"use client";
import { useEffect, useState } from "react";
import { useSnap } from "@/lib/client";
import { Field, LiveRegion } from "@/components/ui";
import { PRICES } from "@/lib/plan";

/* Settings › Plan. Admin only, and only once plans are live.
 *
 * Numbers and short labels, no selling: the plan's name, where it stands, the staff count against
 * the ceiling when there is one, what the hosted backups keep, and the billing contact. Three
 * things to do: ask for an invoice, which emails the owner and nothing more; pay by card, which
 * leaves for a page Stripe hosts and appears only when the server has Stripe keys (`cardsOn`) and
 * the room is not grandfathered; and download the backup, which is the same file Data offers and is
 * here because a room deciding whether to pay should have its way out beside the button. */
const STATE_WORDS: Record<string, string> = {
  grandfathered: "Free · everything included, for good",
  free: "Free",
  trial: "Trial",
  active: "Paid",
  grace: "Ended · still writable",
  read_only: "Read-only",
};

export default function PlanTab() {
  const { s, mutate } = useSnap();
  const p = s.plan;
  const cardsOn = (s.plan as { cardsOn?: boolean }).cardsOn === true;
  const card = (s.plan as { card?: boolean }).card === true;
  const [email, setEmail] = useState(p.billingEmail);
  const [want, setWant] = useState<"hosted_facility" | "health_service">("hosted_facility");
  const [msg, setMsg] = useState("");
  const [busy, setBusy] = useState("");
  const fmt = (iso: string | null) => iso ? new Date(iso).toLocaleDateString("en-AU", { day: "numeric", month: "short", year: "numeric" }) : "—";

  // Back from Stripe: ?card=ok or ?card=cancelled, said once and taken off the address.
  useEffect(() => {
    const q = new URLSearchParams(window.location.search);
    const back = q.get("card");
    if (!back) return;
    if (back === "ok") setMsg("Payment set up. The plan updates when Stripe confirms it — a minute at most.");
    else if (back === "cancelled") setMsg("Card payment cancelled. Nothing was charged.");
    q.delete("card");
    const rest = q.toString();
    window.history.replaceState(null, "", window.location.pathname + (rest ? `?${rest}` : ""));
  }, []);

  const row = (k: string, v: React.ReactNode) => (
    <div style={{ display: "grid", gridTemplateColumns: "160px 1fr", borderBottom: "1px solid var(--color-divider)", fontSize: 13 }}>
      <div style={{ padding: "10px 12px", fontSize: 11, fontWeight: 700, letterSpacing: "0.06em", textTransform: "uppercase", color: "var(--color-neutral-600)", background: "var(--color-surface)" }}>{k}</div>
      <div style={{ padding: "10px 12px", fontVariantNumeric: "tabular-nums" }}>{v}</div>
    </div>
  );

  async function run(op: "plan.billing" | "plan.invoice", payload: Record<string, unknown>, done: string) {
    setBusy(op); setMsg("");
    const r = await mutate(op, payload);
    setBusy("");
    setMsg(r.ok ? done : r.error);
  }

  /** Checkout or the Billing Portal: both answer a URL to leave for. */
  async function stripeGo(kind: "checkout" | "portal") {
    setBusy(kind); setMsg("");
    try {
      const r = await fetch(`/api/billing/${kind}`, { method: "POST", headers: { "content-type": "application/json" }, body: "{}" });
      const j = (await r.json().catch(() => ({}))) as { url?: string; error?: string };
      if (r.ok && j.url) { window.location.assign(j.url); return; }
      setMsg(j.error || "Could not reach the payment page.");
    } catch {
      setMsg("Could not reach the payment page.");
    }
    setBusy("");
  }

  const ends = p.state === "trial" ? "Trial ends" : p.state === "active" ? "Paid until" : p.state === "grace" ? "Writable until" : null;
  const paidOrTrial = p.state === "active" || p.state === "trial";
  // The card button: a room that could buy (free, trial, grace, read-only) and is not already
  // paying by card. A card-backed room gets Manage card instead.
  const showPay = cardsOn && !p.grandfathered && !card && p.state !== "active";
  const showManage = cardsOn && !p.grandfathered && card;

  return (
    <>
      <div className="sec" style={{ marginTop: "var(--space-6)" }}>Plan</div>
      <div style={{ fontFamily: "var(--font-heading)", fontWeight: 800, fontSize: 24, letterSpacing: "-0.02em", marginTop: "var(--space-3)" }}>{p.label}</div>
      <div style={{ border: "2px solid var(--color-text)", marginTop: "var(--space-3)", maxWidth: 640 }}>
        {row("Status", <b style={{ color: p.readOnly ? "var(--color-accent-700)" : undefined }}>{STATE_WORDS[p.state] || p.state}{p.state === "trial" && p.daysLeft !== null ? ` · ${p.daysLeft} days left` : ""}{p.state === "grace" && p.graceDaysLeft !== null ? ` · ${p.graceDaysLeft} days` : ""}</b>)}
        {row("Staff records", p.maxStaff === null ? String(p.staff) : `${p.staff} of ${p.maxStaff}`)}
        {row("Backups", `Nightly · ${p.backupDays} days`)}
        {ends && row(ends, fmt(p.state === "grace" ? p.graceEndsAt : p.endsAt))}
        {card && row("Paid by", "Card · monthly")}
        {p.org && row("Health service", p.org.name)}
        {row("Billing contact", p.billingEmail || "—")}
        {p.invoicer && row("Invoiced by", p.invoicer)}
      </div>

      {p.readOnly && (
        <div style={{ fontSize: 13, marginTop: "var(--space-3)", maxWidth: 640, lineHeight: 1.6 }}>
          Reports, exports and the backup still work. Writes start again when a payment is recorded.
        </div>
      )}

      {!p.grandfathered && (
        <>
          <div className="sec" style={{ marginTop: "var(--space-6)" }}>{cardsOn ? "Invoice or card" : "Invoice"}</div>
          <div className="tc-grid" style={{ display: "grid", gridTemplateColumns: "1fr 1fr", gap: "var(--space-3)", marginTop: "var(--space-3)", maxWidth: 640 }}>
            <Field label="Billing contact" hint="Where the invoice goes.">{(c) => <input {...c} className="input" type="email" autoComplete="email" value={email} onChange={(e) => setEmail(e.target.value)} />}</Field>
            <Field label="Plan">{(c) => (
              <select {...c} className="input" value={want} onChange={(e) => setWant(e.target.value as typeof want)}>
                <option value="hosted_facility">Hosted Facility · annual</option>
                <option value="health_service">Health Service · annual</option>
              </select>
            )}</Field>
          </div>
          <div style={{ display: "flex", gap: "var(--space-2)", marginTop: "var(--space-3)", flexWrap: "wrap", alignItems: "center" }}>
            <button className="btn btn-primary" disabled={!!busy || !email.trim()} onClick={() => run("plan.invoice", { email: email.trim(), plan: want }, "Requested. The invoice comes by email.")}>{busy === "plan.invoice" ? "Sending…" : "Request an invoice"}</button>
            {showPay && (
              <>
                <button className="btn btn-secondary" disabled={!!busy} onClick={() => stripeGo("checkout")}>{busy === "checkout" ? "Opening…" : "Pay by card"}</button>
                <span style={{ fontSize: 12, color: "var(--color-neutral-700)", fontVariantNumeric: "tabular-nums" }}>Hosted Facility · ${PRICES.hostedMonthly} a month, ex GST</span>
              </>
            )}
            {showManage && <button className="btn btn-secondary" disabled={!!busy} onClick={() => stripeGo("portal")}>{busy === "portal" ? "Opening…" : "Manage card"}</button>}
            <button className="btn btn-secondary" disabled={!!busy || email.trim() === p.billingEmail} onClick={() => run("plan.billing", { email: email.trim() }, "Saved.")}>Save contact</button>
            <a className="btn btn-ghost" href="/api/backup" download>Download backup</a>
          </div>
          {paidOrTrial && !card && <div style={{ fontSize: 12, color: "var(--color-neutral-700)", marginTop: "var(--space-2)" }}>A renewal invoice is requested the same way.</div>}
        </>
      )}
      {p.grandfathered && (
        <div style={{ display: "flex", gap: "var(--space-2)", marginTop: "var(--space-3)", flexWrap: "wrap" }}>
          <a className="btn btn-ghost" href="/api/backup" download>Download backup</a>
        </div>
      )}
      <LiveRegion msg={msg} style={{ fontSize: 12, color: "var(--color-accent-700)", fontWeight: 600, marginTop: "var(--space-2)" }} />
    </>
  );
}