package appconfig

import (
	"context"
	"crypto/ecdh"
	"github.com/carlosframework/platform/internal/hostwrite"
	"github.com/carlosframework/platform/internal/registry"
	"github.com/carlosframework/platform/internal/release"
)

// CheckRenderedIdentity recomputes the exact current ordinary render. It is
// read-only and uses the same merge, binding and encoding as the config writers.
func CheckRenderedIdentity(ctx context.Context, s release.Store, priv *ecdh.PrivateKey, rt registry.Route, id hostwrite.Identity) error {
	if id.Config == "" || id.Release != "" {
		return hostwrite.ErrUnavailable
	}
	m, versions, err := LoadMergedHostVersions(ctx, s, release.RouteAccount(rt), rt.App, rt.Environment, rt.Host)
	if err != nil {
		return err
	}
	var rendered []byte
	if m != nil {
		rendered, err = RenderEnv(m, priv, routeBinding(rt))
		if err != nil {
			return err
		}
		if rt.Unit != "" {
			rendered = applyAgentVars(rendered)
		} else if rt.Addr != "" {
			rendered = append([]byte(execAddrConfigHeader), rendered...)
		}
	}
	defaultPresent := m != nil
	if rt.Unit != "" {
		defaultPresent = versions.Default != ""
	}
	expected := renderedIdentity(rendered, defaultPresent, rt.Environment != "", versions.Overlay != "")
	if id != expected {
		return hostwrite.ErrUnavailable
	}
	return nil
}