import { FEED_BASE_URL } from "./env";
import { ensureFreshSession, refreshSession } from "./session-refresh";

// Text-post creation proxy. Two feed calls with the person's server-held feed
// token: create a public draft, then publish it with the same content. Neither
// the token nor the post text is logged.

export type CreatePostResult =
  | { ok: true; id: string; status: string | null }
  | { ok: false; status: 400 | 401 | 502; error: "sign_in" | "empty_post" | "post_failed" };

interface CreateOptions {
  fetchImpl?: typeof fetch;
  now?: number;
}

export const MAX_POST_LENGTH = 20_000;

function rec(v: unknown): Record<string, unknown> {
  return v && typeof v === "object" && !Array.isArray(v) ? (v as Record<string, unknown>) : {};
}

function readCreated(body: unknown): { id: string; status: string | null } | null {
  const root = rec(body);
  const data = rec(root.data);
  const post = rec(data.post);
  for (const v of [data.id, post.id, root.id]) {
    if ((typeof v === "string" && v) || typeof v === "number") {
      const status = [data.status, post.status, root.status].find((s) => typeof s === "string");
      return { id: String(v), status: (status as string | undefined) ?? null };
    }
  }
  return null;
}

function send(token: string, path: string, payload: unknown, doFetch: typeof fetch) {
  return doFetch(`${FEED_BASE_URL}${path}`, {
    method: "POST",
    headers: {
      Accept: "application/json",
      "Content-Type": "application/json",
      Authorization: `Bearer ${token}`,
    },
    body: JSON.stringify(payload),
  });
}

export async function createTextPost(
  sessionId: string | undefined,
  content: unknown,
  options: CreateOptions = {},
): Promise<CreatePostResult> {
  const signIn = { ok: false, status: 401, error: "sign_in" } as const;
  const failed = { ok: false, status: 502, error: "post_failed" } as const;
  const doFetch = options.fetchImpl ?? fetch;

  let session = await ensureFreshSession(sessionId, options);
  if (!session || !sessionId) return signIn;
  if (typeof content !== "string" || !content.trim() || content.length > MAX_POST_LENGTH) {
    return { ok: false, status: 400, error: "empty_post" };
  }

  // One call with a single refresh-and-retry on a 401 token rejection.
  const call = async (path: string, payload: unknown): Promise<Response | "sign_in"> => {
    let res = await send(session!.feedAccessToken, path, payload, doFetch);
    if (res.status === 401) {
      session = await refreshSession(sessionId, options);
      if (!session) return "sign_in";
      res = await send(session.feedAccessToken, path, payload, doFetch);
      if (res.status === 401) return "sign_in";
    }
    return res;
  };

  try {
    const created = await call("/api/v1/posts", {
      content,
      type: "text",
      status: "draft",
      visibility: "public",
    });
    if (created === "sign_in") return signIn;
    if (created.status !== 200 && created.status !== 201) return failed;
    const info = readCreated(await created.json().catch(() => null));
    if (!info) return failed;

    const published = await call(`/api/v1/posts/${encodeURIComponent(info.id)}/publish`, { content });
    if (published === "sign_in") return signIn;
    if (published.status < 200 || published.status > 299) return failed;
    return { ok: true, id: info.id, status: info.status };
  } catch {
    return failed;
  }
}