<?php
/**
 * PHPTAL templating engine
 *
 * PHP Version 5
 *
 * @category HTML
 * @package  PHPTAL
 * @author   Laurent Bedubourg <lbedubourg@motion-twin.com>
 * @author   Kornel Lesiński <kornel@aardvarkmedia.co.uk>
 * @license  http://www.gnu.org/licenses/lgpl.html GNU Lesser General Public License
 * @version  SVN: $Id$
 * @link     http://phptal.org/
 */

/**
 * Exception that is related to location within a template.
 * You can check srcFile and srcLine to find source of the error.
 *
 * @package PHPTAL
 * @subpackage Exception
 */
class PHPTAL_TemplateException extends PHPTAL_Exception
{
    public $srcFile;
    public $srcLine;
    private $is_src_accurate;

    public function __construct($msg, $srcFile='', $srcLine=0)
    {
        parent::__construct($msg);

        if ($srcFile && $srcLine) {
            $this->srcFile = $srcFile;
            $this->srcLine = $srcLine;
            $this->is_src_accurate = true;
        } else {
            $this->is_src_accurate = $this->setTemplateSource();
        }

        if ($this->is_src_accurate) {
            $this->file = $this->srcFile;
            $this->line = (int)$this->srcLine;
        }
    }

    public function __toString()
    {
        if (!$this->srcFile || $this->is_src_accurate) return parent::__toString();
        return "From {$this->srcFile} around line {$this->srcLine}\n".parent::__toString();
    }

    /**
     * Set new TAL source file/line if it isn't known already
     */
    public function hintSrcPosition($srcFile, $srcLine)
    {
        if ($srcFile && $srcLine) {
            if (!$this->is_src_accurate) {
                $this->srcFile = $srcFile;
                $this->srcLine = $srcLine;
                $this->is_src_accurate = true;
            } else if ($this->srcLine <= 1 && $this->srcFile === $srcFile) {
                $this->srcLine = $srcLine;
            }
        }

        if ($this->is_src_accurate) {
            $this->file = $this->srcFile;
            $this->line = (int)$this->srcLine;
        }
    }

    private function isTemplatePath($path)
    {
        return preg_match('/[\\\\\/]tpl_[0-9a-f]{8}_[^\\\\]+$/', $path);
    }

    private function findFileAndLine()
    {
        if ($this->isTemplatePath($this->file)) {
            return array($this->file, $this->line);
        }

        $eval_line = 0;
        $eval_path = NULL;

        // searches backtrace to find template file
        foreach($this->getTrace() as $tr) {
            if (!isset($tr['file'],$tr['line'])) continue;

            if ($this->isTemplatePath($tr['file'])) {
                return array($tr['file'], $tr['line']);
            }

            // PHPTAL.php uses eval() on first run to catch fatal errors. This makes template path invisible.
            // However, function name matches template path and eval() is visible in backtrace.
            if (false !== strpos($tr['file'], 'eval()')) {
                $eval_line = $tr['line'];
            }
            else if ($eval_line && isset($tr['function'],$tr['args'],$tr['args'][0]) &&
                $this->isTemplatePath("/".$tr['function'].".php") && $tr['args'][0] instanceof PHPTAL) {
                return array($tr['args'][0]->getCodePath(), $eval_line);
            }
        }

        return array(NULL,NULL);
    }

    /**
     * sets srcLine and srcFile to template path and source line
     * by checking error backtrace and scanning PHP code file
     *
     * @return bool true if found accurate data
     */
    private function setTemplateSource()
    {
        // not accurate, but better than null
        $this->srcFile = $this->file;
        $this->srcLine = $this->line;

        list($file,$line) = $this->findFileAndLine();

        if (NULL === $file) {
            return false;
        }

        // this is not accurate yet, hopefully will be overwritten later
        $this->srcFile = $file;
        $this->srcLine = $line;

        $lines = @file($file);
        if (!$lines) {
            return false;
        }

        $found_line=false;
        $found_file=false;

        // scan lines backwards looking for "from line" comments
        $end = min(count($lines), $line)-1;
        for($i=$end; $i >= 0; $i--) {
            if (preg_match('/tag "[^"]*" from line (\d+)/', $lines[$i], $m)) {
                $this->srcLine = intval($m[1]);
                $found_line=true;
                break;
            }
        }

        foreach(preg_grep('/Generated by PHPTAL from/',$lines) as $line) {
            if (preg_match('/Generated by PHPTAL from (.*) \(/', $line, $m)) {
                $this->srcFile = $m[1];
                $found_file=true;
                break;
            }
        }

        return $found_line && $found_file;
    }
}