// Copyright (c) 2019-2021, Sylabs Inc. All rights reserved.
// This software is licensed under a 3-clause BSD license. Please consult the
// LICENSE.md file distributed with the sources of this project regarding your
// rights to use or distribute this software.

package singularity

import (
	"fmt"
	"io"
	"os"

	"github.com/sylabs/singularity/v4/internal/pkg/remote"
)

// RemoteRemove deletes a remote endpoint from the configuration
func RemoteRemove(configFile, name string) (err error) {
	// opening config file
	file, err := os.OpenFile(configFile, os.O_RDWR|os.O_CREATE, 0o600)
	if err != nil {
		return fmt.Errorf("while opening remote config file: %s", err)
	}
	defer file.Close()

	// read file contents to config struct
	c, err := remote.ReadFrom(file)
	if err != nil {
		return fmt.Errorf("while parsing remote config data: %s", err)
	}

	if err := c.Remove(name); err != nil {
		return err
	}

	// truncating file before writing new contents and syncing to commit file
	if err := file.Truncate(0); err != nil {
		return fmt.Errorf("while truncating remote config file: %s", err)
	}

	if n, err := file.Seek(0, io.SeekStart); err != nil || n != 0 {
		return fmt.Errorf("failed to reset %s cursor: %s", file.Name(), err)
	}

	if _, err := c.WriteTo(file); err != nil {
		return fmt.Errorf("while writing remote config to file: %s", err)
	}

	if err := file.Sync(); err != nil {
		return fmt.Errorf("failed to flush remote config file %s: %s", file.Name(), err)
	}

	return nil
}