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<?php

    namespace Deliverist\Builder\Commands;

    use Deliverist\Builder\Builder;
    use Deliverist\Builder\InvalidArgumentException;
    use Deliverist\Builder\ICommand;


    class GoogleAnalytics implements ICommand
    {
        /**
         * @param  Builder
         * @param  string
         * @param  string
         * @param  string|NULL
         */
        public function run(Builder $builder, $file = NULL, $code = NULL, $placeholder = NULL)
        {
            $builder->log("Inserting Google Analytics code '$code' into '$file'.");

            if (!is_string($file)) {
                throw new InvalidArgumentException('File must be string, ' . gettype($file) . ' given.');
            }

            if (!is_string($code)) {
                throw new InvalidArgumentException('Code must be string, ' . gettype($code) . ' given.');
            }

            $parameters = $this->prepareParameters($file, $placeholder);
            $script = array(
                '<script' . (isset($parameters['attributes']) ? (' ' . $parameters['attributes']) : '') . '>',
                'ga=function(){ga.q.push(arguments)};ga.q=[];ga.l=+new Date;',
                "ga('create'," . json_encode((string) $code) . ",'auto');ga('send','pageview');",
                '</script>',
                '<script src="https://www.google-analytics.com/analytics.js" async defer></script>',
            );

            $content = $builder->readFile($file);
            $content = strtr($content, array(
                $parameters['placeholder'] => implode('', $script),
            ));
            $builder->writeFile($file, $content);
        }


        /**
         * @param  string
         * @param  string|NULL
         * @return array
         */
        private function prepareParameters($file, $placeholder)
        {
            $parameters = array(
                'attributes' => NULL,
                'placeholder' => NULL,
            );

            $extension = strtolower(pathinfo($file, PATHINFO_EXTENSION));

            if ($extension === 'latte') {
                $parameters['placeholder'] = '{* GA *}';
                $parameters['attributes'] = 'n:syntax="off"';

            } elseif ($extension === 'html') {
                $parameters['placeholder'] = '<!-- GA -->';
            }

            if ($parameters['placeholder'] === NULL) {
                $parameters['placeholder'] = $placeholder;
            }

            if ($parameters['placeholder'] === NULL) {
                throw new InvalidArgumentException("Missing placeholder, unknow file extension '$extension'.");
            }

            return $parameters;
        }
    }