#include <algorithm>
#include <map>
#include <random>

#include "absl/flags/flag.h"
#include "absl/strings/str_format.h"
#include <opencv2/calib3d.hpp>
#include <opencv2/features2d.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc.hpp>

#include "aos/events/shm_event_loop.h"
#include "aos/init.h"
#include "aos/time/time.h"
#include "frc971/vision/vision_generated.h"
#include "y2022/vision/blob_detector.h"
#include "y2022/vision/calibration_data.h"
#include "y2022/vision/camera_reader.h"
#include "y2022/vision/target_estimate_generated.h"
#include "y2022/vision/target_estimator.h"

ABSL_FLAG(std::string, capture, "",
          "If set, capture a single image and save it to this filename.");
ABSL_FLAG(std::string, channel, "/camera", "Channel name for the image.");
ABSL_FLAG(std::string, config, "aos_config.json",
          "Path to the config file to use.");
ABSL_FLAG(std::string, png_dir, "", "Path to a set of images to display.");
ABSL_FLAG(std::string, png_pattern, "*",
          R"(Pattern to match pngs using '*'/'?'.)");
ABSL_FLAG(std::string, calibration_node, "",
          "If reading locally, use the calibration for this node");
ABSL_FLAG(
    int32_t, calibration_team_number, 971,
    "If reading locally, use the calibration for a node with this team number");
ABSL_FLAG(uint64_t, skip, 0,
          "Number of images to skip if doing local reading (png_dir set).");
ABSL_FLAG(bool, show_features, true, "Show the blobs.");
ABSL_FLAG(bool, display_estimation, false,
          "If true, display the target estimation graphically");
ABSL_FLAG(bool, sort_by_time, true, "If true, sort the images by time");

namespace y2022::vision {
namespace {

using namespace frc971::vision;

std::map<int64_t, BlobDetector::BlobResult> target_est_map;
aos::Fetcher<frc971::vision::CameraImage> image_fetcher;
aos::Fetcher<y2022::vision::TargetEstimate> target_estimate_fetcher;

std::vector<cv::Point> FbsToCvPoints(
    const flatbuffers::Vector<const Point *> &points_fbs) {
  std::vector<cv::Point> points;
  for (const Point *point : points_fbs) {
    points.emplace_back(point->x(), point->y());
  }
  return points;
}

std::vector<std::vector<cv::Point>> FbsToCvBlobs(
    const flatbuffers::Vector<flatbuffers::Offset<Blob>> *blobs_fbs) {
  if (blobs_fbs == nullptr) {
    return {};
  }
  std::vector<std::vector<cv::Point>> blobs;
  for (const auto blob : *blobs_fbs) {
    blobs.emplace_back(FbsToCvPoints(*blob->points()));
  }
  return blobs;
}

std::vector<BlobDetector::BlobStats> FbsToBlobStats(
    const flatbuffers::Vector<flatbuffers::Offset<BlobStatsFbs>>
        &blob_stats_fbs) {
  std::vector<BlobDetector::BlobStats> blob_stats;
  for (const auto stats_fbs : blob_stats_fbs) {
    cv::Point centroid{stats_fbs->centroid()->x(), stats_fbs->centroid()->y()};
    cv::Size size{stats_fbs->size()->width(), stats_fbs->size()->height()};
    blob_stats.emplace_back(BlobDetector::BlobStats{
        centroid, size, stats_fbs->aspect_ratio(), stats_fbs->area(),
        static_cast<size_t>(stats_fbs->num_points())});
  }
  return blob_stats;
}

bool DisplayLoop() {
  int64_t target_timestamp = 0;
  if (target_estimate_fetcher.Fetch()) {
    const TargetEstimate *target_est = target_estimate_fetcher.get();
    CHECK(target_est != nullptr)
        << "Got null when trying to fetch target estimate";

    target_timestamp = target_est->image_monotonic_timestamp_ns();
    if (target_est->blob_result()->filtered_blobs()->size() > 0) {
      VLOG(2) << "Got blobs for timestamp " << target_est << "\n";
    }
    // Store the TargetEstimate data so we can match timestamp with image
    target_est_map[target_timestamp] = BlobDetector::BlobResult{
        cv::Mat(),
        FbsToCvBlobs(target_est->blob_result()->filtered_blobs()),
        FbsToCvBlobs(target_est->blob_result()->unfiltered_blobs()),
        FbsToBlobStats(*target_est->blob_result()->blob_stats()),
        FbsToBlobStats(*target_est->blob_result()->filtered_stats()),
        cv::Point{target_est->blob_result()->centroid()->x(),
                  target_est->blob_result()->centroid()->y()}};
    // Only keep last 10 matches
    while (target_est_map.size() > 10u) {
      target_est_map.erase(target_est_map.begin());
    }
  }
  int64_t image_timestamp = 0;
  if (!image_fetcher.Fetch()) {
    VLOG(2) << "Couldn't fetch image";
    return true;
  }
  const CameraImage *image = image_fetcher.get();
  CHECK(image != nullptr) << "Couldn't read image";
  image_timestamp = image->monotonic_timestamp_ns();
  VLOG(2) << "Got image at timestamp: " << image_timestamp;

  // Create color image:
  cv::Mat image_color_mat(cv::Size(image->cols(), image->rows()), CV_8UC2,
                          (void *)image->data()->data());
  cv::Mat bgr_image(cv::Size(image->cols(), image->rows()), CV_8UC3);
  cv::cvtColor(image_color_mat, bgr_image, cv::COLOR_YUV2BGR_YUYV);

  if (!absl::GetFlag(FLAGS_capture).empty()) {
    cv::imwrite(absl::GetFlag(FLAGS_capture), bgr_image);
    return false;
  }

  auto target_est_it = target_est_map.find(image_timestamp);
  if (target_est_it != target_est_map.end()) {
    LOG(INFO) << image->monotonic_timestamp_ns() << ": # unfiltered blobs: "
              << target_est_it->second.unfiltered_blobs.size()
              << "; # filtered blobs: "
              << target_est_it->second.filtered_blobs.size();

    cv::Mat ret_image =
        cv::Mat::zeros(cv::Size(image->cols(), image->rows()), CV_8UC3);
    BlobDetector::DrawBlobs(target_est_it->second, ret_image);
    cv::imshow("blobs", ret_image);
  }

  cv::imshow("image", bgr_image);

  int keystroke = cv::waitKey(1);
  if ((keystroke & 0xFF) == static_cast<int>('c')) {
    // Convert again, to get clean image
    cv::cvtColor(image_color_mat, bgr_image, cv::COLOR_YUV2BGR_YUYV);
    std::stringstream name;
    name << "capture-" << aos::realtime_clock::now() << ".png";
    cv::imwrite(name.str(), bgr_image);
    LOG(INFO) << "Saved image file: " << name.str();
  } else if ((keystroke & 0xFF) == static_cast<int>('q')) {
    return false;
  }
  return true;
}

void ViewerMain() {
  aos::FlatbufferDetachedBuffer<aos::Configuration> config =
      aos::configuration::ReadConfig(absl::GetFlag(FLAGS_config));

  aos::ShmEventLoop event_loop(&config.message());

  image_fetcher = event_loop.MakeFetcher<frc971::vision::CameraImage>(
      absl::GetFlag(FLAGS_channel));

  target_estimate_fetcher =
      event_loop.MakeFetcher<y2022::vision::TargetEstimate>(
          absl::GetFlag(FLAGS_channel));

  // Run the display loop
  event_loop.AddPhasedLoop(
      [&event_loop](int) {
        if (!DisplayLoop()) {
          LOG(INFO) << "Calling event_loop Exit";
          event_loop.Exit();
        };
      },
      ::std::chrono::milliseconds(100));

  event_loop.Run();
}

size_t FindImageTimestamp(std::string_view filename) {
  // Find the first number in the string
  const auto timestamp_start = std::find_if(
      filename.begin(), filename.end(), [](char c) { return std::isdigit(c); });
  CHECK_NE(timestamp_start, filename.end())
      << "Expected a number in image filename, got " << filename;
  const auto timestamp_end =
      std::find_if_not(timestamp_start + 1, filename.end(),
                       [](char c) { return std::isdigit(c); });

  return static_cast<size_t>(
      std::atoi(filename
                    .substr(timestamp_start - filename.begin(),
                            timestamp_end - timestamp_start)
                    .data()));
}

void ViewerLocal() {
  std::vector<cv::String> file_list;
  cv::glob(absl::StrFormat("%s/%s.png", absl::GetFlag(FLAGS_png_dir),
                           absl::GetFlag(FLAGS_png_pattern)),
           file_list, false);

  // Sort the images by timestamp
  if (absl::GetFlag(FLAGS_sort_by_time)) {
    std::sort(file_list.begin(), file_list.end(),
              [](std::string_view filename_1, std::string_view filename_2) {
                return (FindImageTimestamp(filename_1) <
                        FindImageTimestamp(filename_2));
              });
  }

  const aos::FlatbufferSpan<calibration::CalibrationData> calibration_data(
      CalibrationData());

  const calibration::CameraCalibration *calibration =
      CameraReader::FindCameraCalibration(
          &calibration_data.message(), absl::GetFlag(FLAGS_calibration_node),
          absl::GetFlag(FLAGS_calibration_team_number));
  const auto intrinsics = CameraReader::CameraIntrinsics(calibration);
  const auto extrinsics = CameraReader::CameraExtrinsics(calibration);
  const auto dist_coeffs = CameraReader::CameraDistCoeffs(calibration);

  // Compute undistortion map once for efficiency
  const auto undistort_maps =
      CameraReader::ComputeUndistortMaps(intrinsics, dist_coeffs);

  TargetEstimator estimator(intrinsics, extrinsics);

  for (auto it = file_list.begin() + absl::GetFlag(FLAGS_skip);
       it < file_list.end(); it++) {
    LOG(INFO) << "Reading file " << (it - file_list.begin()) << ": " << *it;
    cv::Mat image_mat =
        CameraReader::UndistortImage(cv::imread(it->c_str()), undistort_maps);

    BlobDetector::BlobResult blob_result;
    blob_result.binarized_image =
        cv::Mat::zeros(cv::Size(image_mat.cols, image_mat.rows), CV_8UC1);
    BlobDetector::ExtractBlobs(image_mat, &blob_result);

    cv::Mat ret_image =
        cv::Mat::zeros(cv::Size(image_mat.cols, image_mat.rows), CV_8UC3);
    BlobDetector::DrawBlobs(blob_result, ret_image);

    LOG(INFO) << ": # blobs: " << blob_result.filtered_blobs.size()
              << " (# removed: "
              << blob_result.unfiltered_blobs.size() -
                     blob_result.filtered_blobs.size()
              << ")";

    estimator.Solve(blob_result.filtered_stats,
                    absl::GetFlag(FLAGS_display_estimation)
                        ? std::make_optional(ret_image)
                        : std::nullopt);
    if (blob_result.filtered_blobs.size() > 0) {
      estimator.DrawEstimate(ret_image);
      LOG(INFO) << "Read file " << (it - file_list.begin()) << ": " << *it;
    }

    cv::imshow("image", image_mat);
    cv::imshow("mask", blob_result.binarized_image);
    cv::imshow("blobs", ret_image);

    constexpr size_t kWaitKeyDelay = 0;  // ms
    int keystroke = cv::waitKey(kWaitKeyDelay) & 0xFF;
    // Ignore alt key
    while (keystroke == 233) {
      keystroke = cv::waitKey(kWaitKeyDelay);
    }
    if (keystroke == static_cast<int>('q')) {
      return;
    }
  }
}
}  // namespace
}  // namespace y2022::vision

// Quick and lightweight viewer for images
int main(int argc, char **argv) {
  aos::InitGoogle(&argc, &argv);
  if (absl::GetFlag(FLAGS_png_dir) != "")
    y2022::vision::ViewerLocal();
  else
    y2022::vision::ViewerMain();
}