package delivery

import (
	"encoding/json"
	"fmt"

	"git.novox.be/novox/mesh-sdk/go/catalogue"
)

// The private network's names as its manifest says them, written here as well as in overlay (Name, Requirement,
// Addressing, TheNetwork), which delivery does not import so its many readers do not reach the network's generator;
// a test keeps them agreeing.
const (
	overlayName        = "mesh-wireguard"
	overlayRequirement = "private-network"
	overlayAddressing  = "mesh-addressing"
	overlayTheNetwork  = "the-private-network"
)

// overlayManifest is overlay.Manifest(): the module the mesh provides for itself.
func overlayManifest() map[string]any {
	return map[string]any{
		"module":   overlayName,
		"version":  "1",
		"computed": overlayName,
		"provides": []string{overlayRequirement, overlayAddressing},
		"claims":   []map[string]any{{"name": overlayTheNetwork, "scope": "node"}},
	}
}

// The modules the mesh provides itself (issue 1126): no repository holds them, so the indexer reads none; their
// manifests come with mesh-sdk, built in code, and always win over any other. Today the private network alone
// (overlay's mesh-wireguard), built by nobody and run inside each node's own composition. One predicate for every part that judges
// or composes a placement: CheckPlacements, the seat's holder, the composer's input (frombus) and the grants part.

// ProvidedModules is every module the mesh provides itself, sorted.
func ProvidedModules() []string { return []string{overlayName} }

// ProvidedByMesh says whether the mesh provides module itself, so a placement may name it with no repository holding it.
func ProvidedByMesh(module string) bool { return module == overlayName }

// ProvidedManifest is a provided module's manifest, as its readers parse it, and its raw JSON; an error for a module the
// mesh does not provide or a manifest its own reader refuses.
func ProvidedManifest(module string) (catalogue.Manifest, []byte, error) {
	if !ProvidedByMesh(module) {
		return catalogue.Manifest{}, nil, fmt.Errorf("delivery: the mesh provides no module %s", module)
	}
	raw, err := json.Marshal(overlayManifest())
	if err != nil {
		return catalogue.Manifest{}, nil, err
	}
	// Decoded as every reader decodes a manifest (novox/hq ADR 0578 §3); its judgement is the indexer's.
	m, err := catalogue.Decode(raw)
	if err != nil {
		return catalogue.Manifest{}, raw, fmt.Errorf("delivery: the manifest mesh-sdk provides for %s does not decode: %w", module, err)
	}
	return m, raw, nil
}