package leaf

var (
	FilterAll = FilterDocument{}
)

const (
	OperatorEq     Operator = "$eq"
	OperatorNe     Operator = "$ne"
	OperatorGt     Operator = "$gt"
	OperatorGte    Operator = "$gte"
	OperatorLt     Operator = "$lt"
	OperatorLte    Operator = "$lte"
	OperatorIn     Operator = "$in"
	OperatorNin    Operator = "$nin"
	OperatorExists Operator = "$exists"
	OperatorRegex  Operator = "$regex"
)

type M map[Operator]any
type Operator string
type FilterDocument map[string]M

func Eq[T any](field string, value T) FilterDocument {
	return createSelector(field, OperatorEq, value)
}

func Ne[T any](field string, value T) FilterDocument {
	return createSelector(field, OperatorNe, value)
}

func Gt[T any](field string, value T) FilterDocument {
	return createSelector(field, OperatorGt, value)
}

func Gte[T any](field string, value T) FilterDocument {
	return createSelector(field, OperatorGte, value)
}

func Lt[T any](field string, value T) FilterDocument {
	return createSelector(field, OperatorLt, value)
}

func Lte[T any](field string, value T) FilterDocument {
	return createSelector(field, OperatorLte, value)
}

func In[T any](field string, value []T) FilterDocument {
	return createSelector(field, OperatorIn, value)
}

func Nin[T any](field string, value []T) FilterDocument {
	return createSelector(field, OperatorNin, value)
}

func Exists(field string, value bool) FilterDocument {
	return createSelector(field, OperatorExists, value)
}

func Regex(field string, value string) FilterDocument {
	return createSelector(field, OperatorRegex, value)
}

func createSelector(field string, operator Operator, value any) FilterDocument {
	return FilterDocument{field: M{operator: value}}
}

func Filter(docs ...FilterDocument) FilterDocument {
	query := FilterDocument{}
	for _, doc := range docs {
		for field, operators := range doc {
			if _, ok := query[field]; !ok {
				query[field] = operators
				continue
			}

			for op, value := range operators {
				query[field][op] = value
			}
		}
	}

	return query
}