background.js

// FFSleep Background Script
const api = (typeof browser !== 'undefined') ? browser : chrome;

const DEFAULT_SETTINGS = {
    autoSleepEnabled: false,
    autoSleepMinutes: 30,
    whitelist: [],
    totalMemorySavedMB: 0,
    tabActivity: {} // { tabId: lastActiveTimeStamp }
};

// Initialize settings
api.runtime.onInstalled.addListener(async () => {
    const data = await api.storage.local.get('settings');
    if (!data.settings) {
        await api.storage.local.set({ settings: DEFAULT_SETTINGS });
    }
    setupAlarm();
});

// Setup or Clear Alarm based on settings
async function setupAlarm() {
    const { settings } = await api.storage.local.get('settings');
    await api.alarms.clear('autoSleepCheck');

    if (settings.autoSleepEnabled) {
        // Check every minute
        api.alarms.create('autoSleepCheck', { periodInMinutes: 1 });
    }
}

// Listen for storage changes to update alarm
api.storage.onChanged.addListener((changes, area) => {
    if (area === 'local' && changes.settings) {
        setupAlarm();
    }
});

// Track tab activity
api.tabs.onActivated.addListener((activeInfo) => {
    updateTabActivity(activeInfo.tabId);
});

async function updateTabActivity(tabId) {
    const { settings } = await api.storage.local.get('settings');
    settings.tabActivity = settings.tabActivity || {};
    settings.tabActivity[tabId] = Date.now();
    await api.storage.local.set({ settings });
}

// Alarm Listener: Check for idle tabs
api.alarms.onAlarm.addListener(async (alarm) => {
    if (alarm.name === 'autoSleepCheck') {
        await checkAndSleepTabs();
    }
});

async function checkAndSleepTabs() {
    const { settings } = await api.storage.local.get('settings');
    if (!settings.autoSleepEnabled) return;

    const tabs = await api.tabs.query({ active: false, discarded: false });
    const now = Date.now();
    const thresholdMs = settings.autoSleepMinutes * 60 * 1000;

    const discardedIds = [];

    for (const tab of tabs) {
        // Skip hidden/system tabs
        if (!tab.url || tab.url.startsWith('about:')) continue;

        // Check Whitelist
        const isWhitelisted = settings.whitelist.some(domain => tab.url.includes(domain));
        if (isWhitelisted) continue;

        const lastActive = settings.tabActivity[tab.id] || 0;

        // If tab hasn't been active for threshold time
        if (now - lastActive > thresholdMs) {
            discardedIds.push(tab.id);
        }
    }

    if (discardedIds.length > 0) {
        await api.tabs.discard(discardedIds);

        // Update stats: Assuming average 75MB per tab
        settings.totalMemorySavedMB += (discardedIds.length * 75);
        await api.storage.local.set({ settings });

        // Optional: Notify user
        // api.notifications.create({
        //     type: 'basic',
        //     iconUrl: 'icons/icon.svg',
        //     title: 'FFSleep',
        //     message: `${discardedIds.length} tabs were put to sleep automatically.`
        // });
    }
}

// Clean up activity log when tabs are closed
api.tabs.onRemoved.addListener(async (tabId) => {
    const { settings } = await api.storage.local.get('settings');
    if (settings.tabActivity && settings.tabActivity[tabId]) {
        delete settings.tabActivity[tabId];
        await api.storage.local.set({ settings });
    }
});