package holder

import (
	"encoding/json"
	"fmt"

	"git.novox.be/novox/mesh-delivery/contracts/go/seats/meshbuilds"
)

// Reserved is the holder's check of a publish against the builder's reservation (novox/hq design 47 §381, §478, §504): it asks the
// seat mesh-builds' verb reserved with the publish's name and version, a package's name in its ecosystem, and accepts the publish
// only when that version is the one reserved and an artifact of it has the publish's digest. It reads no catalog and a publish gains
// no field. It is the Builder the holder's Check asks.
type Reserved struct {
	// Ask is the runtime's request and reply over the bus (mesh-sdk stdio.Ask).
	Ask func(address string, body any) (json.RawMessage, error)
}

// Address is the seat verb asked, as the manifest's `invokes` names it.
const Address = "seat:" + meshbuilds.Seat + "." + meshbuilds.VerbReserved

// Recorded answers whether name@version with digest is reserved, and why not when it is not. An answer that cannot be read is an
// error, never a yes; a refusal by the builder (a name no entry carries, a version it did not reserve) is a no that names it.
func (r Reserved) Recorded(name, version, digest string) (bool, string, error) {
	raw, err := r.Ask(Address, meshbuilds.ReservedInput{Name: name, Version: version})
	if err != nil {
		return false, "", fmt.Errorf("%s did not answer for %s@%s: %w", Address, name, version, err)
	}
	var a meshbuilds.ReservedAnswer
	if err := json.Unmarshal(raw, &a); err != nil || a.Version == "" {
		return false, "", fmt.Errorf("%s answered no reservation for %s@%s: %s", Address, name, version, raw)
	}
	if a.Version != version {
		return false, fmt.Sprintf("%s reserved %s for %s, not %s", a.Module, a.Version, name, version), nil
	}
	for _, art := range a.Artifacts {
		if art.Digest == digest {
			return true, "", nil
		}
	}
	return false, fmt.Sprintf("%s reserved %s@%s for another digest than %s", a.Module, name, version, digest), nil
}