package uci

import (
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"os"

	"forge.cadoles.com/Cadoles/emissary/internal/command/common"
	"forge.cadoles.com/Cadoles/emissary/internal/openwrt/uci"
	"github.com/pkg/errors"
	"github.com/urfave/cli/v2"
)

const (
	FormatJSON = "json"
	FormatUCI  = "uci"
)

func TransformCommand() *cli.Command {
	flags := common.Flags()

	flags = append(flags,
		&cli.StringFlag{
			Name:    "format",
			Aliases: []string{"f"},
			Usage:   "Define the source format ('uci' or 'json')",
			Value:   "uci",
		},
		&cli.StringFlag{
			Name:      "input",
			Usage:     "File to use as input (or '-' for STDIN)",
			Aliases:   []string{"i"},
			TakesFile: true,
			Value:     "-",
		},
	)

	return &cli.Command{
		Name:  "transform",
		Usage: "Transform UCI configuration from/to JSON",
		Flags: flags,
		Action: func(ctx *cli.Context) error {
			input := ctx.String("input")
			format := ctx.String("format")

			var reader io.Reader

			switch input {
			case "-":
				reader = os.Stdin
			default:
				file, err := os.Open(input)
				if err != nil {
					return errors.WithStack(err)
				}

				defer func() {
					if err := file.Close(); err != nil {
						panic(errors.WithStack(err))
					}
				}()

				reader = file
			}

			var conf *uci.UCI

			switch format {
			case FormatJSON:
				decoder := json.NewDecoder(reader)
				conf = uci.NewUCI()

				if err := decoder.Decode(conf); err != nil {
					return errors.WithStack(err)
				}

				fmt.Print(conf.Export())

			case FormatUCI:
				data, err := ioutil.ReadAll(reader)
				if err != nil {
					return errors.WithStack(err)
				}

				conf, err = uci.Parse(data)
				if err != nil {
					return errors.WithStack(err)
				}

				jsonData, err := json.MarshalIndent(conf, "", " ")
				if err != nil {
					return errors.WithStack(err)
				}

				fmt.Print(string(jsonData))

			default:
				return errors.Errorf("unexpected format '%s'", format)
			}

			return nil
		},
	}
}