/*
 * view.c -- a silly little viewer program
 *
 * written by Eric S. Raymond <esr@snark.thyrsus.com> December 1994
 * to test the scrolling code in ncurses.
 *
 * modified by Thomas Dickey <dickey@clark.net> July 1995 to demonstrate
 * the use of 'resizeterm()', and May 2000 to illustrate wide-character
 * handling.
 *
 * Takes a filename argument.  It's a simple file-viewer with various
 * scroll-up and scroll-down commands.
 *
 * n    -- scroll one line forward
 * p    -- scroll one line back
 *
 * Either command accepts a numeric prefix interpreted as a repeat count.
 * Thus, typing `5n' should scroll forward 5 lines in the file.
 *
 * The way you can tell this is working OK is that, in the trace file,
 * there should be one scroll operation plus a small number of line
 * updates, as opposed to a whole-page update.  This means the physical
 * scroll operation worked, and the refresh() code only had to do a
 * partial repaint.
 *
 * $Id: view.c,v 1.2 2007/05/28 15:01:58 blymn Exp $
 */

#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <signal.h>
#ifdef NCURSES
#define _XOPEN_SOURCE_EXTENDED
#include <ncurses.h>
#include <term.h>
#else
#include <curses.h>
#endif /* NCURSES */
#include <locale.h>
#include <assert.h>
#include <ctype.h>
#include <termios.h>
#include <util.h>
#include <unistd.h>
#ifdef HAVE_WCHAR
#include <wchar.h>
#endif /* HAVE_WCHAR */
#ifdef DEBUG
#include <syslog.h>
#endif /* DEBUG */

#define UChar(c)    ((unsigned char)(c))
#define SIZEOF(table)   (sizeof(table)/sizeof(table[0]))
#define typeMalloc(type,n) (type *) malloc((n) * sizeof(type))

#define my_pair 1

#undef CURSES_CH_T
#ifdef HAVE_WCHAR
#define CURSES_CH_T cchar_t
#else
#define CURSES_CH_T chtype
#endif /* HAVE_WCHAR */

static void finish(int sig);
static void show_all(const char *tag);

static int shift = 0;
static bool try_color = FALSE;

static char *fname;
static CURSES_CH_T **my_lines;
static CURSES_CH_T **lptr;
static unsigned num_lines;

static void usage(void)
{
    static const char *msg[] = {
            "Usage: view [options] file"
            ,""
            ,"Options:"
            ," -c       use color if terminal supports it"
            ," -i       ignore INT, QUIT, TERM signals"
            ," -n NUM   specify maximum number of lines (default 1000)"
#if defined(KEY_RESIZE)
            ," -r       use old-style sigwinch handler rather than KEY_RESIZE"
#endif
#ifdef TRACE
            ," -t       trace screen updates"
            ," -T NUM   specify trace mask"
#endif
    };
    size_t n;
    for (n = 0; n < SIZEOF(msg); n++)
            fprintf(stderr, "%s\n", msg[n]);
    exit( 1 );
}

static int ch_len(CURSES_CH_T * src)
{
    int result = 0;

#ifdef HAVE_WCHAR
    while (getcchar(src++, NULL, NULL, NULL, NULL) > 0)
            result++;
#else
    while (*src++)
        result++;
#endif
    return result;
}

/*
 * Allocate a string into an array of chtype's.  If UTF-8 mode is
 * active, translate the string accordingly.
 */
static CURSES_CH_T * ch_dup(char *src)
{
    unsigned len = strlen(src);
    CURSES_CH_T *dst = typeMalloc(CURSES_CH_T, len + 1);
    unsigned j, k;
#ifdef HAVE_WCHAR
    wchar_t wstr[CCHARW_MAX + 1];
    wchar_t wch;
    int l = 0;
    mbstate_t state;
    size_t rc;
    int width;
#endif

#ifdef HAVE_WCHAR
    mbrtowc( NULL, NULL, 1, &state );
#endif
    for (j = k = 0; j < len; j++) {
#ifdef HAVE_WCHAR
            rc = mbrtowc(&wch, src + j, len - j, &state);
#ifdef DEBUG
        syslog( LOG_INFO, "[ch_dup]mbrtowc() returns %d", rc );
#endif /* DEBUG */
            if (rc == (size_t) -1 || rc == (size_t) -2)
                break;
            j += rc - 1;
            if ((width = wcwidth(wch)) < 0)
                break;
            if ((width > 0 && l > 0) || l == CCHARW_MAX) {
                wstr[l] = L'\0';
                l = 0;
                if (setcchar(dst + k, wstr, 0, 0, NULL) != OK)
                        break;
                ++k;
            }
            if (width == 0 && l == 0)
                wstr[l++] = L' ';
            wstr[l++] = wch;
#ifdef DEBUG
        syslog( LOG_INFO, "[ch_dup]wch=%x", wch );
#endif /* DEBUG */
#else
            dst[k++] = src[j];
#endif
    }
#ifdef HAVE_WCHAR
    if (l > 0) {
            wstr[l] = L'\0';
            if (setcchar(dst + k, wstr, 0, 0, NULL) == OK)
                ++k;
    }
    setcchar(dst + k, L"", 0, 0, NULL);
#else
    dst[k] = 0;
#endif
    return dst;
}

int main(int argc, char *argv[])
{
    int MAXLINES = 1000;
    FILE *fp;
    char buf[BUFSIZ];
    int i;
    int my_delay = 0;
    CURSES_CH_T **olptr;
    int length = 0;
    int value = 0;
    bool done = FALSE;
    bool got_number = FALSE;
    const char *my_label = "Input";
#ifdef HAVE_WCHAR
    cchar_t icc;
#endif /* HAVE_WCHAR */

    setlocale(LC_ALL, "");

    (void) signal(SIGINT, finish);      /* arrange interrupts to terminate */

    while ((i = getopt(argc, argv, "cin:rtT:")) != EOF) {
            switch (i) {
                case 'c':
                    try_color = TRUE;
                    break;
                case 'i':
                    signal(SIGINT, SIG_IGN);
                    signal(SIGQUIT, SIG_IGN);
                    signal(SIGTERM, SIG_IGN);
                    break;
                case 'n':
                    if ((MAXLINES = atoi(optarg)) < 1)
                        usage();
                    break;
#ifdef TRACE
                case 'T':
                    trace(atoi(optarg));
                    break;
                case 't':
                    trace(TRACE_CALLS);
                    break;
#endif
                default:
                    usage();
            }
    }
    if (optind + 1 != argc)
            usage();

    if ((my_lines = typeMalloc(CURSES_CH_T *, MAXLINES + 2)) == 0)
            usage();

    fname = argv[optind];
    if ((fp = fopen(fname, "r")) == 0) {
            perror(fname);
            exit( 1 );
    }

    /* slurp the file */
    num_lines = 0;
    for (lptr = &my_lines[0]; (lptr - my_lines) < MAXLINES; lptr++) {
            char temp[BUFSIZ], *s, *d;
            int col;

            if (fgets(buf, sizeof(buf), fp) == 0)
                break;

            /* convert tabs so that shift will work properly */
            for (s = buf, d = temp, col = 0; (*d = *s) != '\0'; s++) {
                if (*d == '\n') {
                        *d = '\0';
                        break;
                } else if (*d == '\t') {
                        col = (col | 7) + 1;
                        while ((d - temp) != col)
                            *d++ = ' ';
                } else
#ifdef HAVE_WCHAR
                        col++, d++;
#else
                    if (isprint(UChar(*d))) {
                            col++;
                            d++;
                    } else {
                            sprintf(d, "\\%03o", UChar(*s));
                            d += strlen(d);
                            col = (d - temp);
                    }
#endif
            }
            *lptr = ch_dup(temp);
            num_lines++;
    }
    (void) fclose(fp);
    length = lptr - my_lines;

    (void) initscr();           /* initialize the curses library */
    keypad(stdscr, TRUE);       /* enable keyboard mapping */
    (void) nonl();       /* tell curses not to do NL->CR/NL on output */
    (void) cbreak(); /* take input chars one at a time, no wait for \n */
    (void) noecho();            /* don't echo input */
    nodelay(stdscr, TRUE);
    idlok(stdscr, TRUE);        /* allow use of insert/delete line */

    if (try_color) {
            if (has_colors()) {
                start_color();
                init_pair(my_pair, COLOR_WHITE, COLOR_BLUE);
                bkgd(COLOR_PAIR(my_pair));
            } else {
                try_color = FALSE;
            }
    }

    lptr = my_lines;
    while (!done) {
            int n;
#ifdef HAVE_WCHAR
        wint_t c = 0;
        int ret;
#else
        int c = 0;
#endif /* HAVE_WCHAR */

            if (!got_number)
                show_all(my_label);

            n = 0;
            for (;;) {
            c = 0;
#ifdef HAVE_WCHAR
            ret = get_wch( &c );
            if ( ret == ERR ) {
                    if (!my_delay)
                            napms(50);
                continue;
            }
#ifdef DEBUG
            else if ( ret == KEY_CODE_YES )
                syslog( LOG_INFO, "[main]Func key(%x)", c );
            else
                syslog( LOG_INFO, "[main]c=%x", c );
#endif /* DEBUG */
#else
                c = getch();
#ifdef DEBUG
            syslog( LOG_INFO, "[main]c='%c'", c );
#endif /* DEBUG */
#endif /* HAVE_WCHAR */
                if ((c < 127) && isdigit(c)) {
                        if (!got_number) {
                            mvprintw(0, 0, "Count: ");
                            clrtoeol();
                        }
                        addch(c);
                        value = 10 * value + (c - '0');
                        got_number = TRUE;
                } else
                        break;
            }
            if (got_number && value) {
                n = value;
            } else {
                n = 1;
            }

#ifdef HAVE_WCHAR
            if (ret != ERR)
            my_label = key_name( c );
        else
                if (!my_delay)
                        napms(50);
#else
            if (c != ERR)
                my_label = keyname(c);
#endif /* HAVE_WCHAR */
            switch (c) {
                case KEY_DOWN:
#ifdef HAVE_WCHAR
            case L'n':
#else
                case 'n':
#endif /* HAVE_WCHAR */
                    olptr = lptr;
                    for (i = 0; i < n; i++)
                            if ((lptr - my_lines) < (length - LINES + 1))
                                lptr++;
                            else
                                break;
                    wscrl(stdscr, lptr - olptr);
                    break;

                case KEY_UP:
#ifdef HAVE_WCHAR
            case L'p':
#else
                case 'p':
#endif /* HAVE_WCHAR */
                    olptr = lptr;
                    for (i = 0; i < n; i++)
                            if (lptr > my_lines)
                                lptr--;
                            else
                                break;
                    wscrl(stdscr, lptr - olptr);
                    break;

#ifdef HAVE_WCHAR
            case L'h':
#else
                case 'h':
#endif /* HAVE_WCHAR */
                case KEY_HOME:
                    lptr = my_lines;
                    break;

#ifdef HAVE_WCHAR
            case L'e':
#else
                case 'e':
#endif /* HAVE_WCHAR */
                case KEY_END:
                    if (length > LINES)
                            lptr = my_lines + length - LINES + 1;
                    else
                            lptr = my_lines;
                    break;

#ifdef HAVE_WCHAR
            case L'r':
#else
                case 'r':
#endif /* HAVE_WCHAR */
                case KEY_RIGHT:
                    shift += n;
                    break;

#ifdef HAVE_WCHAR
            case L'l':
#else
                case 'l':
#endif /* HAVE_WCHAR */
                case KEY_LEFT:
                    shift -= n;
                    if (shift < 0) {
                            shift = 0;
                            beep();
                    }
                    break;

#ifdef HAVE_WCHAR
            case L'q':
#else
                case 'q':
#endif /* HAVE_WCHAR */
                    done = TRUE;
                    break;

#ifdef KEY_RESIZE
                case KEY_RESIZE:
                //refresh();
                    break;
#endif
#ifdef HAVE_WCHAR
                case L's':
#else
            case 's':
#endif /* HAVE_WCHAR */
                    if (got_number) {
                            halfdelay(my_delay = n);
                    } else {
                            nodelay(stdscr, FALSE);
                            my_delay = -1;
                    }
                    break;
#ifdef HAVE_WCHAR
            case L' ':
#else
                case ' ':
#endif /* HAVE_WCHAR */
                    nodelay(stdscr, TRUE);
                    my_delay = 0;
                    break;
#ifndef HAVE_WCHAR
                case ERR:
                    if (!my_delay)
                            napms(50);
                    break;
#endif /* HAVE_WCHAR */
                default:
                    beep();
                    break;
            }
            if (c >= KEY_MIN || (c > 0 && !isdigit(c))) {
                got_number = FALSE;
                value = 0;
            }
    }

    finish(0);                  /* we're done */
}

static void finish(int sig)
{
    endwin();
    exit(sig != 0 ?  1 : 0 );
}

static void show_all(const char *tag)
{
    int i;
    char temp[BUFSIZ];
    CURSES_CH_T *s;
    time_t this_time;

    sprintf(temp, "%s (%3dx%3d) col %d ", tag, LINES, COLS, shift);
    i = strlen(temp);
    sprintf(temp + i, "view %.*s", (int) (sizeof(temp) - 7 - i), fname);
    move(0, 0);
    printw("%.*s", COLS, temp);
    clrtoeol();
    this_time = time((time_t *) 0);
    strcpy(temp, ctime(&this_time));
    if ((i = strlen(temp)) != 0) {
            temp[--i] = 0;
            if (move(0, COLS - i - 2) != ERR)
                printw("  %s", temp);
    }

    scrollok(stdscr, FALSE);    /* prevent screen from moving */
    for (i = 1; i < LINES; i++) {
            move(i, 0);
            printw("%3ld:", (long) (lptr + i - my_lines));
            clrtoeol();
            if ((s = lptr[i - 1]) != 0) {
                    if (i < num_lines) {
                            int len = ch_len(s);
                            if (len > shift) {
#ifdef HAVE_WCHAR
                                    add_wchstr(s + shift);
#else
                                    addchstr(s + shift);
#endif
                            }
                    }
            }
    }
    setscrreg(1, LINES - 1);
    scrollok(stdscr, TRUE);
    refresh();
}