package delivery

import (
	"encoding/json"
	"fmt"
)

// The holder's question before it stores a publish (novox/hq ADR 0605 §4, design 51 *Publishing*): did the builder
// number this version with this digest? Every registry seat's holder asks it the same way, so the asking lives here
// once (ADR 0627 §2), beside the builder's layouts; no holder writes it again.
//
// The builder answers it today only as its module's tool builder_versions: no seat in the seat set names the builder's
// role yet. Once one does, BuilderVersionsAddress becomes that seat's verb and nothing else changes for a holder.
const BuilderVersionsAddress = BuilderModule + ".builder_versions"

// AskFunc is the runtime's request and reply over the bus (mesh-sdk stdio.Ask), given by the holder so this package does
// not depend on the runtime.
type AskFunc func(address string, body any) (json.RawMessage, error)

// BuilderVersions asks the builder whether it numbered a version with a digest. It answers the holder's Check:
// recorded, and why not when it is not.
type BuilderVersions struct{ Ask AskFunc }

// Recorded asks the builder about name@version with digest. An answer without `recorded` is an error, never a yes.
func (b BuilderVersions) Recorded(name, version, digest string) (bool, string, error) {
	raw, err := b.Ask(BuilderVersionsAddress, map[string]any{"name": name, "version": version, "digest": digest})
	if err != nil {
		return false, "", err
	}
	var a struct {
		Recorded *bool  `json:"recorded"`
		Why      string `json:"why"`
	}
	if err := json.Unmarshal(raw, &a); err != nil || a.Recorded == nil {
		return false, "", fmt.Errorf("builder_versions answered no recorded: %s", raw)
	}
	return *a.Recorded, a.Why, nil
}