/** file cwrap.c - line wrapping demo with color escapes
    escape codes: "###..." sequences of (n) hash display as (n-1) hashes
                  "#n" forced linebreak

                  "#=" reset ansi color
                  "#g" ansi brightly black (gray)
                  "#R" ansi bold red
                  "#G" ansi bold green
                  etc...

                  unrecognized char prints a single hash also,
                  hash at end of line won't crash or infinite-loop
                  (anymore, thank goodness!)

    todo: multiple columns like a newspaper or magazine,
          each wrapped individually.
**/

#include <stdio.h>
#include <stdlib.h>

int COLUMNS = 75; /* terminal character columns, not paragraphs */

#define DO_FILES

#define pass(x) do { printf("%s\n", #x); } while(0)
#define LEVEL 100
#define if_debug(x) if((x) && (x) < LEVEL)

#define dummy (-1)

#define RESET   "\x1b[0m"
#define GRAY    "\x1b[1;30m"
#define RED     "\x1b[1;31m"
#define GREEN   "\x1b[1;32m"
#define YELLOW  "\x1b[1;33m"
#define BLUE    "\x1b[1;34m"
#define MAGENTA "\x1b[1;35m"
#define CYAN    "\x1b[1;36m"
#define WHITE   "\x1b[1;37m"

typedef enum {
    reset=0, gray, red, green, yellow, blue, magenta, cyan, white,
    ansimax=white
} ansi_t;

const char *ANSI[] = {
    RESET, GRAY, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE
};

//-----------------------------------------------------------------------

int runlen(char *msg, int width, int *run) {
    int i, bump, stop;
    int pos, notrun;
    char prev, c;

    if(!run) run = &notrun;
    pos = *run = 0;

    prev = c = '?';
    bump = stop = 0;

    /* !! looping until the PREVIOUS char in string prevents "...#" bug !! */
    /* delayed char kinda sucks reading from a terminal but this is string */

    for(i = 0; prev != '\0'; i++) {
        prev = c; c = msg[i];

        if(c == '#' && prev != c)    continue;

        if(prev != '#' || prev == c) pos++;

        if(!c) bump = i;
        if(c == ' ' && prev != c) bump = i;

        /* forced linebreak, i+1 to include the 'n' too, our "previous" */
        /* trick wouldn't work without an extra char of context.        */

        if(c == 'n' && prev == '#') bump = i+1;

#ifdef DO_FILES
        if(c == '\n') bump = i+1;
#endif

        /* OR EQUAL!, seldom seen fencepost error otherwise */
 
        if(pos <= width) { stop = bump; *run = pos; }
        else break;

        /* this hasn't proved neccessary but should've been disasterous... */
        prev = c;
    }
    return stop;
}

//-------------------------------------------------------------------------
int printchar(char *msg, int i) {
    char prev, c, *t;

    c = msg[i];
    if(0 < i) prev = msg[i-1];
    else prev = ' ';

    if(!c) return 0;

#ifdef DO_FILES
    if(c == '\n') return 1;
#endif

    if(c == '#' && prev != c) return 0;

    if(prev != '#') putc(c, stdout);
    else switch(c) {

        case 'n': return 1; break;

        case '=': printf( ANSI[reset] );   break;
        case 'g': printf( ANSI[gray] );    break;
        case 'R': printf( ANSI[red] );     break;
        case 'G': printf( ANSI[green] );   break;
        case 'Y': printf( ANSI[yellow] );  break;
        case 'B': printf( ANSI[blue] );    break;
        case 'M': printf( ANSI[magenta] ); break;
        case 'C': printf( ANSI[cyan] );    break;
        case 'W': printf( ANSI[white] );   break;

        default: putc('#', stdout); break;
    };
    return 0;
}
//-------------------------------------------------------------------------

int wrap(char *msg, int width, int pos) {
    int i, w, len, run, lb;

    if(!msg || !*msg) { printf("\r\n"); return 0; }

    while(*msg) {

        w = width-pos;
        len = runlen(msg, w, &run);

        for(i = 0; i < len; i++) lb = printchar(msg, i);

        if(lb) { printf("\r\n"); pos = 0; }
        else pos += run;

        msg += len;
        if(*msg) {
            while(*msg == ' ') msg++;

            /* this is wrapping linebreak only */
            if(!lb) printf("\r\n");
            pos = 0;
        }
    }
    return pos;
}

//------------------------------------------------------------------------

int main(int argc, char *argv[]) {
    int i, len, pos;
    char *line, buffer[4096];
    char *lyrics[] = {
        "",
        "Bye bye Miss #RAmer#Wican#B Pie#=, drove my Chevy to the levy 'cause the levy was dry.",
        " And good ol' boys were drinking wisky and rye, singing: 'This will be the day that I die'...#n",
        "",
        "Did you write the Book of Love, and do you have faith in #YGod#= above, if the Bible tells you so.",
        " Do you believe in #Crock 'n roll#=, can music save, #gyour mortal soul#=, and can you teach me to dance real slow...#n",
        "",
        "Well I know that you're in love with him, 'cause I saw you dancing, in the gym.",
        " You both kicked off your shoes, man I love those rythmly #Bblues!#=",
        " Ooh! I was a lonely teenage broncho buck, with a #Mpink carnation#= and a pickup truck,",
        " But I knew I was out of luck, the day, the music, died.#n",
        "",
        "I was singing: Bye bye Miss American Pie...#n",
        "#.#n#",
        "#.#n#asdf",
        "abc#nxyz",
        NULL
    };

    argc--;
    if(argc) { sscanf(argv[1], "%d", &COLUMNS); argv++; argc--; }
    if(12 > COLUMNS || COLUMNS > 120) COLUMNS = 75;

    for(i = 0, pos = 0; lyrics[i] != NULL; i++) {
        line = lyrics[i];
        pos = wrap(line, COLUMNS, pos);
    }

#ifdef DO_FILES
    while(argc) {
        freopen(argv[1], "r", stdin);

        pos = 0;
        while( fgets(buffer, sizeof(buffer), stdin) ) {
            pos = wrap(buffer, COLUMNS, pos);
        }
        argv++; argc--;
    }
#endif

    return 0;
}