// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: http://codemirror.net/LICENSE
/**
 * CodeMirror 任意单词提示助手（hint: "anyword"）
 * 基于文档内已有的单词生成补全建议，支持自定义单词规则和搜索范围
 */
(function(mod) {
  if (typeof exports == "object" && typeof module == "object") // CommonJS
    mod(require("../../lib/codemirror"));
  else if (typeof define == "function" && define.amd) // AMD
    define(["../../lib/codemirror"], mod);
  else // Plain browser env
    mod(CodeMirror);
})(function(CodeMirror) {
  "use strict";
  // 默认配置：单词匹配正则（字母、数字、下划线、$）、搜索范围（前后各500行
  var WORD = /[\w$]+/, RANGE = 500;
  /**
   * 注册“任意单词提示”助手（hint: "anyword"）
   * 功能：提取文档内符合规则的单词，生成以当前输入为前缀的补全建议
   * @param {CodeMirror} editor - 编辑器实例
   * @param {Object} [options] - 配置项（word: 单词正则，range: 搜索范围）
   * @return {Object} 补全结果（list: 建议列表，from/to: 补全替换范围）
   */
  CodeMirror.registerHelper("hint", "anyword", function(editor, options) {
    var word = options && options.word || WORD;
    var range = options && options.range || RANGE;
    var cur = editor.getCursor(), curLine = editor.getLine(cur.line);
    var end = cur.ch, start = end;
    while (start && word.test(curLine.charAt(start - 1))) --start;
    var curWord = start != end && curLine.slice(start, end);

    var list = [], seen = {};
    var re = new RegExp(word.source, "g");
    for (var dir = -1; dir <= 1; dir += 2) {
      var line = cur.line, endLine = Math.min(Math.max(line + dir * range, editor.firstLine()), editor.lastLine()) + dir;
      for (; line != endLine; line += dir) {
        var text = editor.getLine(line), m;
        while (m = re.exec(text)) {
          if (line == cur.line && m[0] === curWord) continue;
          if ((!curWord || m[0].lastIndexOf(curWord, 0) == 0) && !Object.prototype.hasOwnProperty.call(seen, m[0])) {
            seen[m[0]] = true;
            list.push(m[0]);
          }
        }
      }
    }
    return {list: list, from: CodeMirror.Pos(cur.line, start), to: CodeMirror.Pos(cur.line, end)};
  });
});
