// ── History Loading ──

let lastKnownMessageId = 0;
let historyPollInterval = null;
let loadedArchiveCount = 0;

async function loadHistory() {
  try {
    const sid = getCurrentSessionId();
    const archives = await apiListArchives(sid);
    if (archives.length > 0) {
      showArchiveLoadButton();
    }

    const data = await apiHistory(sid);
    data.reverse();

    for (const entry of data) {
      renderMessages(entry.messages, true);
    }

    scrollDown();
    startHistoryPolling();
  } catch (e) {
    console.error('History laden fehlgeschlagen:', e);
  }
}

function renderMessages(msgs, addToConversation) {
  for (const msg of msgs) {
    if (msg.id > lastKnownMessageId) lastKnownMessageId = msg.id;

    switch (msg.type) {
      case 'text':
        if (msg.role === 'user') {
          addUserBubble(msg.content);
          if (addToConversation) messages.push({ role: 'user', content: msg.content });
        } else if (msg.role === 'assistant') {
          addAssistantBubble(msg.content);
          if (addToConversation) messages.push({ role: 'assistant', content: msg.content });
        }
        break;

      case 'tool_use':
        addToolBoxStatic(msg.toolName, msg.content, null, false);
        break;

      case 'tool_result':
        addToolBoxStatic(null, null, msg.content, msg.isError);
        break;

      case 'error':
        addErrorBubble(msg.content);
        break;
    }
  }
}

// ── Archive Loading ──

function getOrCreateArchiveContainer() {
  let container = chatEl().querySelector('.archive-container');
  if (!container) {
    container = document.createElement('div');
    container.className = 'archive-container';
    chatEl().prepend(container);
  }
  return container;
}

function getOrCreateArchiveDivider() {
  let divider = chatEl().querySelector('.archive-divider');
  if (!divider) {
    divider = document.createElement('div');
    divider.className = 'msg system-info archive-divider';
    divider.textContent = '── Aktuelle Konversation ──';
    // Nach dem Container, vor den aktiven Messages
    const container = getOrCreateArchiveContainer();
    container.after(divider);
  }
  return divider;
}

async function loadLatestArchive() {
  try {
    const archives = await apiListArchives(getCurrentSessionId());
    if (archives.length <= loadedArchiveCount) return;

    const latest = archives[loadedArchiveCount];
    loadedArchiveCount++;

    removeArchiveLoadButton();

    const data = await apiGetArchive(latest.archiveId);
    const container = getOrCreateArchiveContainer();
    getOrCreateArchiveDivider();

    // Archiv-Block zusammenbauen
    const fragment = document.createDocumentFragment();

    const sep = document.createElement('div');
    sep.className = 'msg system-info';
    sep.textContent = `📦 Archiv vom ${new Date(latest.createdAt).toLocaleString('de-AT')} (${latest.chainCount} Chains, ${latest.messageCount} Messages)`;
    fragment.appendChild(sep);

    for (const entry of data) {
      for (const msg of entry.messages) {
        const div = document.createElement('div');
        switch (msg.type) {
          case 'text':
            div.className = msg.role === 'user' ? 'msg user archived' : 'msg assistant archived';
            div.textContent = msg.content;
            break;
          case 'tool_use':
            div.className = 'tool-box archived';
            div.innerHTML = '<span class="tool-name">' + esc(msg.toolName) + '</span>'
              + '<span class="tool-input">' + esc(truncate(msg.content, 120)) + '</span>';
            break;
          case 'tool_result':
            div.className = 'tool-box archived';
            div.innerHTML = '<div class="tool-result ' + (msg.isError ? 'tool-error' : '') + '">'
              + esc(truncate(msg.content, 300)) + '</div>';
            break;
          case 'error':
            div.className = 'msg system-info archived';
            div.style.color = '#ff6b6b';
            div.textContent = msg.content;
            break;
          default:
            continue;
        }
        fragment.appendChild(div);
      }
    }

    // Älteres Archiv vor dem bisherigen Inhalt einfügen
    container.prepend(fragment);

    // Button ganz oben, falls es noch ältere Archive gibt
    if (archives.length > loadedArchiveCount) {
      showArchiveLoadButton();
    }

  } catch (e) {
    console.error('Archiv laden fehlgeschlagen:', e);
  }
}

// ── Polling ──

function startHistoryPolling(intervalMs = 3000) {
  if (historyPollInterval) return;
  historyPollInterval = setInterval(pollHistory, intervalMs);
}

function stopHistoryPolling() {
  if (historyPollInterval) {
    clearInterval(historyPollInterval);
    historyPollInterval = null;
  }
}

async function pollHistory() {
  if (isStreaming) return;

  try {
    const newMessages = await apiHistoryPoll(getCurrentSessionId(), lastKnownMessageId);
    if (newMessages.length > 0) {
      renderMessages(newMessages, true);
      scrollDown();
    }
  } catch (e) {
    console.error('History poll fehlgeschlagen:', e);
  }
}