import '../../styles/studio-assistant.css';

import { ImageIcon, MessageSquare } from 'lucide-react';
import { type HTMLAttributes, type KeyboardEvent, useCallback, useEffect, useRef, useState } from 'react';
import { useNavigate } from 'react-router';

import { useTranslation } from '../../i18n';
import { useAssistantStore } from '../../store/assistantStore';
import AssistantHeader from '../Assistant/AssistantHeader';
import AssistantSurfaceLazy from '../Assistant/AssistantSurfaceLazy';
import type { EntityTarget } from '../Assistant/cards/cardTypes';
import { providerLabel } from '../Assistant/providerCatalog';
import { useAssistantThread } from '../Assistant/useAssistantThread';
import { useToast } from '../shared/Toast';
import { SpreadView } from './SpreadView';
import { sheetSizePx } from './pageSnapshot';
import type { StudioAssistant, StudioRenderJob } from './useStudioAssistant';

/**
 * The assistant as a column of TREK Studio (journey-studio.md 4.5): the same
 * chat as the planner's window, on the journey's conversations, beside the
 * page it talks about. Desktop only, like the Studio itself.
 *
 * Studio closes on Escape and edits the selection on Delete, copy and paste.
 * Inside the column every key belongs to the chat, so it stops here, and
 * Escape stops a running answer first. A key from the header's menu, which
 * sits in a portal, is not the chat's to act on.
 */

/** The column is not a window: its head moves nothing. */
const NO_DRAG: HTMLAttributes<HTMLElement> = { style: { cursor: 'default' } };

/**
 * Images of a page leave only once the user agreed, per connection. Until
 * then the Studio's assistant reads the pages as text. "Not now" hides the
 * notice for this visit; the next one asks again. A model that reads no
 * images (a custom server, OpenRouter, an OpenAI text-only model) is never
 * asked: its pages always go as text.
 */
function StudioImagesNotice() {
  const { t } = useTranslation();
  const toast = useToast();
  const effective = useAssistantStore((s) => s.status?.effective ?? null);
  const reads = useAssistantStore((s) => s.status?.studioImages === true);
  const acked = useAssistantStore((s) => s.status?.studioImagesAcked === true);
  const ackStudioImages = useAssistantStore((s) => s.ackStudioImages);
  const [later, setLater] = useState(false);

  if (!effective || !reads || acked || later) return null;
  const provider = providerLabel(effective.kind, effective.host);

  const allow = async () => {
    try {
      await ackStudioImages();
    } catch {
      toast.error(t('assistant.error.generic'));
    }
  };

  return (
    <div
      role="note"
      className="st-assistant-notice rounded-lg border border-edge-faint bg-surface-secondary px-3 py-2.5 text-caption text-content-secondary"
    >
      <div className="flex items-start gap-2.5">
        <ImageIcon size={14} aria-hidden="true" className="mt-0.5 flex-shrink-0 text-content-muted" />
        <p className="m-0 min-w-0 flex-1">{t('journey.studio.assistant.notice', { provider })}</p>
      </div>
      <div className="mt-2 flex items-center justify-end gap-1">
        <button
          type="button"
          onClick={() => setLater(true)}
          className="rounded-md px-2 py-1 text-caption text-content-muted hover:bg-surface-hover hover:text-content"
        >
          {t('journey.studio.assistant.noticeLater')}
        </button>
        <button
          type="button"
          onClick={() => void allow()}
          className="rounded-md px-2 py-1 text-caption font-medium text-accent-on hover:bg-surface-hover"
        >
          {t('journey.studio.assistant.noticeAllow')}
        </button>
      </div>
    </div>
  );
}

/** One page a turn asked for, drawn as the editor draws it and handed on once it is in the DOM. */
function StageSheet({
  job,
  onDrawn,
}: {
  job: StudioRenderJob;
  onDrawn: (job: StudioRenderJob, sheet: HTMLElement) => Promise<void>;
}) {
  const sheet = useRef<HTMLDivElement>(null);
  // A job goes up once, even when the effect runs again (development's double run, a new callback).
  const sent = useRef<StudioRenderJob | null>(null);
  const size = sheetSizePx(job.spread, job.page);

  useEffect(() => {
    if (!sheet.current || sent.current === job) return;
    sent.current = job;
    void onDrawn(job, sheet.current);
  }, [job, onDrawn]);

  return (
    // A page is laid out in millimetres from its top left whatever the reading direction.
    <div ref={sheet} dir="ltr" style={{ position: 'relative', width: size.width, height: size.height }}>
      <SpreadView spread={job.spread} page={job.page} folios={job.folios} print hiddenPhotoIds={job.hidden} />
    </div>
  );
}

/**
 * The pages being drawn for a turn, where nobody sees them. Off screen rather
 * than hidden, as StudioExport does it: a hidden subtree lays nothing out,
 * and the page is measured in millimetres by the CSS that draws it.
 */
export function StudioPageStage({ assistant }: { assistant: StudioAssistant }) {
  if (assistant.jobs.length === 0) return null;
  return (
    <div
      aria-hidden="true"
      className="st-assistant-stage"
      style={{ position: 'fixed', insetInlineStart: '-20000mm', top: 0, pointerEvents: 'none' }}
    >
      {assistant.jobs.map((job) => (
        <StageSheet key={job.request.requestId} job={job} onDrawn={assistant.drawn} />
      ))}
    </div>
  );
}

export default function StudioAssistantPanel({
  assistant,
  title,
  bookVersion,
}: {
  assistant: StudioAssistant;
  title: string;
  /** The stored book's version the open book stands on, for the book's cards in the chat. */
  bookVersion?: number | null;
}) {
  const { t } = useTranslation();
  const navigate = useNavigate();
  const thread = useAssistantThread(assistant.chatKey);
  const { isRunning, stop } = thread;

  // A card points at a page of this book (`?page=`) or somewhere else in the app.
  const onOpen = useCallback(
    (target: EntityTarget) => {
      if (target.kind === 'page') void navigate(target.path);
    },
    [navigate]
  );

  // Every key pressed in the column is the chat's: the editor's own keys
  // (Delete, Backspace, copy, paste, undo, Escape) listen on the window and
  // would otherwise act on the page's selection from a focused chat button.
  // Keys from a portal (the header's menu) bubble here through React too;
  // they stop here as well, but they are not the chat's to act on.
  const onKeyDown = (e: KeyboardEvent<HTMLElement>) => {
    const inside = e.currentTarget.contains(e.target as Node);
    e.stopPropagation();
    if (inside && e.key === 'Escape' && isRunning && !e.defaultPrevented) stop();
  };

  return (
    <aside className="st-panel st-assistant" aria-label={t('journey.studio.assistant.panel')} onKeyDown={onKeyDown}>
      <AssistantHeader
        tripId={assistant.chatKey}
        thread={thread}
        tripTitle={title}
        dragProps={NO_DRAG}
        onClose={assistant.toggle}
      />
      <StudioImagesNotice />
      <AssistantSurfaceLazy
        tripId={assistant.chatKey}
        tripTitle={title}
        variant="window"
        density="compact"
        onOpen={onOpen}
        bookVersion={bookVersion}
      />
    </aside>
  );
}

/** The Studio bar's switch for the column; only where the assistant can run for this user. */
export function StudioAssistantToggle({ assistant }: { assistant: StudioAssistant }) {
  const { t } = useTranslation();
  if (!assistant.available) return null;
  return (
    <button
      type="button"
      className={`st-tool st-assistant-toggle ${assistant.open ? 'is-on' : ''}`}
      onClick={assistant.toggle}
      aria-pressed={assistant.open}
      title={t('journey.studio.assistant.toggleHint')}
    >
      <MessageSquare size={14} />
      <span className="st-tool-label">{t('journey.studio.assistant.toggle')}</span>
    </button>
  );
}

/** The chat column at the end of the Studio's body, while it is open, named after the journey. */
export function StudioAssistantColumn({
  assistant,
  title,
  bookVersion,
}: {
  assistant: StudioAssistant;
  title?: string;
  bookVersion?: number | null;
}) {
  const { t } = useTranslation();
  if (!assistant.open) return null;
  return <StudioAssistantPanel assistant={assistant} title={title || t('journey.title')} bookVersion={bookVersion} />;
}