// SPDX-License-Identifier: MIT
// SPDX-FileCopyrightText: 2026 Martino Ferrari

#include "source/flatudp/flatudp_source.hpp"
#include "source/registry.hpp"

#include <adwaita.h>

#include <algorithm>
#include <cctype>
#include <cstdint>
#include <cstdio>
#include <functional>
#include <memory>
#include <string>
#include <vector>

namespace udpscope {
namespace {

using namespace flatudp;
using ChangeCb = std::shared_ptr<std::function<void()>>;

std::string num(double v) {
  char b[48];
  std::snprintf(b, sizeof b, "%.10g", v);
  return b;
}

std::string trim(const std::string& s) {
  std::size_t a = 0, b = s.size();
  while (a < b && std::isspace(static_cast<unsigned char>(s[a]))) ++a;
  while (b > a && std::isspace(static_cast<unsigned char>(s[b - 1]))) --b;
  return s.substr(a, b - a);
}

GtkWidget* entry_row(const char* title) {
  GtkWidget* r = adw_entry_row_new();
  adw_preferences_row_set_title(ADW_PREFERENCES_ROW(r), title);
  adw_preferences_row_set_use_underline(ADW_PREFERENCES_ROW(r), TRUE);
  return r;
}

GtkWidget* spin_row(const char* title, double lo, double hi, double step, double def, int digits) {
  GtkWidget* r = GTK_WIDGET(adw_spin_row_new_with_range(lo, hi, step));
  adw_preferences_row_set_title(ADW_PREFERENCES_ROW(r), title);
  adw_preferences_row_set_use_underline(ADW_PREFERENCES_ROW(r), TRUE);
  adw_spin_row_set_digits(ADW_SPIN_ROW(r), static_cast<guint>(digits));
  adw_spin_row_set_value(ADW_SPIN_ROW(r), def);
  return r;
}

GtkWidget* combo_row(const char* title, const char* const* items) {
  GtkWidget* r = adw_combo_row_new();
  adw_preferences_row_set_title(ADW_PREFERENCES_ROW(r), title);
  adw_preferences_row_set_use_underline(ADW_PREFERENCES_ROW(r), TRUE);
  adw_combo_row_set_model(ADW_COMBO_ROW(r), G_LIST_MODEL(gtk_string_list_new(items)));
  return r;
}

GtkWidget* expander(const char* title, std::initializer_list<GtkWidget*> rows) {
  GtkWidget* e = adw_expander_row_new();
  adw_preferences_row_set_title(ADW_PREFERENCES_ROW(e), title);
  for (GtkWidget* r : rows) adw_expander_row_add_row(ADW_EXPANDER_ROW(e), r);
  return e;
}

std::string text_of(GtkWidget* w) { return gtk_editable_get_text(GTK_EDITABLE(w)); }
double value_of(GtkWidget* w) { return adw_spin_row_get_value(ADW_SPIN_ROW(w)); }
guint sel_of(GtkWidget* w) { return adw_combo_row_get_selected(ADW_COMBO_ROW(w)); }

void mark(GtkWidget* w, bool bad) {
  if (bad) {
    gtk_widget_add_css_class(w, "error");
  } else {
    gtk_widget_remove_css_class(w, "error");
  }
}

/// One signal's editing widgets; `row` is the `AdwEntryRow` that holds the others. `vec` ("Vector as":
/// Channels or Waveform) is shown only while `count` is above 1.
struct SigRow {
  GtkWidget *row, *type, *count, *vec;
};

/// The form's widgets, shared by every signal closure and every `ConfigForm` closure. The raw
/// widget pointers are valid while the chooser keeps the rows.
struct Form : std::enable_shared_from_this<Form> {
  GtkWidget *port, *bind, *multicast, *iface, *rate, *endian, *group;
  std::vector<SigRow> sigs;
  ChangeCb changed = std::make_shared<std::function<void()>>();
  bool updating = false;
  bool alive = true;  ///< cleared when the chooser destroys the rows; handlers then touch nothing

  std::vector<Row> rows_now() const {
    std::vector<Row> rows;
    for (const SigRow& s : sigs) {
      Row r;
      r.name = trim(text_of(s.row));
      r.type = static_cast<Type>(std::min<guint>(gtk_drop_down_get_selected(GTK_DROP_DOWN(s.type)), 9));
      r.count = static_cast<std::uint32_t>(gtk_spin_button_get_value_as_int(GTK_SPIN_BUTTON(s.count)));
      r.wave = r.count > 1 && gtk_drop_down_get_selected(GTK_DROP_DOWN(s.vec)) == 1;
      rows.push_back(r);
    }
    return rows;
  }

  /// The first `S<n>` that no row uses.
  std::string next_name() const {
    const std::vector<Row> rows = rows_now();
    for (int n = 1;; ++n) {
      const std::string name = "S" + std::to_string(n);
      bool used = false;
      for (const Row& r : rows) used = used || r.name == name;
      if (!used) return name;
    }
  }

  /// Bad addresses are marked with the `error` style; the group's subtitle carries the signal list's
  /// own state, the first rule it breaks or the size it implies.
  void refresh() {
    mark(bind, !text_of(bind).empty() && !valid_ipv4(text_of(bind)));
    mark(multicast, !text_of(multicast).empty() && !valid_multicast(text_of(multicast)));
    mark(iface, !text_of(iface).empty() && !valid_ipv4(text_of(iface)));
    // "Vector as" belongs to a vector row only; a row back at one element returns to Channels.
    for (const SigRow& s : sigs) {
      const bool vec = gtk_spin_button_get_value_as_int(GTK_SPIN_BUTTON(s.count)) > 1;
      gtk_widget_set_visible(s.vec, vec);
      if (!vec && gtk_drop_down_get_selected(GTK_DROP_DOWN(s.vec)) != 0)
        gtk_drop_down_set_selected(GTK_DROP_DOWN(s.vec), 0);
    }
    const std::vector<Row> rows = rows_now();
    const std::string p = flatudp::problem(rows);
    std::string sub = p;
    if (p.empty()) {
      sub = std::to_string(channel_count(rows)) + (channel_count(rows) == 1 ? " channel, " : " channels, ") +
            std::to_string(datagram_size(rows)) + " bytes per datagram";
    }
    adw_expander_row_set_subtitle(ADW_EXPANDER_ROW(group), sub.c_str());
  }

  void fire() {
    if (!updating && changed && *changed) (*changed)();
  }

  SourceConfig read() const {
    SourceConfig c;
    c.set("port", num(value_of(port)));
    if (!text_of(bind).empty()) c.set("bind", text_of(bind));
    if (!text_of(multicast).empty()) c.set("multicast", text_of(multicast));
    if (!text_of(iface).empty()) c.set("iface", text_of(iface));
    c.set("rate", num(value_of(rate)));
    c.set("endian", sel_of(endian) == 1 ? "big" : "little");
    c.set("signals", format(rows_now()));
    return c;
  }

  void add_row(const Row& r);
  void remove_row(GtkWidget* row);

  void write(const SourceConfig& cfg) {
    const FlatUdpSettings s = FlatUdpSettings::from(cfg);
    updating = true;
    adw_spin_row_set_value(ADW_SPIN_ROW(port), s.port);
    gtk_editable_set_text(GTK_EDITABLE(bind), s.bind.c_str());
    gtk_editable_set_text(GTK_EDITABLE(multicast), s.multicast.c_str());
    gtk_editable_set_text(GTK_EDITABLE(iface), s.iface.c_str());
    if (s.rate > 0.0) adw_spin_row_set_value(ADW_SPIN_ROW(rate), s.rate);
    adw_combo_row_set_selected(ADW_COMBO_ROW(endian), s.big_endian ? 1 : 0);
    while (!sigs.empty()) {
      GtkWidget* row = sigs.back().row;
      sigs.pop_back();
      adw_expander_row_remove(ADW_EXPANDER_ROW(group), row);
    }
    for (const Row& r : s.rows) add_row(r);
    updating = false;
    refresh();
  }

  bool valid() const { return FlatUdpSettings::from(read()).problem().empty(); }
};

using FormPtr = std::shared_ptr<Form>;

/// A remove button's context: which form, which row.
struct RowCtx {
  FormPtr form;
  GtkWidget* row;
};

void on_notify(GObject*, GParamSpec*, gpointer user) {
  Form& f = **static_cast<FormPtr*>(user);
  if (!f.alive) return;
  f.refresh();
  f.fire();
}

void on_edited(GtkEditable*, gpointer user) {
  Form& f = **static_cast<FormPtr*>(user);
  if (!f.alive) return;
  f.refresh();
  f.fire();
}

void on_spin(GtkSpinButton*, gpointer user) {
  Form& f = **static_cast<FormPtr*>(user);
  if (!f.alive) return;
  f.refresh();
  f.fire();
}

void on_add(GtkButton*, gpointer user) {
  FormPtr f = *static_cast<FormPtr*>(user);
  if (!f->alive) return;
  f->add_row(Row{f->next_name(), Type::F32, 1});
  adw_expander_row_set_expanded(ADW_EXPANDER_ROW(f->group), TRUE);
  f->refresh();
  f->fire();
}

void on_remove(GtkButton*, gpointer user) {
  // Copy first: removing the row finalizes this button, and with it this context.
  RowCtx* c = static_cast<RowCtx*>(user);
  FormPtr f = c->form;
  GtkWidget* row = c->row;
  if (!f->alive) return;
  f->remove_row(row);
}

void free_form(gpointer d, GClosure*) { delete static_cast<FormPtr*>(d); }
void free_ctx(gpointer d, GClosure*) { delete static_cast<RowCtx*>(d); }

/// "destroy" on a row group: the siblings the handlers reach by raw pointer may already be gone.
void on_form_destroy(GtkWidget*, gpointer user) { (**static_cast<FormPtr*>(user)).alive = false; }

void hook_destroy(GtkWidget* w, const FormPtr& f) {
  g_signal_connect_data(w, "destroy", G_CALLBACK(on_form_destroy), new FormPtr(f), free_form,
                        static_cast<GConnectFlags>(0));
}

void hook_notify(GtkWidget* w, const char* signal, const FormPtr& f) {
  g_signal_connect_data(w, signal, G_CALLBACK(on_notify), new FormPtr(f), free_form,
                        static_cast<GConnectFlags>(0));
}

void hook_entry(GtkWidget* w, const FormPtr& f) {
  g_signal_connect_data(w, "changed", G_CALLBACK(on_edited), new FormPtr(f), free_form,
                        static_cast<GConnectFlags>(0));
}

void Form::add_row(const Row& r) {
  FormPtr self = shared_from_this();
  GtkWidget* row = adw_entry_row_new();
  adw_preferences_row_set_title(ADW_PREFERENCES_ROW(row), "Name");
  gtk_editable_set_text(GTK_EDITABLE(row), r.name.c_str());

  const char* names[11];
  for (std::size_t i = 0; i < 10; ++i) names[i] = type_name(static_cast<Type>(i));
  names[10] = nullptr;
  GtkWidget* type = gtk_drop_down_new_from_strings(names);
  gtk_drop_down_set_selected(GTK_DROP_DOWN(type), static_cast<guint>(r.type));
  gtk_widget_set_valign(type, GTK_ALIGN_CENTER);
  gtk_widget_set_name(type, "flatudp-type");

  // The spin clamps to 1..4096, so a hand-edited session with a count outside it is repaired here.
  GtkWidget* count = gtk_spin_button_new_with_range(1, kMaxCount, 1);
  gtk_spin_button_set_value(GTK_SPIN_BUTTON(count), r.count);
  gtk_widget_set_valign(count, GTK_ALIGN_CENTER);
  gtk_widget_set_tooltip_text(count, "Elements: 1 is a scalar signal, more make a vector signal");
  gtk_widget_set_name(count, "flatudp-count");

  static const char* const kVec[] = {"Channels", "Waveform", nullptr};
  GtkWidget* vec = gtk_drop_down_new_from_strings(kVec);
  gtk_drop_down_set_selected(GTK_DROP_DOWN(vec), r.wave && r.count > 1 ? 1 : 0);
  gtk_widget_set_valign(vec, GTK_ALIGN_CENTER);
  gtk_widget_set_visible(vec, r.count > 1);
  gtk_widget_set_tooltip_text(vec,
                              "Vector as: Channels makes one channel per element, one sample per cycle; "
                              "Waveform makes one channel of all the elements per cycle");
  gtk_widget_set_name(vec, "flatudp-vector");

  GtkWidget* rm = gtk_button_new_with_label("Remove");
  gtk_widget_set_valign(rm, GTK_ALIGN_CENTER);
  gtk_widget_set_name(rm, "flatudp-remove");

  adw_entry_row_add_suffix(ADW_ENTRY_ROW(row), type);
  adw_entry_row_add_suffix(ADW_ENTRY_ROW(row), count);
  adw_entry_row_add_suffix(ADW_ENTRY_ROW(row), vec);
  adw_entry_row_add_suffix(ADW_ENTRY_ROW(row), rm);

  hook_entry(row, self);
  hook_notify(type, "notify::selected", self);
  hook_notify(vec, "notify::selected", self);
  g_signal_connect_data(count, "value-changed", G_CALLBACK(on_spin), new FormPtr(self), free_form,
                        static_cast<GConnectFlags>(0));
  g_signal_connect_data(rm, "clicked", G_CALLBACK(on_remove), new RowCtx{self, row}, free_ctx,
                        static_cast<GConnectFlags>(0));

  adw_expander_row_add_row(ADW_EXPANDER_ROW(group), row);
  sigs.push_back(SigRow{row, type, count, vec});
}

void Form::remove_row(GtkWidget* row) {
  for (auto it = sigs.begin(); it != sigs.end(); ++it) {
    if (it->row == row) {
      sigs.erase(it);
      adw_expander_row_remove(ADW_EXPANDER_ROW(group), row);
      break;
    }
  }
  refresh();
  fire();
}

class FlatUdpKind final : public SourceKind {
 public:
  std::string id() const override { return "flatudp"; }
  std::string display_name() const override { return "Flat UDP (MARTe2 UDPSender)"; }
  bool has_datagrams() const override { return true; }

  std::string identity(const SourceConfig& cfg) const override {
    return FlatUdpSettings::from(cfg).identity();
  }

  std::unique_ptr<DataSource> make(const SourceConfig& cfg) const override {
    return std::make_unique<FlatUdpSource>(cfg);
  }

  ConfigForm make_config_form() const override {
    auto f = std::make_shared<Form>();
    static const char* const kEndian[] = {"Little endian", "Big endian", nullptr};

    f->port = spin_row("_Port", 1, 65535, 1, kDefaultPort, 0);
    f->bind = entry_row("_Bind address");
    f->multicast = entry_row("_Multicast group");
    f->iface = entry_row("Multicast _interface");
    f->rate = spin_row("Cycle _rate (Hz)", 0.001, 1000000, 1, 1000, 3);
    f->endian = combo_row("_Byte order", kEndian);

    GtkWidget* net = expander("Network", {f->port, f->bind, f->multicast, f->iface});
    GtkWidget* timing = expander("Timing and format", {f->rate, f->endian});
    f->group = adw_expander_row_new();
    adw_preferences_row_set_title(ADW_PREFERENCES_ROW(f->group), "Signals");
    adw_expander_row_set_expanded(ADW_EXPANDER_ROW(net), TRUE);
    adw_expander_row_set_expanded(ADW_EXPANDER_ROW(f->group), TRUE);

    GtkWidget* add = gtk_button_new_with_label("Add signal");
    gtk_widget_set_valign(add, GTK_ALIGN_CENTER);
    gtk_widget_set_name(add, "flatudp-add");
    adw_expander_row_add_suffix(ADW_EXPANDER_ROW(f->group), add);
    g_signal_connect_data(add, "clicked", G_CALLBACK(on_add), new FormPtr(f), free_form,
                          static_cast<GConnectFlags>(0));

    for (GtkWidget* w : {net, timing, f->group}) hook_destroy(w, f);
    for (GtkWidget* w : {f->bind, f->multicast, f->iface}) hook_entry(w, f);
    for (GtkWidget* w : {f->port, f->rate}) hook_notify(w, "notify::value", f);
    hook_notify(f->endian, "notify::selected", f);
    f->refresh();

    ConfigForm out;
    out.rows = {net, timing, f->group};
    out.description =
        "The signal list must match the sender's exactly, in order: the datagrams carry no "
        "description, and a datagram of any other size is dropped. A vector signal is either "
        "one channel per element or, as a waveform, one channel of all its elements";
    out.focus = f->rate;
    out.write = [f](const SourceConfig& c) { f->write(c); };
    out.read = [f]() { return f->read(); };
    out.valid = [f]() { return f->valid(); };
    ChangeCb cb = f->changed;
    out.on_change = [cb](std::function<void()> fn) { *cb = std::move(fn); };
    return out;
  }
};

}  // namespace

std::unique_ptr<SourceKind> make_flatudp_kind() { return std::make_unique<FlatUdpKind>(); }

}  // namespace udpscope