const OPENCLAW_3D_VIEWER_SESSION_PREFIX = "openclaw-3d-viewer:v1:";
const OPENCLAW_3D_VIEWER_SESSION_MAX_AGE_MS = 24 * 60 * 60 * 1000;

export type OpenClaw3DViewerSession = {
  messageId: string;
  viewMode: "product" | "packaging";
  explodeAmount: number;
  packagingExplodeAmount: number;
  selectedNodeName: string | null;
  selectedPackagingNodeName: string | null;
  updatedAt: number;
};

type ViewerSessionStorage = Pick<Storage, "getItem" | "setItem" | "removeItem">;

function getViewerSessionKey(chatId: string) {
  return `${OPENCLAW_3D_VIEWER_SESSION_PREFIX}${chatId}`;
}

function removeViewerSession(storage: ViewerSessionStorage, key: string) {
  try {
    storage.removeItem(key);
  } catch {
    // Storage can be unavailable under strict browser privacy policies.
  }
}

function normalizeExplodeAmount(value: unknown) {
  const amount = typeof value === "number" ? value : Number(value);
  if (!Number.isFinite(amount)) return 0;
  return Math.max(0, Math.min(1, amount));
}

export function readOpenClaw3DViewerSession(params: {
  storage: ViewerSessionStorage;
  chatId: string;
  now?: number;
}): OpenClaw3DViewerSession | null {
  const key = getViewerSessionKey(params.chatId);
  try {
    const raw = params.storage.getItem(key);
    if (!raw) return null;
    const value = JSON.parse(raw) as Record<string, unknown>;
    const messageId =
      typeof value.messageId === "string" ? value.messageId.trim() : "";
    const updatedAt = Number(value.updatedAt);
    const now = params.now ?? Date.now();
    if (
      !messageId ||
      !Number.isFinite(updatedAt) ||
      updatedAt <= 0 ||
      now - updatedAt > OPENCLAW_3D_VIEWER_SESSION_MAX_AGE_MS
    ) {
      removeViewerSession(params.storage, key);
      return null;
    }
    return {
      messageId,
      viewMode: value.viewMode === "packaging" ? "packaging" : "product",
      explodeAmount: normalizeExplodeAmount(
        value.productExplodeAmount ?? value.explodeAmount
      ),
      packagingExplodeAmount:
        value.packagingExplodeAmount === undefined
          ? 1
          : normalizeExplodeAmount(value.packagingExplodeAmount),
      selectedNodeName:
        typeof value.selectedNodeName === "string" &&
        value.selectedNodeName.trim()
          ? value.selectedNodeName.trim()
          : null,
      selectedPackagingNodeName:
        typeof value.selectedPackagingNodeName === "string" &&
        value.selectedPackagingNodeName.trim()
          ? value.selectedPackagingNodeName.trim()
          : null,
      updatedAt,
    };
  } catch {
    removeViewerSession(params.storage, key);
    return null;
  }
}

export function writeOpenClaw3DViewerSession(params: {
  storage: ViewerSessionStorage;
  chatId: string;
  messageId: string;
  explodeAmount: number;
  viewMode?: "product" | "packaging";
  packagingExplodeAmount?: number;
  selectedNodeName?: string | null;
  selectedPackagingNodeName?: string | null;
  now?: number;
}) {
  const messageId = params.messageId.trim();
  if (!messageId) return;
  try {
    params.storage.setItem(
      getViewerSessionKey(params.chatId),
      JSON.stringify({
        messageId,
        viewMode: params.viewMode || "product",
        explodeAmount: normalizeExplodeAmount(params.explodeAmount),
        packagingExplodeAmount:
          params.packagingExplodeAmount === undefined
            ? 1
            : normalizeExplodeAmount(params.packagingExplodeAmount),
        selectedNodeName: params.selectedNodeName?.trim() || null,
        selectedPackagingNodeName:
          params.selectedPackagingNodeName?.trim() || null,
        updatedAt: params.now ?? Date.now(),
      } satisfies OpenClaw3DViewerSession)
    );
  } catch {
    // Private browsing and storage policies may disable sessionStorage.
  }
}

export function clearOpenClaw3DViewerSession(params: {
  storage: ViewerSessionStorage;
  chatId: string;
  messageId: string;
}) {
  const current = readOpenClaw3DViewerSession({
    storage: params.storage,
    chatId: params.chatId,
  });
  if (current?.messageId !== params.messageId) return;
  removeViewerSession(params.storage, getViewerSessionKey(params.chatId));
}