PolyWeather/frontend/components/dashboard/scan-terminal/market-scan-state.ts

import {
  buildStorageKey,
  readCachedPayload,
  writeCachedPayload,
} from "@/components/dashboard/scan-terminal/scan-terminal-cache";
import type { RemoteData } from "@/components/dashboard/scan-terminal/scan-terminal-client";
import type { CityDetail, MarketScan } from "@/lib/dashboard-types";
import { normalizeCityKey } from "./decision-utils";

const CITY_MARKET_SCAN_CACHE_PREFIX = "polyWeather_cityMarketScan_v3";
const CITY_MARKET_SCAN_CACHE_TTL_MS = 10 * 60 * 1000;

export type CityMarketScanStatus = "idle" | "loading" | "ready" | "failed";

export type CityMarketScanSnapshot =
  | { action: "reset"; cacheKey?: string }
  | { action: "success"; cacheKey: string; payload: MarketScan; shouldWriteCache?: boolean }
  | { action: "fetch"; cacheKey: string };

export function buildCityMarketScanCacheKey({
  detailCityName,
  localDate,
}: {
  detailCityName: string;
  localDate?: string | null;
}) {
  return buildStorageKey(CITY_MARKET_SCAN_CACHE_PREFIX, [
    normalizeCityKey(detailCityName),
    localDate || "",
    "full",
  ]);
}

export function readCachedCityMarketScan(cacheKey: string) {
  return readCachedPayload<MarketScan>(cacheKey, CITY_MARKET_SCAN_CACHE_TTL_MS);
}

export function writeCachedCityMarketScan(cacheKey: string, payload: MarketScan) {
  writeCachedPayload(cacheKey, payload);
}

export function resolveCityMarketScanSnapshot({
  detail,
  detailCityName,
  enabled,
}: {
  detail: CityDetail | null;
  detailCityName: string;
  enabled: boolean;
}): CityMarketScanSnapshot {
  if (!detail) return { action: "reset" };
  const cacheKey = buildCityMarketScanCacheKey({
    detailCityName,
    localDate: detail.local_date || "",
  });
  if (detail.market_scan) {
    return {
      action: "success",
      cacheKey,
      payload: detail.market_scan,
      shouldWriteCache: true,
    };
  }
  const cached = readCachedCityMarketScan(cacheKey);
  if (cached) {
    return {
      action: "success",
      cacheKey,
      payload: cached,
    };
  }
  return enabled ? { action: "fetch", cacheKey } : { action: "reset", cacheKey };
}

export function deriveCityMarketScanView({
  detailMarketScan,
  marketRemote,
}: {
  detailMarketScan?: MarketScan | null;
  marketRemote: RemoteData<MarketScan>;
}) {
  const previousMarketScan =
    marketRemote.status === "loading" || marketRemote.status === "error"
      ? marketRemote.previous ?? null
      : null;
  const marketScan =
    marketRemote.status === "success"
      ? marketRemote.data
      : previousMarketScan ?? detailMarketScan ?? null;
  const marketStatus: CityMarketScanStatus =
    marketRemote.status === "success"
      ? "ready"
      : marketRemote.status === "loading"
        ? "loading"
        : marketRemote.status === "error"
          ? marketScan
            ? "ready"
            : "failed"
          : "idle";

  return { marketScan, marketStatus };
}