#!/usr/bin/env python3

"""Extract an inline from a 3D seismic volume to a Numpy array.

This utility assumes the inline and crossline numbers are evenly spaced.
Each inline of the source data will be represented as a single row, and
each crossline as a single column in the resulting 2D array.

Usage: inline.py [-h] [--dtype DTYPE] [--null NULL]
                    segy-file npy-file inline-number

Positional arguments:
  segy-file      Path to an existing SEG Y file of 3D seismic data
  npy-file       Path to the Numpy array file to be created for the timeslice
  slice-index    Zero based index of the time slice to be extracted

Optional arguments:
  -h, --help     show this help message and exit
  --dtype DTYPE  Numpy data type. If not provided a dtype compatible with the
                 SEG Y data will be used.
  --null NULL    Sample value to use for missing or short traces.

Example:

  inline.py stack_final_int8.sgy slice_800.npy 800 --null=42.0 --dtype=f
"""

import argparse
import os
import sys
import traceback

import numpy as np

from numpy import s_

from segpy.reader import create_reader
from segpy_numpy.dtypes import make_dtype
from segpy_numpy.extract import extract_inline_3d


class DimensionalityError(Exception):
    pass


def extract_inline(segy_filename, out_filename, inline_number, null=None):
    """Extract a timeslice from a 3D SEG Y file to a Numpy NPY file.

    Args:
        segy_filename: Filename of a SEG Y file.

        out_filename: Filename of the NPY file.

        inline_index: The zero-based index (increasing with depth) of the slice to be extracted.

        null: Optional sample value to use for missing or short traces. Defaults to zero.
    """
    with open(segy_filename, 'rb') as segy_file:

        segy_reader = create_reader(segy_file)
        inline_array = extract_inline_3d(segy_reader, inline_number, null=null)
        return inline_array


def nullable_float(s):
    return None if not bool(s) else float(s)


def main(argv=None):
    parser = argparse.ArgumentParser()
    parser.add_argument("segy_file", metavar="segy-file",
                        help="Path to an existing SEG Y file of 3D seismic data")

    parser.add_argument("npy_file", metavar="npy-file",
                        help="Path to the Numpy array file to be created for the timeslice")

    parser.add_argument("inline_number", metavar="inline-number", type=int,
                        help="Zero based index of the inline to be extracted", )

    parser.add_argument("--null",  type=nullable_float, default="",
                        help="Sample value to use for missing or short traces.")

    if argv is None:
        argv = sys.argv[1:]

    args = parser.parse_args(argv)

    try:
        extract_inline(
            segy_filename=args.segy_file,
            out_filename=args.npy_file,
            inline_number=args.inline_number,
            null=args.null)
    except (FileNotFoundError, IsADirectoryError) as e:
        print(e, file=sys.stderr)
        return os.EX_NOINPUT
    except PermissionError as e:
        print(e, file=sys.stderr)
        return os.EX_NOPERM
    except Exception as e:
        traceback.print_exception(type(e), e, e.__traceback__, file=sys.stderr)
        return os.EX_SOFTWARE
    return os.EX_OK


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