package configkit

import (
	"encoding/json"
	"fmt"
	"io"
	"reflect"
	"strconv"

	"gitea.maximumdirect.net/eric/ConfigKit/internal/engine"
)

// Secret is an opaque reference to an environment variable. Its name is public
// configuration; its resolved value is available only through Value.
type Secret struct {
	name, value         string
	specified, resolved bool
}

// SecretEnv constructs an unresolved environment-backed secret reference.
// Invalid names are reported if the reference survives a configuration load.
func SecretEnv(name string) Secret { return Secret{name: name, specified: true} }

// EnvName returns the public environment-variable name.
func (s Secret) EnvName() string { return s.name }

// Value returns the resolved credential, or an empty string when unresolved.
func (s Secret) Value() string {
	if !s.resolved {
		return ""
	}
	return s.value
}

// IsResolved reports whether this reference resolved to a nonempty value during its configuration load.
func (s Secret) IsResolved() bool { return s.resolved }

// Format renders only the public reference name for every formatting verb.
func (s Secret) Format(state fmt.State, _ rune) {
	_, _ = io.WriteString(state, "configkit.SecretEnv("+strconv.Quote(s.name)+")")
}

// MarshalJSON emits only the public environment-variable name.
func (s Secret) MarshalJSON() ([]byte, error) { return json.Marshal(s.name) }

func secretBinding() engine.SecretBinding {
	return engine.SecretBinding{Type: reflect.TypeFor[Secret](), Read: func(value reflect.Value) engine.SecretState {
		secret := value.Interface().(Secret)
		return engine.SecretState{Name: secret.name, Value: secret.value, Specified: secret.specified, Resolved: secret.resolved}
	}, Make: func(state engine.SecretState) reflect.Value {
		return reflect.ValueOf(Secret{name: state.Name, value: state.Value, specified: state.Specified, resolved: state.Resolved})
	}}
}