<?php

final class ArcanistPhutilXHPASTLinter extends ArcanistBaseXHPASTLinter {

  const LINT_ARRAY_COMBINE           = 2;
  const LINT_DEPRECATED_FUNCTION     = 3;
  const LINT_UNSAFE_DYNAMIC_STRING   = 4;

  private $deprecatedFunctions = array();
  private $dynamicStringFunctions = array();
  private $dynamicStringClasses = array();

  public function setDeprecatedFunctions($map) {
    $this->deprecatedFunctions = $map;
    return $this;
  }

  public function setDynamicStringFunctions($map) {
    $this->dynamicStringFunctions = $map;
    return $this;
  }

  public function setDynamicStringClasses($map) {
    $this->dynamicStringClasses = $map;
    return $this;
  }

  public function getLintNameMap() {
    return array(
      self::LINT_ARRAY_COMBINE           => 'array_combine() Unreliable',
      self::LINT_DEPRECATED_FUNCTION     => 'Use of Deprecated Function',
      self::LINT_UNSAFE_DYNAMIC_STRING   => 'Unsafe Usage of Dynamic String',
    );
  }

  public function getLintSeverityMap() {
    $warning = ArcanistLintSeverity::SEVERITY_WARNING;
    return array(
      self::LINT_ARRAY_COMBINE           => $warning,
      self::LINT_DEPRECATED_FUNCTION     => $warning,
      self::LINT_UNSAFE_DYNAMIC_STRING   => $warning,
    );
  }

  public function getLinterName() {
    return 'PHLXHP';
  }

  public function getLinterConfigurationName() {
    return 'phutil-xhpast';
  }

  public function getCacheVersion() {
    $version = '2';
    $path = xhpast_get_binary_path();
    if (Filesystem::pathExists($path)) {
      $version .= '-'.md5_file($path);
    }
    return $version;
  }

  public function getLinterConfigurationOptions() {
    $options = array(
      'phutil-xhpast.deprecated.functions' => array(
        'type' => 'optional map<string, string>',
        'help' => pht(
          'Functions which should should be considered deprecated.'),
      ),
      'phutil-xhpast.dynamic-string.functions' => array(
        'type' => 'optional map<string, string>',
        'help' => pht(
          'Functions which should should not be used because they represent '.
          'the unsafe usage of dynamic strings.'),
      ),
      'phutil-xhpast.dynamic-string.classes' => array(
        'type' => 'optional map<string, string>',
        'help' => pht(
          'Classes which should should not be used because they represent the '.
          'unsafe usage of dynamic strings.'),
      ),
    );

    return $options + parent::getLinterConfigurationOptions();
  }

  public function setLinterConfigurationValue($key, $value) {
    switch ($key) {
      case 'phutil-xhpast.deprecated.functions':
        $this->setDeprecatedFunctions($value);
        return;
      case 'phutil-xhpast.dynamic-string.functions':
        $this->setDynamicStringFunctions($value);
        return;
      case 'phutil-xhpast.dynamic-string.classes':
        $this->setDynamicStringClasses($value);
        return;
    }

    return parent::setLinterConfigurationValue($key, $value);
  }

  protected function resolveFuture($path, Future $future) {
    $tree = $this->getXHPASTLinter()->getXHPASTTreeForPath($path);
    if (!$tree) {
      return;
    }

    $root = $tree->getRootNode();

    $method_codes = array(
      'lintArrayCombine' => self::LINT_ARRAY_COMBINE,
      'lintUnsafeDynamicString' => self::LINT_UNSAFE_DYNAMIC_STRING,
      'lintDeprecatedFunctions' => self::LINT_DEPRECATED_FUNCTION,
    );

    foreach ($method_codes as $method => $codes) {
      foreach ((array)$codes as $code) {
        if ($this->isCodeEnabled($code)) {
          call_user_func(array($this, $method), $root);
          break;
        }
      }
    }
  }


  private function lintUnsafeDynamicString(XHPASTNode $root) {
    $safe = $this->dynamicStringFunctions + array(
      'pht' => 0,

      'hsprintf' => 0,
      'jsprintf' => 0,

      'hgsprintf' => 0,

      'csprintf' => 0,
      'vcsprintf' => 0,
      'execx' => 0,
      'exec_manual' => 0,
      'phutil_passthru' => 0,

      'qsprintf' => 1,
      'vqsprintf' => 1,
      'queryfx' => 1,
      'vqueryfx' => 1,
      'queryfx_all' => 1,
      'vqueryfx_all' => 1,
      'queryfx_one' => 1,
    );

    $calls = $root->selectDescendantsOfType('n_FUNCTION_CALL');
    $this->lintUnsafeDynamicStringCall($calls, $safe);

    $safe = $this->dynamicStringClasses + array(
      'ExecFuture' => 0,
    );

    $news = $root->selectDescendantsOfType('n_NEW');
    $this->lintUnsafeDynamicStringCall($news, $safe);
  }

  private function lintUnsafeDynamicStringCall(
    AASTNodeList $calls,
    array $safe) {

    $safe = array_combine(
      array_map('strtolower', array_keys($safe)),
      $safe);

    foreach ($calls as $call) {
      $name = $call->getChildByIndex(0)->getConcreteString();
      $param = idx($safe, strtolower($name));

      if ($param === null) {
        continue;
      }

      $parameters = $call->getChildByIndex(1);
      if (count($parameters->getChildren()) <= $param) {
        continue;
      }

      $identifier = $parameters->getChildByIndex($param);
      if (!$identifier->isConstantString()) {
        $this->raiseLintAtNode(
          $call,
          self::LINT_UNSAFE_DYNAMIC_STRING,
          "Parameter ".($param + 1)." of {$name}() should be a scalar string, ".
            "otherwise it's not safe.");
      }
    }
  }


  private function lintArrayCombine(XHPASTNode $root) {
    $function_calls = $root->selectDescendantsOfType('n_FUNCTION_CALL');
    foreach ($function_calls as $call) {
      $name = $call->getChildByIndex(0)->getConcreteString();
      if (strcasecmp($name, 'array_combine') == 0) {
        $parameter_list = $call->getChildOfType(1, 'n_CALL_PARAMETER_LIST');
        if (count($parameter_list->getChildren()) !== 2) {
          // Wrong number of parameters, but raise that elsewhere if we want.
          continue;
        }

        $first = $parameter_list->getChildByIndex(0);
        $second = $parameter_list->getChildByIndex(1);

        if ($first->getConcreteString() == $second->getConcreteString()) {
          $this->raiseLintAtNode(
            $call,
            self::LINT_ARRAY_COMBINE,
            'Prior to PHP 5.4, array_combine() fails when given empty '.
            'arrays. Prefer to write array_combine(x, x) as array_fuse(x).');
        }
      }
    }
  }

  private function lintDeprecatedFunctions(XHPASTNode $root) {
    $map = $this->deprecatedFunctions;

    $function_calls = $root->selectDescendantsOfType('n_FUNCTION_CALL');
    foreach ($function_calls as $call) {
      $name = $call->getChildByIndex(0)->getConcreteString();

      $name = strtolower($name);
      if (empty($map[$name])) {
        continue;
      }

      $this->raiseLintAtNode(
        $call,
        self::LINT_DEPRECATED_FUNCTION,
        $map[$name]);
    }
  }

}