import * as React from 'react';
import { cn } from '@/lib/utils';

/**
 * Renders the light markup the capabilities emit — `**bold**`, bullets,
 * numbered items, `_asides_`, and ✓/⚠ check lines.
 *
 * A full markdown renderer is available in the project, but this content is
 * produced locally in a known shape, and parsing five constructs keeps the
 * assistant's typography inside the design system rather than inheriting a
 * library's defaults.
 */

const BOLD = /\*\*(.+?)\*\*/g;

function inline(line, keyPrefix) {
  const parts = [];
  let last = 0;
  let match;
  BOLD.lastIndex = 0;

  while ((match = BOLD.exec(line)) !== null) {
    if (match.index > last) parts.push(line.slice(last, match.index));
    parts.push(
      <strong key={`${keyPrefix}-${match.index}`} className="font-semibold text-ink-1">
        {match[1]}
      </strong>
    );
    last = match.index + match[0].length;
  }
  if (last < line.length) parts.push(line.slice(last));
  return parts.length ? parts : line;
}

export function RichText({ text, className }) {
  const lines = React.useMemo(() => String(text).split('\n'), [text]);

  return (
    <div className={cn('space-y-1.5 text-body-sm text-ink-2', className)}>
      {lines.map((line, i) => {
        if (!line.trim()) return <div key={i} className="h-1.5" aria-hidden="true" />;

        /* Aside — a caveat the capabilities wrap in underscores. */
        if (line.startsWith('_') && line.endsWith('_')) {
          return (
            <p key={i} className="border-l-2 border-border pl-2.5 text-caption italic text-ink-3 leading-relaxed">
              {inline(line.slice(1, -1), i)}
            </p>
          );
        }

        /* Bullet. */
        if (line.startsWith('• ')) {
          return (
            <div key={i} className="flex gap-2 leading-relaxed">
              <span className="text-krow-blue shrink-0" aria-hidden="true">•</span>
              <span className="min-w-0">{inline(line.slice(2), i)}</span>
            </div>
          );
        }

        /* Indented continuation of a numbered item. */
        if (line.startsWith('   ')) {
          return (
            <p key={i} className="pl-6 text-caption text-ink-3 leading-relaxed">
              {inline(line.trim(), i)}
            </p>
          );
        }

        /* Numbered item. */
        const numbered = line.match(/^(\d+)\.\s+(.*)$/);
        if (numbered) {
          return (
            <div key={i} className="flex gap-2.5 leading-relaxed">
              <span className="grid place-items-center w-4 h-4 mt-0.5 shrink-0 rounded-full bg-krow-blue-tint text-[10px] font-bold text-krow-blue">
                {numbered[1]}
              </span>
              <span className="min-w-0">{inline(numbered[2], i)}</span>
            </div>
          );
        }

        /* Health-check line. */
        if (line.startsWith('✓ ') || line.startsWith('⚠ ')) {
          const ok = line.startsWith('✓');
          return (
            <div key={i} className="flex gap-2 leading-relaxed">
              <span className={cn('shrink-0 font-semibold', ok ? 'text-success' : 'text-warning')} aria-hidden="true">
                {ok ? '✓' : '⚠'}
              </span>
              <span className="min-w-0">{inline(line.slice(2), i)}</span>
            </div>
          );
        }

        return <p key={i} className="leading-relaxed">{inline(line, i)}</p>;
      })}
    </div>
  );
}

/** The three-dot indicator shown before the first delta arrives. */
export function ThinkingIndicator() {
  return (
    <div className="inline-flex items-center gap-1 rounded-xl rounded-tl-sm border border-border bg-surface px-3 py-2.5 shadow-xs">
      {[0, 1, 2].map((i) => (
        <span
          key={i}
          className="w-1.5 h-1.5 rounded-full bg-ink-4 animate-typing"
          style={{ animationDelay: `${i * 0.18}s` }}
        />
      ))}
      <span className="sr-only">Assistant is thinking</span>
    </div>
  );
}

/**
 * One turn in the conversation. The user's own words sit in a filled bubble; the
 * assistant's answer runs full width, because these answers are structured
 * multi-paragraph reports and a chat bubble would waste a third of a 380px
 * column on padding.
 */
export function Message({ role, text, streaming, stopped }) {
  if (role === 'user') {
    return (
      <div className="flex justify-end animate-slide-up">
        <div className="max-w-[85%] rounded-xl rounded-br-sm bg-krow-blue px-3 py-2 text-body-sm text-white">
          {text}
        </div>
      </div>
    );
  }

  return (
    <div className="animate-slide-up">
      <RichText text={text} />
      {streaming && (
        <span
          className="inline-block w-1.5 h-3.5 ml-0.5 -mb-0.5 bg-krow-blue animate-caret"
          aria-hidden="true"
        />
      )}
      {stopped && (
        <p className="mt-1.5 text-caption italic text-ink-4">Stopped early.</p>
      )}
    </div>
  );
}