from __future__ import generators

import re
import time

_date_pat = re.compile('^(\d\d\d\d)-(\d\d)-(\d\d)\s+(.*)\s*$')

def _parse_header(line):
    if line[0].isspace(): return None
    match = _date_pat.match(line)
    if match:
        when = (int(match.group(1)),
                int(match.group(2)),
                int(match.group(3)),
                0,0,0, 0,0,0)
        who = match.group(4)
        return (when, who)
    parts = line.split(None, 5)
    if len(parts) == 6:
        try:
            timeval = ' '.join(parts[:5])
            when = time.strptime(timeval, '%a %b %d %H:%M:%S %Y')
            who = parts[5]
            return (when, who)
        except ValueError:
            pass
    return None

def parse(fp):
    '''parse a changelog in the standard format

    Yields tuples of the form (when, who, changes).'''
    when = None
    who = None
    changes = []

    for line in fp:
        header = _parse_header(line)
        if header:
            if when:
                yield (when, who, changes)
            when, who = header
            changes = []
        else:
            changes.append(line)
    if when:
        yield (when, who, changes)

def _escape(s):
    s = s.replace('&', '&')
    s = s.replace('<', '&lt;')
    s = s.replace('>', '&gt;')
    return s

def _break_into_paragraphs(lines):
    paragraphs = [[]]
    for line in lines:
        line = _escape(line.strip())
        if not line:
            if paragraphs[-1]:
                paragraphs.append([])
            continue
        if line[0] == '*': # bullets start new paragraphs
            if paragraphs[-1]:
                paragraphs.append([])
        paragraphs[-1].append(line)
    if not paragraphs[-1]: del paragraphs[-1]
    return paragraphs

def _splitword(s):
    parts = s.split(None, 1)
    parts.append('')
    return parts[0], parts[1]

email_pat = re.compile(r'(&lt;(.*@[-a-zA-Z0-9.]+)&gt;)')
bug_pat = re.compile(r'((?:bug\s+#?|#)(\d\d\d\d*))', re.I)

def _linkify(s, bugsroot=None):
    s = email_pat.sub(r'<a href="mailto:\2">\1</a>', s)
    if bugsroot:
        s = bug_pat.sub(r'<a href="%s\2">\1</a>' % bugsroot, s)
    return s

function_pat = re.compile(r'^(\s*\()([^\)]+)(\):.*)$')

def changes_to_html(changes, webcvsroot=None, bugsroot=None):
    ret = [ '<ul>\n' ]
    paragraphs = _break_into_paragraphs(changes)

    for para in paragraphs:
        if para[0][0] == '*':
            ret.append('<li>\n')
            # handle first line ...
            line = para[0][1:]
            while line:
                word, rest = _splitword(line)
                if word[0] == '(':
                    break
                line = rest
                trailer = ''
                if word[-1] in ',:':
                    trailer = word[-1]
                    word = word[:-1]
                if webcvsroot:
                    ret.append('<a href="%s%s">%s</a>'
                               % (webcvsroot, word, word))
                else:
                    ret.append('<b>%s</b>' % word)
                ret.append(trailer)
                ret.append(' ')
                if trailer == ':': break
            line = function_pat.sub(r'\1<i>\2</i>\3', line)
            ret.append(_linkify(line, bugsroot) + '\n')

            # print rest of lines
            for line in para[1:]:
                if function_pat.match(line):
                    ret.append('<br />\n')
                    line = function_pat.sub(r'\1<i>\2</i>\3', line)
                ret.append(_linkify(line, bugsroot) + '\n')
            ret.append('</li>\n')
        else:
            ret.append('<p>\n')
            for line in para:
                ret.append(_linkify(line, bugsroot) + '\n')
            ret.append('</p>\n')
    ret.append('</ul>\n')
    return ''.join(ret)