import errno
import shutil
import os
import platform
from os.path import expanduser, exists, dirname
from configobj import ConfigObj


def config_location():
    if "XDG_CONFIG_HOME" in os.environ:
        return "%s/pgcli/" % expanduser(os.environ["XDG_CONFIG_HOME"])
    elif platform.system() == "Windows":
        return os.getenv("USERPROFILE") + "\\AppData\\Local\\dbcli\\pgcli\\"
    else:
        return expanduser("~/.config/pgcli/")


def load_config(usr_cfg, def_cfg=None):
    cfg = ConfigObj()
    cfg.merge(ConfigObj(def_cfg, interpolation=False))
    cfg.merge(ConfigObj(expanduser(usr_cfg), interpolation=False, encoding="utf-8"))
    cfg.filename = expanduser(usr_cfg)

    return cfg


def ensure_dir_exists(path):
    parent_dir = expanduser(dirname(path))
    os.makedirs(parent_dir, exist_ok=True)


def write_default_config(source, destination, overwrite=False):
    destination = expanduser(destination)
    if not overwrite and exists(destination):
        return

    ensure_dir_exists(destination)

    shutil.copyfile(source, destination)


def upgrade_config(config, def_config):
    cfg = load_config(config, def_config)
    cfg.write()


def get_config(pgclirc_file=None):
    from pgcli import __file__ as package_root

    package_root = os.path.dirname(package_root)

    pgclirc_file = pgclirc_file or "%sconfig" % config_location()

    default_config = os.path.join(package_root, "pgclirc")
    write_default_config(default_config, pgclirc_file)

    return load_config(pgclirc_file, default_config)


def get_casing_file(config):
    casing_file = config["main"]["casing_file"]
    if casing_file == "default":
        casing_file = config_location() + "casing"
    return casing_file