#include <chrono>
#include <csignal>
#include <functional>
#include <mutex>
#include <semaphore>
#include <stop_token>
#include <string>
#include <thread>
#include <vector>
// local includes
#include <LCDDisplay.hpp>
#include <cpu.hpp>
#include <gpu.hpp>
#include <hass.hpp>
#include <log.hpp>
#include <sys.hpp>
#include <utils.hpp>

#define LCD_PORT "/dev/serial/by-id/usb-Raspberry_Pi_Pico_E6616407E37AA12F-if00"  // tis a symlink, can also be just /dev/ttyACM0
#define LCD_INTERVAL_MS 500
#define LCD_CONTRAST 215

/* these need to be global since we're talking to them from sighandler */

namespace sem {
std::binary_semaphore display{0};
std::binary_semaphore main{0};
}  // namespace sem

// maybe put semaphores in the struct?
struct Sensors {
    sys::TimeDate td;
    double avg[3] = {0.0f};
    sys::Memory ram;
    sys::Disk home;
    sys::Network net;
    sys::sysSensors sys;
    cpu::cpuSensors cpu;
    gpu::gpuSensors gpu;
    float hass_state = 0.0f;
    std::mutex mtx;  // making sure the struct isnt accessed by multiple threads at once
};

void sighandler(int) {
    log(LOG::WRN, "Signal", "got SIGINT/SIGTERM, exiting...");
    sem::main.release();
    sem::display.release();
}

void hassThread(std::stop_token st, Sensors* s) {
    log(LOG::INF, "Thread", "Starting hass_thread");
    HomeAssistant pc_power("home.drath.win", "sensor.gniazdko_komputer_moc");

    pc_power.connect();
    while (!st.stop_requested()) {
        pc_power.service();
        {
            // locks mutex for the lifetime of the scope, unlocks when it goes out of scope
            // mutex can only be locked in one place, so when its locked here, other threads need to wait until its unlocked before they can lock it again
            std::lock_guard<std::mutex> lock(s->mtx);
            s->hass_state = pc_power.state;
        }
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
}

void sensorsThread(std::stop_token st, Sensors* s) {
    log(LOG::INF, "Thread", "Starting sensors_thread, poll interval {} ms", LCD_INTERVAL_MS);
    cpu::detectHwmon(&s->cpu, "0000:00:18.3");
    gpu::detectHwmon(&s->gpu, "0000:0b:00.0");
    sys::detectHwmon(&s->sys, "nct6775.656");
    s->home.mountpoint = "/home/drath";

    while (!st.stop_requested()) {
        auto start = std::chrono::steady_clock::now();
        {
            std::lock_guard<std::mutex> lock(s->mtx);

            sys::getTimeDate(&s->td);
            getloadavg(s->avg, 3);
            sys::getRam(&s->ram);
            sys::getDisk(&s->home);
            sys::getNetwork(&s->net, "enp4s0f0");
            sys::updateSensors(&s->sys);
            cpu::update(&s->cpu);
            gpu::update(&s->gpu);
        }

        // log(LOG::DBG, "Sensors", "took {} microseconds", std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::steady_clock::now() - start).count());
        sem::display.release();  // unlocks display loop
        std::this_thread::sleep_until(start + std::chrono::milliseconds(LCD_INTERVAL_MS));
    }
}

void displayThread(std::stop_token st, Sensors* s) {
    log(LOG::INF, "Thread", "Starting display_thread");
    // init internal variables of LCDDisplay class
    LCDDisplay lcd(LCD_PORT);

    // basic lcd setup
    lcd.setContrast(LCD_CONTRAST);
    lcd.setBacklight(true);
    lcd.setCustomChar(0, {16, 6, 9, 8, 8, 9, 6, 0});     // celcius
    lcd.setCustomChar(1, {0, 0, 4, 10, 10, 17, 31, 0});  // delta
    lcd.setCustomChar(2, {0, 0, 8, 21, 21, 2, 0, 0});    // home (tilde)
    lcd.setCustomChar(3, {4, 14, 21, 4, 4, 4 , 0});      // up arrow
    lcd.setCustomChar(4, {4, 4, 4, 21, 14, 4 , 0});      // down arrow

    // welcome msg
    lcd.writeBuf(2, 0, center("Waiting for sensors...", 40));
    lcd.flushBuf();
    lcd.clearBuf();

    // actual main display loop
    while (!st.stop_requested()) {
        sem::display.acquire();  // holds the loop until sensor data is ready
        {
            std::lock_guard<std::mutex> lock(s->mtx);

            // prepare some tricky sensors
            std::string gpu_temps = std::to_string(s->gpu.temp_edge);
            if (s->gpu.temp_hotspot)
                gpu_temps = pad(lcd.cc(1) + std::to_string(s->gpu.temp_hotspot - s->gpu.temp_edge) + lcd.cc(0), 4) + " " + pad(gpu_temps + "/" + std::to_string(s->gpu.temp_hotspot), 5);

            uint16_t cpu_fan = 0;
            for (auto &fan : s->sys.fan_speed)
                cpu_fan += fan;
            cpu_fan /= 2;
            
            // write to display buffer
            lcd.writeBuf(0, 0, pad(s->td.date, 11, JUST::LEFT) + "   " + s->td.time + lcd.bar(7, s->gpu.usage_core / 100.0));
            lcd.writeBuf(0, 26, pNum(s->avg[0], s->avg[0] > 10 ? 1 : 2));
            lcd.writeBuf(0, 31, pNum(s->avg[1], s->avg[1] > 10 ? 1 : 2));
            lcd.writeBuf(0, 36, pNum(s->avg[2], s->avg[2] > 10 ? 1 : 2));

            lcd.writeBuf(1, 0, pad(std::to_string(s->cpu.tctl) + "/" + std::to_string(s->cpu.tccd1) + lcd.cc(0), 8, JUST::LEFT));
            lcd.writeBuf(1, 7, pad(pBytes(s->ram.used, true), 6, JUST::LEFT));
            lcd.writeBuf(1, 13, pad(pNum(s->hass_state) + "W", 4));
            lcd.writeBuf(1, 19, std::to_string(s->sys.t_sensor) + lcd.cc(0)); // t_sensor temp
            lcd.writeBuf(1, 32 - gpu_temps.size(), pad(pBytes(s->gpu.vram_used), 6));
            lcd.writeBuf(1, 39 - gpu_temps.size(), gpu_temps + lcd.cc(0));

            lcd.writeBuf(2, 0, pad(std::to_string((int)s->cpu.ptotal) + "W", 8, JUST::LEFT));
            lcd.writeBuf(2, s->cpu.ptotal < 100 ? 4 : 5, std::to_string(cpu_fan) + "R"); // avg fan speed
            lcd.writeBuf(2, 12, lcd.cc(3) + pBytes(s->net.upload));
            lcd.writeBuf(2, 19, lcd.cc(4) + pBytes(s->net.download));
            lcd.writeBuf(2, 26, pad(std::to_string(s->gpu.fan_speed) + "R", 5));
            lcd.writeBuf(2, 31, pad(std::to_string(s->gpu.power_avg) + "/" + std::to_string(s->gpu.power_cap) + "W", 9));

            lcd.writeBuf(3, 0, pad(pNum(s->cpu.vcore, 2) + "V", 7, JUST::LEFT));
            lcd.writeBuf(3, 6, std::to_string(s->cpu.avg_freq) + "MHz");
            lcd.writeBuf(3, 14, lcd.cc(2) + pad(pBytes(s->home.usage.free), 5));
            lcd.writeBuf(3, 21, pad(std::to_string(s->gpu.clock_core) + "/" + std::to_string(s->gpu.clock_mem) + "MHz ", 13));
            lcd.writeBuf(3, 34, pad(pNum(s->gpu.vcore, 3) + "V", 5));
        }

        lcd.flushBuf();
        lcd.clearBuf();
    }

    // goodbye msg
    lcd.writeBuf(2, 0, center("linuxSmartie closed", 40));
    lcd.flushBuf();
}

int main() {
    log(LOG::START, "LINUXSMARTIE", "============================= PROGRAM START ============================="); // to make logs clearer
    std::signal(SIGINT, sighandler);
    std::signal(SIGTERM, sighandler);

    Sensors* pSensors = new Sensors;
    log(LOG::DBG, "main", "main thread pid is {}, size of sensor struct is {} bytes", gettid(),sizeof(Sensors));

    std::function<void(std::stop_token st, Sensors * s)> funcs[] = {displayThread, hassThread, sensorsThread};  // array of functions

    /* what the fucking kind of code is this
        this code below spins up display/sensors/homeassistant functions as threads and halts until sem::main is released in sighandler
        then the program leaves the scope, but before that, it destroys the std::jthreads in the "threads" vector
        this causes all threads to gracefully close and join back into main thread, so we can safely destroy pSensors without segfault */

    {
        std::vector<std::jthread> threads;
        for (auto& f : funcs)
            threads.emplace_back(f, pSensors);  // params: function, stop_token (implied), pointer to sensor struct

        sem::main.acquire();
    }

    delete pSensors;
    return 0;
}