package errors

import (
	"errors"
	"fmt"
	httpstatus "git.diulo.com/mogfee/kit/transport/http/status"
	"google.golang.org/genproto/googleapis/rpc/errdetails"
	"google.golang.org/grpc/status"
)

const (
	// UnknownCode is unknown code for error info.
	UnknownCode = 500
	// UnknownReason is unknown reason for error info.
	UnknownReason = ""
)

type Error struct {
	Status
	cause error
}

func (e *Error) Error() string {
	return fmt.Sprintf("error: code = %d reason = %s message = %s metadata = %v cause = %v", e.Code, e.Reason, e.Message, e.Metadata, e.cause)
}
func (e *Error) Unwarp() error {
	return e.cause
}
func (e *Error) Is(err error) bool {
	if se := new(Error); errors.As(err, &se) {
		return se.Code == e.Code && se.Reason == e.Reason
	}
	return false
}
func (e *Error) WithCause(cause error) *Error {
	err := Clone(e)
	err.cause = cause
	return err
}
func (e *Error) WithMetadata(md map[string]string) *Error {
	err := Clone(e)
	err.Metadata = md
	return err
}

func (e *Error) GRPCStatus() *status.Status {
	s, _ := status.New(httpstatus.ToGRPCCode(int(e.Code)), e.Message).
		WithDetails(&errdetails.ErrorInfo{
			Reason:   e.Reason,
			Metadata: e.Metadata,
		})
	return s
}
func New(code int, reason, message string) *Error {
	return &Error{
		Status: Status{
			Code:    int32(code),
			Reason:  reason,
			Message: message,
		},
	}
}
func Newf(code int, reason string, format string, a ...any) *Error {
	return New(code, reason, fmt.Sprintf(format, a...))
}
func Errorf(code int, reason string, format string, a ...any) *Error {
	return New(code, reason, fmt.Sprintf(format, a...))
}
func Code(err error) int {
	if err == nil {
		return 200
	}
	return int(FromError(err).Code)
}
func Reason(err error) string {
	if err == nil {
		return UnknownReason
	}
	return FromError(err).Reason
}

func Clone(err *Error) *Error {
	if err == nil {
		return nil
	}
	metadata := make(map[string]string, len(err.Metadata))
	for k, v := range err.Metadata {
		metadata[k] = v
	}
	return &Error{
		cause: err.cause,
		Status: Status{
			Code:     err.Code,
			Reason:   err.Reason,
			Message:  err.Message,
			Metadata: metadata,
		},
	}
}

func FromError(err error) *Error {
	if err == nil {
		return nil
	}
	if se := new(Error); errors.As(err, &se) {
		return se
	}
	gs, ok := status.FromError(err)
	if !ok {
		return New(UnknownCode, UnknownReason, err.Error())
	}
	ret := New(httpstatus.FromGRPCCode(gs.Code()), UnknownReason, gs.Message())
	for _, detail := range gs.Details() {
		switch d := detail.(type) {
		case *errdetails.ErrorInfo:
			ret.Reason = d.Reason
			return ret.WithMetadata(d.Metadata)
		}
	}
	return ret
}