import subprocess
from collections import OrderedDict
from io import StringIO
from itertools import product


def _parse_categorical(line):
    # Categorical Lines consist of:
    #
    # <name><w*>{<values>}<w*>[<default>]<*w>#Comment
    # where:
    # <name> - name of parameter.
    # <values> - comma seperated list of values (i.e. a,b,c,d...,z)
    # <default> - default value enclosed in braces.
    # <w*> - zero or more whitespace characters
    # has_comment = False
    # comment = ""
    if '#' in line:
        comment_begins = line.find('#')
        line = line[:comment_begins]
        # comment = line[comment_begins:]
        # has_comment = True

    if line.count('{') != 1 or line.count('}') != 1:
        raise ValueError('Malformed parameter line %s' % line)

    first_bracket = line.find('{')
    second_bracket = line.find('}')
    domain_values = line[first_bracket + 1:second_bracket]
    cat_values = domain_values.split(',')
    if len(cat_values) < 1:
        raise ValueError('Expected at least one value in %s' % line)
    name = line[:first_bracket].strip()
    values = [value.strip() for value in cat_values]

    # Stripped the code for the default value since we don't need it here

    od = OrderedDict()
    od['name'] = name
    od['values'] = values
    return od


def parse_hyperparameter_string(param_string):
    params = OrderedDict()
    lines = param_string.split('\n')
    for line in lines:
        # Logic kind of copied from SMAC ACLIB version 2.06.01-dev,
        # but a little bit more restrictive
        # file: ca.ubc.cs.beta.aclib.configspace.ParamConfigurationSpace.java
        # line 497-546
        # type = ""
        if not line.strip():
            continue
        elif line.count('|') == 1:
            pass
            # print "WARNING: Conditionality is not parsed yet."
            # od = _parse_conditional(line)
        elif line.strip()[0] == '{':
            continue
        elif line.count('[') == 2:
            continue
        elif line.count('{') == 1 and line.count('}') == 1:
            od = _parse_categorical(line)
        else:
            raise ValueError('Cannot parse the following line %s' % line)
        params[od['name']] = od['values']
    return params


def construct_cli_call(cli_target, params):
    cli_call = StringIO()
    cli_call.write(cli_target)
    params = OrderedDict(sorted(params.items(), key=lambda t: t[0]))
    for param in params:
        cli_call.write(' -' + param + " \"'" + str(params[param]) + "'\"")
    return cli_call.getvalue()


def command_line_function(cli_target, params):
    call = construct_cli_call(cli_target, params)
    ret = subprocess.check_output(call, shell=True)
    return ret


def build_grid(hyperparameters):
    """Build a grid represented as a list of parameter dictionaries."""
    parameter_dicts = []
    for parameters in product(*hyperparameters.values()):
        parameter_tuples = zip(hyperparameters.keys(), parameters)
        parameter_dict = dict(parameter_tuples)
        parameter_dicts.append(parameter_dict)
    return parameter_dicts
