/* Platform tools on Android, implemented by the app: the same contract as
 * app/src/platform/linux/NotifyTool.cpp, with Android APIs behind it.
 *
 * The engine only ever sees the capability: `platforms = kAndroidOnly` (the
 * engine reports "android" when it was compiled with the NDK, see
 * src/tools/registry.c: cst_platform_name()) plus an `available` probe decide
 * whether a tool reaches the prompt and tools[] at all -- a Termux build on
 * the same device reports "termux" and gets the android tools too, an APK
 * never gets the desktop ones. `owner = "app:android"` is what
 * unregisterPlatformTools() drops again.
 *
 * WHERE THE CODE RUNS: `run_ex` is called on the turn's worker thread, never
 * on the GUI thread. JNI calls are fine from any thread (Qt attaches it),
 * Qt GUI objects are not -- a tool that needs the widget tree
 * has to hop back with a blocking queued call (onGuiThread() below).
 *
 * The clipboard tools keep the names of the engine's built-ins: those are
 * gated to CST_PLAT_DESKTOP and the registry lets an app tool of the same
 * name shadow the built-in (src/tools/registry.c: cst_tool_find()), so the
 * model sees one capability either way. */
#include <QByteArray>
#include <QClipboard>
#include <QCoreApplication>
#include <QDir>
#include <QFileInfo>
#include <QFuture>
#include <QGuiApplication>
#include <QJniObject>
#include <QMetaObject>
#include <QStandardPaths>
#include <QString>
#include <QStringList>
#include <QThread>

#include <QtCore/private/qandroidextras_p.h>

#include <cstdio>
#include <cstring>
#include <utility>

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

namespace app {
namespace {

/* --- small helpers ------------------------------------------------------- */

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;
}

void setOut(cst_tool_result_t *r, const QByteArray &text, int rc) {
  r->out = strdup(text.constData());
  r->out_len = r->out ? strlen(r->out) : 0;
  r->exit_code = rc;
}

/* Anything that touches a Qt GUI object (the clipboard) or an Activity has to
 * run on the GUI thread; the turn's worker thread waits for it. */
template <typename Fn>
void onGuiThread(Fn &&fn) {
  if (!qApp || QThread::currentThread() == qApp->thread()) {
    fn();
    return;
  }
  QMetaObject::invokeMethod(qApp, std::forward<Fn>(fn),
                            Qt::BlockingQueuedConnection);
}

jint sdkInt() {
  static const jint sdk = QJniObject::getStaticField<jint>(
      "android/os/Build$VERSION", "SDK_INT");
  return sdk;
}

QJniObject appContext() {
  return QNativeInterface::QAndroidApplication::context();
}

/* --- notification_send --------------------------------------------------- */

/* Android 13 (API 33) put notifications behind a runtime permission; before
 * that the permission does not exist and they always work. main.cpp asks for
 * it once at startup, so the probe is normally green on a device where the
 * user said yes. */
int notifyProbe(char *why, size_t why_sz) {
  if (sdkInt() < 33)
    return 0;
  const QFuture<QtAndroidPrivate::PermissionResult> f =
      QtAndroidPrivate::checkPermission(
          QStringLiteral("android.permission.POST_NOTIFICATIONS"));
  if (f.result() == QtAndroidPrivate::Authorized)
    return 0;
  snprintf(why, why_sz,
           "POST_NOTIFICATIONS is not granted (Android 13+ asks the user the "
           "first time the app runs)");
  return -1;
}

bool postNotification(const QString &title, const QString &message,
                      QString *err) {
  QJniObject ctx = appContext();
  if (!ctx.isValid()) {
    *err = QStringLiteral("no Android context");
    return false;
  }
  QJniObject manager = ctx.callObjectMethod(
      "getSystemService", "(Ljava/lang/String;)Ljava/lang/Object;",
      QJniObject::fromString(QStringLiteral("notification")).object<jstring>());
  if (!manager.isValid()) {
    *err = QStringLiteral("no NotificationManager");
    return false;
  }

  const QString channelId = QStringLiteral("cst-agent");
  if (sdkInt() >= 26) {
    QJniObject channel(
        "android/app/NotificationChannel",
        "(Ljava/lang/String;Ljava/lang/CharSequence;I)V",
        QJniObject::fromString(channelId).object<jstring>(),
        QJniObject::fromString(QStringLiteral("CST-agent")).object<jstring>(),
        static_cast<jint>(3) /* IMPORTANCE_DEFAULT */);
    manager.callMethod<void>("createNotificationChannel",
                             "(Landroid/app/NotificationChannel;)V",
                             channel.object<jobject>());
  }

  /* The small icon. The R classes are not reachable from here, so the id is
   * looked up by name, and build() throws IllegalArgumentException ("Invalid
   * notification (no valid small icon)") when there is none at all: every
   * candidate that can be there is tried -- the framework drawables first,
   * then the launcher icon the APK itself carries (AGP puts it in mipmap, a
   * hand made APK in drawable/icon). */
  QJniObject res = ctx.callObjectMethod("getResources",
                                        "()Landroid/content/res/Resources;");
  QJniObject pkg = ctx.callObjectMethod("getPackageName",
                                        "()Ljava/lang/String;");
  jint icon = 0;
  if (res.isValid()) {
    auto idOf = [&res, &pkg](const char *name, const char *type,
                             const char *owner) {
      return res.callMethod<jint>(
          "getIdentifier", "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)I",
          QJniObject::fromString(QString::fromLatin1(name)).object<jstring>(),
          QJniObject::fromString(QString::fromLatin1(type)).object<jstring>(),
          owner ? QJniObject::fromString(QString::fromLatin1(owner)).object<jstring>()
                : pkg.object<jstring>());
    };
    for (const char *n : {"ic_dialog_info", "ic_popup_reminder",
                          "stat_notify_chat", "sym_def_app_icon"}) {
      icon = idOf(n, "drawable", "android");
      if (icon != 0)
        break;
    }
    for (const char *n : {"ic_launcher", "icon", "app_icon", "qt_icon"}) {
      if (icon == 0)
        icon = idOf(n, "mipmap", nullptr);
      if (icon == 0)
        icon = idOf(n, "drawable", nullptr);
      if (icon != 0)
        break;
    }
  }
  if (icon == 0) {
    *err = QStringLiteral("no small icon: it is in neither the framework "
                          "resources nor the APK's own");
    return false;
  }
  /* Tapping it opens the app again (the launch intent of the package). */
  QJniObject pm = ctx.callObjectMethod(
      "getPackageManager", "()Landroid/content/pm/PackageManager;");
  /* The builder, the build and the notify happen in Java (Notifier.java):
   * a Java exception is invisible to C++ once Qt's JNI wrapper has cleared
   * it, so on the phone this only ever said "failed, no exception detail"
   * while the shade stayed empty. Java catches it and hands back the line to
   * show. */
  QJniObject launch;
  if (pm.isValid() && pkg.isValid())
    launch = pm.callObjectMethod(
        "getLaunchIntentForPackage",
        "(Ljava/lang/String;)Landroid/content/Intent;", pkg.object<jstring>());
  QJniObject posted = QJniObject::callStaticObjectMethod(
      "xyz/whcself/cstagent/Notifier", "post",
      "(Landroid/content/Context;Ljava/lang/String;Ljava/lang/String;"
      "Ljava/lang/String;ILandroid/content/Intent;I)Ljava/lang/String;",
      ctx.object<jobject>(),
      QJniObject::fromString(channelId).object<jstring>(),
      QJniObject::fromString(title).object<jstring>(),
      QJniObject::fromString(message).object<jstring>(), icon,
      launch.isValid() ? launch.object<jobject>() : nullptr,
      static_cast<jint>(1));
  const QString java =
      posted.isValid() ? posted.toString()
                       : QStringLiteral("the Notifier helper is not in this APK");
  if (!java.isEmpty()) {
    *err = QStringLiteral("cannot post the notification: %1").arg(java);
    return false;
  }
  return true;
}

/* 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 *message = argOf(call, "message");
  const char *title = argOf(call, "title");
  if (!message || !message[0]) {
    setOut(r, QByteArrayLiteral("error: notification_send needs a message"), 1);
    return 0;
  }
  const QString t = title && title[0] ? QString::fromUtf8(title)
                                      : QStringLiteral("CST-agent");
  const QString m = QString::fromUtf8(message);
  QString err;
  bool ok = false;
  onGuiThread([&] { ok = postNotification(t, m, &err); });
  if (ok)
    setOut(r, QByteArrayLiteral("notification sent"), 0);
  else
    setOut(r, QByteArrayLiteral("error: ") + err.toUtf8(), 1);
  return 0;
}

/* --- clipboard_read / clipboard_write ----------------------------------- */

int clipboardProbe(char *why, size_t why_sz) {
  if (QGuiApplication::clipboard())
    return 0;
  snprintf(why, why_sz, "no QClipboard (no GUI application)");
  return -1;
}

int clipboardReadRun(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 *cap = argOf(call, "max_bytes");
  const long max =
      cap && cap[0] ? strtol(cap, nullptr, 10) : 65536L;
  QString text;
  bool have = false;
  onGuiThread([&] {
    if (QClipboard *cb = QGuiApplication::clipboard()) {
      text = cb->text();
      have = true;
    }
  });
  if (!have) {
    setOut(r, QByteArrayLiteral("error: no clipboard"), 1);
    return 0;
  }
  QByteArray body = text.toUtf8();
  const bool cut = max > 0 && body.size() > max;
  if (cut)
    body.truncate(static_cast<int>(max));
  QByteArray out =
      QByteArrayLiteral("clipboard text (") + QByteArray::number(body.size()) +
      QByteArrayLiteral(" bytes") +
      (cut ? QByteArrayLiteral(", truncated") : QByteArray()) +
      QByteArrayLiteral("):\n") + body + QByteArrayLiteral("\n");
  setOut(r, out, 0);
  return 0;
}

int clipboardWriteRun(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 *text = argOf(call, "text");
  if (!text) {
    setOut(r, QByteArrayLiteral("error: clipboard_write needs text"), 1);
    return 0;
  }
  const QString t = QString::fromUtf8(text);
  bool ok = false;
  onGuiThread([&] {
    if (QClipboard *cb = QGuiApplication::clipboard()) {
      cb->setText(t);
      ok = true;
    }
  });
  if (ok)
    setOut(r, QByteArrayLiteral("clipboard: replaced with ") +
                  QByteArray::number(t.toUtf8().size()) +
                  QByteArrayLiteral(" bytes"),
           0);
  else
    setOut(r, QByteArrayLiteral("error: no clipboard"), 1);
  return 0;
}

/* --- share --------------------------------------------------------------- */

/* A path inside the workspace, resolved the way the engine's file tools do:
 * relative to the workspace and never outside it. */
QString resolveInWorkspace(const cst_tool_ctx_t *ctx, const char *rel) {
  if (!ctx || !ctx->workspace_root || !rel || !rel[0])
    return QString();
  const QString root = QDir::cleanPath(QString::fromUtf8(ctx->workspace_root));
  const QString full = QDir::cleanPath(root + QLatin1Char('/') +
                                       QString::fromUtf8(rel));
  if (full != root && !full.startsWith(root + QLatin1Char('/')))
    return QString();
  return full;
}

QString mimeOf(const QString &path) {
  const QString ext = QFileInfo(path).suffix().toLower();
  if (ext == QLatin1String("png")) return QStringLiteral("image/png");
  if (ext == QLatin1String("jpg") || ext == QLatin1String("jpeg"))
    return QStringLiteral("image/jpeg");
  if (ext == QLatin1String("webp")) return QStringLiteral("image/webp");
  if (ext == QLatin1String("gif")) return QStringLiteral("image/gif");
  if (ext == QLatin1String("pdf")) return QStringLiteral("application/pdf");
  if (ext == QLatin1String("json")) return QStringLiteral("application/json");
  if (ext == QLatin1String("txt") || ext == QLatin1String("md") ||
      ext == QLatin1String("log"))
    return QStringLiteral("text/plain");
  return QStringLiteral("*/*");
}

/* ACTION_SEND through the system share sheet. `text` shares a sentence (the
 * usual case: the user takes it to another app), `file` shares one file out of
 * the workspace by way of the FileProvider Qt's manifest template declares
 * (androidx.core.content.FileProvider, authority <package>.qtprovider). */
bool shareText(const QString &text, const QString &subject, QString *err) {
  QJniObject ctx = appContext();
  if (!ctx.isValid()) {
    *err = QStringLiteral("no Android context");
    return false;
  }
  QJniObject send = QJniObject::fromString(QStringLiteral("android.intent.action.SEND"));
  QJniObject intent("android/content/Intent", "(Ljava/lang/String;)V",
                    send.object<jstring>());
  intent.callObjectMethod("setType",
                          "(Ljava/lang/String;)Landroid/content/Intent;",
                          QJniObject::fromString(QStringLiteral("text/plain"))
                              .object<jstring>());
  intent.callObjectMethod(
      "putExtra",
      "(Ljava/lang/String;Ljava/lang/CharSequence;)Landroid/content/Intent;",
      QJniObject::fromString(QStringLiteral("android.intent.extra.TEXT"))
          .object<jstring>(),
      QJniObject::fromString(text).object<jstring>());
  if (!subject.isEmpty())
    intent.callObjectMethod(
        "putExtra",
        "(Ljava/lang/String;Ljava/lang/CharSequence;)Landroid/content/Intent;",
        QJniObject::fromString(QStringLiteral("android.intent.extra.SUBJECT"))
            .object<jstring>(),
        QJniObject::fromString(subject).object<jstring>());
  QJniObject chooser("android/content/Intent", "(Ljava/lang/String;)V",
                     QJniObject::fromString(QStringLiteral("android.intent.action.CHOOSER"))
                         .object<jstring>());
  /* Intent.createChooser(Intent, CharSequence) -- the share sheet itself. */
  QJniObject sheet = QJniObject::callStaticObjectMethod(
      "android/content/Intent", "createChooser",
      "(Landroid/content/Intent;Ljava/lang/CharSequence;)Landroid/content/Intent;",
      intent.object<jobject>(),
      QJniObject::fromString(QStringLiteral("Share with")).object<jstring>());
  QJniObject toStart = sheet.isValid() ? sheet : intent;
  toStart.callObjectMethod("addFlags", "(I)Landroid/content/Intent;",
                           static_cast<jint>(0x10000000) /* NEW_TASK */);
  ctx.callMethod<void>("startActivity", "(Landroid/content/Intent;)V",
                       toStart.object<jobject>());
  return true;
}

/* The content:// uri of a file inside the app's own data directory. The
 * FileProvider and its paths xml come from Qt's manifest template
 * (authority <package>.qtprovider, files-path "/"), which covers the whole
 * workspace and the session store. */
QJniObject contentUriFor(const QString &path, QString *err) {
  QJniObject ctx = appContext();
  if (!ctx.isValid()) {
    *err = QStringLiteral("no Android context");
    return QJniObject();
  }
  QJniObject pkg = ctx.callObjectMethod("getPackageName", "()Ljava/lang/String;");
  const QString authority = pkg.toString() + QStringLiteral(".qtprovider");
  QJniObject file("java/io/File", "(Ljava/lang/String;)V",
                  QJniObject::fromString(path).object<jstring>());
  QJniObject uri = QJniObject::callStaticObjectMethod(
      "androidx/core/content/FileProvider", "getUriForFile",
      "(Landroid/content/Context;Ljava/lang/String;Ljava/io/File;)Landroid/net/Uri;",
      ctx.object<jobject>(),
      QJniObject::fromString(authority).object<jstring>(),
      file.object<jobject>());
  if (!uri.isValid())
    *err = QStringLiteral("the FileProvider did not hand out a uri for ") + path;
  return uri;
}

bool shareFile(const QString &path, const QString &text, QString *err) {
  QJniObject ctx = appContext();
  if (!ctx.isValid()) {
    *err = QStringLiteral("no Android context");
    return false;
  }
  QJniObject uri = contentUriFor(path, err);
  if (!uri.isValid())
    return false;
  QJniObject action = QJniObject::fromString(QStringLiteral("android.intent.action.SEND"));
  QJniObject intent("android/content/Intent", "(Ljava/lang/String;)V",
                    action.object<jstring>());
  intent.callObjectMethod("setType",
                          "(Ljava/lang/String;)Landroid/content/Intent;",
                          QJniObject::fromString(mimeOf(path)).object<jstring>());
  intent.callObjectMethod(
      "putExtra",
      "(Ljava/lang/String;Landroid/os/Parcelable;)Landroid/content/Intent;",
      QJniObject::fromString(QStringLiteral("android.intent.extra.STREAM"))
          .object<jstring>(),
      uri.object<jobject>());
  if (!text.isEmpty())
    intent.callObjectMethod(
        "putExtra",
        "(Ljava/lang/String;Ljava/lang/CharSequence;)Landroid/content/Intent;",
        QJniObject::fromString(QStringLiteral("android.intent.extra.TEXT"))
            .object<jstring>(),
        QJniObject::fromString(text).object<jstring>());
  intent.callObjectMethod(
      "addFlags", "(I)Landroid/content/Intent;",
      static_cast<jint>(0x10000000 /* NEW_TASK */ | 0x00000001 /* GRANT_READ_URI_PERMISSION */));
  QJniObject sheet = QJniObject::callStaticObjectMethod(
      "android/content/Intent", "createChooser",
      "(Landroid/content/Intent;Ljava/lang/CharSequence;)Landroid/content/Intent;",
      intent.object<jobject>(),
      QJniObject::fromString(QStringLiteral("Share with")).object<jstring>());
  QJniObject toStart = sheet.isValid() ? sheet : intent;
  toStart.callObjectMethod("addFlags", "(I)Landroid/content/Intent;",
                           static_cast<jint>(0x10000000));
  ctx.callMethod<void>("startActivity", "(Landroid/content/Intent;)V",
                       toStart.object<jobject>());
  return true;
}

int shareRun(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *call,
             cst_tool_result_t *r, void *ud) {
  (void)ud;
  const char *text = argOf(call, "text");
  const char *file = argOf(call, "file");
  const char *subject = argOf(call, "subject");
  if ((!text || !text[0]) && (!file || !file[0])) {
    setOut(r, QByteArrayLiteral("error: share needs text or file"), 1);
    return 0;
  }
  QString path;
  if (file && file[0]) {
    path = resolveInWorkspace(ctx, file);
    if (path.isEmpty() || !QFileInfo::exists(path)) {
      setOut(r, QByteArrayLiteral("error: ") + QByteArray(file) +
                    QByteArrayLiteral(" is not inside the workspace"),
             1);
      return 0;
    }
  }
  const QString body = text ? QString::fromUtf8(text) : QString();
  const QString subjectLine = subject ? QString::fromUtf8(subject) : QString();
  QString err;
  bool ok = false;
  onGuiThread([&] {
    ok = path.isEmpty() ? shareText(body, subjectLine, &err)
                        : shareFile(path, body, &err);
  });
  if (!ok) {
    setOut(r, QByteArrayLiteral("error: ") + err.toUtf8(), 1);
    return 0;
  }
  setOut(r, path.isEmpty()
                 ? QByteArrayLiteral("the share sheet is open with the text")
                 : QByteArrayLiteral("the share sheet is open with ") +
                       path.toUtf8(),
         0);
  return 0;
}

int shareProbe(char *why, size_t why_sz) {
  if (appContext().isValid())
    return 0;
  snprintf(why, why_sz, "no Android activity to share from");
  return -1;
}

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

}  // namespace

/* A file card's "open": whatever app the phone has for the type, with the read
 * permission granted to the app that picks it up. */
QString openLocalFile(const QString &path, const QString &title,
                      QString *status) {
  const QString name = title.isEmpty() ? QFileInfo(path).fileName() : title;
  if (qEnvironmentVariableIsSet("CST_APP_NO_OPEN")) {
    if (status)
      *status = QStringLiteral("opened %1 (test mode)").arg(name);
    return QString();
  }
  if (!QFileInfo::exists(path))
    return QStringLiteral("the file is gone: %1").arg(name);
  QString err;
  bool ok = false;
  onGuiThread([&] {
    QJniObject ctx = appContext();
    if (!ctx.isValid()) {
      err = QStringLiteral("no Android context");
      return;
    }
    QJniObject uri = contentUriFor(path, &err);
    if (!uri.isValid())
      return;
    QJniObject action =
        QJniObject::fromString(QStringLiteral("android.intent.action.VIEW"));
    QJniObject intent("android/content/Intent", "(Ljava/lang/String;)V",
                      action.object<jstring>());
    intent.callObjectMethod(
        "setDataAndType",
        "(Landroid/net/Uri;Ljava/lang/String;)Landroid/content/Intent;",
        uri.object<jobject>(),
        QJniObject::fromString(mimeOf(path)).object<jstring>());
    intent.callObjectMethod("addFlags", "(I)Landroid/content/Intent;",
                            static_cast<jint>(0x10000000 /* NEW_TASK */ |
                                              0x00000001 /* GRANT_READ_URI */));
    /* Nothing installed for the type: say so rather than fail silently. */
    QJniObject pm = ctx.callObjectMethod(
        "getPackageManager", "()Landroid/content/pm/PackageManager;");
    QJniObject found =
        pm.isValid()
            ? pm.callObjectMethod(
                  "resolveActivity",
                  "(Landroid/content/Intent;I)Landroid/content/pm/ResolveInfo;",
                  intent.object<jobject>(),
                  static_cast<jint>(0x00010000) /* MATCH_DEFAULT_ONLY */)
            : QJniObject();
    if (!found.isValid()) {
      err = QStringLiteral("no app on the phone opens %1").arg(name);
      return;
    }
    ctx.callMethod<void>("startActivity", "(Landroid/content/Intent;)V",
                         intent.object<jobject>());
    ok = true;
  });
  if (!ok)
    return err.isEmpty() ? QStringLiteral("cannot open %1").arg(name) : err;
  if (status)
    *status = QStringLiteral("opened %1").arg(name);
  return QString();
}

/* The share sheet, the same way the share tool opens it. */
QString shareLocalFile(const QString &path, const QString &title,
                       QString *status) {
  const QString name = title.isEmpty() ? QFileInfo(path).fileName() : title;
  if (qEnvironmentVariableIsSet("CST_APP_NO_OPEN")) {
    if (status)
      *status = QStringLiteral("shared %1 (test mode)").arg(name);
    return QString();
  }
  if (!QFileInfo::exists(path))
    return QStringLiteral("the file is gone: %1").arg(name);
  QString err;
  bool ok = false;
  onGuiThread([&] { ok = shareFile(path, QString(), &err); });
  if (!ok)
    return err.isEmpty() ? QStringLiteral("cannot share %1").arg(name) : err;
  if (status)
    *status = QStringLiteral("share sheet: %1").arg(name);
  return QString();
}

/* An Intent aimed at one of our own classes, by name: the Java side is
 * reached through an explicit component, so no other app can call it (and no
 * intent filter has to exist). Empty action means "start". */
QJniObject serviceIntent(const QJniObject &ctx, const QString &action) {
  QJniObject pkg = ctx.callObjectMethod("getPackageName",
                                        "()Ljava/lang/String;");
  if (!pkg.isValid())
    return QJniObject();
  QJniObject comp(
      "android/content/ComponentName", "(Ljava/lang/String;Ljava/lang/String;)V",
      pkg.object<jstring>(),
      QJniObject::fromString(
          QStringLiteral("xyz.whcself.cstagent.CstService"))
          .object<jstring>());
  if (!comp.isValid())
    return QJniObject();
  QJniObject intent("android/content/Intent");
  intent.callObjectMethod(
      "setComponent",
      "(Landroid/content/ComponentName;)Landroid/content/Intent;",
      comp.object<jobject>());
  if (!action.isEmpty())
    intent.callObjectMethod("setAction",
                            "(Ljava/lang/String;)Landroid/content/Intent;",
                            QJniObject::fromString(action).object<jstring>());
  return intent;
}

/* A turn can outlive the screen, and a phone freezes or kills an app it
 * cannot see: CstService (app/android/src/xyz/whcself/cstagent/CstService.java)
 * is started as a foreground service for as long as one runs, and it takes the
 * partial wake lock that keeps the CPU awake with the screen off. The explicit
 * component means nothing outside the app can start it. */
QString holdForeground(const QString &text) {
  if (qEnvironmentVariableIsSet("CST_APP_NO_SERVICE"))
    return QString(); /* a test run leaves the phone alone */
  QString err;
  onGuiThread([&] {
    QJniObject ctx = appContext();
    if (!ctx.isValid()) {
      err = QStringLiteral("no Android context");
      return;
    }
    QJniObject intent = serviceIntent(ctx, QString());
    if (!intent.isValid()) {
      err = QStringLiteral("no ComponentName for CstService");
      return;
    }
    intent.callObjectMethod(
        "putExtra",
        "(Ljava/lang/String;Ljava/lang/String;)Landroid/content/Intent;",
        QJniObject::fromString(QStringLiteral("text")).object<jstring>(),
        QJniObject::fromString(text).object<jstring>());
    QJniObject started =
        sdkInt() >= 26
            ? ctx.callObjectMethod(
                  "startForegroundService",
                  "(Landroid/content/Intent;)Landroid/content/ComponentName;",
                  intent.object<jobject>())
            : ctx.callObjectMethod(
                  "startService",
                  "(Landroid/content/Intent;)Landroid/content/ComponentName;",
                  intent.object<jobject>());
    if (!started.isValid())
      err = QStringLiteral("the phone refused the foreground service");
  });
  return err;
}

void releaseForeground() {
  if (qEnvironmentVariableIsSet("CST_APP_NO_SERVICE"))
    return;
  onGuiThread([&] {
    QJniObject ctx = appContext();
    if (!ctx.isValid())
      return;
    QJniObject intent = serviceIntent(
        ctx, QStringLiteral("xyz.whcself.cstagent.STOP"));
    if (intent.isValid())
      ctx.callMethod<jboolean>("stopService",
                               "(Landroid/content/Intent;)Z",
                               intent.object<jobject>());
  });
}

/* What the picker gave us -> a path the engine can open. A SAF URI is copied
 * into the app's own cache (the URI's grant covers the read; no permission is
 * involved), a plain path is left alone. */
QString materializeAttachment(const QString &pathOrUri, QString *err) {
  if (err)
    err->clear();
  if (pathOrUri.isEmpty())
    return QString();
  if (!pathOrUri.startsWith(QLatin1String("content://"))) {
    QString p = pathOrUri;
    if (p.startsWith(QLatin1String("file://")))
      p = p.mid(7);
    return p;
  }
  const QString dest = QStandardPaths::writableLocation(
                           QStandardPaths::CacheLocation) +
                       QStringLiteral("/picked");
  QString result, failure;
  onGuiThread([&] {
    QJniObject ctx = appContext();
    if (!ctx.isValid()) {
      failure = QStringLiteral("no Android context to copy the file with");
      return;
    }
    QJniObject out = QJniObject::callStaticObjectMethod(
        "xyz/whcself/cstagent/AttachFile", "materialize",
        "(Landroid/content/Context;Ljava/lang/String;Ljava/lang/String;)"
        "Ljava/lang/String;",
        ctx.object<jobject>(), QJniObject::fromString(pathOrUri).object<jstring>(),
        QJniObject::fromString(dest).object<jstring>());
    if (!out.isValid()) {
      failure = QStringLiteral("the phone could not hand that file over");
      return;
    }
    const QString s = out.toString();
    if (s.startsWith(QLatin1String("error: ")))
      failure = s.mid(7);
    else if (!s.isEmpty())
      result = s;
    /* "" means it was a path all along; the caller keeps what it had */
  });
  if (!failure.isEmpty()) {
    if (err)
      *err = failure;
    return QString();
  }
  return result.isEmpty() ? pathOrUri : result;
}

bool hasAllFilesAccess() {
  bool granted = true;
  onGuiThread([&] {
    QJniObject ctx = appContext();
    if (!ctx.isValid())
      return;
    granted = QJniObject::callStaticMethod<jboolean>(
        "xyz/whcself/cstagent/AttachFile", "hasAllFilesAccess",
        "(Landroid/content/Context;)Z", ctx.object<jobject>());
  });
  return granted;
}

QString requestAllFilesAccess() {
  if (qEnvironmentVariableIsSet("CST_APP_NO_PERM"))
    return QString(); /* a test run touches no settings */
  QString err;
  onGuiThread([&] {
    QJniObject ctx = appContext();
    if (!ctx.isValid())
      return;
    QJniObject out = QJniObject::callStaticObjectMethod(
        "xyz/whcself/cstagent/AttachFile", "requestAllFilesAccess",
        "(Landroid/content/Context;)Ljava/lang/String;",
        ctx.object<jobject>());
    if (out.isValid()) {
      const QString s = out.toString();
      if (!s.isEmpty())
        err = s;
    }
  });
  return err;
}

int platformRegisterAndroid(AgentCore *core) {
  if (!core)
    return 0;
  int n = 0;

  {
    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 notification in the phone's shade (what the user sees "
            "outside the app).",
            CST_TP_ASK, "notify", kAndroidOnly, notifyProbe);
    memcpy(g_notify.params, params, sizeof(params));
    g_notify.run_ex = notifyRun;
    g_notify.owner = "app:android";
    n += core->registerTool(&g_notify) ? 1 : 0;
  }
  {
    static const cst_tool_param_t params[CST_TOOL_MAX_PARAMS] = {
        {"max_bytes", "integer", 0, "cap on the returned text (default 65536)"},
        {nullptr, nullptr, 0, nullptr},
        {nullptr, nullptr, 0, nullptr},
        {nullptr, nullptr, 0, nullptr},
        {nullptr, nullptr, 0, nullptr},
        {nullptr, nullptr, 0, nullptr}};
    memset(&g_clip_read, 0, sizeof(g_clip_read));
    setMeta(&g_clip_read, "clipboard_read",
            "Read the text on the phone's clipboard — what the user copied "
            "outside the workspace. Returns UTF-8 text.",
            CST_TP_READ, "read", kAndroidOnly, clipboardProbe);
    memcpy(g_clip_read.params, params, sizeof(params));
    g_clip_read.run_ex = clipboardReadRun;
    g_clip_read.owner = "app:android";
    n += core->registerTool(&g_clip_read) ? 1 : 0;
  }
  {
    static const cst_tool_param_t params[CST_TOOL_MAX_PARAMS] = {
        {"text", "string", 1, "text to put on the clipboard"},
        {nullptr, nullptr, 0, nullptr},
        {nullptr, nullptr, 0, nullptr},
        {nullptr, nullptr, 0, nullptr},
        {nullptr, nullptr, 0, nullptr},
        {nullptr, nullptr, 0, nullptr}};
    memset(&g_clip_write, 0, sizeof(g_clip_write));
    setMeta(&g_clip_write, "clipboard_write",
            "Replace the phone's clipboard with text, so the user can paste it "
            "into another app. Overwrites what they had copied.",
            CST_TP_WRITE, "write", kAndroidOnly, clipboardProbe);
    memcpy(g_clip_write.params, params, sizeof(params));
    g_clip_write.run_ex = clipboardWriteRun;
    g_clip_write.owner = "app:android";
    n += core->registerTool(&g_clip_write) ? 1 : 0;
  }
  {
    static const cst_tool_param_t params[CST_TOOL_MAX_PARAMS] = {
        {"text", "string", 0, "text to share"},
        {"file", "string", 0, "workspace-relative file to share"},
        {"subject", "string", 0, "subject line of the shared item"},
        {nullptr, nullptr, 0, nullptr},
        {nullptr, nullptr, 0, nullptr},
        {nullptr, nullptr, 0, nullptr}};
    memset(&g_share, 0, sizeof(g_share));
    setMeta(&g_share, "share",
            "Hand text or a workspace file to the system share sheet, so the "
            "user can send it to another app.",
            CST_TP_ASK, "share", kAndroidOnly, shareProbe);
    memcpy(g_share.params, params, sizeof(params));
    g_share.run_ex = shareRun;
    g_share.owner = "app:android";
    n += core->registerTool(&g_share) ? 1 : 0;
  }
  return n;
}

}  // namespace app