import importlib.resources
import inspect
import json
import re


def load_json(msg_type, package=None):
    if package is None:
        package = __package__ + '.resources'
    elif inspect.ismodule(package):
        package = package.__package__
    COMMENTS_REGEX = r"(?m)((?:^\s*//.*\n?)+)"
    # Raises FileNotFoundError if not found
    msg_json = importlib.resources.read_text(package, msg_type + '.json')
    data = json.loads(re.sub(COMMENTS_REGEX, '', msg_json))
    comments = re.findall(COMMENTS_REGEX, msg_json)
    if comments:
        data['license'] = comments[0]
        if len(comments) > 1:
            data['doc'] = comments[1]
    common_structs = {s['name']: s['fields'] for s in data.get('commonStructs', [])}
    if common_structs:
        _resolve_common_structs(data.get('fields', []), common_structs)
    return data


def _resolve_common_structs(fields, common_structs):
    for field in fields:
        field_type = field['type']
        struct_name = None
        if field_type.startswith('[]'):
            inner_type = field_type[2:]
            if inner_type and inner_type[0].isupper():
                struct_name = inner_type
        elif field_type and field_type[0].isupper():
            struct_name = field_type

        if struct_name and struct_name in common_structs and 'fields' not in field:
            field['fields'] = common_structs[struct_name]

        if 'fields' in field:
            _resolve_common_structs(field['fields'], common_structs)