#!/usr/bin/env python3

#  expand-terrain-macros.py - Expand "meta-macros" for terrain WML
#
#  Copyright (C) 2008 - 2009 by Moritz Goebelbecker
#  Part of the Battle for Wesnoth Project https://www.wesnoth.org
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License version 2
#  or at your option any later version.
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY.
#
#  See the COPYING file for more details.



#  Meta-Macro syntax:
#  #meta-macro BASENAME [{NORMAL_PARAM, OPTIONAL_PARAM} [...]]
#
#  NORMAL_PARAM: Macro parameter that will be passed unmodified to the base
#  macro
#  OPTIONAL_PARAM: Macro parameter that will sometimes be passed to the base
#  macro and sometimes be replaced with a default value. The script will
#  create one macro for each possible combination of optional parameters
#
#  Syntax:         ABBREV=NAME=DEFAULT
#    ABBREV:       One letter that is appended to macros taking that argument
#    NAME:         Name of the parameter that is used when it's passed to the
#                  base macro
#    ABBREV:       Default value that is used when the parameter is not passed
#                  to the base macro
#
#
#  !!! ONLY USE THIS IF YOU KNOW WHAT YOU ARE DOING !!!

import sys
import argparse

parser = argparse.ArgumentParser(description="",
epilog="If no options are specified, only the expanded sections will be printed to stdout")
group = parser.add_mutually_exclusive_group()
group.add_argument("-i", "--insert", action="store_true",
help="Insert the expanded sections into the input file(s) immediately after their macro definitions.")
group.add_argument("-a", "--append", action="store_true",
help="Append the expanded sections to the input file(s).")
parser.add_argument("-r", "--replace", action="store_true",
help="Replace the input file(s) with the resulting output. Previously generated expansions will be removed. Implies -i if nothing else is specified.")
parser.add_argument("filenames", nargs="+")
args = parser.parse_args()

insert = args.insert
append = args.append
replace = args.replace

if replace and not append:
    insert = True

for filename in args.filenames:
    with open(filename) as f:
        content = f.readlines()

    changed = False
    output = []
    appended = []

    autogenerated = False
    for line in content:
        if line.strip() == "#The following code is autogenerated\
 by expand-terrain-macros.py":
            autogenerated = True

        if (insert or append)  and not autogenerated:
            output.append(line.rstrip("\n"))

        if line.strip() == "#end of generated code":
            autogenerated = False

        if line.startswith('#meta-macro'):
            elems = line[12:].strip().split()
            basename = elems[0]
            params = []
            optional_params = []

            for param in elems[1:]:
                split_param = param.split('=')
                if len(split_param) == 3:
                    optional_params.append(split_param[0])
                elif len(split_param) != 1:
                    print("Error in line:\n" + line)
                    sys.exit(1)

                params.append(split_param)

            base_macro_suffix = "_" + "".join(optional_params)

            result = []
            result.append("#The following code is autogenerated\
 by expand-terrain-macros.py")
            if append:
                result.append("#generated from: " + line.strip())
            result.append("#Please do not modify")

            for i in range(2**len(optional_params) - 2, -1, -1):
                enabled_map = {param: i & (1<<index) != 0 for index, param in enumerate(optional_params)}

                suffix = ""
                params_external = []
                params_internal = []

                for param in params:
                    #normal parameter
                    if len(param) == 1:
                        params_external.append(param[0])
                        params_internal.append('({'+param[0]+'})')
                    else:
                        #enabled optional parameter
                        if enabled_map[param[0]]:
                            suffix += param[0]
                            params_external.append(param[1])
                            params_internal.append('({'+param[1]+'})')
                        else:
                            params_internal.append(param[2])

                if len(suffix) > 0:
                    suffix = "_"+suffix

                result.append("#define " + basename + suffix + " " + " ".join(params_external))
                result.append("    {" + basename + base_macro_suffix + " "  + " ".join(params_internal) + "}")
                result.append("#enddef")

            result.append("#end of generated code")
            changed = True

            if insert:
                output += result
            elif append:
                appended += result
            else:
                for r in result:
                    print(r)

    if (insert or append) and not replace:
        for line in output:
            print(line)
        if append:
            for line in appended:
                print(line)

    elif replace and changed:
        with open(filename, 'w') as f:
            for line in output:
                f.write(line+"\n")
            if append:
                for line in appended:
                    f.write(line+"\n")