// ----------------------------------------------------------------------------
// -                        Open3D: www.open3d.org                            -
// ----------------------------------------------------------------------------
// Copyright (c) 2018-2023 www.open3d.org
// SPDX-License-Identifier: MIT
// ----------------------------------------------------------------------------

#include "open3d/visualization/visualizer/ViewControlWithCustomAnimation.h"

#include "open3d/io/IJsonConvertibleIO.h"
#include "open3d/utility/Helper.h"
#include "open3d/utility/Logging.h"

namespace open3d {
namespace visualization {

void ViewControlWithCustomAnimation::Reset() {
    if (animation_mode_ == AnimationMode::FreeMode) {
        ViewControl::Reset();
    }
}

void ViewControlWithCustomAnimation::ChangeFieldOfView(double step) {
    if (animation_mode_ == AnimationMode::FreeMode) {
        if (!view_trajectory_.view_status_.empty()) {
            // Once editing starts, lock ProjectionType.
            // This is because ProjectionType cannot be easily switched in a
            // smooth trajectory.
            if (GetProjectionType() == ProjectionType::Perspective) {
                double old_fov = field_of_view_;
                ViewControl::ChangeFieldOfView(step);
                if (GetProjectionType() == ProjectionType::Orthogonal) {
                    field_of_view_ = old_fov;
                }
            } else {
                // do nothing, lock as ProjectionType::Orthogonal
            }
            SetProjectionParameters();
        } else {
            ViewControl::ChangeFieldOfView(step);
        }
    }
}

void ViewControlWithCustomAnimation::Scale(double scale) {
    if (animation_mode_ == AnimationMode::FreeMode) {
        ViewControl::Scale(scale);
    }
}

void ViewControlWithCustomAnimation::Rotate(double x,
                                            double y,
                                            double xo,
                                            double yo) {
    if (animation_mode_ == AnimationMode::FreeMode) {
        ViewControl::Rotate(x, y, xo, yo);
    }
}

void ViewControlWithCustomAnimation::Translate(double x,
                                               double y,
                                               double xo,
                                               double yo) {
    if (animation_mode_ == AnimationMode::FreeMode) {
        ViewControl::Translate(x, y, xo, yo);
    }
}

void ViewControlWithCustomAnimation::SetAnimationMode(AnimationMode mode) {
    if (mode != AnimationMode::FreeMode &&
        view_trajectory_.view_status_.empty()) {
        return;
    }
    animation_mode_ = mode;
    switch (mode) {
        case AnimationMode::PreviewMode:
        case AnimationMode::PlayMode:
            view_trajectory_.ComputeInterpolationCoefficients();
            GoToFirst();
            break;
        case AnimationMode::FreeMode:
        default:
            break;
    }
}

void ViewControlWithCustomAnimation::AddKeyFrame() {
    if (animation_mode_ == AnimationMode::FreeMode) {
        ViewParameters current_status;
        ConvertToViewParameters(current_status);
        if (view_trajectory_.view_status_.empty()) {
            view_trajectory_.view_status_.push_back(current_status);
            current_keyframe_ = 0.0;
        } else {
            size_t current_index = CurrentKeyframe();
            view_trajectory_.view_status_.insert(
                    view_trajectory_.view_status_.begin() + current_index + 1,
                    current_status);
            current_keyframe_ = current_index + 1.0;
        }
    }
}

void ViewControlWithCustomAnimation::UpdateKeyFrame() {
    if (animation_mode_ == AnimationMode::FreeMode &&
        !view_trajectory_.view_status_.empty()) {
        ConvertToViewParameters(
                view_trajectory_.view_status_[CurrentKeyframe()]);
    }
}

void ViewControlWithCustomAnimation::DeleteKeyFrame() {
    if (animation_mode_ == AnimationMode::FreeMode &&
        !view_trajectory_.view_status_.empty()) {
        size_t current_index = CurrentKeyframe();
        view_trajectory_.view_status_.erase(
                view_trajectory_.view_status_.begin() + current_index);
        current_keyframe_ = RegularizeFrameIndex(
                current_index - 1.0, view_trajectory_.view_status_.size(),
                view_trajectory_.is_loop_);
    }
    SetViewControlFromTrajectory();
}

void ViewControlWithCustomAnimation::AddSpinKeyFrames(int num_of_key_frames
                                                      /* = 20*/) {
    if (animation_mode_ == AnimationMode::FreeMode) {
        double radian_per_step = M_PI * 2.0 / double(num_of_key_frames);
        for (int i = 0; i < num_of_key_frames; i++) {
            ViewControl::Rotate(radian_per_step / ROTATION_RADIAN_PER_PIXEL, 0);
            AddKeyFrame();
        }
    }
}

std::string ViewControlWithCustomAnimation::GetStatusString() const {
    std::string prefix;
    switch (animation_mode_) {
        case AnimationMode::FreeMode:
            prefix = "Editing ";
            break;
        case AnimationMode::PreviewMode:
            prefix = "Previewing ";
            break;
        case AnimationMode::PlayMode:
            prefix = "Playing ";
            break;
    }
    std::string buffer;
    if (animation_mode_ == AnimationMode::FreeMode) {
        if (view_trajectory_.view_status_.empty()) {
            buffer = "empty trajectory";
        } else {
            buffer = fmt::format(
                    "#{} keyframe ({} in total{})",
                    (unsigned int)CurrentKeyframe() + 1,
                    (unsigned int)view_trajectory_.view_status_.size(),
                    view_trajectory_.is_loop_ ? ", looped" : "");
        }
    } else {
        if (view_trajectory_.view_status_.empty()) {
            buffer = "empty trajectory";
        } else {
            buffer = fmt::format(buffer, "#{} frame ({} in total{})",
                                 (unsigned int)CurrentFrame() + 1,
                                 (unsigned int)view_trajectory_.NumOfFrames(),
                                 view_trajectory_.is_loop_ ? ", looped" : "");
        }
    }
    return prefix + std::string(buffer);
}

void ViewControlWithCustomAnimation::Step(double change) {
    if (view_trajectory_.view_status_.empty()) {
        return;
    }
    if (animation_mode_ == AnimationMode::FreeMode) {
        current_keyframe_ += change;
        current_keyframe_ = RegularizeFrameIndex(
                current_keyframe_, view_trajectory_.view_status_.size(),
                view_trajectory_.is_loop_);
    } else {
        current_frame_ += change;
        current_frame_ = RegularizeFrameIndex(current_frame_,
                                              view_trajectory_.NumOfFrames(),
                                              view_trajectory_.is_loop_);
    }
    SetViewControlFromTrajectory();
}

void ViewControlWithCustomAnimation::GoToFirst() {
    if (view_trajectory_.view_status_.empty()) {
        return;
    }
    if (animation_mode_ == AnimationMode::FreeMode) {
        current_keyframe_ = 0.0;
    } else {
        current_frame_ = 0.0;
    }
    SetViewControlFromTrajectory();
}

void ViewControlWithCustomAnimation::GoToLast() {
    if (view_trajectory_.view_status_.empty()) {
        return;
    }
    if (animation_mode_ == AnimationMode::FreeMode) {
        current_keyframe_ = view_trajectory_.view_status_.size() - 1.0;
    } else {
        current_frame_ = view_trajectory_.NumOfFrames() - 1.0;
    }
    SetViewControlFromTrajectory();
}

bool ViewControlWithCustomAnimation::CaptureTrajectory(
        const std::string &filename /* = ""*/) {
    if (view_trajectory_.view_status_.empty()) {
        return false;
    }
    std::string json_filename = filename;
    if (json_filename.empty()) {
        json_filename =
                "ViewTrajectory_" + utility::GetCurrentTimeStamp() + ".json";
    }
    utility::LogDebug("[Visualizer] Trejactory capture to {}",
                      json_filename.c_str());
    return io::WriteIJsonConvertible(json_filename, view_trajectory_);
}

bool ViewControlWithCustomAnimation::LoadTrajectoryFromJsonFile(
        const std::string &filename) {
    bool success = io::ReadIJsonConvertible(filename, view_trajectory_);
    if (!success) {
        view_trajectory_.Reset();
    }
    current_keyframe_ = 0.0;
    current_frame_ = 0.0;
    SetViewControlFromTrajectory();
    return success;
}

bool ViewControlWithCustomAnimation::LoadTrajectoryFromCameraTrajectory(
        const camera::PinholeCameraTrajectory &camera_trajectory) {
    current_keyframe_ = 0.0;
    current_frame_ = 0.0;
    view_trajectory_.Reset();
    if (camera_trajectory.parameters_.empty()) {
        return false;
    }
    view_trajectory_.interval_ = ViewTrajectory::INTERVAL_MIN;
    view_trajectory_.is_loop_ = false;
    view_trajectory_.view_status_.resize(camera_trajectory.parameters_.size());
    for (size_t i = 0; i < camera_trajectory.parameters_.size(); i++) {
        ViewControlWithCustomAnimation view_control = *this;
        if (!view_control.ConvertFromPinholeCameraParameters(
                    camera_trajectory.parameters_[i])) {
            view_trajectory_.Reset();
            return false;
        }
        if (!view_control.ConvertToViewParameters(
                    view_trajectory_.view_status_[i])) {
            view_trajectory_.Reset();
            return false;
        }
    }
    SetViewControlFromTrajectory();
    return true;
}

bool ViewControlWithCustomAnimation::IsValidPinholeCameraTrajectory() const {
    if (view_trajectory_.view_status_.empty()) {
        return false;
    }
    if (view_trajectory_.view_status_[0].field_of_view_ == FIELD_OF_VIEW_MIN) {
        return false;
    }
    for (const auto &status : view_trajectory_.view_status_) {
        if (status.field_of_view_ !=
            view_trajectory_.view_status_[0].field_of_view_) {
            return false;
        }
    }
    return true;
}

double ViewControlWithCustomAnimation::RegularizeFrameIndex(
        double current_frame, size_t num_of_frames, bool is_loop) {
    if (num_of_frames == 0) {
        return 0.0;
    }
    double frame_index = current_frame;
    if (is_loop) {
        while (int(round(frame_index)) < 0) {
            frame_index += double(num_of_frames);
        }
        while (int(round(frame_index)) >= int(num_of_frames)) {
            frame_index -= double(num_of_frames);
        }
    } else {
        if (frame_index < 0.0) {
            frame_index = 0.0;
        }
        if (frame_index > num_of_frames - 1.0) {
            frame_index = num_of_frames - 1.0;
        }
    }
    return frame_index;
}

void ViewControlWithCustomAnimation::SetViewControlFromTrajectory() {
    if (view_trajectory_.view_status_.empty()) {
        return;
    }
    if (animation_mode_ == AnimationMode::FreeMode) {
        ConvertFromViewParameters(
                view_trajectory_.view_status_[CurrentKeyframe()]);
    } else {
        bool success;
        ViewParameters status;
        std::tie(success, status) =
                view_trajectory_.GetInterpolatedFrame(CurrentFrame());
        if (success) {
            ConvertFromViewParameters(status);
        }
    }
}

}  // namespace visualization
}  // namespace open3d