efritz/ij

package util

import (
    "encoding/json"
    "fmt"
    "time"
)

type Duration struct {
    time.Duration
}

var ZeroDuration = Duration{time.Duration(0)}

func (d Duration) String() string {
    if d.Duration == 0 {
        return ""
    }

    return d.Duration.String()
}

func (d Duration) MarshalJSON() ([]byte, error) {
    return json.Marshal(d.String())
}

func (d *Duration) UnmarshalJSON(data []byte) error {
    val := ""
    err := json.Unmarshal(data, &val)

    if err == nil {
        parsed, err := time.ParseDuration(val)
        if err != nil {
            return err
        }

        *d = Duration{parsed}
        return nil
    }

    return fmt.Errorf(
        "%s is not a valid duration",
        string(data),
    )
}

func UnmarshalStringList(raw json.RawMessage) ([]string, error) {
    if len(raw) == 0 {
        return nil, nil
    }

    single := ""
    if err := json.Unmarshal(raw, &single); err == nil {
        return []string{single}, nil
    }

    multiple := []string{}
    if err := json.Unmarshal(raw, &multiple); err != nil {
        return nil, err
    }

    return multiple, nil
}