<?php

/**
 * Uses cscover (http://github.com/hach-que/cstools) to report code coverage.
 *
 * This engine inherits from `XUnitTestEngine`, where xUnit is used to actually
 * run the unit tests and this class provides a thin layer on top to collect
 * code coverage data with a third-party tool.
 *
 * @group unitrun
 */

final class CSharpToolsTestEngine extends XUnitTestEngine {

  private $cscoverHintPath;
  private $coverEngine;
  private $cachedResults;
  private $matchRegex;
  private $excludedFiles;

  /**
   * Overridden version of `loadEnvironment` to support a different set
   * of configuration values and to pull in the cstools config for
   * code coverage.
   */
  protected function loadEnvironment(
    $config_item = 'unit.csharp.xunit.binary') {

    $working = $this->getWorkingCopy();
    $this->xunitHintPath = $working->getConfig('unit.csharp.xunit.binary');
    $this->cscoverHintPath = $working->getConfig('unit.csharp.cscover.binary');
    $this->matchRegex = $working->getConfig('unit.csharp.coverage.match');
    $this->excludedFiles = $working->getConfig('unit.csharp.coverage.excluded');

    parent::loadEnvironment($config_item);

    if ($this->getEnableCoverage() === false) {
      return;
    }

    // Determine coverage path.
    if ($this->cscoverHintPath === null) {
      throw new Exception(
        "Unable to locate cscover.  Configure it with ".
        "the `unit.csharp.coverage.binary' option in .arcconfig");
    }
    $cscover = $this->projectRoot."/".$this->cscoverHintPath;
    if (file_exists($cscover)) {
      $this->coverEngine = Filesystem::resolvePath($cscover);
    } else {
      throw new Exception(
        "Unable to locate cscover coverage runner ".
        "(have you built yet?)");
    }

  }

  /**
   * Returns whether the specified assembly should be instrumented for
   * code coverage reporting.  Checks the excluded file list and the
   * matching regex if they are configured.
   *
   * @return boolean Whether the assembly should be instrumented.
   */
  private function assemblyShouldBeInstrumented($file) {
    if ($this->excludedFiles !== null) {
      if (array_key_exists((string)$file, $this->excludedFiles)) {
        return false;
      }
    }
    if ($this->matchRegex !== null) {
      if (preg_match($this->matchRegex, $file) === 1) {
        return true;
      } else {
        return false;
      }
    }
    return true;
  }

  /**
   * Overridden version of `buildTestFuture` so that the unit test can be run
   * via `cscover`, which instruments assemblies and reports on code coverage.
   *
   * @param  string  Name of the test assembly.
   * @return array   The future, output filename and coverage filename
   *                 stored in an array.
   */
  protected function buildTestFuture($test_assembly) {
    if ($this->getEnableCoverage() === false) {
      return parent::buildTestFuture($test_assembly);
    }

    // FIXME: Can't use TempFile here as xUnit doesn't like
    // UNIX-style full paths.  It sees the leading / as the
    // start of an option flag, even when quoted.
    $xunit_temp = $test_assembly.".results.xml";
    if (file_exists($xunit_temp)) {
      unlink($xunit_temp);
    }
    $cover_temp = new TempFile();
    $cover_temp->setPreserveFile(true);
    $xunit_cmd = $this->runtimeEngine;
    $xunit_args = null;
    if ($xunit_cmd === "") {
      $xunit_cmd = $this->testEngine;
      $xunit_args = csprintf(
        "%s /xml %s /silent",
        $test_assembly.".dll",
        $xunit_temp);
    } else {
      $xunit_args = csprintf(
        "%s %s /xml %s /silent",
        $this->testEngine,
        $test_assembly.".dll",
        $xunit_temp);
    }
    $assembly_dir = $test_assembly."/bin/Debug/";
    $assemblies_to_instrument = array();
    foreach (Filesystem::listDirectory($assembly_dir) as $file) {
      if (substr($file, -4) == ".dll" || substr($file, -4) == ".exe") {
        if ($this->assemblyShouldBeInstrumented($file)) {
          $assemblies_to_instrument[] = $assembly_dir.$file;
        }
      }
    }
    $future = new ExecFuture(
      "%C -o %s -c %s -a %s -w %s %Ls",
      trim($this->runtimeEngine." ".$this->coverEngine),
      $cover_temp,
      $xunit_cmd,
      $xunit_args,
      $assembly_dir,
      $assemblies_to_instrument);
    $future->setCWD(Filesystem::resolvePath($this->projectRoot));
    return array(
      $future,
      $this->projectRoot."/".$assembly_dir.$xunit_temp,
      $cover_temp);
  }

  /**
   * Returns coverage results for the unit tests.
   *
   * @param  string  The name of the coverage file if one was provided by
   *                 `buildTestFuture`.
   * @return array   Code coverage results, or null.
   */
  protected function parseCoverageResult($cover_file) {
    if ($this->getEnableCoverage() === false) {
      return parent::parseCoverageResult($cover_file);
    }
    return $this->readCoverage($cover_file);
  }

  /**
   * Retrieves the cached results for a coverage result file.  The coverage
   * result file is XML and can be large depending on what has been instrumented
   * so we cache it in case it's requested again.
   *
   * @param  string  The name of the coverage file.
   * @return array   Code coverage results, or null if not cached.
   */
  private function getCachedResultsIfPossible($cover_file) {
    if ($this->cachedResults == null) {
      $this->cachedResults = array();
    }
    if (array_key_exists((string)$cover_file, $this->cachedResults)) {
      return $this->cachedResults[(string)$cover_file];
    }
    return null;
  }

  /**
   * Stores the code coverage results in the cache.
   *
   * @param  string  The name of the coverage file.
   * @param  array   The results to cache.
   */
  private function addCachedResults($cover_file, array $results) {
    if ($this->cachedResults == null) {
      $this->cachedResults = array();
    }
    $this->cachedResults[(string)$cover_file] = $results;
  }

  /**
   * Processes a set of XML tags as code coverage results.  We parse
   * the `instrumented` and `executed` tags with this method so that
   * we can access the data multiple times without a performance hit.
   *
   * @param  array  The array of XML tags to parse.
   * @return array  A PHP array containing the data.
   */
  private function processTags($tags) {
    $results = array();
    foreach ($tags as $tag) {
      $results[] = array(
        "file" => $tag->getAttribute("file"),
        "start" => $tag->getAttribute("start"),
        "end" => $tag->getAttribute("end"));
    }
    return $results;
  }

  /**
   * Reads the code coverage results from the cscover results file.
   *
   * @param  string  The path to the code coverage file.
   * @return array   The code coverage results.
   */
  public function readCoverage($cover_file) {
    $cached = $this->getCachedResultsIfPossible($cover_file);
    if ($cached !== null) {
      return $cached;
    }

    $coverage_dom = new DOMDocument();
    $coverage_dom->loadXML(Filesystem::readFile($cover_file));

    $modified = $this->getPaths();
    $files = array();
    $reports = array();
    $instrumented = array();
    $executed = array();

    $instrumented = $this->processTags(
      $coverage_dom->getElementsByTagName("instrumented"));
    $executed = $this->processTags(
      $coverage_dom->getElementsByTagName("executed"));

    foreach ($instrumented as $instrument) {
      $absolute_file = $instrument["file"];
      $relative_file = substr($absolute_file, strlen($this->projectRoot) + 1);
      if (!in_array($relative_file, $files)) {
        $files[] = $relative_file;
      }
    }

    foreach ($files as $file) {
      $absolute_file = $this->projectRoot."/".$file;

      // get total line count in file
      $line_count = count(file($absolute_file));

      $coverage = array();
      for ($i = 0; $i < $line_count; $i++) {
        $coverage[$i] = 'N';
      }

      foreach ($instrumented as $instrument) {
        if ($instrument["file"] !== $absolute_file) {
          continue;
        }
        for (
          $i = $instrument["start"];
          $i <= $instrument["end"];
          $i++) {
          $coverage[$i - 1] = 'U';
        }
      }

      foreach ($executed as $execute) {
        if ($execute["file"] !== $absolute_file) {
          continue;
        }
        for (
          $i = $execute["start"];
          $i <= $execute["end"];
          $i++) {
          $coverage[$i - 1] = 'C';
        }
      }

      $reports[$file] = implode($coverage);
    }

    $this->addCachedResults($cover_file, $reports);
    return $reports;
  }
}