import argparse
import random
import sys

from . import stl


def _get_parser(description):
    parser = argparse.ArgumentParser(description=description)
    parser.add_argument(
        "infile",
        nargs="?",
        type=argparse.FileType("rb"),
        default=sys.stdin,
        help="STL file to read",
    )
    parser.add_argument(
        "outfile",
        nargs="?",
        type=argparse.FileType("wb"),
        default=sys.stdout,
        help="STL file to write",
    )
    parser.add_argument("--name", nargs="?", help="Name of the mesh")
    parser.add_argument(
        "-n",
        "--use-file-normals",
        action="store_true",
        help="Read the normals from the file instead of recalculating them",
    )
    parser.add_argument(
        "-r",
        "--remove-empty-areas",
        action="store_true",
        help="Remove areas with 0 surface areas to prevent errors during "
        "normal calculation",
    )
    parser.add_argument(
        "-s", "--disable-speedups", action="store_true", help="Disable Cython speedups"
    )
    return parser


def _get_name(args):
    names = [
        args.name,
        getattr(args.outfile, "name", None),
        getattr(args.infile, "name", None),
        "numpy-stl-%06d" % random.randint(0, 1e6),
    ]

    for name in names:  # pragma: no branch
        if name and isinstance(name, str) and not name.startswith("<"):
            return name


def main():
    parser = _get_parser("Convert STL files from ascii to binary and back")
    parser.add_argument(
        "-a",
        "--ascii",
        action="store_true",
        help="Write ASCII file (default is binary)",
    )
    parser.add_argument(
        "-b", "--binary", action="store_true", help="Force binary file (for TTYs)"
    )

    args = parser.parse_args()
    name = _get_name(args)
    stl_file = stl.StlMesh(
        filename=name,
        fh=args.infile,
        calculate_normals=False,
        remove_empty_areas=args.remove_empty_areas,
        speedups=not args.disable_speedups,
    )

    if args.binary:
        mode = stl.BINARY
    elif args.ascii:
        mode = stl.ASCII
    else:
        mode = stl.AUTOMATIC

    stl_file.save(
        name, args.outfile, mode=mode, update_normals=not args.use_file_normals
    )


def to_ascii():
    parser = _get_parser("Convert STL files to ASCII (text) format")
    args = parser.parse_args()
    name = _get_name(args)
    stl_file = stl.StlMesh(
        filename=name,
        fh=args.infile,
        calculate_normals=False,
        remove_empty_areas=args.remove_empty_areas,
        speedups=not args.disable_speedups,
    )
    stl_file.save(
        name, args.outfile, mode=stl.ASCII, update_normals=not args.use_file_normals
    )


def to_binary():
    parser = _get_parser("Convert STL files to ASCII (text) format")
    args = parser.parse_args()
    name = _get_name(args)
    stl_file = stl.StlMesh(
        filename=name,
        fh=args.infile,
        calculate_normals=False,
        remove_empty_areas=args.remove_empty_areas,
        speedups=not args.disable_speedups,
    )
    stl_file.save(
        name, args.outfile, mode=stl.BINARY, update_normals=not args.use_file_normals
    )
