"""Import configuration files and returns default values if undefined."""

# Standard Library
import typing as t
from pathlib import Path

# Third Party
import yaml
from pydantic import ValidationError

# Project
from hyperglass.log import log, enable_file_logging, enable_syslog_logging
from hyperglass.settings import Settings
from hyperglass.models.ui import UIParameters
from hyperglass.util.files import check_path
from hyperglass.models.directive import Directive, Directives
from hyperglass.exceptions.private import ConfigError, ConfigMissing
from hyperglass.models.config.params import Params
from hyperglass.models.config.devices import Devices

# Local
from .markdown import get_markdown
from .validation import validate_config

__all__ = (
    "init_params",
    "init_directives",
    "init_devices",
    "init_ui_params",
)

# Project Directories
CONFIG_PATH = Settings.app_path
CONFIG_FILES = (
    ("hyperglass.yaml", False),
    ("devices.yaml", True),
    ("directives.yaml", False),
)


def _check_config_files(directory: Path):
    """Verify config files exist and are readable."""

    files = ()

    for file in CONFIG_FILES:
        file_name, required = file
        file_path = directory / file_name

        checked = check_path(file_path)

        if checked is None and required:
            raise ConfigMissing(missing_item=str(file_path))

        if checked is None and not required:
            log.warning(
                "'{f}' was not found, but is not required to run hyperglass. "
                + "Defaults will be used.",
                f=str(file_path),
            )
        files += (checked,)

    return files


CONFIG_MAIN, CONFIG_DEVICES, CONFIG_DIRECTIVES = _check_config_files(CONFIG_PATH)


def _config_required(config_path: Path) -> t.Dict[str, t.Any]:
    try:
        with config_path.open("r") as cf:
            config = yaml.safe_load(cf)

    except (yaml.YAMLError, yaml.MarkedYAMLError) as yaml_error:
        raise ConfigError(message="Error reading YAML file: '{e}'", e=yaml_error)

    if config is None:
        raise ConfigMissing(missing_item=config_path.name)

    return config


def _config_optional(config_path: Path) -> t.Dict[str, t.Any]:

    config = {}

    if config_path is None:
        return config

    else:
        try:
            with config_path.open("r") as cf:
                config = yaml.safe_load(cf) or {}

        except (yaml.YAMLError, yaml.MarkedYAMLError) as yaml_error:
            raise ConfigError(message="Error reading YAML file: '{e}'", e=yaml_error)

    return config


def _get_directives(data: t.Dict[str, t.Any]) -> "Directives":
    directives = ()
    for name, directive in data.items():
        try:
            directives += (Directive(id=name, **directive),)
        except ValidationError as err:
            raise ConfigError(
                message="Validation error in directive '{d}': '{e}'", d=name, e=err
            ) from err
    return Directives(*directives)


def init_params() -> "Params":
    """Validate & initialize configuration parameters."""
    user_config = _config_optional(CONFIG_MAIN)
    # Map imported user configuration to expected schema.
    log.debug("Unvalidated configuration from {}: {}", CONFIG_MAIN, user_config)
    params = validate_config(config=user_config, importer=Params)

    # Set up file logging once configuration parameters are initialized.
    enable_file_logging(
        logger=log,
        log_directory=params.logging.directory,
        log_format=params.logging.format,
        log_max_size=params.logging.max_size,
    )

    # Set up syslog logging if enabled.
    if params.logging.syslog is not None and params.logging.syslog.enable:
        enable_syslog_logging(
            logger=log,
            syslog_host=params.logging.syslog.host,
            syslog_port=params.logging.syslog.port,
        )

    if params.logging.http is not None and params.logging.http.enable:
        log.debug("HTTP logging is enabled")

    # Perform post-config initialization string formatting or other
    # functions that require access to other config levels. E.g.,
    # something in 'params.web.text' needs to be formatted with a value
    # from params.
    try:
        params.web.text.subtitle = params.web.text.subtitle.format(
            **params.dict(exclude={"web", "queries", "messages"})
        )

        # If keywords are unmodified (default), add the org name &
        # site_title.
        if Params().site_keywords == params.site_keywords:
            params.site_keywords = sorted(
                {*params.site_keywords, params.org_name, params.site_title}
            )
    except KeyError:
        pass

    return params


def init_directives() -> "Directives":
    """Validate & initialize directives."""
    # Map imported user directives to expected schema.
    _user_directives = _config_optional(CONFIG_DIRECTIVES)
    log.debug("Unvalidated directives from {!s}: {}", CONFIG_DIRECTIVES, _user_directives)
    return _get_directives(_user_directives)


def init_devices() -> "Devices":
    """Validate & initialize devices."""
    _user_devices = _config_required(CONFIG_DEVICES)
    log.debug("Unvalidated devices from {}: {}", CONFIG_DEVICES, _user_devices)
    return Devices(_user_devices.get("devices", _user_devices.get("routers", [])))


def init_ui_params(*, params: "Params", devices: "Devices") -> "UIParameters":
    """Validate & initialize UI parameters."""

    # Project
    from hyperglass.defaults import CREDIT
    from hyperglass.constants import PARSED_RESPONSE_FIELDS, __version__

    content_greeting = get_markdown(
        config_path=params.web.greeting, default="", params={"title": params.web.greeting.title},
    )
    content_credit = CREDIT.format(version=__version__)

    _ui_params = params.frontend()
    _ui_params["web"]["logo"]["light_format"] = params.web.logo.light.suffix
    _ui_params["web"]["logo"]["dark_format"] = params.web.logo.dark.suffix

    return UIParameters(
        **_ui_params,
        version=__version__,
        networks=devices.networks(params),
        parsed_data_fields=PARSED_RESPONSE_FIELDS,
        content={"credit": content_credit, "greeting": content_greeting},
    )