package config

import (
	"fmt"
	"time"
)

// Duration is a [time.Duration] that can be unmarshalled from a TOML string
// (e.g., "30s", "5m"). go-toml v2 does not natively decode strings into
// time.Duration, so this wrapper implements [encoding.TextUnmarshaler].
//
// Access the underlying time.Duration via the embedded field:
//
//	cfg.Server.ReadTimeout.Duration  // time.Duration value
//
// Duration values work directly with time functions that accept
// time.Duration because of the embedding:
//
//	time.After(cfg.Server.ReadTimeout.Duration)
type Duration struct {
	time.Duration
}

// UnmarshalText implements encoding.TextUnmarshaler for TOML string decoding.
func (d *Duration) UnmarshalText(text []byte) error {
	parsed, err := time.ParseDuration(string(text))
	if err != nil {
		return fmt.Errorf("invalid duration %q: %w", string(text), err)
	}
	d.Duration = parsed
	return nil
}

// MarshalText implements encoding.TextMarshaler for TOML string encoding.
func (d Duration) MarshalText() ([]byte, error) {
	return []byte(d.String()), nil
}