#  Copyright 2008-2015 Nokia Networks
#  Copyright 2016-     Robot Framework Foundation
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

from typing import TYPE_CHECKING

from robot.variables import contains_variable

from .typeconverters import UnknownConverter
from .typeinfo import TypeInfo

if TYPE_CHECKING:
    from robot.conf import LanguagesLike

    from .argumentspec import ArgumentSpec
    from .customconverters import CustomArgumentConverters


class ArgumentConverter:

    def __init__(
        self,
        arg_spec: "ArgumentSpec",
        custom_converters: "CustomArgumentConverters",
        dry_run: bool = False,
        languages: "LanguagesLike" = None,
    ):
        self.spec = arg_spec
        self.custom_converters = custom_converters
        self.dry_run = dry_run
        self.languages = languages

    def convert(self, positional, named):
        return self._convert_positional(positional), self._convert_named(named)

    def _convert_positional(self, positional):
        names = self.spec.positional
        converted = [self._convert(n, v) for n, v in zip(names, positional)]
        if self.spec.var_positional:
            converted.extend(
                self._convert(self.spec.var_positional, value)
                for value in positional[len(names) :]
            )
        return converted

    def _convert_named(self, named):
        names = set(self.spec.positional) | set(self.spec.named_only)
        var_named = self.spec.var_named
        return [
            (name, self._convert(name if name in names else var_named, value))
            for name, value in named
        ]

    def _convert(self, name, value):
        spec = self.spec
        if (
            spec.types is None
            or self.dry_run
            and contains_variable(value, identifiers="$@&%")
        ):
            return value
        conversion_error = None
        # Don't convert None if argument has None as a default value.
        # Python < 3.11 adds None to type hints automatically when using None as
        # a default value which preserves None automatically. This code keeps
        # the same behavior also with newer Python versions. We can consider
        # changing this once Python 3.11 is our minimum supported version.
        if value is None and name in spec.defaults and spec.defaults[name] is None:
            return value
        # Primarily convert arguments based on type hints.
        if name in spec.types:
            info: TypeInfo = spec.types[name]
            converter = info.get_converter(
                self.custom_converters,
                self.languages,
                allow_unknown=True,
            )
            # If type is unknown, don't attempt conversion. It would succeed, but
            # we want to, for now, attempt conversion based on the default value.
            if not isinstance(converter, UnknownConverter):
                try:
                    return converter.convert(value, name)
                except ValueError as err:
                    conversion_error = err
        # Try conversion also based on the default value type. We probably should
        # do this only if there is no explicit type hint, but Python < 3.11
        # handling `arg: type = None` differently than newer versions would mean
        # that conversion behavior depends on the Python version. Once Python 3.11
        # is our minimum supported version, we can consider reopening
        # https://github.com/robotframework/robotframework/issues/4881
        if name in spec.defaults:
            typ = type(spec.defaults[name])
            if typ is str:
                # Don't convert arguments to strings.
                info = TypeInfo()
            elif typ is int:
                # Try also conversion to float.
                info = TypeInfo.from_sequence([int, float])
            elif typ is type(None) and isinstance(value, str) and value == "":
                # Don't convert empty string to None.
                info = TypeInfo()
            else:
                info = TypeInfo.from_type(typ)
            try:
                return info.convert(value, name, languages=self.languages)
            except (ValueError, TypeError):
                pass
        if conversion_error:
            raise conversion_error
        return value
