From 628b7947dcbf6e7ea598d4e8351425cd6027bec7 Mon Sep 17 00:00:00 2001
From: Matt Westcott <matt@west.co.tt>
Date: Wed, 11 Feb 2015 11:56:43 +0000
Subject: [PATCH] implement ImageChooserBlock

---
 wagtail/wagtailadmin/blocks.py   | 30 +-----------------------------
 wagtail/wagtailadmin/widgets.py  | 17 ++++++++++++-----
 wagtail/wagtailimages/blocks.py  | 20 ++++++++++++++++++++
 wagtail/wagtailimages/widgets.py |  3 +--
 4 files changed, 34 insertions(+), 36 deletions(-)
 create mode 100644 wagtail/wagtailimages/blocks.py

diff --git a/wagtail/wagtailadmin/blocks.py b/wagtail/wagtailadmin/blocks.py
index ec05e121b..1ab589833 100644
--- a/wagtail/wagtailadmin/blocks.py
+++ b/wagtail/wagtailadmin/blocks.py
@@ -385,36 +385,8 @@ class PageChooserBlock(ChooserBlock):
     def render_basic(self, value):
         if value:
             return format_html('<a href="{0}">{1}</a>', value.url, value.title)
-
-# =======
-# Chooser
-# =======
-
-class ChooserBlock(Block):
-    class Meta:
-        default = None
-
-    @property
-    def media(self):
-        return Media(js=['wagtailadmin/js/blocks/chooser.js'])
-
-    def js_initializer(self):
-        return "Chooser('%s')" % self.definition_prefix
-
-    def render_form(self, value, prefix='', error=None):
-        if self.label:
-            return format_html(
-                """<label>{label}</label> <input type="button" id="{prefix}-button" value="Choose a thing">""",
-                label=self.label, prefix=prefix
-            )
         else:
-            return format_html(
-                """<input type="button" id="{prefix}-button" value="Choose a thing">""",
-                prefix=prefix
-            )
-
-    def value_from_datadict(self, data, files, prefix):
-        return 123
+            return ''
 
 
 # ===========
diff --git a/wagtail/wagtailadmin/widgets.py b/wagtail/wagtailadmin/widgets.py
index 2f445cc98..5c283b26e 100644
--- a/wagtail/wagtailadmin/widgets.py
+++ b/wagtail/wagtailadmin/widgets.py
@@ -53,6 +53,17 @@ class AdminChooser(WidgetWithScript, widgets.Input):
         except model_class.DoesNotExist:
             return None
 
+    def get_instance_and_id(self, model_class, value):
+        if value is None:
+            return (None, None)
+        elif isinstance(value, model_class):
+            return (value, value.pk)
+        else:
+            try:
+                return (model_class.objects.get(pk=value), value)
+            except model_class.DoesNotExist:
+                return (None, None)
+
     def value_from_datadict(self, data, files, name):
         # treat the empty string as None
         result = super(AdminChooser, self).value_from_datadict(data, files, name)
@@ -83,11 +94,7 @@ class AdminPageChooser(AdminChooser):
 
     def render_html(self, name, value, attrs):
         model_class = self.target_content_type.model_class()
-        if isinstance(value, model_class):
-            instance = value
-            value = value.pk
-        else:
-            instance = self.get_instance(model_class, value)
+        instance, value = self.get_instance_and_id(model_class, value)
 
         original_field_html = super(AdminPageChooser, self).render_html(name, value, attrs)
 
diff --git a/wagtail/wagtailimages/blocks.py b/wagtail/wagtailimages/blocks.py
new file mode 100644
index 000000000..9e06ef28d
--- /dev/null
+++ b/wagtail/wagtailimages/blocks.py
@@ -0,0 +1,20 @@
+from django.utils.functional import cached_property
+
+from wagtail.wagtailadmin.blocks import ChooserBlock
+
+class ImageChooserBlock(ChooserBlock):
+    @cached_property
+    def target_model(self):
+        from wagtail.wagtailimages.models import get_image_model
+        return get_image_model()
+
+    @cached_property
+    def widget(self):
+        from wagtail.wagtailimages.widgets import AdminImageChooser
+        return AdminImageChooser
+
+    def render_basic(self, value):
+        if value:
+            return value.get_rendition('original').img_tag()
+        else:
+            return ''
diff --git a/wagtail/wagtailimages/widgets.py b/wagtail/wagtailimages/widgets.py
index e628ed4e9..e2e104d26 100644
--- a/wagtail/wagtailimages/widgets.py
+++ b/wagtail/wagtailimages/widgets.py
@@ -19,10 +19,9 @@ class AdminImageChooser(AdminChooser):
         self.image_model = get_image_model()
 
     def render_html(self, name, value, attrs):
+        instance, value = self.get_instance_and_id(self.image_model, value)
         original_field_html = super(AdminImageChooser, self).render_html(name, value, attrs)
 
-        instance = self.get_instance(self.image_model, value)
-
         return render_to_string("wagtailimages/widgets/image_chooser.html", {
             'widget': self,
             'original_field_html': original_field_html,