# Check that a field is a JsonObject
#
# ~~~
# var validator = new ObjectValidator
# validator.add new RequiredField("id", required = true)
# var user_val = new ObjectField("user")
# user_val.add new RequiredField("id", required = true)
# user_val.add new StringField("login", min_size=4)
# validator.add user_val
# assert not validator.validate("""{ "id": "", "user": { "login": "Alex" } }""")
# assert validator.validate("""{ "id": "", "user": { "id": "foo", "login": "Alex" } }""")
# ~~~
class ObjectField
	super RequiredField
	super ObjectValidator

	redef var validation = new ValidationResult

	redef fun validate_field(v, obj) do
		if not super then return false
		var val = obj.get_or_null(field)
		if val == null then
			if required == null or required == true then
				v.validation.add_error(field, "Expected Object got `null`")
				return false
			else
				return true
			end
		end
		var res = validate_json(val)
		for field, messages in validation.errors do
			for message in messages do v.validation.add_error("{self.field}.{field}", message)
		end
		return res
	end
end