<?php declare(strict_types=1);

namespace Picea;

use Picea\Event\Compiler\CompileTokenExtension;
use Picea\Event\Compiler\CompileTokenExtensionEvent;
use Picea\Event\Compiler\CompileTokenTagEvent;
use Picea\Exception\RegisterExtensionToken;
use Picea\Extension\FunctionExtension;
use Picea\Language\LanguageRegistration;

class Compiler
{
    use EventTrait;

    protected string $sourceCode = "";

    protected array $syntaxObjectList = [];

    protected array $tagList = [];

    protected string $tagTokenOpen = "\{%";

    protected string $tagTokenClose = "%\}";

    public array $extensionList = [];

    public function __construct(
        public LanguageRegistration $languageRegistration
    )
    {
        $this->languageRegistration->registerAll($this);
    }

    public function compile(Compiler\Context $context) : string
    {
        $context->compiler = $this;

        /**
         * Syntaxes such as {{ echo }} & {{= echo raw }} && {# comment #}
         */
        foreach($this->syntaxObjectList as $syntax) {
            $syntax->parse($context, $this->sourceCode);
        }

        /**
         * Control structures & functions {% functionName arguments %}
         */
        $replace = "#({$this->tagTokenOpen})(.*?)({$this->tagTokenClose})#s";

        $this->sourceCode = preg_replace_callback($replace, function ($matches) use (&$context) {
            $matches[2] = trim($matches[2]);

            list($token, $arguments) = array_pad(array_filter(explode(' ', $matches[2], 2), 'strlen'), 2, null);

            $token = strtolower(trim($token));
            $tokenName = $context->tokenName($token);
            $tokenOptions = $context->tokenOptions($token);

            if ( $this->tagList[$tokenName] ?? false ) {
                $this->eventExecute(CompileTokenTagEvent::class, $context, $arguments, $tokenName, $tokenOptions);

                return $this->tagList[$tokenName]->parse($context, $arguments, $tokenName, $tokenOptions);
            }
            elseif ( $this->extensionList[$tokenName] ?? false ) {
                $this->eventExecute(CompileTokenExtensionEvent::class, $context, $arguments, $tokenName, $tokenOptions);

                return $this->extensionList[$tokenName]->parse($context, $arguments, $tokenName, $tokenOptions);
            }
            else {
                throw new \LogicException("Impossible to find token `$tokenName` declared in `{$matches[2]}`. Perhapse you forgot to add a custom token to Picea's engine ?");
            }

        }, $this->sourceCode);

        return $this->sourceCode;
    }

    public function loadSourceCode($html) : self
    {
        $this->sourceCode = $html;
        return $this;
    }

    public function registerCaching(CachingStrategy $cachingStrategy) : self
    {
    	return $this;
    }

    public function registerSyntax(Syntax\Syntax $syntaxObject) : self
    {
        $this->syntaxObjectList[get_class($syntaxObject)] = $syntaxObject;

        return $this;
    }

    public function registerControlStructure(ControlStructure\ControlStructure $controlStructureObject) : self
    {
        foreach($controlStructureObject->tokens ?? (array) ( $controlStructureObject->token ?? [] ) as $token) {
            if ( strpos($token, '.') !== false ) {
                throw new RegisterExtensionToken(sprintf("Could not register token '%s' from control structure '%s' in this version. Options are now delt by extensions themselve instead.", $token, $controlStructureObject::class));
            }

            $this->tagList[strtolower($token)] = $controlStructureObject;
        }

        return $this;
    }

    public function registerExtension(Extension\Extension $extension) : self
    {
        $tokens = $extension->tokens ?? (array) ( $extension->token ?? [] );

        foreach($tokens as $token) {
            if ( strpos($token, '.') !== false ) {
                throw new RegisterExtensionToken(sprintf("Could not register token '%s' from extension '%s' in this version. Options are now delt by extensions themselve instead.", $token, $extension::class));
            }

            $this->extensionList[strtolower($token)] = $extension;
        }

        if (! $tokens ) {
            $this->extensionList[] = $extension;
        }

        return $this;
    }

    public function registerExtensionsFunctions(Compiler\Context $context) : void
    {
        foreach($this->extensionList as $ext) {
            if ($ext instanceof FunctionExtension) {
                foreach ($ext->exportFunctions() as $name => $value) {
                    $callable = is_string($value) ? fn(...$args) => call_user_func_array([ $ext, $value ], $args) : null;

                    $context->pushFunction(is_numeric($name) ? $value : $name, $callable ?? $value);
                }
            }
        }

    }

    public function __toString() : string
    {
        return "???";
    }

    public function getExtensionFromToken(string $name) : Extension\Extension
    {
        $tokenName = explode('.', $name)[0];

        if ( ! isset($this->extensionList[$tokenName]) ) {
            throw new \InvalidArgumentException(<<<MSG
                Requested extension from token `$tokenName` could not be found from loaded Picea compiler's extension.
            MSG);
        }

        return $this->extensionList[$tokenName];
    }

    public function exportFunctions() : void
    {
        static $caching = [];
        eval( $this->context->renderFunctions() );
    }

}