#include "components/controller.hpp"

#include <csignal>
#include <utility>

#include "components/bar.hpp"
#include "components/builder.hpp"
#include "components/config.hpp"
#include "components/eventloop.hpp"
#include "components/logger.hpp"
#include "components/types.hpp"
#include "events/signal.hpp"
#include "events/signal_emitter.hpp"
#include "modules/meta/base.hpp"
#include "modules/meta/event_handler.hpp"
#include "modules/meta/factory.hpp"
#include "utils/actions.hpp"
#include "utils/inotify.hpp"
#include "utils/process.hpp"
#include "utils/string.hpp"
#include "utils/time.hpp"
#include "x11/connection.hpp"
#include "x11/extensions/all.hpp"

POLYBAR_NS

using namespace eventloop;

/**
 * Build controller instance
 */
controller::make_type controller::make(bool has_ipc, loop& loop) {
  return std::make_unique<controller>(
      connection::make(), signal_emitter::make(), logger::make(), config::make(), has_ipc, loop);
}

/**
 * Construct controller
 */
controller::controller(
    connection& conn, signal_emitter& emitter, const logger& logger, const config& config, bool has_ipc, loop& loop)
    : m_connection(conn)
    , m_sig(emitter)
    , m_log(logger)
    , m_conf(config)
    , m_loop(loop)
    , m_bar(bar::make(m_loop))
    , m_has_ipc(has_ipc) {
  m_conf.ignore_key("settings", "throttle-input-for");
  m_conf.ignore_key("settings", "throttle-output");
  m_conf.ignore_key("settings", "throttle-output-for");
  m_conf.ignore_key("settings", "eventqueue-swallow");
  m_conf.ignore_key("settings", "eventqueue-swallow-time");

  m_log.trace("controller: Setup user-defined modules");
  size_t created_modules{0};
  created_modules += setup_modules(alignment::LEFT);
  created_modules += setup_modules(alignment::CENTER);
  created_modules += setup_modules(alignment::RIGHT);

  if (!created_modules) {
    throw application_error("No modules created");
  }

  m_log.notice("Loaded %zd modules", created_modules);
}

/**
 * Deconstruct controller
 */
controller::~controller() {
  m_log.trace("controller: Detach signal receiver");
  m_sig.detach(this);

  m_log.trace("controller: Stop modules");
  for (auto&& module : m_modules) {
    auto module_name = module->name();
    auto cleanup_ms = time_util::measure([&module] {
      module->stop();
      module->join();
      module.reset();
    });
    m_log.info("Deconstruction of %s took %lu ms.", module_name, cleanup_ms);
  }
}

/**
 * Run the main loop
 */
bool controller::run(bool writeback, string snapshot_dst, bool confwatch) {
  m_log.info("Starting application");
  m_log.trace("controller: Main thread id = %i", concurrency_util::thread_id(this_thread::get_id()));

  assert(!m_connection.connection_has_error());

  m_writeback = writeback;
  m_snapshot_dst = move(snapshot_dst);

  m_sig.attach(this);

  size_t started_modules{0};
  for (const auto& module : m_modules) {
    auto evt_handler = dynamic_cast<event_handler_interface*>(&*module);

    if (evt_handler != nullptr) {
      evt_handler->connect(m_connection);
    }

    try {
      m_log.info("Starting %s", module->name());
      module->start();
      started_modules++;
    } catch (const application_error& err) {
      m_log.err("Failed to start '%s' (reason: %s)", module->name(), err.what());
    }
  }

  if (!started_modules) {
    throw application_error("No modules started");
  }

  m_connection.flush();

  read_events(confwatch);

  m_log.notice("Termination signal received, shutting down...");

  return !m_reload;
}

/**
 * Enqueue input data
 */
void controller::trigger_action(string&& input_data) {
  std::unique_lock<std::mutex> guard(m_notification_mutex);
  m_log.trace("controller: Queueing input event '%s'", input_data);
  m_notifications.inputdata.push(std::move(input_data));
  trigger_notification();
}

void controller::trigger_quit(bool reload) {
  std::unique_lock<std::mutex> guard(m_notification_mutex);
  m_notifications.quit = true;
  m_notifications.reload = m_notifications.reload || reload;
  trigger_notification();
}

void controller::trigger_update(bool force) {
  std::unique_lock<std::mutex> guard(m_notification_mutex);
  m_notifications.update = true;
  m_notifications.force_update = m_notifications.force_update || force;

  trigger_notification();
}

void controller::trigger_notification() {
  m_notifier->send();
}

void controller::stop(bool reload) {
  update_reload(reload);
  m_loop.stop();
}

void controller::conn_cb() {
  int xcb_error = m_connection.connection_has_error();
  if ((xcb_error = m_connection.connection_has_error()) != 0) {
    m_log.err("X connection error, terminating... (what: %s)", m_connection.error_str(xcb_error));
    stop(false);
    return;
  }

  shared_ptr<xcb_generic_event_t> evt{};
  while ((evt = m_connection.poll_for_event()) != nullptr) {
    try {
      m_connection.dispatch_event(evt);
    } catch (xpp::connection_error& err) {
      m_log.err("X connection error, terminating... (what: %s)", m_connection.error_str(err.code()));
      stop(false);
    } catch (const exception& err) {
      // IDs for events are defined in xproto.h
      m_log.err("Error in X event loop while handling event %d: %s", evt->response_type, err.what());
    }
  }

  if ((xcb_error = m_connection.connection_has_error()) != 0) {
    m_log.err("X connection error, terminating... (what: %s)", m_connection.error_str(xcb_error));
    stop(false);
    return;
  }
}

void controller::signal_handler(int signum) {
  m_log.notice("Received signal(%d): %s", signum, strsignal(signum));
  stop(signum == SIGUSR1);
}

void controller::create_config_watcher(const string& filename) {
  auto fs_event_handle = m_loop.handle<FSEventHandle>();
  fs_event_handle->start(
      filename, 0, [this](const auto& e) { confwatch_handler(e.path); },
      [this, &handle = *fs_event_handle](const auto& e) {
        m_log.err("libuv error while watching included file for changes: %s", uv_strerror(e.status));
        handle.close();
      });
}

void controller::confwatch_handler(const char* filename) {
  m_log.notice("Watched config file changed %s", filename);
  stop(true);
}

void controller::notifier_handler() {
  notifications_t data{};

  {
    std::unique_lock<std::mutex> guard(m_notification_mutex);
    std::swap(m_notifications, data);
  }

  if (data.quit) {
    stop(data.reload);
    return;
  }

  while (!data.inputdata.empty()) {
    auto inputdata = data.inputdata.front();
    data.inputdata.pop();
    m_log.trace("controller: Dequeueing inputdata: '%s'", inputdata);
    process_inputdata(std::move(inputdata));
  }

  if (data.update) {
    process_update(data.force_update);
  }
}

void controller::screenshot_handler() {
  m_sig.emit(signals::ui::request_snapshot{move(m_snapshot_dst)});
  trigger_update(true);
}

/**
 * Read events from configured file descriptors
 */
void controller::read_events(bool confwatch) {
  m_log.info("Entering event loop (thread-id=%lu)", this_thread::get_id());

  try {
    auto x_poll_handle = m_loop.handle<PollHandle>(m_connection.get_file_descriptor());
    x_poll_handle->start(
        UV_READABLE, [this](const auto&) { conn_cb(); },
        [this](const auto& e) {
          m_log.err("libuv error while polling X connection: "s + uv_strerror(e.status));
          stop(false);
        });

    auto x_prepare_handle = m_loop.handle<PrepareHandle>();
    x_prepare_handle->start([this]() {
      /*
       * We have to also handle events in the prepare handle (which runs right
       * before polling for IO) to process any already queued X events which
       * wouldn't trigger the uv_poll handle.
       */
      conn_cb();
      m_connection.flush();
    });

    for (auto s : {SIGINT, SIGQUIT, SIGTERM, SIGUSR1, SIGALRM}) {
      auto signal_handle = m_loop.handle<SignalHandle>();
      signal_handle->start(s, [this](const auto& e) { signal_handler(e.signum); });
    }

    if (confwatch) {
      create_config_watcher(m_conf.filepath());
      // also watch the include-files for changes
      for (auto& module_path : m_conf.get_included_files()) {
        create_config_watcher(module_path);
      }
    }

    if (!m_snapshot_dst.empty()) {
      // Trigger a single screenshot after 3 seconds
      auto timer_handle = m_loop.handle<TimerHandle>();
      timer_handle->start(3000, 0, [this]() { screenshot_handler(); });
    }

    if (!m_writeback) {
      m_bar->start(m_tray_module_name);
    }

    /*
     * Immediately trigger and update so that the bar displays something.
     */
    trigger_update(true);

    m_loop.run();
  } catch (const exception& err) {
    m_log.err("Fatal Error in eventloop: %s", err.what());
    stop(false);
  }

  m_log.info("Eventloop finished");
}

/**
 * Tries to match the given command to a legacy action string and sends the
 * appropriate new action (and data) to the right module if possible.
 *
 * @returns true iff the given command matches a legacy action string and was
 *          successfully forwarded to a module
 */
bool controller::try_forward_legacy_action(const string& cmd) {
  /*
   * Maps legacy action names to a module type and the new action name in that module.
   *
   * We try to match the old action name as a prefix, and everything after it will also be added to the end of the new
   * action string (for example "mpdseek+5" will be redirected to "seek.+5" in the first mpd module).
   *
   * The action will be delivered to the first module of that type so that it is consistent with existing behavior.
   * If the module does not support the action or no matching module is found, the command is forwarded to the shell.
   *
   * TODO Remove when deprecated action names are removed
   */
// clang-format off
#define A_MAP(old, module_name, event) {old, {string(module_name::TYPE), string(module_name::event)}}

  static const std::unordered_map<string, std::pair<string, const string>> legacy_actions{
    A_MAP("datetoggle", date_module, EVENT_TOGGLE),
#if ENABLE_ALSA
    A_MAP("volup", alsa_module, EVENT_INC),
    A_MAP("voldown", alsa_module, EVENT_DEC),
    A_MAP("volmute", alsa_module, EVENT_TOGGLE),
#endif
#if ENABLE_PULSEAUDIO
    A_MAP("pa_volup", pulseaudio_module, EVENT_INC),
    A_MAP("pa_voldown", pulseaudio_module, EVENT_DEC),
    A_MAP("pa_volmute", pulseaudio_module, EVENT_TOGGLE),
#endif
    A_MAP("xbacklight+", xbacklight_module, EVENT_INC),
    A_MAP("xbacklight-", xbacklight_module, EVENT_DEC),
    A_MAP("backlight+", backlight_module, EVENT_INC),
    A_MAP("backlight-", backlight_module, EVENT_DEC),
#if ENABLE_XKEYBOARD
    A_MAP("xkeyboard/switch", xkeyboard_module, EVENT_SWITCH),
#endif
#if ENABLE_MPD
    A_MAP("mpdplay", mpd_module, EVENT_PLAY),
    A_MAP("mpdpause", mpd_module, EVENT_PAUSE),
    A_MAP("mpdstop", mpd_module, EVENT_STOP),
    A_MAP("mpdprev", mpd_module, EVENT_PREV),
    A_MAP("mpdnext", mpd_module, EVENT_NEXT),
    A_MAP("mpdrepeat", mpd_module, EVENT_REPEAT),
    A_MAP("mpdsingle", mpd_module, EVENT_SINGLE),
    A_MAP("mpdrandom", mpd_module, EVENT_RANDOM),
    A_MAP("mpdconsume", mpd_module, EVENT_CONSUME),
    // Has data
    A_MAP("mpdseek", mpd_module, EVENT_SEEK),
#endif
    // Has data
    A_MAP("xworkspaces-focus=", xworkspaces_module, EVENT_FOCUS),
    A_MAP("xworkspaces-next", xworkspaces_module, EVENT_NEXT),
    A_MAP("xworkspaces-prev", xworkspaces_module, EVENT_PREV),
    // Has data
    A_MAP("bspwm-deskfocus", bspwm_module, EVENT_FOCUS),
    A_MAP("bspwm-desknext", bspwm_module, EVENT_NEXT),
    A_MAP("bspwm-deskprev", bspwm_module, EVENT_PREV),
#if ENABLE_I3
    // Has data
    A_MAP("i3wm-wsfocus-", i3_module, EVENT_FOCUS),
    A_MAP("i3wm-wsnext", i3_module, EVENT_NEXT),
    A_MAP("i3wm-wsprev", i3_module, EVENT_PREV),
#endif
    // Has data
    A_MAP("menu-open-", menu_module, EVENT_OPEN),
    A_MAP("menu-close", menu_module, EVENT_CLOSE),
  };
#undef A_MAP
  // clang-format on

  // Check if any key in the map is a prefix for the `cmd`
  for (const auto& entry : legacy_actions) {
    const auto& key = entry.first;
    if (cmd.compare(0, key.length(), key) == 0) {
      string type = entry.second.first;
      auto data = cmd.substr(key.length());
      string action = entry.second.second;

      // Search for the first module that matches the type for this legacy action
      for (auto&& module : m_modules) {
        if (module->type() == type) {
          auto module_name = module->name_raw();
          if (data.empty()) {
            m_log.warn("The action '%s' is deprecated, use '#%s.%s' instead!", cmd, module_name, action);
          } else {
            m_log.warn("The action '%s' is deprecated, use '#%s.%s.%s' instead!", cmd, module_name, action, data);
          }
          m_log.warn("Consult the 'Actions' page in the polybar documentation for more information.");
          m_log.info(
              "Forwarding legacy action '%s' to module '%s' as '%s' with data '%s'", cmd, module_name, action, data);
          if (!module->input(action, data)) {
            m_log.err("Failed to forward deprecated action to %s module", type);
            // Forward to shell if the module cannot accept the action to not break existing behavior.
            return false;
          }
          // Only deliver to the first matching module.
          return true;
        }
      }
    }
  }

  /*
   * If we couldn't find any matching legacy action, we return false and let
   * the command be forwarded to the shell
   */
  return false;
}

bool controller::forward_action(const actions_util::action& action_triple) {
  string module_name = std::get<0>(action_triple);
  string action = std::get<1>(action_triple);
  string data = std::get<2>(action_triple);

  m_log.info("Forwarding action to modules (module: '%s', action: '%s', data: '%s')", module_name, action, data);

  int num_delivered = 0;

  // Forwards the action to all modules that match the name
  for (auto&& module : m_modules) {
    if (module->name_raw() == module_name) {
      if (!module->input(action, data)) {
        m_log.err("The '%s' module does not support the '%s' action.", module_name, action);
      }

      num_delivered++;
    }
  }

  if (num_delivered == 0) {
    m_log.err("Could not forward action to module: No module named '%s' (action: '%s', data: '%s')", module_name,
        action, data);
  } else {
    m_log.info("Delivered action to %d module%s", num_delivered, num_delivered > 1 ? "s" : "");
  }
  return true;
}

/**
 * Process stored input data
 */
void controller::process_inputdata(string&& cmd) {
  m_log.trace("controller: Processing inputdata: %s", cmd);

  // Every command that starts with '#' is considered an action string.
  if (cmd.front() == '#') {
    try {
      this->forward_action(actions_util::parse_action_string(cmd));
    } catch (runtime_error& e) {
      m_log.err("Invalid action string (action: %s, reason: %s)", cmd, e.what());
    }

    return;
  }

  if (this->try_forward_legacy_action(cmd)) {
    return;
  }

  try {
    // Run input as command if it's not an input for a module
    m_log.info("Forwarding command to shell... (input: %s)", cmd);
    m_log.info("Executing shell command: %s", cmd);
    process_util::fork_detached([cmd] { process_util::exec_sh(cmd.c_str()); });
    process_update(true);
  } catch (const application_error& err) {
    m_log.err("controller: Error while forwarding input to shell -> %s", err.what());
  }
}

/**
 * Process eventqueue update event
 */
bool controller::process_update(bool force) {
  const bar_settings& bar{m_bar->settings()};
  string contents;
  string padding_left = builder::get_spacing_format_string(bar.padding.left);
  string padding_right = builder::get_spacing_format_string(bar.padding.right);
  string margin_left = builder::get_spacing_format_string(bar.module_margin.left);
  string margin_right = builder::get_spacing_format_string(bar.module_margin.right);

  builder build{bar};
  build.node(bar.separator);
  string separator{build.flush()};

  for (const auto& block : m_blocks) {
    string block_contents;
    bool is_left = false;
    bool is_center = false;
    bool is_right = false;
    bool is_first = true;

    if (block.first == alignment::LEFT) {
      is_left = true;
    } else if (block.first == alignment::CENTER) {
      is_center = true;
    } else if (block.first == alignment::RIGHT) {
      is_right = true;
    }

    for (const auto& module : block.second) {
      if (!module->running() || !module->visible()) {
        continue;
      }

      string module_contents;

      try {
        module_contents = module->contents();
      } catch (const exception& err) {
        m_log.err("Failed to get contents for \"%s\" (err: %s)", module->name(), err.what());
      }

      if (module_contents.empty()) {
        continue;
      }

      if (!block_contents.empty() && !margin_right.empty()) {
        block_contents += margin_right;
      }

      if (!block_contents.empty() && !separator.empty()) {
        block_contents += separator;
      }

      if (!block_contents.empty() && !margin_left.empty() && !(is_left && is_first)) {
        block_contents += margin_left;
      }

      block_contents.reserve(module_contents.size());
      block_contents += module_contents;

      is_first = false;
    }

    if (block_contents.empty()) {
      continue;
    } else if (is_left) {
      contents += "%{l}";
      contents += padding_left;
    } else if (is_center) {
      contents += "%{c}";
    } else if (is_right) {
      contents += "%{r}";
      block_contents += padding_right;
    }

    contents += block_contents;
  }

  try {
    if (!m_writeback) {
      m_bar->parse(move(contents), force);
    } else {
      std::cout << contents << std::endl;
    }
  } catch (const exception& err) {
    m_log.err("Failed to update bar contents (reason: %s)", err.what());
  }

  return true;
}

void controller::update_reload(bool reload) {
  m_reload = m_reload || reload;
}

/**
 * Creates module instances for all the modules in the given alignment block
 */
size_t controller::setup_modules(alignment align) {
  string key;

  switch (align) {
    case alignment::LEFT:
      key = "modules-left";
      break;

    case alignment::CENTER:
      key = "modules-center";
      break;

    case alignment::RIGHT:
      key = "modules-right";
      break;

    case alignment::NONE:
      m_log.err("controller: Tried to setup modules for alignment NONE");
      break;
  }

  string configured_modules;
  if (!key.empty()) {
    configured_modules = m_conf.get(m_conf.section(), key, ""s);
  }

  for (auto& module_name : string_util::split(configured_modules, ' ')) {
    if (module_name.empty()) {
      continue;
    }

    try {
      auto type = m_conf.get("module/" + module_name, "type");

      if (type == tray_module::TYPE) {
        if (!m_tray_module_name.empty()) {
          throw module_error("Multiple trays defined. Using tray `" + m_tray_module_name + "`");
        }
        m_tray_module_name = module_name;
      }

      if (type == ipc_module::TYPE && !m_has_ipc) {
        throw application_error("Inter-process messaging needs to be enabled");
      }

      m_log.notice("Loading module '%s' of type '%s'", module_name, type);
      auto ptr = make_module(move(type), m_bar->settings(), module_name, m_log);
      module_t module = shared_ptr<modules::module_interface>(ptr);
      ptr = nullptr;

      m_modules.push_back(module);
      m_blocks[align].push_back(module);
    } catch (const std::exception& err) {
      m_log.err("Disabling module \"%s\" (reason: %s)", module_name, err.what());
    }
  }

  return m_blocks[align].size();
}

/**
 * Process broadcast events
 */
bool controller::on(const signals::eventqueue::notify_change&) {
  trigger_update(false);
  return true;
}

/**
 * Process forced broadcast events
 */
bool controller::on(const signals::eventqueue::notify_forcechange&) {
  trigger_update(true);
  return true;
}

/**
 * Process eventqueue reload event
 */
bool controller::on(const signals::eventqueue::exit_reload&) {
  trigger_quit(true);
  return true;
}

/**
 * Process eventqueue check event
 */
bool controller::on(const signals::eventqueue::check_state&) {
  for (const auto& module : m_modules) {
    if (module->running()) {
      return true;
    }
  }
  m_log.warn("No running modules...");
  trigger_quit(false);
  return true;
}

/**
 * Process ui button press event
 */
bool controller::on(const signals::ui::button_press& evt) {
  string input{evt.cast()};

  if (input.empty()) {
    m_log.err("Cannot enqueue empty input");
    return false;
  }

  trigger_action(move(input));
  return true;
}

/**
 * Process ipc action messages
 */
bool controller::on(const signals::ipc::action& evt) {
  string action{evt.cast()};

  if (action.empty()) {
    m_log.err("Cannot enqueue empty ipc action");
    return false;
  }

  m_log.info("Enqueuing ipc action: %s", action);
  trigger_action(move(action));
  return true;
}

/**
 * Process ipc command messages
 */
bool controller::on(const signals::ipc::command& evt) {
  string command{evt.cast()};

  if (command.empty()) {
    return false;
  }

  if (command == "quit") {
    trigger_quit(false);
  } else if (command == "restart") {
    trigger_quit(true);
  } else if (command == "hide") {
    m_bar->hide();
  } else if (command == "show") {
    m_bar->show();
  } else if (command == "toggle") {
    m_bar->toggle();
  } else {
    m_log.warn("\"%s\" is not a valid ipc command", command);
    return false;
  }

  return true;
}

/**
 * Process ipc hook messages
 */
bool controller::on(const signals::ipc::hook& evt) {
  string hook{evt.cast()};

  for (const auto& module : m_modules) {
    if (!module->running()) {
      continue;
    }
    auto ipc = std::dynamic_pointer_cast<ipc_module>(module);
    if (ipc != nullptr) {
      ipc->on_message(hook);
    }
  }

  return true;
}

bool controller::on(const signals::ui::update_background&) {
  trigger_update(true);
  return false;
}

POLYBAR_NS_END