import { PUBLIC_DOMAIN } from "$env/static/public";
import { decode } from "$lib/bip21";
import { auth, get, isLiquid, post, sats } from "$lib/utils";
import { redirect } from "@sveltejs/kit";

let validatePromise: Promise<typeof import("bitcoin-address-validation")> | undefined;
const loadValidate = () => (validatePromise ||= import("bitcoin-address-validation"));

export default async (s, host, cookies) => {
  if (!s) return;
  let t = s.trim();
  let amount;
  let invoice;
  let user;
  const aid = cookies.get("aid");

  if (t.startsWith("ark") || t.startsWith("tark")) redirect(303, `/send/ark/${t}${aid ? `?aid=${aid}` : ""}`);

  if (t.startsWith("http")) redirect(303, t);
  if (t.startsWith(host)) redirect(303, `http://${t}`);

  if (t.includes("lightning=")) {
    const url = new URL(t);
    const params = new URLSearchParams(url.search);
    t = params.get("lightning");
  }

  if (t.startsWith("lightning:")) t = t.replace("lightning:", "");
  if (t.includes("@") && t.split("@").pop() === PUBLIC_DOMAIN) t = t.split("@")[0];
  if (t.includes("@") && t.includes(".")) {
    try {
      t = await get(`/encode?address=${t}`);
    } catch {}
  }

  if (t.toLowerCase().startsWith("nostr:")) {
    t = t.split(":")[1];
  }

  if (["note", "nevent"].some((p) => t.startsWith(p))) redirect(303, `/e/${t}`);
  if (["nprofile", "npub"].some((p) => t.startsWith(p))) redirect(303, `/${t}`);

  // bitcoin
  if (t.toLowerCase().startsWith("bitcoin:") || t.toLowerCase().startsWith("liquidnetwork:")) {
    const { address: addr, options } = decode(t);
    amount = options.amount;

    if (options.ark) {
      let r = `/send/ark/${options.ark}`;
      if (amount) r += `/${Math.round(Number(amount) * sats)}`;
      redirect(303, r);
    }

    t = addr;
  }

  const { validate } = await loadValidate();
  if (validate(t) || isLiquid(t) || t.startsWith("bcrt1")) {
    let r = `/send/bitcoin/${t}`;
    if (amount) r += `/${Math.round(amount * sats)}`;
    redirect(303, r);
  }

  // lightning
  if (t.toLowerCase().startsWith("lightning:")) t = t.toLowerCase().replace("lightning:", "");
  if (t.toLowerCase().startsWith("lnurl")) redirect(303, `/ln/${t}`);
  if (t.includes(":")) t = t.split(":")[1];

  if (t.toLowerCase().startsWith("lnr")) {
    const { iid } = await post("/sendinvoice", { invreq: t }, auth(cookies));
    invoice = { id: iid };
  } else if (t.toLowerCase().startsWith("ln")) {
    try {
      const aid = cookies.get("aid");
      invoice = await get(`/invoice/${t}`);
      if (invoice.user.username === "mint") throw new Error("mint payment");
      if (aid && aid !== invoice.aid) throw new Error("cross-account");
    } catch {
      if (t.toLowerCase().startsWith("lno")) {
        const { offer_amount_msat: a } = await get(`/decode/${t}`);
        if (a) ({ invoice: t } = await post("/fetchinvoice", { offer: t }));
      }
      redirect(303, `/send/lightning/${t}`);
    }
  }

  if (invoice) redirect(303, `/invoice/${invoice.id}`);

  if (t.match(/^🥜([\uFE00-\uFE0F]|[\uE0100-\uE01EF]+)$/)) {
    t = (Array.from(t) as string[])
      .slice(1)
      .map((char: string) => {
        const codePoint = char.codePointAt(0)!;

        // Handle Variation Selectors (VS1-VS16): U+FE00 to U+FE0F
        if (codePoint >= 0xfe00 && codePoint <= 0xfe0f) {
          const byteValue = codePoint - 0xfe00; // Maps FE00->0, FE01->1, ..., FE0F->15
          return String.fromCharCode(byteValue);
        }

        // Handle Variation Selectors Supplement (VS17-VS256): U+E0100 to U+E01EF
        if (codePoint >= 0xe0100 && codePoint <= 0xe01ef) {
          const byteValue = codePoint - 0xe0100 + 16; // Maps E0100->16, E0101->17, ..., E01EF->255
          return String.fromCharCode(byteValue);
        }
      })
      .join("");
  }

  if (t.startsWith("cashu")) {
    const { id } = await post("/cash", { token: t });
    redirect(303, `/ecash/${id}`);
  }

  if (t.startsWith("creq")) redirect(303, `/send/ecash/${t}`);

  // user
  try {
    user = await get(`/users/${t.split("/")[0]}`);
    if (user.anon) user = null;
  } catch {}

  if (user) redirect(303, `/pay/${t}`);

  let fund;
  if (t.includes("/fund")) redirect(303, t.substring(t.indexOf("/fund")));

  try {
    fund = await get(`/fund/${t}`);
  } catch {}

  if (fund) redirect(303, `/send/fund/${t}`);
};