package application

import (
	"context"
	"time"

	"git.cin.su/m/Assistant/contracts/work"
	"git.cin.su/m/Assistant/modules/work/ports"
)

type WorkerCycleResult struct {
	RecoveredClaims int64
	DispatchID      string
	Completed       bool
	Idle            bool
}

const transientDispatchRetryDelay = time.Second

func retryClaimedDispatch(ctx context.Context, store ports.WorkerStore, dispatchID, workerID string, now time.Time) error {
	return store.RetryDispatch(ctx, dispatchID, workerID, now.UnixMilli(), transientDispatchRetryDelay)
}

// RecoverOnlyWorkerCycle keeps durable recovery alive while the real executor
// capability is absent. It intentionally does not claim a dispatch: a missing
// executor must never be represented as successful work.
func RecoverOnlyWorkerCycle(ctx context.Context, store ports.WorkerStore, now time.Time, staleAfter time.Duration) (WorkerCycleResult, error) {
	recovered, err := store.RecoverStaleClaims(ctx, now.UnixMilli(), staleAfter.Milliseconds())
	return WorkerCycleResult{RecoveredClaims: recovered, Idle: err == nil}, err
}

func ExecuteWorkerCycle(ctx context.Context, store ports.WorkerStore, workerID string, token work.AgentFencingToken, now time.Time, staleAfter, leaseTTL time.Duration) (WorkerCycleResult, error) {
	recovered, err := store.RecoverStaleClaims(ctx, now.UnixMilli(), staleAfter.Milliseconds())
	if err != nil {
		return WorkerCycleResult{}, err
	}
	item, err := store.ClaimNextDispatch(ctx, workerID, now.UnixMilli())
	if err != nil {
		return WorkerCycleResult{RecoveredClaims: recovered}, err
	}
	if item.DispatchID == "" {
		return WorkerCycleResult{RecoveredClaims: recovered, Idle: true}, nil
	}
	intent, err := store.LoadDispatchIntent(ctx, item.DispatchID)
	if err != nil {
		_ = retryClaimedDispatch(ctx, store, item.DispatchID, workerID, now)
		return WorkerCycleResult{RecoveredClaims: recovered, DispatchID: item.DispatchID}, err
	}
	if _, err := ExecuteDryRunDispatch(ctx, store, intent, workerID, token, now, leaseTTL); err != nil {
		_ = retryClaimedDispatch(ctx, store, item.DispatchID, workerID, now)
		return WorkerCycleResult{RecoveredClaims: recovered, DispatchID: item.DispatchID}, err
	}
	if err := store.CompleteDispatch(ctx, item.DispatchID, workerID, work.AgentDispatchCompleted, now.UnixMilli()); err != nil {
		return WorkerCycleResult{RecoveredClaims: recovered, DispatchID: item.DispatchID}, err
	}
	return WorkerCycleResult{RecoveredClaims: recovered, DispatchID: item.DispatchID, Completed: true}, nil
}

func ExecuteWorkerCycleWithExecutor(ctx context.Context, store ports.WorkerStore, executor ports.AgentExecutor, workerID string, token work.AgentFencingToken, now time.Time, staleAfter, leaseTTL time.Duration) (WorkerCycleResult, error) {
	recovered, err := store.RecoverStaleClaims(ctx, now.UnixMilli(), staleAfter.Milliseconds())
	if err != nil {
		return WorkerCycleResult{}, err
	}
	item, err := store.ClaimNextDispatch(ctx, workerID, now.UnixMilli())
	if err != nil {
		return WorkerCycleResult{RecoveredClaims: recovered}, err
	}
	if item.DispatchID == "" {
		return WorkerCycleResult{RecoveredClaims: recovered, Idle: true}, nil
	}
	intent, err := store.LoadDispatchIntent(ctx, item.DispatchID)
	if err != nil {
		_ = retryClaimedDispatch(ctx, store, item.DispatchID, workerID, now)
		return WorkerCycleResult{RecoveredClaims: recovered, DispatchID: item.DispatchID}, err
	}
	result, err := ExecuteAgentDispatch(ctx, store, executor, intent, workerID, token, now, leaseTTL)
	if err != nil {
		_ = retryClaimedDispatch(ctx, store, item.DispatchID, workerID, now)
		return WorkerCycleResult{RecoveredClaims: recovered, DispatchID: item.DispatchID}, err
	}
	if result.State != work.AgentExecutionCompleted {
		if err := retryClaimedDispatch(ctx, store, item.DispatchID, workerID, now); err != nil {
			return WorkerCycleResult{RecoveredClaims: recovered, DispatchID: item.DispatchID}, err
		}
		return WorkerCycleResult{RecoveredClaims: recovered, DispatchID: item.DispatchID}, nil
	}
	if err := store.CompleteDispatch(ctx, item.DispatchID, workerID, work.AgentDispatchCompleted, now.UnixMilli()); err != nil {
		return WorkerCycleResult{RecoveredClaims: recovered, DispatchID: item.DispatchID}, err
	}
	return WorkerCycleResult{RecoveredClaims: recovered, DispatchID: item.DispatchID, Completed: true}, nil
}