/* Atlus — Core shell: app switching, WebSocket stats, panel updates */
(function () {
    'use strict';

    // =====================================================================
    // Auth guard
    // =====================================================================
    const TOKEN = localStorage.getItem('atlus_token');
    const USER = localStorage.getItem('atlus_user');
    if (!TOKEN) {
        window.location.href = '/';
        return;
    }

    // =====================================================================
    // Globals
    // =====================================================================
    window.Atlus = {
        token: TOKEN,
        user: USER,
        apps: {},          // registered app modules { id: { init, destroy, title } }
        openApps: [],      // ordered list of open app ids
        activeApp: null,   // currently focused app id
        layout: 'single',  // 'single' | 'split'
        secondaryApp: null,

        /** Authenticated fetch wrapper */
        async apiFetch(url, opts = {}) {
            opts.headers = Object.assign({ 'Authorization': `Bearer ${TOKEN}` }, opts.headers || {});
            if (opts.body && typeof opts.body === 'object' && !(opts.body instanceof FormData)) {
                opts.headers['Content-Type'] = 'application/json';
                opts.body = JSON.stringify(opts.body);
            }
            const res = await fetch(url, opts);
            if (res.status === 401) {
                localStorage.removeItem('atlus_token');
                localStorage.removeItem('atlus_user');
                window.location.href = '/';
                return;
            }
            return res;
        },

        /** Create an authenticated WebSocket URL */
        wsUrl(path) {
            const proto = location.protocol === 'https:' ? 'wss:' : 'ws:';
            const sep = path.includes('?') ? '&' : '?';
            return `${proto}//${location.host}${path}${sep}token=${TOKEN}`;
        },

        /** Register an app module */
        registerApp(id, module) {
            this.apps[id] = module;
        },

        /** Format bytes to human readable */
        formatBytes(bytes) {
            if (bytes === 0) return '0 B';
            const k = 1024;
            const sizes = ['B', 'KB', 'MB', 'GB', 'TB'];
            const i = Math.floor(Math.log(bytes) / Math.log(k));
            return parseFloat((bytes / Math.pow(k, i)).toFixed(1)) + ' ' + sizes[i];
        },
    };

    // =====================================================================
    // DOM refs
    // =====================================================================
    const $ = (sel) => document.querySelector(sel);
    const $$ = (sel) => document.querySelectorAll(sel);

    const stageTabs = $('#stageTabs');
    const paneA = $('#paneContentA');
    const paneB = $('#paneContentB');
    const paneTitleA = $('#paneTitleA');
    const paneTitleB = $('#paneTitleB');
    const paneBEl = $('#paneB');
    const welcomeScreen = $('#welcomeScreen');

    // =====================================================================
    // App switching
    // =====================================================================

    function openApp(appId) {
        const app = Atlus.apps[appId];
        if (!app) return;

        // Already open — just focus
        if (Atlus.openApps.includes(appId)) {
            focusApp(appId);
            return;
        }

        Atlus.openApps.push(appId);
        addTab(appId, app.title || appId);

        // Create app container
        const container = document.createElement('div');
        container.className = 'app-view';
        container.id = `app-${appId}`;
        container.style.display = 'none';
        paneA.appendChild(container);

        // Initialize app
        if (app.init) app.init(container);

        focusApp(appId);
        saveDesktopState();
    }

    function focusApp(appId) {
        if (welcomeScreen) welcomeScreen.style.display = 'none';

        // Hide all apps in pane A
        paneA.querySelectorAll('.app-view').forEach(el => el.style.display = 'none');

        // Show target
        const target = $(`#app-${appId}`);
        if (target) target.style.display = 'flex';

        // Update tabs
        stageTabs.querySelectorAll('.stage-tab').forEach(tab => {
            tab.classList.toggle('active', tab.dataset.app === appId);
        });

        // Update dock
        $$('.dock-item[data-app]').forEach(item => {
            item.classList.toggle('active', item.dataset.app === appId);
        });

        // Update titlebar
        const app = Atlus.apps[appId];
        paneTitleA.textContent = app ? app.title : appId;

        Atlus.activeApp = appId;

        // Notify app it got focus
        if (app && app.onFocus) app.onFocus();

        saveDesktopState();
    }

    function closeApp(appId) {
        const app = Atlus.apps[appId];
        if (app && app.destroy) app.destroy();

        // Remove DOM
        const container = $(`#app-${appId}`);
        if (container) container.remove();

        // Remove from open list
        Atlus.openApps = Atlus.openApps.filter(id => id !== appId);

        // Remove tab
        const tab = stageTabs.querySelector(`.stage-tab[data-app="${appId}"]`);
        if (tab) tab.remove();

        // Update dock
        const dockItem = $(`.dock-item[data-app="${appId}"]`);
        if (dockItem) dockItem.classList.remove('active');

        // Focus next app or show welcome
        if (Atlus.activeApp === appId) {
            if (Atlus.openApps.length > 0) {
                focusApp(Atlus.openApps[Atlus.openApps.length - 1]);
            } else {
                Atlus.activeApp = null;
                paneTitleA.textContent = '';
                if (welcomeScreen) welcomeScreen.style.display = 'flex';
            }
        }
        saveDesktopState();
    }

    function addTab(appId, title) {
        const tab = document.createElement('button');
        tab.className = 'stage-tab';
        tab.dataset.app = appId;
        tab.innerHTML = `<span>${title}</span><span class="tab-close">&times;</span>`;
        tab.addEventListener('click', (e) => {
            if (e.target.classList.contains('tab-close')) {
                closeApp(appId);
            } else {
                focusApp(appId);
            }
        });
        stageTabs.appendChild(tab);
    }

    // =====================================================================
    // Dock clicks
    // =====================================================================
    $$('.dock-item[data-app]').forEach(item => {
        item.addEventListener('click', () => openApp(item.dataset.app));
    });

    // Layout toggle
    $$('.layout-btn').forEach(btn => {
        btn.addEventListener('click', () => {
            const layout = btn.dataset.layout;
            Atlus.layout = layout;
            $$('.layout-btn').forEach(b => b.classList.toggle('active', b.dataset.layout === layout));
            paneBEl.classList.toggle('hidden', layout === 'single');
        });
    });

    // =====================================================================
    // System menu
    // =====================================================================
    const systemMenu = $('#systemMenu');
    const logoBtn = $('.dock-logo');

    logoBtn.addEventListener('click', () => {
        systemMenu.classList.toggle('hidden');
    });

    systemMenu.addEventListener('click', async (e) => {
        const action = e.target.dataset.action;
        if (!action) {
            // Clicked backdrop
            if (e.target === systemMenu) systemMenu.classList.add('hidden');
            return;
        }
        systemMenu.classList.add('hidden');

        if (action === 'logout') {
            await Atlus.apiFetch('/api/auth/logout', { method: 'POST' });
            localStorage.removeItem('atlus_token');
            localStorage.removeItem('atlus_user');
            window.location.href = '/';
        }
    });

    // =====================================================================
    // Panel — Clock
    // =====================================================================
    function updateClock() {
        const now = new Date();
        $('#panelDate').textContent = now.toLocaleDateString('en-US', {
            weekday: 'short', month: 'short', day: 'numeric'
        });
        $('#panelTime').textContent = now.toLocaleTimeString('en-US', {
            hour: '2-digit', minute: '2-digit', hour12: false
        });
    }
    updateClock();
    setInterval(updateClock, 1000);

    // =====================================================================
    // Panel — WebSocket stats
    // =====================================================================
    let statsWs = null;

    function connectStats() {
        statsWs = new WebSocket(Atlus.wsUrl('/api/stats/ws'));

        statsWs.onmessage = (e) => {
            const data = JSON.parse(e.data);
            updatePanel(data);
        };

        statsWs.onclose = () => {
            setTimeout(connectStats, 3000);
        };

        statsWs.onerror = () => {
            statsWs.close();
        };
    }

    function updatePanel(data) {
        // CPU
        const cpuPct = Math.round(data.cpu_percent);
        $('#statCpu').textContent = cpuPct + '%';
        updateBar($('#statCpuBar'), cpuPct);

        // Memory
        const memPct = Math.round(data.memory.percent);
        const memUsed = Atlus.formatBytes(data.memory.used);
        const memTotal = Atlus.formatBytes(data.memory.total);
        $('#statMem').textContent = `${memUsed} / ${memTotal}`;
        updateBar($('#statMemBar'), memPct);

        // Disk
        const diskPct = Math.round(data.disk.percent);
        $('#statDisk').textContent = diskPct + '%';
        updateBar($('#statDiskBar'), diskPct);

        // Temp
        if (data.cpu_temp !== null) {
            const temp = Math.round(data.cpu_temp);
            $('#statTemp').textContent = temp + '\u00B0C';
            // Temp bar: 0-85°C range
            const tempPct = Math.min(100, Math.round((temp / 85) * 100));
            updateBar($('#statTempBar'), tempPct);
        }

        // Network
        const netContainer = $('#panelNetwork');
        netContainer.innerHTML = '';
        const ifaces = data.network.interfaces;
        for (const [name, info] of Object.entries(ifaces)) {
            const item = document.createElement('div');
            item.className = 'panel-net-item';
            item.innerHTML = `
                <span class="panel-net-dot ${info.up ? 'up' : 'down'}"></span>
                <span class="panel-net-name">${name}</span>
                <span class="panel-net-ip">${info.ipv4 || '--'}</span>
            `;
            netContainer.appendChild(item);
        }
    }

    function updateBar(barEl, percent) {
        barEl.style.width = percent + '%';
        barEl.className = 'stat-bar-fill';
        if (percent >= 90) barEl.classList.add('crit');
        else if (percent >= 70) barEl.classList.add('warn');
    }

    // =====================================================================
    // Panel — Hostname
    // =====================================================================
    async function loadHostname() {
        try {
            const res = await Atlus.apiFetch('/api/settings/system');
            if (res.ok) {
                const data = await res.json();
                $('#panelHostname').textContent = data.hostname;
            }
        } catch (e) { /* ignore */ }
    }

    // =====================================================================
    // Panel — Applications (docked GUI apps)
    // =====================================================================
    async function loadPanelApps() {
        const container = $('#panelApps');
        if (!container) return;

        let guiApps = [];
        let runningApps = [];

        try {
            const cfgRes = await Atlus.apiFetch('/api/settings');
            if (cfgRes && cfgRes.ok) {
                const cfg = await cfgRes.json();
                guiApps = cfg.gui_apps || [];
            }
        } catch (e) {
            console.warn('Panel apps: failed to load config', e);
        }

        try {
            const runRes = await Atlus.apiFetch('/api/display/apps');
            if (runRes && runRes.ok) runningApps = await runRes.json();
        } catch (e) { /* display may be unavailable */ }

        // Ensure all GUI apps are registered as Atlus app modules
        for (const app of guiApps) {
            try {
                const appId = 'gui-' + app.id;
                if (!Atlus.apps[appId] && window._atlusRegisterGuiApp) {
                    window._atlusRegisterGuiApp(app);
                }
            } catch (e) {
                console.warn('Panel apps: failed to register', app.id, e);
            }
        }

        // Clear and rebuild — always append Add button at the end
        container.innerHTML = '';

        if (guiApps.length === 0) {
            const empty = document.createElement('div');
            empty.style.cssText = 'color:var(--text-muted);font-size:12px;font-family:var(--font-mono);padding:4px 0;';
            empty.textContent = 'No apps configured';
            container.appendChild(empty);
        } else {
            for (const app of guiApps) {
                try {
                    const running = Array.isArray(runningApps)
                        ? runningApps.find(r => r.command === app.command && r.alive)
                        : null;
                    const row = document.createElement('div');
                    row.className = 'panel-app-row';

                    const args = Array.isArray(app.args) ? app.args.join(' ') : '';
                    row.innerHTML = `
                        <div class="panel-app-dot ${running ? 'active' : ''}"></div>
                        <span class="panel-app-icon">${app.icon || '🖥'}</span>
                        <span class="panel-app-name">${app.name || app.command}</span>
                        <button class="panel-app-action ${running ? 'stop' : 'start'}"
                                data-command="${app.command}" data-app-id="${running ? running.app_id : ''}"
                                data-gui-id="${app.id}" data-title="${app.name || app.command}"
                                data-args="${args}" data-fps="${app.target_fps || 10}"
                                title="${running ? 'Stop' : 'Launch'}">
                            ${running ? '■' : '▶'}
                        </button>
                    `;

                    // Click name/icon to open in tab
                    row.querySelector('.panel-app-name').addEventListener('click', () => {
                        openApp('gui-' + app.id);
                    });
                    row.querySelector('.panel-app-icon').addEventListener('click', () => {
                        openApp('gui-' + app.id);
                    });

                    // Action button (launch/stop)
                    const actionBtn = row.querySelector('.panel-app-action');
                    actionBtn.addEventListener('click', async (e) => {
                        e.stopPropagation();
                        const isRunning = actionBtn.classList.contains('stop');
                        actionBtn.disabled = true;

                        try {
                            if (isRunning) {
                                const id = actionBtn.dataset.appId;
                                if (id) await Atlus.apiFetch(`/api/display/apps/${id}`, { method: 'DELETE' });
                            } else {
                                const a = actionBtn.dataset.args ? actionBtn.dataset.args.split(' ').filter(Boolean) : [];
                                await Atlus.apiFetch('/api/display/apps', {
                                    method: 'POST',
                                    body: {
                                        command: actionBtn.dataset.command,
                                        title: actionBtn.dataset.title,
                                        args: a,
                                        target_fps: parseInt(actionBtn.dataset.fps) || 10,
                                    },
                                });
                            }
                        } catch (err) {
                            console.warn('Panel app action failed', err);
                        }
                        setTimeout(loadPanelApps, 1500);
                    });

                    container.appendChild(row);
                } catch (e) {
                    console.warn('Panel apps: failed to render', app.id, e);
                }
            }
        }

        // Add App button — ALWAYS appended, regardless of errors above
        const addBtn = document.createElement('button');
        addBtn.className = 'panel-app-add';
        addBtn.textContent = '+ Add';
        addBtn.addEventListener('click', () => {
            openApp('settings');
            setTimeout(() => {
                const navItem = document.querySelector('.settings-nav-item[data-section="applications"]');
                if (navItem) navItem.click();
            }, 200);
        });
        container.appendChild(addBtn);
    }

    // =====================================================================
    // Panel — Update checker
    // =====================================================================

    async function checkForUpdates() {
        const panel = $('#panelUpdates');
        if (!panel) return;
        try {
            const res = await Atlus.apiFetch('/api/updates/check');
            if (!res || !res.ok) {
                // Show error state if endpoint fails (503 = git not found, etc.)
                panel.classList.remove('hidden');
                const status = res ? res.status : 0;
                const detail = res ? await res.json().catch(() => ({})) : {};
                panel.innerHTML = `
                    <div class="update-status">
                        <span class="update-status-dot" style="background:var(--text-muted);"></span>
                        <div class="update-status-text">
                            <div class="update-status-title">Updates unavailable</div>
                            <div class="update-status-hash">${detail.detail || 'Could not check'}</div>
                        </div>
                    </div>
                `;
                return;
            }
            const data = await res.json();

            panel.classList.remove('hidden');

            if (data.error) {
                showUpdateError(panel, data);
            } else if (data.available && data.behind_count > 0) {
                showUpdateAvailable(panel, data);
            } else {
                showUpToDate(panel, data);
            }
        } catch (e) {
            console.warn('Update check failed:', e);
        }
    }

    function showUpToDate(panel, data) {
        panel.innerHTML = `
            <div class="update-status update-current">
                <span class="update-status-dot current"></span>
                <div class="update-status-text">
                    <div class="update-status-title">Up to date</div>
                    <div class="update-status-hash">${data.local_hash}</div>
                </div>
            </div>
        `;
    }

    function showUpdateError(panel, data) {
        panel.innerHTML = `
            <div class="update-status">
                <span class="update-status-dot" style="background:var(--status-red);"></span>
                <div class="update-status-text">
                    <div class="update-status-title">Check failed</div>
                    <div class="update-status-hash">${data.error}</div>
                </div>
            </div>
        `;
    }

    function showUpdateAvailable(panel, data) {
        const pkgs = data.new_packages || [];
        const hasPkgs = pkgs.length > 0;

        let pkgHtml = '';
        if (hasPkgs) {
            pkgHtml = `
                <div class="update-packages">
                    <div class="update-packages-title">New system packages needed:</div>
                    <div class="update-packages-list">${pkgs.join(', ')}</div>
                    <label class="update-packages-toggle">
                        <input type="checkbox" class="update-install-pkgs-cb" checked>
                        <span>Install packages with update</span>
                    </label>
                </div>
            `;
        }

        panel.innerHTML = `
            <div class="update-status update-available">
                <span class="update-status-dot available"></span>
                <div class="update-status-text">
                    <div class="update-status-title">Update available</div>
                    <div class="update-status-hash">${data.behind_count} commit${data.behind_count !== 1 ? 's' : ''} behind (${data.remote_hash})</div>
                </div>
                <button class="update-install-btn" title="Install update">Update</button>
            </div>
            ${pkgHtml}
        `;

        panel.querySelector('.update-install-btn').addEventListener('click', async (e) => {
            const btn = e.target;
            btn.disabled = true;

            const installPkgs = hasPkgs && panel.querySelector('.update-install-pkgs-cb')?.checked;

            // Step 1: Install system packages if needed
            if (installPkgs) {
                btn.textContent = 'Installing packages…';
                try {
                    const depRes = await Atlus.apiFetch('/api/updates/install-deps', {
                        method: 'POST',
                        body: { packages: pkgs },
                    });
                    if (!depRes.ok) {
                        const err = await depRes.json().catch(() => ({}));
                        btn.textContent = 'Pkg install failed';
                        btn.disabled = false;
                        console.error('Package install failed:', err);
                        return;
                    }
                } catch (err) {
                    btn.textContent = 'Pkg install failed';
                    btn.disabled = false;
                    console.error('Package install error:', err);
                    return;
                }
            }

            // Step 2: Apply the update (git pull + pip + restart)
            btn.textContent = 'Updating…';
            try {
                const res = await Atlus.apiFetch('/api/updates/apply', { method: 'POST' });
                if (res.ok) {
                    btn.textContent = 'Restarting…';
                    setTimeout(() => attemptReload(0), 4000);
                } else {
                    btn.textContent = 'Failed';
                    btn.disabled = false;
                }
            } catch (e) {
                // Connection lost = server restarting
                btn.textContent = 'Restarting…';
                setTimeout(() => attemptReload(0), 4000);
            }
        });
    }

    function attemptReload(attempt) {
        if (attempt > 10) return; // Give up after ~30s
        fetch('/desktop', { method: 'HEAD' })
            .then(() => window.location.reload())
            .catch(() => setTimeout(() => attemptReload(attempt + 1), 3000));
    }

    // =====================================================================
    // Session persistence — save/restore desktop state
    // =====================================================================
    let _saveTimer = null;

    function saveDesktopState() {
        // Debounce — save at most once per second
        if (_saveTimer) clearTimeout(_saveTimer);
        _saveTimer = setTimeout(_doSaveState, 1000);
    }

    function _doSaveState() {
        const termApp = Atlus.apps.terminal;
        const terminalTabs = (termApp && termApp.getTerminalIds)
            ? termApp.getTerminalIds()
            : [];

        const state = {
            open_apps: Atlus.openApps.slice(),
            active_app: Atlus.activeApp,
            terminal_tabs: terminalTabs,
        };

        Atlus.apiFetch('/api/session/state', {
            method: 'PUT',
            body: state,
        }).catch(() => {}); // best-effort
    }

    async function restoreSession() {
        try {
            const res = await Atlus.apiFetch('/api/session');
            if (!res || !res.ok) return;
            const session = await res.json();
            const state = session.desktop_state || {};
            const openApps = state.open_apps || [];
            const activeApp = state.active_app;
            const serverTerminals = session.terminals || {};

            // Store terminal info for the terminal app to use when it inits
            Atlus._restoredTerminals = Object.values(serverTerminals);
            Atlus._restoredTerminalTabs = state.terminal_tabs || [];

            // Re-open apps in saved order
            for (const appId of openApps) {
                if (Atlus.apps[appId]) {
                    openApp(appId);
                }
            }

            // Focus the previously active app
            if (activeApp && Atlus.openApps.includes(activeApp)) {
                focusApp(activeApp);
            }
        } catch (e) {
            // First visit or server error — no session to restore
        }
    }

    // Save state on visibility change (tab switch / minimize)
    document.addEventListener('visibilitychange', () => {
        if (document.visibilityState === 'hidden') {
            _doSaveState(); // immediate save on hide
        }
    });

    // Save state before unload (use sendBeacon for reliability)
    window.addEventListener('beforeunload', () => {
        const termApp = Atlus.apps.terminal;
        const terminalTabs = (termApp && termApp.getTerminalIds)
            ? termApp.getTerminalIds() : [];
        const state = {
            open_apps: Atlus.openApps.slice(),
            active_app: Atlus.activeApp,
            terminal_tabs: terminalTabs,
        };
        const blob = new Blob([JSON.stringify(state)], { type: 'application/json' });
        navigator.sendBeacon('/api/session/state?token=' + TOKEN, blob);
    });

    // =====================================================================
    // Init
    // =====================================================================
    loadHostname();
    loadPanelApps();
    connectStats();

    // Refresh applications panel periodically
    setInterval(loadPanelApps, 30000);

    // Update scanner — read interval and enabled state from config
    (async function initUpdateChecker() {
        try {
            const cfgRes = await Atlus.apiFetch('/api/settings');
            if (cfgRes.ok) {
                const cfg = await cfgRes.json();
                const enabled = cfg.update_check_enabled !== false;
                const intervalSec = cfg.update_check_interval || 60;
                if (enabled) {
                    checkForUpdates();
                    setInterval(checkForUpdates, intervalSec * 1000);
                }
            } else {
                // Fallback: check every 60s
                checkForUpdates();
                setInterval(checkForUpdates, 60 * 1000);
            }
        } catch (e) {
            checkForUpdates();
            setInterval(checkForUpdates, 60 * 1000);
        }
    })();

    // Expose for app modules
    window.Atlus.openApp = openApp;
    window.Atlus.closeApp = closeApp;
    window.Atlus.focusApp = focusApp;
    window.Atlus.saveDesktopState = saveDesktopState;
    window._atlusLoadPanelApps = loadPanelApps;

    // Restore previous session (after a brief delay to let app modules register)
    setTimeout(restoreSession, 100);
})();