/*
 * Copyright (C) 2018 "IoT.bzh"
 * Author Loïc Collignon <loic.collignon@iot.bzh>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <algorithm>
#include "ahl-api.hpp"
#include "ahl-binding.hpp"

/**
 * @brief Default constructor.
 */
ahl_binding_t::ahl_binding_t()
	: handle_{nullptr}
{
}

/**
 * @brief Creates static verbs.
 */
void ahl_binding_t::load_static_verbs()
{
	if (afb_api_add_verb(
			handle_,
			"get_roles",
			"Retrieve array of available audio roles",
			ahl_api_get_roles,
			nullptr,
			nullptr,
			AFB_SESSION_NONE_X2, 0))
	{
		throw std::runtime_error("Failed to add 'get_role' verb to the API.");
	}

	if (afb_api_add_verb(
			handle_,
			"activerole",
			"Controls the currently active role",
			ahl_api_activerole,
			nullptr,
			nullptr,
			AFB_SESSION_NONE_X2, 0))
	{
		throw std::runtime_error("Failed to add 'activerole' verb to the API.");
	}

	if (afb_api_add_verb(
			handle_,
			"subscribe",
			"Subscribe to \"volume_changed\" event",
			ahl_api_subscribe,
			nullptr,
			nullptr,
			AFB_SESSION_NONE_X2, 0))
	{
		throw std::runtime_error("Failed to add 'subscribe' verb to the API.");
	}

	if (afb_api_add_verb(
			handle_,
			"unsubscribe",
			"Unsubscribe to \"volume_changed\" event",
			ahl_api_unsubscribe,
			nullptr,
			nullptr,
			AFB_SESSION_NONE_X2, 0))
	{
		throw std::runtime_error("Failed to add 'unsubscribe' verb to the API.");
	}
}

/**
 * @brief Find all controller's configuration files.
 */
void ahl_binding_t::load_controller_configs()
{
	char* dir_list = getenv("CONTROL_CONFIG_PATH");
	if (!dir_list) dir_list = strdup(CONTROL_CONFIG_PATH);
	struct json_object* config_files = CtlConfigScan(dir_list, "policy");
	if (!config_files) throw std::runtime_error("No config files found!");

	// Only one file should be found this way, but read all just in case
	size_t config_files_count = json_object_array_length(config_files);
	for(int i = 0; i < config_files_count; ++i)
	{
		config_entry_t file {json_object_array_get_idx(config_files, i)};

		if(load_controller_config(file.filepath()) < 0)
		{
			std::stringstream ss;
			ss  << "Failed to load config file '"
				<< file.filename()
				<< "' from '"
				<< file.fullpath()
				<< "'!";
			throw std::runtime_error(ss.str());
		}
	}
}

/**
 * @brief Load a controller's configuration.
 * @param[in] path File to load.
 * @return Zero on success, non-zero otherwise.
 */
int ahl_binding_t::load_controller_config(const std::string& path)
{
	CtlConfigT* controller_config;

	controller_config = CtlLoadMetaData(handle_, path.c_str());
	if (!controller_config)
	{
		AFB_API_ERROR(handle_, "Failed to load controller from config file!");
		return -1;
	}

	static CtlSectionT controller_sections[] =
	{
		{.key = "plugins",  .uid = nullptr, .info = nullptr, .prefix = nullptr, .loadCB = PluginConfig,  .handle = nullptr, .actions = nullptr},
		{.key = "onload",   .uid = nullptr, .info = nullptr, .prefix = nullptr, .loadCB = OnloadConfig,  .handle = nullptr, .actions = nullptr},
		{.key = "controls", .uid = nullptr, .info = nullptr, .prefix = nullptr, .loadCB = ControlConfig, .handle = nullptr, .actions = nullptr},
		{.key = "events",   .uid = nullptr, .info = nullptr, .prefix = nullptr, .loadCB = EventConfig,   .handle = nullptr, .actions = nullptr},
		{.key = "roles",    .uid = nullptr, .info = nullptr, .prefix = nullptr, .loadCB = ahl_api_config_roles, .handle = nullptr, .actions = nullptr },
		{.key = nullptr,    .uid = nullptr, .info = nullptr, .prefix = nullptr, .loadCB = nullptr,       .handle = nullptr, .actions = nullptr}
	};

	CtlLoadSections(handle_, controller_config, controller_sections);

	return 0;
}

/**
 * @brief Update audio roles definition by binding to streams.
 * @return Status code, zero if success.
 */
int ahl_binding_t::update_streams()
{
	json_object* loaded = nullptr;
	size_t hals_count = 0, streams_count = 0;

	if (afb_api_call_sync(handle_, "4a-hal-manager", "loaded", json_object_new_object(), &loaded, nullptr, nullptr))
	{
		AFB_API_ERROR(handle_, "Failed to call 'loaded' verb on '4a-hal-manager' API!");
		if (loaded)
		{
			AFB_API_ERROR(handle_, "%s", json_object_to_json_string(loaded));
			json_object_put(loaded);
		}
		return -1;
	}

	if (!json_object_is_type(loaded, json_type_array))
	{
		AFB_API_ERROR(handle_, "Expected an array from '4a-hal-manager/loaded', but got something else!");
		json_object_put(loaded);
		return -1;
	}
	hals_count = json_object_array_length(loaded);

	for(int i = 0; i < hals_count; ++i)
	{
		json_object* info = nullptr;

		const char* halname = json_object_get_string(json_object_array_get_idx(loaded, i));
		AFB_API_DEBUG(handle_, "Found an active HAL: %s", halname);

		if (afb_api_call_sync(handle_, halname, "info", json_object_new_object(), &info, nullptr, nullptr))
		{
			AFB_API_ERROR(handle_, "Failed to call 'info' verb on '%s' API!", halname);
			if (info)
			{
				AFB_API_ERROR(handle_, "%s", json_object_to_json_string(info));
				json_object_put(info);
			}
			json_object_put(loaded);
			return -1;
		}

		json_object* streamsJ = nullptr;
		json_object_object_get_ex(info, "streams", &streamsJ);
		streams_count = json_object_array_length(streamsJ);
		for(int j = 0; j < streams_count; ++j)
		{
			json_object * nameJ = nullptr, * cardIdJ = nullptr;
			json_object * streamJ = json_object_array_get_idx(streamsJ, j);

			json_object_object_get_ex(streamJ, "name", &nameJ);
			json_object_object_get_ex(streamJ, "cardId", &cardIdJ);

			update_stream(
				halname,
				json_object_get_string(nameJ),
				json_object_get_string(cardIdJ)
			);
		}

		json_object_put(info);
	}
	json_object_put(loaded);

	return 0;
}

/**
 * @brief Update the stream info for audio roles.
 * @param[in] halname The hal on which the stream is.
 * @param[in] stream The name of the stream.
 * @param[in] deviceid The device ID to return when opening an audio role.
 */
void ahl_binding_t::update_stream(std::string halname, std::string stream, std::string deviceid)
{
	for(auto& r : roles_)
	{
		if(r.stream() == stream)
		{
			if (r.device_uri().size())
				AFB_API_WARNING(handle_, "Multiple stream with same name: '%s'.", stream.c_str());
			else
			{
				r.device_uri(deviceid);
				r.hal(halname);
			}
		}
	}
}

/**
 * @brief Create a verb based on a role.
 * @param[in] r Role to create a verb for.
 * @return Zero on success, non-zero otherwise.
 */
int ahl_binding_t::create_api_verb(role_t* r)
{
	AFB_API_NOTICE(handle_, "New audio role: %s", r->uid().c_str());

	if (afb_api_add_verb(
		handle_,
		r->uid().c_str(),
		r->description().c_str(),
		ahl_api_role,
		r,
		nullptr,
		AFB_SESSION_NONE_X2, 0))
	{
		AFB_API_ERROR(handle_, "Failed to add '%s' verb to the API.",
			r->uid().c_str());
		return -1;
	}

	return 0;
}

role_t* ahl_binding_t::get_active_role()
{
	role_t* active = nullptr;
	for(auto& r : roles_)
	{
		if (r.opened() && (active == nullptr || r.priority() > active->priority()))
			active = &r;
	}

	return active;
}

/**
 * @brief Get the singleton instance.
 * @return The unique instance.
 */
ahl_binding_t& ahl_binding_t::instance()
{
	static ahl_binding_t s;
	return s;
}

/**
 * @brief Get the api handle.
 * @return The api handle.
 */
afb_api_t ahl_binding_t::handle() const
{
	return handle_;
}

/**
 * @brief Get the role list.
 * @return A vector of roles.
 */
const std::vector<role_t> ahl_binding_t::roles() const
{
	return roles_;
}


/**
 * @brief This method is called during the pre-init phase of loading the binding.
 * @param[in] handle Handle to the api.
 * @return Status code, zero if success.
 */
int ahl_binding_t::preinit(afb_api_t handle)
{
	handle_ = handle;

	try
	{
		load_static_verbs();
		load_controller_configs();

		if (afb_api_on_event(handle_, ahl_api_on_event))
			throw std::runtime_error("Failed to register event handler callback.");

		if (afb_api_on_init(handle_, ahl_api_init))
			throw std::runtime_error("Failed to register init handler callback.");
	}
	catch(std::exception& e)
	{
		AFB_API_ERROR(handle, "%s", e.what());
		return -1;
	}

	return 0;
}

/**
 * @brief Initialize the API.
 */
int ahl_binding_t::init()
{
	using namespace std::placeholders;

	if (afb_api_require_api(handle_, HAL_MGR_API, 1))
	{
		AFB_API_ERROR(handle_, "Failed to require '%s' API!", HAL_MGR_API);
		return -1;
	}
	AFB_API_NOTICE(handle_, "Required '%s' API found!", HAL_MGR_API);

	afb_api_seal(handle_);
	AFB_API_NOTICE(handle_, "API is now sealed!");

	volume_changed_ = afb_api_make_event(handle_, "volume_changed");
	if(!afb_event_is_valid(volume_changed_))
	{
		AFB_API_ERROR(handle_, "Failed to create the \"volume_changed\" event!");
		return -2;
	}

	if (update_streams()) return -1;
	return 0;
}

/**
 * @brief Called when an event is received by this binding.
 * @param[in] name Event's name.
 * @param[in] arg Event's argument.
 */
void ahl_binding_t::event(std::string name, json_object* arg)
{
	AFB_API_DEBUG(handle_, "Event '%s' received with the following arg: %s", name.c_str(), json_object_to_json_string(arg));
}

/**
 * @brief Emit the 'volume-changed' event.
 * @param[in] role Role's uid.
 * @param[in] volume New volume.
 * @return Zero on success, non-zero otherwise.
 */
int ahl_binding_t::emit_volume_changed(const std::string& role, int volume)
{
	json_object* data = json_object_new_object();
	json_object_object_add(data, "role", json_object_new_string(role.c_str()));
	json_object_object_add(data, "volume", json_object_new_int(volume));

	bool active = false;
	role_t* activerole = get_active_role();
	if (activerole && activerole->uid() == role)
		active = true;

	json_object_object_add(data, "active", json_object_new_boolean(active));

	return afb_event_push(volume_changed_, data);
}

/**
 * @brief Parse the role configuration section.
 * @param[in] o Role's section.
 * @return Zero on success, non-zero otherwise.
 */
int ahl_binding_t::parse_roles_config(json_object* o)
{
	assert(o != nullptr);
	assert(json_object_is_type(o, json_type_array));

	if (roles_.size()) return 0; // Roles already added, ignore.

	size_t count = json_object_array_length(o);
	roles_.reserve(count);
	for(int i = 0; i < count; ++i)
	{
		json_object* jr = json_object_array_get_idx(o, i);
		assert(jr != nullptr);

		roles_.push_back(role_t(jr));
		role_t& r = roles_[roles_.size() - 1];
		if(create_api_verb(&r))
			return -1;
	}

	return 0;
}

// ---------- Callbacks to verbs ----------

/**
 * @brief Get the roles list.
 * @param[in] req Request to answer.
 */
void ahl_binding_t::get_roles(afb_req_t req) const
{
	json_bool verbose = FALSE;
	json_object* arg = afb_req_json(req);
	json_object* jverbose;
	if (arg != nullptr)
	{
		json_bool ret = json_object_object_get_ex(arg, "verbose", &jverbose);
		if (ret) verbose = json_object_get_boolean(jverbose);
	}

	json_object* result = json_object_new_array();
	for(const auto& r : roles_)
	{
		if (verbose == TRUE || r.device_uri().size())
			json_object_array_add(result, json_object_new_string(r.uid().c_str()));
	}
	afb_req_success(req, result, nullptr);
}

/**
 * @brief Controls the currently active role.
 * @param[in] req Request to answer.
 */
void ahl_binding_t::activerole(afb_req_t req)
{
	role_t* role = get_active_role();
	if (!role) afb_req_fail(req, "No active role!", nullptr);
	else role->invoke(req);
}

/**
 * @brief Subscribe to events.
 * @param[in] req Request to answer.
 */
void ahl_binding_t::subscribe(afb_req_t req) const
{
    if (afb_req_subscribe(req, volume_changed_))
        afb_req_fail(req, "Failed to subscribe to \"volume_changed\" event!", nullptr);
    else
        afb_req_success(req, nullptr, "Subscribed to \"volume_changed\" event!");
}
/**
 * @brief Unsubscribe to events.
 * @param[in] req Request to answer.
 */
void ahl_binding_t::unsubscribe(afb_req_t req) const
{
    if (afb_req_unsubscribe(req, volume_changed_))
        afb_req_fail(req, "Failed to unsubscribe from \"volume_changed\" event!", nullptr);
    else
        afb_req_success(req, nullptr, "Unsubscribed from \"volume_changed\" event!");
}