<?php

namespace Laravel\Ai\Concerns;

use Laravel\Ai\Contracts\ConversationStore;

trait RemembersConversations
{
    protected ?string $conversationId = null;

    protected ?object $conversationUser = null;

    /**
     * Start a new conversation for the given user.
     */
    public function forUser($user): static
    {
        $this->conversationUser = $user;

        return $this;
    }

    /**
     * Continue an existing conversation as the given user.
     */
    public function continue(string $conversationId, object $as): static
    {
        $this->conversationId = $conversationId;
        $this->conversationUser = $as;

        return $this;
    }

    /**
     * Continue an existing conversation as the given user.
     */
    public function continueLastConversation(object $as): static
    {
        $this->conversationUser = $as;

        $this->conversationId = resolve(ConversationStore::class)
            ->latestConversationId($as->id);

        return $this;
    }

    /**
     * Get the list of messages comprising the conversation so far.
     */
    public function messages(): iterable
    {
        if (! $this->conversationId) {
            return [];
        }

        return resolve(ConversationStore::class)
            ->getLatestConversationMessages(
                $this->conversationId,
                $this->maxConversationMessages()
            )->all();
    }

    /**
     * Get the maximum number of conversation messages to include in context.
     */
    protected function maxConversationMessages(): int
    {
        return 100;
    }

    /**
     * Get the UUID for the current conversation, if applicable.
     */
    public function currentConversation(): ?string
    {
        return $this->conversationId;
    }

    /**
     * Determine if the conversation has a participant and is thus being remembered.
     */
    public function hasConversationParticipant(): bool
    {
        return $this->conversationUser !== null;
    }

    /**
     * Get the user having the current conversation.
     */
    public function conversationParticipant(): ?object
    {
        return $this->conversationUser;
    }
}
