/**
 * javascript/app.js
 *
 * Shared runtime for the Podman plugin page: the AJAX helper every panel
 * module uses to talk to webui/plugins/podman/ajax/*.php, small DOM
 * utilities to avoid repeating the same escaping/formatting logic in ten
 * places, and the sub-tab router that shows/hides panels and lazily
 * initializes each one's module the first time it's opened.
 *
 * Loaded first (before any panel module) — see Podman.page.
 */
window.Podman = (function () {
  'use strict';

  const BASE = '/plugins/podman/ajax/';

  /**
   * Calls one ajax/<file>.php?action=<action> endpoint and resolves with
   * response.data, or rejects with an Error carrying the server's message
   * — every ajax/*.php endpoint replies with the same {ok, data|error}
   * envelope (see include/helpers.php's podman_json_response/_error), so
   * this one function is the only place that envelope shape is known.
   *
   * @param {string} file      e.g. "containers"
   * @param {string} action    e.g. "list"
   * @param {('GET'|'POST')} method
   * @param {object|null} body sent as JSON for POST
   * @param {object} query     extra query-string params (e.g. {id: "..."})
   */
  function call(file, action, method, body, query) {
    const params = new URLSearchParams(Object.assign({ action: action }, query || {}));
    const url = BASE + file + '.php?' + params.toString();

    const opts = { method: method, headers: {} };
    if (body !== undefined && body !== null) {
      opts.headers['Content-Type'] = 'application/json';
      opts.body = JSON.stringify(body);
    }

    return fetch(url, opts)
      .then(function (res) {
        return res.json().then(function (envelope) {
          if (!envelope.ok) {
            throw new Error(envelope.error || ('Request failed (' + res.status + ')'));
          }
          return envelope.data;
        });
      });
  }

  function get(file, action, query) {
    return call(file, action, 'GET', null, query);
  }

  function post(file, action, body) {
    return call(file, action, 'POST', body || {}, {});
  }

  // --- DOM helpers ---------------------------------------------------------

  function escapeHtml(value) {
    return String(value == null ? '' : value).replace(/[&<>"']/g, function (c) {
      return { '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[c];
    });
  }

  function el(id) {
    return document.getElementById(id);
  }

  function formatBytes(bytes) {
    if (!bytes || bytes <= 0) return '0 B';
    const units = ['B', 'KB', 'MB', 'GB', 'TB'];
    const i = Math.min(Math.floor(Math.log(bytes) / Math.log(1024)), units.length - 1);
    const value = bytes / Math.pow(1024, i);
    return (value >= 100 || i === 0 ? value.toFixed(0) : value.toFixed(1)) + ' ' + units[i];
  }

  function formatDuration(seconds) {
    if (seconds == null) return '—';
    if (seconds < 60) return seconds + 's';
    const days = Math.floor(seconds / 86400);
    const hours = Math.floor((seconds % 86400) / 3600);
    const minutes = Math.floor((seconds % 3600) / 60);
    if (days > 0) return days + 'd ' + hours + 'h';
    if (hours > 0) return hours + 'h ' + minutes + 'm';
    return minutes + 'm';
  }

  function formatRelativeTime(unixSeconds) {
    if (!unixSeconds) return '—';
    const diff = Math.max(0, Math.floor(Date.now() / 1000) - unixSeconds);
    if (diff < 60) return 'just now';
    if (diff < 3600) return Math.floor(diff / 60) + 'm ago';
    if (diff < 86400) return Math.floor(diff / 3600) + 'h ago';
    return Math.floor(diff / 86400) + 'd ago';
  }

  /** Status string (from libpod's container "State") -> chip color class. */
  function stateChipClass(state) {
    switch (state) {
      case 'running': return 'podman-chip-good';
      case 'paused': return 'podman-chip-warn';
      case 'exited':
      case 'created': return 'podman-chip-neutral';
      default: return 'podman-chip-bad';
    }
  }

  function loadingRow(colspan, label) {
    return '<tr><td colspan="' + colspan + '" class="podman-loading">' + escapeHtml(label || 'Loading…') + '</td></tr>';
  }

  function errorRow(colspan, message) {
    return '<tr><td colspan="' + colspan + '" class="podman-error">' + escapeHtml(message) + '</td></tr>';
  }

  // --- Panel router ----------------------------------------------------------

  const panelModules = {};
  const initialized = {};

  /** Called by each panel's own JS file (e.g. containers.js) to register itself. */
  function registerPanel(name, module) {
    panelModules[name] = module;
  }

  function activatePanel(name) {
    document.querySelectorAll('.podman-subnav button').forEach(function (btn) {
      btn.classList.toggle('active', btn.dataset.panel === name);
    });
    document.querySelectorAll('.podman-panel').forEach(function (panel) {
      panel.classList.toggle('active', panel.id === 'podman-panel-' + name);
    });

    const module = panelModules[name];
    if (!module) return;

    if (!initialized[name]) {
      initialized[name] = true;
      if (typeof module.init === 'function') module.init();
    } else if (typeof module.refresh === 'function') {
      module.refresh();
    }
  }

  function boot() {
    const subnav = document.querySelector('.podman-subnav');
    if (!subnav) return;

    subnav.addEventListener('click', function (e) {
      const btn = e.target.closest('button[data-panel]');
      if (btn) activatePanel(btn.dataset.panel);
    });

    const refreshBtn = el('podman-refresh-all');
    if (refreshBtn) {
      refreshBtn.addEventListener('click', function () {
        const active = document.querySelector('.podman-subnav button.active');
        if (active) activatePanel(active.dataset.panel);
      });
    }

    // Activate whichever panel is marked active in the initial HTML
    // (Dashboard, by default — see Podman.page).
    const initial = document.querySelector('.podman-subnav button.active');
    activatePanel(initial ? initial.dataset.panel : 'dashboard');
  }

  document.addEventListener('DOMContentLoaded', boot);

  return {
    get: get,
    post: post,
    escapeHtml: escapeHtml,
    el: el,
    formatBytes: formatBytes,
    formatDuration: formatDuration,
    formatRelativeTime: formatRelativeTime,
    stateChipClass: stateChipClass,
    loadingRow: loadingRow,
    errorRow: errorRow,
    registerPanel: registerPanel,
    activatePanel: activatePanel,
  };
})();