/*
Copyright 2016 The Kubernetes Authors All rights reserved.

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 kube

import (
	"fmt"
	"io"

	"k8s.io/kubernetes/pkg/api"
	"k8s.io/kubernetes/pkg/api/errors"
	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
	"k8s.io/kubernetes/pkg/kubectl/resource"
)

// Client represents a client capable of communicating with the Kubernetes API.
type Client struct {
	*cmdutil.Factory
}

// New create a new Client
func New(config clientcmd.ClientConfig) *Client {
	return &Client{
		Factory: cmdutil.NewFactory(config),
	}
}

// ResourceActorFunc performs an action on a signle resource.
type ResourceActorFunc func(*resource.Info) error

// Create creates kubernetes resources from an io.reader
//
// Namespace will set the namespace
func (c *Client) Create(namespace string, reader io.Reader) error {
	if err := c.ensureNamespace(namespace); err != nil {
		return err
	}
	return perform(c, namespace, reader, createResource)
}

// Delete deletes kubernetes resources from an io.reader
//
// Namespace will set the namespace
func (c *Client) Delete(namespace string, reader io.Reader) error {
	return perform(c, namespace, reader, deleteResource)
}

const includeThirdPartyAPIs = false

func perform(c *Client, namespace string, reader io.Reader, fn ResourceActorFunc) error {
	r := c.NewBuilder(includeThirdPartyAPIs).
		ContinueOnError().
		NamespaceParam(namespace).
		DefaultNamespace().
		Stream(reader, "").
		Flatten().
		Do()

	if r.Err() != nil {
		return r.Err()
	}

	count := 0
	err := r.Visit(func(info *resource.Info, err error) error {
		if err != nil {
			return err
		}
		err = fn(info)

		if err == nil {
			count++
		}
		return err
	})

	if err != nil {
		return err
	}
	if count == 0 {
		return fmt.Errorf("no objects passed to create")
	}
	return nil
}

func createResource(info *resource.Info) error {
	_, err := resource.NewHelper(info.Client, info.Mapping).Create(info.Namespace, true, info.Object)
	return err
}

func deleteResource(info *resource.Info) error {
	return resource.NewHelper(info.Client, info.Mapping).Delete(info.Namespace, info.Name)
}

func (c *Client) ensureNamespace(namespace string) error {
	client, err := c.Client()
	if err != nil {
		return err
	}

	ns := &api.Namespace{}
	ns.Name = namespace
	_, err = client.Namespaces().Create(ns)
	if err != nil && !errors.IsAlreadyExists(err) {
		return err
	}
	return nil
}