import argparse
import decimal
import io
import json

import pytest

from . import any_date, relpath

import oxrlib.commands.historical as oxrhist

class FakeResponder:
    def __init__(self, response_path):
        self.response_path = response_path

    def _respond(self, *args, **kwargs):
        return open(self.response_path)

    def __getattr__(self, name):
        return self._respond

    def should_cache(self):
        return False


class FakeConfig:
    def __init__(self, responder, argvars=None):
        self.responder = responder
        self.args = argparse.Namespace()
        if argvars is not None:
            for key in argvars:
                setattr(self.args, key, argvars[key])

    def get_loaders(self):
        return self.responder


output = pytest.fixture(lambda: io.StringIO())

@pytest.fixture
def historical1_responder():
    return FakeResponder(relpath('historical1.json').as_posix())

def build_config(
        responder,
        date=None,
        amount=None,
        from_currency=None,
        to_currency=None,
        base='USD',
):
    return FakeConfig(responder, {
        'date': any_date() if date is None else date,
        'base': base,
        'amount': None if amount is None else decimal.Decimal(amount),
        'from_currency': from_currency,
        'to_currency': base if to_currency is None else to_currency,
    })

def lines_from_run(config, output):
    oxrhist.run(config, output, output)
    output.seek(0)
    return iter(output)

def test_rate_list(historical1_responder, output):
    config = build_config(historical1_responder)
    lines = lines_from_run(config, output)
    assert next(lines).startswith('1 AED = 0.27229')
    assert next(lines) == '1 USD = 3.67246 AED\n'
    assert next(lines).startswith('1 ALL = 0.0069189')
    assert next(lines) == '1 USD = 144.529793 ALL\n'
    assert next(lines).startswith('1 ANG = 0.55865')
    assert next(lines) == '1 USD = 1.79 ANG\n'

def test_one_rate(historical1_responder, output):
    config = build_config(historical1_responder, from_currency='ANG')
    lines = lines_from_run(config, output)
    assert next(lines).startswith('1 ANG = 0.55865')
    assert next(lines) == '1 USD = 1.79 ANG\n'
    assert next(lines, None) is None

def test_conversion(historical1_responder, output):
    config = build_config(historical1_responder, amount=10, from_currency='AED')
    lines = lines_from_run(config, output)
    # FIXME: Assertion probably changes after we deal with precision right.
    assert next(lines).startswith('10 AED = 2.72297')
    assert next(lines, None) is None

def test_back_conversion(historical1_responder, output):
    config = build_config(historical1_responder,
                          amount=2, from_currency='USD', to_currency='ALL')
    lines = lines_from_run(config, output)
    # FIXME: Assertion probably changes after we deal with precision right.
    assert next(lines) == '2 USD = 289.059586 ALL\n'
    assert next(lines, None) is None