// Copyright (c) 2015-2022 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"github.com/minio/cli"
	"github.com/minio/madmin-go/v3"
	"github.com/minio/mc/pkg/probe"
)

const (
	errCodeChangeAlreadyApplied = "XMinioAdminPolicyChangeAlreadyApplied"
)

var adminAttachPolicyFlags = []cli.Flag{
	cli.StringFlag{
		Name:  "user, u",
		Usage: "attach policy to user",
	},
	cli.StringFlag{
		Name:  "group, g",
		Usage: "attach policy to group",
	},
}

var adminPolicyAttachCmd = cli.Command{
	Name:         "attach",
	Usage:        "attach an IAM policy to a user or group",
	Action:       mainAdminPolicyAttach,
	OnUsageError: onUsageError,
	Before:       setGlobalsFromContext,
	Flags:        append(adminAttachPolicyFlags, globalFlags...),
	CustomHelpTemplate: `NAME:
  {{.HelpName}} - {{.Usage}}

USAGE:
  {{.HelpName}} [FLAGS] TARGET POLICY [POLICY...] [--user USER | --group GROUP]

  Exactly one of --user or --group is required.

POLICY:
  Name of the policy on the MinIO server.

FLAGS:
  {{range .VisibleFlags}}{{.}}
  {{end}}
EXAMPLES:
  1. Attach the "readonly" policy to user "james".
     {{.Prompt}} {{.HelpName}} myminio readonly --user james
  2. Attach the "audit-policy" and "acct-policy" policies to group "legal".
     {{.Prompt}} {{.HelpName}} myminio audit-policy acct-policy --group legal
`,
}

// mainAdminPolicyAttach is the handler for "mc admin policy attach" command.
func mainAdminPolicyAttach(ctx *cli.Context) error {
	return userAttachOrDetachPolicy(ctx, true)
}

func userAttachOrDetachPolicy(ctx *cli.Context, attach bool) error {
	if len(ctx.Args()) < 2 {
		showCommandHelpAndExit(ctx, 1) // last argument is exit code
	}
	user := ctx.String("user")
	group := ctx.String("group")

	// Get the alias parameter from cli
	args := ctx.Args()
	aliasedURL := args.Get(0)

	policies := args[1:]
	req := madmin.PolicyAssociationReq{
		User:     user,
		Group:    group,
		Policies: policies,
	}

	// Create a new MinIO Admin Client
	client, err := newAdminClient(aliasedURL)
	fatalIf(err, "Unable to initialize admin connection.")

	var e error
	var res madmin.PolicyAssociationResp
	if attach {
		res, e = client.AttachPolicy(globalContext, req)
	} else {
		res, e = client.DetachPolicy(globalContext, req)
	}

	if e != nil && madmin.ToErrorResponse(e).Code != errCodeChangeAlreadyApplied {
		fatalIf(probe.NewError(e), "Unable to make user/group policy association")
	}

	var emptyResp madmin.PolicyAssociationResp
	if res.UpdatedAt == emptyResp.UpdatedAt {
		// Older minio does not send a result, so we populate res manually to
		// simulate a result. TODO(aditya): remove this after newer minio is
		// released in a few months (Older API Deprecated in Jun 2023)
		if attach {
			res.PoliciesAttached = policies
		} else {
			res.PoliciesDetached = policies
		}
	}

	m := policyAssociationMessage{
		attach:           attach,
		Status:           "success",
		PoliciesAttached: res.PoliciesAttached,
		PoliciesDetached: res.PoliciesDetached,
		User:             user,
		Group:            group,
	}
	printMsg(m)
	return nil
}
