import os
import os.path
import re
import subprocess
import time

src_import = 'inherit (import ./src.nix fetchurl) name src;'

name_pattern = re.compile(r'name = "(?P<name>[^"]+)-(?P<version>[^"]+)";')
major_pattern = re.compile(r'major = "(?P<major>\d+.\d+)";')
minor_pattern = re.compile(r'minor = "(?P<minor>\d+)";')
url_pattern = re.compile(r'url = "?mirror://gnome/sources/[^/]+/[^/]+/[^";]+\.(?P<ext>(?:tar\.|t)(?:[gx]z|bz2))"?;')
hash_pattern = re.compile(r'sha256 = "(?P<hash>[^"]+?)";')
import_pattern = re.compile('\n( +){}'.format(re.escape(src_import)))

def gen_attrs(name, version, ext, hash, name_attr_exists):
    attr_path_fragment = '' if name_attr_exists else f' attrPath = "gnome3.{name}";'
    return ('\n' r'\1name = "' + name + r'-${version}";' '\n'
        r'\1version = "' + version + '";\n'
        '\n'
        r'\1src = fetchurl {' '\n'
        r'\1  url = "mirror://gnome/sources/' + name + r'/${gnome3.versionBranch version}/${name}.' + ext + '";\n'
        r'\1  sha256 = "' + hash + '";\n'
        r'\1};' '\n\n'
        r'\1passthru = {' '\n'
        r'\1  updateScript = gnome3.updateScript { packageName = "' + name + '";' + attr_path_fragment + ' };' '\n'
        r'\1};')


def inline_src(derivation):
    src = os.path.join(os.path.dirname(derivation), 'src.nix')

    with open(src) as f:
        src_data = f.read()
        name_match = name_pattern.search(src_data)
        major_match = major_pattern.search(src_data)
        minor_match = minor_pattern.search(src_data)
        url_match = url_pattern.search(src_data)
        hash_match = hash_pattern.search(src_data)

        # print(name_match, major_match, minor_match, url_match, hash_match)
        if not name_match or not url_match or not hash_match:
            print("Could not match src of derivation {}".format(derivation))
            return

    name = name_match.group('name')
    version = "{}.{}".format(major_match.group('major'), minor_match.group('minor')) if major_match and minor_match else name_match.group('version')
    ext = url_match.group('ext')
    hash = hash_match.group('hash')
    name_attr_exists = subprocess.call(['nix-instantiate', '-A', name], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL) == 0
    # print(name, version, ext, hash, name_attr_exists)

    with open(derivation) as f:
        drv_data = f.read()

    with open(derivation, 'w') as f:
        new_attrs = gen_attrs(name, version, ext, hash, name_attr_exists)
        new_drw = import_pattern.sub(new_attrs, drv_data)
        f.write(new_drw)

    time.sleep(0.02)
    subprocess.call(['git', 'rm', src])
    time.sleep(0.02)
    subprocess.call(['git', 'add', derivation])

if __name__ == '__main__':
    derivations = subprocess.run(['rg', '-lF', src_import, 'pkgs'], check=True, stdout=subprocess.PIPE).stdout.decode('utf-8').strip().split('\n')
    for derivation in derivations:
        inline_src(derivation)