import "server-only";
import { createHash, randomBytes } from "node:crypto";
import { admin } from "@/lib/supabase";

const clean = (value: unknown) =>
  String(value ?? "")
    .replace(/[\u0000-\u001f\u007f-\u009f\u202a-\u202e\u2066-\u2069]/gu, " ")
    .slice(0, 80);

export type ModeratorApplicationResult =
  | { ok: true; url: string }
  | { ok: false; message: string };

/**
 * Creates a moderator application for a confirmed platform identity (Telegram
 * or Discord user verified by the caller). The applicant still has to open the
 * returned link while signed in to the matching MineGeo account.
 */
export async function createModeratorApplication(input: {
  platform: "telegram" | "discord";
  platformUserId: string;
  platformUsername?: string | undefined;
  requestedUsername: string;
  origin: string;
}): Promise<ModeratorApplicationResult> {
  const username = input.requestedUsername.trim().toLowerCase();
  if (!/^[a-z0-9_]{3,32}$/.test(username))
    return {
      ok: false,
      message:
        "Use your MineGeo username (3–32 letters, numbers or underscores). Set it in MineGeo settings first.",
    };
  const database = admin();
  const { data: allowed, error: rateError } = await database.rpc("check_rate", {
    p_key: `mod-apply:${input.platform}:${input.platformUserId}`,
    p_limit: 5,
    p_seconds: 3600,
  });
  if (rateError || !allowed)
    return { ok: false, message: "Too many attempts. Try again later." };
  const { data: profile, error } = await database
    .from("profiles")
    .select("id,role,account_status")
    .eq("username", username)
    .maybeSingle();
  if (error) return { ok: false, message: "MineGeo is unavailable. Try again later." };
  if (!profile || profile.account_status !== "active")
    return {
      ok: false,
      message: "MineGeo username not found. Check the username in your account settings.",
    };
  if (profile.role !== "contributor")
    return { ok: false, message: "This account already has staff permissions." };
  const { data: existing } = await database
    .from("moderator_applications")
    .select("id")
    .eq("platform", input.platform)
    .eq("platform_user_id", input.platformUserId)
    .eq("status", "pending")
    .limit(1);
  if (existing?.length)
    return { ok: false, message: "You already have an application waiting for review." };
  const token = randomBytes(32).toString("hex");
  const hash = createHash("sha256").update(token).digest("hex");
  const insert = await database.from("moderator_applications").insert({
    platform: input.platform,
    platform_user_id: input.platformUserId,
    platform_username: clean(input.platformUsername),
    requested_username: username,
    confirmation_hash: hash,
  });
  if (insert.error) {
    console.error("Moderator application insert failed", insert.error);
    return { ok: false, message: "MineGeo is unavailable. Try again later." };
  }
  return {
    ok: true,
    url: `${new URL(input.origin).origin}/moderator-application/${token}`,
  };
}