package verification

import (
	"context"

	"git.sendico.io/tech/sxchnge/bff/pkg/db/repository"
	"git.sendico.io/tech/sxchnge/bff/pkg/merrors"
	"git.sendico.io/tech/sxchnge/bff/pkg/model"
	"git.sendico.io/tech/sxchnge/bff/pkg/mutil/mzap"
	"go.uber.org/zap"
)

func (db *verificationDB) validateConsumeToken(
	scope consumeScope,
	token *model.VerificationToken,
) error {
	if token.UsedAt != nil {
		db.Logger.Debug("Verification consume static check failed: token already used",
			scope.tokenLogFields(token)...,
		)
		return ErorrTokenAlreadyUsed()
	}
	if !token.ExpiresAt.After(scope.now) {
		db.Logger.Debug("Verification consume static check failed: token expired",
			scope.tokenLogFields(token, zap.Time("now_utc", scope.now))...,
		)
		return ErorrTokenExpired()
	}
	if token.MaxRetries != nil && token.Attempts >= *token.MaxRetries {
		db.Logger.Debug("Verification consume static check failed: attempts exceeded",
			scope.tokenLogFields(token)...,
		)
		return ErrorTokenAttemptsExceeded()
	}

	db.Logger.Debug("Verification consume static checks passed",
		scope.tokenLogFields(token)...,
	)
	return nil
}

func (db *verificationDB) consumeMatchedToken(
	ctx context.Context,
	scope consumeScope,
	token *model.VerificationToken,
) (*model.VerificationToken, error) {
	db.Logger.Debug("Verification consume atomic update attempt",
		scope.logFields(mzap.StorableRef(token))...,
	)

	updated, err := db.PatchMany(
		ctx,
		scope.consumeFilter(token),
		repository.Patch().Set(repository.Field("usedAt"), scope.now),
	)
	if err != nil {
		db.Logger.Warn("Verification consume atomic update failed",
			scope.logFields(mzap.StorableRef(token), zap.Error(err))...,
		)
		return nil, err
	}
	db.Logger.Debug("Verification consume atomic update result",
		scope.logFields(mzap.StorableRef(token), zap.Int("updated_count", updated))...,
	)

	if updated == 1 {
		token.UsedAt = &scope.now
		db.Logger.Debug("Verification consume succeeded", scope.tokenLogFields(token)...)
		return token, nil
	}

	db.incrementConsumeAttemptsAfterAtomicMiss(ctx, scope, token)
	return nil, db.consumeMissError(ctx, scope, token)
}

func (db *verificationDB) incrementConsumeAttemptsAfterAtomicMiss(
	ctx context.Context,
	scope consumeScope,
	token *model.VerificationToken,
) {
	incremented, err := db.PatchMany(
		ctx,
		repository.IDFilter(token.ID),
		repository.Patch().Inc(repository.Field("attempts"), 1),
	)
	if err != nil {
		db.Logger.Warn("Verification consume failed to increment attempts after atomic update miss",
			scope.logFields(mzap.StorableRef(token), zap.Error(err))...,
		)
		return
	}

	db.Logger.Debug("Verification consume incremented attempts after atomic update miss",
		scope.logFields(
			mzap.StorableRef(token),
			zap.Int("updated_count", incremented),
			zap.String("transaction_note", "this update occurs inside transaction and may roll back depending on returned error"),
		)...,
	)
}

func (db *verificationDB) consumeMissError(
	ctx context.Context,
	scope consumeScope,
	token *model.VerificationToken,
) error {
	var fresh model.VerificationToken
	if err := db.FindOne(ctx, repository.IDFilter(token.ID), &fresh); err != nil {
		db.Logger.Warn("Verification consume failed to re-check token state",
			scope.logFields(mzap.StorableRef(token), zap.Error(err))...,
		)
		return merrors.Internal("failed to re-check token state")
	}
	db.Logger.Debug("Verification consume re-checked token state after atomic miss",
		scope.tokenLogFields(&fresh, mzap.StorableRef(token))...,
	)

	if fresh.UsedAt != nil {
		db.Logger.Debug("Verification consume final decision: already used after re-check",
			scope.logFields(mzap.StorableRef(token))...,
		)
		return ErorrTokenAlreadyUsed()
	}
	if !fresh.ExpiresAt.After(scope.now) {
		db.Logger.Debug("Verification consume final decision: expired after re-check",
			scope.logFields(
				mzap.StorableRef(token),
				zap.Time("now_utc", scope.now),
				zap.Time("token_expires_at", fresh.ExpiresAt),
			)...,
		)
		return ErorrTokenExpired()
	}
	if fresh.MaxRetries != nil && fresh.Attempts >= *fresh.MaxRetries {
		db.Logger.Debug("Verification consume final decision: attempts exceeded after re-check",
			scope.logFields(
				mzap.StorableRef(token),
				zap.Int("token_attempts", fresh.Attempts),
				zap.Int("token_max_retries", *fresh.MaxRetries),
			)...,
		)
		return ErrorTokenAttemptsExceeded()
	}

	db.Logger.Debug("Verification consume final decision: token not found after re-check",
		scope.logFields(mzap.StorableRef(token))...,
	)
	return ErorrTokenNotFound()
}