<?php

class Meow_MWAI_Query_Function implements JsonSerializable {
  public string $name;
  public string $description;
  public array $parameters;
  public string $type;

  public function __construct( string $name, string $description, array $parameters = [], string $type = 'PHP' ) {
    // $name: The name of the function to be called. Must be a-z, A-Z, 0-9, or contain underscores and dashes, with a maximum length of 64.
    if ( !preg_match( '/^[a-zA-Z0-9_-]{1,64}$/', $name ) ) {
      throw new InvalidArgumentException( "Invalid function name ($name). It must be a-z, A-Z, 0-9, or contain underscores and dashes, with a maximum length of 64." );
    }

    foreach ( $parameters as $parameter ) {
      if ( !( $parameter instanceof Meow_MWAI_Query_Parameter ) ) {
        throw new InvalidArgumentException( "Invalid parameter." );
      }
    }

    $this->name = $name;
    $this->description = $description;
    $this->parameters = $parameters;
    $this->type = $type;
  }

  #[\ReturnTypeWillChange]
  public function jsonSerialize()
  {
    $json = [ 'name' => $this->name, 'description' => $this->description ];

    // OpenAI requires at least one parameter, so we'll add one if there are none.
    if ( empty( $this->parameters ) ) {
      $newParam = new Meow_MWAI_Query_Parameter( 
        'intendedActionConfidence',
        'The probability, in a range from 0 to 100, representing OpenAI’s confidence that invoking this function aligns with its intended action.',
        'integer',
        false
      );
      $this->parameters = [ $newParam ];
    }

    if ( !empty( $this->parameters ) ) {
      $params = [];
      foreach ( $this->parameters as $parameter ) {
        $params[$parameter->name] = $parameter;
      }
      $required = array_filter( $this->parameters, function ( $param ) { return $param->required; } );
      $required = array_map( function ( $param ) { return $param->name; }, $required );
      $json['parameters'] = [ 'type' => 'object', 'properties' => $params ];
      $json['required'] = $required;
    }
    return $json;
  }
}