# -*- coding: utf-8 -*-

# This file is a part of Netacka 3D.
#
# Copyright 2010
# Leszek Bartkowski, Mikołaj Dądela, Paweł Marczewski, Jan Szejko
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


import sys
import re

class Ignore(Exception):
    pass

def replace_symbol(pattern, replacement, text):
    return re.sub(r"\b" + pattern + r"\b", replacement, text)

def preprocess_line(line):
    global trans

    for f in trans: line = f(line)
    indent = re.match("^(\s*).*?$", line).group(1)
    words = tuple(line.split())
    if not words: return ""

    prettify = lambda ws: indent + " ".join(ws)

    # enabling/disablnig lines of code
    if r"//#." in line:
        if words[0].startswith("//#."):
            return prettify(words[1:] + (words[0],))
        if words[-1].startswith("//#."):
            return prettify((words[-1],) + words[:-1])
        raise Exception("tag should be placed on beginning or end of line")

    # commands
    if words[0].startswith(r"//#"):
        cmd = words[0][3:]
        if cmd == "autogenerated":
            raise Exception("this file is autogenerated, preprocessing it is dangerous!")
        if cmd == "ignore":
            raise Ignore
        if cmd == "replace":
            trans.append(lambda s: replace_symbol(words[1], words[2], s))
            return prettify(("// replaced:",) + words[1:])
        raise Exception("unknown command: "+words[0])
    return line

def preprocess(str):
    global trans; trans = []
    return "//#autogenerated\n\n" + "\n".join(map(preprocess_line, str.splitlines()))+"\n"

def preprocess_file(infile, outfile):
    try:
        infileH = open(infile, 'r')
        result = preprocess(infileH.read())
        outfileH = open(outfile, 'w')
        outfileH.write(result)
    except Ignore:
        pass

def main():
    if len(sys.argv) != 3:
        test()
        print("Usage: python preprocessor.py infile outfile")
        sys.exit()
    preprocess_file(sys.argv[1], sys.argv[2])


def test():
    assert(replace_symbol("GL","GL10","gl.GL2(GL10);") == 'gl.GL2(GL10);')
    assert(replace_symbol("GL","GL10","GL.foo()") == 'GL10.foo()')

    assert(preprocess("//#replace a b \n\t a(c);\n").endswith("\n\t b(c);\n"))

    assert(preprocess("\t //#.foo bar\n").endswith('\t bar //#.foo\n'))
    assert(preprocess("   bar //#.foo\n").endswith('   //#.foo bar\n'))
    try: preprocess("foo //#.bar baz\n"); assert(False)
    except: pass

    try: preprocess("//#autogenerated"); assert(False)
    except: pass


if __name__ == "__main__":
    main()