/* Node-type for signal generation.
 *
 * Author: Steffen Vogel <post@steffenvogel.de>
 * SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University
 * SPDX-License-Identifier: Apache-2.0
 */

#include <cmath>
#include <cstring>
#include <list>

#include <villas/exceptions.hpp>
#include <villas/node_compat.hpp>
#include <villas/nodes/signal.hpp>
#include <villas/utils.hpp>

using namespace villas;
using namespace villas::node;
using namespace villas::utils;

SignalNodeSignal::SignalNodeSignal(json_t *json)
    : type(Type::MIXED), frequency(1.0), amplitude(1.0), stddev(0.2),
      offset(0.0), pulse_width(1.0), pulse_low(0.0), pulse_high(1.0),
      phase(0.0) {
  parse(json);

  last = offset;
}

enum SignalNodeSignal::Type
SignalNodeSignal::lookupType(const std::string &type) {
  if (type == "random")
    return Type::RANDOM;
  else if (type == "sine")
    return Type::SINE;
  else if (type == "square")
    return Type::SQUARE;
  else if (type == "triangle")
    return Type::TRIANGLE;
  else if (type == "ramp")
    return Type::RAMP;
  else if (type == "counter")
    return Type::COUNTER;
  else if (type == "constant")
    return Type::CONSTANT;
  else if (type == "mixed")
    return Type::MIXED;
  else if (type == "pulse")
    return Type::PULSE;

  throw std::invalid_argument("Invalid signal type");
}

std::string SignalNodeSignal::typeToString(enum Type type) {
  switch (type) {
  case Type::CONSTANT:
    return "constant";

  case Type::SINE:
    return "sine";

  case Type::TRIANGLE:
    return "triangle";

  case Type::SQUARE:
    return "square";

  case Type::RAMP:
    return "ramp";

  case Type::COUNTER:
    return "counter";

  case Type::RANDOM:
    return "random";

  case Type::MIXED:
    return "mixed";

  case Type::PULSE:
    return "pulse";

  default:
    return nullptr;
  }
}

void SignalNodeSignal::start() { last = offset; }

void SignalNodeSignal::read(unsigned c, double t, double r, SignalData *d) {
  switch (type) {
  case Type::CONSTANT:
    d->f = offset + amplitude;
    break;

  case Type::SINE:
    d->f = offset + amplitude * sin(t * frequency * 2 * M_PI + phase);
    break;

  case Type::TRIANGLE:
    d->f =
        offset +
        amplitude *
            (fabs(fmod(t * frequency + (phase / (2 * M_PI)), 1) - .5) - 0.25) *
            4;
    break;

  case Type::SQUARE:
    d->f = offset +
           amplitude *
               ((fmod(t * frequency + (phase / (2 * M_PI)), 1) < .5) ? -1 : 1);
    break;

  case Type::RAMP:
    d->f = offset + amplitude * fmod(t, frequency);
    break;

  case Type::COUNTER:
    d->f = offset + amplitude * c;
    break;

  case Type::RANDOM:
    last += boxMuller(0, stddev);
    d->f = last;
    break;

  case Type::MIXED:
    break;

  case Type::PULSE:
    d->f =
        abs(fmod(t * frequency + (phase / (2 * M_PI)), 1)) <= (pulse_width / r)
            ? pulse_high
            : pulse_low;
    d->f += offset;
    break;
  }
}

int SignalNodeSignal::parse(json_t *json) {
  int ret;
  const char *type_str;

  json_error_t err;

  ret = json_unpack_ex(
      json, &err, 0,
      "{ s: s, s?: F, s?: F, s?: F, s?: F, s?: F, s?: F, s?: F, s?: F }",
      "signal", &type_str, "frequency", &frequency, "amplitude", &amplitude,
      "stddev", &stddev, "offset", &offset, "pulse_width", &pulse_width,
      "pulse_low", &pulse_low, "pulse_high", &pulse_high, "phase", &phase);
  if (ret)
    throw ConfigError(json, err, "node-config-node-signal");

  try {
    type = lookupType(type_str);
  } catch (std::invalid_argument &e) {
    throw ConfigError(json, "node-config-node-signal-type",
                      "Unknown signal type: {}", type_str);
  }

  return 0;
}

Signal::Ptr SignalNodeSignal::toSignal(Signal::Ptr tpl) const {
  auto isDefaultName = tpl->name.rfind("signal", 0) == 0;

  auto name = isDefaultName ? typeToString(type) : tpl->name;
  auto unit = tpl->unit;

  auto sig = std::make_shared<Signal>(name, unit, SignalType::FLOAT);

  sig->init.f = offset;

  return sig;
}

SignalNode::SignalNode(const uuid_t &id, const std::string &name)
    : Node(id, name), task(CLOCK_MONOTONIC), rt(1), rate(10),
      monitor_missed(true), limit(-1), missed_steps(0) {}

int SignalNode::prepare() {
  assert(state == State::CHECKED);

  for (unsigned i = 0; i < signals.size(); i++) {
    auto &sig = (*in.signals)[i];
    auto &ssig = signals[i];

    sig = ssig.toSignal(sig);
  }

  if (logger->level() <= spdlog::level::debug)
    in.signals->dump(logger);

  return Node::prepare();
}

int SignalNode::parse(json_t *json) {
  int r = -1, m = -1, ret = Node::parse(json);
  if (ret)
    return ret;

  json_error_t err;

  size_t i;
  json_t *json_signals, *json_signal;

  ret = json_unpack_ex(json, &err, 0,
                       "{ s?: b, s?: i, s?: F, s?: b, s: { s: o } }",
                       "realtime", &r, "limit", &limit, "rate", &rate,
                       "monitor_missed", &m, "in", "signals", &json_signals);
  if (ret)
    throw ConfigError(json, err, "node-config-node-signal");

  if (r >= 0)
    rt = r != 0;

  if (m >= 0)
    monitor_missed = m != 0;

  signals.clear();
  unsigned j = 0;
  json_array_foreach(json_signals, i, json_signal) {
    auto sig = SignalNodeSignal(json_signal);

    if (sig.type == SignalNodeSignal::Type::MIXED)
      sig.type =
          (SignalNodeSignal::Type)(j++ % (int)SignalNodeSignal::Type::MIXED);

    signals.push_back(sig);
  }

  state = State::PARSED;

  return 0;
}

int SignalNode::start() {
  assert(state == State::PREPARED || state == State::PAUSED);

  missed_steps = 0;
  started = time_now();

  for (auto sig : signals)
    sig.start();

  // Setup task
  if (rt)
    task.setRate(rate);

  int ret = Node::start();
  if (!ret)
    state = State::STARTED;

  return ret;
}

int SignalNode::stop() {
  assert(state == State::STARTED || state == State::PAUSED ||
         state == State::STOPPING);

  int ret = Node::stop();
  if (ret)
    return ret;

  if (rt)
    task.stop();

  if (missed_steps > 0 && monitor_missed)
    logger->warn("Missed a total of {} steps.", missed_steps);

  state = State::STOPPED;

  return 0;
}

int SignalNode::_read(struct Sample *smps[], unsigned cnt) {
  struct Sample *t = smps[0];

  struct timespec ts;
  uint64_t steps, counter = sequence - sequence_init;

  assert(cnt == 1);

  if (rt)
    ts = time_now();
  else {
    struct timespec offset = time_from_double(counter * 1.0 / rate);
    ts = time_add(&started, &offset);
  }

  double running = time_delta(&started, &ts);

  t->flags = (int)SampleFlags::HAS_TS_ORIGIN | (int)SampleFlags::HAS_DATA |
             (int)SampleFlags::HAS_SEQUENCE;
  t->ts.origin = ts;
  t->sequence = sequence;
  t->length = MIN(signals.size(), t->capacity);
  t->signals = in.signals;

  for (unsigned i = 0; i < t->length; i++) {
    auto &sig = signals[i];

    sig.read(counter, running, rate, &t->data[i]);
  }

  if (limit > 0 && counter >= (unsigned)limit) {
    logger->info("Reached limit.");

    setState(State::STOPPING);
    return -1;
  }

  // Throttle output if desired
  if (rt) {
    // Block until 1/p->rate seconds elapsed
    steps = task.wait();
    if (steps > 1 && monitor_missed) {
      logger->debug("Missed steps: {}", steps - 1);
      missed_steps += steps - 1;
    }
  } else
    steps = 1;

  sequence += steps;

  return 1;
}

const std::string &SignalNode::getDetails() {
  if (details.empty()) {
    details = fmt::format("rt={}, rate={}", rt ? "yes" : "no", rate);

    if (limit > 0)
      details += fmt::format(", limit={}", limit);
  }

  return details;
}

std::vector<int> SignalNode::getPollFDs() {
  if (rt)
    return {task.getFD()};

  return {};
}

// Register node
static char n[] = "signal.v2";
static char d[] = "Signal generator";
static NodePlugin<SignalNode, n, d,
                  (int)NodeFactory::Flags::SUPPORTS_READ |
                      (int)NodeFactory::Flags::SUPPORTS_POLL>
    p;
