import csv
import datetime
import decimal
import io
import importlib
import itertools
import pathlib
import shutil
import re

import pytest
import yaml
from import2ledger import importers, strparse

from . import DATA_DIR

class TestImporters:
    with pathlib.Path(DATA_DIR, 'imports.yml').open() as yaml_file:
        test_data = yaml.load(yaml_file)
    for test in test_data:
        test['source'] = DATA_DIR / test['source']

        module_name, class_name = test['importer'].rsplit('.', 1)
        module = importlib.import_module('.' + module_name, 'import2ledger.importers')
        test['importer'] = getattr(module, class_name)

    @pytest.mark.parametrize('source_path,importer', [
        (t['source'], t['importer']) for t in test_data
    ])
    def test_can_import(self, source_path, importer):
        with source_path.open() as source_file:
            assert importer.can_import(source_file)

    @pytest.mark.parametrize('source_path,importer,header_rows,header_cols', [
        (t['source'], t['importer'], t['header_rows'], t['header_cols'])
        for t in test_data if t.get('header_rows')
    ])
    def test_can_import_squared_csv(self, source_path, importer, header_rows, header_cols):
        # Sometimes when we munge spreadsheets by hand (e.g., to filter by
        # project) tools like LibreOffice Calc write a "squared" spreadsheet,
        # where every row has the same length.  This test ensures the results
        # are still recognized for import.
        with io.StringIO() as squared_file:
            csv_writer = csv.writer(squared_file)
            with source_path.open() as source_file:
                for row in itertools.islice(csv.reader(source_file), header_rows):
                    padding = [None] * (header_cols - len(row))
                    csv_writer.writerow(row + padding)
                shutil.copyfileobj(source_file, squared_file)
            squared_file.seek(0)
            assert importer.can_import(squared_file)

    @pytest.mark.parametrize('source_path,import_class,expect_results', [
        (t['source'], t['importer'], t['expect']) for t in test_data
    ])
    def test_import(self, source_path, import_class, expect_results):
        with source_path.open() as source_file:
            importer = import_class(source_file)
            for actual, expected in itertools.zip_longest(importer, expect_results):
                actual['amount'] = strparse.currency_decimal(actual['amount'])
                assert actual == expected

    def test_loader(self):
        all_importers = list(importers.load_all())
        for test in self.test_data:
            assert test['importer'] in all_importers