// ── router.js — SPA routing, navigation, breadcrumbs ─────
// Circular imports with page modules are safe: all cross-module
// accesses happen inside function bodies, never at module init time.

import { escapeHTML } from './utils.js';
import { agentsState } from './state.js';
import { resetNavController } from './nav-signal.js';

import { renderDashboard, cleanup as cleanupDashboard }       from './pages/dashboard.js';
import { renderSessions, cleanup as cleanupSessions }         from './pages/sessions.js';
import { renderSession, cleanup as cleanupSessionDetail }     from './pages/session-detail.js';
import { renderRun, cleanup as cleanupRunDetail }             from './pages/run-detail.js';
import { renderAgents, cleanup as cleanupAgents }             from './pages/agents.js';
import { renderInfrastructure, cleanup as cleanupInfra }      from './pages/infrastructure.js';
import { renderSettings }                                     from './pages/settings.js';
import { renderUsage, cleanup as cleanupUsage }              from './pages/usage.js';

// Exported so all page modules can write into it without querying the DOM each time
export const app = document.getElementById('app');

let currentRouteToken = 0;

export function isRouteCurrent(token) {
  return token === currentRouteToken;
}

export function cleanupLiveViews() {
  cleanupInfra();
  cleanupAgents();
  cleanupSessions();
  cleanupSessionDetail();
  cleanupRunDetail();
  cleanupDashboard();
  cleanupUsage();
}

export function route() {
  const routeToken = ++currentRouteToken;
  resetNavController();
  cleanupLiveViews();
  renderBreadcrumbs();

  app.classList.add('transitioning');
  const path = window.location.pathname;

  const safeRender = (fn) => {
    if (!isRouteCurrent(routeToken)) return;
    Promise.resolve().then(() => {
      if (!isRouteCurrent(routeToken)) return null;
      return fn(routeToken);
    }).catch(err => {
      if (!isRouteCurrent(routeToken)) return;
      if (err && err.name === 'AbortError') return; // route changed mid-fetch
      console.error('Render error:', err);
      app.innerHTML = `
        <div class="error-boundary">
          <h2>Something went wrong</h2>
          <p>An error occurred while rendering this page.</p>
          <pre class="error-boundary-detail">${escapeHTML(err.message)}</pre>
          <a href="/" class="back-link">Back to Dashboard</a>
        </div>
      `;
    });
  };

  if (path === '/') {
    safeRender((token) => renderDashboard(token));
  } else if (path === '/sessions') {
    safeRender((token) => renderSessions(token));
  } else if (path.startsWith('/agents/')) {
    const agentKey = decodeURIComponent(path.split('/agents/')[1]);
    safeRender((token) => renderAgents(agentKey, token));
  } else if (path.startsWith('/agents')) {
    safeRender((token) => renderAgents(undefined, token));
  } else if (path.startsWith('/infrastructure')) {
    safeRender((token) => renderInfrastructure(token));
  } else if (path.startsWith('/sessions/')) {
    safeRender((token) => renderSession(path.split('/sessions/')[1], token));
  } else if (path.startsWith('/runs/')) {
    safeRender((token) => renderRun(path.split('/runs/')[1], token));
  } else if (path === '/settings') {
    safeRender((token) => renderSettings(token));
  } else if (path === '/usage') {
    safeRender((token) => renderUsage(token));
  } else {
    app.innerHTML = '<div class="not-found"><h2>Page not found</h2><p>The page you\'re looking for doesn\'t exist.</p><a href="/" class="back-link">Go to Dashboard</a></div>';
  }
  updateActiveNav();

  requestAnimationFrame(() => {
    if (isRouteCurrent(routeToken)) app.classList.remove('transitioning');
  });
}

export function renderBreadcrumbs() {
  const el = document.getElementById('breadcrumbs');
  if (!el) return;

  const path = window.location.pathname;
  const parts = path.split('/').filter(Boolean);
  if (parts.length === 0) {
    el.innerHTML = '';
    return;
  }

  const items = [{ label: 'Dashboard', path: '/' }];
  let currentPath = '';

  parts.forEach((part, i) => {
    currentPath += '/' + part;
    let label = part.charAt(0).toUpperCase() + part.slice(1);

    // Special labels for IDs
    if (part.length > 20 || /^[a-f0-9-]{32,}$/.test(part)) {
      label = part.substring(0, 8) + '…';
    }

    // For /agents/:key, show the human-readable agent name
    if (parts[0] === 'agents' && i === 1) {
      const agentKey = decodeURIComponent(part);
      const agent = agentsState && agentsState.agents && agentsState.agents[agentKey];
      label = (agent && agent.name) ? agent.name : agentKey;
    }

    if (i === parts.length - 1) {
      items.push({ label, current: true });
    } else {
      items.push({ label, path: currentPath });
    }
  });

  // No inline onclick — the delegated <a> click handler in app.js picks these up.
  el.innerHTML = items.map(item => {
    if (item.current) {
      return `<span class="current">${escapeHTML(item.label)}</span>`;
    }
    return `<a href="${escapeHTML(item.path)}">${escapeHTML(item.label)}</a><span class="sep">/</span>`;
  }).join('');
}

export function navigate(path) {
  history.pushState(null, '', path);
  route();
}

export function updateActiveNav() {
  const path = window.location.pathname;
  document.querySelectorAll('header nav a').forEach(a => {
    const href = a.getAttribute('href');
    const isActive = href === '/'
      ? path === '/'
      : path.startsWith(href);
    a.classList.toggle('active', isActive);
  });
}

window.addEventListener('popstate', route);