#include <array>
#include <chrono>
#include <csignal>
#include <cstdint>
#include <functional>
#include <mutex>
#include <print>
#include <semaphore>
#include <stop_token>
#include <string>
#include <thread>
#include <vector>
//
#include <LCDDisplay.hpp>
#include <cpu.hpp>
#include <gpu.hpp>
#include <hass.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

struct Sensors {
    std::array<std::string, 2> td;
    std::string loadavg;
    mem_usage_t ram;
    mem_usage_t home;
    cpu::sensors cpu;
    gpu::sensors gpu;
    float hass_state = 0.0f;
    std::mutex mtx;  // making sure the struct isnt accessed by multiple threads at once
};

void sighandler(int s) {
    std::println("[Signal] got SIGINT/SIGTERM, exiting...");
    sem::main.release();
    sem::display.release();
}

void hassThread(std::stop_token st, Sensors* s) {
    // std::println("[Thread] Starting hass_thread, pid {}", gettid());
    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
            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) {
    // std::println("[Thread] Starting sensors_thread, pid {}, poll interval {} ms", gettid(), LCD_INTERVAL_MS);
    cpu::detectHwmon(&s->cpu, "0000:00:18.3");
    gpu::detectHwmon(&s->gpu, "0000:08:00.0");

    while (!st.stop_requested()) {
        auto start = std::chrono::steady_clock::now();
        {
            std::lock_guard<std::mutex> lock(s->mtx);  // will unlock when it goes out of scope, this is why this whole thing is in braces
            s->td = getTimeDate();
            s->loadavg = getAvgs();
            s->ram = getRam();
            s->home = getDisk("/home/drath");
            cpu::update(&s->cpu);
            gpu::update(&s->gpu);
        }

        // std::println("[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) {
    // std::println("[Thread] Starting display_thread, pid {}", gettid());
    LCDDisplay lcd(LCD_PORT);

    lcd.setContrast(LCD_CONTRAST);
    lcd.setBacklight(true);
    lcd.setCustomChar(0, {16, 6, 9, 8, 8, 9, 6, 0});  // celcius

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

            auto gpu_temps = (s->gpu.hotspot_temp) ? "/" + std::to_string(s->gpu.hotspot_temp) : "";
            gpu_temps += (s->gpu.mem_temp) ? "/" + std::to_string(s->gpu.mem_temp) : "";

            lcd.writeBuf(0, 0, pad(s->td[1], 11, true) + "   " + s->td[0] + lcd.bar(1, s->gpu.core_usage / 100.0) + pad(s->loadavg, 17));

            lcd.writeBuf(1, 0, pad(std::to_string(s->cpu.tctl) + "/" + std::to_string(s->cpu.tccd1) + lcd.cc[0], 8, true));
            lcd.writeBuf(1, 8, pad(pBytes(s->ram.used, true) + "B", 7, true));
            lcd.writeBuf(1, 16, pad(pNum(s->hass_state) + "W", 4));
            lcd.writeBuf(1, 22, pad(pBytes(s->gpu.vram_used) + "B", 7));
            lcd.writeBuf(1, 29, pad(std::to_string(s->gpu.edge_temp) + gpu_temps + lcd.cc[0], 11));

            lcd.writeBuf(2, 0, pad(pNum(s->cpu.ptotal, 1) + "W", 8, true));
            lcd.writeBuf(2, 8, "home:" + pad(pBytes(s->home.free), 5));

            lcd.writeBuf(2, 20, pad(std::to_string(s->gpu.fan_pwm) + "%", 4));
            lcd.writeBuf(2, 25, pad(std::to_string(s->gpu.fan_speed), 4) + "R");
            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, 3) + "V", 7, true));
            lcd.writeBuf(3, 7, std::to_string(s->cpu.avg_freq) + "MHz");
            lcd.writeBuf(3, 21, pad(std::to_string(s->gpu.core_clock) + "/" + std::to_string(s->gpu.mem_clock) + "MHz ", 13));
            lcd.writeBuf(3, 34, pad(pNum(s->gpu.vcore, 3) + "V", 5));
        }

        lcd.flushBuf();
    }

    lcd.clearBuf();
    lcd.writeBuf(1, 10, "linuxSmartie closed");
    lcd.flushBuf();
}

int main(int argc, char* argv[]) {
    std::signal(SIGINT, sighandler);
    std::signal(SIGTERM, sighandler);
    // std::println("[Thread] Main thread, pid {}", gettid());

    Sensors* pSensors = new Sensors;
    // std::println("sensors addr: {}\nsensors.gpu addr", (void*)pSensors, pSensors->gpu);

    std::vector<std::function<void(std::stop_token st, Sensors * s)>> funcs = {displayThread, hassThread, sensorsThread};

    /* wtf is this?
        this spins up funcs as threads and halts until sMain semaphore is released in sighandler
        its scoped because when sMain is released, program waits until all the threads join back before leaving the scope
        threads object has to be inside the scope too because destruction of std::jthread is what actually makes threads join.
    */

    {
        std::vector<std::jthread> threads;
        for (auto& f : funcs)
            threads.emplace_back(f, pSensors);

        sem::main.acquire();
    }

    delete pSensors;
    std::println("Main thread exiting");
    return 0;
}