import type { Contract, PlayerState } from "@deadhead/schema";
import { useQuery } from "@tanstack/react-query";
import { useSearchParams } from "react-router";
import { useApi } from "../api/context";
import { useClock } from "../clock/clock";
import { Countdown } from "../components/Countdown";
import { cargoName, formatCredits, formatMillionKm, locationName, skillName } from "../format";
import { distanceAt } from "../game";
import { useLoadedPlayer } from "../state/actions";

export const locationBoardKey = (locationId: string) => ["board", "location", locationId] as const;

/** Skills a contract needs, e.g. "Heavy Cargo 2, Long Haul 1", or null. */
export function requirementsText(contract: Contract): string | null {
  const parts = [
    contract.requiredSkill
      ? `${skillName(contract.requiredSkill.skillId)} ${contract.requiredSkill.level}`
      : null,
    contract.requiredLongHaulLevel > 0 ? `Long Haul ${contract.requiredLongHaulLevel}` : null,
  ].filter((p): p is string => p !== null);
  return parts.length > 0 ? parts.join(", ") : null;
}

/**
 * The location the Contracts screen opens on: where the most recently arrived
 * idle ship is, otherwise Earth (CR-002).
 */
export function defaultBoardLocation(state: PlayerState): string {
  const idle = state.ships.filter((s) => s.status === "idle" && s.locationId);
  idle.sort((a, b) => b.lastArrivalAt - a.lastArrivalAt);
  return idle[0]?.locationId ?? "earth";
}

/** Freight markets of every discovered location, no bay needed (Steps 9.4, 10B.7). */
export function LocationBoards({ onSelect }: { onSelect?: (contract: Contract) => void }) {
  const state = useLoadedPlayer();
  // `?location=moon` (from the map or Fleet) selects that location.
  const [params, setParams] = useSearchParams();
  const discovered = state.locations.filter((l) => l.discovered).map((l) => l.id);
  const requested = params.get("location");
  const locationId =
    requested && discovered.includes(requested) ? requested : defaultBoardLocation(state);
  const idleAt = (id: string) =>
    state.ships.filter((s) => s.status === "idle" && s.locationId === id).length;

  return (
    <div className="space-y-3">
      <div role="group" aria-label="Location" className="flex flex-wrap gap-2">
        {discovered.map((id) => {
          const idle = idleAt(id);
          return (
            <button
              key={id}
              type="button"
              aria-pressed={id === locationId}
              onClick={() => setParams({ location: id }, { replace: true })}
              className="flex items-center gap-1.5 rounded-full border border-slate-700 px-3 py-1 text-sm aria-pressed:border-amber-400 aria-pressed:bg-amber-500/15 aria-pressed:text-amber-200"
            >
              {locationName(id)}
              {idle > 0 && (
                <span
                  aria-label={`${idle} idle ${idle === 1 ? "ship" : "ships"}`}
                  className="rounded-full bg-sky-500/25 px-1.5 text-xs tabular-nums text-sky-200"
                >
                  {idle}
                </span>
              )}
            </button>
          );
        })}
      </div>
      {idleAt(locationId) === 0 && (
        <p className="text-sm text-slate-400">
          No idle ships here. Deadhead one in from the Fleet screen to take these jobs.
        </p>
      )}
      <LocationBoard locationId={locationId} onSelect={onSelect} />
    </div>
  );
}

function LocationBoard({
  locationId,
  onSelect,
}: {
  locationId: string;
  onSelect?: (contract: Contract) => void;
}) {
  const api = useApi();
  const now = useClock((s) => s.now);
  const board = useQuery({
    queryKey: locationBoardKey(locationId),
    queryFn: () => api.call("getContractBoard", { locationId }),
  });

  if (board.isPending) return <p className="text-slate-400">Loading contracts…</p>;
  if (board.isError) {
    return (
      <div role="alert" className="text-red-400">
        Could not load contracts.{" "}
        <button type="button" className="underline" onClick={() => void board.refetch()}>
          Retry
        </button>
      </div>
    );
  }
  if (board.data.contracts.length === 0) {
    return (
      <p className="text-sm text-slate-400">No contracts left this period. Check back soon.</p>
    );
  }

  return (
    <ul className="space-y-2">
      {board.data.contracts.map((contract) => {
        const requirements = requirementsText(contract);
        return (
          <li key={contract.id} className="rounded-lg border border-slate-800 p-3">
            <div className="flex items-baseline justify-between gap-2">
              <span className="font-medium">
                {locationName(contract.originId)} → {locationName(contract.destinationId)}
                {contract.firstContact && (
                  <span className="ml-2 rounded bg-amber-500/20 px-1.5 py-0.5 text-xs text-amber-300">
                    First contact
                  </span>
                )}
              </span>
              <span className="font-semibold tabular-nums text-emerald-400">
                {formatCredits(contract.payout)}
              </span>
            </div>
            <div className="mt-1 text-sm text-slate-400">
              {cargoName(contract.cargoTypeId)}
              {contract.tier > 0 && ` (tier ${contract.tier})`} · {contract.massTonnes} t ·{" "}
              {formatMillionKm(distanceAt(contract.originId, contract.destinationId, now))}
            </div>
            <div className="mt-1 flex items-center justify-between gap-2 text-sm">
              <span className="text-slate-400">
                {requirements ? `Needs ${requirements}` : "No skills needed"} · expires in{" "}
                <Countdown to={contract.expiresAt} done="expired" />
              </span>
              {onSelect && (
                <button
                  type="button"
                  onClick={() => onSelect(contract)}
                  className="shrink-0 rounded-md bg-amber-500 px-3 py-1 font-semibold text-slate-950"
                >
                  Dispatch
                </button>
              )}
            </div>
          </li>
        );
      })}
    </ul>
  );
}