package verificationimp

import (
	"context"
	"errors"
	"time"

	"github.com/tech/sendico/pkg/db/repository"
	"github.com/tech/sendico/pkg/db/verification"
	"github.com/tech/sendico/pkg/merrors"
	"github.com/tech/sendico/pkg/model"
	"go.uber.org/zap"
)

func (db *verificationDB) Consume(
	ct context.Context,
	rawToken string,
) (*model.VerificationToken, error) {

	hash := tokenHash(rawToken)
	now := time.Now().UTC()

	// 1) Find token by hash (do NOT filter by usedAt/expiresAt here),
	// otherwise you can't distinguish "used/expired" from "not found".
	filter := repository.Query().And(
		repository.Filter("verifyTokenHash", hash),
	)

	t, e := db.tf.CreateTransaction().Execute(
		ct,
		func(ctx context.Context) (any, error) {
			var existing model.VerificationToken
			if err := db.DBImp.FindOne(ctx, filter, &existing); err != nil {
				if errors.Is(err, merrors.ErrNoData) {
					db.Logger.Debug("Token hash not found", zap.Error(err), zap.String("hash", hash))
					return nil, verification.ErorrTokenNotFound()
				}
				db.Logger.Warn("Failed to check token", zap.Error(err), zap.String("hash", hash))
				return nil, err
			}

			// 2) Semantic checks
			if existing.UsedAt != nil {
				db.Logger.Debug(
					"Token has already been used",
					zap.String("hash", hash),
					zap.Time("used_at", *existing.UsedAt),
				)
				return nil, verification.ErorrTokenAlreadyUsed()
			}

			if !existing.ExpiresAt.After(now) { // includes equal time edge-case
				db.Logger.Debug(
					"Token has already expired",
					zap.String("hash", hash),
					zap.Time("expired_at", existing.ExpiresAt),
				)
				return nil, verification.ErorrTokenExpired()
			}

			// 3) Mark as used
			existing.UsedAt = &now
			if err := db.DBImp.Update(ctx, &existing); err != nil {
				db.Logger.Warn("Failed to consume token", zap.Error(err), zap.String("hash", hash))
				return nil, err
			}

			return &existing, nil
		},
	)
	if e != nil {
		return nil, e
	}

	res, ok := t.(*model.VerificationToken)
	if !ok {
		return nil, merrors.Internal("unexpected token type")
	}

	return res, nil
}