<?php
/**
 * Tool step that ends the turn after quick replies
 *
 * @package Aisentic\Agent
 */

declare(strict_types=1);

namespace Aisentic\Agent;

use Generator;
use Aisentic\PublicAgent\Suggest_Replies_Tool;
use NeuronAI\Agent\AgentState;
use NeuronAI\Agent\Events\AIInferenceEvent;
use NeuronAI\Agent\Events\ToolCallEvent;
use NeuronAI\Agent\Nodes\ToolNode;
use NeuronAI\Chat\Messages\AssistantMessage;
use NeuronAI\Chat\Messages\ToolResultMessage;
use NeuronAI\Workflow\Events\StopEvent;

defined( 'ABSPATH' ) || exit;

/**
 * Runs tools like the stock ToolNode, but stops the turn when the only tool
 * was `suggest-replies` and the model already wrote its question: the chips
 * need no answer, and asking the model again made it write the whole
 * question and its options a second time.
 */
class Quick_Reply_Tool_Node extends ToolNode {

	/**
	 * Run the called tools, then go back to the model or end the turn.
	 *
	 * The declared type matches ToolNode (PHP will not widen it); as a
	 * generator this always returns a Generator, whose final value is the
	 * next event, and the workflow stops on any StopEvent.
	 *
	 * @param ToolCallEvent $event Tool call.
	 * @param AgentState    $state State.
	 * @return AIInferenceEvent|Generator
	 */
	public function __invoke( ToolCallEvent $event, AgentState $state ): AIInferenceEvent|Generator {
		// phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase -- Vendor (NeuronAI) property name.
		$this->addToChatHistory( $state, $event->toolCallMessage );

		// phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase -- Vendor (NeuronAI) property name.
		$result = yield from $this->executeTools( $event->toolCallMessage, $state );

		if ( $this->only_quick_replies_after_text( $event ) && $this->all_succeeded( $result ) ) {
			// The next model step would have added the results; it does not
			// run, and a tool call must be followed by its result.
			$this->addToChatHistory( $state, $result );
			// The non-streaming chat returns the last message in the history:
			// the question, not the empty tool result.
			// phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase -- Vendor (NeuronAI) property name.
			$this->addToChatHistory( $state, new AssistantMessage( (string) $event->toolCallMessage->getContent() ) );

			return new StopEvent();
		}

		// phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase -- Vendor (NeuronAI) property name.
		$event->inferenceEvent->setMessages( $result );

		// phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase -- Vendor (NeuronAI) property name.
		return $event->inferenceEvent;
	}

	/**
	 * Whether every tool returned ok. A refused call (e.g. one option) showed
	 * no chips, so the model must be asked again.
	 *
	 * @param ToolResultMessage $result Tool results.
	 * @return bool
	 */
	private function all_succeeded( ToolResultMessage $result ): bool {
		foreach ( $result->getTools() as $tool ) {
			if ( true !== ( json_decode( (string) $tool->getResult(), true )['ok'] ?? null ) ) {
				return false;
			}
		}

		return true;
	}

	/**
	 * Whether every tool called was `suggest-replies` after some text.
	 *
	 * Any text counts, finished or not: the model often loses the last bit of
	 * its text (the "?", a closing "**") when it switches to the tool call,
	 * so the text cannot be trusted to end in a question mark. With no text at
	 * all the question is still to be written, so the model is asked again.
	 *
	 * @param ToolCallEvent $event Tool call.
	 * @return bool
	 */
	private function only_quick_replies_after_text( ToolCallEvent $event ): bool {
		// phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase -- Vendor (NeuronAI) property name.
		$tools = $event->toolCallMessage->getTools();

		foreach ( $tools as $tool ) {
			if ( ! $tool instanceof Suggest_Replies_Tool ) {
				return false;
			}
		}

		// phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase -- Vendor (NeuronAI) property name.
		return [] !== $tools && '' !== trim( (string) $event->toolCallMessage->getContent() );
	}
}