#!/usr/bin/env python

import os.path, re, sys, textwrap
sys.path.append('debian/lib/python')
from debian_linux.config import ConfigCoreHierarchy
from debian_linux.debian import Changelog

class Version(object):
    _rules = ur"^(\d+\.\d+\.\d+)\.(\d+)$"
    _re = re.compile(_rules)

    def __init__(self, version):
        self.complete = version
        match = self._re.match(version)
        if match is None:
            raise RuntimeError
        self.release = match.group(1)
        self.patch = int(match.group(2))

class GenPatch(object):
    def __init__(self, path, repo, version):
        self.config = ConfigCoreHierarchy(['debian/config'])
        self.package_version = Changelog()[0].version
        self.path = path
        self.repo = repo
        self.version = version

    def __call__(self):
        base = self.version.complete
        patch = base + '.patch'
        log = base + '.log'
        series = base + '.series'

        if self.version.patch == 1:
            tag_in = "v%s" % self.version.release
        else:
            tag_in = "v%s.%d" % (self.version.release, self.version.patch - 1)
        tag_out = "v%s" % self.version.complete
        print tag_in, tag_out

        backports = self.config[('backports',)]
        diff_filter = '-x Makefile'
        if self.version.release == self.package_version.upstream:
            diff_filter += ' ' + ' '.join("-x '%s'" % re.sub(r'/$', r'/*', path)
                                          for path in backports)
            git_paths = ''
        else:
            git_paths = ' '.join("'%s'" % path for path in backports
                                 if backports[path] == self.version.release)

        f = os.popen("cd %s; git diff %s %s -- %s | filterdiff -p 1 %s > %s" %
                     (self.repo, tag_in, tag_out, git_paths, diff_filter,
                      os.path.join(self.path, patch)))
        if f.close() is not None:
            raise RuntimeError

        f = os.popen("cd %s; git log --oneline --reverse %s..%s^ -- %s" %
                     (self.repo, tag_in, tag_out, git_paths))
        out = file(os.path.join(self.path, log), 'w')
        out.write("  * Add stable release %s:\n" % self.version.complete)
        for line in f:
            line = line.strip()
            if not line:
                continue
            hash, log = line.split(' ', 1)
            log = textwrap.wrap(log, 74)
            log = '\n      '.join(log)
            out.write("    - %s\n" % log)
        if f.close() is not None:
            raise RuntimeError

        out = file(os.path.join(self.path, series), 'w')
        out.write("+ bugfix/all/stable/%s\n" % patch)
        out.close()

if __name__ == '__main__':
    path = os.path.realpath(os.path.dirname(sys.argv[0]))
    repo = sys.argv[1]
    for i in sys.argv[2:]:
        GenPatch(path, repo, Version(i))()