<?php
/**
 * Submission pipeline.
 *
 * @package FormPilot
 * @since   1.0.0
 */

declare( strict_types = 1 );

namespace FormPilot\Submissions;

use FormPilot\Database\Repositories\FieldRepository;
use FormPilot\Database\Repositories\FormRepository;
use FormPilot\Database\Repositories\SubmissionRepository;
use FormPilot\Models\Form;
use FormPilot\Security\Request;
use FormPilot\Security\SpamGuard;
use WP_Error;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Runs a submission from raw values to a stored entry.
 *
 * The AJAX endpoint and the REST endpoint both call this, so spam screening,
 * validation and storage behave identically no matter how the submission
 * arrived.
 *
 * @since 1.0.0
 */
final class SubmissionProcessor {

	/**
	 * Constructor.
	 *
	 * @param FormRepository       $forms       Form repository.
	 * @param FieldRepository      $fields      Field repository.
	 * @param SubmissionRepository $submissions Submission repository.
	 * @param Validator            $validator   Submission validator.
	 * @param SpamGuard            $guard       Spam guard.
	 */
	public function __construct(
		private FormRepository $forms,
		private FieldRepository $fields,
		private SubmissionRepository $submissions,
		private Validator $validator,
		private SpamGuard $guard
	) {}

	/**
	 * Screens, validates and stores a submission.
	 *
	 * @param int                        $form_id Form being submitted.
	 * @param array<string, mixed>       $values  Unslashed values keyed by field key.
	 * @param array<string, mixed>       $context Request metadata stored with the entry.
	 * @param array<string, string>|null $signals Optional. Spam signals, see SpamGuard::signals().
	 *                                            Default read from the request.
	 *
	 * @return int|WP_Error The new submission ID, or the reason it was refused.
	 */
	public function process( int $form_id, array $values, array $context = array(), ?array $signals = null ): int|WP_Error {
		$form = $form_id > 0 ? $this->forms->find( $form_id ) : null;

		if ( ! $form instanceof Form || ! $form->is_published() ) {
			return new WP_Error(
				'formpilot_unknown_form',
				__( 'This form is no longer available.', 'devplugins-custom-form-builder' ),
				array( 'status' => 404 )
			);
		}

		$rejection = $this->guard->check( $form, $values, $signals );

		if ( $rejection instanceof WP_Error ) {
			$code = (string) $rejection->get_error_code();

			/*
			 * An attempt refused as spam counts against the rate limit. Validation
			 * failures deliberately do not: mistyping an email address is not abuse,
			 * and holding it against the visitor turns a typo into a lockout.
			 */
			if ( 'formpilot_spam' === $code ) {
				$this->guard->record_rejection( $form->id() );
			}

			/*
			 * The status describes what happened. Answering 429 to everything told a
			 * well behaved client that a cross-origin post or a blocklisted address
			 * was a rate limit and invited it to retry something that can never
			 * succeed. Only the two genuinely time-based refusals say 429.
			 *
			 * `add_data()` replaces the bag rather than adding to it, which used to
			 * destroy the score `formpilot_spam` carries, so the existing data is merged.
			 */
			$status = match ( $code ) {
				'formpilot_throttled', 'formpilot_rate_limited' => 429,
				'formpilot_cross_origin', 'formpilot_blocked'   => 403,
				default                             => 422,
			};

			$data = $rejection->get_error_data( $code );
			$data = is_array( $data ) ? $data : array();

			$rejection->add_data( array_merge( $data, array( 'status' => $status ) ), $code );

			return $rejection;
		}

		$fields = $this->fields->for_form( $form->id() );

		if ( array() === $fields ) {
			return new WP_Error(
				'formpilot_empty_form',
				__( 'This form has no fields.', 'devplugins-custom-form-builder' ),
				array( 'status' => 400 )
			);
		}

		$result = $this->validator->validate( $fields, $values );

		if ( ! $result->is_valid() ) {
			return new WP_Error(
				'formpilot_validation_failed',
				__( 'Please check the highlighted fields and try again.', 'devplugins-custom-form-builder' ),
				array(
					'status' => 422,
					'errors' => $result->errors(),
				)
			);
		}

		$entries  = array();
		$accepted = $result->values();

		foreach ( $fields as $field ) {
			$key = $field->field_key();

			if ( ! array_key_exists( $key, $accepted ) ) {
				continue;
			}

			$entries[] = array(
				'field_id' => $field->id(),
				'key'      => $key,
				'value'    => $accepted[ $key ],
			);
		}

		$submission_id = $this->submissions->create( $form->id(), $entries, $context );

		if ( 0 === $submission_id ) {
			// The files were written during validation; nothing points at them now.
			$this->validator->discard_stored_uploads( $fields, $accepted );

			return new WP_Error(
				'formpilot_storage_failed',
				__( 'Your submission could not be saved. Please try again.', 'devplugins-custom-form-builder' ),
				array( 'status' => 500 )
			);
		}

		$this->forms->increment_submission_count( $form->id() );
		$this->guard->record( $form->id() );

		return $submission_id;
	}

	/**
	 * Returns the form a submission targets.
	 *
	 * @param int $form_id Form ID.
	 *
	 * @return Form|null The form, or null when it cannot receive submissions.
	 */
	public function form( int $form_id ): ?Form {
		$form = $form_id > 0 ? $this->forms->find( $form_id ) : null;

		return $form instanceof Form && $form->is_published() ? $form : null;
	}

	/**
	 * Collects the request metadata stored with a submission.
	 *
	 * @param int $post_id Optional. Post holding the form. Default 0.
	 *
	 * @return array<string, mixed> The context.
	 */
	public function context( int $post_id = 0 ): array {
		$user_agent = Request::server( 'HTTP_USER_AGENT' );
		$address    = Request::ip();

		return array(
			'user_id'    => get_current_user_id(),
			/** This filter is documented in src/Frontend/SubmissionHandler.php */
			'ip_address' => (string) apply_filters( 'formpilot_submission_ip', wp_privacy_anonymize_ip( $address ), $address ),
			'user_agent' => $user_agent,
			'referer'    => (string) wp_get_referer(),
			'post_id'    => $post_id,
		);
	}
}