# Copyright 2024 the LlamaFactory team.
#
# 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.

import re
from abc import ABC, abstractmethod
from collections import namedtuple
from dataclasses import dataclass, field
from typing import Optional, Union, List
from typing import Sequence, Dict, Set

SLOTS = Sequence[Union[str, Set[str], Dict[str, str]]]


@dataclass
class Formatter(ABC):
    slots: SLOTS = field(default_factory=list)
    tool_format: Optional[str] = None

    @abstractmethod
    def apply(self, **kwargs) -> SLOTS:
        r"""
        Forms a list of slots according to the inputs to encode.
        """
        ...

    def extract(self, content: str) -> Union[str, List["FunctionCall"]]:
        r"""
        Extract a list of tuples from the response message if using tools.

        Each tuple consists of function name and function arguments.
        """
        raise NotImplementedError


@dataclass
class EmptyFormatter(Formatter):
    def __post_init__(self):
        has_placeholder = False
        for slot in filter(lambda s: isinstance(s, str), self.slots):
            if re.search(r"\{\{[a-zA-Z_][a-zA-Z0-9_]*\}\}", slot):
                has_placeholder = True

        if has_placeholder:
            raise ValueError("Empty formatter should not contain any placeholder.")

    def apply(self, **kwargs) -> SLOTS:
        return self.slots


@dataclass
class StringFormatter(Formatter):
    def __post_init__(self):
        has_placeholder = False
        for slot in filter(lambda s: isinstance(s, str), self.slots):
            if re.search(r"\{\{[a-zA-Z_][a-zA-Z0-9_]*\}\}", slot):
                has_placeholder = True

        if not has_placeholder:
            raise ValueError("A placeholder is required in the string formatter.")

    def apply(self, **kwargs) -> SLOTS:
        elements = []
        for slot in self.slots:
            if isinstance(slot, str):
                for name, value in kwargs.items():
                    if not isinstance(value, str):
                        raise RuntimeError("Expected a string, got {}".format(value))

                    slot = slot.replace("{{" + name + "}}", value, 1)
                elements.append(slot)
            elif isinstance(slot, (dict, set)):
                elements.append(slot)
            else:
                raise RuntimeError("Input must be string, set[str] or dict[str, str], got {}".format(type(slot)))

        return elements


FunctionCall = namedtuple("FunctionCall", ["name", "arguments"])