<?php
/**
 * REST route for the AI Advisor.
 *
 * @package TurtleReport
 */

namespace TurtleReport\Rest;

use TurtleReport\Access\Capabilities;
use TurtleReport\Advisor\Advisor;

defined( 'ABSPATH' ) || exit;

/**
 * AI Advisor routes: GET /turtlereport/v1/ai/models and POST /turtlereport/v1/ai/ask.
 *
 * Only for people who manage TurtleReport, and only while the AI Advisor is
 * switched on with a key. The data sent to the provider is limited to the
 * clients the person may see; the key never leaves the server.
 */
final class AdvisorController {

	/**
	 * Advisor.
	 *
	 * @var Advisor
	 */
	private $advisor;

	/**
	 * Constructor.
	 *
	 * @param Advisor $advisor Advisor.
	 */
	public function __construct( Advisor $advisor ) {
		$this->advisor = $advisor;
	}

	/**
	 * Registers routes.
	 *
	 * @return void
	 */
	public function register_routes() {
		register_rest_route(
			ReportController::NAMESPACE_V1,
			'/ai/models',
			array(
				'methods'             => \WP_REST_Server::READABLE,
				'callback'            => array( $this, 'models' ),
				'permission_callback' => static function () {
					return current_user_can( Capabilities::MANAGE );
				},
				'args'                => array(
					'provider' => array(
						'type'     => 'string',
						'required' => true,
						'pattern'  => '^[a-z0-9_]{2,20}$',
					),
					'fresh'    => array(
						'type'    => 'boolean',
						'default' => false,
					),
				),
			)
		);
		register_rest_route(
			ReportController::NAMESPACE_V1,
			'/ai/ask',
			array(
				'methods'             => \WP_REST_Server::CREATABLE,
				'callback'            => array( $this, 'ask' ),
				'permission_callback' => array( $this, 'can_ask' ),
				'args'                => array(
					'scope'    => array(
						'type'              => 'string',
						'required'          => true,
						'validate_callback' => static function ( $v ) {
							return is_string( $v ) && ( 'all' === $v || preg_match( '/^[a-z0-9]{2,20}$/', $v ) );
						},
					),
					'question' => array(
						'type'      => 'string',
						'required'  => true,
						'minLength' => 1,
						'maxLength' => Advisor::MAX_QUESTION,
					),
					'mode'     => array(
						'type'    => 'string',
						'enum'    => array( 'answer', 'slack' ),
						'default' => 'answer',
					),
					'issue'    => array(
						'type'    => 'string',
						'default' => '',
						'pattern' => '^([a-f0-9]{10})?$',
					),
					'history'  => array(
						'type'     => 'array',
						'default'  => array(),
						'maxItems' => Advisor::HISTORY,
						'items'    => array(
							'type'                 => 'object',
							'required'             => array( 'role', 'text' ),
							'additionalProperties' => false,
							'properties'           => array(
								'role' => array(
									'type' => 'string',
									'enum' => array( 'user', 'assistant' ),
								),
								'text' => array(
									'type'      => 'string',
									'maxLength' => Advisor::MAX_ANSWER_TURN,
								),
							),
						),
					),
					'period'   => array(
						'type'                 => 'object',
						'default'              => array(),
						'additionalProperties' => false,
						'properties'           => array_fill_keys(
							array( 's', 'e', 'ps', 'pe' ),
							array(
								'type'    => 'string',
								'pattern' => '^\d{4}-\d{2}-\d{2}$',
							)
						),
					),
				),
			)
		);
	}

	/**
	 * GET /ai/models: the models a provider's saved key can use (Settings → AI Advisor).
	 *
	 * @param \WP_REST_Request $request Request.
	 * @return \WP_REST_Response
	 */
	public function models( \WP_REST_Request $request ) {
		return rest_ensure_response( $this->advisor->live_models( (string) $request['provider'], (bool) $request['fresh'] ) );
	}

	/**
	 * Permission: manages TurtleReport and the Advisor is ready.
	 *
	 * @return bool|\WP_Error
	 */
	public function can_ask() {
		if ( ! current_user_can( Capabilities::MANAGE ) ) {
			return false;
		}
		if ( ! $this->advisor->ready() ) {
			return new \WP_Error( 'turtlereport_ai_off', __( 'The AI Advisor isn\'t switched on. An administrator can set it up in Settings → AI Advisor.', 'turtlereport' ), array( 'status' => 403 ) );
		}
		return true;
	}

	/**
	 * Answers a question.
	 *
	 * @param \WP_REST_Request $request Request.
	 * @return \WP_REST_Response|\WP_Error
	 */
	public function ask( \WP_REST_Request $request ) {
		$history = array();
		foreach ( array_slice( (array) $request['history'], -Advisor::HISTORY ) as $turn ) {
			if ( is_array( $turn ) && isset( $turn['text'] ) && is_string( $turn['text'] ) ) {
				$history[] = array(
					'role' => isset( $turn['role'] ) && 'assistant' === $turn['role'] ? 'assistant' : 'user',
					'text' => (string) $turn['text'],
				);
			}
		}
		$answer = $this->advisor->ask(
			get_current_user_id(),
			(string) $request['scope'],
			(string) $request['question'],
			$history,
			array(
				'mode'   => (string) $request['mode'],
				'issue'  => (string) $request['issue'],
				'period' => (array) $request['period'],
			)
		);
		return is_wp_error( $answer ) ? $answer : rest_ensure_response( $answer );
	}
}