/* Sending statistics to another node.
 *
 * 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 <cstring>

#include <villas/exceptions.hpp>
#include <villas/hook.hpp>
#include <villas/node_compat.hpp>
#include <villas/nodes/stats.hpp>
#include <villas/sample.hpp>
#include <villas/stats.hpp>
#include <villas/super_node.hpp>
#include <villas/utils.hpp>

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

static NodeList nodes; // The global list of nodes

int villas::node::stats_node_signal_destroy(struct stats_node_signal *s) {
  free(s->node_str);

  return 0;
}

int villas::node::stats_node_signal_parse(struct stats_node_signal *s,
                                          json_t *json) {
  json_error_t err;

  int ret;
  const char *stats;
  char *metric, *type, *node, *cpy, *lasts;

  ret = json_unpack_ex(json, &err, 0, "{ s: s }", "stats", &stats);
  if (ret)
    throw ConfigError(json, err, "node-config-node-stats");

  cpy = strdup(stats);

  node = strtok_r(cpy, ".", &lasts);
  if (!node)
    goto invalid_format;

  metric = strtok_r(nullptr, ".", &lasts);
  if (!metric)
    goto invalid_format;

  type = strtok_r(nullptr, ".", &lasts);
  if (!type)
    goto invalid_format;

  s->metric = Stats::lookupMetric(metric);
  s->type = Stats::lookupType(type);

  s->node_str = strdup(node);

  free(cpy);
  return 0;

invalid_format:
  free(cpy);
  return -1;
}

int villas::node::stats_node_type_start(villas::node::SuperNode *sn) {
  if (sn == nullptr)
    throw RuntimeError("Stats node-type requires super-node");

  nodes = sn->getNodes();

  return 0;
}

int villas::node::stats_node_prepare(NodeCompat *n) {
  auto *s = n->getData<struct stats_node>();

  assert(n->getInputSignals(false)->size() == 0);

  // Generate signal list
  for (size_t i = 0; i < list_length(&s->signals); i++) {
    struct stats_node_signal *stats_sig =
        (struct stats_node_signal *)list_at(&s->signals, i);

    const char *metric = Stats::metrics[stats_sig->metric].name;
    const char *type = Stats::types[stats_sig->type].name;

    auto name = fmt::format("{}.{}.{}", stats_sig->node_str, metric, type);

    auto sig = std::make_shared<Signal>(
        name.c_str(), Stats::metrics[stats_sig->metric].unit,
        Stats::types[stats_sig->type].signal_type);

    n->in.signals->push_back(sig);
  }

  return 0;
}

int villas::node::stats_node_start(NodeCompat *n) {
  auto *s = n->getData<struct stats_node>();

  s->task.setRate(s->rate);

  for (size_t i = 0; i < list_length(&s->signals); i++) {
    struct stats_node_signal *stats_sig =
        (struct stats_node_signal *)list_at(&s->signals, i);

    stats_sig->node = nodes.lookup(stats_sig->node_str);
    if (!stats_sig->node)
      throw ConfigError(n->getConfig(), "node-config-node-stats-node",
                        "Invalid reference node {}", stats_sig->node_str);
  }

  return 0;
}

int villas::node::stats_node_stop(NodeCompat *n) {
  auto *s = n->getData<struct stats_node>();

  s->task.stop();

  return 0;
}

char *villas::node::stats_node_print(NodeCompat *n) {
  auto *s = n->getData<struct stats_node>();

  return strf("rate=%f", s->rate);
}

int villas::node::stats_node_init(NodeCompat *n) {
  int ret;
  auto *s = n->getData<struct stats_node>();

  new (&s->task) Task(CLOCK_MONOTONIC);

  ret = list_init(&s->signals);
  if (ret)
    return ret;

  return 0;
}

int villas::node::stats_node_destroy(NodeCompat *n) {
  int ret;
  auto *s = n->getData<struct stats_node>();

  s->task.~Task();

  ret = list_destroy(&s->signals, (dtor_cb_t)stats_node_signal_destroy, true);
  if (ret)
    return ret;

  return 0;
}

int villas::node::stats_node_parse(NodeCompat *n, json_t *json) {
  auto *s = n->getData<struct stats_node>();

  int ret;
  size_t i;
  json_error_t err;
  json_t *json_signals, *json_signal;

  ret = json_unpack_ex(json, &err, 0, "{ s: F, s: { s: o } }", "rate", &s->rate,
                       "in", "signals", &json_signals);
  if (ret)
    throw ConfigError(json, err, "node-config-node-stats");

  if (s->rate <= 0)
    throw ConfigError(json, "node-config-node-stats-rate",
                      "Setting 'rate' must be positive");

  if (!json_is_array(json_signals))
    throw ConfigError(json, "node-config-node-stats-in-signals",
                      "Setting 'in.signals' must be an array");

  json_array_foreach(json_signals, i, json_signal) {
    auto *stats_sig = new struct stats_node_signal;
    if (!stats_sig)
      throw MemoryAllocationError();

    ret = stats_node_signal_parse(stats_sig, json_signal);
    if (ret)
      throw ConfigError(json_signal, "node-config-node-stats-signals",
                        "Failed to parse statistics signal definition");

    list_push(&s->signals, stats_sig);
  }

  return 0;
}

int villas::node::stats_node_read(NodeCompat *n, struct Sample *const smps[],
                                  unsigned cnt) {
  auto *s = n->getData<struct stats_node>();

  if (!cnt)
    return 0;

  s->task.wait();

  unsigned len = MIN(list_length(&s->signals), smps[0]->capacity);

  for (size_t i = 0; i < len; i++) {
    struct stats_node_signal *sig =
        (struct stats_node_signal *)list_at(&s->signals, i);

    auto st = sig->node->getStats();
    if (!st)
      return -1;

    smps[0]->data[i] = st->getValue(sig->metric, sig->type);
  }

  smps[0]->length = len;
  smps[0]->flags = (int)SampleFlags::HAS_DATA;
  smps[0]->signals = n->getInputSignals(false);

  return 1;
}

int villas::node::stats_node_poll_fds(NodeCompat *n, int fds[]) {
  auto *s = n->getData<struct stats_node>();

  fds[0] = s->task.getFD();

  return 0;
}

static NodeCompatType p;

__attribute__((constructor(110))) static void register_plugin() {
  p.name = "stats";
  p.description = "Send statistics to another node";
  p.vectorize = 1;
  p.flags = (int)NodeFactory::Flags::PROVIDES_SIGNALS;
  p.size = sizeof(struct stats_node);
  p.type.start = stats_node_type_start;
  p.parse = stats_node_parse;
  p.init = stats_node_init;
  p.destroy = stats_node_destroy;
  p.print = stats_node_print;
  p.prepare = stats_node_prepare;
  p.start = stats_node_start;
  p.stop = stats_node_stop;
  p.read = stats_node_read;
  p.poll_fds = stats_node_poll_fds;

  static NodeCompatFactory ncp(&p);
}