Use graphviz to display the workflows admin pages header

wcs/admin/workflows.ptl

@@ -15,6 +15,9 @@
 # along with this program; if not, see <http://www.gnu.org/licenses/>.
 
 import time
+from StringIO import StringIO
+from subprocess import Popen, PIPE
+import textwrap
 
 from quixote import redirect, get_publisher
 from quixote.directory import Directory
@@ -30,6 +33,47 @@ from wcs.formdata import Evolution
 from wcs.admin.forms import ET, indent
 
 
+def graphviz(workflow, url_prefix='', select=None, svg=True,
+        include=False):
+    out = StringIO()
+    print >>out, 'digraph main {'
+    # print >>out, 'graph [ rankdir=LR ];'
+    print >>out, 'node [shape=box,style=filled];'
+    print >>out, 'edge [];'
+    for status in workflow.possible_status:
+        i = status.id
+        print >>out, 'status%s' % i,
+        print >>out, '[label="%s"' % status.name,
+        if select == str(i):
+            print >>out, ',color=salmon'
+        print >>out, ' URL="%sstatus/%s"];' % (url_prefix, i)
+
+    for status in workflow.possible_status:
+        i = status.id
+        for item in status.items:
+            if getattr(item, 'status', None):
+                next_id = item.status
+            else:
+                next_id = status.id
+            print >>out, 'status%s -> status%s' % (i, next_id)
+            url = 'status/%s/items/%s/' % (i, item.id)
+            label = textwrap.fill(item.render_as_line().replace('"', '\\"'), 20)
+            label = label.replace('\n', '\\n')
+            print >>out, '[label="%s"' % label,
+            if select == '%s-%s' % (i, item.id):
+                print >>out, ',color=salmon,fontcolor=salmon'
+            print >>out, ',URL="%s%s"]' % (url_prefix, url)
+    print >>out, '}'
+    out = out.getvalue()
+    if svg:
+        process = Popen(['dot', '-Tsvg', '/dev/stdin'], stdin=PIPE, stdout=PIPE)
+        out, err = process.communicate(out)
+        if include:
+            i = out.index('<svg')
+            out = out[i:]
+    return out
+
+
 class WorkflowUI:
     def __init__(self, workflow):
         self.workflow = workflow
@@ -162,6 +206,9 @@ class WorkflowStatusPage(Directory):
         '%s - %s</h2>' % (self.workflow.name, self.status.name)
         get_session().display_message()
 
+        htmltext(graphviz(self.workflow, url_prefix='../../', include=True,
+            select='%s' % self.status.id))
+
         '<div class="bo-block">'
         if not self.status.items:
             '<p>%s</p>' % _('There are not yet any items in this status.')
@@ -400,6 +447,8 @@ class WorkflowPage(Directory):
         '<div class="bo-block">'
         '<h3>%s</h3>' % _('Possible Status')
 
+        htmltext(graphviz(self.workflow, include=True))
+
         if not self.workflow.possible_status:
             '<p>%s</p>' % _('There are not yet any status defined in this workflow.')
         else: