package audittask

import (
	"context"

	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/audit"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/audit/auditor"
	"go.uber.org/zap"
)

// Listen starts the process of processing tasks from the queue.
//
// The listener is terminated by context.
func (m *Manager) Listen(ctx context.Context) {
	m.log.Info(logs.TaskmanagerProcessRoutine,
		zap.Uint32("queue_capacity", m.queueCap),
	)

	m.ch = make(chan *audit.Task, m.queueCap)

	for {
		select {
		case <-ctx.Done():
			m.log.Warn(logs.TaskmanagerStopListenerByContext,
				zap.String("error", ctx.Err().Error()),
			)
			m.workerPool.Release()

			return
		case task, ok := <-m.ch:
			if !ok {
				m.log.Warn(logs.TaskmanagerQueueChannelIsClosed)
				return
			}

			tCtx, tCancel := context.WithCancel(ctx) // cancel task in case of listen cancel
			go func() {
				select {
				case <-tCtx.Done(): // listen cancelled or task completed
					return
				case <-task.CancelChannel(): // new epoch
					tCancel()
				}
			}()

			m.handleTask(tCtx, task, tCancel)
		}
	}
}

func (m *Manager) handleTask(ctx context.Context, task *audit.Task, onCompleted func()) {
	pdpPool, err := m.pdpPoolGenerator()
	if err != nil {
		m.log.Error(logs.TaskmanagerCouldNotGeneratePDPWorkerPool,
			zap.String("error", err.Error()),
		)
		onCompleted()
		return
	}

	porPool, err := m.pdpPoolGenerator()
	if err != nil {
		m.log.Error(logs.TaskmanagerCouldNotGeneratePoRWorkerPool,
			zap.String("error", err.Error()),
		)
		onCompleted()
		return
	}

	auditContext := m.generateContext(task).
		WithPDPWorkerPool(pdpPool).
		WithPoRWorkerPool(porPool)

	if err := m.workerPool.Submit(func() { auditContext.Execute(ctx, onCompleted) }); err != nil {
		// may be we should report it
		m.log.Warn(logs.TaskmanagerCouldNotSubmitAuditTask)
		onCompleted()
	}
}

func (m *Manager) generateContext(task *audit.Task) *auditor.Context {
	return auditor.NewContext(m.ctxPrm).
		WithTask(task)
}