package settlement

import (
	"context"
	"fmt"
	"time"

	"gl/domain/ledger"
)

type Repository interface {
	ClaimDue(context.Context, string, int, time.Time) ([]ledger.Settlement, error)
	Save(context.Context, ledger.Settlement, string) error
}

type Submitter interface {
	Submit(context.Context, ledger.Settlement) (string, error)
}

type Worker struct {
	Repository  Repository
	Submitter   Submitter
	WorkerID    string
	MaxAttempts int
	Now         func() time.Time
}

func (w Worker) RunOnce(ctx context.Context, limit int) error {
	if w.Repository == nil || w.Submitter == nil || w.WorkerID == "" || limit <= 0 {
		return fmt.Errorf("settlement worker is not configured")
	}
	now := time.Now().UTC()
	if w.Now != nil {
		now = w.Now().UTC()
	}
	records, err := w.Repository.ClaimDue(ctx, w.WorkerID, limit, now)
	if err != nil {
		return err
	}
	for _, record := range records {
		record.Attempts++
		hash, submitErr := w.Submitter.Submit(ctx, record)
		if submitErr != nil {
			record = record.Retry(now, w.MaxAttempts, submitErr)
		} else {
			// Horizon returns success only after the transaction is accepted into
			// a ledger, so a successful response is already confirmation.
			record.Status = ledger.SettlementConfirmed
			record.TransactionHash = hash
			record.LastError = ""
		}
		if err := w.Repository.Save(ctx, record, w.WorkerID); err != nil {
			return err
		}
	}
	return nil
}