#include "mission/mission_scheduler.hpp"

#include "util/id_util.hpp"

#include <chrono>

namespace lm {

MissionScheduler::MissionScheduler(MissionStore& store, EnqueueFn enqueue_fn)
    : store_(store), enqueue_fn_(std::move(enqueue_fn))
{
  worker_ = std::thread([this] { workerLoop(); });
}

MissionScheduler::~MissionScheduler()
{
  stop_ = true;
  if (worker_.joinable())
    worker_.join();
}

bool MissionScheduler::queueSchedule(const nlohmann::json& schedule, std::string& err)
{
  nlohmann::json req = {{"mission_id", schedule.value("mission_id", "")},
                        {"priority", schedule.value("priority", 0)},
                        {"robot_id", schedule.value("robot_id", "default")},
                        {"source", "fleet:" + schedule.value("name", "schedule")}};
  if (!enqueue_fn_(req, err))
    return false;
  markQueued(schedule.value("id", ""));
  return true;
}

void MissionScheduler::markQueued(const std::string& id)
{
  if (id.empty())
    return;
  nlohmann::json patch = {{"last_queued_at", IdUtil::nowIso8601()}};
  std::string err;
  store_.updateSchedule(id, patch, err);
}

bool MissionScheduler::runScheduleNow(const std::string& id, std::string& err)
{
  const auto schedule = store_.findSchedule(id);
  if (!schedule)
  {
    err = "schedule not found";
    return false;
  }
  if (!schedule->value("enabled", true))
  {
    err = "schedule is disabled";
    return false;
  }
  return queueSchedule(*schedule, err);
}

void MissionScheduler::workerLoop()
{
  while (!stop_)
  {
    const auto schedules = store_.listSchedules();
    const std::string now = IdUtil::nowIso8601();
    for (const auto& schedule : schedules)
    {
      if (!schedule.is_object() || !schedule.value("enabled", true))
        continue;
      const std::string mode = schedule.value("start_mode", "asap");
      if (mode == "asap")
      {
        if (schedule.contains("last_queued_at") && !schedule["last_queued_at"].is_null())
          continue;
        std::string err;
        queueSchedule(schedule, err);
        continue;
      }
      if (mode == "scheduled")
      {
        if (!schedule.contains("start_at") || schedule["start_at"].is_null())
          continue;
        const std::string start_at = schedule["start_at"].get<std::string>();
        if (start_at > now)
          continue;
        if (schedule.contains("last_queued_at") && !schedule["last_queued_at"].is_null())
          continue;
        std::string err;
        queueSchedule(schedule, err);
      }
    }
    for (int i = 0; i < 20 && !stop_; ++i)
      std::this_thread::sleep_for(std::chrono::milliseconds(100));
  }
}

}  // namespace lm