package intentflow

import (
	"context"

	"chat-agent-system/internal/app/uow"
)

// DispatchEligible is the production step dispatcher. It reuses ClaimStep,
// ExecuteClaimed, and RecoverReceipt on the existing intent_plan_steps ledger.
// It must not introduce a second decision queue or step state machine.
//
// After a crash between domain receipt and plan write-back, RecoverReceipt
// replays the owner receipt without re-executing the side effect.
func (p *Plans) DispatchEligible(ctx context.Context, workerID, planID string) (*PlanView, error) {
	if workerID == "" || planID == "" {
		return nil, ErrPlanDependencyInvalid
	}
	var prin Principal
	var ids []string
	err := p.withTx(ctx, func(ctx context.Context, scope uow.TxScope) error {
		plan, err := p.store.GetPlan(ctx, scope, planID)
		if err != nil {
			return err
		}
		if plan == nil {
			return ErrPlanNotFoundOrHidden
		}
		prin = plan.Principal
		for _, s := range plan.Steps {
			if s.Status == StepEligible || s.Status == StepPending || s.Status == StepRunning {
				ids = append(ids, s.StepID)
			}
		}
		return nil
	})
	if err != nil {
		return nil, err
	}
	var last *PlanView
	var firstErr error
	for _, id := range ids {
		claimed, claimErr := p.ClaimStep(ctx, workerID, planID, id)
		if claimErr != nil {
			if firstErr == nil {
				firstErr = claimErr
			}
			continue
		}
		if claimed == nil {
			continue
		}
		got, execErr := p.ExecuteClaimed(ctx, claimed)
		if execErr != nil {
			recovered, recErr := p.RecoverReceipt(ctx, claimed)
			if recErr == nil && recovered != nil {
				last = recovered
				continue
			}
			if firstErr == nil {
				firstErr = execErr
			}
			continue
		}
		last = got
	}
	if last == nil {
		view, getErr := p.GetPlan(ctx, prin, planID)
		if firstErr != nil {
			return view, firstErr
		}
		return view, getErr
	}
	return last, firstErr
}