package main

// keycloak's provisioner — the adapter that makes keycloak a provider of the mesh `oidc-client`
// interface (novox/hq ADR 0039/0040/0048). The reconcile loop is harness.go's; this writes only how
// Keycloak creates, checks and removes a consumer's client. What a client is, is oidc.go's.
//
// **The realm is read out of the issuer**, the one value an assignment sets (settings reach both the
// served facts and this module's config.json): a realm set in one place and an issuer in another
// would let the consumer be told one realm while its client is made in another.
//
// **While the admin is refused, Keycloak is not asked** (admin.go): every attempt would be one more
// failed login against the admin. The harness still counts each pass as a failure of the consumer,
// classed credentials-rejected, so the standing it announces says what is wrong.

import (
	"context"
	"errors"
	"fmt"
	"os"
	"time"
)

// Issuer is the issuer this assignment serves, from the settings-merged config the mesh delivers.
func Issuer(getenv func(string) string) (string, error) {
	if said := cfgString(meshConfig(getenv("MESH_KEYCLOAK_CONFIG_FILE")), "issuer"); said != "" {
		return said, nil
	}
	if said := getenv("MESH_KEYCLOAK_ISSUER"); said != "" {
		return said, nil
	}
	return "", errors.New("no issuer — the module's config.json carries none and MESH_KEYCLOAK_ISSUER is unset")
}

// provisioner is the adapter.
type provisioner struct {
	clients  OidcClients
	guard    *Guard
	announce func(event string, body map[string]any)
	log      func(format string, args ...any)
}

func (a provisioner) refused() error {
	if a.guard != nil && a.guard.Refused() {
		return ErrAdminRejected
	}
	return nil
}

func (a provisioner) Create(ctx context.Context, p Provision) error {
	if err := a.refused(); err != nil {
		return err
	}
	done, err := a.clients.Ensure(ctx, p)
	if err != nil {
		return err
	}
	if done == "created" {
		a.log("[provisioner:oidc-client] created client %s in realm %s", p.As, a.clients.Realm)
		a.announce("client.created", map[string]any{"realm": a.clients.Realm, "clientId": p.As, "consumer": p.Consumer})
	}
	return nil
}

// Retire disables the consumer's client and marks it, never deletes it (novox/hq ADR 0230).
func (a provisioner) Retire(ctx context.Context, as string, _ map[string]any, why string, at time.Time) error {
	if err := a.refused(); err != nil {
		return err
	}
	done, err := a.clients.Retire(ctx, as, why, at)
	if err != nil {
		return err
	}
	switch done {
	case "not ours":
		a.log("[provisioner:oidc-client] %s: a client of that id exists that the mesh did not make — left alone", as)
	case "retired":
		a.log("[provisioner:oidc-client] retired client %s in realm %s: disabled, kept, marked to delete", as, a.clients.Realm)
		a.announce("client.retired", map[string]any{"realm": a.clients.Realm, "clientId": as})
	}
	return nil
}

// Inventory is every client in the realm the mesh made, active and retired.
func (a provisioner) Inventory(ctx context.Context) (Inventory, error) {
	if err := a.refused(); err != nil {
		return Inventory{}, err
	}
	return a.clients.Inventory(ctx)
}

// Delete removes a retired client, a person's act through `cleanup delete`. Nothing is freed that
// Keycloak counts in bytes.
func (a provisioner) Delete(ctx context.Context, r Retired) (int64, error) {
	if err := a.refused(); err != nil {
		return 0, err
	}
	if err := a.clients.Delete(ctx, r.Consumer); err != nil {
		return 0, err
	}
	a.log("[provisioner:oidc-client] deleted retired client %s from realm %s", r.Consumer, a.clients.Realm)
	return -1, nil
}

// Holds is asked every minute by the harness: whether Keycloak still holds this consumer's client
// exactly as the mesh gave it, so one deleted or edited behind the mesh's back is made again
// (novox/hq issue 120).
func (a provisioner) Holds(ctx context.Context, p Provision) (bool, error) {
	if err := a.refused(); err != nil {
		return false, err
	}
	return a.clients.Holds(ctx, p)
}

// Class says a refused admin is a credentials problem, whatever the words around it.
func (provisioner) Class(err error) string {
	if errors.Is(err, ErrRejected) {
		return ClassCredentials
	}
	return ""
}

func logStderr(format string, args ...any) { fmt.Fprintf(os.Stderr, format+"\n", args...) }