REST_Request $request ): bool {
		return current_user_can( adpresso_get_capability( 'edit_ad' ) );
	}

	/**
	 * @param WP_REST_Request $request
	 *
	 * @return bool
	 */
	public function get_item_permissions_check( WP_REST_Request $request ): bool {
		return current_user_can( 'edit_post', (int) $request['id'] );
	}

	/**
	 * @param WP_REST_Request $request
	 *
	 * @return bool
	 */
	public function create_item_permissions_check( WP_REST_Request $request ): bool {
		return current_user_can( get_post_type_object( $this->post_type )->cap->create_posts );
	}

	/**
	 * @param WP_REST_Request $request
	 *
	 * @return bool
	 */
	public function update_item_permissions_check( WP_REST_Request $request ): bool {
		return current_user_can( 'edit_post', (int) $request['id'] );
	}

	/**
	 * @param WP_REST_Request $request
	 *
	 * @return bool
	 */
	public function delete_item_permissions_check( WP_REST_Request $request ): bool {
		return current_user_can( 'delete_post', (int) $request['id'] );
	}

	/**
	 * Retrieves a collection of ads.
	 *
	 * @param WP_REST_Request $request
	 *
	 * @return WP_REST_Response|WP_Error
	 */
	public function get_items( WP_REST_Request $request ): WP_REST_Response|WP_Error {
		$query_args = $this->build_query_args( $request );
		$query      = new WP_Query( $query_args );

		if ( ! $query->have_posts() ) {
			$response = new WP_REST_Response( [], 200 );
			$response->header( 'X-WP-Total', 0 );
			$response->header( 'X-WP-TotalPages', 0 );
			return $response;
		}

		$ad_ids = wp_list_pluck( $query->posts, 'ID' );
		_prime_post_caches( $ad_ids, false, true );

		$used_in_placements = adpresso_get_placement_repository()->get_used_in_map( $ad_ids, 'ad', [ 'any' ] );
		$used_in_groups     = adpresso_get_group_repository()->find_containing_ads_map( $ad_ids, [ 'publish', 'draft' ] );

		$ad_repository = adpresso_get_ad_repository();
		$items         = [];
		foreach ( $query->posts as $post ) {
			// TODO: if we set process_data flag to false, conditions won't be summarized.
			$ad = $ad_repository->get( $post->ID, true );
			if ( $ad ) {
				$ad->set_used_in_override( $used_in_placements[ $post->ID ] ?? [], $used_in_groups[ $post->ID ] ?? [] );
				// condition_builder_data/edit_ui_sections are only needed by the edit modal (get_item()), not the list.
				$items[] = $ad->prepare_for_rest_response( false );
			}
		}

		$response = new WP_REST_Response( $items, 200 );
		$response->header( 'X-WP-Total', $query->found_posts );
		$response->header( 'X-WP-TotalPages', $query->max_num_pages );

		return $response;
	}

	/**
	 * Retrieves a single ad.
	 *
	 * @param WP_REST_Request $request
	 *
	 * @return WP_REST_Response|WP_Error
	 */
	public function get_item( WP_REST_Request $request ): WP_REST_Response|WP_Error {
		$ad = adpresso_get_ad( (int) $request['id'] );
		if ( ! $ad ) {
			return new WP_Error( 'rest_not_found', __( 'Ad not found.', 'adpresso' ), [ 'status' => 404 ] );
		}

		return new WP_REST_Response( $ad->prepare_for_rest_response(), 200 );
	}

	/**
	 * Creates a single ad.
	 *
	 * @param WP_REST_Request $request
	 *
	 * @return WP_REST_Response|WP_Error
	 */
	public function create_item( WP_REST_Request $request ): WP_REST_Response|WP_Error {
		// Create a new, empty Ad entity to pass to the repository
		$ad = new Ad( null );

		$saved_ad = adpresso_get_ad_repository()->save( $ad, $request->get_params() );

		if ( ! $saved_ad ) {
			return new WP_Error( 'rest_cannot_create', __( 'Failed to create ad.', 'adpresso' ), [ 'status' => 500 ] );
		}

		$skipped = $this->apply_assignment_changes( $request->get_param( 'assignment_changes' ), $saved_ad->get_id() );

		$response = new WP_REST_Response( $this->with_skipped_assignments( $saved_ad->prepare_for_rest_response(), $skipped ), 201 );
		$response->header( 'Location', rest_url( sprintf( '%s/%s/%d', $this->namespace, $this->rest_base, $saved_ad->get_id() ) ) );

		return $response;
	}

	/**
	 * Updates a single ad.
	 *
	 * @param WP_REST_Request $request
	 *
	 * @return WP_REST_Response|WP_Error
	 */
	public function update_item( WP_REST_Request $request ): WP_REST_Response|WP_Error {
		$ad = adpresso_get_ad( (int) $request['id'] );
		if ( ! $ad ) {
			return new WP_Error( 'rest_not_found', __( 'Ad not found.', 'adpresso' ), [ 'status' => 404 ] );
		}
		$ad_id = $ad->get_id();

		$skipped = $this->apply_assignment_changes( $request->get_param( 'assignment_changes' ), $ad_id );

		$saved_ad = adpresso_get_ad_repository()->save( $ad, $request->get_params() );

		if ( ! $saved_ad ) {
			return new WP_Error( 'rest_cannot_update', __( 'Failed to update ad.', 'adpresso' ), [ 'status' => 500 ] );
		}

		return new WP_REST_Response( $this->with_skipped_assignments( $saved_ad->prepare_for_rest_response(), $skipped ), 200 );
	}

	/**
	 * Adds the assignment changes that were not applied to the response data.
	 *
	 * @param mixed $data    Response data.
	 * @param array $skipped Changes that were not applied.
	 *
	 * @return mixed
	 */
	private function with_skipped_assignments( mixed $data, array $skipped ): mixed {
		if ( $skipped && is_array( $data ) ) {
			$data['skipped_assignments'] = $skipped;
		}

		return $data;
	}

	/**
	 * Whether the current user may edit the given post, and it is of one of the given types.
	 *
	 * @param int      $post_id    Target post.
	 * @param string[] $post_types Allowed post types.
	 *
	 * @return bool
	 */
	private function can_edit_target( int $post_id, array $post_types ): bool {
		return $post_id > 0 && in_array( get_post_type( $post_id ), $post_types, true ) && current_user_can( 'edit_post', $post_id );
	}

	/**
	 * Applies group/placement assignment changes sent by the editor modal.
	 *
	 * @param mixed $assignment_changes Raw value of the 'assignment_changes' request param.
	 * @param int   $ad_id
	 *
	 * @return array The changes skipped because the target is not editable for the user (or of the wrong type).
	 */
	private function apply_assignment_changes( mixed $assignment_changes, int $ad_id ): array {
		if ( empty( $assignment_changes ) || ! is_array( $assignment_changes ) ) {
			return [];
		}

		/** @var GroupRepository $group_repository */
		$group_repository     = adpresso_get_group_repository();
		/** @var PlacementRepository $placement_repository */
		$placement_repository = adpresso_get_placement_repository();

		$skipped = [];
		foreach ( $assignment_changes as $change ) {
			if ( ! is_array( $change ) ) {
				continue;
			}
			$action = sanitize_key( $change['action'] ?? '' );

			switch ( $action ) {
				case 'add_to_group':
				case 'remove_from_group':
					$group_id = absint( $change['groupId'] ?? 0 );
					if ( $group_id <= 0 ) {
						break;
					}
					if ( ! $this->can_edit_target( $group_id, [ Constants::POST_TYPE_GROUP ] ) ) {
						$skipped[] = [
							'action'  => $action,
							'groupId' => $group_id,
						];
						break;
					}
					if ( 'add_to_group' === $action ) {
						$group_repository->add_ad_to_group( $group_id, $ad_id );
					} else {
						$group_repository->remove_ad_from_group( $group_id, $ad_id );
					}
					break;

				case 'assign_to_placement':
					$placement_id = absint( $change['placementId'] ?? 0 );
					$context_id   = absint( $change['context']['id'] ?? 0 );
					// The ad's own context has no ID yet when a new ad is saved for the first time.
					if ( $context_id <= 0 && 'group' !== ( $change['context']['type'] ?? '' ) ) {
						$context_id = $ad_id;
					}

					if ( $placement_id <= 0 || $context_id <= 0 ) {
						break;
					}
					// Both the placement and the assigned item (this ad, or a group) must be editable.
					if ( ! $this->can_edit_target( $placement_id, [ Constants::POST_TYPE_PLACEMENT ] )
						|| ! $this->can_edit_target( $context_id, [ Constants::POST_TYPE_AD, Constants::POST_TYPE_GROUP ] ) ) {
						$skipped[] = [
							'action'      => $action,
							'placementId' => $placement_id,
						];
						break;
					}
					$placement_repository->assign_item_to_placement( $placement_id, $context_id );
					break;

				case 'unassign_from_placement':
					$placement_id = absint( $change['placementId'] ?? 0 );
					if ( $placement_id <= 0 ) {
						break;
					}
					if ( ! $this->can_edit_target( $placement_id, [ Constants::POST_TYPE_PLACEMENT ] ) ) {
						$skipped[] = [
							'action'      => $action,
							'placementId' => $placement_id,
						];
						break;
					}
					$placement_repository->unassign_item_from_placement( $placement_id );
					break;
			}
		}

		return $skipped;
	}

	/**
	 * Deletes a single ad.
	 *
	 * @param WP_REST_Request $request
	 *
	 * @return WP_REST_Response|WP_Error
	 */
	public function delete_item( WP_REST_Request $request ): WP_REST_Response|WP_Error {
		$ad = adpresso_get_ad( (int) $request['id'] );
		if ( ! $ad ) {
			return new WP_Error( 'rest_not_found', __( 'Ad not found.', 'adpresso' ), [ 'status' => 404 ] );
		}

		$previous_data = $ad->prepare_for_rest_response();
		$force         = (bool) $request['force'];

		// Same answer as WP core's posts endpoint: trashing twice is a client error, not a server failure.
		if ( ! $force && get_post_status( $ad->get_id() ) === 'trash' ) {
			return new WP_Error( 'rest_already_trashed', __( 'The ad has already been moved to the trash.', 'adpresso' ), [ 'status' => 410 ] );
		}

		$result = adpresso_get_ad_repository()->delete( $ad, $force );

		if ( ! $result ) {
			return new WP_Error( 'rest_cannot_delete', __( 'Failed to delete ad.', 'adpresso' ), [ 'status' => 500 ] );
		}

		return new WP_REST_Response( [ 'deleted' => true, 'previous' => $previous_data ], 200 );
	}

	/**
	 * @return array
	 */
	protected function get_collection_params(): array {
		return [
			'page'     => [ 'type' => 'integer', 'default' => 1, 'sanitize_callback' => 'absint' ],
			'per_page' => [ 'type' => 'integer', 'default' => 20, 'sanitize_callback' => 'absint' ],
			'orderby'  => [ 'type' => 'string', 'default' => 'date', 'sanitize_callback' => 'sanitize_key' ],
			'order'    => [ 'type' => 'string', 'default' => 'desc', 'enum' => [ 'asc', 'desc' ] ],
			's'        => [ 'type' => 'string', 'default' => '', 'sanitize_callback' => 'sanitize_text_field' ],
			'filters'  => [ 'type' => 'object' ],
		];
	}

	/**
	 * @param string $method
	 *
	 * @return array
	 */
	protected function get_endpoint_args_for_item_schema( string $method ): array {
		return [
			'title'     => [ 'type' => 'string', 'sanitize_callback' => 'sanitize_text_field' ],
			'content'   => [ 'type' => 'string' ], // Sanitization happens in repository
			'status'    => [ 'type' => 'string', 'enum' => [ 'publish', 'draft', 'pending', 'private' ] ],
			'meta_data' => [ 'type' => 'object' ],
		];
	}
}