from datetime import datetime
import json
from typing import Any, Dict, Optional

import httpx
import aiohttp
from api.config import (
    DDG_API_ENDPOINT,
    DDG_STATUS_URL,
    MODEL_MAPPING,
    ALLOWED_MODELS,
    AGENT_MODE,
    TRENDING_AGENT_MODE,
    MODEL_PREFIXES,
    MODEL_REFERERS
)
from fastapi import HTTPException
from api.models import ChatRequest

from api.logger import setup_logger

import uuid

logger = setup_logger(__name__)

async def get_ddg_vqd():
    status_url = DDG_STATUS_URL

    headers = {
        'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36',
        'Accept': 'text/event-stream',
        'x-vqd-accept': '1'
    }

    async with aiohttp.ClientSession() as session:
        try:
            async with session.get(status_url, headers=headers) as response:
                if response.status == 200:
                    vqd = response.headers.get("x-vqd-4")
                    if not vqd:
                        logger.error("VQD token not found in response headers.")
                    else:
                        logger.debug(f"VQD token retrieved: {vqd}")
                    return vqd
                else:
                    logger.error(f"Error: Status code {response.status} when fetching VQD")
                    return None
        except Exception as e:
            logger.error(f"Error getting VQD: {e}")
            return None

def message_to_dict_ddg(message):
    if isinstance(message.content, str):
        return {"role": message.role, "content": message.content}
    else:
        # If DDG API does not support non-string content, raise an error
        raise ValueError("Message content must be a string.")

def strip_model_prefix(content: str, model_prefix: Optional[str] = None) -> str:
    """Remove the model prefix from the response content if present."""
    if model_prefix and content.startswith(model_prefix):
        logger.debug(f"Stripping prefix '{model_prefix}' from content.")
        return content[len(model_prefix):].strip()
    logger.debug("No prefix to strip from content.")
    return content

def create_chat_completion_data(
    content: str, model: str, timestamp: int, finish_reason: Optional[str] = None
) -> Dict[str, Any]:
    return {
        "id": f"chatcmpl-{uuid.uuid4()}",
        "object": "chat.completion.chunk",
        "created": timestamp,
        "model": model,
        "choices": [
            {
                "index": 0,
                "delta": {"content": content, "role": "assistant"},
                "finish_reason": finish_reason,
            }
        ],
        "usage": None,
    }

async def process_ddg_streaming_response(request: ChatRequest):
    agent_mode = AGENT_MODE.get(request.model, {})
    trending_agent_mode = TRENDING_AGENT_MODE.get(request.model, {})
    model_prefix = MODEL_PREFIXES.get(request.model, "")
    # referer_path and referer_url are not required unless specified by DDG API

    # Obtain VQD token
    vqd = await get_ddg_vqd()
    if not vqd:
        raise HTTPException(status_code=500, detail="Failed to obtain VQD token")

    # Build headers
    dynamic_headers = {
        'accept': 'text/event-stream',
        'content-type': 'application/json',
        'user-agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36',
        'x-vqd-4': vqd
    }

    # Construct message history
    try:
        message_history = [message_to_dict_ddg(msg) for msg in request.messages]
    except ValueError as ve:
        logger.error(f"Invalid message format: {ve}")
        raise HTTPException(status_code=400, detail=str(ve))

    json_data = {
        "model": MODEL_MAPPING.get(request.model, request.model),
        "messages": message_history,
        "previewToken": None,
        "userId": None,
        "codeModelMode": True,
        "agentMode": agent_mode,
        "trendingAgentMode": trending_agent_mode,
        "isMicMode": False,
        "userSystemPrompt": None,
        "maxTokens": request.max_tokens,
        "playgroundTopP": request.top_p,
        "playgroundTemperature": request.temperature,
        "isChromeExt": False,
        "githubToken": None,
        "clickedAnswer2": False,
        "clickedAnswer3": False,
        "clickedForceWebSearch": False,
        "visitFromDelta": False,
        "mobileClient": False,
        "userSelectedModel": MODEL_MAPPING.get(request.model, request.model),
    }

    logger.debug(f"Sending JSON payload to DDG API: {json.dumps(json_data)}")

    async with httpx.AsyncClient() as client:
        try:
            async with client.stream(
                "POST",
                DDG_API_ENDPOINT,
                headers=dynamic_headers,
                json=json_data,
                timeout=100,
            ) as response:
                response.raise_for_status()
                async for line in response.aiter_lines():
                    timestamp = int(datetime.now().timestamp())
                    if line:
                        content = line
                        if content.startswith("$@$v=undefined-rv1$@$"):
                            content = content[21:]
                        # Strip the model prefix from the response content
                        cleaned_content = strip_model_prefix(content, model_prefix)
                        yield f"data: {json.dumps(create_chat_completion_data(cleaned_content, request.model, timestamp))}\n\n"

                yield f"data: {json.dumps(create_chat_completion_data('', request.model, timestamp, 'stop'))}\n\n"
                yield "data: [DONE]\n\n"
        except httpx.HTTPStatusError as e:
            logger.error(f"HTTP error occurred: {e}")
            raise HTTPException(status_code=e.response.status_code, detail=str(e))
        except httpx.RequestError as e:
            logger.error(f"Error occurred during request: {e}")
            raise HTTPException(status_code=500, detail=str(e))

async def process_ddg_non_streaming_response(request: ChatRequest):
    agent_mode = AGENT_MODE.get(request.model, {})
    trending_agent_mode = TRENDING_AGENT_MODE.get(request.model, {})
    model_prefix = MODEL_PREFIXES.get(request.model, "")

    # Obtain VQD token
    vqd = await get_ddg_vqd()
    if not vqd:
        raise HTTPException(status_code=500, detail="Failed to obtain VQD token")

    # Build headers
    dynamic_headers = {
        'accept': 'application/json',
        'content-type': 'application/json',
        'user-agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36',
        'x-vqd-4': vqd
    }

    # Construct message history
    try:
        message_history = [message_to_dict_ddg(msg) for msg in request.messages]
    except ValueError as ve:
        logger.error(f"Invalid message format: {ve}")
        raise HTTPException(status_code=400, detail=str(ve))

    json_data = {
        "model": MODEL_MAPPING.get(request.model, request.model),
        "messages": message_history,
        "previewToken": None,
        "userId": None,
        "codeModelMode": True,
        "agentMode": agent_mode,
        "trendingAgentMode": trending_agent_mode,
        "isMicMode": False,
        "userSystemPrompt": None,
        "maxTokens": request.max_tokens,
        "playgroundTopP": request.top_p,
        "playgroundTemperature": request.temperature,
        "isChromeExt": False,
        "githubToken": None,
        "clickedAnswer2": False,
        "clickedAnswer3": False,
        "clickedForceWebSearch": False,
        "visitFromDelta": False,
        "mobileClient": False,
        "userSelectedModel": MODEL_MAPPING.get(request.model, request.model),
    }

    logger.debug(f"Sending JSON payload to DDG API: {json.dumps(json_data)}")

    async with httpx.AsyncClient() as client:
        try:
            response = await client.post(
                DDG_API_ENDPOINT,
                headers=dynamic_headers,
                json=json_data,
                timeout=100
            )
            response.raise_for_status()
            full_response = response.text
        except httpx.HTTPStatusError as e:
            logger.error(f"HTTP error occurred: {e}")
            raise HTTPException(status_code=e.response.status_code, detail=str(e))
        except httpx.RequestError as e:
            logger.error(f"Error occurred during request: {e}")
            raise HTTPException(status_code=500, detail=str(e))

    if full_response.startswith("$@$v=undefined-rv1$@$"):
        full_response = full_response[21:]

    cleaned_full_response = strip_model_prefix(full_response, model_prefix)

    return {
        "id": f"chatcmpl-{uuid.uuid4()}",
        "object": "chat.completion",
        "created": int(datetime.now().timestamp()),
        "model": request.model,
        "choices": [
            {
                "index": 0,
                "message": {"role": "assistant", "content": cleaned_full_response},
                "finish_reason": "stop",
            }
        ],
        "usage": None,
    }