package rpc

import (
	"encoding/base64"

	"github.com/iamxvbaba/td/tg"

	"telesrv/internal/domain"
)

// decodePasskeyID 容忍有/无填充地 base64url 解码 credential id(取第一个可解的非空值)。
func decodePasskeyID(vals ...string) ([]byte, bool) {
	for _, v := range vals {
		if v == "" {
			continue
		}
		if b, err := base64.RawURLEncoding.DecodeString(v); err == nil && len(b) > 0 {
			return b, true
		}
		if b, err := base64.URLEncoding.DecodeString(v); err == nil && len(b) > 0 {
			return b, true
		}
	}
	return nil, false
}

func passkeyPublicKeyCredential(cred tg.InputPasskeyCredentialClass) (*tg.InputPasskeyCredentialPublicKey, bool) {
	pk, ok := cred.(*tg.InputPasskeyCredentialPublicKey)
	return pk, ok
}

// passkeyLoginFromCredential 从 inputPasskeyCredentialPublicKey 提取登录断言字段。
func passkeyLoginFromCredential(cred tg.InputPasskeyCredentialClass) (credID []byte, login *tg.InputPasskeyResponseLogin, ok bool) {
	pk, ok := passkeyPublicKeyCredential(cred)
	if !ok {
		return nil, nil, false
	}
	login, ok = pk.Response.(*tg.InputPasskeyResponseLogin)
	if !ok {
		return nil, nil, false
	}
	credID, ok = decodePasskeyID(pk.RawID, pk.ID)
	if !ok {
		return nil, nil, false
	}
	return credID, login, true
}

// passkeyRegisterFromCredential 从 inputPasskeyCredentialPublicKey 提取注册 attestation 字段。
func passkeyRegisterFromCredential(cred tg.InputPasskeyCredentialClass) (credID []byte, reg *tg.InputPasskeyResponseRegister, ok bool) {
	pk, ok := passkeyPublicKeyCredential(cred)
	if !ok {
		return nil, nil, false
	}
	reg, ok = pk.Response.(*tg.InputPasskeyResponseRegister)
	if !ok {
		return nil, nil, false
	}
	credID, ok = decodePasskeyID(pk.RawID, pk.ID)
	if !ok {
		return nil, nil, false
	}
	return credID, reg, true
}

// tgPasskey 把领域凭据投影为 tg.Passkey(ID 用 base64url)。
func tgPasskey(c domain.PasskeyCredential) tg.Passkey {
	return tg.Passkey{
		ID:            base64.RawURLEncoding.EncodeToString(c.CredentialID),
		Name:          c.Name,
		Date:          int(c.CreatedAt),
		LastUsageDate: int(c.LastUsedAt),
	}
}

func tgPasskeys(creds []domain.PasskeyCredential) []tg.Passkey {
	out := make([]tg.Passkey, 0, len(creds))
	for _, c := range creds {
		out = append(out, tgPasskey(c))
	}
	return out
}