/*
 * .============.
 * // M A K E / \
 * // C++ DEV / \
 * // E A S Y / \/ \
 * ++ ----------. \/\ .
 * \\ \ \ /\ /
 * \\ \ \ /
 * \\ \ \ /
 * -============'
 *
 * Copyright (c) 2018 Hevake and contributors, all rights reserved.
 *
 * This file is part of cpp-tbox (https://github.com/cpp-main/cpp-tbox)
 * Use of this source code is governed by MIT license that can be found
 * in the LICENSE file in the root of the source tree. All contributing
 * project authors may be found in the CONTRIBUTORS.md file in the root
 * of the source tree.
 */
#include "action_executor.h"

#include <algorithm>
#include <tbox/base/assert.h>
#include "action.h"

namespace tbox {
namespace flow {

ActionExecutor::ActionExecutor() { }

ActionExecutor::~ActionExecutor() {
 TBOX_ASSERT(cb_level_ == 0);
 for (auto &action_deque : action_deque_array_) {
 for (auto item : action_deque)
 delete item.action;
 action_deque.clear();
 }
}

ActionExecutor::ActionId ActionExecutor::append(Action *action, int prio) {
 TBOX_ASSERT(0 <= prio && prio <= 2);
 TBOX_ASSERT(action != nullptr);

 Item item = {
 .id = allocActionId(),
 .action = action
 };
 action_deque_array_.at(prio).push_back(item);
 action->setFinishCallback([this](bool, const Action::Reason &, const Action::Trace &) { schedule(); });
 action->vars().setParent(&vars_);
 schedule();
 return item.id;
}

ActionExecutor::ActionId ActionExecutor::current() const {
 if (curr_action_deque_index_ == -1)
 return -1;

 auto &action_deque = action_deque_array_.at(curr_action_deque_index_);
 return action_deque.front().id;
}

bool ActionExecutor::cancelCurrent() {
 if (curr_action_deque_index_ == -1)
 return false;

 auto &action_deque = action_deque_array_.at(curr_action_deque_index_);
 auto item = action_deque.front();
 item.action->stop();
 delete item.action;
 action_deque.pop_front();
 schedule();
 return true;
}

bool ActionExecutor::cancel(ActionId action_id) {
 TBOX_ASSERT(action_id > 0);

 for (auto &action_deque : action_deque_array_) {
 auto iter = std::find_if(action_deque.begin(), action_deque.end(),
 [action_id] (const Item &item) { return item.id == action_id; }
 );

 if (iter != action_deque.end()) {
 delete iter->action;
 action_deque.erase(iter);
 schedule();
 return true;
 }
 }
 return false;
}

void ActionExecutor::cancelAll() {
 for (auto &action_deque : action_deque_array_) {
 if (!action_deque.empty()) {
 auto action_item = action_deque.front();
 action_item.action->stop();
 }
 }
}

ActionExecutor::ActionId ActionExecutor::allocActionId() { return ++action_id_alloc_counter_; }

void ActionExecutor::schedule() {
 TBOX_ASSERT(cb_level_ == 0);

 while (true) {
 //! 找出优先级最高,且不为空的队列
 int ready_deque_index = -1;
 for (int i = 0; i < 3; ++i) {
 if (!action_deque_array_.at(i).empty()) {
 ready_deque_index = i;
 break;
 }
 }

 //! 如果所有的队列都是空的,那么就直接退出
 if (ready_deque_index == -1) {
 ++cb_level_;
 if (all_finished_cb_)
 all_finished_cb_();
 --cb_level_;
 return;
 }

 //! 如果高优先级的队列比当前队列优先级还高,则要先暂停当前队列头部的动作
 if (curr_action_deque_index_ != -1 &&
 ready_deque_index < curr_action_deque_index_) {
 action_deque_array_.at(curr_action_deque_index_).front().action->pause();
 }

 auto &ready_deque = action_deque_array_.at(ready_deque_index);
 while (!ready_deque.empty()) {
 auto item = ready_deque.front();
 //! 没有启动的要启动
 if (item.action->state() == Action::State::kIdle) {
 if (item.action->start()) {
 curr_action_deque_index_ = ready_deque_index;
 ++cb_level_;
 if (action_started_cb_)
 action_started_cb_(item.id);
 --cb_level_;
 } else {
 ready_deque.pop_front();
 delete item.action;
 curr_action_deque_index_ = -1;
 ++cb_level_;
 if (action_finished_cb_)
 action_finished_cb_(item.id);
 --cb_level_;
 }

 //! 被暂停了的,要恢复
 } else if (item.action->state() == Action::State::kPause) {
 curr_action_deque_index_ = ready_deque_index;
 item.action->resume();

 //! 已完成了的,要删除
 } else if (item.action->state() == Action::State::kFinished ||
 item.action->state() == Action::State::kStoped) {
 ready_deque.pop_front();
 delete item.action;
 curr_action_deque_index_ = -1;
 ++cb_level_;
 if (action_finished_cb_)
 action_finished_cb_(item.id);
 --cb_level_;

 //! 其它状态:运行中,不需要处理
 } else {
 return;
 }
 }
 }
}

}
}