Describe Filters

"use client";

import * as React from "react";
import { AnimatePresence, motion } from "motion/react";
import { ArrowUp, ListFilter, Search, Sparkles, X } from "lucide-react";

import { cn } from "@/lib/utils";

export interface DescribeFiltersColumn<Row> {
  key: string;
  label: string;
  /** Renders the cell; defaults to `String(row[key])`. */
  render?: (row: Row) => React.ReactNode;
  className?: string;
}

export interface DescribedFilter<Row> {
  id: string;
  /** Column label, or a concept label like "About" when no column covers the request. */
  field: string;
  operator: string;
  value: string;
  /**
   * `column` filters map onto a real column. `semantic` filters have no
   * column behind them — the model matched rows by meaning — so the chip is
   * marked differently and the user knows it can't be edited like a column.
   */
  kind: "column" | "semantic";
  test: (row: Row) => boolean;
}

export interface DescribeResult<Row> {
  filters: DescribedFilter<Row>[];
}

export interface DescribeFiltersTableProps<Row extends { id: string }> {
  columns: DescribeFiltersColumn<Row>[];
  rows: Row[];
  /** Turns a plain-language description into filters. */
  onDescribe: (description: string) => Promise<DescribeResult<Row>>;
  /** Used by the plain keyword search box. */
  searchText?: (row: Row) => string;
  /** Example descriptions shown while the describe field is empty. */
  suggestions?: string[];
  initialFilters?: DescribedFilter<Row>[];
  describePlaceholder?: string;
  className?: string;
}

export function DescribeFiltersTable<Row extends { id: string }>({
  columns,
  rows,
  onDescribe,
  searchText,
  suggestions = [],
  initialFilters = [],
  describePlaceholder = "Describe the rows you want to see…",
  className,
}: DescribeFiltersTableProps<Row>) {
  const [mode, setMode] = React.useState<"idle" | "describing" | "pending">("idle");
  const [draft, setDraft] = React.useState("");
  const [lastDescription, setLastDescription] = React.useState<string | null>(null);
  const [filters, setFilters] = React.useState(initialFilters);
  /** Ids of filters produced by the last description — they get the AI marker. */
  const [generatedIds, setGeneratedIds] = React.useState<Set<string>>(new Set());
  const [query, setQuery] = React.useState("");
  const [error, setError] = React.useState<string | null>(null);

  const describeRef = React.useRef<HTMLInputElement>(null);
  const describeButtonRef = React.useRef<HTMLButtonElement>(null);
  const restoreFocus = React.useRef(false);

  React.useEffect(() => {
    if (mode === "describing") describeRef.current?.focus();
    if (mode === "idle" && restoreFocus.current) {
      restoreFocus.current = false;
      describeButtonRef.current?.focus();
    }
  }, [mode]);

  const visibleRows = React.useMemo(() => {
    const q = query.trim().toLowerCase();
    return rows.filter(
      (row) =>
        filters.every((f) => f.test(row)) && (!q || (searchText?.(row) ?? "").toLowerCase().includes(q))
    );
  }, [rows, filters, query, searchText]);

  function openDescribe(prefill = "") {
    setDraft(prefill);
    setError(null);
    setMode("describing");
  }

  function cancelDescribe() {
    restoreFocus.current = true;
    setMode("idle");
  }

  async function submit(description: string) {
    const trimmed = description.trim();
    if (!trimmed || mode === "pending") return;
    setDraft(trimmed);
    setMode("pending");
    setError(null);
    try {
      const result = await onDescribe(trimmed);
      // A description replaces the previous generated set but keeps filters
      // the user added by hand.
      setFilters((prev) => [...prev.filter((f) => !generatedIds.has(f.id)), ...result.filters]);
      setGeneratedIds(new Set(result.filters.map((f) => f.id)));
      setLastDescription(trimmed);
      restoreFocus.current = true;
      setMode("idle");
    } catch {
      setError("Couldn't turn that into filters. Try rephrasing.");
      setMode("describing");
    }
  }

  function removeFilter(id: string) {
    setFilters((prev) => prev.filter((f) => f.id !== id));
    setGeneratedIds((prev) => {
      const next = new Set(prev);
      next.delete(id);
      if (next.size === 0) setLastDescription(null);
      return next;
    });
  }

  function clearAll() {
    setFilters([]);
    setGeneratedIds(new Set());
    setLastDescription(null);
  }

  const busy = mode === "pending";
  const showSuggestions = mode === "describing" && !draft && suggestions.length > 0;

  return (
    <div className={cn("w-full overflow-hidden rounded-2xl border bg-card text-sm shadow-sm", className)}>
      {/* Toolbar */}
      <div className="border-b">
        <div className="flex min-h-14 items-center gap-2 px-3 py-2.5">
          <AnimatePresence mode="popLayout" initial={false}>
            {mode === "idle" ? (
              <motion.div
                key="toolbar"
                initial={{ opacity: 0, y: 4 }}
                animate={{ opacity: 1, y: 0 }}
                exit={{ opacity: 0, y: -4 }}
                transition={{ duration: 0.15 }}
                className="flex min-w-0 flex-1 flex-wrap items-center gap-2"
              >
                <button
                  ref={describeButtonRef}
                  type="button"
                  onClick={() => openDescribe()}
                  className="flex h-8 shrink-0 items-center gap-1.5 rounded-full border bg-background px-3 font-medium transition-colors hover:bg-accent"
                >
                  <Sparkles className="size-3.5" aria-hidden />
                  Describe
                </button>

                <label className="flex h-8 w-40 shrink-0 items-center gap-2 rounded-full border bg-background px-3 text-muted-foreground focus-within:ring-2 focus-within:ring-ring/40">
                  <Search className="size-3.5 shrink-0" aria-hidden />
                  <input
                    value={query}
                    onChange={(e) => setQuery(e.target.value)}
                    placeholder="Search"
                    aria-label="Search rows"
                    className="min-w-0 flex-1 bg-transparent text-foreground outline-none placeholder:text-muted-foreground"
                  />
                </label>

                {filters.length > 0 && (
                  <span className="flex size-8 shrink-0 items-center justify-center text-muted-foreground" aria-hidden>
                    <ListFilter className="size-4" />
                  </span>
                )}

                <ul className="contents" aria-label="Active filters">
                  <AnimatePresence initial={false}>
                    {filters.map((f, i) => (
                      <FilterChip
                        key={f.id}
                        filter={f}
                        generated={generatedIds.has(f.id)}
                        delay={generatedIds.has(f.id) ? i * 0.06 : 0}
                        onRemove={() => removeFilter(f.id)}
                      />
                    ))}
                  </AnimatePresence>
                </ul>

                {filters.length > 1 && (
                  <button
                    type="button"
                    onClick={clearAll}
                    className="h-8 shrink-0 rounded-full px-2 text-xs text-muted-foreground transition-colors hover:text-foreground"
                  >
                    Clear all
                  </button>
                )}
              </motion.div>
            ) : (
              <motion.form
                key="describe"
                initial={{ opacity: 0, y: 4 }}
                animate={{ opacity: 1, y: 0 }}
                exit={{ opacity: 0, y: -4 }}
                transition={{ duration: 0.15 }}
                onSubmit={(e) => {
                  e.preventDefault();
                  submit(draft);
                }}
                onKeyDown={(e) => {
                  if (e.key === "Escape" && !busy) {
                    e.preventDefault();
                    cancelDescribe();
                  }
                }}
                className="flex min-w-0 flex-1 items-center gap-2"
              >
                <button
                  type="button"
                  onClick={cancelDescribe}
                  disabled={busy}
                  aria-label="Cancel describing"
                  className="flex size-8 shrink-0 items-center justify-center rounded-full text-muted-foreground transition-colors hover:bg-accent hover:text-foreground disabled:opacity-40"
                >
                  <X className="size-4" />
                </button>
                <div className="relative min-w-0 flex-1">
                  <input
                    ref={describeRef}
                    value={draft}
                    onChange={(e) => {
                      setDraft(e.target.value);
                      setError(null);
                    }}
                    readOnly={busy}
                    placeholder={describePlaceholder}
                    aria-label="Describe filters"
                    aria-describedby={error ? "describe-filters-error" : undefined}
                    className={cn(
                      "h-8 w-full bg-transparent outline-none placeholder:text-muted-foreground",
                      busy && "text-muted-foreground"
                    )}
                  />
                </div>
                {busy ? (
                  <span className="flex shrink-0 items-center gap-1.5 pr-1 text-xs text-muted-foreground" role="status">
                    <Sparkles className="size-3.5 animate-spin [animation-duration:2s]" aria-hidden />
                    <span className="animate-pulse">Building filters</span>
                  </span>
                ) : (
                  <button
                    type="submit"
                    disabled={!draft.trim()}
                    aria-label="Apply description"
                    className="flex size-8 shrink-0 items-center justify-center rounded-full bg-primary text-primary-foreground transition-opacity disabled:opacity-30"
                  >
                    <ArrowUp className="size-4" />
                  </button>
                )}
              </motion.form>
            )}
          </AnimatePresence>
        </div>

        {/* Suggestions & errors expand inline under the field and push the
            table down — an overlay would cover the header and spill out of
            the card when the table is short. */}
        <AnimatePresence initial={false}>
          {(showSuggestions || error) && (
            <motion.div
              initial={{ height: 0, opacity: 0 }}
              animate={{ height: "auto", opacity: 1 }}
              exit={{ height: 0, opacity: 0 }}
              transition={{ duration: 0.18 }}
              className="overflow-hidden"
            >
              {error ? (
                <p id="describe-filters-error" role="alert" className="px-4 pb-3 text-xs text-destructive">
                  {error}
                </p>
              ) : (
                <div className="px-2 pb-2">
                  <p className="px-3 pb-1 text-xs text-muted-foreground">Try</p>
                  {suggestions.map((s) => (
                    <button
                      key={s}
                      type="button"
                      onClick={() => submit(s)}
                      className="flex w-full items-center gap-2 rounded-lg px-3 py-2 text-left transition-colors hover:bg-accent"
                    >
                      <Sparkles className="size-3.5 shrink-0 text-muted-foreground" aria-hidden />
                      {s}
                    </button>
                  ))}
                </div>
              )}
            </motion.div>
          )}
        </AnimatePresence>
      </div>

      {/* Interpretation line: what was asked, and how to revise it. */}
      <AnimatePresence initial={false}>
        {lastDescription && mode === "idle" && (
          <motion.div
            initial={{ height: 0, opacity: 0 }}
            animate={{ height: "auto", opacity: 1 }}
            exit={{ height: 0, opacity: 0 }}
            transition={{ duration: 0.18 }}
            className="overflow-hidden border-b bg-muted/40"
          >
            <p className="flex items-center gap-1.5 px-4 py-2 text-xs text-muted-foreground" aria-live="polite">
              <Sparkles className="size-3 shrink-0" aria-hidden />
              <span className="min-w-0 truncate">
                Filtered for <span className="text-foreground">“{lastDescription}”</span> · {visibleRows.length} of{" "}
                {rows.length}
              </span>
              <button
                type="button"
                onClick={() => openDescribe(lastDescription)}
                className="ml-auto shrink-0 font-medium text-foreground underline-offset-2 hover:underline"
              >
                Edit
              </button>
            </p>
          </motion.div>
        )}
      </AnimatePresence>

      {/* Table */}
      <div className="max-h-80 overflow-auto">
        <table className="w-full border-collapse" aria-busy={busy}>
          <thead className="sticky top-0 z-[1] bg-card">
            <tr className="border-b text-left text-xs text-muted-foreground">
              {columns.map((c) => (
                <th key={c.key} scope="col" className={cn("px-4 py-2.5 font-medium", c.className)}>
                  {c.label}
                </th>
              ))}
            </tr>
          </thead>
          <motion.tbody animate={{ opacity: busy ? 0.4 : 1 }} transition={{ duration: 0.2 }}>
            <AnimatePresence initial={false}>
              {visibleRows.map((row) => (
                <motion.tr
                  key={row.id}
                  layout="position"
                  initial={{ opacity: 0 }}
                  animate={{ opacity: 1 }}
                  exit={{ opacity: 0 }}
                  transition={{ duration: 0.18 }}
                  className="border-b last:border-b-0"
                >
                  {columns.map((c) => (
                    <td key={c.key} className={cn("px-4 py-2.5", c.className)}>
                      {c.render ? c.render(row) : String((row as Record<string, unknown>)[c.key] ?? "")}
                    </td>
                  ))}
                </motion.tr>
              ))}
            </AnimatePresence>
          </motion.tbody>
        </table>
        {visibleRows.length === 0 && (
          <div className="flex flex-col items-center gap-2 px-4 py-10 text-center">
            <p className="text-muted-foreground">No rows match these filters.</p>
            {lastDescription && (
              <button
                type="button"
                onClick={() => openDescribe(lastDescription)}
                className="text-xs font-medium underline-offset-2 hover:underline"
              >
                Edit description
              </button>
            )}
          </div>
        )}
      </div>
    </div>
  );
}

function FilterChip<Row>({
  filter,
  generated,
  delay,
  onRemove,
}: {
  filter: DescribedFilter<Row>;
  generated: boolean;
  delay: number;
  onRemove: () => void;
}) {
  const semantic = filter.kind === "semantic";
  const label = `${filter.field} ${filter.operator} ${filter.value}`;
  return (
    <motion.li
      layout
      initial={{ opacity: 0, scale: 0.92 }}
      animate={{ opacity: 1, scale: 1, transition: { delay, duration: 0.18 } }}
      exit={{ opacity: 0, scale: 0.92, transition: { duration: 0.12 } }}
      title={semantic ? "No column covers this — rows were matched by meaning" : undefined}
      className={cn(
        "flex h-8 shrink-0 items-center gap-1.5 rounded-full border bg-background pl-3 pr-1",
        semantic && "border-dashed"
      )}
    >
      {generated && <Sparkles className="size-3 shrink-0 text-muted-foreground" aria-label="Generated" />}
      <span className={cn(semantic && "italic")}>{filter.field}</span>
      <span className="text-muted-foreground">· {filter.operator} ·</span>
      <span className="max-w-48 truncate">{filter.value}</span>
      <button
        type="button"
        onClick={onRemove}
        aria-label={`Remove filter: ${label}`}
        className="flex size-6 items-center justify-center rounded-full text-muted-foreground transition-colors hover:bg-accent hover:text-foreground"
      >
        <X className="size-3.5" />
      </button>
    </motion.li>
  );
}