var initDjangoHStoreWidget = function (hstore_field_name, inline_prefix) {
  // ignore inline templates
  // if hstore_field_name contains "__prefix__"
  if (hstore_field_name.indexOf("__prefix__") > -1) {
    return;
  }

  var $ = django.jQuery;

  // processing inlines
  if (hstore_field_name.indexOf("inline") > -1) {
    var inlineClass = $("#id_" + hstore_field_name)
      .parents(".inline-related, .grp-group")
      .attr("class");
    // if using TabularInlines stop here
    // TabularInlines not supported
    if (inlineClass.indexOf("tabular") > -1) {
      return;
    }
  }

  // reusable function that retrieves a template even if ID is not correct
  // (written to support inlines)
  var retrieveTemplate = function (template_name, field_name) {
    var specific_template = $("#" + template_name + "-" + field_name);
    // if found specific template return that
    if (specific_template.length) {
      return specific_template.html();
    } else {
      // get fallback template
      var html = $("." + template_name + "-inline").html();
      // replace all occurrences of __prefix__ with field_name
      // and return
      html = html.replace(/__prefix__/g, inline_prefix);
      return html;
    }
  };

  // reusable function that compiles the UI
  var compileUI = function (params) {
    var hstore_field_id = "id_" + hstore_field_name,
      original_textarea = $("#" + hstore_field_id),
      original_value = original_textarea.val(),
      original_container = original_textarea
        .parents(".form-row, .grp-row")
        .eq(0),
      errorHtml = original_container.find(".errorlist").html(),
      json_data = {};

    if (original_value !== "") {
      // manage case in which textarea is blank
      try {
        json_data = JSON.parse(original_value);
      } catch (e) {
        alert("invalid JSON:\n" + e);
        return false;
      }
    }

    var hstore_field_data = {
        id: hstore_field_id,
        label: original_container.find("label").text(),
        name: hstore_field_name,
        value: original_textarea.val(),
        help: original_container.find(".grp-help, .help").text(),
        errors: errorHtml,
        data: json_data,
      },
      // compile template
      ui_html = retrieveTemplate("hstore-ui-template", hstore_field_name),
      compiled_ui_html = _.template(ui_html, hstore_field_data);

    // this is just to DRY up a bit
    if (params && params.replace_original === true) {
      // remove original textarea to avoid having two textareas with same ID
      original_textarea.remove();
      // inject compiled template and hide original
      original_container.after(compiled_ui_html).hide();
    }

    return compiled_ui_html;
  };

  // generate UI
  compileUI({ replace_original: true });

  // cache other objects that we'll reuse
  var row_html = retrieveTemplate("hstore-row-template", hstore_field_name),
    empty_row = _.template(row_html, { key: "", value: "" }),
    $hstore = $("#id_" + hstore_field_name).parents(".hstore");

  // reusable function that updates the textarea value
  var updateTextarea = function (container) {
    // init empty json object
    var new_value = {},
      raw_textarea = container.find("textarea"),
      rows = container.find(".form-row, .grp-row");

    // loop over each object and populate json
    rows.each(function () {
      var inputs = $(this).find("input"),
        key = $(this).find(".hs-key").val(),
        value = $(this).find(".hs-val").val();
      new_value[key] = value;
    });

    // update textarea value
    $(raw_textarea).val(JSON.stringify(new_value, null, 4));
  };

  // remove row link
  $hstore.delegate("a.remove-row", "click", function (e) {
    e.preventDefault();
    // cache container jquery object before $(this) gets removed
    $(this).parents(".form-row, .grp-row").eq(0).remove();
    updateTextarea($hstore);
  });

  // add row link
  $hstore.delegate("a.hs-add-row, .hs-add-row a", "click", function (e) {
    e.preventDefault();
    $hstore.find(".hstore-rows").append(empty_row);
    $(".django-select2").select2();
    $("select").on("select2:close", function () {
      $(this).focus();
    });
  });

  // toggle textarea link
  $hstore.delegate(".hstore-toggle-txtarea", "click", function (e) {
    e.preventDefault();

    var raw_textarea = $hstore.find(".hstore-textarea"),
      hstore_rows = $hstore.find(".hstore-rows"),
      add_row = $hstore.find(".hs-add-row");

    if (raw_textarea.is(":visible")) {
      var compiled_ui = compileUI();

      // in case of JSON error
      if (compiled_ui === false) {
        return;
      }

      // jquery < 1.8
      try {
        var $ui = $(compiled_ui);
      } catch (e) {
        // jquery >= 1.8
        var $ui = $($.parseHTML(compiled_ui));
      }

      // update rows with only relevant content
      hstore_rows.html($ui.find(".hstore-rows").html());

      raw_textarea.hide();
      hstore_rows.show();
      add_row.show();

      $(".django-select2").select2();
    } else {
      raw_textarea.show();
      hstore_rows.hide();
      add_row.hide();
    }
  });

  // update textarea whenever a field changes
  $hstore.delegate(".hs-val", "keyup propertychange", function () {
    updateTextarea($hstore);
  });

  $hstore.delegate(".hs-key", "change", function () {
    updateTextarea($hstore);
  });
};
window.addEventListener("load", function () {
  // support inlines
  // bind only once
  if (django.hstoreWidgetBoundInlines === undefined) {
    var $ = django.jQuery;
    $(
      ".grp-group .grp-add-handler, .inline-group .hs-add-row a, .inline-group .add-row"
    ).click(function (e) {
      var hstore_original_textareas = $(this)
        .parents(".grp-group, .inline-group")
        .eq(0)
        .find(".hstore-original-textarea");
      // if module contains .hstore-original-textarea
      if (hstore_original_textareas.length > 0) {
        // loop over each inline
        $(this)
          .parents(".grp-group, .inline-group")
          .find(".grp-items div.grp-dynamic-form, .inline-related")
          .each(function (e, i) {
            var prefix = i;
            // loop each textarea
            $(this)
              .find(".hstore-original-textarea")
              .each(function (e, i) {
                // cache field name
                var field_name = $(this).attr("name");
                // ignore templates
                // if name attribute contains __prefix__
                if (field_name.indexOf("prefix") > -1) {
                  // skip to next
                  return;
                }
                initDjangoHStoreWidget(field_name, prefix);
              });
          });
      }
    });
    django.hstoreWidgetBoundInlines = true;
  }
});