<?php

/*
 * This file is part of Psy Shell.
 *
 * (c) 2012-2015 Justin Hileman
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Psy\Command;

use Psy\Output\ShellOutput;
use Symfony\Component\Console\Formatter\OutputFormatter;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;

/**
 * Show the current stack trace.
 */
class TraceCommand extends Command
{
    /**
     * {@inheritdoc}
     */
    protected function configure()
    {
        $this
            ->setName('trace')
            ->setDefinition(array(
                new InputOption('include-psy', 'p', InputOption::VALUE_NONE,     'Include Psy in the call stack.'),
                new InputOption('num',         'n', InputOption::VALUE_REQUIRED, 'Only include NUM lines.'),
            ))
            ->setDescription('Show the current call stack.')
            ->setHelp(
                <<<HELP
Show the current call stack.

Optionally, include PsySH in the call stack by passing the <info>--include-psy</info> option.

e.g.
<return>> trace -n10</return>
<return>> trace --include-psy</return>
HELP
            );
    }

    /**
     * {@inheritdoc}
     */
    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $trace = $this->getBacktrace(new \Exception(), $input->getOption('num'), $input->getOption('include-psy'));
        $output->page($trace, ShellOutput::NUMBER_LINES);
    }

    /**
     * Get a backtrace for an exception.
     *
     * Optionally limit the number of rows to include with $count, and exclude
     * Psy from the trace.
     *
     * @param \Exception $e          The exception with a backtrace.
     * @param int        $count      (default: PHP_INT_MAX)
     * @param bool       $includePsy (default: true)
     *
     * @return array Formatted stacktrace lines.
     */
    protected function getBacktrace(\Exception $e, $count = null, $includePsy = true)
    {
        if ($cwd = getcwd()) {
            $cwd = rtrim($cwd, DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR;
        }

        if ($count === null) {
            $count = PHP_INT_MAX;
        }

        $lines = array();

        $trace = $e->getTrace();
        array_unshift($trace, array(
            'function' => '',
            'file'     => $e->getFile() !== null ? $e->getFile() : 'n/a',
            'line'     => $e->getLine() !== null ? $e->getLine() : 'n/a',
            'args'     => array(),
        ));

        if (!$includePsy) {
            for ($i = count($trace) - 1; $i >= 0; $i--) {
                $thing = isset($trace[$i]['class']) ? $trace[$i]['class'] : $trace[$i]['function'];
                if (preg_match('/\\\\?Psy\\\\/', $thing)) {
                    $trace = array_slice($trace, $i + 1);
                    break;
                }
            }
        }

        for ($i = 0, $count = min($count, count($trace)); $i < $count; $i++) {
            $class    = isset($trace[$i]['class']) ? $trace[$i]['class'] : '';
            $type     = isset($trace[$i]['type']) ? $trace[$i]['type'] : '';
            $function = $trace[$i]['function'];
            $file     = isset($trace[$i]['file']) ? $this->replaceCwd($cwd, $trace[$i]['file']) : 'n/a';
            $line     = isset($trace[$i]['line']) ? $trace[$i]['line'] : 'n/a';

            $lines[] = sprintf(
                ' <class>%s</class>%s%s() at <info>%s:%s</info>',
                OutputFormatter::escape($class),
                OutputFormatter::escape($type),
                OutputFormatter::escape($function),
                OutputFormatter::escape($file),
                OutputFormatter::escape($line)
            );
        }

        return $lines;
    }

    /**
     * Replace the given directory from the start of a filepath.
     *
     * @param string $cwd
     * @param string $file
     *
     * @return string
     */
    private function replaceCwd($cwd, $file)
    {
        if ($cwd === false) {
            return $file;
        } else {
            return preg_replace('/^' . preg_quote($cwd, '/') . '/', '', $file);
        }
    }
}
