import sys
import os
import subprocess
import time
import argparse
import re
import ConsoleUtils

from random import randint as rand

prog_name = 'PDFBreak'
prog_descript = 'Breaks a pdf into it\'s component pages as separate files.'
prog_version = '0.1.0'
prog_date = '2017/09/27'
prog_auth = 'Chris Diesch <cdiesch@sequencelogic.net>'

USAGE = 'pdf-break [OPTIONS...] -i,--input IN_FILE -o,--out-dir OUT_DIR'

parser = argparse.ArgumentParser(prog=prog_name, description=prog_descript, usage=USAGE, add_help=False)

printer = ConsoleUtils.SLPrinter(prog_name)


_PAGE_NAME_FORMAT = 'page%05d.pdf'
_RUN_CLEAN = False
_REMOVE_PDF = False

_SPLIT_PAGES_CMD = 'pdftk %s burst output %s'
_CONVERT_PAGE_OUT_ARG = '-sOutputFile=%s'
_CONVERT_PAGE_TYPE_ARG = '-sDEVICE=jpeg'
_CONVERT_PAGE_DPI_ARG = '-r300'
_CONVERT_PAGES_CMD = 'gs -q -dBATCH -dNOPAUSE %s %s'

_VALID_FORMAT_REGEX = re.compile('^[^%]*%[0-9]*d.*$')


def _get_format(out_root):
    format = os.path.join(out_root, _PAGE_NAME_FORMAT)
    return format


def _split_pdf(pdf_file, out_root):
    out_format = '"%s"' % os.path.join(out_root, _PAGE_NAME_FORMAT)
    cmd = _SPLIT_PAGES_CMD % (pdf_file, out_format)

    print('Splitting pages with PDFTK')

    start_time = time.time()
    process = subprocess.Popen(cmd.split())
    process.wait()
    run_time = time.time() - start_time

    doc_data = os.path.join(out_root, 'doc_data.txt')
    with open(doc_data) as data_reader:
        lines = data_reader.readlines()

    page_cnt = 0
    for line in lines:
        if line.startswith('NumberOfPages:'):
            page_cnt = int(line[14:])
            break

    del lines

    if _RUN_CLEAN or _REMOVE_DATA:
        print('Deleting PDFTK data file: "%s"' % doc_data)
        try:
            os.remove(doc_data)
            print('Successfully deleted PDFTK data file')
        except BaseException as ex:
            print('Error: Unable to delete file "%s"' % doc_data)
            print(ex)

    pages_per_sec = float(page_cnt/run_time)
    print('Split %d pages in %.4f s (%.1f pg/s)' % (page_cnt, run_time, pages_per_sec))


def _convert_pages(out_root):
    files = [os.path.join(out_root, f) for f in os.listdir(out_root) if f.endswith('.pdf')]
    num_images = len(files)
    print('Converting %d PDF files to png images' % num_images)

    run_time = 0.0
    for file in files:
        out_img = file.replace('.pdf', '.png')
        cmd_args = '%s %s %s' % (_CONVERT_PAGE_TYPE_ARG, _CONVERT_PAGE_DPI_ARG, _CONVERT_PAGE_OUT_ARG % out_img)
        cmd = _CONVERT_PAGES_CMD % (cmd_args, file)

        print('Converting image "%s"' % file)
        start_time = time.time()
        process = subprocess.Popen(cmd.split())
        process.wait()
        run_time += (time.time() - start_time)
        # should the file be deleted
        if _RUN_CLEAN or _REMOVE_PDF:
            print('Deleting image "%s"' % file)
            try:
                os.remove(file)
            except BaseException as ex:
                print('Error: Unable to delete "%s"' % file)
                print(ex)
                printer.write_no_prefix('')
    convert_rate = float(run_time/num_images)

    if convert_rate < 1:
        convert_rate = 1/convert_rate
        print('Converted %d images in %.4f s (%.1f images/s)' % (num_images, run_time, convert_rate))
    else:
        print('Converted %d images in %.4f s (%.1f s/image)' % (num_images, run_time, convert_rate))


def main(input_pdf, out_root):
    _split_pdf(input_pdf, out_root)
    _convert_pages(out_root)


def _print_version():
    sys.stdout = printer.old_stdout
    print('')
    print(prog_name)
    print('Usage: %s' % USAGE)
    print('Version: %s' % prog_version)
    print('Date: %s' % prog_date)
    exit(0)


def _print_help():
    sys.stdout = printer.old_stdout
    print('')
    print(prog_name)
    print(prog_descript)
    print('Usage %s' % USAGE)
    print('')
    print('Options:')
    print('  Required:')
    print('     -i, --input IN_FILE          The input file to split.')
    print('     -o, --out-dir OUT_DIR        The parent folder to output the files to.')
    print('                                  By default the files are named page 1 = page-00001.pdf. This can be')
    print('                                  changed by using the -f, --format flag below.')
    print('')
    print('  Input/Output:')
    print('     -f, --format FORMAT          A printf-styled format string to name the files (default "page-%05d.pdf")')
    print('                                  Example: ')
    print('                                     page 1 = page_1.pdf would be --format "page_%d.pdf"')
    print('     -p, --clean-pdfs             Delete the individual PDF pages after converting to jpg.')
    print('     -d, --clean-data             Delete the "doc_data.txt" file produced by PDFTK form the output.')
    print('     -c, --clean-run              Delete all intermediate files (same as running with -p and -d).')
    print('')
    print('  Miscellaneous:')
    print('     -h, --help                   Prints the help message.')
    print('     -v, --version                Prints the version information.')
    print('')
    print('Version Info:')
    print('   Version: %s' % prog_version)
    print('   Date: %s' % prog_date)
    print('')
    print('Author: %s' % prog_auth)
    print('')
    exit(0)


def _make_args():
    # Required arguments
    required = parser.add_argument_group('Required')
    required.add_argument('-i', '--input', required=True)
    required.add_argument('-o', '--out-dir', required=True)
    # Output args
    output = parser.add_argument_group('Input/Output')
    output.add_argument('-f', '--format', default=_PAGE_NAME_FORMAT)
    output.add_argument('-c', '--clean-run', action='store_true')
    output.add_argument('-p', '--clean-pdfs', action='store_true')
    output.add_argument('-d', '--clean-data', action='store_true')
    # Miscellaneous arguments
    misc = parser.add_argument_group('Miscellaneous')
    misc.add_argument('-h', '--help', action=ConsoleUtils.CustomPrintAction, print_fn=_print_help)
    misc.add_argument('-v', '--version', action=ConsoleUtils.CustomPrintAction, print_fn=_print_version)


def _is_valid_format(format_str):
    # We should only have 1 format character
    num_format_chars = format_str.count('%')
    if num_format_chars != 1:
        return False
    # validate with regex
    result = _VALID_FORMAT_REGEX.match(format_str) is not None
    return result


def check_args():
    in_file = args.input
    out_dir = args.out_dir
    out_format = args.format

    fatal_error = False

    if not os.path.exists(in_file):
        print('Fatal Error: The given input file does not exist (%s)' % in_file)
        fatal_error = True

    if not os.path.exists(out_dir):
        print('Error: The provided output directory does not exist (%s)' % out_dir)
        print('Attempting to create directory at "%s"' % out_dir)
        try:
            os.makedirs(out_dir)
            print('OK: Created output directory successfully.')
        except BaseException as ex:
            print('Fatal Error: Could not create output directory at "%s"' % out_dir)
            print(ex)
            fatal_error = True

    if not _is_valid_format(out_format):
        print('Error: The provided format is not valid.')
        print('OK: Using default format (%s)' % _PAGE_NAME_FORMAT)
        args.format = _PAGE_NAME_FORMAT

    _show_args()

    if fatal_error:
        printer.write_no_prefix('')
        print('Exiting...')
        _print_help()
        exit(1)


def _show_args():
    in_file = args.input
    out_dir = args.out_dir

    ex_page_num = rand(1, 1000)

    print('Splitting pdf file: "%s"' % in_file)
    print('Saving split pages under: "%s"' % out_dir)
    print('Remove "doc_data.txt" output from PDFTK: %s' % _RUN_CLEAN)
    print('Saving split pages with name format: "%s"' % _PAGE_NAME_FORMAT)
    print('   Ex: page %d -> "%s"' % (ex_page_num, _PAGE_NAME_FORMAT % ex_page_num))
    printer.write_no_prefix('')


def _setup():
    print(ConsoleUtils.get_header(prog_name, prog_version, prog_date, prog_auth))
    _make_args()
    sys.stdout = printer


if __name__ == '__main__':
    _setup()
    # get the arguments
    args = parser.parse_args()
    # are they good?
    check_args()
    # default values
    _RUN_CLEAN = args.clean_run
    _REMOVE_PDF = args.clean_pdfs
    _REMOVE_DATA = args.clean_data
    _PAGE_NAME_FORMAT = args.format

    # non-default values
    input_file = args.input
    output_dir = args.out_dir

    # Run
    main(input_file, output_dir)