from collections.abc import Generator
from enum import Enum
from hashlib import md5
from json import dumps, loads
from typing import Any, Union

from requests import post

from core.model_runtime.model_providers.baichuan.llm.baichuan_turbo_errors import (
    BadRequestError,
    InsufficientAccountBalance,
    InternalServerError,
    InvalidAPIKeyError,
    InvalidAuthenticationError,
    RateLimitReachedError,
)


class BaichuanMessage:
    class Role(Enum):
        USER = 'user'
        ASSISTANT = 'assistant'
        # Baichuan does not have system message
        _SYSTEM = 'system'

    role: str = Role.USER.value
    content: str
    usage: dict[str, int] = None
    stop_reason: str = ''

    def to_dict(self) -> dict[str, Any]:
        return {
            'role': self.role,
            'content': self.content,
        }
    
    def __init__(self, content: str, role: str = 'user') -> None:
        self.content = content
        self.role = role

class BaichuanModel:
    api_key: str
    secret_key: str

    def __init__(self, api_key: str, secret_key: str = '') -> None:
        self.api_key = api_key
        self.secret_key = secret_key

    def _model_mapping(self, model: str) -> str:
        return {
            'baichuan2-turbo': 'Baichuan2-Turbo',
            'baichuan2-turbo-192k': 'Baichuan2-Turbo-192k',
            'baichuan2-53b': 'Baichuan2-53B',
        }[model]

    def _handle_chat_generate_response(self, response) -> BaichuanMessage:
            resp = response.json()
            choices = resp.get('choices', [])
            message = BaichuanMessage(content='', role='assistant')
            for choice in choices:
                message.content += choice['message']['content']
                message.role = choice['message']['role']
                if choice['finish_reason']:
                    message.stop_reason = choice['finish_reason']

            if 'usage' in resp:
                message.usage = {
                    'prompt_tokens': resp['usage']['prompt_tokens'],
                    'completion_tokens': resp['usage']['completion_tokens'],
                    'total_tokens': resp['usage']['total_tokens'],
                }
            
            return message
    
    def _handle_chat_stream_generate_response(self, response) -> Generator:
        for line in response.iter_lines():
            if not line:
                continue
            line = line.decode('utf-8')
            # remove the first `data: ` prefix
            if line.startswith('data:'):
                line = line[5:].strip()
            try:
                data = loads(line)
            except Exception as e:
                if line.strip() == '[DONE]':
                    return
            choices = data.get('choices', [])
            # save stop reason temporarily
            stop_reason = ''
            for choice in choices:
                if 'finish_reason' in choice and choice['finish_reason']:
                    stop_reason = choice['finish_reason']

                if len(choice['delta']['content']) == 0:
                    continue
                yield BaichuanMessage(**choice['delta'])

            # if there is usage, the response is the last one, yield it and return
            if 'usage' in data:
                message = BaichuanMessage(content='', role='assistant')
                message.usage = {
                    'prompt_tokens': data['usage']['prompt_tokens'],
                    'completion_tokens': data['usage']['completion_tokens'],
                    'total_tokens': data['usage']['total_tokens'],
                }
                message.stop_reason = stop_reason
                yield message

    def _build_parameters(self, model: str, stream: bool, messages: list[BaichuanMessage],
                               parameters: dict[str, Any]) \
        -> dict[str, Any]:
        if model == 'baichuan2-turbo' or model == 'baichuan2-turbo-192k' or model == 'baichuan2-53b':
            prompt_messages = []
            for message in messages:
                if message.role == BaichuanMessage.Role.USER.value or message.role == BaichuanMessage.Role._SYSTEM.value:
                    # check if the latest message is a user message
                    if len(prompt_messages) > 0 and prompt_messages[-1]['role'] == BaichuanMessage.Role.USER.value:
                        prompt_messages[-1]['content'] += message.content
                    else:
                        prompt_messages.append({
                            'content': message.content,
                            'role': BaichuanMessage.Role.USER.value,
                        })
                elif message.role == BaichuanMessage.Role.ASSISTANT.value:
                    prompt_messages.append({
                        'content': message.content,
                        'role': message.role,
                    })
            # [baichuan] frequency_penalty must be between 1 and 2
            if 'frequency_penalty' in parameters:
                if parameters['frequency_penalty'] < 1 or parameters['frequency_penalty'] > 2:
                    parameters['frequency_penalty'] = 1

            # turbo api accepts flat parameters
            return {
                'model': self._model_mapping(model),
                'stream': stream,
                'messages': prompt_messages,
                **parameters,
            }
        else:
            raise BadRequestError(f"Unknown model: {model}")
        
    def _build_headers(self, model: str, data: dict[str, Any]) -> dict[str, Any]:
        if model == 'baichuan2-turbo' or model == 'baichuan2-turbo-192k' or model == 'baichuan2-53b':
            # there is no secret key for turbo api
            return {
                'Content-Type': 'application/json',
                'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) ',
                'Authorization': 'Bearer ' + self.api_key,
            }
        else:
            raise BadRequestError(f"Unknown model: {model}")
        
    def _calculate_md5(self, input_string):
        return md5(input_string.encode('utf-8')).hexdigest()

    def generate(self, model: str, stream: bool, messages: list[BaichuanMessage], 
                 parameters: dict[str, Any], timeout: int) \
        -> Union[Generator, BaichuanMessage]:
        
        if model == 'baichuan2-turbo' or model == 'baichuan2-turbo-192k' or model == 'baichuan2-53b':
            api_base = 'https://api.baichuan-ai.com/v1/chat/completions'
        else:
            raise BadRequestError(f"Unknown model: {model}")
        
        try:
            data = self._build_parameters(model, stream, messages, parameters)
            headers = self._build_headers(model, data)
        except KeyError:
            raise InternalServerError(f"Failed to build parameters for model: {model}")

        try:
            response = post(
                url=api_base,
                headers=headers,
                data=dumps(data),
                timeout=timeout,
                stream=stream
            )
        except Exception as e:
            raise InternalServerError(f"Failed to invoke model: {e}")
        
        if response.status_code != 200:
            try:
                resp = response.json()
                # try to parse error message
                err = resp['error']['code']
                msg = resp['error']['message']
            except Exception as e:
                raise InternalServerError(f"Failed to convert response to json: {e} with text: {response.text}")

            if err == 'invalid_api_key':
                raise InvalidAPIKeyError(msg)
            elif err == 'insufficient_quota':
                raise InsufficientAccountBalance(msg)
            elif err == 'invalid_authentication':
                raise InvalidAuthenticationError(msg)
            elif 'rate' in err:
                raise RateLimitReachedError(msg)
            elif 'internal' in err:
                raise InternalServerError(msg)
            elif err == 'api_key_empty':
                raise InvalidAPIKeyError(msg)
            else:
                raise InternalServerError(f"Unknown error: {err} with message: {msg}")
            
        if stream:
            return self._handle_chat_stream_generate_response(response)
        else:
            return self._handle_chat_generate_response(response)