import type { PlanningItemView, PlanningView } from "@batch-cooking/shared";
import { useDraggable } from "@dnd-kit/core";
import { useEffect, useRef, useState } from "react";
import { useTranslation } from "react-i18next";
import { apiClient } from "../../api/client";
import { BottomSheet } from "../../components/ui/BottomSheet";
import { useIsMobileViewport } from "../../lib/useIsMobileViewport";
import { collectLeftoverLines, dragIdForLeftover } from "./leftovers-basket";
import "./leftovers-basket.scss";

/**
 * The planning header's leftovers basket — an icon (with a count badge)
 * that opens a popover listing this week's still-available leftover pools:
 * one line per fresh planning item that cooked more than it needed, with
 * where it came from, how many portions are left, and a "jeter" button.
 *
 * Each line is also draggable (`@dnd-kit`, see {@link LeftoverLineCard})
 * onto a planning cell to serve part of its pool there — `PlanningPage`
 * owns the `DndContext` and the drop handling. Same conditional-mount +
 * outside-click-to-close pattern as `WeekNavigator`'s `CalendarPopover`.
 * The list is derived on every render from `planning` (see
 * {@link collectLeftoverLines}) rather than held in its own state, so a
 * discard or assignment elsewhere on the page is reflected here for free.
 *
 * On a phone this renders inside a {@link BottomSheet} instead of the
 * plain anchored `div` below — the fixed-width popover (`right: 0`, no
 * edge handling) used to render identically at every width, which could
 * push it partly or fully off a narrow screen (see the mobile/tablet UI
 * chantier's own audit — very plausibly *the* concrete cause of reported
 * "can't reach a button" complaints on mobile).
 */
export function LeftoversBasket({
  planning,
  onLeftoverDiscarded,
}: {
  planning: PlanningView | null;
  /** The updated item as returned by `PATCH .../discard-leftover` — the parent patches it into its planning state. */
  onLeftoverDiscarded: (item: PlanningItemView) => void;
}) {
  const { t } = useTranslation();
  const isMobile = useIsMobileViewport();
  const [isOpen, setIsOpen] = useState(false);
  const [discardingId, setDiscardingId] = useState<number | null>(null);
  const popoverRef = useRef<HTMLDivElement>(null);

  const lines = collectLeftoverLines(planning);

  useEffect(() => {
    // On mobile the BottomSheet branch below never attaches this ref (it's
    // a native <dialog> with its own tap-outside handling instead) —
    // `popoverRef.current` would just stay `null` and this would silently
    // no-op every time, harmless but pointless, so skip attaching the
    // listener at all in that case.
    if (!isOpen || isMobile) return;
    function handleClickOutside(e: MouseEvent) {
      if (popoverRef.current && !popoverRef.current.contains(e.target as Node)) {
        setIsOpen(false);
      }
    }
    document.addEventListener("mousedown", handleClickOutside);
    return () => document.removeEventListener("mousedown", handleClickOutside);
  }, [isOpen, isMobile]);

  async function discard(item: PlanningItemView) {
    setDiscardingId(item.id);
    try {
      const updated = await apiClient.discardLeftover(item.id);
      onLeftoverDiscarded(updated);
    } catch {
      // Leave the line in place — the user can retry. The error surface
      // here is intentionally minimal: nothing is lost by a failed discard.
    } finally {
      setDiscardingId(null);
    }
  }

  const listContent =
    lines.length === 0 ? (
      <p className="leftovers-basket__empty">{t("planning.leftovers.empty")}</p>
    ) : (
      <ul className="leftovers-basket__list">
        {lines.map(({ item, available }) => (
          <LeftoverLineCard
            key={item.id}
            item={item}
            available={available}
            isDiscarding={discardingId === item.id}
            onDiscard={() => void discard(item)}
          />
        ))}
      </ul>
    );

  return (
    <div className="leftovers-basket">
      <button
        type="button"
        className="leftovers-basket__toggle"
        onClick={() => setIsOpen((open) => !open)}
        aria-expanded={isOpen}
        aria-label={t("planning.leftovers.tooltip")}
        title={t("planning.leftovers.tooltip")}
      >
        <span aria-hidden="true">🧺</span>
        {lines.length > 0 && <span className="leftovers-basket__count">{lines.length}</span>}
      </button>

      {isOpen &&
        (isMobile ? (
          <BottomSheet onClose={() => setIsOpen(false)} title={t("planning.leftovers.title")}>
            {listContent}
          </BottomSheet>
        ) : (
          <div className="leftovers-basket__popover" ref={popoverRef}>
            <h2 className="leftovers-basket__heading">{t("planning.leftovers.title")}</h2>
            {listContent}
          </div>
        ))}
    </div>
  );
}

/**
 * One basket line, draggable (`@dnd-kit` `useDraggable`) onto a planning
 * cell to serve part of its pool there. The drag `data` carries what
 * `PlanningPage`'s `onDragEnd` needs to open the "how many portions?"
 * step; the sensors' activation distance (see `PlanningPage`) keeps a
 * plain click on "Jeter" from starting a drag.
 */
function LeftoverLineCard({
  item,
  available,
  isDiscarding,
  onDiscard,
}: {
  item: PlanningItemView;
  available: number;
  isDiscarding: boolean;
  onDiscard: () => void;
}) {
  const { t } = useTranslation();
  // The draggable node is the small grip button, not the whole `<li>`: a
  // pointer-based collision test then resolves cleanly to the single cell
  // under the cursor (a wide `<li>` box would straddle several cells).
  const { attributes, listeners, setNodeRef, isDragging } = useDraggable({
    id: dragIdForLeftover(item.id),
    data: { sourceItemId: item.id, recipeName: item.recipe.name, available },
  });

  return (
    <li className={isDragging ? "leftovers-basket__line is-dragging" : "leftovers-basket__line"}>
      <button
        type="button"
        ref={setNodeRef}
        className="leftovers-basket__drag-handle"
        aria-label={t("planning.leftovers.dragHandle", { recipe: item.recipe.name })}
        {...attributes}
        {...listeners}
      >
        ⠿
      </button>
      <div className="leftovers-basket__meta">
        <span className="leftovers-basket__recipe">{item.recipe.name}</span>
        <span className="leftovers-basket__origin">
          {t("planning.leftovers.origin", {
            day: t(`common.days.${item.weekDay}`),
            meal: t(`planning.meals.${item.meal}`),
          })}
        </span>
      </div>
      <span className="leftovers-basket__qty">
        {t("planning.leftovers.available", { count: available })}
      </span>
      <button
        type="button"
        className="leftovers-basket__discard"
        onClick={onDiscard}
        disabled={isDiscarding}
      >
        {t("planning.leftovers.discard")}
      </button>
    </li>
  );
}