import asyncio
import hashlib
import hmac
import os

from fastapi import APIRouter, BackgroundTasks, Header, HTTPException, Request
from fastapi.responses import JSONResponse
from integrations.github.data_collector import GitHubDataCollector
from integrations.github.github_manager import GithubManager
from integrations.models import Message, SourceType
from server.auth.constants import (
    AUTOMATION_EVENT_FORWARDING_ENABLED,
    GITHUB_APP_WEBHOOK_SECRET,
)
from server.auth.token_manager import TokenManager
from server.services.automation_event_service import AutomationEventService

from openhands.app_server.integrations.provider import ProviderType
from openhands.app_server.utils.logger import openhands_logger as logger

# Environment variable to disable GitHub webhooks
GITHUB_WEBHOOKS_ENABLED = os.environ.get('GITHUB_WEBHOOKS_ENABLED', '1') in (
    '1',
    'true',
)
github_integration_router = APIRouter(prefix='/integration')
token_manager = TokenManager()
data_collector = GitHubDataCollector()
github_manager = GithubManager(token_manager, data_collector)
automation_event_service = AutomationEventService(token_manager)


def verify_github_signature(payload: bytes, signature: str):
    if not signature:
        raise HTTPException(
            status_code=403, detail='x-hub-signature-256 header is missing!'
        )

    expected_signature = (
        'sha256='
        + hmac.new(
            GITHUB_APP_WEBHOOK_SECRET.encode('utf-8'),
            msg=payload,
            digestmod=hashlib.sha256,
        ).hexdigest()
    )

    if not hmac.compare_digest(expected_signature, signature):
        raise HTTPException(status_code=403, detail="Request signatures didn't match!")


@github_integration_router.post('/github/events')
async def github_events(
    request: Request,
    background_tasks: BackgroundTasks,
    x_hub_signature_256: str = Header(None),
    x_github_event: str = Header(None),
):
    # Check if GitHub webhooks are enabled
    if not GITHUB_WEBHOOKS_ENABLED:
        logger.info('GitHub webhooks disabled by GITHUB_WEBHOOKS_ENABLED env variable')
        return JSONResponse(
            status_code=200,
            content={'message': 'GitHub webhooks are currently disabled.'},
        )

    try:
        # Add timeout to prevent hanging on slow/stalled clients
        payload = await asyncio.wait_for(request.body(), timeout=15.0)
        verify_github_signature(payload, x_hub_signature_256)

        payload_data = await request.json()
        installation_id = payload_data.get('installation', {}).get('id')

        if not installation_id:
            return JSONResponse(
                status_code=400,
                content={'error': 'Installation ID is missing in the payload.'},
            )

        # Forward to automation service (fire-and-forget background task)
        if AUTOMATION_EVENT_FORWARDING_ENABLED:
            background_tasks.add_task(
                automation_event_service.forward_event,
                provider=ProviderType.GITHUB,
                payload=payload_data,
                installation_id=installation_id,
            )

        # Existing resolver bot processing
        message_payload = {'payload': payload_data, 'installation': installation_id}
        message = Message(source=SourceType.GITHUB, message=message_payload)
        await github_manager.receive_message(message)

        return JSONResponse(
            status_code=200,
            content={'message': 'GitHub events endpoint reached successfully.'},
        )
    except asyncio.TimeoutError:
        logger.warning('GitHub webhook request timed out waiting for request body')
        return JSONResponse(
            status_code=408,
            content={'error': 'Request timeout - client took too long to send data.'},
        )
    except Exception:
        logger.exception('Error processing GitHub event', stack_info=True)
        return JSONResponse(status_code=400, content={'error': 'Invalid payload.'})