import os
import errno
from os.path import abspath, dirname, join as pjoin

def check_path(path, create=False, write=True):
    """Check if given path exists and is readable as well as writable if specified;
    if create is true and the path doesn't exist, the directories will be created if possible"""
    path = os.path.expanduser(path)
    exist = os.path.isdir(path)
    if not exist and create:
        print("Directory '%s' does not exist, it will be created now" % path)
        # try to create the directory; if it should exist for whatever reason,
        # ignore it, otherwise report the error
        try:
            os.makedirs(path)
        except OSError as exception:
            if exception.errno == errno.EACCES:
                print_error("[ERROR] You don't have the permission to create directories in '%s'" % dirname(path))
                return False
            elif exception.errno != errno.EEXIST:
                raise
        return True
    elif not exist:
        print_error("[ERROR] Directory '%s' does not exist" % path)
        return False
    else:
        if not is_readable(path):
            print_error("[ERROR] Directory '%s' is not readable" % path)
            return False
        if write and not is_writable(path):
            print_error("[ERROR] Directory '%s' is not writable" % path)
            return False
    return True

def check_file(path, file):
    """Check if a file in a certain path exists and is readable;
    if the file argument is omitted only path is checked, it's recommended to use
    check_path instead for this case"""
    path = os.path.expanduser(path)
    if file is None:
        if not os.path.isfile(path):
            print_error("[ERROR] The file '%s' does not exist!" % (path))
            return False
        else:
            if not is_readable(path):
                print_error("[ERROR] The file '%s' is not readable!" % (path))
                return False
            return True
    path = get_path(path, file)
    if not os.path.isfile(path):
        print_error("[ERROR] The file '%s' does not exist!" % path)
        return False
    else:
        if not is_readable(path):
            print_error("[ERROR] The file '%s' is not readable!" % (path))
            return False
        return True

def check_permission(path, permission):
    """Check if the given permission is allowed for path"""
    if os.path.exists(path):
        return os.access(path, permission)
    else:
        return False

def is_readable(path):
    """Check if path is readable"""
    return check_permission(path, os.R_OK)

def is_writable(path):
    """Check if path is writable"""
    return check_permission(path, os.W_OK)

def is_executable(path):
    """Check if path is executable"""
    return check_permission(path, os.X_OK)

def get_path(path, file=None):
    """Get the absolute path of a given path and an optional file"""
    if not file:
        return abspath(os.path.expanduser(path))
    return abspath(os.path.expanduser(pjoin(path, file)))