api clients: return data, error, no status

jellyseerr already did this, but it's been standardised a little more.

Mediabrowser uses it's own genericErr function and error types due to
being a separate package, while jellyseerr and ombi now share errors
defined in common/.

common/common.go

@@ -1,8 +1,11 @@
 package common
 
 import (
+	"errors"
 	"fmt"
 	"log"
+
+	lm "github.com/hrfee/jfa-go/logmessages"
 )
 
 // TimeoutHandler recovers from an http timeout or panic.
@@ -12,7 +15,7 @@ type TimeoutHandler func()
 func NewTimeoutHandler(name, addr string, noFail bool) TimeoutHandler {
 	return func() {
 		if r := recover(); r != nil {
-			out := fmt.Sprintf("Failed to authenticate with %s @ \"%s\": Timed out", name, addr)
+			out := fmt.Sprintf(lm.FailedAuth, name, addr, 0, lm.TimedOut)
 			if noFail {
 				log.Print(out)
 			} else {
@@ -21,3 +24,50 @@ func NewTimeoutHandler(name, addr string, noFail bool) TimeoutHandler {
 		}
 	}
 }
+
+// most 404 errors are from UserNotFound, so this generic error doesn't really need any detail.
+type ErrNotFound error
+
+type ErrUnauthorized struct{}
+
+func (err ErrUnauthorized) Error() string {
+	return lm.Unauthorized
+}
+
+type ErrForbidden struct{}
+
+func (err ErrForbidden) Error() string {
+	return lm.Forbidden
+}
+
+var (
+	NotFound ErrNotFound = errors.New(lm.NotFound)
+)
+
+type ErrUnknown struct {
+	code int
+}
+
+func (err ErrUnknown) Error() string {
+	msg := fmt.Sprintf(lm.FailedGenericWithCode, err.code)
+	return msg
+}
+
+// GenericErr returns an error appropriate to the given HTTP status (or actual error, if given).
+func GenericErr(status int, err error) error {
+	if err != nil {
+		return err
+	}
+	switch status {
+	case 200, 204, 201:
+		return nil
+	case 401, 400:
+		return ErrUnauthorized{}
+	case 404:
+		return NotFound
+	case 403:
+		return ErrForbidden{}
+	default:
+		return ErrUnknown{code: status}
+	}
+}