"""
Copyright (C) 2015-2018 S[&]T, The Netherlands.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
"""

from __future__ import print_function

import cffi
import re
import sys

# Import the StringIO class that uses the default str type on each major version
# of Python.
#
# The StringIO.StringIO class is Python 2 specific and works with byte strings,
# i.e. instances of class str.
#
# The io.StringIO class exists in both Python 2 and Python 3, and always uses
# unicode strings, i.e. instances of class unicode on Python 2 and of class str
# on Python 3.
#
try:
    from cStringIO import StringIO
except ImportError:
    try:
        from StringIO import StringIO
    except ImportError:
        from io import StringIO

class Error(Exception):
    pass

class SyntaxError(Error):
    pass

def read_header_file(filename):
    cdefs = StringIO()
    active = False
    with open(filename) as header_file:
        for (line_no, line) in enumerate(header_file):
            if re.match(r"^\s*/\*\s*\*CFFI-ON\*\s*\*/\s*$", line) or re.match(r"^\s*//\s*\*CFFI-ON\*\s*$", line):
                if active:
                    raise SyntaxError("%s:%lu: CFFI-ON marker inside CFFI block" % (filename, line_no))
                active = True
                continue

            if re.match(r"^\s*/\*\s*\*CFFI-OFF\*\s*\*/\s*$", line) or re.match(r"^\s*//\s*\*CFFI-OFF\*\s*$", line):
                if not active:
                    raise SyntaxError("%s:%lu: CFFI-OFF marker outside CFFI block" % (filename, line_no))
                active = False
                continue

            # Remove LIBHARP_API prefix.
            line = re.sub("^\s*LIBHARP_API\s*", "", line)

            # Remove brackets from #define statements, since in ABI mode cffi only accepts #define followed by a numeric
            # constant.
            match_obj = re.match(r"^\s*#define\s+(\w+)\s+\(([^)]+)\)\s*$", line)
            if match_obj:
                name = match_obj.group(1)

                try:
                    value = int(match_obj.group(2))
                except ValueError:
                    try:
                        value = float(match_obj.group(2))
                    except ValueError:
                        # If the value cannot be parsed as an int or float, output the original line without
                        # modification.
                        pass
                    else:
                        line = "#define %s %f\n" % (name, value)
                else:
                    line = "#define %s %d\n" % (name, value)

            if active:
                cdefs.write(line)

    if active:
        raise SyntaxError("%s:%lu: unterminated CFFI block; CFFI-OFF marker missing" % (filename, line_no))

    return cdefs.getvalue()

def main(header_path, output_path):
    ffi = cffi.FFI()
    ffi.set_source("_harpc", None)
    ffi.cdef(read_header_file(header_path))
    ffi.emit_python_code(output_path)

if __name__ == "__main__":
    if len(sys.argv) != 3:
        print("usage: %s <path to harp.h.in> <output Python file>" % sys.argv[0])
        print("generate Python wrapper for the HARP C library using cffi (ABI level, out-of-line)")
        sys.exit(1)

    try:
        main(sys.argv[1], sys.argv[2])
    except Error as _error:
        print("ERROR: %s" % _error)
        sys.exit(1)
