// ==========================================
// Chat Switchboard – Application
// ==========================================
// State, init, boot, auth, listener dispatch.
// Domain logic lives in chat.js, notes.js, settings-handlers.js,
// admin-handlers.js. UI rendering in ui-*.js files.

const App = {
    chats: [],
    currentChatId: null,
    models: [],
    hiddenModels: new Set(),
    isGenerating: false,
    abortController: null,
    serverSettings: {},
    policies: {},
    stagedAttachments: [],
    channelAttachments: {},   // messageId → [attachment, ...] — populated on chat load
    storageConfigured: false,
    projects: [],              // v0.19.0: loaded from /api/v1/projects
    collapsedProjects: {},     // projectId → bool — sidebar collapse state
    activeProjectId: null,     // v0.19.1: new chats auto-assign to this project
    showArchivedProjects: false, // v0.19.2: toggle archived projects in sidebar

    // Find model by composite ID, with fallback to bare model_id match
    findModel(id) {
        if (!id) return null;
        // Exact match on composite ID (configId:modelId)
        let m = App.models.find(m => m.id === id);
        if (m) return m;
        // Fallback: bare model_id (backward compat with stored settings)
        return App.models.find(m => m.baseModelId === id) || null;
    },

    settings: {
        model: '',
        stream: true,
        showThinking: false,
        systemPrompt: '',
        maxTokens: 0,  // 0 = auto from model capabilities
        temperature: 0.7,
    },
};

// ── Models ───────────────────────────────────

// ── Capability Resolution ───────────────────────────────────────
// The backend is the source of truth for model capabilities.
// Resolution chain on the server: catalog (provider API sync) → heuristic.
// The frontend does NOT maintain a static model table — the same model
// can have different capabilities on different providers (e.g. DeepSeek
// on Venice has no tool_calling, same model on OpenRouter does).

// resolveCapabilities returns backend caps as-is. No client-side override.
function resolveCapabilities(backendCaps, modelId) {
    return backendCaps && Object.keys(backendCaps).length > 0 ? { ...backendCaps } : {};
}

async function fetchModels() {
    try {
        const data = await API.listEnabledModels();
        App.defaultModel = data.default_model || '';
        // Load user model preferences
        try {
            const prefData = await API.getModelPreferences();
            App.hiddenModels = new Set(
                (prefData.preferences || []).filter(p => p.hidden).map(p => p.model_id)
            );
        } catch (e) {
            // Keep existing preferences on failure (auth dead, network issue).
            // Only init to empty if there's nothing to preserve.
            if (!App.hiddenModels) App.hiddenModels = new Set();
        }

        App.models = (data.models || []).map(m => {
            const isPreset = !!m.is_preset;
            const baseModelId = m.model_id || m.id;
            // Presets use preset_id; base models use configId:modelId to avoid
            // collisions when the same model exists across team/personal/global providers
            const id = isPreset
                ? (m.preset_id || m.id)
                : ((m.config_id || m.provider_config_id) ? `${m.config_id || m.provider_config_id}:${baseModelId}` : baseModelId);
            return {
                id,
                baseModelId,
                name: m.display_name || baseModelId,
                provider: m.provider_name || m.provider || '',
                configId: m.config_id || m.provider_config_id || null,
                model_type: m.model_type || 'chat',
                capabilities: resolveCapabilities(m.capabilities, baseModelId),
                isPreset,
                presetId: m.preset_id || m.persona_id || null,
                presetScope: m.preset_scope || (isPreset ? m.scope : null) || null,
                presetAvatar: m.preset_avatar || (isPreset ? m.avatar : null) || null,
                presetTeamName: m.preset_team_name || (isPreset ? m.team_name : null) || null,
                source: m.source || (isPreset ? 'preset' : 'global'),
                teamName: m.preset_team_name || null,
                hidden: !isPreset && App.hiddenModels.has(baseModelId),
            };
        });

        // Sort: presets first (global > team > personal), then regular models
        const scopeOrder = { global: 0, team: 1, personal: 2 };
        App.models.sort((a, b) => {
            if (a.isPreset && !b.isPreset) return -1;
            if (!a.isPreset && b.isPreset) return 1;
            if (a.isPreset && b.isPreset) {
                const sa = scopeOrder[a.presetScope] ?? 9;
                const sb = scopeOrder[b.presetScope] ?? 9;
                if (sa !== sb) return sa - sb;
            }
            return a.name.localeCompare(b.name);
        });
        console.log(`📋 Loaded ${App.models.length} models (${App.models.filter(m => m.isPreset).length} presets, ${App.models.filter(m => m.hidden).length} hidden)`);
    } catch (e) { console.warn('Model fetch failed:', e.message); }

    UI.updateModelSelector();
    UI.updateCapabilityBadges();
}

async function init() {
    console.log('🔀 Chat Switchboard initializing...');
    initBranding();  // Apply branding before splash is visible
    API.loadTokens();

    let health = null;
    try {
        health = await API.health();
        console.log('✅ Backend reachable:', health.version);
    } catch (e) {
        console.error('❌ Backend unreachable:', e.message);
        const splashErr = document.getElementById('splashError');
        if (e.proxyBlocked) {
            splashErr.innerHTML =
                `<strong>Network proxy blocked this request</strong><br>` +
                `Proxy response: "${API._esc(e.proxyTitle)}"<br>` +
                `<span class="splash-error-hint">Ask your network admin to whitelist this domain. ` +
                `<a href="#" onclick="openDebugModal();return false">Run diagnostics</a></span>`;
        } else if (e.name === 'TimeoutError' || e.name === 'AbortError') {
            splashErr.innerHTML =
                `<strong>Connection timed out</strong><br>` +
                `<span class="splash-error-hint">Server may be starting up, or a proxy is blocking the connection. ` +
                `<a href="#" onclick="openDebugModal();return false">Run diagnostics</a></span>`;
        } else {
            splashErr.innerHTML =
                `<strong>Cannot reach server</strong><br>` +
                `<span class="splash-error-hint">${API._esc(e.message)}. ` +
                `<a href="#" onclick="openDebugModal();return false">Run diagnostics</a></span>`;
        }
        showSplash(null);
        return;
    }

    if (API.isAuthed) {
        try {
            await API.getProfile();
            console.log('✅ Session valid for', API.user?.username);
        } catch (e) {
            console.warn('⚠️ Session expired, clearing');
            API.clearTokens();
        }
    }

    if (API.isAuthed) {
        await startApp();
    } else {
        showSplash(health);
    }
}

async function startApp() {
    hideSplash();
    UI.restoreSidebar();
    await loadSettings();

    // Load extensions BEFORE chats so block renderers (mermaid, katex, csv, diff)
    // are registered when messages are first rendered.
    try {
        await Extensions.loadAll();   // fetch manifests + inject <script> tags
        await Extensions.initAll();   // build ctx, call init(), set up tool bridge
    } catch (e) {
        console.warn('Extension init error:', e.message);
    }

    await loadChats();
    await loadProjects();
    await loadProjectChannelPositions(); // v0.19.2: load channel order per project
    await fetchModels();

    // Guard: if token was invalidated during startup (401 → refresh fail → clearTokens),
    // kick back to login instead of rendering a broken UI.
    if (!API.isAuthed) {
        console.warn('⚠️ Auth lost during startup, returning to login');
        showSplash(null);
        return;
    }

    await initBanners();
    initAttachments();
    if (typeof ToolsToggle !== 'undefined') ToolsToggle.init();
    if (typeof KnowledgeUI !== 'undefined') {
        KnowledgeUI.init();
    } else {
        console.error('[App] KnowledgeUI module not defined — knowledge-ui.js failed to load or parse');
    }
    UI.renderChatList();
    UI.updateModelSelector();

    // Restore last-active chat from sessionStorage (QOL: state restore on refresh)
    try {
        const savedChat = sessionStorage.getItem('cs-active-chat');
        if (savedChat && App.chats.some(c => c.id === savedChat)) {
            selectChat(savedChat);
        }
    } catch (_) {}

    UI.updateUser();
    UI.showAdminButton(API.isAdmin);
    initListeners();

    // Connect EventBus WebSocket (non-blocking, graceful if /ws not available yet)
    try {
        Events.connect((window.__BASE__ || '') + '/ws');

        // Admin-only: persistent fallback alert banner (v0.17.0)
        Events.on('role.fallback', (payload) => {
            if (App.user?.role !== 'admin') return;
            const data = typeof payload === 'string' ? JSON.parse(payload) : payload;
            showFallbackBanner(data);
        });
    } catch (e) {
        console.warn('EventBus WebSocket not available:', e.message);
    }

    console.log('✅ Chat Switchboard ready');
}

// ── Role Fallback Banner (v0.17.0) ──────────

function showFallbackBanner(data) {
    let banner = document.getElementById('roleFallbackBanner');
    if (!banner) {
        // Create persistent banner above messages
        banner = document.createElement('div');
        banner.id = 'roleFallbackBanner';
        banner.className = 'role-fallback-banner';
        const msgs = document.getElementById('chatMessages');
        if (msgs) msgs.parentNode.insertBefore(banner, msgs);
        else return;
    }
    const msg = data.message || `Role "${data.role}" primary failed — using fallback`;
    banner.innerHTML = `
        <span class="fallback-icon">⚠️</span>
        <span class="fallback-msg">${esc(msg)}</span>
        <button class="btn-small" onclick="this.parentElement.remove()">Dismiss</button>`;
    banner.style.display = '';
}

// ── Modal Helpers ───────────────────────────

function openModal(id) {
    const el = document.getElementById(id);
    if (!el) return;
    el.classList.add('active');
    // Defer overflow check — browser needs a frame to lay out the modal
    requestAnimationFrame(() => {
        el.querySelectorAll('.modal-tabs').forEach(checkTabsOverflow);
    });
}

function closeModal(id) {
    const el = document.getElementById(id);
    if (el) el.classList.remove('active');
}

// Toggle .is-scrollable on tab bars that overflow horizontally
// and inject arrow navigation buttons when needed.
function checkTabsOverflow(tabs) {
    if (!tabs) return;
    const scrollable = tabs.scrollWidth > tabs.clientWidth + 1;

    if (!scrollable) {
        // Remove wrapper if overflow went away (e.g. zoom decreased)
        const wrap = tabs.parentElement;
        if (wrap && wrap.classList.contains('modal-tabs-wrap')) {
            wrap.parentElement.insertBefore(tabs, wrap);
            wrap.remove();
        }
        return;
    }

    // Wrap if not already wrapped
    if (!tabs.parentElement.classList.contains('modal-tabs-wrap')) {
        const wrap = document.createElement('div');
        wrap.className = 'modal-tabs-wrap';
        tabs.parentElement.insertBefore(wrap, tabs);
        wrap.appendChild(tabs);

        // Inject arrows
        const left = document.createElement('button');
        left.className = 'tab-arrow tab-arrow-left';
        left.innerHTML = '&#x2039;';
        left.addEventListener('click', () => { tabs.scrollLeft -= 120; });

        const right = document.createElement('button');
        right.className = 'tab-arrow tab-arrow-right';
        right.innerHTML = '&#x203A;';
        right.addEventListener('click', () => { tabs.scrollLeft += 120; });

        wrap.appendChild(left);
        wrap.appendChild(right);

        // Update arrow visibility on scroll
        tabs.addEventListener('scroll', () => updateTabArrows(tabs), { passive: true });
    }

    updateTabArrows(tabs);
}

function updateTabArrows(tabs) {
    const wrap = tabs.parentElement;
    if (!wrap || !wrap.classList.contains('modal-tabs-wrap')) return;

    const left = wrap.querySelector('.tab-arrow-left');
    const right = wrap.querySelector('.tab-arrow-right');
    if (!left || !right) return;

    const atStart = tabs.scrollLeft <= 2;
    const atEnd = tabs.scrollLeft + tabs.clientWidth >= tabs.scrollWidth - 2;

    left.classList.toggle('visible', !atStart);
    right.classList.toggle('visible', !atEnd);
}

// ── Auth Flow ────────────────────────────────

function showSplash(health) {
    document.getElementById('splashGate').style.display = 'flex';
    document.getElementById('appContainer').style.display = 'none';
    if (health && health.registration_enabled === false) {
        document.getElementById('authTabRegister').style.display = 'none';
    }
}

function hideSplash() {
    document.getElementById('splashGate').style.display = 'none';
    document.getElementById('appContainer').style.display = '';
}

async function handleLogin() {
    const login = document.getElementById('authLogin').value.trim();
    const password = document.getElementById('authPassword').value;
    if (!login || !password) return setAuthError('Fill in all fields');
    setAuthLoading(true);
    try { await API.login(login, password); await startApp(); }
    catch (e) { setAuthError(e.message); }
    finally { setAuthLoading(false); }
}

async function handleRegister() {
    const username = document.getElementById('authUsername').value.trim();
    const email = document.getElementById('authEmail').value.trim();
    const password = document.getElementById('authRegPassword').value;
    if (!username || !email || !password) return setAuthError('Fill in all fields');
    if (password.length < 8) return setAuthError('Password must be at least 8 characters');
    setAuthLoading(true);
    try {
        const resp = await API.register(username, email, password);
        if (resp.pending) {
            setAuthError('');
            const errEl = document.getElementById('authError');
            errEl.textContent = 'Account created — pending admin approval. You will be able to sign in once approved.';
            errEl.style.color = 'var(--accent)';
            setTimeout(() => { errEl.style.color = ''; switchAuthTab('login'); }, 5000);
        } else {
            await startApp();
        }
    }
    catch (e) { setAuthError(e.message); }
    finally { setAuthLoading(false); }
}

async function handleLogout() {
    if (!await showConfirm('Sign out?')) return;
    Events.disconnect();
    Events.clear();
    await API.logout();
    App.chats = [];
    App.currentChatId = null;
    location.reload();
}

function switchAuthTab(tab) {
    document.getElementById('authTabLogin').classList.toggle('active', tab === 'login');
    document.getElementById('authTabRegister').classList.toggle('active', tab === 'register');
    document.getElementById('authLoginForm').style.display = tab === 'login' ? '' : 'none';
    document.getElementById('authRegisterForm').style.display = tab === 'register' ? '' : 'none';
    document.getElementById('authLoginBtn').style.display = tab === 'login' ? '' : 'none';
    document.getElementById('authRegisterBtn').style.display = tab === 'register' ? '' : 'none';
    const hdr = document.querySelector('.auth-card-header');
    if (hdr) {
        hdr.querySelector('h2').textContent = tab === 'login' ? 'Welcome back' : 'Create account';
        hdr.querySelector('p').textContent = tab === 'login'
            ? 'Sign in to continue to your workspace'
            : 'Get started with Chat Switchboard';
    }
    setAuthError('');
}

function setAuthError(msg) { document.getElementById('authError').textContent = msg; }
function setAuthLoading(on) {
    document.querySelectorAll('#authLoginBtn, #authRegisterBtn').forEach(btn => {
        btn.disabled = on;
        btn.textContent = on ? 'Please wait...' : btn.dataset.label;
    });
}

// ── Event Listeners ─────────────────────────
// Thin dispatcher — domain listeners extracted to their own files.

let _listenersInit = false;
function initListeners() {
    if (_listenersInit) return;
    _listenersInit = true;

    _initChatListeners();       // from chat.js
    _initSettingsListeners();   // from settings-handlers.js
    _initAdminListeners();      // from admin-handlers.js
    _initNotesListeners();      // from notes.js
    _initAttachmentListeners(); // from attachments.js
    _registerPreviewPanel();    // from ui-format.js — register preview with PanelRegistry
    _registerNotesPanel();      // from notes.js — register notes with PanelRegistry
    _registerProjectPanel();    // from projects-ui.js — register project detail panel
    if (typeof Notifications !== 'undefined') Notifications.init(); // v0.20.0
    _initGlobalKeyboard();      // local: Escape, Ctrl+K, Ctrl+\, resize
    _initSidePanelResize();     // from panels.js
    _initDualDivider();         // from panels.js — dual-view split drag
    _initPanelSwipe();          // from panels.js — mobile swipe navigation
    _initPanelResponsive();     // from panels.js — auto-collapse dual on resize
    _initPanelOverlay();        // from panels.js — mobile tap-to-close overlay
}

function _initGlobalKeyboard() {
    // Keyboard shortcuts
    document.addEventListener('keydown', (e) => {
        // Escape: stop generation → close command palette → close side panel → close topmost modal
        if (e.key === 'Escape') {
            if (App.isGenerating) { stopGeneration(); return; }
            if (document.getElementById('lightbox')?.classList.contains('active')) {
                closeLightbox(); return;
            }
            if (document.getElementById('cmdPalette')?.classList.contains('active')) {
                closeCmdPalette(); return;
            }
            if (PanelRegistry.isContainerOpen()) {
                PanelRegistry.closeAll(); return;
            }
            const open = [...document.querySelectorAll('.modal-overlay.active')];
            if (open.length) closeModal(open[open.length - 1].id);
            return;
        }

        // Ctrl/Cmd+K: command palette
        if ((e.ctrlKey || e.metaKey) && e.key === 'k') {
            e.preventDefault();
            toggleCmdPalette();
            return;
        }

        // Ctrl/Cmd+\: cycle side panels
        if ((e.ctrlKey || e.metaKey) && !e.shiftKey && e.key === '\\') {
            e.preventDefault();
            PanelRegistry.cycle();
            return;
        }

        // Ctrl/Cmd+Shift+\: toggle dual-view split
        if ((e.ctrlKey || e.metaKey) && e.shiftKey && e.key === '\\') {
            e.preventDefault();
            PanelRegistry.toggleDual();
            return;
        }

        // Ctrl/Cmd+Shift+S: focus sidebar search
        if ((e.ctrlKey || e.metaKey) && e.shiftKey && e.key === 'S') {
            e.preventDefault();
            const sb = document.getElementById('sidebar');
            if (sb.classList.contains('collapsed')) UI.toggleSidebar();
            document.getElementById('chatSearchInput')?.focus();
            return;
        }
    });

    // Recheck tab overflow on resize / zoom changes
    window.addEventListener('resize', () => {
        document.querySelectorAll('.modal-overlay.active .modal-tabs').forEach(checkTabsOverflow);
    });
}

// ── Branding ────────────────────────────────

function initBranding() {
    const b = window.__BRANDING__;
    if (!b || typeof b !== 'object') return;

    const brandBase = (window.__BASE__ || '') + '/branding/';

    // Accent color → CSS custom property
    if (b.accent_color) {
        document.documentElement.style.setProperty('--accent-color', b.accent_color);
    }

    // Page title
    if (b.org_name) {
        document.title = b.org_name;
    }

    // Sidebar brand text
    const sidebarText = document.getElementById('brandSidebarText');
    if (sidebarText && b.org_name) sidebarText.textContent = b.org_name;

    // Splash hero wordmark
    const wordmark = document.getElementById('brandWordmark');
    if (wordmark && b.org_name) wordmark.textContent = b.org_name;

    // Splash headline — replace if branding provides it
    if (b.headline) {
        const headline = document.getElementById('brandHeadline');
        if (headline) headline.textContent = b.headline;
    }

    // Splash tagline
    const tagline = document.getElementById('brandTagline');
    if (tagline && b.tagline) tagline.textContent = b.tagline;

    // Auth card text
    if (b.org_name) {
        const authHeader = document.querySelector('.auth-card-header h2');
        if (authHeader) authHeader.textContent = 'Welcome to ' + b.org_name;
        const authSub = document.querySelector('.auth-card-header p');
        if (authSub) authSub.textContent = 'Sign in to continue';
    }
    const authFooter = document.getElementById('brandAuthFooter');
    if (authFooter && b.tagline) authFooter.textContent = b.tagline;

    // Logo — replace SVG with <img> in splash hero
    if (b.logo) {
        const logoUrl = brandBase + b.logo;

        const logoEl = document.getElementById('brandLogo');
        if (logoEl) {
            const img = document.createElement('img');
            img.src = logoUrl;
            img.alt = b.org_name || 'Logo';
            img.className = 'hero-logo-img';
            img.onerror = function() {
                this.style.display = 'none';
                const svg = logoEl.querySelector('svg');
                if (svg) svg.style.display = '';
            };
            const svg = logoEl.querySelector('svg');
            if (svg) svg.style.display = 'none';
            logoEl.appendChild(img);
        }

        // Sidebar logo — replace emoji with small img
        const sidebarLogo = document.getElementById('brandSidebarLogo');
        if (sidebarLogo) {
            const originalEmoji = sidebarLogo.textContent;
            const img = document.createElement('img');
            img.src = logoUrl;
            img.alt = '';
            img.className = 'brand-logo-img';
            img.onerror = function() {
                this.remove();
                sidebarLogo.textContent = originalEmoji;
            };
            sidebarLogo.textContent = '';
            sidebarLogo.appendChild(img);
        }
    }

    // Favicon
    if (b.favicon) {
        const favUrl = brandBase + b.favicon;
        document.querySelectorAll('link[rel="icon"], link[rel="apple-touch-icon"]').forEach(link => {
            link.href = favUrl;
        });
    }

    // Feature pills — custom array replaces defaults, empty array hides them
    if (b.pills !== undefined) {
        const pillsEl = document.getElementById('brandPills');
        if (pillsEl) {
            if (!Array.isArray(b.pills) || b.pills.length === 0) {
                pillsEl.style.display = 'none';
            } else {
                pillsEl.innerHTML = b.pills.map(p => {
                    const style = p.style === 'accent' ? ' accent' : p.style === 'purple' ? ' purple' : '';
                    return `<div class="hero-pill${style}"><span class="pill-icon">${p.icon || ''}</span> ${p.text}</div>`;
                }).join('');
            }
        }
    }

    console.log('🎨 Branding applied:', b.org_name || '(defaults)');
}

// ── Banners ──────────────────────────────────

async function initBanners() {
    try {
        const data = await API.getPublicSettings?.() || {};

        // Store policies for user-facing checks (allow_user_byok, etc.)
        App.policies = data.policies || {};

        // Storage capabilities (file upload, vision)
        App.storageConfigured = !!data.storage_configured;

        // Paste-to-file threshold (synced from backend, default 2000)
        App.pasteToFileChars = data.paste_to_file_chars || 2000;

        // Also flatten into serverSettings for backward compat
        App.serverSettings = {};
        if (data.banner)   App.serverSettings.banner   = data.banner;
        if (data.branding) App.serverSettings.branding = data.branding;

        const root = document.documentElement;
        const banner = data.banner;

        // Clear previous banner state
        ['bannerTop', 'bannerBottom'].forEach(id => {
            const el = document.getElementById(id);
            if (el) { el.classList.remove('active'); el.textContent = ''; }
        });
        root.style.setProperty('--banner-top-height', '0px');
        root.style.setProperty('--banner-bottom-height', '0px');

        if (!banner || !banner.enabled) return;

        root.style.setProperty('--banner-bg', banner.bg || '#007a33');
        root.style.setProperty('--banner-fg', banner.fg || '#ffffff');

        const text = banner.text || '';
        const pos = banner.position || 'both';

        if (pos === 'top' || pos === 'both') {
            const el = document.getElementById('bannerTop');
            el.textContent = text;
            el.classList.add('active');
            root.style.setProperty('--banner-top-height', '22px');
        }
        if (pos === 'bottom' || pos === 'both') {
            const el = document.getElementById('bannerBottom');
            el.textContent = text;
            el.classList.add('active');
            root.style.setProperty('--banner-bottom-height', '22px');
        }
    } catch (e) {
        // Banners are optional — non-admin users may not have access to settings
        console.debug('Banner init skipped:', e.message);
    }
}

// ── Boot ─────────────────────────────────────
document.addEventListener('DOMContentLoaded', init);