#include <stdio.h>
#include <string.h>
#include <unistd.h> // usleep()

#include <pty.h>
#include <termios.h>
#include <fcntl.h>

#include <sys/select.h>
#include <sys/wait.h>

#include <signal.h>     // handle Ctrl-C/SIGINT

#include <time.h>       // usleep(), nanonsleep() ? 
#include <strings.h>    // strcasecmp

#include <stdlib.h>     // random()
#include <ctype.h>

#define TARGET "./mySTIC"
#define BSIZE 1024
#define LOGGING

#ifdef LOGGING
FILE * fp;
#endif

const char * it_is_now(void) {
    static char buffer[100];
    time_t timer;
    struct tm* tm_info;

    timer = time(NULL);
    tm_info = localtime(&timer);
    strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", tm_info);
    return buffer;
}

void slow_write(int fd, int speed, char * buffer, int len) {
    int x;
    for( x = 0; x < len; x++) {
        usleep(speed);
        write( fd, &buffer[x], 1);
    }
}

struct render {
    int speed;
    int effect;
} current_render;

int render_overlimit = 0;

void reset_render(void) {
    current_render.speed = 0;
    current_render.effect = 0;
    render_overlimit = 0;
}


#define TRIGGER "^"
#define SLEEP_LIMIT 30

int ms_sleep(unsigned int ms) {
    int result = 0;
    struct timespec ts = {
        ms / 1000, 
        (ms % 1000) * 1000000L
    };

    do {
        struct timespec ts_sleep = ts;
        result = nanosleep(&ts_sleep, &ts);
    } while ( (-1 == result));
    return result;
}

void render_sleep(void) {
    if (render_overlimit)
        return;

    if (current_render.speed) {
        ms_sleep(current_render.speed * 100);
    }
}

const char * process_trigger(int fd, const char * cp) {
    char ch;
    int i, x, y;
    ch = toupper(*cp);
    cp++;

    switch(ch) {
        case 'D':
            i = 0;
            if (isdigit(*cp)) {
                i = (*cp) - '0';
                cp++;
            };
            if (isdigit(*cp)) {
                i *= 10;
                i += (*cp) - '0';
                cp++;
            };

            if ((i > 0) && (i < 80)) {
#ifdef LOGGING
                fprintf(fp, "DEL %02d\n", i);
#endif                
                for (x = 0; x < i; x++ ) {
                    write(fd, "\b \b", 3);
                }
            };
            break;

        case 'C':
            i = 0;
            if (isdigit(*cp)) {
                i = (*cp) - '0';
                cp++;
            };
            if (isdigit(*cp)) {
                i *= 10;
                i += (*cp) - '0';
                cp++;
            };
            break;

        case 'G':
            x = 0;
            if (isdigit(*cp)) {
                x = (*cp) - '0';
                cp++;
            };
            if (isdigit(*cp)) {
                x *= 10;
                x += (*cp) - '0';
                cp++;
            };
            y = 0;
            if (isdigit(*cp)) {
                y = (*cp) - '0';
                cp++;
            };
            if (isdigit(*cp)) {
                y *= 10;
                y += (*cp) - '0';
                cp++;
            };
            break;

        case 'R':
            i = 0;
            if (isdigit(*cp)) {
                i = (*cp) - '0';
                cp++;
            };
            if ( ( i > 0 ) && ( i < 10) ) {
#ifdef LOGGING
                fprintf(fp, "RENDER %d\n", i);
#endif                

                current_render.effect = i;
            } else {
                current_render.effect = 0;
            }
            break;
        case 'S':
            i = 0;
            if (isdigit(*cp)) {
                i = (*cp) - '0';
                cp++;
            };
            if ( ( i > 0 ) && ( i < 10) ) {
#ifdef LOGGING
                fprintf(fp, "SPEED %d\n", i);
#endif                

                current_render.speed = i;
            } else {
                current_render.speed = 0;
            }
            break;
        case 'P':
            i = 0;
            if (isdigit(*cp)) {
                i = (*cp) - '0';
                cp++;
            };
            if ( ( i > 0 ) && ( i < 10) ) {
#ifdef LOGGING
                fprintf(fp, "PAWS %d\n", i);
#endif                
                // sleep(i);

                if (!render_overlimit) {
                    sleep(i);
                };
            }
            break;
        
    }
    return cp;
}

void render_effect(int fd, char ch) {
    int effect = current_render.effect;
    
    render_sleep();
    int x = write(fd, &ch, 1);

    return;

    switch (effect) {
        case 0: 
        default:
            write(fd, &ch, 1); 
            break;
    }
}

void render( int fd, const char * string_out ) {
    const char * cp = string_out;
    const char * trigger = cp;
    time_t start = time(NULL);
    int elapsed;
    int over = 0;

    reset_render();

#ifdef LOGGING
    fprintf(fp, "render(%d, %s)\n", fd, string_out);
    fflush(fp);
#endif

    // Check our time from time to time.
    // If we start running long, kill sleeps.

    while ( (trigger = strstr(cp, TRIGGER)) != NULL) {
        // There is special things to handle in here.
        while ( cp != trigger ) {
            elapsed = time(NULL)-start;
            if (elapsed > SLEEP_LIMIT) {
                render_overlimit = 1;
                current_render.speed = 0;
            };

#ifdef LOGGING
            fprintf(fp, "re(%c)\n", *cp);
            fflush(fp);
#endif
            // write(fd, cp, 1 );
            render_effect(fd, *cp);
            cp++;
        };

#ifdef LOGGING
        fprintf(fp, "at trigger: (%s)\n", cp);
        fflush(fp);
#endif

        cp += strlen(TRIGGER);

        // Ok, we're pointing at the trigger -- do something.
        cp = process_trigger(fd, cp);

#ifdef LOGGING
        fprintf(fp, "after trigger: (%s)\n", cp);
        fflush(fp);
#endif

    };

    // We still might be under a rendering effect.
    while (*cp != 0) {
        // write(fd, cp, 1);
        render_effect(fd, *cp);
        cp++;
    }
}

void harry_event(int fd) {
    // Make something happen
    char buffer[100];
    int r = random() % 5;

    const char * phrases[] = 
    {
        "Hahaha",
        "Snicker, snicker",
        "Boo!",
        "MeOW",
        "I see U"
    };
    const char * cp;

#ifdef LOGGING
    fprintf(fp, "harry_event(%d)\n", fd);
    fflush(fp);
#endif

    cp = phrases[r];

    sprintf(buffer, "^S2%s^P2^D%02d", cp, (int)strlen(cp));
    // write(fd, )  is working just fine here!
    // write(fd, buffer, strlen(buffer));

#ifdef LOGGING
    fprintf(fp, "harry_event: render(%d, \"%s\")\n", fd, buffer);
    fflush(fp);
#endif

    render(fd, buffer);
}

/* 
NOTE: Logging is single file, don't use in production!
It won't handle multiple writers.
*/
char * username = NULL;
char * fullname = NULL;

void pcopy(char * pstring, char * str) {
    int len = (int)*pstring;
    strncpy( str, pstring+1, len );
    str[len] = 0;
}

int locate_user(const char *alias) {
    FILE * user;
    char buffer[0x600];
    char temp[100];

    user = fopen("data/users.dat", "rb");
    if (user == NULL)
        return 0;

    // Carry on!
    while (fread(buffer, 0x600, 1, user) == 1) {
        pcopy( buffer + 0x6d, temp );
        if ( strcasecmp( temp, username) == 0) {
            pcopy(buffer + 0x8c, temp );
            fullname = strdup(temp);
            break;
        }
        /*
        printf("Alias: %s\n", temp);
        pcopy(buffer + 0x8c, temp );
        printf("Full Name: %s\n", temp );
        */
    }
    fclose(user);
    return 1;
}

// Buffers are BSIZE + 1, so a buffer that size can strcpy safely.

void mangle( char * buffer ) {
    // Ok, we want to look for words to:
    // MaNGlE , or transpose (both?!)
    // or possibly transpose words

}

int main(int argc, char * argv[])
{
    int master;
    pid_t pid;
    
#ifdef LOGGING    
    // FILE * fp;

    fp = fopen("mystic_pipe.data", "wb");
    if ( fp == NULL ) {
        return 2;
    }
#endif

    srandom(time(NULL));

    // ./mystic -TID7 -IP192.168.0.1 -HOSTUnknown -ML1 -SL0 -ST2 -CUnknown -Ubugz -PUWISHPASSWORD
    // ./mystic -TID7 -IP192.168.0.1 -HOSTUnknown -ML0 -SL0 -ST0 -CUnknown

    // ./mystic -TID7 -IP192.168.0.1 -HOSTUnknown -ML1 -SL0 -ST2 -CUnknown -Ubugz -PUP2LAT3
    // ./mystic -TID7 -IP192.168.0.1 -HOSTUnknown -ML0 -SL0 -ST0 -CUnknown

    // ./mystic -TID7 -IP192.168.0.1 -HOSTUnknown -ML0 -SL0 -ST0 -CUnknown
    // ./mystic -TID9 -IP192.168.0.1 -HOSTUnknown -ML0 -SL1 -ST0 -CUnknown

    // ./mystic -TID7 -IP192.168.0.1 -HOSTUnknown -ML1 -SL0 -ST2 -CUnknown -Ubugz -PUP2LAT3
    // ./mystic -TID9 -IP192.168.0.1 -HOSTUnknown -ML1 -SL1 -ST2 -CUnknown -Ubugz -PUP2LAT3

    // SSH:  -ML1 -ST2
    // Telnet: -ML0 -ST0


    // 

    // -U<username>
    for (int x = 0; x < argc; x++) {
        if (strncmp("-U", argv[x], 2) == 0) {
            username = argv[x] + 2;
#ifdef LOGGING
            fprintf(fp, "Username: [%s]\n", username);
#endif            
            break;
        }
    }

    if (username != NULL) {
        locate_user(username);
#ifdef LOGGING
        fprintf(fp, "Username: [%s] A.K.A. [%s]\n", username, fullname);
#endif        
    }

    // With IGNBRK  I don't think I need this anymore.
    // signal(SIGINT, SIG_IGN);

    pid = forkpty(&master, NULL, NULL, NULL);

    // impossible to fork
    if (pid < 0) {
        return 1;
    }

    // child
    else if (pid == 0) {
        char *args[20];     // max 20 args
        int x;
        args[0] = TARGET;

        for ( x = 1; x < argc; x++ ) {
            args[x] = argv[x];
        };
        args[x] = NULL;
        // char *args[] = { "vim", "test.txt", NULL }; // argv; //{ NULL };

        // run Mystic, run!
        execvp( TARGET, args);
    }

    // parent
    else {
        // remove the echo
        // ICANON - raw mode.  No more line buffering!
        struct termios tios, orig1;
        struct timeval timeout;
        int last_event;

        tcgetattr(master, &tios);
        tios.c_lflag &= ~(ECHO | ECHONL | ICANON );
        tcsetattr(master, TCSAFLUSH, &tios);

        tcgetattr(1, &orig1);
        tios = orig1; 
        tios.c_iflag &= ~(ICRNL | IXON);  // Disable software flow control

        tios.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN ); 

        // https://viewsourcecode.org/snaptoken/kilo/02.enteringRawMode.html
        // ISIG should be Ctrl-C and Ctrl-Z IGNBRK + 
        tcsetattr(1, TCSAFLUSH, &tios);


        for (;;) {

            // define estruturas para o select, que serve para verificar qual
            // se tornou "pronto pra uso"
            fd_set          read_fd;
            fd_set          write_fd;
            fd_set          except_fd;

            // inicializa as estruturas
            FD_ZERO(&read_fd);
            FD_ZERO(&write_fd);
            FD_ZERO(&except_fd);

            // atribui o descritor master, obtido pelo forkpty, ao read_fd
            FD_SET(master, &read_fd);
            // atribui o stdin ao read_fd
            FD_SET(STDIN_FILENO, &read_fd);

            // o descritor tem que ser unico para o programa, a documentacao
            // recomenda um calculo entre os descritores sendo usados + 1

            // we're in luck!  The last parameter is time interval/timeout.  :D
            timeout.tv_sec = 10;
            timeout.tv_usec = 0;

            // select(master+1, &read_fd, &write_fd, &except_fd, NULL);
            if ( select(master+1, &read_fd, &write_fd, &except_fd, &timeout) == 0 ) {
                // This means timeout!
                harry_event(STDOUT_FILENO);
#ifdef LOGGING
                fprintf(fp, "%s : TICK\n", it_is_now());
                fprintf(fp, "STDOUT is %d\n", STDOUT_FILENO);
#endif                
            }

            char input[BSIZE + 1];
            char output[BSIZE + 1];
            int total;

            // read_fd esta atribuido com read_fd?
            if (FD_ISSET(master, &read_fd))
            {
                // leia o que bc esta mandando
                if ((total = read(master, &output, BSIZE)) != -1) {
                    // e escreva isso na saida padrao
                    output[total] = 0;

                    if (random() % 20 < 3) {
                        mangle( output );
                    }

                    write(STDOUT_FILENO, &output, total);

                    // This is OUTPUT from the BBS
#ifdef LOGGING
                    fprintf(fp, ">> [%s]\n", output);
#endif
                } else
                    break;
            }

            // read_fd esta atribuido com a entrada padrao?
            if (FD_ISSET(STDIN_FILENO, &read_fd))
            {
                // leia a entrada padrao
                total = read(STDIN_FILENO, &input, BSIZE);
                input[total] = 0;
                // e escreva no bc
                write(master, &input, total);

                // This is INPUT from the USER
#ifdef LOGGING
                fprintf(fp, "<< [%s]\n", input);
#endif
             }
        }

        tcsetattr(1, TCSAFLUSH, &orig1);
#ifdef LOGGING
        fclose(fp);
#endif        
    }
    return 0;
}