// Copyright (c) 2020, Andreas Schneider
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//     * Neither the name of the <organization> nor the
//       names of its contributors may be used to endorse or promote products
//       derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package main

import (
	"fmt"
	"os"

	"golang.org/x/crypto/bcrypt"
)

type CmdUser struct {
	CmdList   CmdUserList   `cmd:"" name:"list" help:"List all users."`
	CmdAdd    CmdUserAdd    `cmd:"" name:"add" help:"Add a user."`
	CmdUpdate CmdUserUpdate `cmd:"" name:"update" help:"Update a user."`
	CmdDelete CmdUserDelete `cmd:"" name:"delete" help:"Delete a user."`
}

type CmdUserList struct{}

func (cmd CmdUserList) Run(app *app) error {
	users, err := app.userStore.GetUsers()
	if err != nil {
		return err
	}

	for _, user := range users {
		fmt.Printf("* %s (%s)\n", user.Username, user.Role)
	}

	return nil
}

type CmdUserAdd struct {
	Username string `arg:"" name:"username" help:"The username to be added."`
	PasswordParam
	Role GlobalRole `name:"role" default:"user" help:"Role of the user. 'admin' or ' user'"`
}

func (cmd CmdUserAdd) Run(app *app) error {
	switch cmd.Role {
	case GlobalRoleUser:
	case GlobalRoleAdmin:
	default:
		return fmt.Errorf("invalid user role")
	}

	password, err := cmd.acquirePassword()
	if err != nil {
		return fmt.Errorf("cannot acquire password for user: %w", err)
	}

	user := User{
		Username: cmd.Username,
		Password: password,
		Role:     cmd.Role,
	}
	return app.userStore.AddUser(user)
}

type CmdUserUpdate struct {
	Username string     `arg:"" name:"username" help:"The username of the user to be updated."`
	Password string     `name:"password" help:"Update the password, if set."`
	Role     GlobalRole `name:"role" default:"user" help:"Update the role, if set. 'admin' or ' user'"`
}

func (cmd CmdUserUpdate) Run(app *app) error {
	user, err := app.userStore.GetUser(cmd.Username)
	if err != nil {
		return err
	}

	changed := false

	if cmd.Role != "" && cmd.Role != user.Role {
		switch cmd.Role {
		case GlobalRoleUser:
		case GlobalRoleAdmin:
		default:
			return fmt.Errorf("invalid user role")
		}

		user.Role = cmd.Role
		changed = true
	}

	if cmd.Password != "" {
		hash, err := bcrypt.GenerateFromPassword([]byte(cmd.Password), 0)
		if err != nil {
			return fmt.Errorf("cannot hash password: %w", err)
		}
		user.Password = string(hash)
		changed = true
	}

	if !changed {
		// Nothing changed. Nothing to write. Not different from a successful write to the user.
		return nil
	}

	return app.userStore.UpdateUser(user)
}

type CmdUserDelete struct {
	Username string `arg:"" name:"username" help:"The username of the user to be deleted."`
}

func (cmd CmdUserDelete) Run(app *app) error {
	if err := app.userStore.RemoveUser(cmd.Username); err != nil {
		return fmt.Errorf("cannot remove user: %w", err)
	}

	sharesByUser, err := app.shareStore.FindSharesByUser(cmd.Username)
	if err != nil {
		return fmt.Errorf("cannot get shares of user: %w", err)
	}
	allSuccessful := true
	for _, userShare := range sharesByUser {
		if err := app.shareStore.RemoveShare(userShare.UUID); err != nil {
			fmt.Fprintf(os.Stderr, "User %q cannot be removed from Share %q: %v\n", cmd.Username, userShare.UUID.String(), err)
			allSuccessful = false
		}
	}
	if !allSuccessful {
		return fmt.Errorf("could not remove user from all shares")
	}
	return nil
}