/* abandon all hope, this shit is a mess */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <ncurses.h>
#include <rtl-sdr.h>
#include <curl/curl.h>

/* define ANSI escape chars and math */
#define RESET "\033[0m"
#define BOLD "\033[1m"
#define UNDERLINE "\033[4m"
#define BLINK "\033[5m"
#define REVERSED "\033[7m"
#define BLACK "\033[30m"
#define RED "\033[31m"
#define GREEN "\033[32m"
#define YELLOW "\033[33m"
#define BLUE "\033[34m"
#define MAGENTA "\033[35m"
#define CYAN "\033[36m"
#define WHITE "\033[37m"
#define BG_BLACK "\033[40m"
#define BG_RED "\033[41m"
#define BG_GREEN "\033[42m"
#define BG_YELLOW "\033[43m"
#define BG_BLUE "\033[44m"
#define BG_MAGENTA "\033[45m"
#define BG_CYAN "\033[46m"
#define BG_WHITE "\033[47m"

#define M_PI 3.14159265358979323846

/*define DEFCON level stuff */
#define DEFCON_URL "https://defconwarningsystem.com/code.dat"
unsigned int level;
unsigned int cooldown = 1800;
unsigned int cooldown_timer = 0;
bool cooldown_reset = false;

size_t write_data(void *ptr1, size_t size, size_t nmemb, FILE *stream) {
    size_t written = fwrite(ptr1, size, nmemb, stream);
    return written;
};

/* declare global variables */

rtlsdr_dev_t *dev = NULL;
uint32_t device_index = 0;
uint32_t MHz = 1000000;
uint32_t kHz = 1000;
uint32_t bandwidth;
uint32_t center_freq;
bool SDR_PRESENT = false;
bool RSS_LIST_PRESENT = false;
bool COMMS_AVAILABLE = false;
bool CURL_AVAILABLE = false;
int term_rows, term_cols;

/* declare ncurses windows */

WINDOW * sdr;
WINDOW * rss;
WINDOW * defcon;

/* startup screen! :3 */

void startup_screen() {
    printf("\n\n");
    printf(CYAN"                             █████     ███                      ████ \n");
    printf("                             ░░███     ░░░                      ░░███ \n");
    printf("  █████   ██████  ████████   ███████   ████  ████████    ██████  ░███ \n");
    printf(" ███░░   ███░░███░░███░░███ ░░░███░   ░░███ ░░███░░███  ███░░███ ░███ \n");
    printf("░░█████ ░███████  ░███ ░███   ░███     ░███  ░███ ░███ ░███████  ░███ \n");
    printf(" ░░░░███░███░░░   ░███ ░███   ░███ ███ ░███  ░███ ░███ ░███░░░   ░███ \n");
    printf(" ██████ ░░██████  ████ █████  ░░█████  █████ ████ █████░░██████  █████\n");
    printf("░░░░░░   ░░░░░░  ░░░░ ░░░░░    ░░░░░  ░░░░░ ░░░░ ░░░░░  ░░░░░░  ░░░░░ \n\n");
    printf("        v0.0.1\n" RESET);
}

/* declare reusable functions */

void get_terminal_size(int *rows, int *cols) {
    struct winsize w;
    ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
    *rows = w.ws_row;
    *cols = w.ws_col;
}

/* read out shell command output */
char* readout(const char* command, char* buffer, size_t size) {
    FILE *fp = popen(command, "r");
    if (fp == NULL) {
        perror("popen");
        exit(EXIT_FAILURE);
    }
    if (fgets(buffer, size, fp) == NULL) {
        perror("fgets");
        pclose(fp);
        exit(EXIT_FAILURE);
    }
    pclose(fp);
    /* remove the newline character at the end of the buffer */
    buffer[strcspn(buffer, "\n")] = 0;
    return buffer;
}

/* declare functions for startup checks */
void util_check() {
    printf("curl: ");
    if (system("curl --version > /dev/null 2>&1") == 0) {
        printf(GREEN"OK\n"RESET);
        CURL_AVAILABLE = true;
    } else {
        printf(RED"FAIL\n"RESET);
    }
    printf("rtl-sdr: ");
    if (system("ls /usr/bin/rtl_sdr > /dev/null 2>&1") == 0) {
        printf(GREEN"OK\n"RESET);
        SDR_PRESENT = true;
    } else {
        printf(RED"FAIL\n"RESET);
    }
}

void rtl_sdr_check() {
    
    if (rtlsdr_open != NULL && SDR_PRESENT == true) {
        int index;
        const char* device_name;
        char serial[256], product[256], manufact[256];
        device_name = rtlsdr_get_device_name(device_index);
        rtlsdr_get_device_usb_strings(index, manufact, product, serial);
        printf("device name: " GREEN);
        printf(device_name);
        printf("\n" RESET);
        printf(YELLOW"serial: %s\n", serial);
        printf("product: %s\n", product);
        printf("manufacturer: %s\n", manufact);
        printf(RESET);
        rtlsdr_close;
    } else {
        printf(RED"SDR not detected! skipping...\n"RESET);
    }
}

void defcon_level_check() {
    FILE *fp = fopen(".last_known_defcon", "r");
    if ( fp == NULL) {
        printf(YELLOW"DEFCON level cache file not found or corrupted, creating new...\n"RESET);
        FILE *fp = fopen(".last_known_defcon", "w");
        fputc(5, fp);
        fclose(fp);
    } else {
        int last_known_startup = fgetc(fp);
        printf("DEFCON level cache file found! last known level: %d\n", last_known_startup);
        fclose(fp);
    } 
}

void rss_sources_check() {
    if (COMMS_AVAILABLE == true) {
        FILE *fp = fopen(".rss_feed_list", "r");
        if ( fp == NULL) {
            printf(RED"RSS feed source list not found!\n"RESET);
            fclose(fp);
        } else {
            printf(GREEN"RSS feed source list found! sources:\n\n"RESET);
            RSS_LIST_PRESENT = true;
            int line_count = 0;
            char buffer[256];

            while (fgets(buffer, sizeof(buffer), fp) != NULL) {
            line_count++;
            }

            char feed_source[line_count][256];
            fseek(fp, 0, SEEK_SET);
            for (int i = 0; i < line_count; i++) {
                fgets(feed_source[i], sizeof(feed_source[i]), fp);
                printf(GREEN"%s\n"RESET, feed_source[i]);
            }
            fclose(fp);
        } 
    } else {
        printf(RED"internet not available! skipping..."RESET);
    }    
}


/* making sure program has everything it needs to run, more checks will be introduced as capabilities are added */

void startup_checks() {
    printf("######################################################################\n");
    printf(MAGENTA"STARTUP CHECKS\n"RESET);
    printf("----------------------------------------------------------------------\n");
    printf(MAGENTA"SYSTEM STATUS\n\n"RESET);
    printf("date: %s\n", readout("date \"+%D\"", (char[100]){0}, 100));
    printf("time: %s\n", readout("date \"+%T\"", (char[100]){0}, 100));
    /* internet connectivity check */
    int status = system("ping -c 1 fsf.org > /dev/null 2>&1");
    if (status == 0) {
        printf("internet connectivity status: ");
        printf(GREEN"online\n"RESET);
        COMMS_AVAILABLE = true;
    } else {
       printf("internet connectivity status: ");
       printf(RED"offline\n"RESET);
       printf(RED"internet-dependent capabilities will be unavailable!\n"RESET);
       COMMS_AVAILABLE = false;
    }
    /* get terminal size */
    get_terminal_size(&term_rows, &term_cols);
    printf("terminal size:  ");
    printf(YELLOW"%dx%d\n"RESET, term_rows, term_cols);
    printf("----------------------------------------------------------------------\n");
    /* utilities presence check */
    printf(MAGENTA"UTILITIES\n\n"RESET);
    util_check();
    printf("----------------------------------------------------------------------\n");
    printf(MAGENTA"SOFTWARE-DEFINED RADIO\n\n"RESET);
    rtl_sdr_check();
    printf("----------------------------------------------------------------------\n");
    printf(MAGENTA"DEFCON LEVEL STATUS\n\n"RESET);
    defcon_level_check();
    printf("----------------------------------------------------------------------\n");
    printf(MAGENTA"RSS AGGREGATOR CHECK\n\n"RESET);
    rss_sources_check();
    printf("----------------------------------------------------------------------\n");
    printf(MAGENTA"all checks finished!\n"RESET);
    printf("######################################################################\n");
    printf(BLUE"initializing in 5 seconds...\n\n"RESET);
    //usleep(5000000);
    if (SDR_PRESENT == true)
    {
        printf(GREEN"initializing RTL-SDR...\n"RESET);
        rtlsdr_open(&dev, device_index);
    }
    if (RSS_LIST_PRESENT == true && COMMS_AVAILABLE == true && CURL_AVAILABLE == true) {
        printf(GREEN"initializing RSS aggregator...\n"RESET);
    }
    if (COMMS_AVAILABLE == true && CURL_AVAILABLE == true) {
        printf(GREEN"initializing DEFCON level parser...\n"RESET);
    }
    
}


/* define functions for dashboard - WIP */

void init_colors() {
    start_color();
    init_pair(1, COLOR_RED, COLOR_BLACK);
    init_pair(2, COLOR_GREEN, COLOR_BLACK);
    init_pair(3, COLOR_YELLOW, COLOR_BLACK);
    init_pair(4, COLOR_BLUE, COLOR_BLACK);
    init_pair(5, COLOR_MAGENTA, COLOR_BLACK);
    init_pair(6, COLOR_CYAN, COLOR_BLACK);
    init_pair(7, COLOR_WHITE, COLOR_BLACK);
    init_pair(8, COLOR_WHITE, COLOR_RED);
    init_pair(9, COLOR_WHITE, COLOR_GREEN);
}

void print_centered(WINDOW *win, const char *text) {
    int width = getmaxx(win);
    int height = getmaxy(win)/2;
    int length = strlen(text);
    int start_col = (width - length) / 2;
    mvwprintw(win, height, start_col, "%s", text);
}

/* define rtl-sdr specific functions and general SDR workflow - WIP */

/* signal analysis function */
void fourier_transform(unsigned char *buf, double *out, int n) {
    for (int k = 0; k < n; k++) {
        double real = 0.0;
        double imag = 0.0;
        for (int t = 0; t < n; t++) {
            double angle = 2 * M_PI * t * k / n;
            real += buf[t] * cos(angle);
            imag -= buf[t] * sin(angle);
        }
        out[k] = sqrt(real * real + imag * imag);
    }
}

void draw_bar_graph(double *data, int size) {
    wclear(sdr);
    double max_value = 0.0;
    wattron(sdr, COLOR_PAIR(6));
    wprintw(sdr, "center frequency: %.3f MHz    gain: %d    bandwidth: %.3f MHz", center_freq / (double)MHz, rtlsdr_get_tuner_gain(dev), bandwidth / (double)MHz);
    wattroff(sdr, COLOR_PAIR(6));
    double bottom = center_freq - bandwidth / 2.0;
    double step = bandwidth / (double)size;
    for (int i = 0; i < size; i++) {
        if (data[i] > max_value) {
            max_value = data[i];
        }
    }
    wattron(sdr, COLOR_PAIR(4));
    for (int i = 0; i < size; i++) {
        mvwprintw(sdr, i + 1, 0, "%.3f MHz: ", bottom / (double)MHz + i * step / (double)MHz);
        for (int j = 0; j < data[i] * 50 / max_value; j++) {
            wprintw(sdr, ">");
        }
    }
    wattroff(sdr, COLOR_PAIR(4));
    wrefresh(sdr);
}

void rtl_sdr_processing(unsigned char *buf, int buffer_length) {
    int n = buffer_length;
    double *out = (double *)malloc(n * sizeof(double));
    fourier_transform(buf, out, n);
    /* debug
    for (int i = 0; i < n; i++) {
        printf("%f\n", out[i]);
    } */
    draw_bar_graph(out, n);
    free(out);
}

void rtl_sdr_waterfall() {
    bandwidth = 10*MHz;
    rtlsdr_set_tuner_bandwidth(dev, bandwidth);
    uint32_t buffer_length = getmaxy(sdr)-2, n_read = 10; // example buffer length
    unsigned char *buffer = (unsigned char *)malloc(buffer_length);
    rtlsdr_set_center_freq(dev, 104*MHz); //104MHz for testing purposes
    center_freq = rtlsdr_get_center_freq(dev);
    rtlsdr_read_sync(dev, buffer, buffer_length, &n_read);
    rtl_sdr_processing(buffer, buffer_length);
    usleep(500000);
}

/* RSS feed functions & workflow - WIP */



/* DEFCON level functions */

char fetch_defcon_level() {
    CURL *curl;
    CURLcode res;
    FILE *fp;
    unsigned int current_level = 5; //nothing ever happens
    unsigned int last_known;
    cooldown_timer++;

    if(cooldown_timer > cooldown_reset){
        cooldown_reset = true;
    }

    if (cooldown_reset = true) {

        curl = curl_easy_init();
        if (curl) {
            fp = fopen(".last_known_defcon", "w");
            if (fp == NULL) {
                perror("fopen");
                return current_level;
            }

            curl_easy_setopt(curl, CURLOPT_URL, DEFCON_URL);
            curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
            curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);

            res = curl_easy_perform(curl);
            if (res != CURLE_OK) {
                fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
            } else {
                fseek(fp, 0, SEEK_SET);
                int ch = fgetc(fp);
                if (isdigit(ch)){
                    current_level = ch - '0'; // read the DEFCON level from the file
                    last_known = current_level;
                }
            }
            fclose(fp);
            curl_easy_cleanup(curl);
        } else {
            print_centered(defcon, "HTTP request failed :(");
        }

        return current_level;
    }
    else {
        current_level = last_known;
        return current_level;
    }
}

void print_file_lines_ncurses(const char *filename, WINDOW *win) {
    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        perror("fopen");
        return;
    }
    char line[256];
    int y = 1;
    while (fgets(line, sizeof(line), file) != NULL) {
        mvwprintw(win, y++, 1, "%s", line);
        wrefresh(win);
    }
    fclose(file);
}

/* main dashboard function */

void start_dashboard() {
    initscr();
    cbreak();
    noecho();
    init_colors();
    refresh();
    WINDOW * sdr = newwin(term_rows/2-2, term_cols/2, 1, 1);
    WINDOW * rss = newwin(term_rows-2, term_cols/2-2, 1, term_cols/2+2);
    WINDOW * defcon = newwin(term_rows/2, term_cols/2, term_rows/2, 1);
    box(sdr, 0, 0);
    box(rss, 0, 0);
    box(defcon, 0, 0);
    wrefresh(sdr);
    wrefresh(rss);
    wrefresh(defcon);

    while(true) {
        /* SDR window */
        if (SDR_PRESENT == true) {
            rtl_sdr_waterfall();
        }
        else {
            wbkgd(sdr, COLOR_PAIR(8));
            print_centered(sdr, "SDR NOT AVAILABLE");
            wrefresh(sdr);
            usleep(1000000);
        }
        /* RSS window */
        if (COMMS_AVAILABLE == true && CURL_AVAILABLE == true) {
            wbkgd(rss, COLOR_PAIR(9));
            print_centered(rss, "RSS FEED AVAILABLE");
            wrefresh(rss);
            usleep(1000000);
        }
        else {
            wbkgd(rss, COLOR_PAIR(8));
            print_centered(rss, "RSS FEEED NOT AVAILABLE");
            wrefresh(rss);
            usleep(1000000);
        }
        /* DEFCON window */
        if (COMMS_AVAILABLE == true && CURL_AVAILABLE == true) {
            level = fetch_defcon_level();
            switch(level) {
                case 5:
                    wbkgd(defcon, COLOR_PAIR(4));
                    print_file_lines_ncurses("./ascii/level5", defcon);
                    wprintw(defcon, "   DEFCON 5 - NOTHING EVER HAPPENS");
                    break;
                case 4:
                    wbkgd(defcon, COLOR_PAIR(2));
                    print_file_lines_ncurses("./ascii/level4", defcon);
                    wprintw(defcon, "   DEFCON 4 - UNLIKELY TO HAPPEN");
                    break;
                case 3:
                    wbkgd(defcon, COLOR_PAIR(5));
                    print_file_lines_ncurses("./ascii/level3", defcon);
                    wprintw(defcon, "   DEFCON 3 - MAYBE IT WILL HAPPEN");
                    break;
                case 2:
                    wbkgd(defcon, COLOR_PAIR(3));
                    print_file_lines_ncurses("./ascii/level2", defcon);
                    wprintw(defcon, "   DEFCON 2 - SOMETHING WILL HAPPEN");
                    break;
                case 1:
                    wbkgd(defcon, COLOR_PAIR(1));
                    print_file_lines_ncurses("./ascii/level1", defcon);
                    wprintw(defcon, "   DEFCON 1 - IT IS HAPPENING");
                    break;
                default:
                    wbkgd(defcon, COLOR_PAIR(4));
                    print_file_lines_ncurses("./ascii/level5", defcon);
                    wprintw(defcon, "   DEFCON 5 - NOTHING EVER HAPPENS"); //because nothing ever happens
                    break;
            }
            wrefresh(defcon);
            usleep(1000000);
        }
        else {
            wbkgd(defcon, COLOR_PAIR(8));
            print_centered(defcon, "DEFCON CHECK NOT AVAILABLE");
            wrefresh(defcon);
            usleep(1000000);
        }
    
        rtlsdr_close(dev);
        endwin();
    }
}

int main() {
    startup_screen();
    startup_checks();
    start_dashboard();

    return 0;
}