/** Sqlite persistence for chats + UI state. */

const LS_CHATS = 'swarm_assistent_chats_v1';
const SAVE_DEBOUNCE_MS = 700;

const timers = { chats: new Map(), ui: null };

function normalizeChat(raw) {
  if (!raw || !raw.id) {
    return null;
  }
  return {
    id: String(raw.id),
    title: String(raw.title || 'Новый чат'),
    createdAt: Number(raw.createdAt) || Date.now(),
    updatedAt: Number(raw.updatedAt) || Date.now(),
    messages: Array.isArray(raw.messages) ? raw.messages : [],
    messages_count: Number(raw.messages_count) || (Array.isArray(raw.messages) ? raw.messages.length : 0),
    params: raw.params && typeof raw.params === 'object' ? raw.params : null,
  };
}

export function attachPersist(SA, request = SA.request) {
  async function loadChats() {
    let chats = [];
    try {
      const data = await request('AssistentListChats', { with_messages: true });
      chats = (data?.chats || []).map(normalizeChat).filter(Boolean);
    } catch (e) {
      console.warn('Assistent: disk chats unavailable', e);
      return null;
    }
    return chats.sort((a, b) => (b.updatedAt || 0) - (a.updatedAt || 0));
  }

  async function getChat(id) {
    if (!id) {
      return null;
    }
    const data = await request('AssistentGetChat', { id });
    return normalizeChat(data?.chat);
  }

  async function searchChats(q) {
    const query = String(q || '').trim();
    if (query.length < 2) {
      return [];
    }
    const data = await request('AssistentListChats', { q: query, with_messages: false, limit: 40 });
    return (data?.chats || []).map(normalizeChat).filter(Boolean);
  }

  function saveChat(chat, { immediate = false } = {}) {
    const clean = normalizeChat(chat);
    if (!clean) {
      return Promise.resolve(null);
    }
    const send = () => {
      timers.chats.delete(clean.id);
      return request('AssistentSaveChat', {
        id: clean.id,
        title: clean.title,
        messages: clean.messages,
        params: clean.params,
        createdAt: clean.createdAt,
        updatedAt: clean.updatedAt,
      });
    };
    if (immediate) {
      const pending = timers.chats.get(clean.id);
      if (pending) {
        clearTimeout(pending);
      }
      return send();
    }
    const pending = timers.chats.get(clean.id);
    if (pending) {
      clearTimeout(pending);
    }
    timers.chats.set(clean.id, setTimeout(() => {
      send().catch((e) => console.warn('Assistent: chat save failed', clean.id, e));
    }, SAVE_DEBOUNCE_MS));
    return Promise.resolve(null);
  }

  function deleteChat(id) {
    if (!id) {
      return Promise.resolve(null);
    }
    const pending = timers.chats.get(id);
    if (pending) {
      clearTimeout(pending);
      timers.chats.delete(id);
    }
    return request('AssistentDeleteChat', { id });
  }

  async function loadUiState() {
    try {
      const data = await request('AssistentGetUiState', {});
      const ui = data?.ui_state;
      return ui && typeof ui === 'object' ? ui : null;
    } catch (e) {
      return null;
    }
  }

  function saveUiState(uiState, { immediate = false } = {}) {
    if (!uiState || typeof uiState !== 'object') {
      return Promise.resolve(null);
    }
    const send = () => {
      timers.ui = null;
      return request('AssistentSaveUiState', { ui_state: uiState });
    };
    if (timers.ui) {
      clearTimeout(timers.ui);
      timers.ui = null;
    }
    if (immediate) {
      return send();
    }
    timers.ui = setTimeout(() => {
      send().catch((e) => console.warn('Assistent: ui-state save failed', e));
    }, SAVE_DEBOUNCE_MS);
    return Promise.resolve(null);
  }

  SA.persist = {
    LS_CHATS,
    loadChats,
    getChat,
    searchChats,
    saveChat,
    deleteChat,
    loadUiState,
    saveUiState,
  };
}