"""Provides tools for parsing and writing to a csv file.
"""
from typing import List, Iterable, Tuple
import csv
import os

from fileutil import OMITTED_ADDITION, get_filename_addition, DELETED_ADDITION, FOUND_ADDITION
from outputresult import OutputResult


def records_to_csv(output_path: str, rows: Iterable[List[str]]):
    """Writes rows to a csv file at the specified path.

    Args:
        output_path (str): The path where the csv file will be written.
        rows (List[List[str]]): The rows to be written.  Each row of a 
                                list of strings will be written according 
                                to their index (i.e. column 3 will be index 2).
    """

    parent_dir, file = os.path.split(output_path)
    if not os.path.exists(parent_dir):
        os.makedirs(parent_dir)

    with open(output_path, 'w', encoding="utf-8-sig", newline='') as csvfile:
        writer = csv.writer(csvfile)
        for row in rows:
            writer.writerow(row)


def csv_to_records(input_path: str, header_row: bool) -> Tuple[List[List[str]], List[str]]:
    """Reads rows from a csv file at the specified path.

    Args:
        input_path (str): The path where the csv file will be read.
        header_row (bool): Whether or not there is a header row to be skipped.
    """

    with open(input_path, encoding='utf-8-sig') as csv_file:
        csv_reader = csv.reader(csv_file, delimiter=',')

        header = None
        results = []
        try:
            for row in csv_reader:
                if header_row:
                    header = row
                    header_row = False
                else:
                    results.append(row)
        except Exception as e:
            raise Exception("There was an error parsing csv {path}".format(path=input_path), e)

        return results, header


def write_results_to_csv(results: OutputResult, output_path: str):
    """
    Writes the result of processing to the output path as a csv file.  If omitted values are present, for output_path of
     /dir/file.csv, the omitted will be written to /dir/file-omitted.csv.

    Args:
        results: The results to be written.
        output_path: The output path.
    """

    records_to_csv(output_path, results.results)
    if results.omitted:
        records_to_csv(get_filename_addition(output_path, OMITTED_ADDITION), results.omitted)
    if results.deleted:
        records_to_csv(get_filename_addition(output_path, DELETED_ADDITION), results.deleted)
    if results.found:
        records_to_csv(get_filename_addition(output_path, FOUND_ADDITION), results.found)