#!/usr/bin/env python3

"""
compares two pdf files.
"""
import io
import logging
import sys
from typing import Any, Iterable, List, Optional

import pdfminer.settings
from pdfminer import high_level, layout

pdfminer.settings.STRICT = False


logging.basicConfig()


def compare(file1: str, file2: str, **kwargs: Any) -> Iterable[str]:
    # If any LAParams group arguments were passed,
    # create an LAParams object and
    # populate with given args. Otherwise, set it to None.
    if kwargs.get('laparams', None) is None:
        laparams = layout.LAParams()
        for param in ("all_texts", "detect_vertical", "word_margin",
                      "char_margin", "line_margin", "boxes_flow"):
            paramv = kwargs.get(param, None)
            if paramv is not None:
                setattr(laparams, param, paramv)
        kwargs['laparams'] = laparams

    s1 = io.StringIO()
    with open(file1, "rb") as fp:
        high_level.extract_text_to_fp(fp, s1, **kwargs)

    s2 = io.StringIO()
    with open(file2, "rb") as fp:
        high_level.extract_text_to_fp(fp, s2, **kwargs)

    import difflib
    s1.seek(0)
    s2.seek(0)
    s1_lines, s2_lines = s1.readlines(), s2.readlines()

    import os.path
    try:
        extension = os.path.splitext(kwargs['outfile'])[1][1:4]
        if extension.lower() == 'htm':
            return difflib.HtmlDiff().make_file(s1_lines, s2_lines)
    except KeyError:
        pass
    return difflib.unified_diff(s1_lines, s2_lines, n=kwargs['context_lines'])


# main
def main(args: Optional[List[str]] = None) -> int:
    import argparse
    P = argparse.ArgumentParser(description=__doc__)
    P.add_argument("file1", type=str, default=None, help="File 1 to compare.")
    P.add_argument("file2", type=str, default=None, help="File 2 to compare.")
    P.add_argument("-o", "--outfile", type=str, default="-",
                   help="Output file(default/'-' is stdout) if .htm or .html,"
                        " create an HTML table (or a complete HTML file "
                        "containing the table) showing a side by side, "
                        "line by line comparison of text with inter-line and "
                        "intra-line change  highlights. The table can be "
                        "generated in either full or "
                        "contextual difference mode.")
    P.add_argument("-N", "--context-lines", default=3, type=int,
                   help="context lines shown")
    P.add_argument("-d", "--debug", default=False, action="store_true",
                   help="Debug output.")

    # params for pdf2txt
    P.add_argument("-p", "--pagenos", type=str,
                   help="Comma-separated list of page numbers to parse. "
                        "Included for legacy applications, "
                        "use --page-numbers for more "
                        "idiomatic argument entry.")
    P.add_argument("--page-numbers", type=int, default=None, nargs="+",
                   help="Alternative to --pagenos with space-separated "
                        "numbers; supercedes --pagenos where it is used.")
    P.add_argument("-m", "--maxpages", type=int, default=0,
                   help="Maximum pages to parse")
    P.add_argument("-P", "--password", type=str, default="",
                   help="Decryption password for both PDFs")
    P.add_argument("-t", "--output_type", type=str, default="text",
                   help="pdf2txt type: text|html|xml|tag (default is text)")
    P.add_argument("-c", "--codec", type=str, default="utf-8",
                   help="Text encoding")
    P.add_argument("-s", "--scale", type=float, default=1.0, help="Scale")
    P.add_argument("-A", "--all-texts", default=None, action="store_true",
                   help="LAParams all texts")
    P.add_argument("-V", "--detect-vertical", default=None,
                   action="store_true", help="LAParams detect vertical")
    P.add_argument("-W", "--word-margin", type=float, default=None,
                   help="LAParams word margin")
    P.add_argument("-M", "--char-margin", type=float, default=None,
                   help="LAParams char margin")
    P.add_argument("-L", "--line-margin", type=float, default=None,
                   help="LAParams line margin")
    P.add_argument("-F", "--boxes-flow", type=float, default=None,
                   help="LAParams boxes flow")
    P.add_argument("-Y", "--layoutmode", default="normal", type=str,
                   help="HTML Layout Mode")
    P.add_argument("-n", "--no-laparams", default=False,
                   action="store_true", help="Pass None as LAParams")
    P.add_argument("-R", "--rotation", default=0, type=int,
                   help="Rotation")
    P.add_argument("-O", "--output-dir", default=None,
                   help="Output directory for images")
    P.add_argument("-C", "--disable-caching", default=False,
                   action="store_true", help="Disable caching")
    P.add_argument("-S", "--strip-control", default=False,
                   action="store_true", help="Strip control in XML mode")

    A = P.parse_args(args=args)

    if A.debug:
        logging.getLogger().setLevel(logging.DEBUG)

    if A.page_numbers:
        A.page_numbers = {x-1 for x in A.page_numbers}
    if A.pagenos:
        A.page_numbers = {int(x)-1 for x in A.pagenos.split(",")}

    if A.output_type == "text" and A.outfile != "-":
        for override, alttype in ((".htm",  "html"),
                                  (".html", "html"),
                                  (".xml",  "xml"),
                                  (".tag",  "tag")):
            if A.outfile.endswith(override):
                A.output_type = alttype

    if A.outfile == "-":
        outfp = sys.stdout
    else:
        outfp = open(A.outfile, "w", encoding='utf-8')
    outfp.writelines(compare(**vars(A)))
    outfp.close()
    return 0


if __name__ == '__main__':
    sys.exit(main())
