# A MongoDb database.
#
# Database are automatically created on the MongoDB server upon insertion of the
# first document into a collection.
# There is no need to create a database manually.
class MongoDb
	super FinalizableOnce

	# `MongoClient` used to load this database.
	var client: MongoClient

	# The database name.
	var name: String

	private var native: NativeMongoDb is noinit

	init do native = new NativeMongoDb(client.native, name.to_cstring)

	# Lists available collection names.
	#
	# Returns `null` if an error occured. See `Sys::last_mongoc_error`.
	#
	# ~~~
	# var client = new MongoClient("mongodb://mongo:27017/")
	# var db_suffix = "NIT_TESTING_ID".environ
	# var db_name = "test_{db_suffix}"
	# var db = client.database(db_name)
	# db.collection("test").insert(new JsonObject)
	# assert db.collection_names.has("test")
	# ~~~
	fun collection_names: Array[String] do
		var res = new Array[String]
		var nas = native.collection_names
		if nas == null then return res
		var i = 0
		var name = nas[i]
		while not name.address_is_null do
			res.add name.to_s
			name.free
			i += 1
			name = nas[i]
		end
		return res
	end

	# Loads or creates a collection by its `name`.
	#
	# ~~~
	# var client = new MongoClient("mongodb://mongo:27017/")
	# var db_suffix = "NIT_TESTING_ID".environ
	# var db_name = "test_{db_suffix}"
	# var db = client.database(db_name)
	# var col = db.collection("test")
	# assert col.name == "test"
	# ~~~
	fun collection(name: String): MongoCollection do
		return new MongoCollection(self, name)
	end

	# Checks if a collection named `name` exists.
	#
	# ~~~
	# var client = new MongoClient("mongodb://mongo:27017/")
	# var db_suffix = "NIT_TESTING_ID".environ
	# var db_name = "test_{db_suffix}"
	# var db = client.database(db_name)
	# assert not db.has_collection("qwerty")
	# ~~~
	fun has_collection(name: String): Bool do
		# TODO handle error
		return native.has_collection(name.to_cstring)
	end

	# Drop `self`, returns false if an error occured.
	fun drop: Bool do return native.drop

	redef fun finalize_once do native.destroy
end