/**
 * Tab switching — switchTab, initTabs, startAutoRefresh, hash routing.
 */

import { apiKey, refreshInterval, setRefreshInterval, dashboardPollInterval } from '../core/state.js';

/** Parse location.hash into {tab, subTab}. */
export function parseHash() {
    const hash = location.hash.replace(/^#/, '');
    if (!hash) return {};
    const [tab, subTab] = hash.split('/');
    return { tab, subTab };
}

/** Update the URL hash without triggering popstate. */
function _setHash(tab, subTab) {
    const hash = '#' + (subTab ? `${tab}/${subTab}` : tab);
    history.replaceState(null, '', hash);
}

let _suppressHashUpdate = false;
let _activeTab = null;

const _tabScrollPositions = {};

export function switchTab(name, { updateHash = true, skipLoad = false } = {}) {
    if (_activeTab === name) return;
    // Save scroll position of the tab we're leaving
    if (_activeTab) _tabScrollPositions[_activeTab] = window.scrollY;
    _activeTab = name;

    document.querySelectorAll('.tab-btn').forEach(btn => {
        const isActive = btn.dataset.tab === name;
        btn.classList.toggle('active', isActive);
        btn.setAttribute('aria-selected', String(isActive));
    });
    document.querySelectorAll('.tab-panel').forEach(panel => panel.classList.toggle('active', panel.id === `tab-${name}`));
    localStorage.setItem('activeTab', name);

    // Restore scroll position for this tab
    requestAnimationFrame(() => window.scrollTo(0, _tabScrollPositions[name] || 0));

    if (updateHash && !_suppressHashUpdate) {
        const subTab = name === 'targets'
            ? (localStorage.getItem('activeTargetSubTab') || 'led')
            : name === 'streams'
            ? (localStorage.getItem('activeStreamTab') || 'raw')
            : null;
        _setHash(name, subTab);
    }

    if (name === 'dashboard') {
        // Use window.* to avoid circular imports with feature modules
        if (!skipLoad && apiKey && typeof window.loadDashboard === 'function') window.loadDashboard();
    } else {
        if (typeof window.stopPerfPolling === 'function') window.stopPerfPolling();
        if (typeof window.stopUptimeTimer === 'function') window.stopUptimeTimer();
        // Clean up WebSockets when leaving targets tab
        if (name !== 'targets') {
            if (typeof window.disconnectAllKCWebSockets === 'function') window.disconnectAllKCWebSockets();
            if (typeof window.disconnectAllLedPreviewWS === 'function') window.disconnectAllLedPreviewWS();
        }
        if (!apiKey || skipLoad) return;
        if (name === 'streams') {
            if (typeof window.loadPictureSources === 'function') window.loadPictureSources();
        } else if (name === 'targets') {
            if (typeof window.loadTargetsTab === 'function') window.loadTargetsTab();
        } else if (name === 'automations') {
            if (typeof window.loadAutomations === 'function') window.loadAutomations();
        }
    }
}

export function initTabs() {
    // Hash takes priority over localStorage
    const hashRoute = parseHash();
    let saved;

    if (hashRoute.tab && document.getElementById(`tab-${hashRoute.tab}`)) {
        saved = hashRoute.tab;
        // Pre-set sub-tab so the sub-tab switch functions pick it up
        if (hashRoute.subTab) {
            if (saved === 'targets') localStorage.setItem('activeTargetSubTab', hashRoute.subTab);
            if (saved === 'streams') localStorage.setItem('activeStreamTab', hashRoute.subTab);
        }
    } else {
        saved = localStorage.getItem('activeTab');
    }

    if (!saved || !document.getElementById(`tab-${saved}`)) saved = 'dashboard';
    switchTab(saved);
}

/** Update hash when sub-tab changes. Called from targets.js / streams.js. */
export function updateSubTabHash(tab, subTab) {
    _setHash(tab, subTab);
}

/** Update the count badge on a main tab button. Hidden when count is 0. */
export function updateTabBadge(tabName, count) {
    const badge = document.getElementById(`tab-badge-${tabName}`);
    if (!badge) return;
    if (count > 0) {
        badge.textContent = count;
        badge.style.display = '';
    } else {
        badge.style.display = 'none';
    }
}

export function startAutoRefresh() {
    if (refreshInterval) {
        clearInterval(refreshInterval);
    }

    setRefreshInterval(setInterval(() => {
        if (!apiKey || document.hidden) return;
        const activeTab = localStorage.getItem('activeTab') || 'dashboard';
        if (activeTab === 'targets') {
            // Skip refresh while user interacts with a picker or slider
            const panel = document.getElementById('targets-panel-content');
            if (panel && panel.contains(document.activeElement) && document.activeElement.matches('input')) return;
            if (typeof window.loadTargetsTab === 'function') window.loadTargetsTab();
        } else if (activeTab === 'dashboard') {
            if (typeof window.loadDashboard === 'function') window.loadDashboard();
        }
    }, dashboardPollInterval));
}

/**
 * Handle browser back/forward via popstate.
 * Called from app.js.
 */
export function handlePopState() {
    const hashRoute = parseHash();
    if (!hashRoute.tab) return;

    const currentTab = localStorage.getItem('activeTab');
    _suppressHashUpdate = true;

    if (hashRoute.tab !== currentTab) {
        switchTab(hashRoute.tab, { updateHash: false });
    }

    if (hashRoute.subTab) {
        if (hashRoute.tab === 'targets') {
            const currentSub = localStorage.getItem('activeTargetSubTab');
            if (hashRoute.subTab !== currentSub && typeof window.switchTargetSubTab === 'function') {
                window.switchTargetSubTab(hashRoute.subTab);
            }
        } else if (hashRoute.tab === 'streams') {
            const currentSub = localStorage.getItem('activeStreamTab');
            if (hashRoute.subTab !== currentSub && typeof window.switchStreamTab === 'function') {
                window.switchStreamTab(hashRoute.subTab);
            }
        }
    }

    _suppressHashUpdate = false;
}