package query

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"queryorchestration/internal/database"
	"queryorchestration/internal/database/repository"
	resultprocessor "queryorchestration/internal/query/result/processor"
	contextfull "queryorchestration/internal/query/types/contextFull"
	jsonextractor "queryorchestration/internal/query/types/jsonExtractor"
	"queryorchestration/internal/validation"

	"github.com/google/uuid"
)

func (s *Service) Update(ctx context.Context, entity *resultprocessor.Update) error {
	current, err := s.Get(ctx, entity.ID)
	if err != nil {
		return err
	}

	err = s.normalizeUpdate(ctx, current, entity)
	if err != nil {
		return err
	}

	err = s.submitUpdate(ctx, current, entity)
	if err != nil {
		return err
	}

	return nil
}

func (s *Service) normalizeUpdateRequiredQueryIDs(ctx context.Context, current *Query, entity RequiredQueryIDs) error {
	err := s.NormalizeQueryIDs(ctx, entity)
	if err != nil {
		return err
	}

	if entity.GetRequiredQueryIDs() == nil {
		return nil
	}

	createsloop, err := s.cfg.GetDBQueries().IsQueryInDependencyTree(ctx, &repository.IsQueryInDependencyTreeParams{
		Requiredqueryid: database.MustToDBUUID(current.ID),
		ID:              database.MustToDBUUIDArray(*entity.GetRequiredQueryIDs()),
	})
	if err != nil {
		return err
	} else if createsloop {
		return errors.New("required ids create a loop")
	}

	addIDs := getSetDifference(entity.GetRequiredQueryIDs(), current.RequiredQueryIDs)
	removeIDs := getSetDifference(current.RequiredQueryIDs, entity.GetRequiredQueryIDs())

	if len(addIDs) == 0 && len(removeIDs) == 0 {
		entity.SetRequiredQueryIDs(nil)
	}

	return nil
}

func (s *Service) normalizeUpdate(ctx context.Context, current *Query, entity *resultprocessor.Update) error {
	err := s.normalizeActiveVersion(current, entity)
	if err != nil {
		return err
	}

	err = s.normalizeUpdateRequiredQueryIDs(ctx, current, entity)
	if err != nil {
		return err
	}

	err = s.normalizeConfig(entity)
	if err != nil {
		return err
	}

	activeVersionName, err := validation.GetFieldName(entity, entity.ActiveVersion)
	if err != nil {
		return err
	}

	if (entity.ActiveVersion == nil || *entity.ActiveVersion == current.LatestVersion+1) &&
		validation.AreAllPointersNilExcept(entity, activeVersionName) {
		return errors.New("no changes")
	}

	validator, err := s.getUpdator(current.Type)
	if err != nil {
		return err
	}

	err = validator.Validate(ctx, ParseQuery(current), entity)
	if err != nil {
		return err
	}

	return nil
}

func (s *Service) submitUpdate(ctx context.Context, current *Query, entity *resultprocessor.Update) error {
	err := s.cfg.ExecuteDBTransaction(ctx, func(ctx context.Context, q *repository.Queries) error {
		latestVersion := current.LatestVersion + 1
		id := database.MustToDBUUID(entity.ID)

		addIDs := getSetDifference(entity.RequiredQueryIDs, current.RequiredQueryIDs)
		for _, qID := range addIDs {
			err := q.AddRequiredQuery(ctx, &repository.AddRequiredQueryParams{
				Queryid:         id,
				Requiredqueryid: database.MustToDBUUID(qID),
				Addedversion:    latestVersion,
			})
			if err != nil {
				return err
			}
		}

		removeIDs := getSetDifference(current.RequiredQueryIDs, entity.RequiredQueryIDs)
		for _, qID := range removeIDs {
			err := q.RemoveRequiredQuery(ctx, &repository.RemoveRequiredQueryParams{
				Queryid:         id,
				Requiredqueryid: database.MustToDBUUID(qID),
				Removedversion:  &latestVersion,
			})
			if err != nil {
				return err
			}
		}

		if entity.Config != nil && *entity.Config != "" {
			err := q.RemoveQueryConfig(ctx, &repository.RemoveQueryConfigParams{
				Queryid:        id,
				Removedversion: &latestVersion,
			})
			if err != nil {
				return err
			}

			err = q.AddQueryConfig(ctx, &repository.AddQueryConfigParams{
				Queryid:      id,
				Config:       []byte(*entity.Config),
				Addedversion: latestVersion,
			})
			if err != nil {
				return err
			}
		}

		activeVersion := entity.ActiveVersion
		if activeVersion == nil {
			activeVersion = &current.ActiveVersion
		}

		err := q.UpdateQuery(ctx, &repository.UpdateQueryParams{
			Latestversion: latestVersion,
			Activeversion: *activeVersion,
			ID:            id,
		})
		if err != nil {
			return err
		}

		slog.Debug("query updated", "update", *entity)

		return nil
	})
	if err != nil {
		return err
	}

	return nil
}

func getSetDifference(setA *[]uuid.UUID, setB *[]uuid.UUID) []uuid.UUID {
	if setA == nil {
		return []uuid.UUID{}
	} else if setB == nil {
		return *setA
	}

	diff := []uuid.UUID{}
	for _, q := range *setA {
		isFound := false
		for _, eq := range *setB {
			if q == eq {
				isFound = true
				break
			}
		}
		if !isFound {
			diff = append(diff, q)
		}
	}

	return diff
}

func (s *Service) getUpdator(qType resultprocessor.Type) (resultprocessor.Updator, error) {
	switch qType {
	case resultprocessor.TypeJsonExtractor:
		return jsonextractor.NewUpdator(), nil
	case resultprocessor.TypeContextFull:
		return contextfull.NewUpdator(), nil
	default:
		return nil, fmt.Errorf("attempting to process invalid query type")
	}
}

func ParseQuery(q *Query) *resultprocessor.Query {
	return &resultprocessor.Query{
		ID:               q.ID,
		Type:             q.Type,
		Version:          q.ActiveVersion,
		RequiredQueryIDs: q.RequiredQueryIDs,
		Config:           q.Config,
	}
}