from flask import Blueprint, Response, current_app, request
from sqlalchemy import select

from l4d2web.auth import current_user, require_login
from l4d2web.db import session_scope
from l4d2web.models import Job, JobLog


bp = Blueprint("job", __name__)


@bp.get("/jobs/<int:job_id>/stream")
@require_login
def stream_job(job_id: int) -> Response:
    user = current_user()
    assert user is not None

    last_seq = int(request.args.get("last_seq", "0"))
    limit = int(current_app.config["JOB_LOG_REPLAY_LIMIT"])

    with session_scope() as db:
        job = db.scalar(select(Job).where(Job.id == job_id, Job.user_id == user.id))
        if job is None:
            return Response(status=404)

    def generate():
        with session_scope() as db:
            rows = db.scalars(
                select(JobLog)
                .where(JobLog.job_id == job_id, JobLog.seq > last_seq)
                .order_by(JobLog.seq)
                .limit(limit)
            ).all()
            for row in rows:
                yield f"id: {row.seq}\n"
                yield f"event: {row.stream}\n"
                yield f"data: {row.line}\n\n"

    return Response(generate(), mimetype="text/event-stream")