import { markArweaveAttachmentPlaced, openArweaveAttachmentManager } from './arweave-attachment-manager.js';
import { composeMessageWithAttachments, MAX_MESSAGE_ATTACHMENTS } from '../services/attachment-format.js';
import { state } from '../state.js';
import { toUserMessage } from '../services/ui-error-texts.js';
import { renderUserAvatar } from './avatar-image.js';
import { openAuthRequiredModal } from '../services/auth-required-modal.js';

const drafts = new Map();

function draftKey(key) {
  const login = String(state.session.login || 'guest').trim().toLowerCase();
  return `${login}:${String(key || 'editor')}`;
}

function attachmentLabel(item) {
  const name = String(item?.name || 'Файл');
  const size = Number(item?.size || 0);
  if (!size) return name;
  if (size < 1024) return `${name} · ${size} Б`;
  if (size < 1024 * 1024) return `${name} · ${Math.ceil(size / 1024)} КБ`;
  return `${name} · ${(size / 1024 / 1024).toFixed(1)} МБ`;
}

export function openChannelEditor({
  id = 'channel-editor',
  title = 'Ответ',
  submitLabel = 'Ответить',
  placeholder = 'Напишите ответ',
  context = null,
  key = 'reply',
  extraControl = null,
  initialText = '',
  allowEmptyText = false,
  allowAttachments = true,
  rawText = false,
  onSubmit,
  isActive = () => true,
} = {}) {
  if (!state.session.isAuthorized) {
    openAuthRequiredModal({ title: 'Войдите, чтобы написать', text: 'Для публикации и ответа нужен активный профиль.' });
    return null;
  }
  const root = document.getElementById('modal-root');
  if (!root || typeof onSubmit !== 'function') return null;
  if (root.querySelector('.channel-editor-overlay')) return null;

  const opener = document.activeElement instanceof HTMLElement ? document.activeElement : null;
  const storageKey = draftKey(key);
  const login = state.session.login;
  const saved = drafts.get(storageKey) || { text: initialText, attachments: [] };
  const attachments = Array.isArray(saved.attachments) ? [...saved.attachments] : [];
  const extraFields = extraControl ? [...extraControl.querySelectorAll('select,input')] : [];
  extraFields.forEach((field, index) => {
    if (saved.controls?.[index] !== undefined) field.value = saved.controls[index];
  });
  let inFlight = false;
  let composing = false;
  let closed = false;
  let picking = false;
  let completed = false;
  const attachmentController = new AbortController();

  const overlay = document.createElement('div');
  overlay.className = 'channel-editor-overlay';
  overlay.id = id;
  overlay.setAttribute('role', 'dialog');
  overlay.setAttribute('aria-modal', 'true');
  overlay.setAttribute('aria-labelledby', `${id}-title`);

  const dialog = document.createElement('div');
  dialog.className = 'channel-editor';

  const header = document.createElement('header');
  header.className = 'channel-editor__header';
  const closeButton = document.createElement('button');
  closeButton.type = 'button';
  closeButton.className = 'icon-btn channel-editor__close';
  closeButton.setAttribute('aria-label', 'Закрыть редактор');
  closeButton.textContent = '×';
  const heading = document.createElement('h2');
  heading.id = `${id}-title`;
  heading.textContent = title;
  header.append(closeButton, heading, document.createElement('span'));

  const body = document.createElement('div');
  body.className = 'channel-editor__body';

  if (context && (context.author || context.text || context.attachmentLabel)) {
    const contextBox = document.createElement('div');
    contextBox.className = 'channel-editor__context';
    const contextTitle = document.createElement('strong');
    contextTitle.textContent = context.author ? `В ответ ${context.author}` : 'Контекст сообщения';
    const quote = document.createElement('p');
    quote.textContent = String(context.text || context.attachmentLabel || 'Сообщение без текста');
    const expand = document.createElement('button');
    expand.type = 'button';
    expand.className = 'text-btn channel-editor__context-toggle';
    expand.textContent = 'Показать целиком';
    expand.setAttribute('aria-expanded', 'false');
    expand.addEventListener('click', () => {
      const expanded = contextBox.classList.toggle('is-expanded');
      expand.textContent = expanded ? 'Свернуть' : 'Показать целиком';
      expand.setAttribute('aria-expanded', String(expanded));
    });
    contextBox.append(contextTitle, quote, expand);
    body.append(contextBox);
  }

  const textarea = document.createElement('textarea');
  textarea.className = 'channel-editor__input';
  textarea.maxLength = 2000;
  textarea.placeholder = placeholder;
  textarea.setAttribute('aria-label', placeholder);
  textarea.value = String(saved.text || '');

  const attachmentsBox = document.createElement('div');
  attachmentsBox.className = 'channel-editor__attachments';
  attachmentsBox.setAttribute('aria-live', 'polite');

  const error = document.createElement('p');
  error.className = 'channel-editor__error';
  error.setAttribute('role', 'alert');

  const clearButton = document.createElement('button');
  clearButton.type = 'button';
  clearButton.className = 'text-btn channel-editor__clear';
  clearButton.textContent = 'Очистить черновик';

  const author = document.createElement('div');
  author.className = 'channel-editor__author';
  author.append(renderUserAvatar({ login: login || 'guest', className: 'avatar-plain', size: 'md' }));
  const authorName = document.createElement('strong');
  authorName.textContent = login || 'Гость';
  author.append(authorName);
  body.append(author);
  if (extraControl instanceof Node) body.append(extraControl);
  body.append(textarea, attachmentsBox, error, clearButton);

  const footer = document.createElement('footer');
  footer.className = 'channel-editor__footer';
  const attachButton = document.createElement('button');
  attachButton.type = 'button';
  attachButton.className = 'secondary-btn channel-editor__attach';
  attachButton.textContent = 'Прикрепить';
  attachButton.hidden = !allowAttachments;
  const counter = document.createElement('span');
  counter.className = 'channel-editor__counter';
  const submitButton = document.createElement('button');
  submitButton.type = 'button';
  submitButton.className = 'primary-btn channel-editor__submit';
  submitButton.textContent = submitLabel;
  submitButton.title = 'Отправить · Ctrl+Enter / ⌘+Enter';
  footer.append(attachButton);
  footer.append(counter, submitButton);
  dialog.append(header, body, footer);
  overlay.append(dialog);
  root.replaceChildren(overlay);

  const saveDraft = () => {
    const value = { text: textarea.value, attachments: [...attachments], controls: extraFields.map((field) => field.value) };
    if (completed) { drafts.delete(storageKey); return; }
    if (value.text || value.attachments.length) drafts.set(storageKey, value);
    else drafts.delete(storageKey);
  };

  const sync = () => {
    textarea.style.height = 'auto';
    textarea.style.height = `${Math.max(160, textarea.scrollHeight)}px`;
    const length = textarea.value.length;
    counter.textContent = `${length} / 2000`;
    counter.classList.toggle('is-near-limit', length >= 1800);
    submitButton.disabled = inFlight || picking || length > textarea.maxLength || (!allowEmptyText && !textarea.value.trim() && attachments.length === 0);
    dialog.setAttribute('aria-busy', String(inFlight || picking));
    clearButton.hidden = !textarea.value && attachments.length === 0;
    attachmentsBox.replaceChildren();
    attachments.forEach((item, index) => {
      const card = document.createElement('div');
      card.className = 'channel-editor__attachment';
      const label = document.createElement('span');
      label.textContent = attachmentLabel(item);
      const remove = document.createElement('button');
      remove.type = 'button';
      remove.className = 'icon-btn';
      remove.setAttribute('aria-label', `Убрать вложение ${item?.name || ''}`);
      remove.textContent = '×';
      remove.disabled = inFlight;
      remove.addEventListener('click', () => {
        attachments.splice(index, 1);
        saveDraft();
        sync();
      });
      card.append(label, remove);
      attachmentsBox.append(card);
    });
  };

  const openedUrl = location.href;
  const historyId = `${Date.now()}:${Math.random()}`;
  history.pushState({ ...history.state, channelEditor: historyId }, '', openedUrl);
  const viewport = window.visualViewport;
  const updateViewport = () => {
    overlay.style.setProperty('--editor-height', `${viewport?.height || window.innerHeight}px`);
    overlay.style.setProperty('--editor-top', `${viewport?.offsetTop || 0}px`);
  };
  const onBack = (event) => {
    if (closed) return;
    event.stopImmediatePropagation();
    close({ fromHistory: true });
  };
  const observer = new MutationObserver(() => {
    if (!overlay.isConnected) close({ restoreFocus: false });
  });
  const close = ({ fromHistory = false, restoreFocus = true } = {}) => {
    if (closed) return;
    closed = true;
    saveDraft();
    observer.disconnect();
    attachmentController.abort();
    document.removeEventListener('keydown', onDocumentKeydown);
    viewport?.removeEventListener('resize', updateViewport);
    viewport?.removeEventListener('scroll', updateViewport);
    window.removeEventListener('resize', updateViewport);
    window.removeEventListener('popstate', onBack, true);
    overlay.remove();
    if (!fromHistory && location.href === openedUrl && history.state?.channelEditor === historyId) {
      window.addEventListener('popstate', (event) => {
        if (location.href === openedUrl) event.stopImmediatePropagation();
      }, { capture: true, once: true });
      history.back();
    }
    if (restoreFocus && opener?.isConnected) opener.focus({ preventScroll: true });
  };
  overlay.cleanup = () => close({ restoreFocus: false });

  const submit = async () => {
    if (inFlight || submitButton.disabled) return;
    inFlight = true;
    error.textContent = '';
    textarea.disabled = true;
    attachButton.disabled = true;
    clearButton.disabled = true;
    if (extraControl) extraControl.querySelectorAll('select,button,input').forEach((el) => { el.disabled = true; });
    submitButton.textContent = 'Отправляем…';
    sync();
    try {
      await onSubmit({
        text: rawText ? textarea.value.trim() : composeMessageWithAttachments(textarea.value.trim(), attachments),
        attachments: [...attachments],
      });
      completed = true;
      attachments.forEach((item) => markArweaveAttachmentPlaced(login, item));
      // Не удаляем новый черновик, открытый после закрытия отправляющего редактора.
      if (!closed || drafts.get(storageKey)?.text === textarea.value) drafts.delete(storageKey);
      if (!isActive() || closed) return;
      close();
    } catch (submitError) {
      if (!isActive() || closed) return;
      inFlight = false;
      textarea.disabled = false;
      attachButton.disabled = false;
      clearButton.disabled = false;
      if (extraControl) extraControl.querySelectorAll('select,button,input').forEach((el) => { el.disabled = false; });
      submitButton.textContent = submitLabel;
      error.textContent = toUserMessage(submitError, 'Не удалось отправить. Текст сохранён.');
      saveDraft();
      sync();
    }
  };

  const onDocumentKeydown = (event) => {
    if (!overlay.isConnected || document.querySelector('.ar-attachment-manager-root')) return;
    if (event.key === 'Escape') {
      event.preventDefault();
      close();
      return;
    }
    if (event.key === 'Enter' && (event.ctrlKey || event.metaKey) && !composing && !event.isComposing) {
      event.preventDefault();
      void submit();
      return;
    }
    if (event.key !== 'Tab') return;
    const focusable = [...overlay.querySelectorAll('button:not(:disabled), textarea:not(:disabled), select:not(:disabled)')].filter((el) => !el.hidden);
    if (!focusable.length) return;
    const first = focusable[0];
    const last = focusable[focusable.length - 1];
    if (event.shiftKey && document.activeElement === first) {
      event.preventDefault();
      last.focus();
    } else if (!event.shiftKey && document.activeElement === last) {
      event.preventDefault();
      first.focus();
    }
  };

  closeButton.addEventListener('click', () => close());
  clearButton.addEventListener('click', () => {
    textarea.value = '';
    attachments.splice(0);
    drafts.delete(storageKey);
    error.textContent = '';
    sync();
    textarea.focus();
  });
  textarea.addEventListener('input', () => {
    error.textContent = '';
    saveDraft();
    sync();
  });
  textarea.addEventListener('compositionstart', () => { composing = true; });
  extraFields.forEach((field) => field.addEventListener('change', saveDraft));
  textarea.addEventListener('compositionend', () => { composing = false; });
  attachButton.addEventListener('click', async () => {
    if (picking || inFlight) return;
    if (attachments.length >= MAX_MESSAGE_ATTACHMENTS) {
      error.textContent = `Можно прикрепить максимум ${MAX_MESSAGE_ATTACHMENTS} файлов.`;
      return;
    }
    try {
      picking = true;
      dialog.inert = true;
      sync();
      const item = await openArweaveAttachmentManager({
        login,
        storagePwd: state.session.storagePwdInMemory,
        gateway: state.entrySettings.arweaveServer,
        selectedTxIds: attachments.map((attachment) => attachment.ar),
        signal: attachmentController.signal,
      });
      if (!isActive() || !overlay.isConnected || !item) return;
      attachments.push(item);
      saveDraft();
      sync();
    } catch (attachError) {
      if (isActive() && overlay.isConnected) {
        error.textContent = toUserMessage(attachError, 'Не удалось добавить вложение.');
      }
    } finally {
      picking = false;
      dialog.inert = false;
      if (!closed) { sync(); attachButton.focus(); }
    }
  });
  submitButton.addEventListener('click', () => void submit());
  document.addEventListener('keydown', onDocumentKeydown);
  window.addEventListener('popstate', onBack, true);
  viewport?.addEventListener('resize', updateViewport);
  viewport?.addEventListener('scroll', updateViewport);
  window.addEventListener('resize', updateViewport);
  observer.observe(root, { childList: true });
  updateViewport();
  sync();
  requestAnimationFrame(() => {
    if (closed || !isActive()) return;
    const quote = overlay.querySelector('.channel-editor__context p');
    const expand = overlay.querySelector('.channel-editor__context-toggle');
    if (quote && expand && quote.clientHeight > 0) expand.hidden = quote.scrollHeight <= quote.clientHeight;
    sync();
    textarea.focus();
    textarea.setSelectionRange(textarea.value.length, textarea.value.length);
  });
  return { close };
}