// Package validate is the node-engine's own judgement of a declaration, for whoever must know before
// a declaration is sent whether a machine would take it (novox/hq to-be 45 §4, D1; §9, the merge gate).
//
// **One validator.** The controller composed declarations the host then refused whole — a manifest
// the catalogue check passed (novox/hq issue 236), a consumer's identity too long for the machine's
// names (issue 263) — because the only validator was the one the host runs as it applies. A second,
// written in the controller from the host's rules, would drift from them the first time either
// changed. So the host's own parsing is exported here, unchanged: what the controller's self-check and
// the merge gate run is what every machine runs.
//
// It judges a declaration as it arrives over the link: actions are refused, as the host refuses them
// from the link (novox/hq ADR 0005). Nothing here touches a machine.
package validate

import (
	"errors"

	"github.com/novox/mesh-host/internal/declaration"
)

// Declaration is every problem the node-engine would refuse a declaration for, each in its own words;
// nil when it would take it. The body is the declaration as the controller composes it — the bytes a
// signature is made over — not the signed envelope.
func Declaration(raw []byte) []string {
	_, err := declaration.Parse(raw)
	if err == nil {
		return nil
	}
	var refused *declaration.RefusalError
	if errors.As(err, &refused) {
		return refused.Problems
	}
	return []string{err.Error()}
}

// Version is the declaration vocabulary this validator speaks: a declaration of another version is
// refused whole by Declaration, as by the host.
const Version = declaration.Version