(function($) {

  $.fn.tokenInput = function(url, options) {
    var settings = $.extend({
      url: url,
      hintText: "Type in a search term",
      noResultsText: "No results",
      searchingText: "Searching...",
      searchDelay: 300,
      maxTokens: null,
      minChars: 3,
      parameters: null
    }, options);

    settings.classes = $.extend({
      tokenList: "token-input-list",
      token: "token-input-token",
      tokenDelete: "token-input-delete-token",
      selectedToken: "token-input-selected-token",
      highlightedToken: "token-input-highlighted-token",
      dropdown: "token-input-dropdown",
      dropdownItem: "token-input-dropdown-item",
      dropdownItem2: "token-input-dropdown-item2",
      selectedDropdownItem: "token-input-selected-dropdown-item",
      inputToken: "token-input-input-token"
    }, options.classes);

    return this.each(function() {
      var list = new $.TokenList(this, settings);
    });
  };

  $.TokenList = function(input, settings) {
    //
    // Variables
    //

    // Input box position "enum"
    var POSITION = {
      BEFORE: 0,
      AFTER: 1,
      END: 2
    };

    // Keys "enum"
    var KEY = {
      BACKSPACE: 8,
      RETURN: 13,
      LEFT: 37,
      UP: 38,
      RIGHT: 39,
      DOWN: 40
    };

    var tokens_full = false;
    var token_count = 0;

    // Save the tokens
    var saved_tokens = [];

    // Basic cache to save on db hits
    var cache = new $.TokenList.Cache();

    // Keep track of the timeout
    var timeout;

    // Create a new text input an attach keyup events
    var input_box = $("<input type=\"text\">")
        .css({
          outline: "none"
        })
        .focus(function() {
          if (!tokens_full) {
            show_dropdown_hint();
          }
        })
        .blur(function() {
          if (!selected_dropdown_item) {
            hide_dropdown();
          }
        })
        .keydown(function(event) {
          var previous_token;
          var next_token;

          switch (event.keyCode) {
            case KEY.LEFT:
            case KEY.RIGHT:
            case KEY.UP:
            case KEY.DOWN:
              if (!$(this).val()) {
                previous_token = input_token.prev();
                next_token = input_token.next();

                if ((previous_token.length && previous_token.get(0) === selected_token) || (next_token.length && next_token.get(0) === selected_token)) {
                  // Check if there is a previous/next token and it is selected
                  if (event.keyCode == KEY.LEFT || event.keyCode == KEY.UP) {
                    deselect_token($(selected_token), POSITION.BEFORE);
                  } else {
                    deselect_token($(selected_token), POSITION.AFTER);
                  }
                } else if ((event.keyCode == KEY.LEFT || event.keyCode == KEY.UP) && previous_token.length) {
                  // We are moving left, select the previous token if it exists
                  select_token($(previous_token.get(0)));
                } else if ((event.keyCode == KEY.RIGHT || event.keyCode == KEY.DOWN) && next_token.length) {
                  // We are moving right, select the next token if it exists
                  select_token($(next_token.get(0)));
                }
              } else {
                var dropdown_item = null;

                if (event.keyCode == KEY.DOWN || event.keyCode == KEY.RIGHT) {
                  dropdown_item = $(selected_dropdown_item).next();
                } else {
                  dropdown_item = $(selected_dropdown_item).prev();
                }

                if (dropdown_item.length) {
                  select_dropdown_item(dropdown_item);
                }
                return false;
              }
              break;

            case KEY.BACKSPACE:
              previous_token = input_token.prev();

              if (!$(this).val().length) {
                if (selected_token) {
                  delete_token($(selected_token));
                } else if (previous_token.length) {
                  select_token($(previous_token.get(0)));
                }

                return false;
              } else if ($(this).val().length == 1) {
                hide_dropdown();
              } else {
                show_dropdown_searching();
                if ($(this).val().length >= settings.minChars) {
                  do_search(1);
                }
              }
              break;

            case KEY.RETURN:
              if (selected_dropdown_item) {
                add_token($(selected_dropdown_item));
                return false;
              }
              break;

            case KEY.ESC:
              hide_dropdown();
              break;

            default:
              if (is_printable_character(event.keyCode)) {
                show_dropdown_searching();
                clearTimeout(timeout);
                timeout = setTimeout(do_search, settings.searchDelay);
              }

              break;
          }
        });

    // Keep a reference to the original input box
    var hidden_input = $(input)
                           .hide()
                           .focus(function() {
                             input_box.focus();
                           })
                           .blur(function() {
                             input_box.blur();
                           })
                           .val("");

    // Keep a reference to the selected token and dropdown item
    var selected_token = null;
    var selected_dropdown_item = null;

    // The list to store the token items in
    var token_list = $("<ul />")
        .addClass(settings.classes.tokenList)
        .insertAfter(hidden_input)
        .click(function(event) {
          var li = get_element_from_event(event, "li");
          if (li && li.get(0) != input_token.get(0)) {
            toggle_select_token(li);
            return false;
          } else {
            input_box.focus();

            if (selected_token) {
              deselect_token($(selected_token), POSITION.END);
            }
          }
        })
        .mouseover(function(event) {
          var li = get_element_from_event(event, "li");
          if (li && selected_token !== this) {
            li.addClass(settings.classes.highlightedToken);
          }
        })
        .mouseout(function(event) {
          var li = get_element_from_event(event, "li");
          if (li && selected_token !== this) {
            li.removeClass(settings.classes.highlightedToken);
          }
        })
        .mousedown(function(event) {
          // Stop user selecting text on tokens
          var li = get_element_from_event(event, "li");
          if (li) {
            return false;
          }
        });


    // The list to store the dropdown items in
    var dropdown = $("<div>")
        .addClass(settings.classes.dropdown)
        .insertAfter(token_list)
        .hide();

    // The token holding the input box
    var input_token = $("<li />")
        .addClass(settings.classes.inputToken)
        .appendTo(token_list)
        .append(input_box);

    //
    // Functions
    //

    function is_printable_character(keycode) {
      if ((keycode >= 48 && keycode <= 90) ||      // 0-1a-z
           (keycode >= 96 && keycode <= 111) ||     // numpad 0-9 + - / * .
           (keycode >= 186 && keycode <= 192) ||    // ; = , - . / ^
           (keycode >= 219 && keycode <= 222)       // ( \ ) '
          ) {
        return true;
      } else {
        return false;
      }
    }

    // Get an element of a particular type from an event (click/mouseover etc)
    function get_element_from_event(event, element_type) {
      var target = $(event.target);
      var element = null;

      if (target.is(element_type)) {
        element = target;
      } else if (target.parent(element_type).length) {
        element = target.parent(element_type + ":first");
      }

      return element;
    }

    // Add a token to the token list
    function add_token(item) {

      var li_data = $.data(item.get(0), "tokeninput");
      var this_token = $("<li><p>" + li_data.name + "</p> </li>")
            .addClass(settings.classes.token)
            .insertBefore(input_token);

      $("<span>x</span>")
            .addClass(settings.classes.tokenDelete)
            .appendTo(this_token)
            .click(function() {
              delete_token($(this).parent());
              return false;
            });

      $.data(this_token.get(0), "tokeninput", { "id": li_data.id, "name": li_data.name });

      // Clear input box and make sure it keeps focus
      input_box
            .val("")
            .focus();

      token_count++;

      if (token_count == settings.maxTokens) {
        tokens_full = true;
        input_box.hide();
      }

      // Don't show the help dropdown, they've got the idea
      hide_dropdown();

      // Save this token id
      var id_string = li_data.id + ","
      hidden_input.val(hidden_input.val() + id_string);
    }

    // Select a token in the token list
    function select_token(token) {
      token.addClass(settings.classes.selectedToken);
      selected_token = token.get(0);

      // Hide input box
      input_box.val("");

      // Hide dropdown if it is visible (eg if we clicked to select token)
      hide_dropdown();
    }

    // Deselect a token in the token list
    function deselect_token(token, position) {
      token.removeClass(settings.classes.selectedToken);
      selected_token = null;

      if (position == POSITION.BEFORE) {
        input_token.insertBefore(token);
      } else if (position == POSITION.AFTER) {
        input_token.insertAfter(token);
      } else {
        input_token.appendTo(token_list);
      }

      // Show the input box and give it focus again
      input_box.focus();
    }

    // Toggle selection of a token in the token list
    function toggle_select_token(token) {
      if (selected_token == token.get(0)) {
        deselect_token(token, POSITION.END);
      } else {
        if (selected_token) {
          deselect_token($(selected_token), POSITION.END);
        }
        select_token(token);
      }
    }

    // Delete a token from the token list
    function delete_token(token) {
      // Remove the id from the saved list
      var token_data = $.data(token.get(0), "tokeninput");
      //saved_tokens.splice($.inArray(saved_tokens, token_data.id), 1);

      // Delete the token
      token.remove();
      selected_token = null;

      if (settings.maxTokens) {
        token_count--;
        tokens_full = false;
        input_box.show();
      }

      // Show the input box and give it focus again
      input_box.focus();

      // Delete this token's id from hidden input
      var str = hidden_input.val()
      var start = str.indexOf(token_data.id + ",");
      var end = str.indexOf(",", start) + 1;

      if (end >= str.length) {
        hidden_input.val(str.slice(0, start));
      } else {
        hidden_input.val(str.slice(0, start) + str.slice(end, str.length));
      }
    }

    // Hide and clear the results dropdown
    function hide_dropdown() {
      dropdown.hide().empty();
      selected_dropdown_item = null;
    }

    function show_dropdown_searching() {
      dropdown
            .html("<p>" + settings.searchingText + "</p>")
            .show();
    }

    function show_dropdown_hint() {
      dropdown
            .html("<p>" + settings.hintText + "</p>")
            .show();
    }

    // Highlight the query part of the search term
    function highlight_term(value, term) {
      return value.replace(new RegExp("(?![^&;]+;)(?!<[^<>]*)(" + term + ")(?![^<>]*>)(?![^&;]+;)", "gi"), "<em>$1</em>");
    }

    // Populate the results dropdown with some results
    function populate_dropdown(query, results) {
      if (results.length) {
        dropdown.empty();
        var dropdown_ul = $("<ul>")
                .appendTo(dropdown)
                .mouseover(function(event) {
                  select_dropdown_item(get_element_from_event(event, "li"));
                })
                .click(function(event) {
                  add_token(get_element_from_event(event, "li"));
                })
                .mousedown(function(event) {
                  // Stop user selecting text on tokens
                  return false;
                })
                .hide();

        for (var i in results) {
          if (results.hasOwnProperty(i)) {
            var this_li = $("<li>" + highlight_term(results[i].name, query) + "</li>")
                                      .appendTo(dropdown_ul);

            if (i % 2) {
              this_li.addClass(settings.classes.dropdownItem);
            } else {
              this_li.addClass(settings.classes.dropdownItem2);
            }

            if (i == 0) {
              select_dropdown_item(this_li);
            }

            $.data(this_li.get(0), "tokeninput", { "id": results[i].id, "name": results[i].name });
          }
        }

        dropdown.show();
        dropdown_ul.slideDown("fast");

      } else {
        dropdown
                .html("<p>" + settings.noResultsText + "</p>")
                .show();
      }
    }

    // Highlight an item in the results dropdown
    function select_dropdown_item(item) {
      if (item) {
        if (selected_dropdown_item) {
          deselect_dropdown_item($(selected_dropdown_item));
        }

        item.addClass(settings.classes.selectedDropdownItem);
        selected_dropdown_item = item.get(0);
      }
    }

    // Remove highlighting from an item in the results dropdown
    function deselect_dropdown_item(item) {
      item.removeClass(settings.classes.selectedDropdownItem);
      selected_dropdown_item = null;
    }

    // Do a search
    function do_search(trim_last_char) {
      var query = input_box.val().toLowerCase();
      if (query.length < settings.minChars)
        return;

      if (trim_last_char == 1) {
        query = query.substring(0, query.length - 1);
      }

      if (query && query.length) {
        if (selected_token) {
          deselect_token($(selected_token), POSITION.AFTER);
        }

        var cached_results = cache.get(query);
        if (cached_results) {
          populate_dropdown(query, cached_results);
        } else {
          var query_string = (settings.url.indexOf('?') == -1 ? "?" : "&") + "q=" + query;
          if (settings.parameters != null) {
            $.each(settings.parameters, function(key, val) {
              query_string += "&" + key + "=" + val;
            });
          }
          $.get(settings.url + query_string, {}, function(results) {
            cache.add(query, results);
            populate_dropdown(query, results);
          }, "json");
        }
      }
    }
  };

  // Really basic cache for the results
  $.TokenList.Cache = function(options) {
    var settings = $.extend({
      max_size: 10
    }, options);

    var data = {};
    var size = 0;

    var flush = function() {
      data = {};
      size = 0;
    };

    this.add = function(query, results) {
      if (size > settings.max_size) {
        flush();
      }

      if (!data[query]) {
        size++;
      }

      data[query] = results;
    };

    this.get = function(query) {
      return data[query];
    };
  };

})(jQuery);