"use server";

import { revalidateTag } from "next/cache";

import { readdirSync } from "fs";
import { join } from "path";

export async function refetchPlatform(
  platform: string
): Promise<{ count: number | null }> {
  // Validate platform against actual files to prevent path traversal
  const dir = join(process.cwd(), "lib", "followers");
  const validPlatforms = readdirSync(dir)
    .filter((f) => f.endsWith(".ts") && f !== "index.ts")
    .map((f) => f.replace(".ts", ""));

  if (!validPlatforms.includes(platform)) {
    throw new Error("Invalid platform");
  }

  let count: number | null = null;
  let tiktokProfile = null;

  try {
    const mod = await import(`@/lib/followers/${platform}`);
    const fns = Object.entries(mod).filter(
      ([, v]) => typeof v === "function"
    ) as [string, Function][];

    // Prefer function with "Count" or "Member" in name
    const countFn = fns.find(([name]) => /count|member/i.test(name));
    const fn = countFn || fns[0];

    if (fn) {
      const result = await fn[1]();
      if (typeof result === "number") {
        count = result;
      } else if (result === null) {
        count = null;
      } else if (
        result &&
        typeof result === "object" &&
        "followerCount" in result
      ) {
        count = result.followerCount;
        tiktokProfile = result;
      }
    }
  } catch (err) {
    console.error(`Failed to fetch ${platform}:`, err);
    throw new Error(`Failed to fetch ${platform}`);
  }

  // Update Redis cache
  try {
    const { getRedisClient } = await import("@/lib/redis");
    const redis = await getRedisClient();

    const cached = await redis.get("erika:follower_counts");
    const counts: Record<string, number | null> = cached
      ? JSON.parse(cached)
      : {};
    counts[platform] = count;
    await redis.set("erika:follower_counts", JSON.stringify(counts), { ex: 3600 });

    if (tiktokProfile) {
      await redis.set(
        "erika:tiktok_profile",
        JSON.stringify(tiktokProfile),
        { ex: 3600 }
      );
    }
  } catch {
    // Redis unavailable
  }

  // @ts-ignore
  revalidateTag("follower-counts-api");

  return { count };
}