#include <daggy/Serialization.hpp>
#include <daggy/Utilities.hpp>
#include <daggy/executors/task/DaggyRunnerTaskExecutor.hpp>
#include <daggy/executors/task/ForkingTaskExecutor.hpp>
#include <iomanip>

using namespace daggy::executors::task;
using namespace daggy::executors::task::daggy_runner;
using namespace daggy;

namespace daggy::executors::task::daggy_runner {
  std::string capacityToJSON(const Capacity &cap)
  {
    return R"({ "cores": )" + std::to_string(cap.cores) + R"(, "memoryMB": )" +
           std::to_string(cap.memoryMB) + "}";
  }

  Capacity capacityFromJSON(const rj::Value &spec)
  {
    Capacity cap{.cores = 0, .memoryMB = 0};

    if (!spec.IsObject()) {
      throw std::runtime_error("Capacity is not an object");
    }

    if (spec.HasMember("cores")) {
      if (!spec["cores"].IsNumber()) {
        throw std::runtime_error("cores member of Capacity is not an integer");
      }
      cap.cores = spec["cores"].GetInt64();
    }

    if (spec.HasMember("memoryMB")) {
      if (!spec["memoryMB"].IsNumber()) {
        throw std::runtime_error(
            "memoryMB member of Capacity is not an integer");
      }
      cap.memoryMB = spec["memoryMB"].GetInt64();
    }

    return cap;
  }

  Capacity capacityFromTask(const Task &task)
  {
    Capacity cap{.cores = 0, .memoryMB = 0};

    cap.cores    = std::stoll(std::get<std::string>(task.job.at("cores")));
    cap.memoryMB = std::stoll(std::get<std::string>(task.job.at("memoryMB")));

    return cap;
  }

  void validateTaskParameters(const daggy::ConfigValues &job)
  {
    forking_executor::validateTaskParameters(job);

    const std::array<std::string, 2> fields{"cores", "memoryMB"};

    for (const auto &field : fields) {
      if (job.count(field) == 0)
        throw std::runtime_error("Missing required job parameter " + field);

      const auto &val = job.at(field);

      if (!std::holds_alternative<std::string>(val))
        throw std::runtime_error(field + " in capacity is not a string");

      try {
        std::stoll(std::get<std::string>(val));
      }
      catch (std::exception &e) {
        throw std::runtime_error(field + " in capacity is not an integer");
      }
    }
  }
}  // namespace daggy::executors::task::daggy_runner

DaggyRunnerTaskExecutor::DaggyRunnerTaskExecutor()
  : running_(true)
  , promptTask_(false)
  , monitorWorker_(&DaggyRunnerTaskExecutor::monitor, this)
{
}

DaggyRunnerTaskExecutor::~DaggyRunnerTaskExecutor()
{
  running_ = false;
  monitorWorker_.join();
}

std::string DaggyRunnerTaskExecutor::description() const
{
  std::stringstream ss;
  ss << "DaggyRunnerTaskExecutor running with " << runners_.size()
     << " runners: [";
  bool first = true;
  for (const auto &[runner, _] : runners_) {
    if (first) {
      first = false;
    }
    else {
      ss << ", ";
    }
    ss << runner;
  }
  ss << "]";
  return ss.str();
}

// Validates the job to ensure that all required values are set and are of
// the right type,
bool DaggyRunnerTaskExecutor::validateTaskParameters(const ConfigValues &job)
{
  daggy_runner::validateTaskParameters(job);

  return true;
}

std::vector<ConfigValues> DaggyRunnerTaskExecutor::expandTaskParameters(
    const ConfigValues &job, const ConfigValues &expansionValues)
{
  std::vector<ConfigValues> newValues;

  auto command =
      (job.count("command") == 0 ? Command{}
                                 : std::get<Command>(job.at("command")));

  auto environment = (job.count("environment") == 0
                          ? Command{}
                          : std::get<Command>(job.at("environment")));

  Command both(command);
  std::copy(environment.begin(), environment.end(), std::back_inserter(both));

  for (const auto &parts : interpolateValues(both, expansionValues)) {
    ConfigValues newCommand{job};
    newCommand["command"] =
        Command(parts.begin(), parts.begin() + command.size());
    newCommand["environment"] =
        Command(parts.begin() + command.size(), parts.end());
    newValues.emplace_back(newCommand);
  }

  return newValues;
}

// Runs the task
TaskFuture DaggyRunnerTaskExecutor::execute(DAGRunID runID,
                                            const std::string &taskName,
                                            const Task &task)
{
  auto taskUsed = capacityFromTask(task);

  std::string exe_runner;
  Capacity *exe_capacity;

  // Block until a host is found
  std::unique_lock<std::mutex> lock(runnersGuard_);
  // Wait for a host to be available
  runnersCV_.wait(lock, [&] {
    for (auto &[runner, capacity] : runners_) {
      if (capacity.cores >= taskUsed.cores and
          capacity.memoryMB >= taskUsed.memoryMB) {
        exe_runner   = runner;
        exe_capacity = &capacity;
        return true;
      }
    }
    return false;
  });
  exe_capacity->cores -= taskUsed.cores;
  exe_capacity->memoryMB -= taskUsed.memoryMB;

  std::stringstream ss;
  ss << exe_runner << "/v1/task/" << runID << "/" << taskName;
  auto url = ss.str();

  const auto response = HTTP_REQUEST(url, taskToJSON(task), "POST");

  RunningTask rt{.fut       = std::make_shared<Future<AttemptRecord>>(),
                 .runID     = runID,
                 .taskName  = taskName,
                 .resources = taskUsed};

  auto fut = rt.fut;
  {
    std::lock_guard<std::mutex> lock(rtGuard_);
    runningTasks_.emplace(std::make_pair(runID, taskName), std::move(rt));
  }
  return fut;
}

bool DaggyRunnerTaskExecutor::stop(DAGRunID runID, const std::string &taskName)
{
  return true;
}

daggy_runner::Capacity DaggyRunnerTaskExecutor::getRunnerCapacity(
    const std::string &runnerURL)
{
  // Try and get the capacity
  const auto &[code, doc] = JSON_HTTP_REQUEST(runnerURL + "/v1/capacity");
  if (code != HTTPCode::Ok) {
    return Capacity{};
  }

  return capacityFromJSON(doc["total"]);
}

void DaggyRunnerTaskExecutor::addRunner(const std::string &url)
{
  std::lock_guard<std::mutex> lock(runnersGuard_);
  runners_.emplace(url, getRunnerCapacity(url));
}

void DaggyRunnerTaskExecutor::monitor()
{
  std::unordered_map<std::string, Capacity> runners;

  while (running_) {
    std::this_thread::sleep_for(std::chrono::milliseconds(250));
    std::unordered_map<std::pair<DAGRunID, std::string>,
                       std::optional<AttemptRecord>>
        resolvedJobs;

    std::unordered_map<std::pair<DAGRunID, std::string>, Capacity>
        taskResources;

    // Cache what's running now
    {
      std::lock_guard<std::mutex> lock(rtGuard_);
      for (const auto &[tid, info] : runningTasks_) {
        taskResources.emplace(tid, info.resources);
      }
    }

    {
      std::lock_guard<std::mutex> lock(runnersGuard_);
      for (auto &[runnerURL, caps] : runners_) {
        rj::Document doc;
        try {
          auto [code, json] = JSON_HTTP_REQUEST(runnerURL + "/v1/poll");
          if (code != HTTPCode::Ok) {
            std::cout << "Unable to poll: " << code << ": " << dumpJSON(json)
                      << std::endl;
            continue;
          }

          doc.Swap(json);
        }
        catch (std::exception &e) {
          std::cout << "Unable to poll: " << e.what() << std::endl;
          continue;
        }

        if (!doc.IsArray()) {
          std::cout << "Got nonsense from poll: " << dumpJSON(doc) << std::endl;
          continue;
        }

        const auto tasks = doc.GetArray();
        for (size_t idx = 0; idx < tasks.Size(); ++idx) {
          const auto &task = tasks[idx];
          auto tid         = std::make_pair(task["runID"].GetInt64(),
                                            task["taskName"].GetString());
          auto it          = taskResources.find(tid);
          if (it != taskResources.end()) {
            caps.cores += it->second.cores;
            caps.memoryMB += it->second.memoryMB;
          }

          auto attempt = attemptRecordFromJSON(task["attempt"]);
          resolvedJobs.emplace(tid, attemptRecordFromJSON(task["attempt"]));
          promptTask_ = true;
          runnersCV_.notify_one();
        }
      }
    }

    std::vector<std::pair<DAGRunID, std::string>> completedTasks;
    {
      std::lock_guard<std::mutex> lock(rtGuard_);
      for (auto &[taskID, task] : runningTasks_) {
        auto it = resolvedJobs.find(taskID);
        if (it == resolvedJobs.end())
          continue;
        if (it->second.has_value()) {
          // Task has completed
          task.fut->set(std::move(it->second.value()));
          completedTasks.emplace_back(taskID);
        }
      }
      for (const auto &tid : completedTasks) {
        runningTasks_.extract(tid);
      }
    }
  }
}