"""TOML ConfigurationSource.

Copyright (c) 2020 The Valiant Authors

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""
from pathlib import Path
from typing import Any, Dict, cast

from valiant.config import (
    BuildResultStatus,
    ConfigurationSource,
    ConfigurationSourceBuildResult,
)


class TomlSource(ConfigurationSource):
    """Reads config from a toml file."""

    def __init__(self, path: Path, optional: bool = True) -> None:
        """Initialiser.

        Args:
            path: the path to the TOML file
            optional: False is this file must be read, True otherwise
        """
        self._path = path
        self._optional = optional

    def build(self) -> ConfigurationSourceBuildResult:  # noqa: D102
        import toml

        if not self._optional and not self._path.exists():
            raise ValueError(
                f"The required configuration file does not exist: {self._path}"
            )

        if self._path.exists():
            return ConfigurationSourceBuildResult(
                source=str(self._path),
                status=BuildResultStatus.READ.value,
                result=cast(Dict[str, Any], toml.load(self._path)),
            )
        else:
            return ConfigurationSourceBuildResult(
                source=str(self._path),
                status=BuildResultStatus.NOT_READ.value,
                result={},
            )
