<?php
/**
 * @package    Grav.Common
 *
 * @copyright  Copyright (C) 2015 - 2018 Trilby Media, LLC. All rights reserved.
 * @license    MIT License; see LICENSE file for details.
 */

namespace Grav\Common;

use DebugBar\DataCollector\ConfigCollector;
use DebugBar\DataCollector\MessagesCollector;
use DebugBar\JavascriptRenderer;
use DebugBar\StandardDebugBar;
use Grav\Common\Config\Config;

class Debugger
{
    /** @var Grav $grav */
    protected $grav;

    /** @var Config $config */
    protected $config;

    /** @var JavascriptRenderer $renderer */
    protected $renderer;

    /** @var StandardDebugBar $debugbar */
    protected $debugbar;

    protected $enabled;

    protected $timers = [];

    /** @var string[] $deprecations */
    protected $deprecations = [];

    protected $errorHandler;

    /**
     * Debugger constructor.
     */
    public function __construct()
    {
        // Enable debugger until $this->init() gets called.
        $this->enabled = true;

        $this->debugbar = new StandardDebugBar();
        $this->debugbar['time']->addMeasure('Loading', $this->debugbar['time']->getRequestStartTime(), microtime(true));

        // Set deprecation collector.
        $this->setErrorHandler();
    }

    /**
     * Initialize the debugger
     *
     * @return $this
     * @throws \DebugBar\DebugBarException
     */
    public function init()
    {
        $this->grav = Grav::instance();
        $this->config = $this->grav['config'];

        // Enable/disable debugger based on configuration.
        $this->enabled = $this->config->get('system.debugger.enabled');

        if ($this->enabled()) {

            $plugins_config = (array)$this->config->get('plugins');

            ksort($plugins_config);


            $this->debugbar->addCollector(new ConfigCollector((array)$this->config->get('system'), 'Config'));
            $this->debugbar->addCollector(new ConfigCollector($plugins_config, 'Plugins'));
            $this->addMessage('Grav v' . GRAV_VERSION);
        }

        return $this;
    }

    /**
     * Set/get the enabled state of the debugger
     *
     * @param bool $state If null, the method returns the enabled value. If set, the method sets the enabled state
     *
     * @return null
     */
    public function enabled($state = null)
    {
        if ($state !== null) {
            $this->enabled = $state;
        }

        return $this->enabled;
    }

    /**
     * Add the debugger assets to the Grav Assets
     *
     * @return $this
     */
    public function addAssets()
    {
        if ($this->enabled()) {

            // Only add assets if Page is HTML
            $page = $this->grav['page'];
            if ($page->templateFormat() !== 'html') {
                return $this;
            }

            /** @var Assets $assets */
            $assets = $this->grav['assets'];

            // Add jquery library
            $assets->add('jquery', 101);

            $this->renderer = $this->debugbar->getJavascriptRenderer();
            $this->renderer->setIncludeVendors(false);

            // Get the required CSS files
            list($css_files, $js_files) = $this->renderer->getAssets(null, JavascriptRenderer::RELATIVE_URL);
            foreach ((array)$css_files as $css) {
                $assets->addCss($css);
            }

            $assets->addCss('/system/assets/debugger.css');

            foreach ((array)$js_files as $js) {
                $assets->addJs($js);
            }
        }

        return $this;
    }

    public function getCaller($limit = 2)
    {
        $trace = debug_backtrace(false, $limit);

        return array_pop($trace);
    }

    /**
     * Adds a data collector
     *
     * @param $collector
     *
     * @return $this
     * @throws \DebugBar\DebugBarException
     */
    public function addCollector($collector)
    {
        $this->debugbar->addCollector($collector);

        return $this;
    }

    /**
     * Returns a data collector
     *
     * @param $collector
     *
     * @return \DebugBar\DataCollector\DataCollectorInterface
     * @throws \DebugBar\DebugBarException
     */
    public function getCollector($collector)
    {
        return $this->debugbar->getCollector($collector);
    }

    /**
     * Displays the debug bar
     *
     * @return $this
     */
    public function render()
    {
        if ($this->enabled()) {
            // Only add assets if Page is HTML
            $page = $this->grav['page'];
            if (!$this->renderer || $page->templateFormat() !== 'html') {
                return $this;
            }

            $this->addDeprecations();

            echo $this->renderer->render();
        }

        return $this;
    }

    /**
     * Sends the data through the HTTP headers
     *
     * @return $this
     */
    public function sendDataInHeaders()
    {
        if ($this->enabled()) {
            $this->addDeprecations();
            $this->debugbar->sendDataInHeaders();
        }

        return $this;
    }

    /**
     * Returns collected debugger data.
     *
     * @return array
     */
    public function getData()
    {
        if (!$this->enabled()) {
            return null;
        }

        $this->addDeprecations();
        $this->timers = [];

        return $this->debugbar->getData();
    }

    /**
     * Start a timer with an associated name and description
     *
     * @param             $name
     * @param string|null $description
     *
     * @return $this
     */
    public function startTimer($name, $description = null)
    {
        if ($name[0] === '_' || $this->enabled()) {
            $this->debugbar['time']->startMeasure($name, $description);
            $this->timers[] = $name;
        }

        return $this;
    }

    /**
     * Stop the named timer
     *
     * @param string $name
     *
     * @return $this
     */
    public function stopTimer($name)
    {
        if (in_array($name, $this->timers, true) && ($name[0] === '_' || $this->enabled())) {
            $this->debugbar['time']->stopMeasure($name);
        }

        return $this;
    }

    /**
     * Dump variables into the Messages tab of the Debug Bar
     *
     * @param        $message
     * @param string $label
     * @param bool   $isString
     *
     * @return $this
     */
    public function addMessage($message, $label = 'info', $isString = true)
    {
        if ($this->enabled()) {
            $this->debugbar['messages']->addMessage($message, $label, $isString);
        }

        return $this;
    }

    /**
     * Dump exception into the Messages tab of the Debug Bar
     *
     * @param \Exception $e
     * @return Debugger
     */
    public function addException(\Exception $e)
    {
        if ($this->enabled()) {
            $this->debugbar['exceptions']->addException($e);
        }

        return $this;
    }

    public function setErrorHandler()
    {
        $this->errorHandler = set_error_handler(
            [$this, 'deprecatedErrorHandler']
        );
    }

    /**
     * @param int $errno
     * @param string $errstr
     * @param string $errfile
     * @param int $errline
     * @return bool
     */
    public function deprecatedErrorHandler($errno, $errstr, $errfile, $errline)
    {
        if ($errno !== E_USER_DEPRECATED) {
            if ($this->errorHandler) {
                return \call_user_func($this->errorHandler, $errno, $errstr, $errfile, $errline);
            }

            return true;
        }

        if (!$this->enabled()) {
            return true;
        }

        $backtrace = debug_backtrace(false);

        // Skip current call.
        array_shift($backtrace);

        // Skip vendor libraries and the method where error was triggered.
        while ($current = array_shift($backtrace)) {
            if (isset($current['file']) && strpos($current['file'], 'vendor') !== false) {
                continue;
            }
            if (isset($current['function']) && ($current['function'] === 'user_error' || $current['function'] === 'trigger_error')) {
                $current = array_shift($backtrace);
            }

            break;
        }

        // Add back last call.
        array_unshift($backtrace, $current);

        // Filter arguments.
        foreach ($backtrace as &$current) {
            if (isset($current['args'])) {
                $args = [];
                foreach ($current['args'] as $arg) {
                    if (\is_string($arg)) {
                        $args[] = "'" . $arg . "'";
                    } elseif (\is_bool($arg)) {
                        $args[] = $arg ? 'true' : 'false';
                    } elseif (\is_scalar($arg)) {
                        $args[] = $arg;
                    } elseif (\is_object($arg)) {
                        $args[] = get_class($arg) . ' $object';
                    } elseif (\is_array($arg)) {
                        $args[] = '$array';
                    } else {
                        $args[] = '$object';
                    }
                }
                $current['args'] = $args;
            }
        }
        unset($current);

        $this->deprecations[] = [
            'message' => $errstr,
            'file' => $errfile,
            'line' => $errline,
            'trace' => $backtrace,
        ];

        // Do not pass forward.
        return true;
    }

    protected function addDeprecations()
    {
        if (!$this->deprecations) {
            return;
        }

        $collector = new MessagesCollector('deprecated');
        $this->addCollector($collector);
        $collector->addMessage('Your site is using following deprecated features:');

        /** @var array $deprecated */
        foreach ($this->deprecations as $deprecated) {
            list($message, $scope) = $this->getDepracatedMessage($deprecated);

            $collector->addMessage($message, $scope);
        }
    }

    protected function getDepracatedMessage($deprecated)
    {
        $scope = 'unknown';
        if (stripos($deprecated['message'], 'grav') !== false) {
            $scope = 'grav';
        } elseif (!isset($deprecated['file'])) {
            $scope = 'unknown';
        } elseif (stripos($deprecated['file'], 'twig') !== false) {
            $scope = 'twig';
        } elseif (stripos($deprecated['file'], 'yaml') !== false) {
            $scope = 'yaml';
        } elseif (stripos($deprecated['file'], 'vendor') !== false) {
            $scope = 'vendor';
        }

        $trace = [];
        foreach ($deprecated['trace'] as $current) {
            $class = isset($current['class']) ? $current['class'] : '';
            $type = isset($current['type']) ? $current['type'] : '';
            $function = $this->getFunction($current);
            if (isset($current['file'])) {
                $current['file'] = str_replace(GRAV_ROOT . '/', '', $current['file']);
            }

            unset($current['class'], $current['type'], $current['function'], $current['args']);

            $trace[] = ['call' => $class . $type . $function] + $current;
        }

        return [
            [
                'message' => $deprecated['message'],
                'trace' => $trace
            ],
            $scope
        ];
    }

    protected function getFunction($trace)
    {
        if (!isset($trace['function'])) {
            return '';
        }

        return $trace['function'] . '(' . implode(', ', $trace['args']) . ')';
    }
}