#include "source_base.h"
#include "config.h"
#include "git.h"
#include "info.h"
#include "terminal.h"
#include <fstream>

Source::BaseView::BaseView(const boost::filesystem::path &file_path, const Glib::RefPtr<Gsv::Language> &language) : Gsv::View(), file_path(file_path), language(language), status_diagnostics(0, 0, 0) {
  load(true);
  get_buffer()->place_cursor(get_buffer()->get_iter_at_offset(0));

  signal_focus_in_event().connect([this](GdkEventFocus *event) {
    if(this->last_write_time != static_cast<std::time_t>(-1))
      check_last_write_time();
    return false;
  });

  monitor_file();

  if(language) {
    get_source_buffer()->set_language(language);
    auto language_id = language->get_id();
    if(language_id == "chdr" || language_id == "cpphdr" || language_id == "c" ||
       language_id == "cpp" || language_id == "objc" || language_id == "java" ||
       language_id == "js" || language_id == "ts" || language_id == "proto" ||
       language_id == "c-sharp" || language_id == "html" || language_id == "cuda" ||
       language_id == "php" || language_id == "rust" || language_id == "swift" ||
       language_id == "go" || language_id == "scala" || language_id == "opencl" ||
       language_id == "json" || language_id == "css")
      is_bracket_language = true;
  }
}

Source::BaseView::~BaseView() {
  monitor_changed_connection.disconnect();
  delayed_monitor_changed_connection.disconnect();
}

bool Source::BaseView::load(bool not_undoable_action) {
  boost::system::error_code ec;
  last_write_time = boost::filesystem::last_write_time(file_path, ec);
  if(ec)
    last_write_time = static_cast<std::time_t>(-1);

  disable_spellcheck = true;
  if(not_undoable_action)
    get_source_buffer()->begin_not_undoable_action();

  class Guard {
  public:
    Source::BaseView *view;
    bool not_undoable_action;
    ~Guard() {
      if(not_undoable_action)
        view->get_source_buffer()->end_not_undoable_action();
      view->disable_spellcheck = false;
    }
  };
  Guard guard{this, not_undoable_action};

  if(language) {
    std::ifstream input(file_path.string(), std::ofstream::binary);
    if(input) {
      std::stringstream ss;
      ss << input.rdbuf();
      Glib::ustring ustr = ss.str();

      bool valid = true;
      Glib::ustring::iterator iter;
      while(!ustr.validate(iter)) {
        auto next_char_iter = iter;
        next_char_iter++;
        ustr.replace(iter, next_char_iter, "?");
        valid = false;
      }

      if(!valid)
        Terminal::get().print("Warning: " + file_path.string() + " is not a valid UTF-8 file. Saving might corrupt the file.\n");

      if(get_buffer()->size() == 0)
        get_buffer()->insert_at_cursor(ustr);
      else
        replace_text(ustr.raw());
    }
    else
      return false;
  }
  else {
    std::ifstream input(file_path.string(), std::ofstream::binary);
    if(input) {
      std::stringstream ss;
      ss << input.rdbuf();
      Glib::ustring ustr = ss.str();

      if(ustr.validate()) {
        if(get_buffer()->size() == 0)
          get_buffer()->insert_at_cursor(ustr);
        else
          replace_text(ustr.raw());
      }
      else {
        Terminal::get().print("Error: " + file_path.string() + " is not a valid UTF-8 file.\n", true);
        return false;
      }
    }
    else
      return false;
  }

  get_buffer()->set_modified(false);
  return true;
}

void Source::BaseView::replace_text(const std::string &new_text) {
  get_buffer()->begin_user_action();

  if(get_buffer()->size() == 0) {
    get_buffer()->insert_at_cursor(new_text);
    get_buffer()->end_user_action();
    return;
  }
  else if(new_text.empty()) {
    get_buffer()->set_text(new_text);
    get_buffer()->end_user_action();
    return;
  }

  auto iter = get_buffer()->get_insert()->get_iter();
  int cursor_line_nr = iter.get_line();
  int cursor_line_offset = iter.ends_line() ? std::numeric_limits<int>::max() : iter.get_line_offset();

  std::vector<std::pair<const char *, const char *>> new_lines;

  const char *line_start = new_text.c_str();
  for(const char &chr : new_text) {
    if(chr == '\n') {
      new_lines.emplace_back(line_start, &chr + 1);
      line_start = &chr + 1;
    }
  }
  if(new_text.empty() || new_text.back() != '\n')
    new_lines.emplace_back(line_start, &new_text[new_text.size()]);

  try {
    auto hunks = Git::Repository::Diff::get_hunks(get_buffer()->get_text().raw(), new_text);

    for(auto it = hunks.rbegin(); it != hunks.rend(); ++it) {
      bool place_cursor = false;
      Gtk::TextIter start;
      if(it->old_lines.second != 0) {
        start = get_buffer()->get_iter_at_line(it->old_lines.first - 1);
        auto end = get_buffer()->get_iter_at_line(it->old_lines.first - 1 + it->old_lines.second);

        if(cursor_line_nr >= start.get_line() && cursor_line_nr < end.get_line()) {
          if(it->new_lines.second != 0) {
            place_cursor = true;
            int line_diff = cursor_line_nr - start.get_line();
            cursor_line_nr += static_cast<int>(0.5 + (static_cast<float>(line_diff) / it->old_lines.second) * it->new_lines.second) - line_diff;
          }
        }

        get_buffer()->erase(start, end);
        start = get_buffer()->get_iter_at_line(it->old_lines.first - 1);
      }
      else
        start = get_buffer()->get_iter_at_line(it->old_lines.first);
      if(it->new_lines.second != 0) {
        get_buffer()->insert(start, new_lines[it->new_lines.first - 1].first, new_lines[it->new_lines.first - 1 + it->new_lines.second - 1].second);
        if(place_cursor)
          place_cursor_at_line_offset(cursor_line_nr, cursor_line_offset);
      }
    }
  }
  catch(...) {
    Terminal::get().print("Error: Could not replace text in buffer\n", true);
  }

  get_buffer()->end_user_action();
}

void Source::BaseView::rename(const boost::filesystem::path &path) {
  file_path = path;

  if(update_status_file_path)
    update_status_file_path(this);
  if(update_tab_label)
    update_tab_label(this);
}

void Source::BaseView::monitor_file() {
#ifdef __APPLE__ // TODO: Gio file monitor is bugged on MacOS
  class Recursive {
  public:
    static void f(BaseView *view, std::time_t last_write_time_) {
      view->delayed_monitor_changed_connection.disconnect();
      view->delayed_monitor_changed_connection = Glib::signal_timeout().connect([view, last_write_time_]() {
        boost::system::error_code ec;
        auto last_write_time = boost::filesystem::last_write_time(view->file_path, ec);
        if(last_write_time != last_write_time_)
          view->check_last_write_time(last_write_time);
        Recursive::f(view, last_write_time);
        return false;
      }, 1000);
    }
  };
  delayed_monitor_changed_connection.disconnect();
  if(this->last_write_time != static_cast<std::time_t>(-1))
    Recursive::f(this, last_write_time);
#else
  if(this->last_write_time != static_cast<std::time_t>(-1)) {
    monitor = Gio::File::create_for_path(file_path.string())->monitor_file(Gio::FileMonitorFlags::FILE_MONITOR_NONE);
    monitor_changed_connection.disconnect();
    monitor_changed_connection = monitor->signal_changed().connect([this](const Glib::RefPtr<Gio::File> &file,
                                                                          const Glib::RefPtr<Gio::File> &,
                                                                          Gio::FileMonitorEvent monitor_event) {
      if(monitor_event != Gio::FileMonitorEvent::FILE_MONITOR_EVENT_CHANGES_DONE_HINT) {
        delayed_monitor_changed_connection.disconnect();
        delayed_monitor_changed_connection = Glib::signal_timeout().connect([this]() {
          check_last_write_time();
          return false;
        }, 500);
      }
    });
  }
#endif
}

void Source::BaseView::check_last_write_time(std::time_t last_write_time_) {
  if(this->last_write_time == static_cast<std::time_t>(-1))
    return;

  if(Config::get().source.auto_reload_changed_files && !get_buffer()->get_modified()) {
    boost::system::error_code ec;
    auto last_write_time = last_write_time_ != static_cast<std::time_t>(-1) ? last_write_time_ : boost::filesystem::last_write_time(file_path, ec);
    if(!ec && last_write_time != this->last_write_time) {
      if(load())
        return;
    }
  }
  else if(has_focus()) {
    boost::system::error_code ec;
    auto last_write_time = last_write_time_ != static_cast<std::time_t>(-1) ? last_write_time_ : boost::filesystem::last_write_time(file_path, ec);
    if(!ec && last_write_time != this->last_write_time)
      Info::get().print("Caution: " + file_path.filename().string() + " was changed outside of juCi++");
  }
}

Gtk::TextIter Source::BaseView::get_iter_at_line_pos(int line, int pos) {
  return get_iter_at_line_index(line, pos);
}

Gtk::TextIter Source::BaseView::get_iter_at_line_offset(int line, int offset) {
  line = std::min(line, get_buffer()->get_line_count() - 1);
  if(line < 0)
    line = 0;
  auto iter = get_iter_at_line_end(line);
  offset = std::min(offset, iter.get_line_offset());
  if(offset < 0)
    offset = 0;
  return get_buffer()->get_iter_at_line_offset(line, offset);
}

Gtk::TextIter Source::BaseView::get_iter_at_line_index(int line, int index) {
  line = std::min(line, get_buffer()->get_line_count() - 1);
  if(line < 0)
    line = 0;
  auto iter = get_iter_at_line_end(line);
  index = std::min(index, iter.get_line_index());
  if(index < 0)
    index = 0;
  return get_buffer()->get_iter_at_line_index(line, index);
}

Gtk::TextIter Source::BaseView::get_iter_at_line_end(int line_nr) {
  if(line_nr >= get_buffer()->get_line_count())
    return get_buffer()->end();
  else if(line_nr + 1 < get_buffer()->get_line_count()) {
    auto iter = get_buffer()->get_iter_at_line(line_nr + 1);
    iter.backward_char();
    if(!iter.ends_line()) // for CR+LF
      iter.backward_char();
    return iter;
  }
  else {
    auto iter = get_buffer()->get_iter_at_line(line_nr);
    while(!iter.ends_line() && iter.forward_char()) {
    }
    return iter;
  }
}

Gtk::TextIter Source::BaseView::get_iter_for_dialog() {
  auto iter = get_buffer()->get_insert()->get_iter();
  Gdk::Rectangle visible_rect;
  get_visible_rect(visible_rect);
  Gdk::Rectangle iter_rect;
  get_iter_location(iter, iter_rect);
  iter_rect.set_width(1);
  if(iter.get_line_offset() >= 80) {
    get_iter_at_location(iter, visible_rect.get_x(), iter_rect.get_y());
    get_iter_location(iter, iter_rect);
  }
  if(!visible_rect.intersects(iter_rect))
    get_iter_at_location(iter, visible_rect.get_x(), visible_rect.get_y() + visible_rect.get_height() / 3);
  return iter;
}

void Source::BaseView::place_cursor_at_line_pos(int line, int pos) {
  get_buffer()->place_cursor(get_iter_at_line_pos(line, pos));
}

void Source::BaseView::place_cursor_at_line_offset(int line, int offset) {
  get_buffer()->place_cursor(get_iter_at_line_offset(line, offset));
}

void Source::BaseView::place_cursor_at_line_index(int line, int index) {
  get_buffer()->place_cursor(get_iter_at_line_index(line, index));
}

Gtk::TextIter Source::BaseView::get_smart_home_iter(const Gtk::TextIter &iter) {
  auto start_line_iter = get_buffer()->get_iter_at_line(iter.get_line());
  auto start_sentence_iter = start_line_iter;
  while(!start_sentence_iter.ends_line() &&
        (*start_sentence_iter == ' ' || *start_sentence_iter == '\t') &&
        start_sentence_iter.forward_char()) {
  }

  if(iter > start_sentence_iter || iter == start_line_iter)
    return start_sentence_iter;
  else
    return start_line_iter;
}

Gtk::TextIter Source::BaseView::get_smart_end_iter(const Gtk::TextIter &iter) {
  auto end_line_iter = get_iter_at_line_end(iter.get_line());
  auto end_sentence_iter = end_line_iter;
  while(!end_sentence_iter.starts_line() &&
        (*end_sentence_iter == ' ' || *end_sentence_iter == '\t' || end_sentence_iter.ends_line()) &&
        end_sentence_iter.backward_char()) {
  }
  if(!end_sentence_iter.ends_line() && *end_sentence_iter != ' ' && *end_sentence_iter != '\t')
    end_sentence_iter.forward_char();

  if(iter == end_line_iter)
    return end_sentence_iter;
  else
    return end_line_iter;
}

std::string Source::BaseView::get_line(const Gtk::TextIter &iter) {
  auto line_start_it = get_buffer()->get_iter_at_line(iter.get_line());
  auto line_end_it = get_iter_at_line_end(iter.get_line());
  std::string line(get_buffer()->get_text(line_start_it, line_end_it));
  return line;
}
std::string Source::BaseView::get_line(const Glib::RefPtr<Gtk::TextBuffer::Mark> &mark) {
  return get_line(mark->get_iter());
}
std::string Source::BaseView::get_line(int line_nr) {
  return get_line(get_buffer()->get_iter_at_line(line_nr));
}
std::string Source::BaseView::get_line() {
  return get_line(get_buffer()->get_insert());
}

std::string Source::BaseView::get_line_before(const Gtk::TextIter &iter) {
  auto line_it = get_buffer()->get_iter_at_line(iter.get_line());
  std::string line(get_buffer()->get_text(line_it, iter));
  return line;
}
std::string Source::BaseView::get_line_before(const Glib::RefPtr<Gtk::TextBuffer::Mark> &mark) {
  return get_line_before(mark->get_iter());
}
std::string Source::BaseView::get_line_before() {
  return get_line_before(get_buffer()->get_insert());
}

Gtk::TextIter Source::BaseView::get_tabs_end_iter(const Gtk::TextIter &iter) {
  return get_tabs_end_iter(iter.get_line());
}
Gtk::TextIter Source::BaseView::get_tabs_end_iter(const Glib::RefPtr<Gtk::TextBuffer::Mark> &mark) {
  return get_tabs_end_iter(mark->get_iter());
}
Gtk::TextIter Source::BaseView::get_tabs_end_iter(int line_nr) {
  auto sentence_iter = get_buffer()->get_iter_at_line(line_nr);
  while((*sentence_iter == ' ' || *sentence_iter == '\t') && !sentence_iter.ends_line() && sentence_iter.forward_char()) {
  }
  return sentence_iter;
}
Gtk::TextIter Source::BaseView::get_tabs_end_iter() {
  return get_tabs_end_iter(get_buffer()->get_insert());
}

void Source::BaseView::place_cursor_at_next_diagnostic() {
  auto insert_offset = get_buffer()->get_insert()->get_iter().get_offset();
  for(auto offset : diagnostic_offsets) {
    if(offset > insert_offset) {
      get_buffer()->place_cursor(get_buffer()->get_iter_at_offset(offset));
      scroll_to(get_buffer()->get_insert(), 0.0, 1.0, 0.5);
      return;
    }
  }
  if(diagnostic_offsets.size() == 0)
    Info::get().print("No diagnostics found in current buffer");
  else {
    auto iter = get_buffer()->get_iter_at_offset(*diagnostic_offsets.begin());
    get_buffer()->place_cursor(iter);
    scroll_to(get_buffer()->get_insert(), 0.0, 1.0, 0.5);
  }
}