// Copyright 2014 Google Inc. 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 container contains a Google Container Engine client.
//
// For more information about the API,
// see https://cloud.google.com/container-engine/docs
//
// Authentication
//
// See examples of authorization and authentication at
// https://godoc.org/cloud.google.com/go#pkg-examples.
package container // import "cloud.google.com/go/container"

import (
	"errors"
	"fmt"
	"time"

	"golang.org/x/net/context"
	raw "google.golang.org/api/container/v1"
	"google.golang.org/api/option"
	"google.golang.org/api/transport"
)

type Type string

const (
	TypeCreate = Type("createCluster")
	TypeDelete = Type("deleteCluster")
)

type Status string

const (
	StatusDone         = Status("done")
	StatusPending      = Status("pending")
	StatusRunning      = Status("running")
	StatusError        = Status("error")
	StatusProvisioning = Status("provisioning")
	StatusStopping     = Status("stopping")
)

const prodAddr = "https://container.googleapis.com/"
const userAgent = "gcloud-golang-container/20151008"

// Client is a Google Container Engine client, which may be used to manage
// clusters with a project.  It must be constructed via NewClient.
type Client struct {
	projectID string
	svc       *raw.Service
}

// NewClient creates a new Google Container Engine client.
func NewClient(ctx context.Context, projectID string, opts ...option.ClientOption) (*Client, error) {
	o := []option.ClientOption{
		option.WithEndpoint(prodAddr),
		option.WithScopes(raw.CloudPlatformScope),
		option.WithUserAgent(userAgent),
	}
	o = append(o, opts...)
	httpClient, endpoint, err := transport.NewHTTPClient(ctx, o...)
	if err != nil {
		return nil, fmt.Errorf("dialing: %v", err)
	}

	svc, err := raw.New(httpClient)
	if err != nil {
		return nil, fmt.Errorf("constructing container client: %v", err)
	}
	svc.BasePath = endpoint

	c := &Client{
		projectID: projectID,
		svc:       svc,
	}

	return c, nil
}

// Resource is a Google Container Engine cluster resource.
type Resource struct {
	// Name is the name of this cluster. The name must be unique
	// within this project and zone, and can be up to 40 characters.
	Name string

	// Description is the description of the cluster. Optional.
	Description string

	// Zone is the Google Compute Engine zone in which the cluster resides.
	Zone string

	// Status is the current status of the cluster. It could either be
	// StatusError, StatusProvisioning, StatusRunning or StatusStopping.
	Status Status

	// Num is the number of the nodes in this cluster resource.
	Num int64

	// APIVersion is the version of the Kubernetes master and kubelets running
	// in this cluster. Allowed value is 0.4.2, or leave blank to
	// pick up the latest stable release.
	APIVersion string

	// Endpoint is the IP address of this cluster's Kubernetes master.
	// The endpoint can be accessed at https://username:password@endpoint/.
	// See Username and Password fields for the username and password information.
	Endpoint string

	// Username is the username to use when accessing the Kubernetes master endpoint.
	Username string

	// Password is the password to use when accessing the Kubernetes master endpoint.
	Password string

	// ContainerIPv4CIDR is the IP addresses of the container pods in
	// this cluster, in CIDR notation (e.g. 1.2.3.4/29).
	ContainerIPv4CIDR string

	// ServicesIPv4CIDR is the IP addresses of the Kubernetes services in this
	// cluster, in CIDR notation (e.g. 1.2.3.4/29). Service addresses are
	// always in the 10.0.0.0/16 range.
	ServicesIPv4CIDR string

	// MachineType is a Google Compute Engine machine type (e.g. n1-standard-1).
	// If none set, the default type is used while creating a new cluster.
	MachineType string

	// This field is ignored. It was removed from the underlying container API in v1.
	SourceImage string

	// Created is the creation time of this cluster.
	Created time.Time
}

func resourceFromRaw(c *raw.Cluster) *Resource {
	if c == nil {
		return nil
	}
	r := &Resource{
		Name:              c.Name,
		Description:       c.Description,
		Zone:              c.Zone,
		Status:            Status(c.Status),
		Num:               c.InitialNodeCount,
		APIVersion:        c.InitialClusterVersion,
		Endpoint:          c.Endpoint,
		Username:          c.MasterAuth.Username,
		Password:          c.MasterAuth.Password,
		ContainerIPv4CIDR: c.ClusterIpv4Cidr,
		ServicesIPv4CIDR:  c.ServicesIpv4Cidr,
		MachineType:       c.NodeConfig.MachineType,
	}
	r.Created, _ = time.Parse(time.RFC3339, c.CreateTime)
	return r
}

func resourcesFromRaw(c []*raw.Cluster) []*Resource {
	r := make([]*Resource, len(c))
	for i, val := range c {
		r[i] = resourceFromRaw(val)
	}
	return r
}

// Op represents a Google Container Engine API operation.
type Op struct {
	// Name is the name of the operation.
	Name string

	// Zone is the Google Compute Engine zone.
	Zone string

	// This field is ignored. It was removed from the underlying container API in v1.
	TargetURL string

	// Type is the operation type. It could be either be TypeCreate or TypeDelete.
	Type Type

	// Status is the current status of this operation. It could be either
	// OpDone or OpPending.
	Status Status
}

func opFromRaw(o *raw.Operation) *Op {
	if o == nil {
		return nil
	}
	return &Op{
		Name:   o.Name,
		Zone:   o.Zone,
		Type:   Type(o.OperationType),
		Status: Status(o.Status),
	}
}

func opsFromRaw(o []*raw.Operation) []*Op {
	ops := make([]*Op, len(o))
	for i, val := range o {
		ops[i] = opFromRaw(val)
	}
	return ops
}

// Clusters returns a list of cluster resources from the specified zone.
// If no zone is specified, it returns all clusters under the user project.
func (c *Client) Clusters(ctx context.Context, zone string) ([]*Resource, error) {
	if zone == "" {
		zone = "-"
	}
	resp, err := c.svc.Projects.Zones.Clusters.List(c.projectID, zone).Do()
	if err != nil {
		return nil, err
	}
	return resourcesFromRaw(resp.Clusters), nil
}

// Cluster returns metadata about the specified cluster.
func (c *Client) Cluster(ctx context.Context, zone, name string) (*Resource, error) {
	resp, err := c.svc.Projects.Zones.Clusters.Get(c.projectID, zone, name).Do()
	if err != nil {
		return nil, err
	}
	return resourceFromRaw(resp), nil
}

// CreateCluster creates a new cluster with the provided metadata
// in the specified zone.
func (c *Client) CreateCluster(ctx context.Context, zone string, resource *Resource) (*Resource, error) {
	panic("not implemented")
}

// DeleteCluster deletes a cluster.
func (c *Client) DeleteCluster(ctx context.Context, zone, name string) error {
	_, err := c.svc.Projects.Zones.Clusters.Delete(c.projectID, zone, name).Do()
	return err
}

// Operations returns a list of operations from the specified zone.
// If no zone is specified, it looks up for all of the operations
// that are running under the user's project.
func (c *Client) Operations(ctx context.Context, zone string) ([]*Op, error) {
	if zone == "" {
		resp, err := c.svc.Projects.Zones.Operations.List(c.projectID, "-").Do()
		if err != nil {
			return nil, err
		}
		return opsFromRaw(resp.Operations), nil
	}
	resp, err := c.svc.Projects.Zones.Operations.List(c.projectID, zone).Do()
	if err != nil {
		return nil, err
	}
	return opsFromRaw(resp.Operations), nil
}

// Operation returns an operation.
func (c *Client) Operation(ctx context.Context, zone, name string) (*Op, error) {
	resp, err := c.svc.Projects.Zones.Operations.Get(c.projectID, zone, name).Do()
	if err != nil {
		return nil, err
	}
	if resp.StatusMessage != "" {
		return nil, errors.New(resp.StatusMessage)
	}
	return opFromRaw(resp), nil
}
