<?php
declare(strict_types=1);

namespace Unsupervised\Schedular\Policy;

use Unsupervised\Schedular\Auth\RoleManager;

class PolicyEndpoint {

	public function __construct(
		private PolicyRepository $policies,
		private PolicyVersionRepository $versions,
		private PolicyService $service,
	) {}

	public function registerRoutes( string $route_namespace ): void {
		register_rest_route(
			$route_namespace,
			'/policies',
			[
				[
					'methods'             => \WP_REST_Server::READABLE,
					'callback'            => [ $this, 'index' ],
					'permission_callback' => [ $this, 'canBook' ],
				],
				[
					'methods'             => \WP_REST_Server::CREATABLE,
					'callback'            => [ $this, 'create' ],
					'permission_callback' => [ $this, 'canManage' ],
				],
			]
		);

		register_rest_route(
			$route_namespace,
			'/policies/(?P<id>\d+)/versions',
			[
				[
					'methods'             => \WP_REST_Server::CREATABLE,
					'callback'            => [ $this, 'addVersion' ],
					'permission_callback' => [ $this, 'canManage' ],
				],
			]
		);

		register_rest_route(
			$route_namespace,
			'/policies/(?P<id>\d+)/versions/(?P<vid>\d+)',
			[
				[
					'methods'             => \WP_REST_Server::EDITABLE,
					'callback'            => [ $this, 'updateVersion' ],
					'permission_callback' => [ $this, 'canManage' ],
				],
			]
		);

		register_rest_route(
			$route_namespace,
			'/policies/(?P<id>\d+)/versions/(?P<vid>\d+)/publish',
			[
				[
					'methods'             => \WP_REST_Server::CREATABLE,
					'callback'            => [ $this, 'publish' ],
					'permission_callback' => [ $this, 'canManage' ],
				],
			]
		);
	}

	/**
	 * Public: the current published version of every policy (the registration
	 * gate). Pass `?scope=signup|booking` to limit to that gate (includes
	 * `both`-scoped policies).
	 */
	public function index( \WP_REST_Request $request ): \WP_REST_Response {
		$scope    = (string) $request->get_param( 'scope' );
		$policies = in_array( $scope, [ Policy::SCOPE_SIGNUP, Policy::SCOPE_BOOKING ], true )
			? $this->policies->findForScope( $scope )
			: $this->policies->findAll();

		$out = [];

		foreach ( $policies as $policy ) {
			if ( null === $policy->currentVersionId ) {
				continue;
			}

			$version = $this->versions->findById( $policy->currentVersionId );
			if ( null === $version || ! $version->isPublished() ) {
				continue;
			}

			$out[] = [
				'id'                => $policy->id,
				'title'             => $policy->title,
				'slug'              => $policy->slug,
				'policy_version_id' => $version->id,
				'version_number'    => $version->versionNumber,
				// Bodies are kses'd on every write path, but the booking JS renders
				// this HTML raw — sanitise at output too so a missed write path can
				// never become stored XSS.
				'body'              => wp_kses_post( (string) $version->body ),
			];
		}

		return new \WP_REST_Response( $out, 200 );
	}

	public function create( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
		$title = sanitize_text_field( (string) $request->get_param( 'title' ) );
		if ( '' === $title ) {
			return $this->invalid( __( 'A policy title is required.', 'unsupervised-schedular' ) );
		}

		$slugParam = sanitize_text_field( (string) $request->get_param( 'slug' ) );
		$slug      = sanitize_title( '' !== $slugParam ? $slugParam : $title );
		if ( '' === $slug ) {
			return $this->invalid( __( 'A valid policy slug is required.', 'unsupervised-schedular' ) );
		}

		if ( null !== $this->policies->findBySlug( $slug ) ) {
			return new \WP_Error( 'duplicate_slug', __( 'A policy with that slug already exists.', 'unsupervised-schedular' ), [ 'status' => 409 ] );
		}

		$scope = (string) ( $request->get_param( 'acceptance_scope' ) ?? Policy::SCOPE_BOOKING );
		if ( ! in_array( $scope, Policy::VALID_SCOPES, true ) ) {
			return $this->invalid( __( 'Invalid acceptance scope.', 'unsupervised-schedular' ) );
		}

		$id = $this->service->createPolicy( $title, $slug, $scope );

		return new \WP_REST_Response( [ 'id' => $id ], 201 );
	}

	public function addVersion( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
		$policy = $this->policies->findById( absint( $request->get_param( 'id' ) ) );
		if ( null === $policy ) {
			return $this->notFound();
		}

		$body = wp_kses_post( (string) $request->get_param( 'body' ) );
		$id   = $this->service->addDraftVersion( (int) $policy->id, $body );

		return new \WP_REST_Response( [ 'id' => $id ], 201 );
	}

	public function updateVersion( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
		$version = $this->loadVersionForPolicy( $request );
		if ( $version instanceof \WP_Error ) {
			return $version;
		}

		if ( PolicyVersion::STATUS_DRAFT !== $version->status ) {
			return $this->invalid( __( 'Only draft versions can be edited.', 'unsupervised-schedular' ) );
		}

		$body = wp_kses_post( (string) $request->get_param( 'body' ) );
		$this->versions->updateBody( (int) $version->id, $body );

		return new \WP_REST_Response(
			[
				'id'   => $version->id,
				'body' => $body,
			],
			200
		);
	}

	public function publish( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
		$version = $this->loadVersionForPolicy( $request );
		if ( $version instanceof \WP_Error ) {
			return $version;
		}

		$this->service->publishVersion( (int) $request->get_param( 'id' ), (int) $version->id );

		return new \WP_REST_Response(
			[
				'id'     => $version->id,
				'status' => PolicyVersion::STATUS_PUBLISHED,
			],
			200
		);
	}

	public function canManage(): bool {
		return is_user_logged_in() && current_user_can( RoleManager::CAP_MANAGE_POLICIES );
	}

	/**
	 * The published-policy listing is only read by the logged-in student
	 * booking/enrolment flow (the signup gate renders its policies server-side, not
	 * via this endpoint), so reading it requires the booking capability — there is
	 * no anonymous consumer.
	 */
	public function canBook(): bool {
		return is_user_logged_in() && current_user_can( RoleManager::CAP_BOOK_LESSON );
	}

	/**
	 * Load the version named in the route and confirm it belongs to the policy.
	 */
	private function loadVersionForPolicy( \WP_REST_Request $request ): PolicyVersion|\WP_Error {
		$policyId = absint( $request->get_param( 'id' ) );
		$version  = $this->versions->findById( absint( $request->get_param( 'vid' ) ) );

		if ( null === $version || $version->policyId !== $policyId ) {
			return $this->notFound();
		}

		return $version;
	}

	private function notFound(): \WP_Error {
		return new \WP_Error( 'not_found', __( 'Policy or version not found.', 'unsupervised-schedular' ), [ 'status' => 404 ] );
	}

	private function invalid( string $message ): \WP_Error {
		return new \WP_Error( 'invalid_policy', $message, [ 'status' => 400 ] );
	}
}