//   Copyright 2016 DigitalOcean
//
//   Licensed under the Apache License, Version 2.0 (the "License");
//   you may not use this file except in compliance with the License.
//   You may obtain a copy of the License at
//
//       http://www.apache.org/licenses/LICENSE-2.0
//
//   Unless required by applicable law or agreed to in writing, software
//   distributed under the License is distributed on an "AS IS" BASIS,
//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//   See the License for the specific language governing permissions and
//   limitations under the License.

package collectors

import "github.com/ceph/go-ceph/rados"

// Conn interface implements only necessary methods that are used
// in this repository of *rados.Conn. This keeps rest of the implementation
// clean and *rados.Conn doesn't need to show up everywhere (it being
// more of an implementation detail in reality). Also it makes mocking
// easier for unit-testing the collectors.
type Conn interface {
	ReadDefaultConfigFile() error
	Connect() error
	Shutdown()
	MonCommand([]byte) ([]byte, string, error)
}

// Verify that *rados.Conn implements Conn correctly.
var _ Conn = &rados.Conn{}

// NoopConn is the stub we use for mocking rados Conn. Unit testing
// each individual collectors becomes a lot easier after that.
type NoopConn struct {
	output string
}

// The stub we use for testing should also satisfy the interface properties.
var _ Conn = &NoopConn{}

// NewNoopConn returns an instance of *NoopConn. The string that we want
// outputted at the end of the command we issue to ceph, should be
// specified in the only input parameter.
func NewNoopConn(output string) *NoopConn {
	return &NoopConn{output}
}

// ReadDefaultConfigFile does not need to return an error. It satisfies
// rados.Conn's function with the same prototype.
func (n *NoopConn) ReadDefaultConfigFile() error {
	return nil
}

// Connect does not need to return an error. It satisfies
// rados.Conn's function with the same prototype.
func (n *NoopConn) Connect() error {
	return nil
}

// Shutdown satisfies rados.Conn's function prototype.
func (n *NoopConn) Shutdown() {}

// MonCommand returns the provided output string to NoopConn as is, making
// it seem like it actually ran something and produced that string as a result.
func (n *NoopConn) MonCommand(_ []byte) ([]byte, string, error) {
	return []byte(n.output), "", nil
}