#!/usr/bin/env python

# SPDX-FileCopyrightText: Chris Pressey, the original author of this work, has dedicated it to the public domain.
# For more information, please refer to <https://unlicense.org/>
# SPDX-License-Identifier: Unlicense

"""A script to graft a bunch of directories into a staging area,
getting their contents from a bunch of Mercurial repos.  Uses .hg_archival.txt
to know when a grafted directory has not changed, and skips it then.
This process is controlled by a configuration file with a terrible syntax:

  destdir = repodir @ tag *"srcdir"

The *"srcdir" is optional.  If given, it is some subdir of the repodir, and
we graft in that dir instead of the root of the repo.

For example:

  docs = ../documents-repo @ tip
  images = ../media-repo @ rel_7_2 *"img/current site"

This script was used in the construction of Cat's Eye Technologies' website.
But it doesn't really belong in Chrysoberyl or transmat anymore.
Currently underemployed, it wanders amongst the riffraff in the Dipple.
But we may find a place for it in the future...

btw: No, the name of this script is not a Doctor Who reference.  While I am
a huge Doctor Who fan, my personal Doctor Who canon terminates abruptly
and absolutely as soon as Peripugilliam Brown opens her mouth and says
"OHH, DOC-TERRR!"  There is nothing beyond that.  The words "Colin Baker"
have no meaning for me.  The words "Sylvester Whatshisname" have no meaning
for me.  And so forth.  The name of this script is simply a phrase in French.

"""

import os
import re
import sys
from subprocess import check_call, Popen, PIPE


def do_it(command):
    print ">>> " + command
    check_call(command, shell=True)


def get_it(command):
    print ">>> " + command
    output = Popen(command, shell=True, stdout=PIPE).communicate()[0]
    print output
    return output


class Externals(object):
    def __init__(self, filename, user, host):
        CFG_PATTERN = re.compile(r"^\s*(.*?)\s*\=\s*(.*?)\s*\@\s*(.*?)\s*(\*\s*\"(.*?)\")?\s*$")
        self.externals = []
        self.user = user
        self.host = host
        for line in open(filename):
            match = CFG_PATTERN.match(line)
            if match is not None:
                dest = match.group(1)
                src = match.group(2)
                tag = match.group(3)
                subdir = match.group(5)
                self.externals.append({'src': src, 'dest': dest, 'tag': tag, 'subdir': subdir})

    def delete(self):
        staging_area = get_it('pwd').strip()
        for e in self.externals:
            dest = os.path.join(staging_area, e['dest'])
            do_it('rm -rf %s' % dest)

    def copy(self):
        staging_area = get_it('pwd').strip()
        for e in self.externals:
            # if source clone doesn't exist, try to clone it from host
            if not os.path.isdir(e['src']):
                name = e['dest'].split('/')[-1]
                do_it('hg clone https://%s@%s/%s/%s %s' %
                      (self.user, self.host, self.user, name, e['src']))
            dest = os.path.join(staging_area, e['dest'])
            arc_filename = os.path.join(dest, '.hg_archival.txt')
            tag = None
            f = None
            try:
                f = open(arc_filename, 'r')
            except IOError:
                pass
            if f:
                for line in f:
                    line = line.strip()
                    if line.startswith('tag: '):
                        tag = line[5:].strip()
                f.close()
            if tag == e['tag']:
                print "Tags match, not refreshing", e['src']
                continue
            do_it('rm -rf %s' % dest)
            os.chdir(e['src'])
            if e['subdir']:
                tmp = '/tmp/' + dest
                do_it('hg archive -r %s %s' % (e['tag'], tmp))
                do_it('mv "%s/%s" %s' % (tmp, e['subdir'], dest))
                do_it('cp %s/.hg_archival.txt %s' % (tmp, arc_filename))
            else:
                do_it('hg archive -r %s %s' % (e['tag'], dest))
        os.chdir(staging_area)


if __name__ == '__main__':
    e = Externals("externals.cfg", 'catseye', 'bitbucket.org')
    if sys.argv[1] == 'clean':
        e.delete()
    if sys.argv[1] == 'copy':
        e.copy()