errors.go

package chttp

import (
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
)

var (
	ErrStatusCode = fmt.Errorf("wrong status code")
	ErrUnknown    = fmt.Errorf("unknown error")
)

type Error struct {
	Response *http.Response
	Body     []byte
	Base     error
}

func newError(response *http.Response, body []byte, err error) *Error {
	return &Error{
		Response: response,
		Body:     body,
		Base:     err,
	}
}

func (e *Error) IsStatusCode() bool {
	if e == nil {
		return false
	}
	if e.Base != nil {
		return false
	}
	if e.Response != nil {
		return e.Response.StatusCode >= http.StatusMultipleChoices
	}
	return false
}

func (e *Error) Error() string {
	if e == nil {
		return ""
	}
	return e.Unwrap().Error()
}

func (e *Error) Unwrap() error {
	if e.Base != nil {
		return e.Base
	}
	if e.Response != nil {
		return fmt.Errorf("%w, status_code=%d", ErrStatusCode, e.Response.StatusCode)
	}
	return ErrUnknown
}

func (e *Error) UnmarshalTo(value interface{}) (bool, error) {
	if e.IsStatusCode() {
		err := json.Unmarshal(e.Body, &value)
		if err != nil {
			return false, err
		}
		return true, nil
	}
	return false, nil
}

func ErrorUnmarshalTo[Result any](err error) (result Result, _ error) {
	base := new(Error)
	if errors.As(err, &base) {
		if ok, err := base.UnmarshalTo(&result); err != nil {
			return result, err
		} else if ok {
			return result, nil
		}
	}
	return result, err
}