background.js

const STARTUP_GRACE_MS = 8000;

chrome.runtime.onStartup.addListener(() => {
  chrome.storage.session.set({ startupTime: Date.now() });
  chrome.alarms.create('startupGrace', { delayInMinutes: STARTUP_GRACE_MS / 60000 });
  console.log('[TabRight] Startup grace period started.');
});

chrome.alarms.onAlarm.addListener((alarm) => {
  if (alarm.name === 'startupGrace') {
    chrome.storage.session.remove('startupTime');
    console.log('[TabRight] Ready.');
  }
});

chrome.runtime.onInstalled.addListener(() => {
  chrome.storage.session.remove('startupTime');
});

function shouldProcess(callback) {
  chrome.storage.session.get('startupTime', ({ startupTime }) => {
    if (!startupTime) { callback(true); return; }
    callback((Date.now() - startupTime) >= STARTUP_GRACE_MS);
  });
}

// Persist last active tab per window — survives service worker restarts
chrome.tabs.onActivated.addListener(({ tabId, windowId }) => {
  chrome.tabs.get(tabId, (tab) => {
    if (chrome.runtime.lastError || !tab) return;
    // Don't record the new blank tab as "last active"
    const url = tab.url || tab.pendingUrl || '';
    if (url === 'chrome://newtab/' || url === '') return;
    chrome.storage.session.set({
      [`lastActive_${windowId}`]: {
        tabId: tab.id,
        index: tab.index,
        groupId: tab.groupId
      }
    });
    console.log('[TabRight] Recorded active tab', tab.id, 'index', tab.index, 'window', windowId);
  });
});

// Also update index when tabs are moved (indices shift)
chrome.tabs.onMoved.addListener((tabId, moveInfo) => {
  chrome.storage.session.get(`lastActive_${moveInfo.windowId}`, (data) => {
    const last = data[`lastActive_${moveInfo.windowId}`];
    if (last && last.tabId === tabId) {
      chrome.storage.session.set({
        [`lastActive_${moveInfo.windowId}`]: { ...last, index: moveInfo.toIndex }
      });
    }
  });
});

chrome.tabs.onCreated.addListener((newTab) => {
  shouldProcess((ready) => {
    if (!ready || newTab.pinned) return;

    const windowId = newTab.windowId;

    if (newTab.openerTabId != null) {
      // Opened from a link — use opener tab
      chrome.tabs.get(newTab.openerTabId, (opener) => {
        if (chrome.runtime.lastError || !opener) return;
        moveTab(newTab, opener.index + 1, windowId, opener.groupId);
      });
      return;
    }

    // Ctrl+T or Ctrl+Shift+T — use persisted last active tab
    chrome.storage.session.get(`lastActive_${windowId}`, (data) => {
      const last = data[`lastActive_${windowId}`];
      if (!last) {
        console.log('[TabRight] No last active tab recorded, skipping.');
        return;
      }
      console.log('[TabRight] Using persisted last active tab', last.tabId, 'index', last.index);
      moveTab(newTab, last.index + 1, windowId, last.groupId);
    });
  });
});

function moveTab(newTab, targetIndex, windowId, sourceGroupId) {
  setTimeout(() => {
    chrome.tabs.get(newTab.id, (tab) => {
      if (chrome.runtime.lastError || !tab) return;
      if (tab.windowId !== windowId) return;

      const alreadyInGroup = tab.groupId !== chrome.tabGroups.TAB_GROUP_ID_NONE;
      const shouldBeInGroup = sourceGroupId !== chrome.tabGroups.TAB_GROUP_ID_NONE;

      const doMove = (callback) => {
        if (tab.index === targetIndex) {
          callback();
          return;
        }
        chrome.tabs.move(newTab.id, { index: targetIndex }, () => {
          if (chrome.runtime.lastError) {
            console.log('[TabRight] Move error:', chrome.runtime.lastError.message);
          } else {
            console.log('[TabRight] Moved to index', targetIndex);
          }
          callback();
        });
      };

      doMove(() => {
        if (shouldBeInGroup && !alreadyInGroup) {
          chrome.tabs.group({ tabIds: [newTab.id], groupId: sourceGroupId }, () => {
            if (chrome.runtime.lastError) {
              console.log('[TabRight] Group error:', chrome.runtime.lastError.message);
            } else {
              console.log('[TabRight] Added tab to group', sourceGroupId);
            }
          });
        }
      });
    });
  }, 150);
}