import re
from slither.exceptions import SlitherException
from ..utils.patches import create_patch

def format(slither, patches, elements):
    for element in elements:
        if element['type'] != "function":
            # Skip variable elements
            continue
        target_contract = slither.get_contract_from_name(element['type_specific_fields']['parent']['name'])
        if target_contract:
            for function in target_contract.functions:
                if function.name == element['name']:
                    _patch(slither, patches,
                           element['source_mapping']['filename_absolute'],
                           element['source_mapping']['filename_relative'],
                           int(function.parameters_src.source_mapping['start']),
                           int(function.returns_src.source_mapping['start']))
                    break


def _patch(slither, patches, in_file, in_file_relative, modify_loc_start, modify_loc_end):
    in_file_str = slither.source_code[in_file].encode('utf-8')
    old_str_of_interest = in_file_str[modify_loc_start:modify_loc_end]
    m = re.search("(view|pure|constant)", old_str_of_interest.decode('utf-8'))
    if m:
        create_patch(patches,
                     "constant-function",
                     in_file_relative,
                     in_file,
                     modify_loc_start + m.span()[0],
                     modify_loc_start + m.span()[1],
                     m.groups(0)[0],
                     "")
    else:
        raise SlitherException("No view/pure/constant specifier exists. Regex failed to remove specifier!")