'use client';

import { useState } from 'react';
import { useRouter } from 'next/navigation';
import type { NovelQueueItem } from '@/lib/db/queries';

interface Props {
  queue: NovelQueueItem[];
}

interface LabelFormState {
  tag: string;
  signature: string;
  description: string;
  correction: string;
  addGolden: boolean;
}

function EvidenceHighlight({ text, span }: { text: string; span: string }) {
  if (!span || !text.includes(span)) {
    return <span style={s.responseText}>{text}</span>;
  }
  const idx = text.indexOf(span);
  return (
    <span style={s.responseText}>
      {text.slice(0, idx)}
      <mark style={s.evidenceMark}>{span}</mark>
      {text.slice(idx + span.length)}
    </span>
  );
}

function QueueCard({ item, onProcessed }: { item: NovelQueueItem; onProcessed: () => void }) {
  const [busy, setBusy] = useState(false);
  const [expanded, setExpanded] = useState(false);
  const [form, setForm] = useState<LabelFormState>({
    tag: '',
    signature: item.evidenceSpan,
    description: '',
    correction: '',
    addGolden: false,
  });
  const [msg, setMsg] = useState<string | null>(null);

  const label = async () => {
    if (!form.tag.trim() || !form.signature.trim()) return;
    if (!item.conceptId) { setMsg('No concept linked — cannot label.'); return; }
    setBusy(true);
    setMsg(null);
    const res = await fetch('/api/admin/misconceptions', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        action: 'label',
        queueId: item.id,
        conceptId: item.conceptId,
        tag: form.tag.trim(),
        signature: form.signature.trim(),
        description: form.description.trim() || undefined,
        correction: form.correction.trim() || undefined,
        addGolden: form.addGolden,
        goldenData: form.addGolden ? {
          responseText: item.responseText,
          expectedTag: form.tag.trim(),
          conceptId: item.conceptId,
        } : undefined,
      }),
    });
    setBusy(false);
    if (res.ok) { onProcessed(); } else { setMsg('Label failed — check server logs.'); }
  };

  const dismiss = async () => {
    setBusy(true);
    await fetch('/api/admin/misconceptions', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ action: 'dismiss', queueId: item.id }),
    });
    setBusy(false);
    onProcessed();
  };

  return (
    <div style={s.card}>
      <div style={s.cardHead}>
        <div>
          <span style={s.conceptTag}>{item.conceptName ?? 'Unknown concept'}</span>
          <span style={s.timestamp}>{new Date(item.createdAt).toLocaleDateString()}</span>
        </div>
        <div style={s.actionRow}>
          <button style={s.labelBtn} disabled={busy} onClick={() => setExpanded((e) => !e)}>
            {expanded ? 'Collapse' : 'Label'}
          </button>
          <button style={s.dismissBtn} disabled={busy} onClick={() => void dismiss()}>
            {busy ? '…' : 'Dismiss'}
          </button>
        </div>
      </div>

      <p style={s.checkpointPrompt}>{item.checkpointPrompt}</p>

      <div style={s.responsePre}>
        <EvidenceHighlight text={item.responseText} span={item.evidenceSpan} />
      </div>

      {item.existingMisconceptions.length > 0 && (
        <details style={s.details}>
          <summary style={s.summary}>Existing misconceptions for this concept ({item.existingMisconceptions.length})</summary>
          <ul style={s.miscList}>
            {item.existingMisconceptions.map((m) => (
              <li key={m.id} style={s.miscItem}>
                <code>{m.tag}</code> — {m.signature}
              </li>
            ))}
          </ul>
        </details>
      )}

      {expanded && (
        <div style={s.labelForm}>
          <label style={s.fieldLabel}>
            Tag (short slug, e.g. <code>scope-confusion</code>)
            <input
              style={s.input}
              value={form.tag}
              onChange={(e) => setForm((f) => ({ ...f, tag: e.target.value }))}
              placeholder="e.g. scope-confusion"
            />
          </label>
          <label style={s.fieldLabel}>
            Signature (text pattern that reveals this)
            <input
              style={s.input}
              value={form.signature}
              onChange={(e) => setForm((f) => ({ ...f, signature: e.target.value }))}
            />
          </label>
          <label style={s.fieldLabel}>
            Description (what the learner wrongly believes)
            <input
              style={s.input}
              value={form.description}
              onChange={(e) => setForm((f) => ({ ...f, description: e.target.value }))}
              placeholder="Optional"
            />
          </label>
          <label style={s.fieldLabel}>
            Correction (brief guidance for the tutor)
            <input
              style={s.input}
              value={form.correction}
              onChange={(e) => setForm((f) => ({ ...f, correction: e.target.value }))}
              placeholder="Optional"
            />
          </label>
          <label style={{ ...s.fieldLabel, flexDirection: 'row', alignItems: 'center', gap: 'var(--space-2)' }}>
            <input
              type="checkbox"
              checked={form.addGolden}
              onChange={(e) => setForm((f) => ({ ...f, addGolden: e.target.checked }))}
            />
            Also add as golden eval case
          </label>
          {msg && <p style={s.error}>{msg}</p>}
          <button
            style={s.saveBtn}
            disabled={busy || !form.tag.trim() || !form.signature.trim()}
            onClick={() => void label()}
          >
            {busy ? 'Saving…' : 'Save misconception'}
          </button>
        </div>
      )}
    </div>
  );
}

export default function MisconceptionsClient({ queue }: Props) {
  const router = useRouter();
  const [items, setItems] = useState(queue);

  const markProcessed = (id: string) => {
    setItems((prev) => prev.filter((i) => i.id !== id));
    router.refresh();
  };

  return (
    <div>
      <h1 style={s.heading}>Novel Misconceptions Queue</h1>
      <p style={s.sub}>
        {items.length === 0
          ? 'Queue is empty — all novel responses have been reviewed.'
          : `${items.length} unprocessed response${items.length !== 1 ? 's' : ''} — label or dismiss each.`}
      </p>

      {items.map((item) => (
        <QueueCard key={item.id} item={item} onProcessed={() => markProcessed(item.id)} />
      ))}
    </div>
  );
}

const s = {
  heading: { fontFamily: 'var(--font-display)', fontSize: '1.5rem', fontWeight: 500, color: 'var(--color-ink)', marginBottom: 'var(--space-2)' },
  sub: { fontFamily: 'var(--font-display)', fontSize: '0.9375rem', color: 'var(--color-ink-muted)', marginBottom: 'var(--space-8)' },
  card: { border: '1px solid var(--color-border)', borderRadius: '6px', padding: 'var(--space-5)', marginBottom: 'var(--space-4)' },
  cardHead: { display: 'flex', justifyContent: 'space-between', alignItems: 'flex-start', gap: 'var(--space-3)', marginBottom: 'var(--space-3)', flexWrap: 'wrap' as const },
  conceptTag: { fontFamily: 'var(--font-display)', fontSize: '0.8125rem', fontWeight: 600, color: 'var(--color-accent)', textTransform: 'uppercase' as const, letterSpacing: '0.06em' },
  timestamp: { fontFamily: 'var(--font-display)', fontSize: '0.75rem', color: 'var(--color-ink-faint)', marginLeft: 'var(--space-3)' },
  actionRow: { display: 'flex', gap: 'var(--space-2)' },
  checkpointPrompt: { fontFamily: 'var(--font-body)', fontSize: '0.9375rem', color: 'var(--color-ink-muted)', fontStyle: 'italic', marginBottom: 'var(--space-3)' },
  responsePre: { fontFamily: 'var(--font-body)', fontSize: '0.9375rem', lineHeight: 1.65, color: 'var(--color-ink)', background: 'var(--color-surface)', border: '1px solid var(--color-border-subtle)', borderRadius: '4px', padding: 'var(--space-3)', marginBottom: 'var(--space-3)' },
  responseText: { whiteSpace: 'pre-wrap' as const },
  evidenceMark: { background: 'var(--color-misconception-subtle)', color: 'var(--color-misconception)', borderBottom: '2px solid var(--color-misconception)', padding: '0 2px', borderRadius: '2px' },
  details: { marginBottom: 'var(--space-3)' },
  summary: { fontFamily: 'var(--font-display)', fontSize: '0.8125rem', color: 'var(--color-ink-muted)', cursor: 'pointer' },
  miscList: { listStyle: 'none', padding: 0, margin: 'var(--space-2) 0 0' },
  miscItem: { fontFamily: 'var(--font-display)', fontSize: '0.8125rem', color: 'var(--color-ink-muted)', marginBottom: 'var(--space-1)' },
  labelForm: { borderTop: '1px solid var(--color-border-subtle)', paddingTop: 'var(--space-4)', marginTop: 'var(--space-3)', display: 'flex', flexDirection: 'column' as const, gap: 'var(--space-3)' },
  fieldLabel: { display: 'flex', flexDirection: 'column' as const, gap: 'var(--space-1)', fontFamily: 'var(--font-display)', fontSize: '0.8125rem', color: 'var(--color-ink-muted)' },
  input: { fontFamily: 'var(--font-display)', fontSize: '0.9375rem', color: 'var(--color-ink)', background: 'var(--color-surface)', border: '1px solid var(--color-border)', borderRadius: '4px', padding: 'var(--space-2) var(--space-3)', width: '100%' },
  error: { color: 'var(--color-misconception)', fontSize: '0.875rem' },
  labelBtn: { padding: 'var(--space-1) var(--space-3)', background: 'var(--color-accent-subtle)', color: 'var(--color-accent)', border: '1px solid var(--color-accent)', borderRadius: '4px', cursor: 'pointer', fontSize: '0.8125rem' },
  dismissBtn: { padding: 'var(--space-1) var(--space-3)', background: 'var(--color-surface)', color: 'var(--color-ink-muted)', border: '1px solid var(--color-border)', borderRadius: '4px', cursor: 'pointer', fontSize: '0.8125rem' },
  saveBtn: { alignSelf: 'flex-start', padding: 'var(--space-2) var(--space-5)', background: 'var(--color-accent)', color: 'var(--color-on-accent)', border: 'none', borderRadius: '4px', cursor: 'pointer', fontFamily: 'var(--font-display)', fontSize: '0.9375rem', fontWeight: 500 },
} as const;