#include <algorithm>

#include <vamp_zero/navigation.hpp>


auto vamp_zero::selected_group(vamp_zero::app_state const &state) -> vamp_zero::song_group const * {
  if (state.selected_song_index == 0U || state.catalog->groups.empty()) {
    return nullptr;
  }
  auto index = state.selected_song_index - 1U;
  if (index >= state.catalog->groups.size()) {
    return nullptr;
  }
  return &state.catalog->groups[index];
}

auto vamp_zero::selected_part(vamp_zero::app_state const &state) -> vamp_zero::library_part const * {
  auto const *group = vamp_zero::selected_group(state);
  if (state.selected_part_index == 0U || group == nullptr || group->parts.empty()) {
    return nullptr;
  }
  auto index = state.selected_part_index - 1U;
  if (index >= group->parts.size()) {
    return nullptr;
  }
  auto part_index = group->parts[index];
  return part_index < state.catalog->parts.size() ? &state.catalog->parts[part_index] : nullptr;
}

auto vamp_zero::active_part(vamp_zero::app_state const &state) -> vamp_zero::library_part const * {
  if (state.active_part_id.empty()) {
    return nullptr;
  }
  auto found = std::find_if(state.catalog->parts.begin(), state.catalog->parts.end(), [&](auto const &part) {
    return part.id == state.active_part_id;
  });
  return found == state.catalog->parts.end() ? nullptr : &*found;
}

auto vamp_zero::active_pages(vamp_zero::app_state const &state) -> std::size_t {
  if (state.mode == vamp_zero::app_mode::PERFORMANCE_SCORE) {
    auto const *part = vamp_zero::active_part(state);
    return part == nullptr ? 0U : part->total_pages;
  }
  return 0U;
}