import collections
import configparser
import contextlib
import datetime
import decimal
import io
import pathlib

import pytest
from import2ledger import errors
from import2ledger.hooks import ledger_entry

from . import DATA_DIR, normalize_whitespace

DATE = datetime.date(2015, 3, 14)

config = configparser.ConfigParser(comment_prefixes='#')
with pathlib.Path(DATA_DIR, 'templates.ini').open() as conffile:
    config.read_file(conffile)

def template_from(section_name, *args, **kwargs):
    return ledger_entry.Template(config[section_name]['template'], *args, **kwargs)

def template_vars(payee, amount, currency='USD', date=DATE, other_vars=None):
    call_vars = {
        'amount': decimal.Decimal(amount),
        'currency': currency,
        'date': date,
        'payee': payee,
        'ledger template': 'template',
    }
    if other_vars is None:
        return call_vars
    else:
        return collections.ChainMap(call_vars, other_vars)

def render_lines(render_vars, section_name, *args, **kwargs):
    tmpl = template_from(section_name, *args, **kwargs)
    rendered = tmpl.render(render_vars)
    return [normalize_whitespace(s) for s in rendered.splitlines()]

def assert_easy_render(tmpl, entity, amount, currency, expect_date, expect_amt):
    rendered = tmpl.render(template_vars(entity, amount, currency))
    lines = [normalize_whitespace(s) for s in rendered.splitlines()]
    assert lines == [
        "",
        "{} {}".format(expect_date, entity),
        "  Accrued:Accounts Receivable  " + expect_amt,
        "  Income:Donations  " + expect_amt.replace(amount, "-" + amount),
    ]
    assert not tmpl.is_empty()

def test_easy_template():
    tmpl = template_from('Simplest')
    assert_easy_render(tmpl, 'JJ', '5.99', 'CAD', '2015/03/14', '5.99 CAD')

def test_date_formatting():
    tmpl = template_from('Simplest', date_fmt='%Y-%m-%d')
    assert_easy_render(tmpl, 'KK', '6.99', 'CAD', '2015-03-14', '6.99 CAD')

def test_currency_formatting():
    tmpl = template_from('Simplest', signed_currencies=['USD'])
    assert_easy_render(tmpl, 'CC', '7.99', 'USD', '2015/03/14', '$7.99')

def test_empty_template():
    tmpl = ledger_entry.Template("\n \n")
    assert tmpl.render(template_vars('BB', '8.99')) == ''
    assert tmpl.is_empty()

def test_complex_template():
    render_vars = template_vars('TT', '125.50', other_vars={
        'entity': 'T-T',
        'program': 'Spectrum Defense',
        'txid': 'ABCDEF',
    })
    lines = render_lines(
        render_vars, 'Complex',
        date_fmt='%Y-%m-%d',
        signed_currencies=['USD'],
    )
    assert lines == [
        "",
        "2015-03-14 TT",
        "  ;Tag: Value",
        "  ;TransactionID: ABCDEF",
        "  Accrued:Accounts Receivable  $125.50",
        "  ;Entity: Supplier",
        "  Income:Donations:Spectrum Defense  $-119.85",
        "  ;Program: Spectrum Defense",
        "  ;Entity: T-T",
        "  Income:Donations:General  $-5.65",
        "  ;Entity: T-T",
    ]

def test_balancing():
    lines = render_lines(template_vars('FF', '1.01'), 'FiftyFifty')
    assert lines == [
        "",
        "2015/03/14 FF",
        "  Accrued:Accounts Receivable  1.01 USD",
        "  Income:Donations  -0.50 USD",
        "  Income:Sales  -0.51 USD",
    ]

def test_multivalue():
    render_vars = template_vars('DD', '150.00', other_vars={
        'tax': decimal.Decimal('12.50'),
    })
    lines = render_lines(render_vars, 'Multivalue')
    assert lines == [
        "",
        "2015/03/14 DD",
        "  Expenses:Taxes  12.50 USD",
        "  ;TaxAuthority: IRS",
        "  Accrued:Accounts Receivable  137.50 USD",
        "  Income:RBI  -15.00 USD",
        "  Income:Donations  -135.00 USD",
    ]

def test_zeroed_account_skipped():
    render_vars = template_vars('GG', '110.00', other_vars={
        'tax': decimal.Decimal(0),
    })
    lines = render_lines(render_vars, 'Multivalue')
    assert lines == [
        "",
        "2015/03/14 GG",
        "  Accrued:Accounts Receivable  110.00 USD",
        "  Income:RBI  -11.00 USD",
        "  Income:Donations  -99.00 USD",
    ]

def test_zeroed_account_last():
    render_vars = template_vars('JJ', '90.00', other_vars={
        'item_sales': decimal.Decimal(0),
    })
    lines = render_lines(render_vars, 'Multisplit')
    assert lines == [
        "",
        "2015/03/14 JJ",
        "  Assets:Cash  90.00 USD",
        "  Income:Sales  -90.00 USD",
        "  ; :NonItem:",
    ]

def test_multiple_postings_same_account():
    render_vars = template_vars('LL', '80.00', other_vars={
        'item_sales': decimal.Decimal(30),
    })
    lines = render_lines(render_vars, 'Multisplit')
    assert lines == [
        "",
        "2015/03/14 LL",
        "  Assets:Cash  80.00 USD",
        "  Income:Sales  -50.00 USD",
        "  ; :NonItem:",
        "  Income:Sales  -30.00 USD",
        "  ; :Item:",
    ]

def test_custom_payee_line():
    render_vars = template_vars('ZZ', '10.00', other_vars={
        'custom_date': datetime.date(2014, 2, 13),
    })
    lines = render_lines(render_vars, 'Custom Payee')
    assert lines == [
        "",
        "2014/02/13  ZZ - Custom",
        "  Accrued:Accounts Receivable  10.00 USD",
        "  Income:Donations  -10.00 USD",
    ]

def test_line1_not_custom_payee():
    render_vars = template_vars('VV', '15.00', other_vars={
        'custom_date': datetime.date(2014, 2, 12),
    })
    lines = render_lines(render_vars, 'Simplest')
    assert lines == [
        "",
        "2015/03/14 VV",
        "  Accrued:Accounts Receivable  15.00 USD",
        "  Income:Donations  -15.00 USD",
    ]

@pytest.mark.parametrize('amount,expect_fee', [
    (40, 3),
    (80, 6),
])
def test_conditional(amount, expect_fee):
    expect_cash = amount - expect_fee
    amount_s = '{:.02f}'.format(amount)
    render_vars = template_vars('Buyer', amount_s)
    lines = render_lines(render_vars, 'Conditional')
    assert lines == [
        "",
        "2015/03/14 Buyer",
        "  Assets:Cash  {:.02f} USD".format(expect_cash),
        "  Expenses:Banking Fees  {:.02f} USD".format(expect_fee),
        "  Income:Sales  -{} USD".format(amount_s),
    ]

def test_string_conditionals():
    render_vars = template_vars('MM', '6', other_vars={
        'false': '',
        'true': 'true',
    })
    lines = render_lines(render_vars, 'StringConditional')
    assert lines == [
        "",
        "2015/03/14 MM",
        "  Income:Sales  -1.00 USD",
        "  Income:Sales  -2.00 USD",
        "  Income:Sales  -3.00 USD",
        "  Assets:Cash  6.00 USD",
    ]

def test_self_balanced():
    # The amount needs to be different than what's in the template.
    render_vars = template_vars('NN', '0')
    lines = render_lines(render_vars, 'SelfBalanced')
    assert lines == [
        "",
        "2015/03/14 NN",
        "  Income:Sales  -5.00 USD",
        "  Assets:Cash  5.00 USD",
    ]

@pytest.mark.parametrize('amount_expr', [
    '',
    'name',
    '-',
    '()',
    '+()',
    '{}',
    '{{}}',
    '{()}',
    '{name',
    'name}',
    '{42}',
    '(5).real',
    '{amount.real}',
    '{amount.is_nan()}',
    '{Decimal}',
    '{FOO}',
])
def test_bad_amount_expression(amount_expr):
    with pytest.raises(errors.UserInputError):
        ledger_entry.Template(" Income  " + amount_expr)

class Config:
    def __init__(self, use_section):
        self.section_name = use_section
        self.stdout = io.StringIO()

    @contextlib.contextmanager
    def open_output_file(self):
        yield self.stdout

    def get_section(self, name=None):
        return config[self.section_name]


def run_hook(entry_data, config_section):
    hook_config = Config(config_section)
    hook = ledger_entry.LedgerEntryHook(hook_config)
    assert hook.run(entry_data) is None
    stdout = hook_config.stdout.getvalue()
    return normalize_whitespace(stdout).splitlines()

def test_hook_renders_template():
    entry_data = template_vars('BB', '0.99')
    lines = run_hook(entry_data, 'Simplest')
    assert lines == [
        "",
        "2015-03-14 BB",
        "  Accrued:Accounts Receivable  $0.99",
        "  Income:Donations  -$0.99",
    ]

def test_hook_handles_empty_template():
    entry_data = template_vars('CC', 1)
    assert not run_hook(entry_data, 'Empty')

def test_hook_handles_template_undefined():
    entry_data = template_vars('DD', 1)
    assert not run_hook(entry_data, 'Nonexistent')

def test_string_value_is_user_error():
    entry_data = template_vars('EE', 1)
    with pytest.raises(errors.UserInputConfigurationError):
        run_hook(entry_data, 'NondecimalWord')

def test_string_variable_is_user_error():
    entry_data = template_vars('FF', 1)
    with pytest.raises(errors.UserInputConfigurationError):
        run_hook(entry_data, 'NondecimalVariable')