import json
import os
import argparse

program_name = 'LibraryMissing'
program_description = 'Finds all missing doctypes in a library given CLUX input'
parser = argparse.ArgumentParser(prog=program_name, description=program_description, add_help=False)

red_error = '\033[91mError:\033[0m'
yellow_warning = '\033[93mWARNING:\033[0m'
blue_okay = '\033[94mOK\033[0m'
program_header = format('\033[95m%s\033[0m\n'
                        '-----------------------' % program_name)
decision_message = '   Is this okay? (Y/N): '


def load_clux_results(file):
    doc_count = 0
    clux_results = {}
    clux_file = json.load(open(file))
    documents = clux_file["documents"]

    for document in documents:
        if not document["doctype"] == 'Unknown Document' and not document["doctype"] == 'Blank Page':
            clux_results[doc_count] = document["doctype"]
            doc_count += 1

    return clux_results


def search_library(library, doctypes):
    missing_doctypes = {}
    missing_doctype_count = 0
    # Loop through the doctypes...
    for i in range(len(doctypes)):
        # If it doesn't have a folder in the library, it is missing.
        if is_doctype_missing(library, doctypes[i]):
            missing_doctypes[missing_doctype_count] = doctypes[i]
            missing_doctype_count += 1

    return missing_doctypes


def is_doctype_missing(library, doctype):
    doctype_folder = os.path.join(library, doctype)
    # If the folder doesn't exist, the doctype is missing.
    if not os.path.exists(doctype_folder):
        return True
    # If the folder is empty, the doctype is missing.
    if not os.listdir(doctype_folder):
        return True
    # Otherwise the doctype is there! :D
    return False


def write_results(library, missing_doctypes, missing_file):
    with open(missing_file, 'w+') as doctypes_file:
        doctypes_file.write("There are %d missing doctypes in the library at %s\n" % (len(missing_doctypes), library))
        for i in range(len(missing_doctypes)):
            doctypes_file.write("%d) %s. \n" % (i+1, missing_doctypes[i]))

        doctypes_file.close()


def check_args(input, library, output):
    fatal_errors = False
    if os.path.exists(output):
        print('%s The file: %s already exists, it will be overwritten.' % (yellow_warning, output))
        yes_or_no(decision_message)

    # Check for fatal errors.
    if not os.path.exists(library):
        print('%s No library at %s' % (red_error, library))
        fatal_errors = True
    if not os.path.exists(input):
        print('%s No file at %s' % (red_error, input))
        fatal_errors = True

    if fatal_errors:
        parser.print_help()
        print('Exiting...')
        exit(0)


def yes_or_no(message):
    decision = input(message)
    if decision.lower() == 'y' or decision.lower() == 'yes':
        return
    elif decision.lower() == 'n' or decision.lower() == 'no':
        exit(0)
    else:
        yes_or_no('   Invalid input, enter Y(es) or N(o): ')


def main(library_folder, input_file, missing_file):
    clux_results = load_clux_results(input_file)
    missing_doctypes = search_library(library_folder, clux_results)
    write_results(library_folder, missing_doctypes, missing_file)


if __name__ == '__main__':
    required_args = parser.add_argument_group('Required')
    optional_args = parser.add_argument_group('Optional')
    required_args.add_argument('-i', '--input', required=True, help='The classification output from CLUX.')
    required_args.add_argument('-l', '--library', required=True,
                               help='The root folder of the library to check for missing doctypes in.')
    required_args.add_argument('-o', '--output', required=True,
                               help='The output file for the list of missing doctypes.')
    optional_args.add_argument('-h', '--help', action="help", help='Prints the help message.')

    args = parser.parse_args()
    clux_file = args.input
    lib_folder = args.library
    missing_file = args.output

    check_args(clux_file, lib_folder, missing_file)

    main(lib_folder, clux_file, missing_file)