import asyncio
from collections import defaultdict
from datetime import datetime, timedelta
from typing import Callable
from urllib.parse import urlparse

from fastapi import Request, status
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from starlette.middleware.base import BaseHTTPMiddleware
from starlette.requests import Request as StarletteRequest
from starlette.types import ASGIApp

from openhands.server import shared
from openhands.server.auth import get_user_id
from openhands.server.types import SessionMiddlewareInterface


class LocalhostCORSMiddleware(CORSMiddleware):
    """
    Custom CORS middleware that allows any request from localhost/127.0.0.1 domains,
    while using standard CORS rules for other origins.
    """

    def __init__(self, app: ASGIApp, **kwargs) -> None:
        super().__init__(app, **kwargs)

    def is_allowed_origin(self, origin: str) -> bool:
        if origin:
            parsed = urlparse(origin)
            hostname = parsed.hostname or ''

            # Allow any localhost/127.0.0.1 origin regardless of port
            if hostname in ['localhost', '127.0.0.1']:
                return True

        # For missing origin or other origins, use the parent class's logic
        return super().is_allowed_origin(origin)


class CacheControlMiddleware(BaseHTTPMiddleware):
    """
    Middleware to disable caching for all routes by adding appropriate headers
    """

    async def dispatch(self, request, call_next):
        response = await call_next(request)
        if request.url.path.startswith('/assets'):
            # The content of the assets directory has fingerprinted file names so we cache aggressively
            response.headers['Cache-Control'] = 'public, max-age=2592000, immutable'
        else:
            response.headers['Cache-Control'] = (
                'no-cache, no-store, must-revalidate, max-age=0'
            )
            response.headers['Pragma'] = 'no-cache'
            response.headers['Expires'] = '0'
        return response


class InMemoryRateLimiter:
    history: dict
    requests: int
    seconds: int
    sleep_seconds: int

    def __init__(self, requests: int = 2, seconds: int = 1, sleep_seconds: int = 1):
        self.requests = requests
        self.seconds = seconds
        self.sleep_seconds = sleep_seconds
        self.history = defaultdict(list)
        self.sleep_seconds = sleep_seconds

    def _clean_old_requests(self, key: str) -> None:
        now = datetime.now()
        cutoff = now - timedelta(seconds=self.seconds)
        self.history[key] = [ts for ts in self.history[key] if ts > cutoff]

    async def __call__(self, request: Request) -> bool:
        key = request.client.host
        now = datetime.now()

        self._clean_old_requests(key)

        self.history[key].append(now)

        if len(self.history[key]) > self.requests * 2:
            return False
        elif len(self.history[key]) > self.requests:
            if self.sleep_seconds > 0:
                await asyncio.sleep(self.sleep_seconds)
                return True
            else:
                return False

        return True


class RateLimitMiddleware(BaseHTTPMiddleware):
    def __init__(self, app: ASGIApp, rate_limiter: InMemoryRateLimiter):
        super().__init__(app)
        self.rate_limiter = rate_limiter

    async def dispatch(self, request: StarletteRequest, call_next):
        if not self.is_rate_limited_request(request):
            return await call_next(request)
        ok = await self.rate_limiter(request)
        if not ok:
            return JSONResponse(
                status_code=429,
                content={'message': 'Too many requests'},
                headers={'Retry-After': '1'},
            )
        return await call_next(request)

    def is_rate_limited_request(self, request: StarletteRequest):
        if request.url.path.startswith('/assets'):
            return False
        # Put Other non rate limited checks here
        return True


class AttachConversationMiddleware(SessionMiddlewareInterface):
    def __init__(self, app):
        self.app = app

    def _should_attach(self, request) -> bool:
        """
        Determine if the middleware should attach a session for the given request.
        """
        if request.method == 'OPTIONS':
            return False

        conversation_id = ''
        if request.url.path.startswith('/api/conversation'):
            # FIXME: we should be able to use path_params
            path_parts = request.url.path.split('/')
            if len(path_parts) > 4:
                conversation_id = request.url.path.split('/')[3]
        if not conversation_id:
            return False

        request.state.sid = conversation_id

        return True

    async def _attach_conversation(self, request: Request) -> JSONResponse | None:
        """
        Attach the user's session based on the provided authentication token.
        """
        request.state.conversation = (
            await shared.conversation_manager.attach_to_conversation(request.state.sid)
        )
        if not request.state.conversation:
            return JSONResponse(
                status_code=status.HTTP_404_NOT_FOUND,
                content={'error': 'Session not found'},
            )
        return None

    async def _detach_session(self, request: Request) -> None:
        """
        Detach the user's session.
        """
        await shared.conversation_manager.detach_from_conversation(
            request.state.conversation
        )

    async def __call__(self, request: Request, call_next: Callable):
        if not self._should_attach(request):
            return await call_next(request)

        response = await self._attach_conversation(request)
        if response:
            return response

        try:
            # Continue processing the request
            response = await call_next(request)
        finally:
            # Ensure the session is detached
            await self._detach_session(request)

        return response


class GitHubTokenMiddleware(SessionMiddlewareInterface):
    def __init__(self, app):
        self.app = app

    async def __call__(self, request: Request, call_next: Callable):
        settings_store = await shared.SettingsStoreImpl.get_instance(
            shared.config, get_user_id(request)
        )
        settings = await settings_store.load()

        # TODO: To avoid checks like this we should re-add the abilty to have completely different middleware in SAAS as in OSS
        if getattr(request.state, 'github_token', None) is None:
            if settings and settings.github_token:
                request.state.github_token = settings.github_token
            else:
                request.state.github_token = None

        return await call_next(request)
