// Highlighting text that matches the selection

//

// Defines an option highlightSelectionMatches, which, when enabled,

// will style strings that match the selection throughout the

// document.

//

// The option can be set to true to simply enable it, or to a

// {minChars, style, showToken} object to explicitly configure it.

// minChars is the minimum amount of characters that should be

// selected for the behavior to occur, and style is the token style to

// apply to the matches. This will be prefixed by "cm-" to create an

// actual CSS class name. showToken, when enabled, will cause the

// current token to be highlighted when nothing is selected.



(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";



  var DEFAULT_MIN_CHARS = 2;

  var DEFAULT_TOKEN_STYLE = "matchhighlight";

  var DEFAULT_DELAY = 100;



  function State(options) {

    if (typeof options == "object") {

      this.minChars = options.minChars;

      this.style = options.style;

      this.showToken = options.showToken;

      this.delay = options.delay;

    }

    if (this.style == null) this.style = DEFAULT_TOKEN_STYLE;

    if (this.minChars == null) this.minChars = DEFAULT_MIN_CHARS;

    if (this.delay == null) this.delay = DEFAULT_DELAY;

    this.overlay = this.timeout = null;

  }



  CodeMirror.defineOption("highlightSelectionMatches", false, function(cm, val, old) {

    if (old && old != CodeMirror.Init) {

      var over = cm.state.matchHighlighter.overlay;

      if (over) cm.removeOverlay(over);

      clearTimeout(cm.state.matchHighlighter.timeout);

      cm.state.matchHighlighter = null;

      cm.off("cursorActivity", cursorActivity);

    }

    if (val) {

      cm.state.matchHighlighter = new State(val);

      highlightMatches(cm);

      cm.on("cursorActivity", cursorActivity);

    }

  });



  function cursorActivity(cm) {

    var state = cm.state.matchHighlighter;

    clearTimeout(state.timeout);

    state.timeout = setTimeout(function() {highlightMatches(cm);}, state.delay);

  }



  function highlightMatches(cm) {

    cm.operation(function() {

      var state = cm.state.matchHighlighter;

      if (state.overlay) {

        cm.removeOverlay(state.overlay);

        state.overlay = null;

      }

      if (!cm.somethingSelected() && state.showToken) {

        var re = state.showToken === true ? /[\w$]/ : state.showToken;

        var cur = cm.getCursor(), line = cm.getLine(cur.line), start = cur.ch, end = start;

        while (start && re.test(line.charAt(start - 1))) --start;

        while (end < line.length && re.test(line.charAt(end))) ++end;

        if (start < end)

          cm.addOverlay(state.overlay = makeOverlay(line.slice(start, end), re, state.style));

        return;

      }

      if (cm.getCursor("head").line != cm.getCursor("anchor").line) return;

      var selection = cm.getSelections()[0].replace(/^\s+|\s+$/g, "");

      if (selection.length >= state.minChars)

        cm.addOverlay(state.overlay = makeOverlay(selection, false, state.style));

    });

  }



  function boundariesAround(stream, re) {

    return (!stream.start || !re.test(stream.string.charAt(stream.start - 1))) &&

      (stream.pos == stream.string.length || !re.test(stream.string.charAt(stream.pos)));

  }



  function makeOverlay(query, hasBoundary, style) {

    return {token: function(stream) {

      if (stream.match(query) &&

          (!hasBoundary || boundariesAround(stream, hasBoundary)))

        return style;

      stream.next();

      stream.skipTo(query.charAt(0)) || stream.skipToEnd();

    }};

  }

});

