/*
Copyright (c) 2015 VMware, 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 datastore

import (
	"context"
	"flag"
	"fmt"
	"io"
	"os"
	"text/tabwriter"

	"github.com/vmware/govmomi/govc/cli"
	"github.com/vmware/govmomi/govc/flags"
	"github.com/vmware/govmomi/object"
	"github.com/vmware/govmomi/property"
	"github.com/vmware/govmomi/vim25/mo"
	"github.com/vmware/govmomi/vim25/types"
)

type info struct {
	*flags.ClientFlag
	*flags.OutputFlag
	*flags.DatacenterFlag

	host bool
}

func init() {
	cli.Register("datastore.info", &info{})
}

func (cmd *info) Register(ctx context.Context, f *flag.FlagSet) {
	cmd.ClientFlag, ctx = flags.NewClientFlag(ctx)
	cmd.ClientFlag.Register(ctx, f)

	cmd.OutputFlag, ctx = flags.NewOutputFlag(ctx)
	cmd.OutputFlag.Register(ctx, f)

	cmd.DatacenterFlag, ctx = flags.NewDatacenterFlag(ctx)
	cmd.DatacenterFlag.Register(ctx, f)

	f.BoolVar(&cmd.host, "H", false, "Display info for Datastores shared between hosts")
}

func (cmd *info) Process(ctx context.Context) error {
	if err := cmd.ClientFlag.Process(ctx); err != nil {
		return err
	}
	if err := cmd.OutputFlag.Process(ctx); err != nil {
		return err
	}
	if err := cmd.DatacenterFlag.Process(ctx); err != nil {
		return err
	}
	return nil
}

func (cmd *info) Usage() string {
	return "[PATH]..."
}

func (cmd *info) Description() string {
	return `Display info for Datastores.

Examples:
  govc datastore.info
  govc datastore.info vsanDatastore
  # info on Datastores shared between cluster hosts:
  govc object.collect -s -d " " /dc1/host/k8s-cluster host | xargs govc datastore.info -H
  # info on Datastores shared between VM hosts:
  govc ls /dc1/vm/*k8s* | xargs -n1 -I% govc object.collect -s % summary.runtime.host | xargs govc datastore.info -H`
}

func intersect(common []types.ManagedObjectReference, refs []types.ManagedObjectReference) []types.ManagedObjectReference {
	var shared []types.ManagedObjectReference
	for i := range common {
		for j := range refs {
			if common[i] == refs[j] {
				shared = append(shared, common[i])
				break
			}
		}
	}
	return shared
}

func (cmd *info) Run(ctx context.Context, f *flag.FlagSet) error {
	c, err := cmd.Client()
	if err != nil {
		return err
	}
	pc := property.DefaultCollector(c)

	finder, err := cmd.Finder()
	if err != nil {
		return err
	}

	args := f.Args()
	if len(args) == 0 {
		args = []string{"*"}
	}

	var res infoResult
	var props []string

	if cmd.OutputFlag.All() {
		props = nil // Load everything
	} else {
		props = []string{"info", "summary"} // Load summary
	}

	if cmd.host {
		if f.NArg() == 0 {
			return flag.ErrHelp
		}
		refs, err := cmd.ManagedObjects(ctx, args)
		if err != nil {
			return err
		}

		var hosts []mo.HostSystem
		err = pc.Retrieve(ctx, refs, []string{"name", "datastore"}, &hosts)
		if err != nil {
			return err
		}

		refs = hosts[0].Datastore
		for _, host := range hosts[1:] {
			refs = intersect(refs, host.Datastore)
			if len(refs) == 0 {
				return fmt.Errorf("host %s (%s) has no shared datastores", host.Name, host.Reference())
			}
		}
		for i := range refs {
			ds, err := finder.ObjectReference(ctx, refs[i])
			if err != nil {
				return err
			}
			res.objects = append(res.objects, ds.(*object.Datastore))
		}
	} else {
		for _, arg := range args {
			objects, err := finder.DatastoreList(ctx, arg)
			if err != nil {
				return err
			}
			res.objects = append(res.objects, objects...)
		}
	}

	if len(res.objects) != 0 {
		refs := make([]types.ManagedObjectReference, 0, len(res.objects))
		for _, o := range res.objects {
			refs = append(refs, o.Reference())
		}

		err = pc.Retrieve(ctx, refs, props, &res.Datastores)
		if err != nil {
			return err
		}
	}

	return cmd.WriteResult(&res)
}

type infoResult struct {
	Datastores []mo.Datastore
	objects    []*object.Datastore
}

func (r *infoResult) Write(w io.Writer) error {
	// Maintain order via r.objects as Property collector does not always return results in order.
	objects := make(map[types.ManagedObjectReference]mo.Datastore, len(r.Datastores))
	for _, o := range r.Datastores {
		objects[o.Reference()] = o
	}

	tw := tabwriter.NewWriter(os.Stdout, 2, 0, 2, ' ', 0)

	for _, o := range r.objects {
		ds := objects[o.Reference()]
		s := ds.Summary
		fmt.Fprintf(tw, "Name:\t%s\n", s.Name)
		fmt.Fprintf(tw, "  Path:\t%s\n", o.InventoryPath)
		fmt.Fprintf(tw, "  Type:\t%s\n", s.Type)
		fmt.Fprintf(tw, "  URL:\t%s\n", s.Url)
		fmt.Fprintf(tw, "  Capacity:\t%.1f GB\n", float64(s.Capacity)/(1<<30))
		fmt.Fprintf(tw, "  Free:\t%.1f GB\n", float64(s.FreeSpace)/(1<<30))

		switch info := ds.Info.(type) {
		case *types.NasDatastoreInfo:
			fmt.Fprintf(tw, "  Remote:\t%s:%s\n", info.Nas.RemoteHost, info.Nas.RemotePath)
		}
	}

	return tw.Flush()
}