# A Repository is an object that can store serialized instances.
#
# Repository is the base class of all kind of persistance processes. It offers
# the base CRUD services to save (add/update), find and delete instances.
#
# Instances are stored in their serialized form. See the `serialization` package
# for more documentation.
interface Repository[E: Serializable]

	# Kind of queries accepted
	#
	# Can be redefined to accept more precise queries depending on the backend used.
	type QUERY: RepositoryQuery

	# Find an instance by it's `id`
	#
	# `id` is an abstract thing at this stage
	# TODO maybe introduce the `PrimaryKey` concept?
	fun find_by_id(id: String): nullable E is abstract

	# Find an instance based on `query`
	fun find(query: QUERY): nullable E is abstract

	# Find all instances based on `query`
	#
	# Using `query` == null will retrieve all the document in the repository.
	fun find_all(query: nullable QUERY, skip, limit: nullable Int): Array[E] is abstract

	# Count instances that matches `query`
	fun count(query: nullable QUERY): Int is abstract

	# Save an `instance`
	fun save(instance: E): Bool is abstract

	# Remove the instance with `id`
	fun remove_by_id(id: String): Bool is abstract

	# Remove the instance based on `query`
	fun remove(query: nullable QUERY): Bool is abstract

	# Remove all the instances matching on `query`
	fun remove_all(query: nullable QUERY): Bool is abstract

	# Remove all instances
	fun clear: Bool is abstract

	# Serialize an `instance` to a String.
	fun serialize(instance: nullable E): nullable String is abstract

	# Deserialize a `string` to an instance.
	fun deserialize(string: nullable String): nullable E is abstract
end