'use client';

import { useState } from 'react';
import type { PackageState, PlaneState, StateSnapshot } from '@/lib/game/state';
import { PLANE_TYPES } from '@/lib/game/catalog';
import { formatCash, formatDeadlineRelative } from '@/lib/format';
import { useGameAction } from '@/lib/useGameAction';
import type { HoverTarget } from './hoverTypes';

interface RightPaneProps {
  state: StateSnapshot | null;
  loading: boolean;
  // Push the full snapshot returned by an action endpoint into the shared shell state (v0.10.0),
  // so the pane updates on click without waiting for the next poll tick.
  applySnapshot: (snapshot: StateSnapshot) => void;
  // ISS-002 (v0.15.0): report row hovers to the shell so the map can highlight the plane or
  // the package's endpoint airports.
  onHover: (target: HoverTarget | null) => void;
  // ISS-008 (v0.17.0): report a failed action to the shell as an error toast — in ADDITION
  // to the inline pane error, which stays (both surfaces by design).
  onError?: (message: string) => void;
}

const planeName = (p: PlaneState): string => PLANE_TYPES[p.model]?.name ?? p.model;

// Packages occupying a plane's slots — 'loaded' cargo plus 'expired' cargo, which
// keeps its slot until it is abandoned or the plane lands at its destination.
export function slotsUsedFor(state: StateSnapshot, planeId: string): number {
  return state.packages.filter(
    (p) => p.planeId === planeId && (p.status === 'loaded' || p.status === 'expired'),
  ).length;
}

// Planes that can load `pkg` right now: GROUNDED at the package's origin with a
// free slot (capacity from the snapshot catalog). The Load button is enabled iff
// this list is non-empty; exactly one entry loads directly, several show a picker.
export function loadEligiblePlanes(state: StateSnapshot, pkg: PackageState): PlaneState[] {
  return state.planes.filter((p) => {
    if (p.status !== 'available') return false;
    if (p.locationIcao !== pkg.originIcao) return false;
    const capacity = state.catalog.find((e) => e.model === p.model)?.capacity ?? 0;
    return slotsUsedFor(state, p.id) < capacity;
  });
}

// Load controls for one open package: a single Load button when exactly one plane
// is eligible (it acts on that plane directly), a small plane picker + Load when
// several are, and a disabled button with the reason otherwise. Each row owns its
// selection in local state and defaults to the "Select a plane…" placeholder —
// never preselecting — so rows stay visibly independent (v0.10.1 pattern).
function LoadControls({
  pkg,
  eligible,
  busy,
  onLoad,
}: {
  pkg: PackageState;
  eligible: PlaneState[];
  busy: boolean;
  onLoad: (planeId: string) => void;
}) {
  const [selectedId, setSelectedId] = useState<string | null>(null);
  // The user's pick while it stays eligible, else nothing (placeholder).
  const effective = eligible.find((p) => p.id === selectedId) ?? null;

  if (eligible.length === 1) {
    return (
      <button
        type="button"
        data-testid={`load-${pkg.id}`}
        className="pane-btn"
        disabled={busy}
        onClick={() => onLoad(eligible[0].id)}
      >
        Load
      </button>
    );
  }

  return (
    <div className="dispatch-controls">
      <select
        data-testid={`load-plane-${pkg.id}`}
        aria-label={`Load plane for ${pkg.originName} to ${pkg.destName}`}
        value={effective?.id ?? ''}
        onChange={(e) => setSelectedId(e.target.value || null)}
      >
        <option value="">Select a plane…</option>
        {eligible.map((p) => (
          <option key={p.id} value={p.id}>
            {planeName(p)} — {p.locationIcao}
          </option>
        ))}
      </select>
      <button
        type="button"
        data-testid={`load-${pkg.id}`}
        className="pane-btn"
        disabled={busy || effective === null}
        onClick={() => {
          if (effective) onLoad(effective.id);
        }}
      >
        Load
      </button>
    </div>
  );
}

export default function RightPane({ state, loading, applySnapshot, onHover, onError }: RightPaneProps) {
  // ISS-021 (v0.20.0): shared action runner — busy gate, inline pane error + shell toast on
  // failure, full post-action snapshot pushed into the shared state on success.
  const { runAction, busy, actionError } = useGameAction(state, applySnapshot, onError);

  // Market picker selections — same "effective selection" pattern as LoadControls: the
  // user's pick while it stays valid, else a sensible default (first catalog entry / first plane).
  const [buyModelId, setBuyModelId] = useState<string | null>(null);
  const [sellPlaneId, setSellPlaneId] = useState<string | null>(null);
  const [refuelPlaneId, setRefuelPlaneId] = useState<string | null>(null);

  // ISS-023 (v0.21.0): the Relocate row moved to the left pane — it belongs with everything else
  // about our planes, not in the market. Its state + /api/airports fetch went with it.

  if (loading && !state) {
    return (
      <aside data-testid="right-pane" className="pane right-pane">
        <h2 className="pane-title">Jobs &amp; Market</h2>
        <p data-testid="right-loading" className="pane-muted">Loading…</p>
      </aside>
    );
  }
  if (!state) return null;

  const clockMs = state.simState.clockMs;
  const open = state.packages.filter((p) => p.status === 'open');

  const catalog = state.catalog;
  const buyEntry = catalog.find((e) => e.model === buyModelId) ?? catalog[0] ?? null;

  const grounded = state.planes.filter((p) => p.status === 'available');
  const sellPlane = state.planes.find((p) => p.id === sellPlaneId && p.status === 'available') ?? grounded[0] ?? null;
  const refuelable = grounded.filter((p) => p.fuel < p.maxFuel);
  const refuelPlane =
    state.planes.find((p) => p.id === refuelPlaneId && p.status === 'available' && p.fuel < p.maxFuel) ??
    refuelable[0] ??
    null;
  // Previews computed client-side from the snapshot's catalog + economy constants (v0.10.0).
  const sellEntry = sellPlane ? catalog.find((e) => e.model === sellPlane.model) : undefined;
  const sellPayout = sellEntry ? Math.round(sellEntry.price * state.sellFraction * 100) / 100 : null;
  const refuelCost = refuelPlane ? (refuelPlane.maxFuel - refuelPlane.fuel) * state.fuelPricePerL : null;

  return (
    <aside data-testid="right-pane" className="pane right-pane">
      <h2 className="pane-title">Jobs &amp; Market</h2>

      <section className="pane-section">
        <h3 className="pane-heading">Packages</h3>
        {open.length === 0 ? (
          <p className="pane-muted">No open packages.</p>
        ) : (
          <ul data-testid="open-packages" className="contract-list">
            {open.map((pkg) => {
              const eligible = loadEligiblePlanes(state, pkg);
              return (
                // ISS-002: hovering an open package highlights its two endpoint airports on the map.
                <li
                  key={pkg.id}
                  data-testid={`open-package-${pkg.id}`}
                  className="contract-row"
                  onMouseEnter={() => onHover({ kind: 'package', originIcao: pkg.originIcao, destIcao: pkg.destIcao })}
                  onMouseLeave={() => onHover(null)}
                >
                  <div className="contract-main">
                    <span className="contract-route">{pkg.originName} → {pkg.destName}</span>
                    {eligible.length > 0 ? (
                      <LoadControls
                        pkg={pkg}
                        eligible={eligible}
                        busy={busy}
                        onLoad={(planeId) => void runAction(`/api/packages/${pkg.id}/load`, { planeId })}
                      />
                    ) : (
                      <button type="button" data-testid={`load-${pkg.id}`} className="pane-btn" disabled>
                        Load
                      </button>
                    )}
                  </div>
                  <div className="contract-sub">
                    <span data-testid={`open-package-reward-${pkg.id}`}>{formatCash(pkg.reward)}</span>
                    <span>{pkg.cargoType} × {pkg.cargoCount}</span>
                    <span data-testid={`open-package-deadline-${pkg.id}`}>
                      {formatDeadlineRelative(pkg.deadlineSimTime, clockMs)}
                    </span>
                  </div>
                </li>
              );
            })}
          </ul>
        )}
      </section>

      {/* ISS-021 (v0.20.0): the On board section moved to the left pane (between Fleet and Time). */}

      <section className="pane-section">
        <h3 className="pane-heading">Market</h3>

        <div className="market-row">
          <select
            data-testid="market-buy-model"
            aria-label="Plane to buy"
            value={buyEntry?.model ?? ''}
            onChange={(e) => setBuyModelId(e.target.value || null)}
          >
            {catalog.map((e) => (
              <option key={e.model} value={e.model}>
                {e.label}
              </option>
            ))}
          </select>
          <span data-testid="market-buy-price" className="market-preview">
            {buyEntry ? formatCash(buyEntry.price) : ''}
          </span>
          <button
            type="button"
            data-testid="market-buy"
            className="pane-btn"
            disabled={busy || buyEntry === null}
            onClick={() => {
              if (buyEntry) void runAction('/api/market/buy-plane', { model: buyEntry.model });
            }}
          >
            Buy
          </button>
        </div>

        <div className="market-row">
          <select
            data-testid="market-sell-plane"
            aria-label="Plane to sell"
            value={sellPlane?.id ?? ''}
            onChange={(e) => setSellPlaneId(e.target.value || null)}
          >
            {grounded.map((p) => (
              <option key={p.id} value={p.id}>
                {planeName(p)} — {p.locationIcao}
              </option>
            ))}
          </select>
          <span data-testid="market-sell-payout" className="market-preview">
            {sellPayout !== null ? formatCash(sellPayout) : ''}
          </span>
          <button
            type="button"
            data-testid="market-sell"
            className="pane-btn"
            disabled={busy || sellPlane === null}
            onClick={() => {
              if (sellPlane) void runAction('/api/market/sell-plane', { planeId: sellPlane.id });
            }}
          >
            Sell
          </button>
        </div>

        <div className="market-row">
          {refuelable.length === 0 ? (
            <span data-testid="market-refuel-none" className="pane-muted">
              All tanks full.
            </span>
          ) : (
            <>
              <select
                data-testid="market-refuel-plane"
                aria-label="Plane to refuel"
                value={refuelPlane?.id ?? ''}
                onChange={(e) => setRefuelPlaneId(e.target.value || null)}
              >
                {refuelable.map((p) => (
                  <option key={p.id} value={p.id}>
                    {planeName(p)} — {Math.round(p.fuel)} / {p.maxFuel} L
                  </option>
                ))}
              </select>
              <span data-testid="market-refuel-cost" className="market-preview">
                {refuelCost !== null ? formatCash(refuelCost) : ''}
              </span>
            </>
          )}
          <button
            type="button"
            data-testid="market-refuel"
            className="pane-btn"
            disabled={busy || refuelPlane === null}
            onClick={() => {
              if (refuelPlane) void runAction(`/api/planes/${refuelPlane.id}/refuel`);
            }}
          >
            Refuel to full
          </button>
        </div>

        {/* ISS-023 (v0.21.0): the Relocate row moved to the left pane's "Relocate" section. */}
      </section>

      {actionError && <p data-testid="right-error" className="pane-error">{actionError}</p>}
    </aside>
  );
}