<?php
/**
 * REST endpoints for the admin app. Everything requires manage_woocommerce (shop managers).
 *
 * @package CNWS\Coupons
 */

namespace CNWS\Coupons\Admin;

use CNWS\Coupons\Campaign;
use CNWS\Coupons\CampaignRepository;
use CNWS\Coupons\CampaignStats;
use CNWS\Coupons\CategoryRepository;
use CNWS\Coupons\CodeRepository;
use CNWS\Coupons\Dashboard;
use CNWS\Coupons\Issuer;
use WP_Error;
use WP_REST_Request;
use WP_REST_Response;
use WP_REST_Server;

defined( 'ABSPATH' ) || exit;

final class RestController {

	public const NAMESPACE = 'cnwscoupons/v1';

	/**
	 * Most addresses handled in one issue request; the app sends bigger lists in chunks.
	 */
	public const ISSUE_BATCH = 500;

	public function __construct(
		private CampaignRepository $campaigns,
		private CategoryRepository $categories,
		private CodeRepository $codes,
		private Issuer $issuer,
		private CampaignStats $stats,
		private Promotions $promotions,
		private Dashboard $dashboard
	) {}

	public function register(): void {
		add_action( 'rest_api_init', array( $this, 'routes' ) );
	}

	public function routes(): void {
		$id = '/campaigns/(?P<id>\d+)';

		$this->route( '/campaigns', WP_REST_Server::READABLE, 'list_campaigns' );
		$this->route( '/campaigns', WP_REST_Server::CREATABLE, 'create_campaign' );
		$this->route( $id, WP_REST_Server::READABLE, 'get_campaign' );
		$this->route( $id, WP_REST_Server::EDITABLE, 'update_campaign' );
		$this->route( $id . '/status', WP_REST_Server::CREATABLE, 'set_status' );
		$this->route( $id . '/codes', WP_REST_Server::READABLE, 'list_codes' );
		$this->route( $id . '/issue', WP_REST_Server::CREATABLE, 'issue_codes' );
		$this->route( '/categories', WP_REST_Server::READABLE, 'list_categories' );
		$this->route( '/categories', WP_REST_Server::CREATABLE, 'create_category' );
		$this->route( '/dashboard', WP_REST_Server::READABLE, 'dashboard' );
		$this->route( '/lookup', WP_REST_Server::READABLE, 'lookup' );
		$this->route( '/code-available', WP_REST_Server::READABLE, 'code_available' );
		$this->route( '/promotions/(?P<key>[a-z_]+)/dismiss', WP_REST_Server::CREATABLE, 'dismiss_promotion' );
	}

	public function can_manage(): bool {
		return current_user_can( 'manage_woocommerce' );
	}

	public function list_campaigns(): WP_REST_Response {
		$stats      = $this->stats->all();
		$categories = $this->categories->all();
		$list       = array();

		foreach ( $this->campaigns->all() as $campaign ) {
			$list[] = $this->campaign_data( $campaign, $categories, $stats[ $campaign->id ] ?? CampaignStats::empty() );
		}

		return new WP_REST_Response( $list );
	}

	/**
	 * @param WP_REST_Request $request Request.
	 */
	public function get_campaign( WP_REST_Request $request ) {
		$campaign = $this->campaigns->find( (int) $request['id'] );

		if ( ! $campaign ) {
			return $this->not_found();
		}

		$data                = $this->campaign_data( $campaign, $this->categories->all(), $this->stats->for_campaign( $campaign->id ) );
		$data['labels']      = $this->labels( $campaign );
		$data['issue_batch'] = self::ISSUE_BATCH;

		return new WP_REST_Response( $data );
	}

	/**
	 * @param WP_REST_Request $request Request with the campaign as JSON.
	 */
	public function create_campaign( WP_REST_Request $request ) {
		$input  = $this->input( $request );
		$result = $this->campaigns->create( $input );

		if ( $result instanceof WP_Error ) {
			return $this->error( $result );
		}

		$this->save_extensions( $result->id, $input );

		return $this->get_campaign( $this->with_id( $result->id ) );
	}

	/**
	 * @param WP_REST_Request $request Request with the campaign as JSON.
	 */
	public function update_campaign( WP_REST_Request $request ) {
		$input  = $this->input( $request );
		$result = $this->campaigns->update( (int) $request['id'], $input );

		if ( $result instanceof WP_Error ) {
			return $this->error( $result );
		}

		$this->save_extensions( $result->id, $input );

		return $this->get_campaign( $this->with_id( $result->id ) );
	}

	/**
	 * @param WP_REST_Request $request Request with status 'active' or 'ended'.
	 */
	public function set_status( WP_REST_Request $request ) {
		if ( ! $this->campaigns->set_status( (int) $request['id'], sanitize_key( (string) $request['status'] ) ) ) {
			return $this->not_found();
		}

		return $this->get_campaign( $this->with_id( (int) $request['id'] ) );
	}

	/**
	 * @param WP_REST_Request $request Request.
	 */
	public function list_codes( WP_REST_Request $request ) {
		if ( ! $this->campaigns->find( (int) $request['id'] ) ) {
			return $this->not_found();
		}

		$codes = array();

		foreach ( $this->codes->for_campaign( (int) $request['id'], 200 ) as $row ) {
			$codes[] = array(
				'code'       => (string) $row->code,
				'email'      => (string) $row->email,
				'uses'       => (int) $row->uses,
				'expires_at' => $row->expires_at ? get_date_from_gmt( (string) $row->expires_at, 'Y-m-d' ) : '',
				'created_at' => get_date_from_gmt( (string) $row->created_at, 'Y-m-d' ),
				'source'     => (string) $row->source,
			);
		}

		return new WP_REST_Response( $codes );
	}

	/**
	 * Issue personal codes to a list of addresses (separated by new lines, commas, semicolons or spaces).
	 *
	 * @param WP_REST_Request $request Request with 'emails'.
	 */
	public function issue_codes( WP_REST_Request $request ) {
		$campaign = $this->campaigns->find( (int) $request['id'] );

		if ( ! $campaign ) {
			return $this->not_found();
		}

		$emails = self::split_emails( (string) $request['emails'] );

		if ( count( $emails ) > self::ISSUE_BATCH ) {
			return new WP_Error( 'cnwscoupons_batch', __( 'Too many addresses in one request.', 'webstyle-coupons' ), array( 'status' => 400 ) );
		}

		$results = array();

		foreach ( $emails as $email ) {
			$code      = $this->issuer->issue( $campaign->slug, $email, 'admin' );
			$results[] = array(
				'email' => $email,
				'code'  => is_string( $code ) ? $code : '',
				'error' => is_string( $code ) ? '' : $code->get_error_message(),
			);
		}

		return new WP_REST_Response( $results );
	}

	public function list_categories(): WP_REST_Response {
		$counts = array();

		foreach ( $this->campaigns->all() as $campaign ) {
			$counts[ $campaign->category_id ] = ( $counts[ $campaign->category_id ] ?? 0 ) + 1;
		}

		$list = array();

		foreach ( $this->categories->all() as $id => $name ) {
			$list[] = array(
				'id'        => $id,
				'name'      => $name,
				'campaigns' => $counts[ $id ] ?? 0,
			);
		}

		return new WP_REST_Response( $list );
	}

	/**
	 * @param WP_REST_Request $request Request with 'name'.
	 */
	public function create_category( WP_REST_Request $request ) {
		$id = $this->categories->find_or_create( (string) $request['name'] );

		return $id ? $this->list_categories() : new WP_Error( 'cnwscoupons_category_name', __( 'The category needs a name.', 'webstyle-coupons' ), array( 'status' => 400 ) );
	}

	/**
	 * Search products, product categories, tags or attribute values for the restriction pickers.
	 *
	 * @param WP_REST_Request $request Request with 'type' and 'search'.
	 */
	public function lookup( WP_REST_Request $request ): WP_REST_Response {
		$search = sanitize_text_field( (string) $request['search'] );
		$page   = max( 1, absint( $request['page'] ) );

		switch ( sanitize_key( (string) $request['type'] ) ) {
			case 'products':
				return new WP_REST_Response( Lookup::products( $search, $page ) );
			case 'categories':
				return new WP_REST_Response( Lookup::terms( 'product_cat', $search, $page ) );
			case 'tags':
				return new WP_REST_Response( Lookup::terms( 'product_tag', $search, $page ) );
			case 'attributes':
				return new WP_REST_Response( Lookup::attribute_terms( $search, $page ) );
		}

		return new WP_REST_Response(
			array(
				'items' => array(),
				'more'  => false,
			)
		);
	}

	/**
	 * @param WP_REST_Request $request Request with 'code'.
	 */
	public function code_available( WP_REST_Request $request ): WP_REST_Response {
		$code = CampaignRepository::normalize_shared_code( (string) $request['code'] );

		return new WP_REST_Response(
			array(
				'code'      => $code,
				'valid'     => '' !== $code,
				'available' => '' !== $code && $this->campaigns->code_available( $code ),
			)
		);
	}

	/**
	 * @param WP_REST_Request $request period (week, month, 3months, custom), from, to, category, campaign.
	 */
	public function dashboard( WP_REST_Request $request ) {
		$report = $this->dashboard->filtered(
			sanitize_key( (string) $request['period'] ),
			sanitize_text_field( (string) $request['from'] ),
			sanitize_text_field( (string) $request['to'] ),
			(int) $request['category'],
			absint( $request['campaign'] )
		);

		if ( null === $report ) {
			return new WP_Error( 'cnwscoupons_period', __( 'Choose a valid period of at most two years.', 'webstyle-coupons' ), array( 'status' => 400 ) );
		}

		return new WP_REST_Response( $report );
	}

	/**
	 * @param WP_REST_Request $request Request with the promotion key.
	 */
	public function dismiss_promotion( WP_REST_Request $request ): WP_REST_Response {
		$this->promotions->dismiss( (string) $request['key'] );

		return new WP_REST_Response( $this->promotions->visible() );
	}

	/**
	 * Campaign as the app sees it.
	 *
	 * @param Campaign           $campaign   Campaign.
	 * @param array<int, string> $categories Category names by ID.
	 * @param array              $stats      CampaignStats row.
	 */
	private function campaign_data( Campaign $campaign, array $categories, array $stats ): array {
		$shared = $campaign->is_shared() ? $this->codes->find_for( $campaign->id, '' ) : null;

		return array(
			'id'               => $campaign->id,
			'slug'             => $campaign->slug,
			'name'             => $campaign->name,
			'category'         => $categories[ $campaign->category_id ] ?? '',
			'category_id'      => $campaign->category_id,
			'type'             => $campaign->type,
			'discount_type'    => $campaign->discount_type,
			'amount'           => $campaign->amount,
			'starts_on'        => $campaign->starts_on,
			'expires_on'       => $campaign->expires_on,
			'valid_days'       => $campaign->valid_days,
			'code_prefix'      => $campaign->code_prefix,
			'max_codes'        => $campaign->max_codes,
			'uses_per_code'    => $campaign->uses_per_code,
			'max_redemptions'  => $campaign->max_redemptions,
			'max_per_email'    => $campaign->max_per_email,
			'email_restricted' => $campaign->email_restricted,
			'restrictions'     => $campaign->restrictions->to_array(),
			'extensions'       => (object) array_intersect_key( $campaign->extensions, self::extension_sanitizers() ),
			'status'           => $campaign->status,
			'shared_code'      => $shared ? (string) $shared->code : '',
			'shared_uses'      => $shared ? (int) $shared->uses : 0,
			'stats'            => $stats,
		);
	}

	/**
	 * Names for the IDs in a campaign's restrictions, so the pickers can show them.
	 *
	 * @param Campaign $campaign Campaign.
	 * @return array<string, array<int, string>>
	 */
	private function labels( Campaign $campaign ): array {
		$lists = $campaign->restrictions->lists;
		$ids   = static fn( string $key ) => array_merge( $lists[ $key ]['include'], $lists[ $key ]['exclude'] );

		return array(
			'products'   => Lookup::product_labels( $ids( 'products' ) ),
			'categories' => Lookup::term_labels( $ids( 'categories' ) ),
			'tags'       => Lookup::term_labels( $ids( 'tags' ) ),
			'attributes' => Lookup::term_labels( $ids( 'attributes' ), true ),
		);
	}

	/**
	 * Add-ons that store settings on a campaign: key => callback that cleans the submitted settings
	 * and returns them as an array. Only registered keys are saved or shown to the app.
	 *
	 * @return array<string, callable>
	 */
	private static function extension_sanitizers(): array {
		$sanitizers = apply_filters( 'cnwscoupons_extension_sanitizers', array() );

		return is_array( $sanitizers ) ? array_filter( $sanitizers, 'is_callable' ) : array();
	}

	/**
	 * @param int   $campaign_id Campaign ID.
	 * @param array $input       Submitted campaign with an 'extensions' object.
	 */
	private function save_extensions( int $campaign_id, array $input ): void {
		$submitted = isset( $input['extensions'] ) && is_array( $input['extensions'] ) ? $input['extensions'] : array();

		foreach ( self::extension_sanitizers() as $key => $sanitize ) {
			if ( isset( $submitted[ $key ] ) && is_array( $submitted[ $key ] ) ) {
				$clean = call_user_func( $sanitize, $submitted[ $key ] );
				$this->campaigns->save_extension( $campaign_id, (string) $key, is_array( $clean ) ? $clean : array() );
			}
		}
	}

	/**
	 * @param WP_REST_Request $request Request with JSON body.
	 */
	private function input( WP_REST_Request $request ): array {
		$data = $request->get_json_params();

		return is_array( $data ) ? $data : array();
	}

	private function with_id( int $id ): WP_REST_Request {
		$request = new WP_REST_Request( 'GET' );
		$request->set_url_params( array( 'id' => $id ) );

		return $request;
	}

	/**
	 * Split a pasted list of addresses, dropping duplicates.
	 *
	 * @param string $text Addresses separated by new lines, commas, semicolons or spaces.
	 * @return string[]
	 */
	public static function split_emails( string $text ): array {
		$parts = preg_split( '/[\s,;]+/', strtolower( $text ) );

		return array_values( array_unique( array_filter( array_map( 'trim', is_array( $parts ) ? $parts : array() ) ) ) );
	}

	/**
	 * @param string $path    Route.
	 * @param string $methods HTTP methods.
	 * @param string $method  Callback method on this class.
	 */
	private function route( string $path, string $methods, string $method ): void {
		register_rest_route(
			self::NAMESPACE,
			$path,
			array(
				'methods'             => $methods,
				'callback'            => array( $this, $method ),
				'permission_callback' => array( $this, 'can_manage' ),
			)
		);
	}

	private function not_found(): WP_Error {
		return new WP_Error( 'cnwscoupons_not_found', __( 'The campaign does not exist.', 'webstyle-coupons' ), array( 'status' => 404 ) );
	}

	/**
	 * @param WP_Error $error Validation error.
	 */
	private function error( WP_Error $error ): WP_Error {
		$error->add_data( array( 'status' => 400 ) );

		return $error;
	}
}