# Wrapper for `mongoc_collection_t`.
#
# `mongoc_collection_t` provides access to a MongoDB collection.
# This handle is useful for actions for most CRUD operations,
# I.e. insert, update, delete, find, etc.
#
# It is an error to call `mongoc_collection_destroy()` on a collection that has
# operations pending.
# It is required that you release `mongoc_cursor_t` structures before calling
# `mongoc_collection_destroy()`.
#
# See [`mongoc_collection_t`](http://api.mongodb.org/c/current/mongoc_collection_t.html).
extern class NativeMongoCollection `{ mongoc_collection_t * `}

	# Wrapper for `mongoc_client_get_collection()`.
	#
	# Get a newly allocated `mongoc_collection_t` for the collection named
	# `collection` in the database named `db`.
	#
	# Collections are automatically created on the MongoDB server upon insertion
	# of the first document.
	# There is no need to create a collection manually.
	new(client: NativeMongoClient, db, collection: CString) `{
		return mongoc_client_get_collection(client, db, collection);
	`}

	# Wrapper for `mongoc_collection_insert()`.
	#
	# This function shall insert `document` into the collection.
	# If no `_id` element is found in document, then a `bson_oid_t` will be
	# generated locally and added to the document.
	#
	# You can retrieve a generated `_id` from `sys.last_mongoc_id`.
	fun insert(document: NativeBSON): Bool import set_mongoc_error, set_mongoc_last_id `{
		bson_oid_t oid;
		if(!bson_has_field(document, "_id")) {
			bson_oid_init (&oid, NULL);
			BSON_APPEND_OID (document, "_id", &oid);
			NativeMongoCollection_set_mongoc_last_id(self, &oid);
		}
		bson_error_t error;
		if(!mongoc_collection_insert(self, MONGOC_INSERT_NONE, document, NULL, &error)) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return false;
		}
		return true;
	`}

	# Wrapper for `mongoc_collection_save()`.
	#
	# This function shall save a document into the collection.
	# If the document has an `_id` field it will be updated.
	# Otherwise it will be inserted.
	#
	# You can retrieve a generated `_id` from `sys.last_mongoc_id`.
	fun save(document: NativeBSON): Bool import set_mongoc_error, set_mongoc_last_id `{
		bson_oid_t oid;
		if(!bson_has_field(document, "_id")) {
			bson_oid_init (&oid, NULL);
			BSON_APPEND_OID (document, "_id", &oid);
			NativeMongoCollection_set_mongoc_last_id(self, &oid);
		}
		bson_error_t error;
		if(!mongoc_collection_save(self, document, NULL, &error)) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return false;
		}
		return true;
	`}

	# Wrapper for `mongoc_collection_remove(MONGOC_REMOVE_SINGLE_REMOVE)`.
	#
	# This function shall remove the first document in the collection that matches
	# `selector`.
	# The bson selector is not validated, simply passed along as appropriate to the server.
	fun remove(selector: NativeBSON): Bool import set_mongoc_error `{
		bson_error_t error;
		if(!mongoc_collection_remove(self, MONGOC_REMOVE_SINGLE_REMOVE, selector, NULL, &error)) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return false;
		}
		return true;
	`}

	# Wrapper for `mongoc_collection_remove(MONGOC_REMOVE_NONE)`.
	#
	# This function shall remove documents in the collection that match `selector`.
	fun remove_all(selector: NativeBSON): Bool import set_mongoc_error `{
		bson_error_t error;
		if(!mongoc_collection_remove(self, MONGOC_REMOVE_NONE, selector, NULL, &error)) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return false;
		}
		return true;
	`}

	# Wrapper for `mongoc_collection_update(MONGOC_UPDATE_NONE)`.
	#
	# This function shall update the first document in the collection that
	# matches `selector`.
	fun update(selector, update: NativeBSON): Bool import set_mongoc_error `{
		bson_error_t error;
		if(!mongoc_collection_update(self, MONGOC_UPDATE_NONE, selector, update, NULL, &error)) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return false;
		}
		return true;
	`}

	# Wrapper for `mongoc_collection_update(MONGOC_UPDATE_MULTI_UPDATE)`.
	#
	# This function shall update documents in the collection that match `selector`.
	fun update_all(selector, update: NativeBSON): Bool import set_mongoc_error `{
		bson_error_t error;
		if(!mongoc_collection_update(self, MONGOC_UPDATE_MULTI_UPDATE, selector, update, NULL, &error)) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return false;
		}
		return true;
	`}

	# Wrapper for `mongoc_collection_count()`.
	#
	# This function shall execute a count `query` on the underlying collection.
	fun count(query: NativeBSON): Int import set_mongoc_error `{
		bson_error_t error;
		int64_t count = mongoc_collection_count(self, MONGOC_QUERY_NONE, query, 0, 0, NULL, &error);
		if(count < 0) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return -1;
		}
		return count;
	`}

	# Wrapper for `mongoc_collection_find()`.
	#
	# This function shall execute a `query` on the underlying collection.
	#
	# If no options are necessary, `query` can simply contain a query such as `{a:1}`.
	#
	# If you would like to specify options such as a sort order,
	# the query must be placed inside of `{"$query": {}}`.
	fun find(query: NativeBSON, skip, limit: Int): nullable NativeMongoCursor import
		NativeMongoCursor.as nullable, set_mongoc_error `{
		bson_error_t error;
		mongoc_cursor_t	*cursor;
		cursor = mongoc_collection_find(self, MONGOC_QUERY_NONE, skip, limit, 0, query, NULL, NULL);
		if (mongoc_cursor_error(cursor, &error)) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return null_NativeMongoCursor();
		}
		return NativeMongoCursor_as_nullable(cursor);
	`}

	# Wrapper for `mongoc_collection_aggregate()`.
	#
	# This function shall execute an aggregation `pipeline` on the underlying collection.
	#
	# The `pipeline` parameter should contain a field named `pipeline` containing
	# a BSON array of pipeline stages.
	fun aggregate(pipeline: NativeBSON): nullable NativeMongoCursor import
		NativeMongoCursor.as nullable, set_mongoc_error `{
		bson_error_t error;
		mongoc_cursor_t	*cursor;
		cursor = mongoc_collection_aggregate(self, MONGOC_QUERY_NONE, pipeline, NULL, NULL);
		if (mongoc_cursor_error(cursor, &error)) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return null_NativeMongoCursor();
		}
		return NativeMongoCursor_as_nullable(cursor);
	`}

	# Wrapper for `mongoc_collection_stats()`.
	#
	# This function is a helper to retrieve statistics about the collection.
	fun stats: nullable NativeBSON import set_mongoc_error, NativeBSON.as nullable `{
		bson_error_t error;
		bson_t *reply = bson_new();
		if(!mongoc_collection_stats(self, NULL, reply, &error)){
			NativeMongoCollection_set_mongoc_error(self, &error);
			return null_NativeBSON();
		}
		return NativeBSON_as_nullable(reply);
	`}

	# Wrapper for `mongoc_collection_drop()`.
	#
	# This function requests that the `collection` be dropped,
	# including all indexes associated with the collection.
	fun drop: Bool import set_mongoc_error `{
		bson_error_t error;
		if(!mongoc_collection_drop(self, &error)) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return false;
		}
		return true;
	`}

	# Wrapper for `mongoc_collection_rename()`.
	#
	# This function is a helper to rename an existing collection on a MongoDB server.
	# The name of the collection will also be updated internally so it is safe
	# to continue using this collection after the rename.
	# Additional operations will occur on renamed collection.
	fun rename(new_database, new_name: CString): Bool `{
		bson_error_t error;
		if(!mongoc_collection_rename(self, new_database, new_name, false, &error)){
			NativeMongoCollection_set_mongoc_error(self, &error);
			return false;
		}
		return true;
	`}

	# Wrapper for `mongoc_collection_destroy()`.
	#
	# This instance should not be used beyond this point!
	fun destroy `{ mongoc_collection_destroy(self); `}

	# Utility method to set `Sys.last_mongoc_last_id`.
	fun set_mongoc_last_id(id: BSONObjectId) do sys.last_mongoc_id = id

	# Utility method to set `Sys.last_mongoc_error`.
	fun set_mongoc_error(err: BSONError) do sys.last_mongoc_error = err
end