#!/usr/bin/env python3
# Copyright (c) 2008-11 Qtrac Ltd. All rights reserved.
# This program or module is free software: you can redistribute it and/or
# modify it under the terms of the GNU General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version. It is provided for educational
# purposes and is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.

import os
import sys
if sys.platform.startswith("win"):
    import glob

USE_SIMPLE_GET_FUNCTION = True


def main():
    modules = load_modules()
    get_file_type_functions = []
    for module in modules:
        get_file_type = get_function(module, "get_file_type")
        if get_file_type is not None:
            get_file_type_functions.append(get_file_type)

    for file in get_files(sys.argv[1:]):
        fh = None
        try:
            fh = open(file, "rb")
            magic = fh.read(1000)
            for get_file_type in get_file_type_functions:
                filetype = get_file_type(magic,
                                         os.path.splitext(file)[1])
                if filetype is not None:
                    print("{0:.<20}{1}".format(filetype, file))
                    break
            else:
                print("{0:.<20}{1}".format("Unknown", file))
        except EnvironmentError as err:
            print(err)
        finally:
            if fh is not None:
                fh.close()


if sys.platform.startswith("win"):
    def get_files(names):
        for name in names:
            if os.path.isfile(name):
                yield name
            else:
                for file in glob.iglob(name):
                    if not os.path.isfile(file):
                        continue
                    yield file
else:
    def get_files(names):
        return (file for file in names if os.path.isfile(file))


if USE_SIMPLE_GET_FUNCTION:
    def get_function(module, function_name):
        function = get_function.cache.get((module, function_name), None)
        if function is None:
            try:
                function = getattr(module, function_name)
                if not hasattr(function, "__call__"):
                    raise AttributeError()
                get_function.cache[module, function_name] = function
            except AttributeError:
                function = None
        return function
    get_function.cache = {}
else:
    def get_function(module, function_name):
        function = get_function.cache.get((module, function_name), None)
        if (function is None and
            (module, function_name) not in get_function.bad_cache):
            try:
                function = getattr(module, function_name)
                if not hasattr(function, "__call__"):
                    raise AttributeError()
                get_function.cache[module, function_name] = function
            except AttributeError:
                function = None
                get_function.bad_cache.add((module, function_name))
        return function
    get_function.cache = {}
    get_function.bad_cache = set()


if len(sys.argv) == 1 or sys.argv[1] in {"-h", "--help"}:
    print("usage: {0} [-1|-2] file1 [file2 [... fileN]]".format(
          os.path.basename(sys.argv[0])))
    sys.exit(2)
if sys.argv[1] == "-1":
    del sys.argv[1]
    # Version 1
    def load_modules():
        modules = []
        for name in os.listdir(os.path.dirname(__file__) or "."):
            if name.endswith(".py") and "magic" in name.lower():
                name = os.path.splitext(name)[0]
                if name.isidentifier() and name not in sys.modules:
                    try:
                        exec("import " + name)
                        modules.append(sys.modules[name])
                    except SyntaxError as err:
                        print(err)
        return modules
elif sys.argv[1] == "-2":
    del sys.argv[1]
    # Version 2
    def load_modules():
        modules = []
        for name in os.listdir(os.path.dirname(__file__) or "."):
            if name.endswith(".py") and "magic" in name.lower():
                filename = name
                name = os.path.splitext(name)[0]
                if name.isidentifier() and name not in sys.modules:
                    fh = None
                    try:
                        fh = open(filename, encoding="utf8")
                        code = fh.read()
                        module = type(sys)(name)
                        sys.modules[name] = module
                        exec(code, module.__dict__)
                        modules.append(module)
                    except (EnvironmentError, SyntaxError) as err:
                        sys.modules.pop(name, None)
                        print(err)
                    finally:
                        if fh is not None:
                            fh.close()
        return modules
else:
    # Version 3
    def load_modules():
        modules = []
        for name in os.listdir(os.path.dirname(__file__) or "."):
            if name.endswith(".py") and "magic" in name.lower():
                name = os.path.splitext(name)[0]
                if name.isidentifier() and name not in sys.modules:
                    try:
                        module = __import__(name)
                        modules.append(module)
                    except (ImportError, SyntaxError) as err:
                        print(err)
        return modules

main()