--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/cm/utils/diff.py	Fri Feb 05 16:01:32 2010 +0100
@@ -0,0 +1,115 @@
+import difflib, string
+from django.utils.translation import ugettext as _
+
+def isatag(x): return x.startswith("<") and x.endswith(">")
+
+def text_diff(a, b):
+    res = []
+    a, b = createlist(a), createlist(b)
+    s = difflib.SequenceMatcher(isatag, a, b)
+    for e in s.get_opcodes():
+        if e[0] == "replace":
+            res.append('<del class="diff modified">'+''.join(a[e[1]:e[2]]) + '</del><ins class="diff modified">'+''.join(b[e[3]:e[4]])+"</ins>")
+        elif e[0] == "delete":
+            res.append('<del class="diff">'+ ''.join(a[e[1]:e[2]]) + "</del>")
+        elif e[0] == "insert":
+            res.append('<ins class="diff">'+''.join(b[e[3]:e[4]]) + "</ins>")
+        elif e[0] == "equal":
+            res.append(''.join(b[e[3]:e[4]]))
+        else: 
+            raise "error parsing %s" %(e[0])
+    return ''.join(res)
+
+COLORS = [
+'#FF0000',
+'#EE0000',
+'#DD0000',
+'#CC0000',
+'#BB0000',
+'#AA0000',
+'#990000',
+'#880000',
+'#770000',
+]
+
+from colorsys import hls_to_rgb, hsv_to_rgb
+
+def generatePastelColors(n):
+    s = .4
+    v = .99
+    return ['#'+''.join((hex(int(r*255))[2:],hex(int(g*255))[2:],hex(int(b*255))[2:])) for r,g,b in [hsv_to_rgb(h/200.,s,v) for h in range(1,100,100/n)]]
+    
+
+DEFAULT_COLOR = '#D9D9D9'
+def get_colors(authors, last_white = False):
+    """
+    returns a dict for authors's colors (with last one white if 'last_white')
+    """
+    authors = set(authors)
+    #new_colors = list(tuple(COLORS))
+    new_colors = generatePastelColors(len(set(authors)))
+    res = []
+    if None in authors or '' in authors:
+        res = [(_(u'unknown'),DEFAULT_COLOR) ]
+    res.extend([(author,new_colors.pop()) for author in authors if author])
+    #if authors[-1]:
+    #    res[authors[-1]] = '#FFFFFF'
+    return res
+    
+
+def text_history(versions, authors):
+    res = versions[0]
+    colors = get_colors(authors)
+    for ind in range(len(versions)-1):
+        author = authors[ind]
+        color = colors.get(author,DEFAULT_COLOR)
+        v_2 = versions[ind + 1]
+        res = text_diff_add(v_2, res, color)
+    return res,colors.items()
+
+from cm.utils.html import surrond_text_node
+ 
+def text_diff_add(a,b, color):
+    res = []
+    a, b = createlist(a), createlist(b)
+    s = difflib.SequenceMatcher(isatag, a, b)
+    for e in s.get_opcodes():
+        if e[0] == "replace":
+            html_chunk = ''.join(b[e[3]:e[4]])
+            new_html_chunk = surrond_text_node(html_chunk,'<span style="background: %s;">' %color,'</span>')
+            res.append(new_html_chunk)
+            #res.append('<font style="background: %s;" class="diff modified">' %color+''.join(b[e[3]:e[4]])+"</font>")
+        elif e[0] == "delete":
+            pass
+        elif e[0] == "insert":
+            html_chunk = ''.join(b[e[3]:e[4]])
+            new_html_chunk = surrond_text_node(html_chunk,'<span style="background: %s;">' %color,'</span>') 
+            res.append(new_html_chunk)
+            #res.append('<font style="background: %s;" class="diff">' %color+''.join(b[e[3]:e[4]]) + "</font>")
+        elif e[0] == "equal":
+            res.append(''.join(b[e[3]:e[4]]))
+        else: 
+            raise "error parsing %s" %(e[0])
+    return ''.join(res)
+
+def createlist(x, b=0):
+    mode = 'char'
+    cur = ''
+    out = []
+    for c in x:
+        if mode == 'tag':
+            if c == '>': 
+                if b: cur += ']'
+                else: cur += c
+                out.append(cur); cur = ''; mode = 'char'
+            else: cur += c
+        elif mode == 'char':
+            if c == '<': 
+                out.append(cur)
+                if b: cur = '['
+                else: cur = c
+                mode = 'tag'            
+            elif c in string.whitespace: out.append(cur+c); cur = ''
+            else: cur += c
+    out.append(cur)
+    return filter(lambda x: x is not '', out)