package errors

import (
	"errors"
	"fmt"

	"go.uber.org/zap"
	"google.golang.org/genproto/googleapis/rpc/errdetails"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

type ErrorType int

const (
	BusinessError ErrorType = iota
	InternalErrorType
)

type AppError struct {
	Code    string
	Message string
	Type    ErrorType
	Err     error
}

func (e *AppError) Error() string {
	if e.Err != nil {
		return fmt.Sprintf("%s: %s (%v)", e.Code, e.Message, e.Err)
	}
	return fmt.Sprintf("%s: %s", e.Code, e.Message)
}

func (e *AppError) Unwrap() error {
	return e.Err
}

func NewBusinessError(code, message string) *AppError {
	return &AppError{
		Code:    code,
		Message: message,
		Type:    BusinessError,
	}
}

func NewInternalError(code, message string, err error) *AppError {
	return &AppError{
		Code:    code,
		Message: message,
		Type:    InternalErrorType,
		Err:     err,
	}
}

func IsBusinessError(err error, code string) bool {
	var appErr *AppError
	if !errors.As(err, &appErr) {
		return false
	}
	return appErr.Type == BusinessError && appErr.Code == code
}

func ToGRPCError(err error, zapLogger *zap.Logger, method string) error {
	if err == nil {
		return nil
	}

	var appErr *AppError
	ok := errors.As(err, &appErr)
	if !ok {
		if zapLogger != nil {
			zapLogger.Error("gRPC handler error: unknown error type",
				zap.String("method", method),
				zap.Error(err),
			)
		}
		return status.Error(codes.Internal, "internal server error")
	}

	if appErr.Type == InternalErrorType {
		if zapLogger != nil {
			zapLogger.Error("gRPC handler error: internal error",
				zap.String("method", method),
				zap.String("code", appErr.Code),
				zap.String("message", appErr.Message),
				zap.Error(appErr.Err),
			)
		}
		return status.Error(codes.Internal, "internal server error")
	}

	var grpcCode codes.Code
	switch appErr.Code {
	case AuthInvalidCredentials, AuthMissing, AuthInvalidToken, RefreshInvalid:
		grpcCode = codes.Unauthenticated
	case PermissionDenied:
		grpcCode = codes.PermissionDenied
	case InviteLimitReached:
		grpcCode = codes.ResourceExhausted
	case InsufficientBalance:
		grpcCode = codes.FailedPrecondition
	case InviteInvalidOrExpired:
		grpcCode = codes.NotFound
	case EmailAlreadyExists:
		grpcCode = codes.AlreadyExists
	case UserNotFound, RequestNotFound:
		grpcCode = codes.NotFound
	default:
		grpcCode = codes.Unknown
	}

	st, err := status.New(grpcCode, appErr.Message).WithDetails(&errdetails.ErrorInfo{
		Reason: appErr.Code,
	})
	if err != nil {
		return status.Error(grpcCode, appErr.Message)
	}
	return st.Err()
}