<?php

/*
 * Copyright 2012 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Enforces basic spelling.  Spelling inside code is actually pretty hard to
 * get right without false positives.  I take a conservative approach and
 * just use a blacklisted set of words that are commonly spelled
 * incorrectly.
 *
 * @group linter
 */
final class ArcanistSpellingLinter extends ArcanistLinter {

  const LINT_SPELLING_PICKY = 0;
  const LINT_SPELLING_IMPORTANT = 1;

  private $partialWordRules;
  private $wholeWordRules;
  private $severity;

  public function __construct($severity = self::LINT_SPELLING_PICKY) {
    $this->severity = $severity;
    $this->wholeWordRules = ArcanistSpellingDefaultData::getFullWordRules();
    $this->partialWordRules =
      ArcanistSpellingDefaultData::getPartialWordRules();
  }

  public function willLintPaths(array $paths) {
    return;
  }

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

  public function removeLintRule($word) {
    foreach ($this->partialWordRules as $severity=>&$wordlist) {
      unset($wordlist[$word]);
    }

    foreach ($this->wholeWordRules as $severity=>&$wordlist) {
      unset($wordlist[$word]);
    }
  }

  public function addPartialWordRule(
      $incorrect_word,
      $correct_word,
      $severity=self::LINT_SPELLING_IMPORTANT) {
    $this->partialWordRules[$severity][$incorrect_word] = $correct_word;
  }

  public function addWholeWordRule(
      $incorrect_word,
      $correct_word,
      $severity=self::LINT_SPELLING_IMPORTANT) {
    $this->wholeWordRules[$severity][$incorrect_word] = $correct_word;
  }

  public function getLintSeverityMap() {
    return array(
      self::LINT_SPELLING_PICKY => ArcanistLintSeverity::SEVERITY_WARNING,
      self::LINT_SPELLING_IMPORTANT => ArcanistLintSeverity::SEVERITY_ERROR,
    );
  }

  public function getLintNameMap() {
    return array(
      self::LINT_SPELLING_PICKY => 'Possible spelling mistake',
      self::LINT_SPELLING_IMPORTANT => 'Possible spelling mistake',
    );
  }

  public function lintPath($path) {
    foreach ($this->partialWordRules as $severity => $wordlist) {
      if ($severity >= $this->severity) {
        foreach ($wordlist as $misspell => $correct) {
          $this->checkPartialWord($path, $misspell, $correct, $severity);
        }
      }
    }
    foreach ($this->wholeWordRules as $severity => $wordlist) {
      if ($severity >= $this->severity) {
        foreach ($wordlist as $misspell => $correct) {
          $this->checkWholeWord($path, $misspell, $correct, $severity);
        }
      }
    }
  }

  protected function checkPartialWord($path, $word, $correct_word, $severity) {
    $text = $this->getData($path);
    $pos = 0;
    while ($pos < strlen($text)) {
      $next = stripos($text, $word, $pos);
      if ($next === false) {
        return;
      }
      $this->raiseLintAtOffset(
        $next,
        $severity,
        sprintf(
          "Possible spelling error.  You wrote '%s', but did you mean '%s'",
          $word,
          $correct_word
        )
      );
      $pos = $next + 1;
    }
  }

  protected function checkWholeWord($path, $word, $correct_word, $severity) {
    $text = $this->getData($path);
    $matches = array();
    $num_matches = preg_match_all(
      '#\b' . preg_quote($word, '#') . '\b#i',
      $text,
      $matches,
      PREG_OFFSET_CAPTURE
    );
    if (!$num_matches) {
      return;
    }
    foreach ($matches[0] as $match) {
      $this->raiseLintAtOffset(
        $match[1],
        $severity,
        sprintf(
          "Possible spelling error.  You wrote '%s', but did you mean '%s'",
          $word,
          $correct_word
        )
      );
    }
  }
}