package webrtc

import (
	"encoding/json"
)

// ICETransportPolicy defines the ICE candidate policy surface the
// permitted candidates. Only these candidates are used for connectivity checks.
type ICETransportPolicy int

// ICEGatherPolicy is the ORTC equivalent of ICETransportPolicy
type ICEGatherPolicy = ICETransportPolicy

const (
	// ICETransportPolicyAll indicates any type of candidate is used.
	ICETransportPolicyAll ICETransportPolicy = iota

	// ICETransportPolicyRelay indicates only media relay candidates such
	// as candidates passing through a TURN server are used.
	ICETransportPolicyRelay
)

// This is done this way because of a linter.
const (
	iceTransportPolicyRelayStr = "relay"
	iceTransportPolicyAllStr   = "all"
)

// NewICETransportPolicy takes a string and converts it to ICETransportPolicy
func NewICETransportPolicy(raw string) ICETransportPolicy {
	switch raw {
	case iceTransportPolicyRelayStr:
		return ICETransportPolicyRelay
	case iceTransportPolicyAllStr:
		return ICETransportPolicyAll
	default:
		return ICETransportPolicy(Unknown)
	}
}

func (t ICETransportPolicy) String() string {
	switch t {
	case ICETransportPolicyRelay:
		return iceTransportPolicyRelayStr
	case ICETransportPolicyAll:
		return iceTransportPolicyAllStr
	default:
		return ErrUnknownType.Error()
	}
}

// UnmarshalJSON parses the JSON-encoded data and stores the result
func (t *ICETransportPolicy) UnmarshalJSON(b []byte) error {
	var val string
	if err := json.Unmarshal(b, &val); err != nil {
		return err
	}
	*t = NewICETransportPolicy(val)
	return nil
}

// MarshalJSON returns the JSON encoding
func (t ICETransportPolicy) MarshalJSON() ([]byte, error) {
	return json.Marshal(t.String())
}