/**
 * javascript/terminal.js
 *
 * Terminal panel: one-command-at-a-time exec via ajax/exec.php. See that
 * file's header comment for the full, honest explanation of why this is
 * "type a command, see its output" rather than a true interactive PTY —
 * the short version is that libpod's interactive exec needs a persistent
 * bidirectional connection this PHP/AJAX stack doesn't have, and faking
 * interactivity on top of that would break the moment a user ran anything
 * that expects a real terminal (vim, an interactive prompt, etc).
 *
 * `cd` is handled client-side: this module tracks a per-session `cwd` and
 * passes it as the exec's working directory on every call, so at least
 * directory navigation feels persistent even though nothing else is.
 */
(function () {
  'use strict';
  const P = window.Podman;
  let cwd = '/';
  let containerId = null;

  function appendLine(html) {
    const out = P.el('term-output');
    const div = document.createElement('div');
    div.innerHTML = html;
    out.appendChild(div);
    out.scrollTop = out.scrollHeight;
  }

  function promptHtml() {
    return '<span class="prompt">root</span>:<span class="path">' + P.escapeHtml(cwd) + '</span>$';
  }

  function runCommand(cmd) {
    appendLine(promptHtml() + ' ' + P.escapeHtml(cmd));

    // `cd <dir>` is intercepted client-side (see file header) rather than
    // sent as a real command, since a one-shot exec has no way to report
    // "the working directory changed" back to us otherwise.
    const cdMatch = cmd.trim().match(/^cd\s+(\S+)$/);
    if (cdMatch) {
      cwd = cdMatch[1].startsWith('/') ? cdMatch[1] : (cwd.replace(/\/$/, '') + '/' + cdMatch[1]);
      return Promise.resolve();
    }

    return P.post('exec', 'run', { id: containerId, cmd: cmd, cwd: cwd }).then(function (data) {
      if (data.output) appendLine('<span class="mono">' + P.escapeHtml(data.output).replace(/\n/g, '<br>') + '</span>');
    }).catch(function (err) {
      appendLine('<span style="color:#ef6470;">' + P.escapeHtml(err.message) + '</span>');
    });
  }

  function populateContainerSelect(containers) {
    const select = P.el('term-container-select');
    select.innerHTML = containers
      .filter(function (c) { return c.state === 'running'; })
      .map(function (c) { return '<option value="' + P.escapeHtml(c.id) + '">' + P.escapeHtml(c.name) + '</option>'; })
      .join('');
    containerId = select.value || null;
  }

  function init() {
    const input = P.el('term-input');

    P.el('term-container-select').addEventListener('change', function (e) {
      containerId = e.target.value;
      cwd = '/';
      P.el('term-output').innerHTML = '';
    });

    input.addEventListener('keydown', function (e) {
      if (e.key !== 'Enter') return;
      const cmd = input.value;
      input.value = '';
      if (!containerId) {
        appendLine('<span style="color:#ef6470;">No running container selected.</span>');
        return;
      }
      if (cmd.trim() === '') return;
      runCommand(cmd);
    });

    return P.get('containers', 'list').then(populateContainerSelect).catch(function (err) {
      appendLine('<span style="color:#ef6470;">' + P.escapeHtml(err.message) + '</span>');
    });
  }

  P.registerPanel('terminal', { init: init });
})();