// tera-recovery-request-tool creates and inspects the exact 2 KiB BCB record
// used by the target recovery protocol. It never writes a target block device.
package main

import (
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"os"

	"tera-clone/services/tera-api/internal/update/recoveryrequest"
)

func main() {
	if len(os.Args) < 2 {
		usage()
	}
	var err error
	switch os.Args[1] {
	case "create":
		err = create(os.Args[2:])
	case "clear":
		err = clear(os.Args[2:])
	case "inspect":
		err = inspect(os.Args[2:])
	default:
		usage()
	}
	if err != nil {
		fmt.Fprintln(os.Stderr, "tera-recovery-request-tool:", err)
		os.Exit(1)
	}
}

func usage() {
	fmt.Fprintln(os.Stderr, "usage: tera-recovery-request-tool {create|clear|inspect} [flags]")
	os.Exit(2)
}

func clear(arguments []string) error {
	flags := flag.NewFlagSet("clear", flag.ContinueOnError)
	output := flags.String("output", "", "new 2048-byte cleared BCB record path")
	if err := flags.Parse(arguments); err != nil {
		return err
	}
	if *output == "" {
		return errors.New("output is required")
	}
	file, err := os.OpenFile(*output, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o600)
	if err != nil {
		return err
	}
	encoded := recoveryrequest.Clear()
	written, writeErr := file.Write(encoded)
	syncErr := file.Sync()
	closeErr := file.Close()
	if writeErr != nil || written != recoveryrequest.Size {
		_ = os.Remove(*output)
		return fmt.Errorf("write cleared BCB record: wrote %d of %d bytes: %w", written, recoveryrequest.Size, writeErr)
	}
	if syncErr != nil {
		_ = os.Remove(*output)
		return syncErr
	}
	if closeErr != nil {
		_ = os.Remove(*output)
		return closeErr
	}
	fmt.Printf("created cleared BCB record: %s (misc offset %d)\n", *output, recoveryrequest.Offset)
	return nil
}

func create(arguments []string) error {
	flags := flag.NewFlagSet("create", flag.ContinueOnError)
	operationID := flags.String("operation-id", "", "validated update operation id")
	output := flags.String("output", "", "new 2048-byte BCB record path")
	if err := flags.Parse(arguments); err != nil {
		return err
	}
	if *output == "" {
		return errors.New("output is required")
	}
	encoded, err := recoveryrequest.Encode(*operationID)
	if err != nil {
		return err
	}
	file, err := os.OpenFile(*output, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o600)
	if err != nil {
		return err
	}
	written, writeErr := file.Write(encoded)
	syncErr := file.Sync()
	closeErr := file.Close()
	if writeErr != nil || written != recoveryrequest.Size {
		_ = os.Remove(*output)
		return fmt.Errorf("write BCB record: wrote %d of %d bytes: %w", written, recoveryrequest.Size, writeErr)
	}
	if syncErr != nil {
		_ = os.Remove(*output)
		return syncErr
	}
	if closeErr != nil {
		_ = os.Remove(*output)
		return closeErr
	}
	fmt.Printf("created recovery BCB record: %s (misc offset %d)\n", *output, recoveryrequest.Offset)
	return nil
}

func inspect(arguments []string) error {
	flags := flag.NewFlagSet("inspect", flag.ContinueOnError)
	input := flags.String("input", "", "2048-byte BCB record path")
	if err := flags.Parse(arguments); err != nil {
		return err
	}
	data, err := os.ReadFile(*input)
	if err != nil {
		return err
	}
	message, err := recoveryrequest.Decode(data)
	if err != nil {
		return err
	}
	return json.NewEncoder(os.Stdout).Encode(map[string]any{
		"valid": true, "command": recoveryrequest.Command,
		"operation_id": message.OperationID, "misc_offset": recoveryrequest.Offset,
		"record_bytes": recoveryrequest.Size,
	})
}