import { useState } from "react";
import type { WidgetProps } from "./types";
import { ReservedControls } from "./ReservedControls";

export function MultiselectWidget({ descriptor, onRespond }: WidgetProps) {
  const options = descriptor.options ?? [];
  const initialChecked = new Set(options.filter((o) => o.selected).map((o) => o.id));
  const [checked, setChecked] = useState<Set<string>>(initialChecked);

  const allChecked = options.length > 0 && options.every((o) => checked.has(o.id));

  function toggle(id: string) {
    setChecked((prev) => {
      const next = new Set(prev);
      if (next.has(id)) next.delete(id);
      else next.add(id);
      return next;
    });
  }

  const isDisabled = descriptor.allow_empty === false && checked.size === 0;

  return (
    <div className="space-y-4 rounded-xl border border-border/70 bg-card p-4 shadow-sm">
      {descriptor.title && (
        <p className="text-[0.95rem] font-semibold leading-snug text-foreground">
          {descriptor.title}
        </p>
      )}
      <div className="flex flex-col">
        {/* Prominent select-all control at the head of the list. */}
        <div className="flex items-center justify-between border-b border-border/60 pb-2">
          <button
            className="text-sm font-semibold text-primary transition-colors hover:text-[oklch(var(--primary-hover))]"
            onClick={() =>
              setChecked(allChecked ? new Set() : new Set(options.map((o) => o.id)))
            }
          >
            {allChecked ? "Deselect all" : "Select all"}
          </button>
          <span className="text-xs tabular-nums text-muted-foreground">
            {checked.size} / {options.length} {descriptor.selection_label ?? "selected"}
          </span>
        </div>
        <div className="flex flex-col gap-1 pt-2">
          {options.map((o) => (
            <label
              key={o.id}
              className={`flex cursor-pointer items-center gap-2.5 rounded-lg border px-2.5 py-2 text-sm text-foreground transition-colors hover:bg-accent ${
                checked.has(o.id) ? "border-border/60 bg-accent/60" : "border-transparent"
              }`}
            >
              <input
                type="checkbox"
                className="size-4 shrink-0 accent-[oklch(var(--primary))]"
                checked={checked.has(o.id)}
                onChange={() => toggle(o.id)}
              />
              <span>{o.label}</span>
            </label>
          ))}
        </div>
      </div>
      <div>
        <button
          className="rounded-md bg-primary px-4 py-2 text-sm font-semibold text-primary-foreground shadow-xs transition-colors hover:bg-[oklch(var(--primary-hover))] disabled:cursor-not-allowed disabled:opacity-50"
          disabled={isDisabled}
          onClick={() => onRespond({ id: descriptor.id, kind: "multiselect", choices: Array.from(checked) })}
        >
          {descriptor.confirm_label ?? "Confirm"}
        </button>
      </div>
      <ReservedControls
        reserved={descriptor.reserved}
        onControl={(c, t) => onRespond({ id: descriptor.id, control: c, ...(t !== undefined ? { text: t } : {}) })}
      />
    </div>
  );
}