#!/usr/bin/python3

# Update the module information used to generate related device IDs

import itertools
import json
import os.path
import subprocess
import sys


def iter_modules(base_dir):
    def onerror(e):
        raise e
    for root, dirs, files in \
        os.walk(os.path.join(base_dir, 'kernel'), onerror=onerror):
        for name in files:
            if name.endswith('.ko.xz'):
                yield name[:-6], os.path.join(root, name)
            elif name.endswith('.ko'):
                yield name[:-3], os.path.join(root, name)


def get_module_info(filename, attr_name):
    output = subprocess.check_output(['modinfo', '-F', attr_name, filename],
                                     text=True)
    if output == '':
        return []
    return output.rstrip('\n').split('\n')


class JSONEncoderWithSet(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, set):
            return sorted(o)
        return super().default(o)


def main(*kernel_ids):
    if not kernel_ids:
        kernel_dirs = '/lib/modules/' + os.uname().release
    else:
        kernel_dirs = [('/lib/modules/' + kernel_id
                        if '/' not in kernel_id
                        else kernel_id)
                       for kernel_id in kernel_ids]

    modinfo = {}
    for name, filename in itertools.chain.from_iterable(
            iter_modules(kernel_dir) for kernel_dir in kernel_dirs):
        # We only care about modules that might request firmware
        firmware = set(get_module_info(filename, 'firmware'))
        if not firmware:
            continue

        # We only care about aliases generated from device IDs, which
        # start with <type> ":"
        aliases = set(alias
                      for alias in get_module_info(filename, 'alias')
                      if ':' in alias)

        if name not in modinfo:
            modinfo[name] = {
                'alias': aliases,
                'firmware': firmware,
            }
        else:
            modinfo[name]['alias'] |= aliases
            modinfo[name]['firmware'] |= firmware

    with open('debian/modinfo.json', 'w') as f:
        json.dump(modinfo, f, indent=2, sort_keys=True, cls=JSONEncoderWithSet)


if __name__ == '__main__':
    main(*sys.argv[1:])