'use client';

import Link from 'next/link';
import { ChevronRight } from 'lucide-react';
import { cn } from '@/lib/utils';

/**
 * A titled group of rows. Settings is a list of lists.
 *
 * The gap below is 32px rather than 24px because these are the "blocks within a
 * screen" of §4, not siblings in a list — at 24px the group titles stopped
 * reading as titles and the page became one undifferentiated stack of boxes.
 */
export function SettingsGroup({
  title,
  note,
  children,
}: {
  title: string;
  note?: string;
  children: React.ReactNode;
}) {
  return (
    <section className="mb-8">
      <h2 className="mb-2 px-1 text-overline uppercase text-faint">{title}</h2>
      <div className="divide-y divide-hairline overflow-hidden rounded-card border border-hairline bg-raised">
        {children}
      </div>
      {note && <p className="mt-2 px-1 text-meta text-muted">{note}</p>}
    </section>
  );
}

/** Shared by every row shape below, so a group never looks stitched together. */
const rowClasses = 'flex w-full items-center gap-3 px-4 py-3.5 text-left';
const interactiveClasses = 'transition-colors duration-[120ms] ease-standard hover:bg-sunken';

/**
 * A read-only, navigational, or linking row.
 *
 * `href` and `onClick` are alternatives, and one of them must be present for the
 * row to draw a chevron. A row that shows the chevron and does nothing is the
 * worst state available here — it is indistinguishable from a broken link, so
 * the affordance is tied to the destination rather than set by hand.
 */
export function SettingsRow({
  label,
  value,
  hint,
  href,
  onClick,
  danger,
  disabled,
}: {
  label: string;
  value?: React.ReactNode;
  hint?: string;
  href?: string;
  onClick?: () => void;
  danger?: boolean;
  disabled?: boolean;
}) {
  const interactive = Boolean(href ?? onClick) && !disabled;

  const inner = (
    <>
      <span className="min-w-0 flex-1">
        <span className={cn('block text-body-sm', danger ? 'text-danger' : 'text-strong')}>
          {label}
        </span>
        {hint && <span className="mt-0.5 block text-meta text-muted">{hint}</span>}
      </span>
      {value !== undefined && (
        // Shrinkable and truncating, NOT shrink-0: an email long enough to need
        // the room used to take it from the label, which collapsed to nothing
        // while the value it was labelling ran on past the bezel.
        <span className="min-w-0 truncate text-right text-body-sm text-muted">{value}</span>
      )}
      {interactive && <ChevronRight className="h-4 w-4 shrink-0 text-faint" aria-hidden />}
    </>
  );

  if (href && !disabled) {
    return (
      <Link href={href} className={cn(rowClasses, interactiveClasses)}>
        {inner}
      </Link>
    );
  }

  if (onClick && !disabled) {
    return (
      <button type="button" onClick={onClick} className={cn(rowClasses, interactiveClasses)}>
        {inner}
      </button>
    );
  }

  return <div className={cn(rowClasses, disabled && 'opacity-45')}>{inner}</div>;
}

/**
 * A row carrying a switch. The label is the control's accessible name, so the
 * whole row is one tap target rather than a label and a separate 20px switch.
 */
export function SettingsToggle({
  label,
  hint,
  checked,
  onChange,
  disabled,
}: {
  label: string;
  hint?: string;
  checked: boolean;
  onChange: (next: boolean) => void;
  disabled?: boolean;
}) {
  return (
    <button
      type="button"
      role="switch"
      aria-checked={checked}
      disabled={disabled}
      onClick={() => onChange(!checked)}
      className={cn(
        rowClasses,
        interactiveClasses,
        disabled && 'pointer-events-none opacity-45',
      )}
    >
      <span className="min-w-0 flex-1">
        <span className="block text-body-sm text-strong">{label}</span>
        {hint && <span className="mt-0.5 block text-meta text-muted">{hint}</span>}
      </span>
      <span
        aria-hidden
        className={cn(
          'relative h-[1.6rem] w-[2.75rem] shrink-0 rounded-pill',
          'transition-colors duration-[120ms] ease-standard',
          // ink-500, not ink-300: an off switch is a UI component and owes 3:1
          // against the row behind it (§8). ink-300 measured 1.78:1 on white,
          // which made "off" read as "disabled" as much as it read as a state.
          checked ? 'bg-brand-500' : 'bg-ink-500',
        )}
      >
        <span
          className={cn(
            'absolute top-[0.2rem] h-[1.2rem] w-[1.2rem] rounded-pill bg-white shadow-sm',
            'transition-[left] duration-[120ms] ease-standard',
            checked ? 'left-[1.35rem]' : 'left-[0.2rem]',
          )}
        />
      </span>
    </button>
  );
}