#!/usr/bin/env python3
import argparse
import difflib
import filecmp
import os
import subprocess
import shutil

TOOLS_DIR = os.path.abspath(os.path.dirname(__file__))
TMP_DIR = "/var/tmp"

def generate_files(source_file: str) -> None:
    # Copy the source CSV file to out temporary test directory.
    input_file_path = source_file
    output_file_path = os.path.join(TMP_DIR, "CSV_A")
    shutil.copyfile(input_file_path, output_file_path)

    # Generate the name map file in the temporary directory.
    input_file_path = output_file_path
    output_file_path = os.path.join(TMP_DIR, 'NAME_MAP_A')
    subprocess.check_call([os.path.join(TOOLS_DIR, 'setup', 'emoji', 'import_emoji_names_from_csv'),
                           '--input-file', input_file_path, '--output-file', output_file_path],
                          stdout=subprocess.DEVNULL)

    # Regenerate the CSV file from name map.
    input_file_path = output_file_path
    output_file_path = os.path.join(TMP_DIR, 'CSV_B')
    subprocess.check_call([os.path.join(TOOLS_DIR, 'setup', 'emoji', 'export_emoji_names_to_csv'),
                           '--input-file', input_file_path, '--output-file', output_file_path],
                          stdout=subprocess.DEVNULL)

    # Regenerate the name map file from the regenerated CSV file.
    input_file_path = output_file_path
    output_file_path = os.path.join(TMP_DIR, 'NAME_MAP_B')
    subprocess.check_call([os.path.join(TOOLS_DIR, 'setup', 'emoji', 'import_emoji_names_from_csv'),
                           '--input-file', input_file_path, '--output-file', output_file_path],
                          stdout=subprocess.DEVNULL)

def print_diff(path_file1, path_file2):
    # type: (str, str) -> None
    with open(path_file1) as file1:
        with open(path_file2) as file2:
            diff = difflib.unified_diff(
                file1.readlines(),
                file2.readlines(),
                fromfile=path_file1,
                tofile=path_file2,
            )
    for line in diff:
        print(line)

def compare_files(first_file: str, second_file: str) -> None:
    same = True
    same = same and filecmp.cmp(first_file, second_file, shallow=False)
    if not same:
        print_diff(first_file, second_file)
        raise Exception("Round trip conversion failed!!")

def check_files() -> None:
    # Compare the original and regenerated CSV files.
    first_file = os.path.join(TMP_DIR, 'CSV_A')
    second_file = os.path.join(TMP_DIR, 'CSV_B')
    compare_files(first_file, second_file)

    # Compare the name map files.
    first_file = os.path.join(TMP_DIR, 'NAME_MAP_A')
    second_file = os.path.join(TMP_DIR, 'NAME_MAP_B')
    compare_files(first_file, second_file)

def main() -> None:
    description = ("This tool is used test the emoji tooling that we use to import/export "
                   "naming related data. This works by doing a round-trip conversion of "
                   "and then verifying that no changes were made in the process.")
    parser = argparse.ArgumentParser(description=description)
    parser.add_argument(
        "--input-file", dest="input_file_path", type=str, metavar="<path>",
        default=os.path.join(TOOLS_DIR, "setup", "emoji", "emoji_names.csv"),
        help="Path to the CSV file to be used for round-trip conversion.")

    args = parser.parse_args()
    generate_files(args.input_file_path)
    check_files()

if __name__ == "__main__":
    main()