#!/usr/bin/python
# vi: ts=4 expandtab

# A crappy little script
# that changes bzr 'log' 
# into someting that rpm spec files can use (best effort)

import os
import re
import sys

from datetime import datetime
from datetime import date

import subprocess

E_TYPES = ['tags', 'revno', 'author', 'timestamp', 'committer']


def tiny_p(cmd):
    # Darn python 2.6 doesn't have check_output (argggg)
    sp = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                    stderr=subprocess.PIPE, stdin=None)
    (out, err) = sp.communicate()
    return (out, err)


def extract_entry(collecting):
    entry = {}
    for t in E_TYPES:
        look_for = "%s:" % (t)
        for v in collecting:
            if v.startswith(look_for):
                entry[t] = v[len(look_for):].strip()
                break
    i = -1
    # Messages seem to be the last element so suck 
    # those all up
    for a, v in enumerate(collecting):
        if v.startswith("message:"):
            i = a
            break
    if i != -1:
        msg_lines = collecting[i + 1:]
        entry['message'] = "\n".join(msg_lines)
    return entry


def clean_authors(authors):
    if not authors:
        return ''
    auth_cleaned = set()
    for a in authors:
        a = a.strip()
        if a:
            auth_cleaned.add(a)
    if not auth_cleaned:
        return ''
    uniq_authors = list(auth_cleaned)
    if len(uniq_authors) == 1:
        return authors[0]
    auths = "(%s)" % ", ".join(uniq_authors)
    return auths


def clean_revnos(revnos):
    novs = list()
    for r in revnos:
        r = r.strip()
        r = r.replace("[merge]", "")
        if r:
            novs.append(int(r))
    entries = list(novs)
    if not entries:
        return ''
    entries.sort()
    if len(entries) == 1:
        return "%s" % (entries[0])

    # Check if consecutive
    start = entries[0]
    consec = True
    for (i, v) in enumerate(entries):
        if v != start + i:
            consec = False
            break
    if consec:
        end = entries[-1]
        return "%s => %s" % (start, end)
    v = [str(b) for b in entries]
    return ", ".join(v)


def spacey(am):
    return " " * am


def justify(text, space_wanted):
    c_bef = len(text)
    t_c = len(text.lstrip())
    space_am = (c_bef - t_c)
    needed = (space_wanted - space_am)
    if needed < 0:
        return text
    return (" " * (needed) + text)


def clean_messages(messages):
    contents = []
    for msg in messages:
        # Split into sub-messages...
        # if we can
        lines = []
        pieces = msg.splitlines()
        if len(pieces) == 1:
            lines.append("%s- %s " %
                         (spacey(4), msg.strip()))
        else:
            n_lines = []
            n_lines.append(pieces[0].strip())
            for line in pieces[1:]:
                line = line.lstrip()
                if not line:
                    continue
                n_lines.append(justify(line, 6))
            lines.append("%s- %s" % (spacey(4), "\n".join(n_lines)))
        contents.extend(lines)
    return "\n".join(contents)


def build_changelog(history=-1):
    cmd = ['bzr', 'log', '--timezone=utc']
    (stdout, _stderr) = tiny_p(cmd)

    # Clean the format up
    entries = stdout.splitlines()
    all_entries = []
    collecting = []
    for e in entries:
        if e.startswith("---"):
            if collecting:
                a_entry = extract_entry(collecting)
                if a_entry:
                    all_entries.append(a_entry)
                collecting = []
        else:
            collecting.append(e)

    # Anything that we left behind??
    entry = extract_entry(collecting)
    if entry:
        all_entries.append(entry)

    if history > 0:
        take_entries = list(all_entries[0:history])
    else:
        take_entries = list(all_entries)

    # Merge those with same date
    date_entries = {}
    for e in take_entries:
        author = e.get('author')
        if not author:
            author = e.get('committer')
        if not author:
            continue
        timestamp = e.get('timestamp')
        if not timestamp:
            continue
        msg = e.get('message')
        if not msg:
            continue
        revno = e.get('revno')
        if not revno:
            continue
        # http://bugs.python.org/issue6641
        timestamp = timestamp.replace("+0000", '').strip()
        ds = datetime.strptime(timestamp, '%a %Y-%m-%d %H:%M:%S')
        ds = ds.date()
        if ds not in date_entries:
            entry = {}
            entry['messages'] = []
            entry['authors'] = []
            entry['revnos'] = []
            date_entries[ds] = entry
        entry = date_entries[ds]
        entry['messages'].append(msg)
        entry['authors'].append(author)
        entry['revnos'].append(revno)

    # It wants them in chronological order...
    dates = sorted(date_entries.keys())
    chglog = []
    for ds in reversed(dates):
        e = date_entries[ds]
        authors = clean_authors(e['authors'])
        revnos = clean_revnos(e['revnos'])
        top_line = "%s %s - [revison %s]" % (ds.strftime("%a %b %d %Y"),
                                   authors, revnos)
        chglog.append("* %s" % (top_line))
        chglog.append(clean_messages(e['messages']))
    return "\n".join(chglog)


if __name__ == '__main__':
    args = sys.argv[1:]
    history_am = -1
    if args:
        history_am = int(args[0])
    chglog = build_changelog(history_am)
    print chglog