/**
 * Device Store — visionA Cloud
 *
 * 對齊：
 *   - `.autoflow/04-architecture/api/api-spec.md` §3 Devices（`/api/devices` / `/api/devices/:id` / connect / disconnect）
 *   - `.autoflow/03-design/flows/flow-offline-handling.md` §2（Device 新增 `remoteStatus`）
 *   - `.autoflow/04-architecture/TDD.md` §10.1（stores）
 *
 * 職責：
 *   - 保存當前使用者可見的裝置列表 + 當前選取裝置詳情
 *   - 接 `GET /api/devices` / `GET /api/devices/:id`（雛形後端透過 tunnel forward）
 *   - 提供 connect / disconnect 呼叫的 wrapper（純 API 呼叫；UI 實際狀態變更由 WS 推送）
 *
 * F6 範圍（雛形）：
 *   - 不做主動 WS 訂閱 — 待 F7/F8 接 `/ws/devices/events`
 *   - 後端 501 NOT_IMPLEMENTED 時 fallback 為空 list，不打擾 UI
 *   - `remoteStatus` 欄位若後端未提供，默認 `unknown`（避免誤顯示為 offline）
 *
 * 雛形安全/穩定性備註：
 *   - 所有錯誤以 `error: string` 記錄，不 throw，讓 UI 能用 `{ isLoading, error }` 處理
 *   - unmount 時不主動 abort（雛形保持簡單；F7/F8 改用 TanStack Query 或 SWR 時再處理）
 */

"use client";

import { create } from "zustand";

import { ApiError, api } from "@/lib/api";

/* -------------------------------------------------------------------------- */
/* Types — 對齊 api-spec.md §3 + flow-offline-handling.md §2                   */
/* -------------------------------------------------------------------------- */

/** 既有 USB / 硬體層級狀態（由 local agent 回報） */
export type DeviceHardwareStatus =
  | "detected"
  | "connecting"
  | "connected"
  | "flashing"
  | "inferencing"
  | "error"
  | "disconnected";

/** 遠端 tunnel 層級狀態（local agent ↔ 雲端） */
export type RemoteStatus = "online" | "offline" | "reconnecting" | "error" | "unknown";

/** 列表用的精簡裝置資訊 */
export interface DeviceSummary {
  id: string;
  name: string;
  /** 使用者自訂別名（後端或本機偏好皆可） */
  alias?: string;
  type: string;
  /** USB 層級狀態；離線時可能來自 cache */
  status: DeviceHardwareStatus;
  /** 遠端 tunnel 狀態（flow-offline-handling.md §2 新增） */
  remoteStatus: RemoteStatus;
  /** ISO 8601，最後心跳時間 */
  lastSeenAt?: string | null;
  firmwareVersion?: string | null;
  flashedModel?: string | null;
}

/** 裝置詳情（詳細頁用，比 Summary 多欄） */
export interface Device extends DeviceSummary {
  port?: string | null;
  hostName?: string | null;
  pairedAt?: string | null;
  errorMessage?: string | null;
}

/* -------------------------------------------------------------------------- */
/* 後端 snake_case ⇄ 前端 camelCase 正規化                                     */
/* -------------------------------------------------------------------------- */

/**
 * 把後端回傳的裝置物件正規化成前端型別。
 * - 接受 snake_case / camelCase 兩種形狀
 * - 對缺欄位寬容：`remoteStatus` 預設 `unknown`（而非 offline，避免誤判）
 */
function normalizeDevice(raw: unknown): Device {
  const r = (raw ?? {}) as Record<string, unknown>;
  const pick = <T = unknown>(...keys: string[]): T | undefined => {
    for (const k of keys) {
      if (r[k] !== undefined && r[k] !== null) return r[k] as T;
    }
    return undefined;
  };
  return {
    id: String(pick<string>("id") ?? ""),
    name: String(pick<string>("name") ?? pick<string>("device_name") ?? ""),
    alias: pick<string>("alias") ?? undefined,
    type: String(pick<string>("type", "device_type") ?? ""),
    status: (pick<string>("status") as DeviceHardwareStatus) ?? "disconnected",
    remoteStatus:
      (pick<string>("remote_status", "remoteStatus") as RemoteStatus) ?? "unknown",
    lastSeenAt: pick<string>("last_seen_at", "lastSeenAt") ?? null,
    firmwareVersion:
      pick<string>("firmware_version", "firmwareVersion") ?? null,
    flashedModel: pick<string>("flashed_model", "flashedModel") ?? null,
    port: pick<string>("port") ?? null,
    hostName: pick<string>("host_name", "hostName") ?? null,
    pairedAt: pick<string>("paired_at", "pairedAt") ?? null,
    errorMessage: pick<string>("error_message", "errorMessage") ?? null,
  };
}

/* -------------------------------------------------------------------------- */
/* Store                                                                      */
/* -------------------------------------------------------------------------- */

interface DeviceState {
  devices: DeviceSummary[];
  selectedDevice: Device | null;
  isLoading: boolean;
  /** 連線中的裝置 id（UI 顯示 button spinner）；不使用就是 null */
  connectingId: string | null;
  disconnectingId: string | null;
  error: string | null;

  /** 呼叫 `GET /api/devices` */
  fetchDevices: () => Promise<void>;
  /** 呼叫 `GET /api/devices/:id` */
  fetchDevice: (id: string) => Promise<void>;
  /** 呼叫 `POST /api/devices/:id/connect` */
  connectDevice: (id: string) => Promise<boolean>;
  /** 呼叫 `POST /api/devices/:id/disconnect` */
  disconnectDevice: (id: string) => Promise<boolean>;
  /** 測試 / 雛形用：直接塞 list */
  _setDevices: (devices: DeviceSummary[]) => void;
  /** 測試 / 雛形用：直接塞 selected */
  _setSelected: (device: Device | null) => void;
}

export const useDeviceStore = create<DeviceState>()((set) => ({
  devices: [],
  selectedDevice: null,
  isLoading: false,
  connectingId: null,
  disconnectingId: null,
  error: null,

  fetchDevices: async () => {
    set({ isLoading: true, error: null });
    try {
      const raw = await api.get<unknown[]>("/api/devices");
      const devices = Array.isArray(raw) ? raw.map(normalizeDevice) : [];
      set({ devices, isLoading: false });
    } catch (err) {
      // 雛形後端 501 / 無 tunnel 時不當嚴重錯誤，給空 list
      if (err instanceof ApiError && (err.code === "NOT_IMPLEMENTED" || err.code === "TUNNEL_DISCONNECTED")) {
        set({ devices: [], isLoading: false, error: null });
        return;
      }
      const message = err instanceof Error ? err.message : String(err);
      set({ isLoading: false, error: message });
    }
  },

  fetchDevice: async (id) => {
    set({ isLoading: true, error: null });
    try {
      const raw = await api.get<unknown>(`/api/devices/${encodeURIComponent(id)}`);
      set({ selectedDevice: normalizeDevice(raw), isLoading: false });
    } catch (err) {
      if (err instanceof ApiError && err.code === "NOT_IMPLEMENTED") {
        // 雛形後端未實作 — UI 退回 list 上的最後一筆或顯示 "離線 cache"
        set({ isLoading: false, error: null });
        return;
      }
      const message = err instanceof Error ? err.message : String(err);
      set({ isLoading: false, error: message });
    }
  },

  connectDevice: async (id) => {
    set({ connectingId: id, error: null });
    try {
      await api.post(`/api/devices/${encodeURIComponent(id)}/connect`);
      set({ connectingId: null });
      return true;
    } catch (err) {
      const message = err instanceof Error ? err.message : String(err);
      set({ connectingId: null, error: message });
      return false;
    }
  },

  disconnectDevice: async (id) => {
    set({ disconnectingId: id, error: null });
    try {
      await api.post(`/api/devices/${encodeURIComponent(id)}/disconnect`);
      set({ disconnectingId: null });
      return true;
    } catch (err) {
      const message = err instanceof Error ? err.message : String(err);
      set({ disconnectingId: null, error: message });
      return false;
    }
  },

  _setDevices: (devices) => set({ devices }),
  _setSelected: (selectedDevice) => set({ selectedDevice }),
}));