import { type ReactNode } from "react";
import { useTranslation } from "react-i18next";
import { Check, Pencil, Pin, PinOff, RotateCcw } from "lucide-react";
import { useScrollFade } from "../lib/useScrollFade";
import { useHoverFocusWithin } from "../lib/useHoverFocusWithin";

// The shared floating side panel — one shell for the Feed / Plex / Playlists rails so they read as
// one system, and the same peek-open model as the nav rail: unpinned it sits as a small tab docked
// against the rail's right edge (this panel is the flex sibling right after it) and expands into a
// rounded glass card on hover/focus WITHOUT pushing content; pinned it stays expanded in-flow.
// `collapsed` (persisted per-account) therefore means "unpinned".
export default function SidePanel({
  title,
  icon,
  count = 0,
  collapsed,
  onToggleCollapse,
  editing = false,
  onToggleEditing,
  onReset,
  editHint,
  actions,
  children,
}: {
  title: string;
  icon: ReactNode;
  count?: number;
  collapsed: boolean;
  onToggleCollapse: () => void;
  // Customize (reorder/hide) mode — omit onToggleEditing to hide the pencil entirely.
  editing?: boolean;
  onToggleEditing?: () => void;
  onReset?: () => void;
  editHint?: string;
  // Extra header controls shown when NOT editing (e.g. the feed's Clear all + Share view).
  actions?: ReactNode;
  children: ReactNode;
}) {
  const { t } = useTranslation();
  const fade = useScrollFade();
  const peek = useHoverFocusWithin();
  const pinned = !collapsed;
  const expanded = pinned || peek.active;

  return (
    // Layout slot: reserves only the tab's gutter when unpinned, so the expanded card overlays
    // content instead of pushing it. Pinned reserves the full width (in-flow), as before.
    <div
      {...peek.handlers}
      className={`hidden md:block relative shrink-0 transition-[width] ${pinned ? "w-67" : "w-9"}`}
    >
      {/* The tab: a small handle flush against the nav rail, flat on the docked edge. It stays
          mounted while the card is open — swapping it out from under the pointer would drop the very
          hover that opened the card, and unmounting it while focused would throw keyboard focus to
          nowhere. It only goes transparent: the card's rounded corner cuts away its own pixels, and
          this square-cornered tab sits right under that arc, so it would otherwise bleed through.
          `opacity-0` (not `invisible`/`hidden`) keeps it hoverable and focusable. */}
      <button
        onClick={onToggleCollapse}
        aria-label={pinned ? t("sidebar.unpin") : t("sidebar.pin")}
        className={`glass glass-hover absolute top-3 left-0 z-paneltab flex flex-col items-center gap-2 px-1.5 py-3 rounded-l-none rounded-r-xl transition-opacity ${
          expanded ? "opacity-0" : ""
        } ${count > 0 ? "ring-1 ring-accent/40" : ""}`}
      >
        <span className="text-accent">{icon}</span>
        {count > 0 && (
          <span className="bg-accent text-accent-fg text-3xs font-bold px-1.5 py-0.5 rounded-full tabular-nums">
            {count > 9 ? "9+" : count}
          </span>
        )}
        <span
          className="text-2xs font-semibold uppercase tracking-[0.18em] text-muted"
          style={{ writingMode: "vertical-rl", transform: "rotate(180deg)" }}
        >
          {title}
        </span>
      </button>

      {expanded && (
        <aside className="glass absolute top-3 bottom-3 left-0 z-panel w-64 rounded-2xl flex flex-col overflow-hidden">
          {/* Row 1 — identity only: pin, icon, title (flexes + truncates last), count, customize.
              Module actions live on their own row below so the title always has room. */}
          <div className="flex items-center gap-1.5 px-3 py-2.5 border-b border-border/60 flex-none">
            <button
              onClick={onToggleCollapse}
              title={pinned ? t("sidebar.unpin") : t("sidebar.pin")}
              aria-label={pinned ? t("sidebar.unpin") : t("sidebar.pin")}
              className="shrink-0 -ml-1 p-1 rounded-md text-muted hover:text-fg hover:bg-card transition"
            >
              {pinned ? <PinOff className="w-4 h-4" /> : <Pin className="w-4 h-4" />}
            </button>
            <span className="shrink-0 flex text-accent">{icon}</span>
            <span className="flex-1 min-w-0 truncate text-xs font-bold uppercase tracking-[0.12em]">
              {title}
            </span>
            {count > 0 && (
              <span
                title={t("sidebar.activeCount", { count })}
                className="shrink-0 min-w-4.5 h-4.5 px-1.5 rounded-full bg-accent/15 text-accent text-2xs font-semibold inline-flex items-center justify-center tabular-nums"
              >
                {count}
              </span>
            )}
            {editing && onReset && (
              <button
                onClick={onReset}
                title={t("sidebar.resetDefaults")}
                className="shrink-0 p-1.5 rounded-lg text-muted hover:text-fg hover:bg-card transition"
              >
                <RotateCcw className="w-4 h-4" />
              </button>
            )}
            {onToggleEditing && (
              <button
                onClick={onToggleEditing}
                title={editing ? t("sidebar.done") : t("sidebar.customize")}
                className={`shrink-0 p-1.5 rounded-lg transition hover:bg-card ${
                  editing ? "text-accent" : "text-muted hover:text-fg"
                }`}
              >
                {editing ? <Check className="w-4 h-4" /> : <Pencil className="w-4 h-4" />}
              </button>
            )}
          </div>

          {/* Row 2 — module actions (e.g. Clear all / Share), only when not customizing. */}
          {!editing && actions && (
            <div className="flex items-center justify-between gap-2 px-3 py-1.5 border-b border-border/60 flex-none">
              {actions}
            </div>
          )}

          <div
            ref={fade.ref}
            style={fade.style}
            className="flex-1 min-h-0 overflow-y-auto no-scrollbar"
          >
            <div className="p-3 space-y-3">
              {editing && editHint && <div className="text-2xs text-muted">{editHint}</div>}
              {children}
            </div>
          </div>
        </aside>
      )}
    </div>
  );
}