// Copyright 2025 Enactic, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <atomic>
#include <chrono>
#include <controller/control.hpp>
#include <controller/dynamics.hpp>
#include <csignal>
#include <filesystem>
#include <iostream>
#include <openarm/can/socket/openarm.hpp>
#include <openarm/damiao_motor/dm_motor_constants.hpp>
#include <linux/can.h>
#include <linux/can/raw.h>
#include <net/if.h>
#include <openarm_port/openarm_init.hpp>
#include <periodic_timer_thread.hpp>
#include <poll.h>
#include <robot_state.hpp>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <thread>
#include <unistd.h>
#include <yamlloader.hpp>

std::atomic<bool> keep_running(true);
std::atomic<double> sensor_angle_rad(0.0);
std::atomic<double> sensor_velocity_rad_s(0.0);
std::atomic<bool> sensor_angle_ready(false);

constexpr canid_t SENSOR_CAN_ID = 0x01;  // TODO: replace with your sensor CAN ID
constexpr double SENSOR_SCALE = 1e-3;     // TODO: replace with your sensor scaling
constexpr double SENSOR_OFFSET = 0.0;
constexpr double SENSOR_FILTER_ALPHA = 0.05;  // 0~1, larger = less smoothing
constexpr double SENSOR_VEL_FILTER_ALPHA = 0.2;  // 0~1, larger = less smoothing

int open_can_socket(const std::string &can_interface) {
    int sock = socket(PF_CAN, SOCK_RAW, CAN_RAW);
    if (sock < 0) {
        throw std::runtime_error("Failed to open CAN socket");
    }

    struct ifreq ifr;
    std::snprintf(ifr.ifr_name, IFNAMSIZ, "%s", can_interface.c_str());
    if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0) {
        close(sock);
        throw std::runtime_error("Failed to get CAN interface index");
    }

    struct sockaddr_can addr;
    std::memset(&addr, 0, sizeof(addr));
    addr.can_family = AF_CAN;
    addr.can_ifindex = ifr.ifr_ifindex;

    if (bind(sock, reinterpret_cast<struct sockaddr *>(&addr), sizeof(addr)) < 0) {
        close(sock);
        throw std::runtime_error("Failed to bind CAN socket");
    }

    struct can_filter filter;
    filter.can_id = SENSOR_CAN_ID;
    filter.can_mask = CAN_SFF_MASK;
    if (setsockopt(sock, SOL_CAN_RAW, CAN_RAW_FILTER, &filter, sizeof(filter)) < 0) {
        close(sock);
        throw std::runtime_error("Failed to set CAN filter");
    }

    return sock;
}

bool read_sensor(int sock, double &angle_rad_out, double &velocity_rad_s_out) {
    struct pollfd pfd;
    pfd.fd = sock;
    pfd.events = POLLIN;
    int ret = poll(&pfd, 1, 10);
    if (ret <= 0 || !(pfd.revents & POLLIN)) {
        return false;
    }

    struct can_frame frame;
    int nbytes = read(sock, &frame, sizeof(frame));
    if (nbytes != static_cast<int>(sizeof(frame))) {
        return false;
    }

    const canid_t frame_id = frame.can_id & CAN_SFF_MASK;
    if (frame_id != SENSOR_CAN_ID || frame.can_dlc < 4) {
        return false;
    }

    int32_t rawPos = 0;
    rawPos |= static_cast<int32_t>(frame.data[1]) << 8;
    rawPos |= static_cast<int32_t>(frame.data[2]);
    int16_t rawVel = 0;
    rawVel |= static_cast<int32_t>(frame.data[3]) << 8;
    rawVel |= static_cast<int32_t>(frame.data[4]);

    velocity_rad_s_out = (static_cast<double>(rawVel) / 100.0 / 4096.0) * 360.0 * (M_PI / 180.0);  // Example conversion, adjust as needed

    angle_rad_out = (static_cast<double>(rawPos) / 4096.0) * 360.0;  // Example conversion, adjust as needed
    angle_rad_out = angle_rad_out * (M_PI / 180.0) - 3.14;
    return true;
}

void signal_handler(int signal) {
    if (signal == SIGINT) {
        std::cout << "\nCtrl+C detected. Exiting loop..." << std::endl;
        keep_running = false;
    }
}

class FollowerArmThread : public PeriodicTimerThread {
public:
    FollowerArmThread(std::shared_ptr<RobotSystemState> robot_state, Control *control_f,
                      double hz = 500.0)
        : PeriodicTimerThread(hz), robot_state_(robot_state), control_f_(control_f) {}

protected:
    void before_start() override { std::cout << "follower start thread " << std::endl; }

    void after_stop() override { std::cout << "follower stop thread " << std::endl; }

    void on_timer() override {
        static auto prev_time = std::chrono::steady_clock::now();
        if (sensor_angle_ready.load()) {
            // control_f_->SetArmJointReference(0, 0, 0.01);
            control_f_->SetArmJointReference(0, sensor_angle_rad.load(),
                                             sensor_velocity_rad_s.load());
            std::cout << "Sensor angle (rad): " << sensor_angle_rad.load() << std::endl;
            std::cout << "Sensor velocity (rad/s): " << sensor_velocity_rad_s.load() << std::endl;
        }
        // control_f_->SetArmJointReference(0, 0.2, 0.01);  // Example: set joint 0 to 0 radians
        
        control_f_->unilateral_step();

        auto now = std::chrono::steady_clock::now();

        auto elapsed_us =
            std::chrono::duration_cast<std::chrono::microseconds>(now - prev_time).count();
        prev_time = now;
        // std::cout << "Leader joint 0 position: " << robot_state_->arm_state().get_reference(0).position
        //           << std::endl;
        // std::cout << "Leader joint 0 velocity: " << robot_state_->arm_state().get_reference(0).velocity
        //           << std::endl;
        // std::cout << "[Follower] Period: " << elapsed_us << " us" << std::endl;
    }

private:
    std::shared_ptr<RobotSystemState> robot_state_;
    Control *control_f_;
};


int main(int argc, char **argv) {
    try {
        std::signal(SIGINT, signal_handler);

        // default configration
        std::string arm_side = "right_arm";
        std::string leader_urdf_path;
        std::string follower_urdf_path;
        std::string follower_can_interface = "can2";
        std::string sensor_can_interface = "can0";

        if (argc < 3) {
            std::cerr
                << "Usage: " << argv[0]
                     << " <leader_urdf_path> <follower_urdf_path> [arm_side] [leader_can] [follower_can]"
                << std::endl;
            return 1;
        }

        // Required: URDF paths
        leader_urdf_path = argv[1];
        follower_urdf_path = argv[2];

        // Optional: arm_side
        if (argc >= 4) {
            arm_side = argv[3];
            if (arm_side != "left_arm" && arm_side != "right_arm") {
                std::cerr << "[ERROR] Invalid arm_side: " << arm_side
                          << ". Must be 'left_arm' or 'right_arm'." << std::endl;
                return 1;
            }
        }

        // Optional: CAN interfaces
        if (argc >= 6) {
            follower_can_interface = argv[5];
        }

        // Optional: sensor CAN interface
        if (argc >= 7) {
            sensor_can_interface = argv[6];
        }

        // URDF file existence check
        if (!std::filesystem::exists(leader_urdf_path)) {
            std::cerr << "[ERROR] Leader URDF not found: " << leader_urdf_path << std::endl;
            return 1;
        }
        if (!std::filesystem::exists(follower_urdf_path)) {
            std::cerr << "[ERROR] Follower URDF not found: " << follower_urdf_path << std::endl;
            return 1;
        }

        // Setup dynamics
        std::string root_link = "openarm_body_link0";
        std::string leaf_link =
            (arm_side == "left_arm") ? "openarm_left_hand" : "openarm_right_hand";

        // Output confirmation
        std::cout << "=== OpenArm Unilateral Control ===" << std::endl;
        std::cout << "Arm side         : " << arm_side << std::endl;
        std::cout << "Follower CAN     : " << follower_can_interface << std::endl;
        std::cout << "Leader URDF path : " << leader_urdf_path << std::endl;
        std::cout << "Follower URDF path: " << follower_urdf_path << std::endl;
        std::cout << "Root link         : " << root_link << std::endl;
        std::cout << "Leaf link         : " << leaf_link << std::endl;
        std::cout << "Sensor CAN        : " << sensor_can_interface << std::endl;

        int sensor_can_socket = open_can_socket(sensor_can_interface);
        std::thread can_read_thread([&]() {
            double filtered_angle = 0.0;
            bool filter_initialized = false;
            double filtered_velocity = 0.0;
            double prev_angle = 0.0;
            auto prev_time = std::chrono::steady_clock::now();
            double velocity = 0.0;
            while (keep_running) {
                double angle = 0.0;
                if (read_sensor(sensor_can_socket,  angle, velocity)) {
                    auto now = std::chrono::steady_clock::now();
                    double dt =
                        std::chrono::duration_cast<std::chrono::duration<double>>(now - prev_time)
                            .count();
                    // std::cout << "dt: " << dt << " s, raw angle: " << angle << " rad" << std::endl;
                    prev_time = now;

                    if (!filter_initialized) {
                        filtered_angle = angle;
                        filter_initialized = true;
                        prev_angle = angle;
                        filtered_velocity = 0.0;
                    } else {
                        filtered_angle = SENSOR_FILTER_ALPHA * angle +
                                         (1.0 - SENSOR_FILTER_ALPHA) * filtered_angle;

                        if (dt > 1e-6) {
                            filtered_velocity = SENSOR_VEL_FILTER_ALPHA * velocity +
                                                (1.0 - SENSOR_VEL_FILTER_ALPHA) *
                                                    filtered_velocity;
                        }
                        prev_angle = angle;
                    }
                    sensor_angle_rad.store(filtered_angle);
                    sensor_velocity_rad_s.store(filtered_velocity);
                    sensor_angle_ready.store(true);
                }
            }
        });

        YamlLoader leader_loader("/home/shen/openarm_ros2_ws/src/openarm_teleop/config/leader.yaml");
        YamlLoader follower_loader("/home/shen/openarm_ros2_ws/src/openarm_teleop/config/follower.yaml");

        // Follower parameters
        std::vector<double> follower_kp = follower_loader.get_vector("FollowerArmParam", "Kp");
        std::vector<double> follower_kd = follower_loader.get_vector("FollowerArmParam", "Kd");
        std::vector<double> follower_Fc = follower_loader.get_vector("FollowerArmParam", "Fc");
        std::vector<double> follower_k = follower_loader.get_vector("FollowerArmParam", "k");
        std::vector<double> follower_Fv = follower_loader.get_vector("FollowerArmParam", "Fv");
        std::vector<double> follower_Fo = follower_loader.get_vector("FollowerArmParam", "Fo");

        Dynamics *leader_arm_dynamics = new Dynamics(leader_urdf_path, root_link, leaf_link);
        leader_arm_dynamics->Init();

        Dynamics *follower_arm_dynamics = new Dynamics(follower_urdf_path, root_link, leaf_link);
        follower_arm_dynamics->Init();

        std::cout << "=== Initializing Follower OpenArm ===" << std::endl;
        openarm::can::socket::OpenArm *follower_openarm =
            openarm_init::OpenArmInitializer::initialize_openarm(follower_can_interface, true);

        size_t follower_arm_motor_num = follower_openarm->get_arm().get_motors().size();
        size_t follower_hand_motor_num = follower_openarm->get_gripper().get_motors().size();

        std::cout << "follower arm motor num : " << follower_arm_motor_num << std::endl;
        std::cout << "follower hand motor num : " << follower_hand_motor_num << std::endl;

        // Declare robot_state (Joint and motor counts are assumed to be equal)

        std::shared_ptr<RobotSystemState> follower_state =
            std::make_shared<RobotSystemState>(follower_arm_motor_num, follower_hand_motor_num);

        Control *control_follower =
            new Control(follower_openarm, leader_arm_dynamics, follower_arm_dynamics,
                        follower_state, 1.0 / FREQUENCY, ROLE_FOLLOWER, arm_side,
                        follower_arm_motor_num, follower_hand_motor_num);

        control_follower->SetParameter(follower_kp, follower_kd, follower_Fc, follower_k,
                                       follower_Fv, follower_Fo);

        // set home postion
        // std::thread thread_l(&Control::AdjustPosition, control_leader);
        // std::thread thread_f(&Control::AdjustPosition, control_follower);
        // thread_l.join();
        // thread_f.join();

        // Start control process
        FollowerArmThread follower_thread(follower_state, control_follower, FREQUENCY);

        follower_thread.start_thread();

        while (keep_running) {
            std::this_thread::sleep_for(std::chrono::milliseconds(1000));
        }

        follower_thread.stop_thread();

        follower_openarm->disable_all();

        if (can_read_thread.joinable()) {
            can_read_thread.join();
        }
        close(sensor_can_socket);

    } catch (const std::exception &e) {
        std::cerr << e.what() << '\n';
    }

    return 0;
}