# This file contains the code for the Azure DevOps Server webhook server.
# The server listens for incoming webhooks from Azure DevOps Server and forwards them to the PR Agent.
# ADO webhook documentation: https://learn.microsoft.com/en-us/azure/devops/service-hooks/services/webhooks?view=azure-devops

import json
import os
import re
import secrets
from urllib.parse import unquote

import uvicorn
from fastapi import APIRouter, Depends, FastAPI, HTTPException
from fastapi.security import HTTPBasic, HTTPBasicCredentials
from fastapi.encoders import jsonable_encoder
from starlette import status
from starlette.background import BackgroundTasks
from starlette.middleware import Middleware
from starlette.requests import Request
from starlette.responses import JSONResponse
from starlette_context.middleware import RawContextMiddleware

from pr_agent.agent.pr_agent import PRAgent, command2class
from pr_agent.algo.utils import update_settings_from_args
from pr_agent.config_loader import get_settings
from pr_agent.git_providers.utils import apply_repo_settings
from pr_agent.log import get_logger
from fastapi import Request, Depends
from fastapi.security import HTTPBasic, HTTPBasicCredentials
from pr_agent.log import LoggingFormat, get_logger, setup_logger

setup_logger(fmt=LoggingFormat.JSON, level="DEBUG")
security = HTTPBasic()
router = APIRouter()
available_commands_rgx = re.compile(r"^\/(" + "|".join(command2class.keys()) + r")\s*")
azure_devops_server = get_settings().get("azure_devops_server")
WEBHOOK_USERNAME = azure_devops_server.get("webhook_username")
WEBHOOK_PASSWORD = azure_devops_server.get("webhook_password")

def handle_request(
    background_tasks: BackgroundTasks, url: str, body: str, log_context: dict
):
    log_context["action"] = body
    log_context["api_url"] = url
    
    async def inner():
        with get_logger().contextualize(**log_context):
            await PRAgent().handle_request(url, body)

    background_tasks.add_task(inner)


# currently only basic auth is supported with azure webhooks
# for this reason, https must be enabled to ensure the credentials are not sent in clear text
def authorize(credentials: HTTPBasicCredentials = Depends(security)):
        is_user_ok = secrets.compare_digest(credentials.username, WEBHOOK_USERNAME)
        is_pass_ok = secrets.compare_digest(credentials.password, WEBHOOK_PASSWORD)
        if not (is_user_ok and is_pass_ok):
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail='Incorrect username or password.',
                headers={'WWW-Authenticate': 'Basic'},
            )


async def _perform_commands_azure(commands_conf: str, agent: PRAgent, api_url: str, log_context: dict):
    apply_repo_settings(api_url)
    commands = get_settings().get(f"azure_devops_server.{commands_conf}")
    for command in commands:
        try:
            split_command = command.split(" ")
            command = split_command[0]
            args = split_command[1:]
            other_args = update_settings_from_args(args)
            new_command = ' '.join([command] + other_args)
            get_logger().info(f"Performing command: {new_command}")
            with get_logger().contextualize(**log_context):
                await agent.handle_request(api_url, new_command)
        except Exception as e:
            get_logger().error(f"Failed to perform command {command}: {e}")


@router.post("/", dependencies=[Depends(authorize)])
async def handle_webhook(background_tasks: BackgroundTasks, request: Request):
    log_context = {"server_type": "azure_devops_server"}
    data = await request.json()
    get_logger().info(json.dumps(data))

    actions = []
    if data["eventType"] == "git.pullrequest.created": 
        # API V1 (latest)
        pr_url = unquote(data["resource"]["_links"]["web"]["href"].replace("_apis/git/repositories", "_git"))
        log_context["event"] = data["eventType"]
        log_context["api_url"] = pr_url
        await _perform_commands_azure("pr_commands", PRAgent(), pr_url, log_context)
        return
    elif data["eventType"] == "ms.vss-code.git-pullrequest-comment-event" and "content" in data["resource"]["comment"]:
        if available_commands_rgx.match(data["resource"]["comment"]["content"]):
            if(data["resourceVersion"] == "2.0"):
                repo = data["resource"]["pullRequest"]["repository"]["webUrl"]
                pr_url = unquote(f'{repo}/pullrequest/{data["resource"]["pullRequest"]["pullRequestId"]}')
                actions = [data["resource"]["comment"]["content"]]
            else: 
                # API V1 not supported as it does not contain the PR URL
                return JSONResponse(
                    status_code=status.HTTP_400_BAD_REQUEST,
                    content=json.dumps({"message": "version 1.0 webhook for Azure Devops PR comment is not supported. please upgrade to version 2.0"})),
        else:
            return JSONResponse(
                status_code=status.HTTP_400_BAD_REQUEST,
                content=json.dumps({"message": "Unsupported command"}),
            )
    else:
        return JSONResponse(
            status_code=status.HTTP_204_NO_CONTENT,
            content=json.dumps({"message": "Unsupported event"}),
        )

    log_context["event"] = data["eventType"]
    log_context["api_url"] = pr_url
    
    for action in actions:
        try:
            handle_request(background_tasks, pr_url, action, log_context)
        except Exception as e:
            get_logger().error("Azure DevOps Trigger failed. Error:" + str(e))
            return JSONResponse(
                status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                content=json.dumps({"message": "Internal server error"}),
            )
    return JSONResponse(
        status_code=status.HTTP_202_ACCEPTED, content=jsonable_encoder({"message": "webhook triggerd successfully"})
    )

@router.get("/")
async def root():
    return {"status": "ok"}
    
def start():
    app = FastAPI(middleware=[Middleware(RawContextMiddleware)])
    app.include_router(router)
    uvicorn.run(app, host="0.0.0.0", port=int(os.environ.get("PORT", "3000")))

if __name__ == "__main__":
    start()