/**
 * jQuery Formset 1.5-pre
 * @author Stanislaus Madueke (stan DOT madueke AT gmail DOT com)
 * @requires jQuery 1.2.6 or later
 *
 * Copyright (c) 2009, Stanislaus Madueke
 * All rights reserved.
 *
 * Licensed under the New BSD License
 * See: http://www.opensource.org/licenses/bsd-license.php
 */
;(function ($) {
  $.fn.formset = function (opts) {
    var options = $.extend({}, $.fn.formset.defaults, opts)
    var flatExtraClasses = options.extraClasses.join(' ')
    var totalForms = $('#id_' + options.prefix + '-TOTAL_FORMS')
    var maxForms = $('#id_' + options.prefix + '-MAX_NUM_FORMS')
    var minForms = $('#id_' + options.prefix + '-MIN_NUM_FORMS')
    var childElementSelector = 'input,select,textarea,label,div'
    var $$ = $(this)

    var applyExtraClasses = function (row, ndx) {
      if (options.extraClasses) {
        row.removeClass(flatExtraClasses)
        row.addClass(options.extraClasses[ndx % options.extraClasses.length])
      }
    }

    var updateElementIndex = function (elem, prefix, ndx) {
      var idRegex = new RegExp(prefix + '-(\\d+|__prefix__)-')
      var replacement = prefix + '-' + ndx + '-'
      if (elem.attr('for')) elem.attr('for', elem.attr('for').replace(idRegex, replacement))
      if (elem.attr('id')) elem.attr('id', elem.attr('id').replace(idRegex, replacement))
      if (elem.attr('name')) elem.attr('name', elem.attr('name').replace(idRegex, replacement))
    }

    var hasChildElements = function (row) {
      return row.find(childElementSelector).length > 0
    }

    var showAddButton = function () {
      return maxForms.length === 0 || // For Django versions pre 1.2
                    (maxForms.val() === '' || (maxForms.val() - totalForms.val() > 0))
    }

    /**
            * Indicates whether delete link(s) can be displayed - when total forms > min forms
            */
    var showDeleteLinks = function () {
      return minForms.length === 0 || // For Django versions pre 1.7
                    (minForms.val() === '' || (totalForms.val() - minForms.val() > 0))
    }

    var insertDeleteLink = function (row) {
      var delCssSelector = $.trim(options.deleteCssClass).replace(/\s+/g, '.')
      var addCssSelector = $.trim(options.addCssClass).replace(/\s+/g, '.')

      var delButtonHTML = '<a class="' + options.deleteCssClass + '" href="javascript:void(0)">' + options.deleteText + '</a>'
      if (options.deleteContainerClass) {
        // If we have a specific container for the remove button,
        // place it as the last child of that container:
        row.find('[class*="' + options.deleteContainerClass + '"]').append(delButtonHTML)
      } else if (row.is('TR')) {
        // If the forms are laid out in table rows, insert
        // the remove button into the last table cell:
        row.children('td:last').append(delButtonHTML)
      } else if (row.is('UL') || row.is('OL')) {
        // If they're laid out as an ordered/unordered list,
        // insert an <li> after the last list item:
        row.append('<li>' + delButtonHTML + '</li>')
      } else {
        // Otherwise, just insert the remove button as the
        // last child element of the form's container:
        row.append(delButtonHTML)
      }

      // Check if we're under the minimum number of forms - not to display delete link at rendering
      if (!showDeleteLinks()) {
        row.find('a.' + delCssSelector).hide()
      }

      row.find('a.' + delCssSelector).click(function () {
        var row = $(this).parents('.' + options.formCssClass)
        var del = row.find('input:hidden[id $= "-DELETE"]')
        var buttonRow = row.siblings('a.' + addCssSelector + ', .' + options.formCssClass + '-add')
        var forms
        if (del.length) {
          // We're dealing with an inline formset.
          // Rather than remove this form from the DOM, we'll mark it as deleted
          // and hide it, then let Django handle the deleting:
          del.val('on')
          row.hide()
          forms = $('.' + options.formCssClass).not(':hidden')
        } else {
          row.remove()
          // Update the TOTAL_FORMS count:
          forms = $('.' + options.formCssClass).not('.formset-custom-template')
          totalForms.val(forms.length)
        }
        for (var i = 0, formCount = forms.length; i < formCount; i++) {
          // Apply `extraClasses` to form rows so they're nicely alternating:
          applyExtraClasses(forms.eq(i), i)
          if (!del.length) {
            // Also update names and IDs for all child controls (if this isn't
            // a delete-able inline formset) so they remain in sequence:
            forms.eq(i).find(childElementSelector).each(function () {
              updateElementIndex($(this), options.prefix, i)
            })
          }
        }
        // Check if we've reached the minimum number of forms - hide all delete link(s)
        if (!showDeleteLinks()) {
          $('a.' + delCssSelector).each(function () { $(this).hide() })
        }
        // Check if we need to show the add button:
        if (buttonRow.is(':hidden') && showAddButton()) buttonRow.show()
        // If a post-delete callback was provided, call it with the deleted form:
        if (options.removed) options.removed(row)
        return false
      })
    }

    $$.each(function (i) {
      var row = $(this)
      var del = row.find('input:checkbox[id $= "-DELETE"]')
      if (del.length) {
        // If you specify "can_delete = True" when creating an inline formset,
        // Django adds a checkbox to each form in the formset.
        // Replace the default checkbox with a hidden field:
        if (del.is(':checked')) {
          // If an inline formset containing deleted forms fails validation, make sure
          // we keep the forms hidden (thanks for the bug report and suggested fix Mike)
          del.before('<input type="hidden" name="' + del.attr('name') + '" id="' + del.attr('id') + '" value="on" />')
          row.hide()
        } else {
          del.before('<input type="hidden" name="' + del.attr('name') + '" id="' + del.attr('id') + '" />')
        }
        // Hide any labels associated with the DELETE checkbox:
        $('label[for="' + del.attr('id') + '"]').hide()
        del.remove()
      }
      if (hasChildElements(row)) {
        row.addClass(options.formCssClass)
        if (row.is(':visible')) {
          insertDeleteLink(row)
          applyExtraClasses(row, i)
        }
      }
    })

    if ($$.length) {
      var hideAddButton = !showAddButton()
      var addButton; var template
      if (options.formTemplate) {
        // If a form template was specified, we'll clone it to generate new form instances:
        template = (options.formTemplate instanceof $) ? options.formTemplate : $(options.formTemplate)
        template.removeAttr('id').addClass(options.formCssClass + ' formset-custom-template')
        template.find(childElementSelector).each(function () {
          updateElementIndex($(this), options.prefix, '__prefix__')
        })
        insertDeleteLink(template)
      } else {
        // Otherwise, use the last form in the formset; this works much better if you've got
        // extra (>= 1) forms (thnaks to justhamade for pointing this out):
        if (options.hideLastAddForm) $('.' + options.formCssClass + ':last').hide()
        template = $('.' + options.formCssClass + ':last').clone(true).removeAttr('id')
        template.find('input:hidden[id $= "-DELETE"]').remove()
        // Clear all cloned fields, except those the user wants to keep (thanks to brunogola for the suggestion):
        template.find(childElementSelector).not(options.keepFieldValues).each(function () {
          var elem = $(this)
          // If this is a checkbox or radiobutton, uncheck it.
          // This fixes Issue 1, reported by Wilson.Andrew.J:
          if (elem.is('input:checkbox') || elem.is('input:radio')) {
            elem.attr('checked', false)
          } else {
            elem.val('')
          }
        })
      }
      // FIXME: Perhaps using $.data would be a better idea?
      options.formTemplate = template

      var addButtonHTML = '<a class="' + options.addCssClass + '" href="javascript:void(0)">' + options.addText + '</a>'
      if (options.addContainerClass) {
        // If we have a specific container for the "add" button,
        // place it as the last child of that container:
        var addContainer = $('[class*="' + options.addContainerClass + '"')
        addContainer.append(addButtonHTML)
        addButton = addContainer.find('[class="' + options.addCssClass + '"]')
      } else if ($$.is('TR')) {
        // If forms are laid out as table rows, insert the
        // "add" button in a new table row:
        var numCols = $$.eq(0).children().length // This is a bit of an assumption :|
        var buttonRow = $('<tr><td colspan="' + numCols + '">' + addButtonHTML + '</tr>').addClass(options.formCssClass + '-add')
        $$.parent().append(buttonRow)
        addButton = buttonRow.find('a')
      } else {
        // Otherwise, insert it immediately after the last form:
        $$.filter(':last').after(addButtonHTML)
        addButton = $$.filter(':last').next()
      }

      if (hideAddButton) addButton.hide()

      addButton.click(function () {
        var formCount = parseInt(totalForms.val())
        var row = options.formTemplate.clone(true).removeClass('formset-custom-template')
        var buttonRow = $($(this).parents('tr.' + options.formCssClass + '-add').get(0) || this)
        var delCssSelector = $.trim(options.deleteCssClass).replace(/\s+/g, '.')
        applyExtraClasses(row, formCount)
        row.insertBefore(buttonRow).show()
        row.find(childElementSelector).each(function () {
          updateElementIndex($(this), options.prefix, formCount)
        })
        totalForms.val(formCount + 1)
        // Check if we're above the minimum allowed number of forms -> show all delete link(s)
        if (showDeleteLinks()) {
          $('a.' + delCssSelector).each(function () { $(this).show() })
        }
        // Check if we've exceeded the maximum allowed number of forms:
        if (!showAddButton()) buttonRow.hide()
        // If a post-add callback was supplied, call it with the added form:
        if (options.added) options.added(row)
        return false
      })
    }

    return $$
  }

  /* Setup plugin defaults */
  $.fn.formset.defaults = {
    prefix: 'form', // The form prefix for your django formset
    formTemplate: null, // The jQuery selection cloned to generate new form instances
    addText: 'add another', // Text for the add link
    deleteText: 'remove', // Text for the delete link
    addContainerClass: null, // Container CSS class for the add link
    deleteContainerClass: null, // Container CSS class for the delete link
    addCssClass: 'add-row', // CSS class applied to the add link
    deleteCssClass: 'delete-row', // CSS class applied to the delete link
    formCssClass: 'dynamic-form', // CSS class applied to each form in a formset
    extraClasses: [], // Additional CSS classes, which will be applied to each form in turn
    keepFieldValues: '', // jQuery selector for fields whose values should be kept when the form is cloned
    added: null, // Function called each time a new form is added
    removed: null, // Function called each time a form is deleted
    hideLastAddForm: false // When set to true, hide last empty add form (becomes visible when clicking on add button)
  }
})(jQuery)