// Driver registry — the catalog of selectable device drivers.
//
// This is what makes the system admin-configurable: each category (access /
// reader / camera / printer) has multiple drivers, and the first-run setup UI
// reads this catalog to let the admin pick one per lane and fill in its config.
// Adding support for a new device = registering one more driver here; no
// business-logic changes. See wiki/concepts/device-registry.md.

import type {
  AccessControlDevice,
  CameraDevice,
  Device,
  DeviceCategory,
  PrinterDevice,
  ReaderDevice,
} from "./interfaces.js";

/** A single configurable connection field shown in the setup wizard. */
export interface ConfigField {
  readonly key: string;
  readonly label: string;
  readonly type: "string" | "number" | "boolean" | "host" | "port" | "secret" | "select";
  readonly required: boolean;
  readonly default?: string | number | boolean;
  /** For type "select". */
  readonly options?: readonly { value: string; label: string }[];
  readonly help?: string;
}

/** Opaque per-instance config the admin fills in (host, port, credentials…). */
export type DeviceConfig = Record<string, string | number | boolean>;

/**
 * A driver: metadata describing a supported device model/family, the config
 * fields the admin must supply, and a factory that builds a live adapter.
 */
export interface DeviceDriver<T extends Device = Device> {
  readonly id: string; // stable, e.g. "dingtian", "hikvision"
  readonly category: DeviceCategory;
  readonly label: string; // human name for the picker, e.g. "Dingtian relay controller"
  readonly description: string;
  /** Transports/notes surfaced in the UI, e.g. ["tcp-ip"], ["wiegand"]. */
  readonly transports: readonly string[];
  readonly configFields: readonly ConfigField[];
  /** Build a live adapter instance from validated config. */
  create(config: DeviceConfig): T;
}

export type AccessDriver = DeviceDriver<AccessControlDevice>;
export type ReaderDriver = DeviceDriver<ReaderDevice>;
export type CameraDriver = DeviceDriver<CameraDevice>;
export type PrinterDriver = DeviceDriver<PrinterDevice>;

/** A device found on the LAN by a driver's discovery scan. */
export interface DiscoveredDevice {
  /** Identifier to pre-fill (e.g. a serial number). */
  readonly id: string;
  readonly label: string;
  /** Config values to auto-fill into the setup form (host, serial, …). */
  readonly config: DeviceConfig;
  /** Extra info to show the admin (firmware, MAC, netmask, …). */
  readonly info?: Record<string, string>;
}

/**
 * Optional capability: a driver that can find devices on the LAN (e.g. UDP
 * broadcast discovery). No bundled driver implements this yet — the Dingtian
 * board uses a fixed IP; cameras (ONVIF) or other UDP-discoverable devices may
 * add it later. See wiki/concepts/device-discovery.md.
 */
export interface DiscoverableDriver {
  discover(): Promise<DiscoveredDevice[]>;
}

/** Type guard: does this driver support discovery? */
export function isDiscoverable(
  driver: DeviceDriver,
): driver is DeviceDriver & DiscoverableDriver {
  return typeof (driver as Partial<DiscoverableDriver>).discover === "function";
}

class DeviceRegistry {
  readonly #drivers = new Map<string, DeviceDriver>();

  register(driver: DeviceDriver): void {
    if (this.#drivers.has(driver.id)) {
      throw new Error(`duplicate driver id: ${driver.id}`);
    }
    this.#drivers.set(driver.id, driver);
  }

  /** All drivers, optionally filtered by category (used by the setup catalog). */
  list(category?: DeviceCategory): DeviceDriver[] {
    const all = [...this.#drivers.values()];
    return category ? all.filter((d) => d.category === category) : all;
  }

  get(id: string): DeviceDriver | undefined {
    return this.#drivers.get(id);
  }

  /** Validate config against a driver's declared fields and build the adapter. */
  create(id: string, config: DeviceConfig): Device {
    const driver = this.#drivers.get(id);
    if (!driver) throw new Error(`unknown driver: ${id}`);
    for (const field of driver.configFields) {
      if (field.required && config[field.key] === undefined) {
        throw new Error(`driver ${id}: missing required config "${field.key}"`);
      }
    }
    return driver.create(config);
  }

  /** Catalog payload for the setup UI — drivers grouped by category, no secrets. */
  catalog() {
    const byCategory: Record<DeviceCategory, CatalogEntry[]> = {
      access: [],
      reader: [],
      camera: [],
      printer: [],
    };
    for (const d of this.#drivers.values()) {
      byCategory[d.category].push({
        id: d.id,
        label: d.label,
        description: d.description,
        transports: d.transports,
        configFields: d.configFields,
      });
    }
    return byCategory;
  }
}

export interface CatalogEntry {
  readonly id: string;
  readonly label: string;
  readonly description: string;
  readonly transports: readonly string[];
  readonly configFields: readonly ConfigField[];
}

/** Singleton registry. Drivers self-register on import (see ./drivers). */
export const registry = new DeviceRegistry();