export const MARKET_REQUEST_SNAPSHOT_ATTRIBUTE =
  "data-sces-market-request-snapshot";
const MARKET_SEARCH_ENDPOINT_PATH = "/gw/api/gsearch/search_for_author_square";

export interface MarketListRequestSnapshot {
  body?: string;
  headers?: Record<string, string>;
  method: string;
  url: string;
}

export function readMarketListRequestSnapshot(
  document: Document
): MarketListRequestSnapshot | null {
  const serializedSnapshot = document.documentElement.getAttribute(
    MARKET_REQUEST_SNAPSHOT_ATTRIBUTE
  );
  if (!serializedSnapshot) {
    return readMarketListRequestSnapshotFromPageState(document);
  }

  try {
    const parsedSnapshot = normalizeMarketListRequestSnapshot(
      JSON.parse(serializedSnapshot)
    );
    if (!parsedSnapshot) {
      return readMarketListRequestSnapshotFromPageState(document);
    }

    return parsedSnapshot;
  } catch {
    return readMarketListRequestSnapshotFromPageState(document);
  }
}

export function writeMarketListRequestSnapshot(
  document: Document,
  snapshot: MarketListRequestSnapshot
): void {
  document.documentElement.setAttribute(
    MARKET_REQUEST_SNAPSHOT_ATTRIBUTE,
    JSON.stringify(snapshot)
  );
}

function isMarketListRequestSnapshot(
  value: unknown
): value is MarketListRequestSnapshot {
  if (!value || typeof value !== "object") {
    return false;
  }

  const candidate = value as Partial<MarketListRequestSnapshot>;
  return (
    typeof candidate.method === "string" &&
    typeof candidate.url === "string" &&
    (!("body" in candidate) || typeof candidate.body === "string") &&
    (!("headers" in candidate) || isStringRecord(candidate.headers))
  );
}

function normalizeMarketListRequestSnapshot(
  value: unknown
): MarketListRequestSnapshot | null {
  if (!value || typeof value !== "object") {
    return null;
  }

  const candidate = value as Partial<MarketListRequestSnapshot> & {
    headers?: Record<string, unknown>;
  };
  const normalizedSnapshot: Partial<MarketListRequestSnapshot> = {
    body: typeof candidate.body === "string" ? candidate.body : undefined,
    method: typeof candidate.method === "string" ? candidate.method : undefined,
    url: typeof candidate.url === "string" ? candidate.url : undefined
  };

  if (candidate.headers && typeof candidate.headers === "object") {
    normalizedSnapshot.headers = Object.fromEntries(
      Object.entries(candidate.headers)
        .filter(([, entry]) =>
          ["string", "number", "boolean"].includes(typeof entry)
        )
        .map(([key, entry]) => [key, String(entry)])
    );
  }

  return isMarketListRequestSnapshot(normalizedSnapshot)
    ? normalizedSnapshot
    : null;
}

function isStringRecord(value: unknown): value is Record<string, string> {
  if (!value || typeof value !== "object") {
    return false;
  }

  return Object.values(value).every((entry) => typeof entry === "string");
}

function readMarketListRequestSnapshotFromPageState(
  document: Document
): MarketListRequestSnapshot | null {
  const reqParams = findMarketReqParams(document);
  if (!reqParams) {
    return null;
  }

  return {
    body: JSON.stringify(reqParams),
    method: "POST",
    url: buildMarketSearchUrl(document)
  };
}

function findMarketReqParams(document: Document): Record<string, unknown> | null {
  const marketRoot = document.querySelector(".base-author-list") as
    | (Element & {
        __vue__?: {
          _setupState?: Record<string, unknown>;
        };
      })
    | null;
  const setupState = marketRoot?.__vue__?._setupState;
  if (!setupState) {
    return null;
  }

  const queue: unknown[] = Object.values(setupState);
  while (queue.length > 0) {
    const current = unwrapVueRef(queue.shift());
    if (!isRecord(current)) {
      continue;
    }

    const reqParams = unwrapVueRef(current.reqParams);
    if (isRecord(reqParams)) {
      return reqParams;
    }

    Object.values(current).forEach((value) => {
      queue.push(value);
    });
  }

  return null;
}

function buildMarketSearchUrl(document: Document): string {
  if (
    document.location?.origin &&
    document.location.origin !== "null" &&
    document.location.origin !== "about:blank"
  ) {
    return document.location.origin.includes("xingtu.cn")
      ? MARKET_SEARCH_ENDPOINT_PATH
      : new URL(MARKET_SEARCH_ENDPOINT_PATH, document.location.origin).toString();
  }

  return MARKET_SEARCH_ENDPOINT_PATH;
}

function unwrapVueRef(value: unknown): unknown {
  if (isRecord(value) && "value" in value) {
    return value.value;
  }

  return value;
}

function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === "object" && value !== null;
}