import { useRef, useState, type ReactNode } from "react";
import { useTranslation } from "react-i18next";
import { ArrowDown, ArrowUp, ListFilter, X } from "lucide-react";
import { PopoverItem, PopoverSurface, useAnchoredPopover } from "./AnchoredPopover";
import { useScrollFade } from "../lib/useScrollFade";
import { type SortState } from "../lib/columnSort";

// The column-header machinery — the column contract, the sortable header row with its filter
// funnel + popover, and the filter predicate — lifted OUT of DataTable so a non-DataTable body can
// render under the same headers.
//
// Why it lives here and not in DataTable: DataTable owns its filter/sort/page state internally,
// while the playlist manager's body is a drag-reorderable list whose order is the persisted
// server-side one. Two owners of the same ordering fight; composing these pieces instead lets the
// playlist keep its stored order and still get real column headers. Same move as E4 S3's
// ChannelLayoutGrid, which builds a card view straight from the `Column<T>` render closures.

type ColumnFilter<T> =
  | { kind: "text"; get: (row: T) => string }
  | {
      kind: "select";
      options: { value: string; label: string }[];
      test: (row: T, value: string) => boolean;
    }
  | {
      kind: "multi";
      options: { value: string; label: string }[];
      test: (row: T, values: string[]) => boolean;
    };

export interface Column<T> {
  key: string;
  header: string;
  render: (row: T) => ReactNode;
  align?: "left" | "right" | "center";
  width?: string;
  sortable?: boolean;
  sortValue?: (row: T) => string | number;
  filter?: ColumnFilter<T>;
  // Keep the cell on one line so the column auto-sizes to its content (table-layout: auto).
  nowrap?: boolean;
  // Card fallback (below md): `cardPrimary` renders as the card heading (no label); `hideInCard`
  // omits the column; `cardLabel:false` shows the value without its header label.
  cardPrimary?: boolean;
  hideInCard?: boolean;
  cardLabel?: boolean;
}

export type FilterMap = Record<string, string | string[]>;

export function isActive(value: string | string[] | undefined): boolean {
  return Array.isArray(value) ? value.length > 0 : !!value;
}

/** Apply every column's own filter predicate. A column with no filter, or an empty value, passes. */
export function filterRows<T>(rows: T[], columns: Column<T>[], filters: FilterMap): T[] {
  return rows.filter((row) =>
    columns.every((col) => {
      const f = col.filter;
      if (!f) return true;
      const val = filters[col.key];
      if (!isActive(val)) return true;
      if (f.kind === "text") return f.get(row).toLowerCase().includes(String(val).toLowerCase());
      if (f.kind === "select") return f.test(row, String(val));
      return f.test(row, val as string[]);
    }),
  );
}

export const alignClass = (a?: "left" | "right" | "center") =>
  a === "right" ? "text-right" : a === "center" ? "text-center" : "text-left";

// The multi-select filter's option list, capped and scrollable. Its own component because it owns a
// hook — see the FilterPopover note below for why nesting either of these would remount them.
function FilterOptionList({ children }: { children: ReactNode }) {
  const fade = useScrollFade();
  return (
    <div
      ref={fade.ref}
      style={fade.style}
      className="flex flex-col gap-0.5 max-h-60 overflow-y-auto no-scrollbar"
    >
      {children}
    </div>
  );
}

// MODULE LEVEL, deliberately. The panel used to be declared inside DataTable's body, which made it a
// NEW component type on every render: React unmounted and remounted the popover on each keystroke,
// so the caret jumped to the end and IME composition (accents, any CJK input) broke mid-word. The
// `autoFocus` masked it well enough that it read as "the filter is just twitchy".
//
// The funnel and its panel live in ONE component because the R8 popover platform anchors the panel
// to its trigger. That also retires this file's three hand-rolled focus chores: capturing the
// trigger element at open time (a `ref` scoped to the open column nulled out before focus could go
// back), the restore-focus effect that stopped Escape stranding focus on <body>, and the useDismiss
// registration that had to include the trigger so its own mousedown didn't close-then-reopen.
function FilterFunnel<T>({
  col,
  value,
  onApply,
  open,
  onOpenChange,
}: {
  col: Column<T>;
  value: string | string[] | undefined;
  onApply: (key: string, value: string | string[]) => void;
  open: boolean;
  onOpenChange: (open: boolean) => void;
}) {
  const { t } = useTranslation();
  const f = col.filter!;
  const inputRef = useRef<HTMLInputElement | null>(null);
  // A text filter is a free-text field, so it is a dialog whose input takes focus; the option lists
  // are real menus with roving focus. `select` is one exclusive choice (radio), `multi` is several
  // independent ones (checkbox).
  const isText = f.kind === "text";
  const pop = useAnchoredPopover({
    open,
    onOpenChange,
    mode: isText ? "dialog" : "menu",
    role: isText ? "dialog" : "menu",
  });
  const filterOn = isActive(value);

  return (
    <>
      <button
        ref={pop.refs.setReference}
        {...pop.getReferenceProps()}
        aria-label={t("datatable.filter")}
        // Generous padding: the icon alone was a 14x14 hit target, the smallest in the app.
        className={`-m-1.5 p-1.5 transition ${
          filterOn ? "text-accent" : "text-muted/60 hover:text-fg"
        }`}
      >
        <ListFilter className="w-3.5 h-3.5" />
      </button>
      <PopoverSurface
        popover={pop}
        ariaLabel={col.header}
        initialFocus={isText ? inputRef : undefined}
        className="glass-menu w-52 rounded-xl p-2 animate-[popIn_0.16s_ease]"
      >
        {f.kind === "text" && (
          <input
            ref={inputRef}
            value={(value as string) ?? ""}
            onChange={(e) => onApply(col.key, e.target.value)}
            placeholder={col.header}
            className="w-full bg-card border border-border rounded-md px-2 py-1 text-xs outline-none focus:border-accent"
          />
        )}
        {f.kind === "select" && (
          <div className="flex flex-col gap-0.5">
            <PopoverItem
              role="menuitemradio"
              checked={!filterOn}
              onSelect={() => onApply(col.key, "")}
              label={t("datatable.all")}
              className={`text-left text-xs px-2 py-1.5 rounded-md outline-none transition data-[active]:ring-1 data-[active]:ring-accent ${
                !filterOn ? "bg-accent text-accent-fg" : "text-muted hover:bg-card"
              }`}
            >
              {t("datatable.all")}
            </PopoverItem>
            {f.options.map((o) => (
              <PopoverItem
                key={o.value}
                role="menuitemradio"
                checked={value === o.value}
                onSelect={() => onApply(col.key, o.value)}
                label={o.label}
                className={`text-left text-xs px-2 py-1.5 rounded-md outline-none transition data-[active]:ring-1 data-[active]:ring-accent ${
                  value === o.value ? "bg-accent text-accent-fg" : "text-muted hover:bg-card"
                }`}
              >
                {o.label}
              </PopoverItem>
            ))}
          </div>
        )}
        {f.kind === "multi" && (
          <FilterOptionList>
            {f.options.length === 0 && (
              <span className="text-xs text-muted px-2 py-1">{t("datatable.noOptions")}</span>
            )}
            {f.options.map((o) => {
              const arr = (value as string[]) ?? [];
              const on = arr.includes(o.value);
              return (
                <PopoverItem
                  key={o.value}
                  role="menuitemcheckbox"
                  checked={on}
                  onSelect={() =>
                    onApply(col.key, on ? arr.filter((x) => x !== o.value) : [...arr, o.value])
                  }
                  label={o.label}
                  className={`flex w-full items-center gap-2 text-left text-xs px-2 py-1.5 rounded-md outline-none transition data-[active]:bg-[color-mix(in_srgb,var(--accent)_24%,transparent)] ${
                    on ? "text-fg" : "text-muted hover:bg-card"
                  }`}
                >
                  <span
                    className={`w-3.5 h-3.5 rounded border flex items-center justify-center ${
                      on ? "bg-accent border-accent text-accent-fg" : "border-border"
                    }`}
                  >
                    {on && <X className="w-2.5 h-2.5" />}
                  </span>
                  {o.label}
                </PopoverItem>
              );
            })}
          </FilterOptionList>
        )}
        {filterOn && (
          <button
            onClick={() => onApply(col.key, f.kind === "multi" ? [] : "")}
            className="mt-1.5 w-full text-xs text-muted hover:text-accent transition"
          >
            {t("datatable.clear")}
          </button>
        )}
      </PopoverSurface>
    </>
  );
}

/** The sticky `<thead>`: one sortable/filterable cell per column.
 *
 * Sticky-header notes (kept from DataTable, where this look was designed): the header stays put at
 * the top of the page scroller while rows scroll under it. `bg-bg` on each cell stops rows showing
 * through; the bottom border rides a `box-shadow` because a sticky `<tr>`'s own border scrolls away
 * with the collapsed table box in some browsers. The `::after` paints a short fade just BELOW the
 * header so rows dissolve as they slide under it while the header itself stays crisp — which is why
 * pages using this pass `PageShell fadeTop={false}`. */
export function ColumnHead<T>({
  columns,
  sort,
  onToggleSort,
  filters,
  onFilter,
}: {
  columns: Column<T>[];
  sort: SortState;
  onToggleSort: (key: string) => void;
  filters: FilterMap;
  onFilter: (key: string, value: string | string[]) => void;
}) {
  // Only one column's filter panel is open at a time; each funnel owns its own anchoring.
  const [openFilter, setOpenFilter] = useState<string | null>(null);

  return (
    <thead className="sticky top-0 z-base after:pointer-events-none after:absolute after:inset-x-0 after:top-full after:h-4 after:bg-[linear-gradient(to_bottom,var(--bg),transparent)] after:content-['']">
      <tr className="text-muted [&>th]:shadow-[inset_0_-1px_0_var(--border)]">
        {columns.map((col) => {
          const isSorted = sort?.key === col.key;
          return (
            <th
              key={col.key}
              style={col.width ? { width: col.width } : undefined}
              className={`relative font-medium px-2 py-2 whitespace-nowrap bg-bg ${alignClass(col.align)}`}
              aria-sort={
                col.sortable
                  ? isSorted
                    ? sort!.dir === "asc"
                      ? "ascending"
                      : "descending"
                    : "none"
                  : undefined
              }
            >
              <span className="inline-flex items-center gap-1">
                {/* Only a sortable header is a control. A non-sortable one used to render a
                    focusable no-op button, which put unlabeled dead stops in the tab order —
                    two of them per playlist table, whose grip and actions headers are empty. */}
                {col.sortable ? (
                  <button
                    onClick={() => onToggleSort(col.key)}
                    className="inline-flex items-center gap-1 hover:text-fg cursor-pointer"
                  >
                    {col.header}
                    {isSorted &&
                      sort &&
                      (sort.dir === "asc" ? (
                        <ArrowUp className="w-3 h-3" />
                      ) : (
                        <ArrowDown className="w-3 h-3" />
                      ))}
                  </button>
                ) : (
                  <span>{col.header}</span>
                )}
                {col.filter && (
                  <FilterFunnel
                    col={col}
                    value={filters[col.key]}
                    onApply={onFilter}
                    open={openFilter === col.key}
                    onOpenChange={(o) => setOpenFilter(o ? col.key : null)}
                  />
                )}
              </span>
            </th>
          );
        })}
      </tr>
    </thead>
  );
}
