.gitignore

@@ -5,6 +5,7 @@
 /gadjo.egg-info
 /gadjo/locale/fr/LC_MESSAGES/django.mo
 /gadjo/static/css/gadjo.css
+/gadjo/static/css/gadjo.multiselectwidget.css
 /gadjo/static/css/icons
 node_modules
 MANIFEST

gadjo/forms/widgets.py

@@ -0,0 +1,46 @@
+import django
+from django import forms
+
+
+class MultiSelectWidget(forms.MultiWidget):
+    template_name = 'gadjo/widgets/multiselectwidget.html'
+
+    class Media:
+        js = ('js/gadjo.multiselectwidget.js',)
+        css = {'all': ('css/gadjo.multiselectwidget.css',)}
+
+    def __init__(self, attrs=None):
+        self.attrs = attrs
+        widgets = [forms.Select(attrs=attrs)]
+        super().__init__(widgets, attrs)
+
+    def get_context(self, name, value, attrs):
+        if not isinstance(value, list):
+            value = [value]
+
+        self.widgets = []
+        for _ in range(max(len(value), 1)):
+            self.widgets.append(forms.Select(attrs=self.attrs, choices=self.choices))
+
+        # all subwidgets must have the same name
+        if django.VERSION >= (3, 1):
+            self.widgets_names = [''] * len(self.widgets)
+            return super().get_context(name, value, attrs)
+        else:
+            context = super().get_context(name, value, attrs)
+            subwidgets = context['widget']['subwidgets']
+            for widget in subwidgets:
+                widget['name'] = widget['name'].rsplit('_', 1)[0]
+            return context
+
+    def decompress(self, value):
+        return value or []
+
+    def value_from_datadict(self, data, files, name):
+        values = [x for x in data.getlist(name) if x]
+
+        # remove duplicates while keeping order
+        return list(dict.fromkeys(values))
+
+    def id_for_label(self, id_):
+        return id_

gadjo/static/css/gadjo.multiselectwidget.scss

@@ -0,0 +1,35 @@
+.gadjo-multi-select-widget {
+	&--field {
+		  margin-bottom: 0.2em;
+	}
+
+	&--select-button-container {
+		  display: flex;
+		  gap: 0.5em;
+	}
+
+	&--field {
+		select {
+			  min-width: 0;
+		}
+
+		button {
+			margin-top: auto;
+			margin-bottom: auto;
+		}
+
+		&:first-of-type .gadjo-multi-select-widget--button-remove {
+			display: none;
+		}
+	}
+
+	&--button-add::before {
+		content: "\f067"; /* plus */
+		font-family: FontAwesome;
+	}
+
+	&--button-remove::before {
+		content: "\f068"; /* minus */
+		font-family: FontAwesome;
+	}
+}

gadjo/static/js/gadjo.multiselectwidget.js

@@ -0,0 +1,58 @@
+const multiSelectWidget = (function () {
+  const addRow = function () {
+    const widget = this.closest('.gadjo-multi-select-widget')
+    event.preventDefault()
+
+    /* get last row node */
+    const rows = widget.querySelectorAll('.gadjo-multi-select-widget--field')
+    const lastRow = rows[rows.length - 1]
+
+    /* clone the row */
+    const newRow = lastRow.cloneNode(true)
+
+    /* set new label and ids */
+    const rowLabel = widget.dataset.rowLabel
+    const newLabel = rowLabel + ' ' + rows.length
+    newRow.querySelector('label').textContent = newLabel
+
+    const rowId = widget.dataset.rowId
+    const newId = rowId + '_' + rows.length
+    newRow.querySelector('label').setAttribute('for', newId)
+    newRow.querySelector('select').setAttribute('id', newId)
+
+    /* add new row after the last row */
+    lastRow.parentNode.insertBefore(newRow, lastRow.nextSibling)
+
+    const removeButton = newRow.querySelector('.gadjo-multi-select-widget--button-remove')
+    removeButton.addEventListener('click', removeRow)
+  }
+
+  const removeRow = function (event) {
+    event.preventDefault()
+    const field = this.closest('.content')
+    let row = this.closest('.gadjo-multi-select-widget--field')
+    row.remove()
+    field.dispatchEvent(new Event('change'))
+  }
+
+  const init = function (container) {
+    const widgets = container.querySelectorAll('.gadjo-multi-select-widget')
+    if (!widgets.length) return
+
+    widgets.forEach(function (widget) {
+      const deletBtn = widget.querySelector('.gadjo-multi-select-widget--button-remove')
+      const addBtn = widget.querySelector('.gadjo-multi-select-widget--button-add')
+
+      addBtn.removeEventListener('click', addRow)
+      addBtn.addEventListener('click', addRow)
+      deletBtn.removeEventListener('click', removeRow)
+      deletBtn.addEventListener('click', removeRow)
+    })
+  }
+
+  return {
+    init,
+  }
+})()
+
+window.addEventListener('DOMContentLoaded', () => multiSelectWidget.init(document))

gadjo/templates/gadjo/widgets/multiselectwidget.html

@@ -0,0 +1,17 @@
+{% load i18n %}
+
+<div class="gadjo-multi-select-widget" data-row-id="{{ widget.name }}" data-row-label="{% trans "Value" %}">
+  <div class="gadjo-multi-select-widget--fields" role="group" aria-labelledby="{{ widget.name }}_title">
+    {% for widget in widget.subwidgets %}
+      <div class="gadjo-multi-select-widget--field">
+        <label for="{{ widget.name }}_{{ forloop.counter }}" class="sr-only">{% trans "Value" %} {{ forloop.counter }}</label>
+        <div class="gadjo-multi-select-widget--select-button-container">
+          {% include widget.template_name %}
+          <button type="button" name="{{ widget.name }}$remove_element" class="gadjo-multi-select-widget--button-remove" title="{% trans "Remove" %}" aria-label="{% trans "Remove value" %} {{ forloop.counter }}"></button>
+        </div>
+      </div>
+    {% endfor %}
+  </div>
+
+  <button type="button" name="{{ widget.name }}$add_element" class="gadjo-multi-select-widget--button-add" title="{% trans "Add" %}" aria-label="{% trans "Add" %}"></button>
+</div>