/**
 * @file prefs.ts
 * @description Tiny localStorage-backed preference store for Sagi (enabled +
 *   muted). Broadcasts changes via a window CustomEvent so the Settings toggle
 *   and the live widget stay in sync within the same tab without a reload.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */
/* =============================================================================
 * MODULE_GUIDE — extended in-file reference (comments only; safe to read, never executed)
 * =============================================================================
 * **Purpose:** Sagi is the optional on-screen mascot assistant — quips, intents, and lightweight event reactions layered above the dashboard chrome.
 *
 * ## Design constraints
 * - Local-first: no telemetry leaves the machine unless the user configures webhooks.
 * - Fail-safe hooks path on the server must never block Claude Code; UI mirrors that
 *   philosophy by degrading gracefully (empty states, stale badges, reconnect loops).
 * - Destructive flows stay behind explicit confirmation modals and server-side gates.
 * - Internationalization: user-visible strings belong in i18n JSON, not literals here.
 *
 * ## Remote data & SSH
 * Remote Data Sources let operators aggregate multiple machines. SSH entries describe
 * how to reach a peer dashboard; the global data scope (`dataScope.ts`) narrows every
 * scoped GET via `?sources=`. Health checks and import history surface in Settings.
 *
 * ## Public surface
 * - `SagiPos` — exported API; see TSDoc on the symbol for behavior.
 * - `sagiPrefs` — exported API; see TSDoc on the symbol for behavior.
 *
 * ## Testing pointers
 * - Prefer colocated `__tests__` with Vitest + Testing Library for UI.
 * - Server contract changes require `npm run test:server` and OpenAPI sync.
 * - MCP edits: `npm run mcp:typecheck` and `npm run mcp:build`.
 *
 * ## Related docs
 * - `ARCHITECTURE.md` — hooks → API → SQLite → WebSocket → UI pipeline.
 * - `docs/API.md` — REST reference.
 * - `.claude/skills/file-headers/` — mandatory `@author` header policy.
 * ============================================================================= */
/* -----------------------------------------------------------------------------
 * EXPORT CATALOG — quick index of symbols defined below (documentation only).
 * -----------------------------------------------------------------------------
 * **SagiPos**
 *   Part of this module's public contract. Downstream imports should treat
 *   the signature and return type as stable unless release notes say otherwise.
 *   When behavior changes, update the `@file` overview and relevant tests.
 *
 * **sagiPrefs**
 *   Part of this module's public contract. Downstream imports should treat
 *   the signature and return type as stable unless release notes say otherwise.
 *   When behavior changes, update the `@file` overview and relevant tests.
 *
 * ----------------------------------------------------------------------------- */

const ENABLED_KEY = "agent-dashboard-sagi-enabled";
const MUTED_KEY = "agent-dashboard-sagi-muted";
const POS_KEY = "agent-dashboard-sagi-pos";
const EVENT = "sagi:prefs";

/**
 * Persisted resting position, AssistiveTouch-style: the widget always docks to
 * the left or right edge, remembering its vertical offset. `y` is stored as a
 * fraction of the viewport height (0–1) so it survives window resizes.
 */
export interface SagiPos {
  side: "left" | "right";
  y: number;
}

function readBool(key: string, fallback: boolean): boolean {
  try {
    const v = localStorage.getItem(key);
    return v === null ? fallback : v === "true";
  } catch {
    return fallback;
  }
}

function writeBool(key: string, value: boolean): void {
  try {
    localStorage.setItem(key, String(value));
  } catch {
    // Ignore storage failures (private mode, quota) - prefs are best-effort.
  }
  try {
    window.dispatchEvent(new CustomEvent(EVENT));
  } catch {
    // SSR / non-DOM contexts: nothing to notify.
  }
}

function readPos(): SagiPos | null {
  try {
    const raw = localStorage.getItem(POS_KEY);
    if (!raw) return null;
    const p = JSON.parse(raw) as Partial<SagiPos>;
    if ((p.side === "left" || p.side === "right") && typeof p.y === "number") {
      return { side: p.side, y: Math.min(1, Math.max(0, p.y)) };
    }
    return null;
  } catch {
    return null;
  }
}

function writePos(pos: SagiPos): void {
  try {
    localStorage.setItem(POS_KEY, JSON.stringify(pos));
  } catch {
    // Ignore storage failures - position is best-effort.
  }
  // Note: intentionally does NOT dispatch the prefs event - position changes
  // are local to the widget and shouldn't churn the Settings toggle listeners.
}

export const sagiPrefs = {
  getEnabled: () => readBool(ENABLED_KEY, true),
  setEnabled: (v: boolean) => writeBool(ENABLED_KEY, v),
  getMuted: () => readBool(MUTED_KEY, false),
  setMuted: (v: boolean) => writeBool(MUTED_KEY, v),
  getPos: readPos,
  setPos: writePos,
  /** Subscribe to any pref change; returns an unsubscribe fn. */
  subscribe(handler: () => void): () => void {
    const listener = () => handler();
    window.addEventListener(EVENT, listener);
    // Also react to changes from other tabs.
    window.addEventListener("storage", listener);
    return () => {
      window.removeEventListener(EVENT, listener);
      window.removeEventListener("storage", listener);
    };
  },
};
