import { useState } from "react";
import { useTranslation } from "react-i18next";
import { BookmarkPlus, GripVertical, Play, Star, Trash2 } from "lucide-react";
import {
  closestCenter,
  DndContext,
  PointerSensor,
  useSensor,
  useSensors,
  type DragEndEvent,
} from "@dnd-kit/core";
import {
  arrayMove,
  SortableContext,
  useSortable,
  verticalListSortingStrategy,
} from "@dnd-kit/sortable";
import { CSS } from "@dnd-kit/utilities";
import type { SavedView } from "../lib/api";
import Modal from "./Modal";
import { useSavedViews, asFilters } from "./SavedViewsProvider";
import { useActiveFilters } from "../lib/useActiveFilters";

// Master–detail manager for saved ("personal") views: the left column lists the views (drag to
// reorder) plus a "save the current filters" input; the right column shows the selected view's name,
// what filters it captures, its default flag, apply, and delete. Opened from the filter panel's title
// or the saved-views popover; all mutations flow through SavedViewsProvider.
function ViewRow({
  view,
  selected,
  active,
  onSelect,
}: {
  view: SavedView;
  selected: boolean;
  active: boolean;
  onSelect: () => void;
}) {
  const { t } = useTranslation();
  const { attributes, listeners, setNodeRef, transform, transition, isDragging } = useSortable({
    id: view.id,
  });
  return (
    <div
      ref={setNodeRef}
      style={{ transform: CSS.Transform.toString(transform), transition }}
      className={`flex items-center gap-1.5 rounded-lg pr-1.5 ${isDragging ? "opacity-60" : ""} ${
        selected ? "bg-accent/15" : "hover:bg-card"
      }`}
    >
      <button
        {...attributes}
        {...listeners}
        aria-label={t("views.reorder")}
        className="cursor-grab p-1.5 text-muted hover:text-fg"
      >
        <GripVertical className="h-3.5 w-3.5" />
      </button>
      <button
        onClick={onSelect}
        className={`flex-1 min-w-0 truncate py-1.5 text-left text-sm ${
          selected ? "text-accent" : "text-fg"
        }`}
      >
        {view.name}
      </button>
      {view.is_default && <Star className="h-3 w-3 shrink-0 fill-current text-accent" />}
      {active && <span className="mr-1 h-1.5 w-1.5 shrink-0 rounded-full bg-accent" />}
    </div>
  );
}

export default function PersonalViewsModal() {
  const { t } = useTranslation();
  const { views, activeViewId, apply, create, rename, toggleDefault, remove, reorder, closeModal } =
    useSavedViews();
  const sensors = useSensors(useSensor(PointerSensor, { activationConstraint: { distance: 4 } }));

  const [selectedId, setSelectedId] = useState<number | null>(activeViewId ?? views[0]?.id ?? null);
  const selected = views.find((v) => v.id === selectedId) ?? null;
  const [draftName, setDraftName] = useState("");

  // The selected view's captured filters, as the same human labels the toolbar chip row shows.
  const captured = useActiveFilters(
    selected ? asFilters(selected.filters) : ({ tags: [], channelIds: [] } as never),
    () => {},
  );

  async function onDragEnd(e: DragEndEvent) {
    const { active, over } = e;
    if (!over || active.id === over.id) return;
    const ids = views.map((v) => v.id);
    const next = arrayMove(ids, ids.indexOf(active.id as number), ids.indexOf(over.id as number));
    await reorder(next);
  }

  async function onCreate() {
    const name = draftName.trim();
    if (!name) return;
    if (await create(name)) setDraftName("");
  }

  return (
    <Modal title={t("views.manageTitle")} onClose={closeModal} maxWidth="max-w-2xl">
      <div className="grid min-h-[20rem] grid-cols-[minmax(0,14rem)_1fr] gap-4">
        {/* Left: the list + create */}
        <div className="flex flex-col border-r border-border/60 pr-4">
          <div className="flex-1 space-y-1 overflow-y-auto">
            {views.length === 0 && (
              <p className="px-1 py-2 text-2xs leading-snug text-muted">{t("views.empty")}</p>
            )}
            <DndContext sensors={sensors} collisionDetection={closestCenter} onDragEnd={onDragEnd}>
              <SortableContext
                items={views.map((v) => v.id)}
                strategy={verticalListSortingStrategy}
              >
                {views.map((v) => (
                  <ViewRow
                    key={v.id}
                    view={v}
                    selected={v.id === selectedId}
                    active={v.id === activeViewId}
                    onSelect={() => setSelectedId(v.id)}
                  />
                ))}
              </SortableContext>
            </DndContext>
          </div>
          <div className="mt-2 flex items-center gap-1.5 border-t border-border/60 pt-2">
            <input
              value={draftName}
              onChange={(e) => setDraftName(e.target.value)}
              onKeyDown={(e) => e.key === "Enter" && onCreate()}
              placeholder={t("views.namePlaceholder")}
              className="min-w-0 flex-1 rounded-lg border border-border bg-surface px-2 py-1.5 text-sm focus:border-accent focus:outline-hidden focus:ring-2 focus:ring-accent/30"
            />
            <button
              onClick={onCreate}
              disabled={!draftName.trim()}
              title={t("views.save")}
              className="inline-flex shrink-0 items-center gap-1 rounded-lg btn-primary px-2.5 py-1.5 text-sm font-semibold disabled:opacity-40"
            >
              <BookmarkPlus className="h-4 w-4" />
            </button>
          </div>
        </div>

        {/* Right: the selected view's detail */}
        {selected ? (
          <div className="flex flex-col gap-3">
            <input
              key={selected.id}
              defaultValue={selected.name}
              onBlur={(e) => {
                const next = e.target.value.trim();
                if (next && next !== selected.name) void rename(selected.id, next);
              }}
              className="rounded-lg border border-border bg-surface px-3 py-2 text-sm font-medium focus:border-accent focus:outline-hidden focus:ring-2 focus:ring-accent/30"
            />
            <div>
              <div className="mb-1.5 text-2xs font-semibold uppercase tracking-wider text-muted">
                {t("views.capturedFilters")}
              </div>
              {captured.length === 0 ? (
                <p className="text-xs text-muted">{t("views.capturedNone")}</p>
              ) : (
                <div className="flex flex-wrap gap-1.5">
                  {captured.map((f) => (
                    <span
                      key={f.key}
                      className="rounded-full bg-accent/10 px-2 py-0.5 text-2xs text-accent"
                    >
                      {f.label}
                    </span>
                  ))}
                </div>
              )}
            </div>
            <div className="mt-auto flex items-center gap-2 border-t border-border/60 pt-3">
              <button
                onClick={() => apply(selected)}
                className="inline-flex items-center gap-1.5 rounded-lg btn-primary px-3 py-1.5 text-sm font-semibold"
              >
                <Play className="h-3.5 w-3.5" />
                {t("views.apply")}
              </button>
              <button
                onClick={() => void toggleDefault(selected)}
                title={t("views.default")}
                className={`inline-flex items-center gap-1.5 rounded-lg border px-3 py-1.5 text-sm transition ${
                  selected.is_default
                    ? "border-accent text-accent"
                    : "border-border text-muted hover:text-fg"
                }`}
              >
                <Star className={`h-3.5 w-3.5 ${selected.is_default ? "fill-current" : ""}`} />
                {t("views.default")}
              </button>
              <button
                onClick={async () => {
                  const next = views.find((v) => v.id !== selected.id);
                  // Only move the selection if the delete actually happened (remove awaits a confirm
                  // and resolves false on cancel) — otherwise cancelling would still switch the pane.
                  if (await remove(selected)) setSelectedId(next?.id ?? null);
                }}
                title={t("views.delete")}
                className="ml-auto inline-flex items-center gap-1.5 rounded-lg border border-border px-3 py-1.5 text-sm text-danger transition hover:border-danger"
              >
                <Trash2 className="h-3.5 w-3.5" />
                {t("views.delete")}
              </button>
            </div>
          </div>
        ) : (
          <div className="flex items-center justify-center text-sm text-muted">
            {t("views.selectPrompt")}
          </div>
        )}
      </div>
    </Modal>
  );
}