import asyncio
import requests
from tenacity import (
    retry,
    stop_after_attempt,
    wait_random_exponential,
)
from openai import OpenAI, Stream
from openai.types.chat import ChatCompletion
from typing import Optional, List
from litellm import token_counter
from ..core.registry import register_model
from .model_configs import OpenRouterConfig
from .base_model import BaseLLM
from .model_utils import Cost, cost_manager


@register_model(config_cls=OpenRouterConfig, alias=["openrouter"])
class OpenRouterLLM(BaseLLM):

    def init_model(self):
        config: OpenRouterConfig = self.config
        self._client = self._init_client(config)
        self._default_ignore_fields = ["llm_type", "openrouter_key", "openrouter_base", "openrouter_model_base", "output_response"]
    
    def _init_client(self, config: OpenRouterConfig):
        client = OpenAI(
            api_key=config.openrouter_key,
            base_url=config.openrouter_base
        )
        return client

    def formulate_messages(self, prompts: List[str], system_messages: Optional[List[str]] = None) -> List[List[dict]]:
        if system_messages:
            assert len(prompts) == len(system_messages), f"the number of prompts ({len(prompts)}) is different from the number of system_messages ({len(system_messages)})"
        else:
            system_messages = [None] * len(prompts)
        
        messages_list = [] 
        for prompt, system_message in zip(prompts, system_messages):
            messages = [] 
            if system_message:
                messages.append({"role": "system", "content": system_message})
            messages.append({"role": "user", "content": prompt})
            messages_list.append(messages)

        return messages_list

    def update_completion_params(self, params1: dict, params2: dict) -> dict:
        config_params: list = self.config.get_config_params()
        for key, value in params2.items():
            if key in self._default_ignore_fields:
                continue
            if key not in config_params:
                continue
            params1[key] = value
        return params1

    def get_completion_params(self, **kwargs):
        completion_params = self.config.get_set_params(ignore=self._default_ignore_fields)
        completion_params = self.update_completion_params(completion_params, kwargs)
        return completion_params
    
    def get_stream_output(self, response: Stream, output_response: bool=True) -> str:
        output = ""
        for chunk in response:
            content = chunk.choices[0].delta.content
            if content:
                if output_response:
                    print(content, end="", flush=True)
                output += content
        if output_response:
            print("")
        return output
    
    async def get_stream_output_async(self, response, output_response: bool = False) -> str:
        output = ""
        async for chunk in response:
            content = chunk.choices[0].delta.content
            if content:
                if output_response:
                    print(content, end="", flush=True)
                output += content
        if output_response:
            print("")
        return output

    def get_completion_output(self, response: ChatCompletion, output_response: bool=True) -> str:
        output = response.choices[0].message.content
        if output_response:
            print(output)
        return output

    @retry(wait=wait_random_exponential(min=1, max=60), stop=stop_after_attempt(5))
    def single_generate(self, messages: List[dict], **kwargs) -> str:
        stream = kwargs.get("stream", self.config.stream)
        output_response = kwargs.get("output_response", self.config.output_response)

        try:
            completion_params = self.get_completion_params(**kwargs)
            response = self._client.chat.completions.create(messages=messages, **completion_params)
            if stream:
                output = self.get_stream_output(response, output_response=output_response)
                cost = self._stream_cost(messages=messages, output=output)
            else:
                output: str = self.get_completion_output(response=response, output_response=output_response)
                cost = self._completion_cost(response)
            self._update_cost(cost=cost)
        except Exception as e:
            raise RuntimeError(f"Error during single_generate of OpenRouterLLM: {str(e)}")
        
        return output
        
    def batch_generate(self, batch_messages: List[List[dict]], **kwargs) -> List[str]:
        return [self.single_generate(messages=one_messages, **kwargs) for one_messages in batch_messages]

    async def single_generate_async(self, messages: List[dict], **kwargs) -> str:
        stream = kwargs.get("stream", self.config.stream)
        output_response = kwargs.get("output_response", self.config.output_response)

        try:
            isolated_client = self._init_client(self.config)
            completion_params = self.get_completion_params(**kwargs)

            loop = asyncio.get_event_loop()
            response = await loop.run_in_executor(
                None, 
                lambda: isolated_client.chat.completions.create(
                    messages=messages, 
                    **completion_params
                )
            )

            if stream:
                if hasattr(response, "__aiter__"):
                    output = await self.get_stream_output_async(response, output_response=output_response)
                else:
                    output = self.get_stream_output(response, output_response=output_response)
                cost = self._stream_cost(messages=messages, output=output)
            else:
                output: str = self.get_completion_output(response=response, output_response=output_response)
                cost = self._completion_cost(response)
            self._update_cost(cost=cost)
        
        except Exception as e:
            raise RuntimeError(f"Error during single_generate_async of OpenRouterLLM: {str(e)}")

        return output
    
    def _completion_cost(self, response: ChatCompletion) -> Cost:
        input_tokens = response.usage.prompt_tokens
        output_tokens = response.usage.completion_tokens
        return self._compute_cost(input_tokens=input_tokens, output_tokens=output_tokens)

    def _stream_cost(self, messages: List[dict], output: str) -> Cost:
        model: str = self.config.model
        input_tokens = token_counter(model=model, messages=messages)
        output_tokens = token_counter(model=model, text=output)
        return self._compute_cost(input_tokens=input_tokens, output_tokens=output_tokens)
    
    def _compute_cost(self, input_tokens: int, output_tokens: int) -> Cost:
        
        input_cost_per_token, output_cost_per_token = self._get_cost()
        input_cost = input_tokens * input_cost_per_token
        output_cost = output_tokens * output_cost_per_token
        
        cost = Cost(input_tokens=input_tokens, output_tokens=output_tokens, input_cost=input_cost, output_cost=output_cost)
        return cost
    
    def _update_cost(self, cost: Cost):
        cost_manager.update_cost(cost=cost, model=self.config.model)
        

    def _get_cost(self):
        url = self.config.openrouter_model_base
        response = requests.get(url)
        data = response.json()
        
        for model in data['data']:
            if model['id'] == self.config.model:
                pricing = model.get('pricing',{})
                input_cost = float(pricing.get('prompt', 0))
                output_cost = float(pricing.get('completion', 0))
                return input_cost, output_cost
            
        return 0, 0