<?php

namespace Picea\ControlStructure;

class FunctionToken implements ControlStructure {

    public array $token = [ "function", "endfunction", "return" ];

    public function parse(\Picea\Compiler\Context &$context, ?string $arguments, string $token, array $options = []) : string {
        switch($token) {
            case "function":
                $context->functions++;

                return $this->printFunction($context, $arguments);

            case "return":
                if ( empty($context->functions) ) {
                    throw new \RuntimeException("A function return tag {% return %} was found without an opening {% function ... %} tag");
                }

                return $this->printReturn($context, $arguments);

            case "endfunction":
                if ( empty($context->functions) ) {
                    throw new \RuntimeException("A function closing tag {% endfunction %} was found without an opening {% function ... %} tag");
                }

                $context->functions--;

                return $this->printEndFunction($context);
        }
    }

    protected function printFunction($context, ?string $arguments) : string
    {
        $name = trim(explode('(', $arguments, 2)[0]);

        return "<?php if (! function_exists(__NAMESPACE__ . '\\$name')) { function $arguments { ?>";
    }

    protected function printReturn($context, ?string $arguments) : string
    {
        return "<?php return $arguments; ?>";
    }

    protected function printEndFunction($context) : string
    {
        return "<?php } } ?>";
    }
}