Hermit/app/src/platform/linux/NotifyTool.cpp

/* Platform tools on Linux, implemented by the app (not by the engine): they
 * exist exactly where the desktop service does, and the engine only ever sees
 * the capability -- platforms + probe decide whether the tool is offered. */

#include <QByteArray>
#include <QFileInfo>
#include <QProcess>
#include <QString>
#include <QStringList>

#include <cstdio>
#include <cstring>

#include "core/AgentCore.h"
#include "core/ToolProvider.h"

namespace app {
namespace {

/* whereis-style check without a shell: the same rule the engine uses for the
 * clipboard helpers. */
bool haveProgram(const char *name) {
  QByteArray path = qgetenv("PATH");
  const QList<QByteArray> dirs = path.split(':');
  for (const QByteArray &d : dirs) {
    QByteArray dir = d.isEmpty() ? QByteArray(".") : d;
    QByteArray cand = dir + "/" + name;
    if (QFileInfo::exists(QString::fromLocal8Bit(cand)) &&
        QFileInfo(QString::fromLocal8Bit(cand)).isExecutable())
      return true;
  }
  return false;
}

/* 0 when notifications can be shown; -1 with the reason otherwise. */
int notifyProbe(char *why, size_t why_sz) {
  if (haveProgram("notify-send"))
    return 0;
  if (haveProgram("gdbus") && !qgetenv("DBUS_SESSION_BUS_ADDRESS").isEmpty())
    return 0;
  snprintf(why, why_sz,
           "no notification service (no notify-send, no D-Bus session bus)");
  return -1;
}

const char *argOf(const ctl_tool_call_t *call, const char *key) {
  for (int i = 0; i < call->nargs; i++)
    if (strcmp(call->args[i].key, key) == 0)
      return call->args[i].value;
  return nullptr;
}

/* Runs on the turn's worker thread: no GUI objects here. */
int notifyRun(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *call,
              cst_tool_result_t *r, void *ud) {
  (void)ctx;
  (void)ud;
  const char *title = argOf(call, "title");
  const char *message = argOf(call, "message");
  if (!message || !message[0]) {
    const char *msg = "error: notification_send needs a message";
    r->out = strdup(msg);
    r->out_len = r->out ? strlen(msg) : 0;
    r->exit_code = 1;
    return 0;
  }
  QStringList args;
  if (title && title[0])
    args << QString::fromUtf8(title);
  else
    args << QStringLiteral("CST-agent");
  args << QString::fromUtf8(message);
  const int rc = QProcess::execute(QStringLiteral("notify-send"), args);
  const QByteArray text =
      (rc == 0 ? QByteArrayLiteral("notification sent")
               : QByteArrayLiteral("notify-send failed (rc=") +
                     QByteArray::number(rc) + QByteArrayLiteral(")"));
  r->out = strdup(text.constData());
  r->out_len = r->out ? strlen(r->out) : 0;
  r->exit_code = rc == 0 ? 0 : 1;
  return 0;
}

/* Registered once; the engine keeps a copy until the owner is unregistered. */
cst_tool_def_t g_notify;

}  // namespace

int platformRegisterLinux(AgentCore *core) {
  static const cst_tool_param_t params[CST_TOOL_MAX_PARAMS] = {
      {"message", "string", 1, "text of the notification"},
      {"title", "string", 0, "title line (default: CST-agent)"},
      {nullptr, nullptr, 0, nullptr},
      {nullptr, nullptr, 0, nullptr},
      {nullptr, nullptr, 0, nullptr},
      {nullptr, nullptr, 0, nullptr}};
  memset(&g_notify, 0, sizeof(g_notify));
  setMeta(&g_notify, "notification_send",
          "Show a desktop notification (what the user sees outside the app).",
          CST_TP_ASK, "notify", kDesktopOnly, notifyProbe);
  memcpy(g_notify.params, params, sizeof(params));
  g_notify.run = nullptr;
  g_notify.run_ex = notifyRun;
  g_notify.ud = nullptr;
  g_notify.owner = "app:linux";
  return core->registerTool(&g_notify) ? 1 : 0;
}

}  // namespace app