"use client";

import { useEffect, useState } from "react";
import { useRouter } from "next/navigation";
import { Loader2, X, MapPin, Sprout } from "lucide-react";

type SiteOption = { id: string; name: string; taken: boolean };

// Book an invoice line that has no matching plant item to a SITE instead.
//
// One container per site: sites another line has already taken are listed but disabled,
// so the outstanding containers spread across sites rather than piling onto the first.
// Clearing frees the site again. Booking to a site accounts for the line without
// creating income, because no machine exists to carry it.
export function SiteBookingSelect({
  lineId,
  value,
}: {
  lineId: string;
  value: string;
}) {
  const router = useRouter();
  const [options, setOptions] = useState<SiteOption[] | null>(null);
  const [current, setCurrent] = useState(value);
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    setCurrent(value);
  }, [value]);

  useEffect(() => {
    let alive = true;
    fetch(`/api/invoice-lines/${lineId}/site-options`, { cache: "no-store" })
      .then((r) => r.json())
      .then((d) => {
        if (alive && d.ok) setOptions(d.options);
      })
      .catch(() => {
        if (alive) setOptions([]);
      });
    return () => {
      alive = false;
    };
  }, [lineId]);

  async function book(payload: Record<string, unknown>, optimistic: string) {
    setBusy(true);
    setError(null);
    const previous = current;
    setCurrent(optimistic);
    try {
      const res = await fetch(`/api/invoice-lines/${lineId}/book`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(payload),
      });
      const data = await res.json().catch(() => ({ ok: false, error: "Unexpected response" }));
      if (!data.ok) {
        setCurrent(previous);
        setError(data.error || "Could not book it");
      } else {
        router.refresh();
      }
    } catch {
      setCurrent(previous);
      setError("Could not reach the server");
    } finally {
      setBusy(false);
    }
  }

  if (options === null) return null;

  const currentName = options.find((o) => o.id === current)?.name;

  return (
    <div className="min-w-[200px]">
      <label className="sr-only" htmlFor={`site-${lineId}`}>
        Book this line to a site
      </label>
      <div className="flex items-center gap-2">
        <select
          id={`site-${lineId}`}
          value={current}
          disabled={busy}
          onChange={(e) => {
            const v = e.target.value;
            book(v ? { siteId: v } : { clear: true }, v);
          }}
          className={`min-h-[44px] w-full rounded-lg border px-2 text-sm transition focus:outline-none focus:border-[#30638E] disabled:opacity-60 ${
            current
              ? "border-[#EDAE49]/40 bg-[#EDAE49]/10 text-[#8a6420] dark:text-[#EDAE49]"
              : "border-gray-200 dark:border-white/10 bg-white dark:bg-white/5"
          }`}
        >
          <option value="">— Book to a site —</option>
          {options.map((o) => (
            <option key={o.id} value={o.id} disabled={o.taken && o.id !== current}>
              {o.name}
              {o.taken && o.id !== current ? " — already has one" : ""}
            </option>
          ))}
        </select>
        {busy && <Loader2 className="w-4 h-4 animate-spin text-[#00798C] shrink-0" aria-label="Saving" />}
        {current && !busy && (
          <button
            type="button"
            onClick={() => book({ clear: true }, "")}
            aria-label="Remove the site booking"
            className="grid place-items-center w-11 h-11 rounded-lg text-gray-500 hover:bg-gray-100 dark:hover:bg-white/5 transition shrink-0"
          >
            <X className="w-4 h-4" />
          </button>
        )}
      </div>

      {currentName && (
        <p className="mt-1 flex items-center gap-1.5 text-xs text-[#8a6420] dark:text-[#EDAE49]">
          <MapPin className="w-3 h-3 shrink-0" />
          Booked to {currentName} — no income posted (no machine)
        </p>
      )}

      {error && <p className="mt-1 text-xs text-[#D1495B]">{error}</p>}
    </div>
  );
}

export function SiteBookingLegend() {
  return (
    <p className="flex items-center gap-1.5 text-xs text-gray-500 dark:text-gray-400">
      <Sprout className="w-3.5 h-3.5 shrink-0" />
      A site booking accounts for a line that matches no plant item. It posts no income —
      there is no machine to carry it — and each site takes one container.
    </p>
  );
}