// main.cpp — Info display for SSD1306 128x64 using gfx::LinuxFBDisplay.
//
// Build:  see CMakeLists.txt
// Run:    ./gfx_info_display              # defaults to /dev/fb1
//         ./gfx_info_display /dev/fb0     # override

#include "gfx_canvas.h"
#include "gfx_font_5x7.h"
#include "linux_fb_display.h"

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <string>

#include <ifaddrs.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <unistd.h>

// ---------------------------------------------------------------------------
// Configuration
// ---------------------------------------------------------------------------
constexpr int16_t SCREEN_W = 128;
constexpr int16_t SCREEN_H = 64;    // 16 yellow on top and 48 blue on bottom

constexpr const char* ETH_IFACE  = "eth0";
constexpr const char* WLAN_IFACE = "wlan0";

// ---------------------------------------------------------------------------
// Network helper
// ---------------------------------------------------------------------------
static std::string get_ip(const char* iface_name) {
    struct ifaddrs* ifaddr = nullptr;
    if (getifaddrs(&ifaddr) == -1) return "err";

    std::string result = "down";
    for (auto* ifa = ifaddr; ifa; ifa = ifa->ifa_next) {
        if (!ifa->ifa_addr) continue;
        if (ifa->ifa_addr->sa_family != AF_INET) continue;
        if (std::strcmp(ifa->ifa_name, iface_name) != 0) continue;

        char buf[INET_ADDRSTRLEN];
        auto* sa = reinterpret_cast<sockaddr_in*>(ifa->ifa_addr);
        inet_ntop(AF_INET, &sa->sin_addr, buf, sizeof(buf));
        result = buf;
        break;
    }

    freeifaddrs(ifaddr);
    return result;
}

// ---------------------------------------------------------------------------
// Text centering helper
// ---------------------------------------------------------------------------
static void draw_centered(gfx::GfxCanvas& disp, int16_t y, const char* text) {
    int16_t bx, by;
    uint16_t bw, bh;
    disp.getTextBounds(text, 0, 0, bx, by, bw, bh);
    disp.drawString((SCREEN_W - static_cast<int16_t>(bw)) / 2, y, text,
                    gfx::colors::white);
}

// ---------------------------------------------------------------------------
// Signal handling
// ---------------------------------------------------------------------------
static volatile sig_atomic_t g_running = 1;

static void signal_handler(int) { g_running = 0; }

// ---------------------------------------------------------------------------
// Main
// ---------------------------------------------------------------------------
int main(int argc, char* argv[]) {
    const char* fb_device = "/dev/fb1";
    if (argc > 1) fb_device = argv[1];

    gfx::LinuxFBDisplay display(SCREEN_W, SCREEN_H);
    if (!display.open(fb_device)) return EXIT_FAILURE;

    display.setFont(gfx::font_5x7);
    display.setTextColor(gfx::colors::white);
    display.setTextWrap(false);

    signal(SIGINT,  signal_handler);
    signal(SIGTERM, signal_handler);

    char line_buf[64];

    while (g_running) {
        display.fillScreen(gfx::colors::black);

        // --- Network info ---
        std::string eth_ip  = get_ip(ETH_IFACE);
        std::string wlan_ip = get_ip(WLAN_IFACE);

        std::snprintf(line_buf, sizeof(line_buf), "ETH:  %s", eth_ip.c_str());
        display.setCursor(0, 0);
        display.print(line_buf);

        std::snprintf(line_buf, sizeof(line_buf), "WLAN: %s", wlan_ip.c_str());
        display.setCursor(0, 8);
        display.print(line_buf);

        // --- Separator ---
        display.drawHLine(0, 17, SCREEN_W, gfx::colors::white);

        // --- Date and time ---
        std::time_t now = std::time(nullptr);
        std::tm* tm = std::localtime(&now);

        std::snprintf(line_buf, sizeof(line_buf), "%04d-%02d-%02d",
                      tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday);
        draw_centered(display, 29, line_buf);

        std::snprintf(line_buf, sizeof(line_buf), "%02d:%02d:%02d",
                      tm->tm_hour, tm->tm_min, tm->tm_sec);
        draw_centered(display, 41, line_buf);

        display.update();

        // --- Sleep aligned to next whole second ---
        struct timespec ts{};
        clock_gettime(CLOCK_REALTIME, &ts);
        ts.tv_sec += 1;
        ts.tv_nsec = 0;
        clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, &ts, nullptr);
    }

    display.fillScreen(gfx::colors::black);
    std::printf("Exiting.\n");
    return EXIT_SUCCESS;
}