package web

import "context"

// StartWorker registers ownership before launching a worker. Shutdown excludes
// admission under the same lock, then waits through output/history persistence.
func (jm *JobManager) StartWorker(jobID string, work func()) bool {
	jm.mu.Lock()
	if jm.closing {
		jm.mu.Unlock()
		jm.SetError(jobID, context.Canceled, "Server shutdown started before the worker could run")
		return false
	}
	jm.workers.Add(1)
	jm.mu.Unlock()
	go func() {
		defer jm.workers.Done()
		work()
	}()
	return true
}

func (jm *JobManager) stopAdmissionAndCancel() {
	jm.mu.Lock()
	defer jm.mu.Unlock()
	jm.closing = true
	for _, job := range jm.jobs {
		// A committed operation must finish or roll back and persist its result.
		// Cancelling a package manager mid-transaction is not a safe shutdown.
		if !job.commitStarted && job.cancel != nil {
			job.cancel()
			job.Status = "cancelling"
			job.Message = "Server shutting down; waiting for the worker to stop"
		}
	}
}