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<?php

/**
 * MvcCore
 *
 * This source file is subject to the BSD 3 License
 * For the full copyright and license information, please view
 * the LICENSE.md file that are distributed with this source code.
 *
 * @copyright   Copyright (c) 2016 Tom Flidr (https://github.com/mvccore)
 * @license  https://mvccore.github.io/docs/mvccore/5.0.0/LICENCE.md
 */

namespace MvcCore\View;

trait ViewHelpers {

    /**
     * @inheritDocs
     * @return string
     */
    public static function GetHelpersDir () {
        return static::$helpersDir;
    }

    /**
     * @inheritDocs
     * @param string $helpersDir
     * @return string
     */
    public static function SetHelpersDir ($helpersDir = 'Helpers') {
        return static::$helpersDir = $helpersDir;
    }

    /**
     * @inheritDocs
     * @param string $helperNamespaces,... View helper classes namespace(s).
     * @return void
     */
    public static function AddHelpersNamespaces ($helperNamespaces) {
        if (!static::$helpersNamespaces) self::initHelpersNamespaces();
        $args = func_get_args();
        if (count($args) === 1 && is_array($args[0])) $args = $args[0];
        foreach ($args as $arg)
            static::$helpersNamespaces[] = '\\' . trim($arg, '\\') . '\\';
    }

    /**
     * @inheritDocs
     * @param string $helperNamespaces,... View helper classes namespace(s).
     * @return void
     */
    public static function SetHelpersNamespaces ($helperNamespaces) {
        static::$helpersNamespaces = [];
        $args = func_get_args();
        if (count($args) === 1 && is_array($args[0])) $args = $args[0];
        foreach ($args as $arg)
            static::$helpersNamespaces[] = '\\' . trim($arg, '\\') . '\\';
    }

    /**
     * @inheritDocs
     * @param string $method View helper method name in pascal case.
     * @param mixed $arguments View helper method arguments.
     * @throws \InvalidArgumentException If view doesn't exist in configured namespaces.
     * @return string|mixed View helper string result or any other view helper result type or view helper instance, always as `\MvcCore\Ext\Views\Helpers\AbstractHelper|\MvcCore\Ext\Views\Helpers\IHelper` instance.
     */
    public function __call ($method, $arguments) {
        /** @var $this \MvcCore\View */
        $result = '';
        $methodCamelCase = lcfirst($method);
        $instance = & $this->GetHelper($methodCamelCase, TRUE);
        $isObject = is_object($instance);
        if ($instance instanceof \Closure || ($isObject && method_exists($instance, '__invoke'))) {
            $result = call_user_func_array($instance, $arguments);
        } else if ($isObject && method_exists($instance, $method)) {
            $result = call_user_func_array([$instance, $method], $arguments);
        } else {
            throw new \InvalidArgumentException(
                "[".get_class()."] View class instance has no method '{$method}', no view helper found."
            );
        }
        $this->__protected['helpers'][$methodCamelCase] = & $instance;
        return $result;
    }

    /**
     * Try to get view helper.
     * If view helper doesn't exist in global helpers store - create new helper instance.
     * If helper already exists in global helpers store - do not create it again - use instance from the store.
     * Example: `echo $this->GetHelper('facebook')->RenderSomeSpecialWidgetMethod();`
     * @param string $helperNameCamelCase View helper method name in camel case.
     * @param bool $asClosure Get View helper prepared as closure function, `FALSE` by default.
     * @throws \InvalidArgumentException If view doesn't exist in configured namespaces.
     * @return mixed View helper instance, always as `\MvcCore\Ext\Views\Helpers\AbstractHelper|\MvcCore\Ext\Views\Helpers\IHelper` instance.
     */
    public function & GetHelper ($helperNameCamelCase, $asClosure = FALSE) {
        /** @var $this \MvcCore\View */
        $setUpView = FALSE;
        $needsClosureFn = FALSE;
        $instance = NULL;
        $helpers = & $this->__protected['helpers'];
        $helperNamePascalCase = ucfirst($helperNameCamelCase);
        if (isset($helpers[$helperNameCamelCase])) {
            $instance = & $helpers[$helperNameCamelCase];
        } else if (isset(self::$_globalHelpers[$helperNamePascalCase])) {
            $globalHelpersRecord = & self::$_globalHelpers[$helperNamePascalCase];
            $instance = & $globalHelpersRecord[0];
            //$result = & $instance;
            $setUpView = $globalHelpersRecord[1];
            $needsClosureFn = $globalHelpersRecord[2];
        } else {
            $helperFound = FALSE;
            $toolClass = self::$_toolClass ?: self::$_toolClass = \MvcCore\Application::GetInstance()->GetToolClass();
            $helpersInterface = self::HELPERS_INTERFACE_CLASS_NAME;
            if (!static::$helpersNamespaces)
                self::initHelpersNamespaces();
            foreach (static::$helpersNamespaces as $helperClassBase) {
                $className = $helperClassBase . $helperNamePascalCase . 'Helper';
                if (!class_exists($className))
                    continue;
                $helperFound = TRUE;
                if ($toolClass::CheckClassInterface($className, $helpersInterface, TRUE, FALSE)) {
                    $setUpView = TRUE;
                    $instance = $className::GetInstance();
                } else {
                    $instance = new $className();
                }
                $needsClosureFn = (
                    !($instance instanceof \Closure) &&
                    !method_exists($className, '__invoke')
                );
                self::$_globalHelpers[$helperNamePascalCase] = [& $instance, $setUpView, $needsClosureFn];
                break;
            }
            if (!$helperFound)
                throw new \InvalidArgumentException(
                    "[".get_class()."] View helper method '{$helperNamePascalCase}' is not"
                    ." possible to handle by any configured view helper (View"
                    ." helper namespaces: '".implode("', '", static::$helpersNamespaces)."')."
                );
        }
        if ($setUpView)
            $instance->SetView($this);
        if ($needsClosureFn) {
            $result = function () use (& $instance, $helperNamePascalCase) {
                return call_user_func_array([$instance, $helperNamePascalCase], func_get_args());
            };
            $helpers[$helperNameCamelCase] = & $result;
        } else {
            $helpers[$helperNameCamelCase] = & $instance;
            $result = & $instance;
        }
        if ($asClosure) {
            return $result;
        } else {
            return $instance;
        }
    }

    /**
     * Set view helper for current template or for all templates globally by default.
     * If view helper already exist in global helpers store - it's overwritten.
     * @param string $helperNameCamelCase View helper method name in camel case.
     * @param mixed $instance View helper instance, always as `\MvcCore\Ext\Views\Helpers\AbstractHelper|\MvcCore\Ext\Views\Helpers\IHelper` instance or `\Closure`.
     * @param bool $forAllTemplates register this helper instance for all rendered views in the future.
     * @return \MvcCore\View
     */
    public function SetHelper ($helperNameCamelCase, $instance, $forAllTemplates = TRUE) {
        /** @var $this \MvcCore\View */
        $implementsIHelper = FALSE;
        if (self::$_toolClass === NULL)
            self::$_toolClass = \MvcCore\Application::GetInstance()->GetToolClass();
        $toolClass = self::$_toolClass;
        $helpersInterface = self::HELPERS_INTERFACE_CLASS_NAME;
        $className = get_class($instance);
        $implementsIHelper = $toolClass::CheckClassInterface($className, $helpersInterface, FALSE, FALSE);
        $helperNamePascalCase = ucfirst($helperNameCamelCase);
        $needsClosureFn = (
            !($instance instanceof \Closure) &&
            !method_exists($className, '__invoke')
        );
        if ($forAllTemplates)
            self::$_globalHelpers[ucfirst($helperNameCamelCase)] = [
                & $instance, $implementsIHelper, $needsClosureFn
            ];
        $helpers = & $this->__protected['helpers'];
        if ($needsClosureFn) {
            $helpers[$helperNameCamelCase] = function () use (& $instance, $helperNamePascalCase) {
                return call_user_func_array([$instance, $helperNamePascalCase], func_get_args());
            };
        } else {
            $helpers[$helperNameCamelCase] = & $instance;
        }
        return $this;
    }
}