"""Test validation of receipt metadata"""
# Copyright © 2020  Brett Smith
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

import decimal
import enum
import itertools
import random
import typing

import pytest

from . import testutil

from conservancy_beancount.plugin import meta_receipt

TEST_KEY = 'receipt'

class PostType(enum.IntFlag):
    NONE = 0
    CREDIT = 1
    DEBIT = 2
    BOTH = CREDIT | DEBIT


class AccountForTesting(typing.NamedTuple):
    name: str
    required_types: PostType
    fallback_meta: typing.Optional[str]

    def missing_message(self, include_fallback=True):
        if self.fallback_meta is None or not include_fallback:
            rest = ""
        else:
            rest = f"/{self.fallback_meta}"
        return f"{self.name} missing {TEST_KEY}{rest}"

    def wrong_type_message(self, wrong_value, key=TEST_KEY):
        expect_type = 'Decimal' if key == 'check-id' else 'str'
        return  "{} has wrong type of {}: expected {} but is a {}".format(
            self.name,
            key,
            expect_type,
            type(wrong_value).__name__,
        )


ACCOUNTS = [AccountForTesting._make(t) for t in [
    ('Assets:Bank:CheckCard', PostType.CREDIT, 'check'),
    ('Assets:Bank:CheckCard', PostType.DEBIT, 'check-id'),
    ('Assets:Cash', PostType.BOTH, None),
    ('Assets:Checking', PostType.CREDIT, 'check'),
    ('Assets:Checking', PostType.DEBIT, 'check-id'),
    ('Assets:Savings', PostType.BOTH, None),
    ('Liabilities:CreditCard', PostType.CREDIT, None),
    ('Liabilities:CreditCard', PostType.DEBIT, 'invoice'),
]]

ACCOUNTS_WITH_LINK_FALLBACK = [acct for acct in ACCOUNTS
                               if acct.fallback_meta and acct.fallback_meta != 'check-id']
ACCOUNTS_WITH_CHECK_ID_FALLBACK = [acct for acct in ACCOUNTS
                                   if acct.fallback_meta == 'check-id']
ACCOUNTS_WITHOUT_FALLBACKS = [acct for acct in ACCOUNTS if not acct.fallback_meta]
KNOWN_FALLBACKS = {acct.fallback_meta for acct in ACCOUNTS if acct.fallback_meta}

# These are mostly fill-in values.
# We don't need to run every test on every value for these, just enough to
# convince ourselves the hook never reports errors against these accounts.
# Making this a iterator rather than a sequence means testutil.combine_values
# doesn't require the decorated test to go over every value, which in turn
# trims unnecessary test time.
NOT_REQUIRED_ACCOUNTS = itertools.cycle([
    # Only paypal-id is required for PayPal transactions
    'Assets:PayPal',
    'Assets:Prepaid:Expenses',
    'Assets:Receivable:Accounts',
    'Equity:Retained',
    'Expenses:Other',
    'Income:Other',
    'Liabilities:Payable:Accounts',
    'Liabilities:UnearnedIncome:Donations',
])

CHECK_IDS = (decimal.Decimal(n) for n in itertools.count(1))
def BAD_CHECK_IDS():
    # Valid check-id values are positive integers
    yield decimal.Decimal(0)
    yield -next(CHECK_IDS)
    yield next(CHECK_IDS) * decimal.Decimal('1.1')
BAD_CHECK_IDS = BAD_CHECK_IDS()

def check(hook, test_acct, other_acct, expected, *,
          txn_meta={}, post_meta={}, check_type=PostType.BOTH, min_amt=0):
    check_type &= test_acct.required_types
    assert check_type, "tried to test a non-applicable account"
    if check_type == PostType.BOTH:
        check(hook, test_acct, other_acct, expected,
              txn_meta=txn_meta, post_meta=post_meta, check_type=PostType.CREDIT)
        check_type = PostType.DEBIT
    amount = decimal.Decimal('{:.02f}'.format(min_amt + random.random() * 100))
    if check_type == PostType.DEBIT:
        amount = -amount
    txn = testutil.Transaction(**txn_meta, postings=[
        (test_acct.name, amount, post_meta),
        (other_acct, -amount),
    ])
    actual = {error.message for error in hook.run(txn)}
    if expected is None:
        assert not actual
    elif isinstance(expected, str):
        assert expected in actual
    else:
        assert actual == expected

@pytest.fixture(scope='module')
def hook():
    config = testutil.TestConfig()
    return meta_receipt.MetaReceipt(config)

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS,
    NOT_REQUIRED_ACCOUNTS,
    testutil.LINK_METADATA_STRINGS,
))
def test_valid_receipt_on_post(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, None, post_meta={TEST_KEY: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS,
    NOT_REQUIRED_ACCOUNTS,
    testutil.NON_LINK_METADATA_STRINGS,
))
def test_invalid_receipt_on_post(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, {test_acct.missing_message()},
          post_meta={TEST_KEY: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS,
    NOT_REQUIRED_ACCOUNTS,
    testutil.NON_STRING_METADATA_VALUES,
))
def test_bad_type_receipt_on_post(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, test_acct.wrong_type_message(value),
          post_meta={TEST_KEY: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS,
    NOT_REQUIRED_ACCOUNTS,
    testutil.LINK_METADATA_STRINGS,
))
def test_valid_receipt_on_txn(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, None, txn_meta={TEST_KEY: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS,
    NOT_REQUIRED_ACCOUNTS,
    testutil.NON_LINK_METADATA_STRINGS,
))
def test_invalid_receipt_on_txn(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, {test_acct.missing_message()},
          txn_meta={TEST_KEY: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS,
    NOT_REQUIRED_ACCOUNTS,
    testutil.NON_STRING_METADATA_VALUES,
))
def test_bad_type_receipt_on_txn(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, test_acct.wrong_type_message(value),
          txn_meta={TEST_KEY: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_LINK_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    testutil.LINK_METADATA_STRINGS,
))
def test_valid_fallback_on_post(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, None,
          post_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_LINK_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    testutil.NON_LINK_METADATA_STRINGS,
))
def test_invalid_fallback_on_post(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, {test_acct.missing_message()},
          post_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_LINK_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    testutil.NON_STRING_METADATA_VALUES,
))
def test_bad_type_fallback_on_post(hook, test_acct, other_acct, value):
    expected = {
        test_acct.missing_message(),
        test_acct.wrong_type_message(value, test_acct.fallback_meta),
    }
    check(hook, test_acct, other_acct, expected,
          post_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_LINK_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    testutil.LINK_METADATA_STRINGS,
))
def test_valid_fallback_on_txn(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, None,
          txn_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_LINK_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    testutil.NON_LINK_METADATA_STRINGS,
))
def test_invalid_fallback_on_txn(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, {test_acct.missing_message()},
          txn_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_LINK_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    testutil.NON_STRING_METADATA_VALUES,
))
def test_bad_type_fallback_on_txn(hook, test_acct, other_acct, value):
    expected = {
        test_acct.missing_message(),
        test_acct.wrong_type_message(value, test_acct.fallback_meta),
    }
    check(hook, test_acct, other_acct, expected,
          txn_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_CHECK_ID_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    CHECK_IDS,
))
def test_valid_check_id_on_post(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, None,
          post_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_CHECK_ID_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    BAD_CHECK_IDS,
))
def test_invalid_check_id_on_post(hook, test_acct, other_acct, value):
    expected = {
        test_acct.missing_message(),
        f"{test_acct.name} has invalid {test_acct.fallback_meta}: {value}",
    }
    check(hook, test_acct, other_acct, expected,
          post_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_CHECK_ID_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    testutil.NON_STRING_METADATA_VALUES,
))
def test_bad_type_check_id_on_post(hook, test_acct, other_acct, value):
    if isinstance(value, decimal.Decimal):
        value = ''
    expected = {
        test_acct.missing_message(),
        test_acct.wrong_type_message(value, test_acct.fallback_meta),
    }
    check(hook, test_acct, other_acct, expected,
          post_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_CHECK_ID_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    CHECK_IDS,
))
def test_valid_check_id_on_txn(hook, test_acct, other_acct, value):
    check(hook, test_acct, other_acct, None,
          txn_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_CHECK_ID_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    BAD_CHECK_IDS,
))
def test_invalid_check_id_on_txn(hook, test_acct, other_acct, value):
    expected = {
        test_acct.missing_message(),
        f"{test_acct.name} has invalid {test_acct.fallback_meta}: {value}",
    }
    check(hook, test_acct, other_acct, expected,
          txn_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_CHECK_ID_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    testutil.NON_STRING_METADATA_VALUES,
))
def test_bad_type_check_id_on_txn(hook, test_acct, other_acct, value):
    if isinstance(value, decimal.Decimal):
        value = ''
    expected = {
        test_acct.missing_message(),
        test_acct.wrong_type_message(value, test_acct.fallback_meta),
    }
    check(hook, test_acct, other_acct, expected,
          txn_meta={test_acct.fallback_meta: value})

@pytest.mark.parametrize('test_acct,other_acct,key,value', testutil.combine_values(
    ACCOUNTS_WITHOUT_FALLBACKS,
    NOT_REQUIRED_ACCOUNTS,
    KNOWN_FALLBACKS,
    testutil.LINK_METADATA_STRINGS,
))
def test_fallback_not_accepted_on_other_accounts(hook, test_acct, other_acct, key, value):
    check(hook, test_acct, other_acct, {test_acct.missing_message()},
          post_meta={key: value})

@pytest.mark.parametrize('test_acct,other_acct,value', testutil.combine_values(
    ACCOUNTS_WITH_LINK_FALLBACK,
    NOT_REQUIRED_ACCOUNTS,
    testutil.LINK_METADATA_STRINGS,
))
def test_fallback_on_zero_amount_postings(hook, test_acct, other_acct, value):
    # Unfortunately it does happen that we get donations that go 100% to
    # banking fees, and our importer writes a zero-amount posting to the
    # Assets account.
    txn = testutil.Transaction(postings=[
        ('Income:Donations', '-.1'),
        ('Expenses:BankingFees', '.1'),
        (test_acct.name, 0, {test_acct.fallback_meta: value}),
    ])
    assert not list(hook.run(txn))

@pytest.mark.parametrize('test_acct,equity_acct', testutil.combine_values(
    ACCOUNTS,
    testutil.OPENING_EQUITY_ACCOUNTS,
))
def test_not_required_on_opening(hook, test_acct, equity_acct):
    check(hook, test_acct, equity_acct, None)

@pytest.mark.parametrize('test_acct,other_acct', testutil.combine_values(
    ACCOUNTS,
    NOT_REQUIRED_ACCOUNTS,
))
def test_not_required_on_flagged(hook, test_acct, other_acct):
    check(hook, test_acct, other_acct, None, txn_meta={'flag': '!'})