/* ------------- calendar.c ------------- */
#include <string.h>
#include <sys\types.h>
#include <time.h>


#include "dflatp.h"
#include "dfptools.h"
#include "edit.h"


/* #ifndef TURBOC */
#ifndef NOCALENDAR

#define CALHEIGHT 17
#define CALWIDTH 33

static int DyMo[] = {31,28,31,30,31,30,31,31,30,31,30,31};
static struct tm ttm, ctm;
static int dys[42];
static WINDOW Cwnd;

#ifndef strftime
static char * nameOfMonth[12] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
#endif

/* returns 1 if year (0-based, not 1900-based) is a leap year (longer) */
/* -ea */
int isLeapYear(int year)
{
  if (!(year % 400))
    return 1; /* e.g. 2000 is a leap year */
  if (!(year % 100))
    return 0; /* e.g. 1900 and 2100 are not */
  if (!(year % 4))
    return 1; /* multiple of 4? Then it is a leap year */
  return 0;   /* default: not a leap year */
}

/* Fixes ttm.tm_mday for a given month and year,
 * and recomputes the day of week and day of year
 * values, as ANSI C mktime() does. Turbo C 2.01
 * has no mktime(), so...
 * (tm_mday, tm_mon, tm_year -> tm_wday, tm_yday).
 * wday 0: Sunday. yday 0: Jan 1st. year 0: 1900.
 * mon 0: Jan. Contributed by Eric Auer.
 */
static void FixDate(void)
{
    int i,j;
    /* ---- adjust Feb for leap year ---- */
    DyMo[1] = isLeapYear(1900 + ttm.tm_year) ? 29 : 28;

    /* enforce ranges: 1..?? for mday, 0..11 for mon */
    /* (old version just clipped mday value...) -ea  */
    while (ttm.tm_mday > DyMo[ttm.tm_mon]) {
        ttm.tm_mday -= DyMo[ttm.tm_mon];
        ttm.tm_mon++;
        if (ttm.tm_mon > 11) {
            ttm.tm_mon = 0;
            ttm.tm_year++;
        }
    }

    /* re-calculate yday in 0..??? range */
    ttm.tm_yday = 0;
    i = 0;
    while (i < ttm.tm_mon) {
        ttm.tm_yday += DyMo[i];
        i++;
    }
    ttm.tm_yday += ttm.tm_mday - 1; /* mday is 1 based! */

   /* 1st of January of 1900 (tm_year base) was a Monday (wday = 1) */
   i = 0; /* year-1900 */
   j = 1; /* wday of Jan 1 1900: Monday */
   if (ttm.tm_year >= 1980) { /* leap closer: DOS epoch shortcut */
       i = 80;	/* start scanning from 1980 */
       j = 2;	/* Jan 1 1980 was a Tuesday */
   }
   while (i < ttm.tm_year) {
     j += isLeapYear(i+1900) ? 2 : 1; /* shift 1 or 2 days each year */
     if (j>6)
         j -= 7; /* wrap back in range */
     i++;
   }
   ttm.tm_wday = (j + ttm.tm_yday) % 7; /* "day of year" helps us! */
}

/* ---- build calendar dates array ---- */
static void BuildDateArray(void)
{
    int offset, dy = 0;
    memset(dys, 0, sizeof dys);
    FixDate();
    /* ----- compute the weekday for the 1st ----- */
    offset = ((ttm.tm_mday-1) - ttm.tm_wday) % 7;
    if (offset < 0)
        offset += 7;
    if (offset)
        offset = (offset - 7) * -1;
    /* ----- build the dates into the array ---- */
    for (dy = 1; dy <= DyMo[ttm.tm_mon]; dy++)
        dys[offset++] = dy;
}

static void CreateWindowMsg(WINDOW wnd)
{
    int x, y;
    DrawBox(wnd, 1, 2, CALHEIGHT-4, CALWIDTH-4);
    for (x = 5; x < CALWIDTH-4; x += 4)
        DrawVector(wnd, x, 2, CALHEIGHT-4, FALSE);
    for (y = 4; y < CALHEIGHT-3; y+=2)
        DrawVector(wnd, 1, y, CALWIDTH-4, TRUE);
}

static void DisplayDates(WINDOW wnd)
{
    int week, day;
    char dyln[10];
    int offset;
    char banner[CALWIDTH-1];
    char banner1[30];

    SetStandardColor(wnd);
    PutWindowLine(wnd, "Sun Mon Tue Wed Thu Fri Sat", 2, 1);
    memset(banner, ' ', CALWIDTH-2);

#ifndef strftime /* why was this disabled? */
    sprintf(banner1, "%s, %i", nameOfMonth[ttm.tm_mon], 1900+ttm.tm_year);
#else
    strftime(banner1, 16, "%B, %Y", &ttm);
#endif

    offset = (CALWIDTH-2 - strlen(banner1)) / 2;
    strcpy(banner+offset, banner1);
    strcat(banner, "    ");
    PutWindowLine(wnd, banner, 0, 0);
    BuildDateArray();
    for (week = 0; week < 6; week++)    {
        for (day = 0; day < 7; day++)    {
            int dy = dys[week*7+day];
            if (dy == 0)
                strcpy(dyln, "   ");
            else    {
                sprintf(dyln, "%2d ", dy);
            }
            if ( (dy == ctm.tm_mday) && (ctm.tm_mon == ttm.tm_mon) )
               SetReverseColor(wnd);
            else
               SetStandardColor(wnd);

            PutWindowLine(wnd, dyln, 2 + day * 4, 3 + week*2);
        }
    }
}

static int KeyboardMsg(WINDOW wnd, PARAM p1)
{
    switch ((int)p1)    {
        case PGUP:
            if (ttm.tm_mon == 0)    {
                ttm.tm_mon = 12;
                ttm.tm_year--;
            }
            ttm.tm_mon--;
            FixDate();
            DisplayDates(wnd);
            return TRUE;
        case PGDN:
            ttm.tm_mon++;
            if (ttm.tm_mon == 12)    {
                ttm.tm_mon = 0;
                ttm.tm_year++;
            }
            FixDate();
            DisplayDates(wnd);
            return TRUE;
        default:
            break;
    }
    return FALSE;
}

static int CalendarProc(WINDOW wnd,MESSAGE msg,
                                PARAM p1,PARAM p2)
{
    switch (msg)    {
        case CREATE_WINDOW:
            DefaultWndProc(wnd, msg, p1, p2);
            CreateWindowMsg(wnd);
            return TRUE;
        case KEYBOARD:
            if (KeyboardMsg(wnd, p1))
                return TRUE;
            break;
        case PAINT:
            DefaultWndProc(wnd, msg, p1, p2);
            DisplayDates(wnd);
            return TRUE;
        case COMMAND:
            if ((int)p1 == ID_HELP)    {
                DisplayHelp(wnd, "Calendar");
                return TRUE;
            }
            break;
        case CLOSE_WINDOW:
            Cwnd = NULL;
            break;
        default:
            break;
    }
    return DefaultWndProc(wnd, msg, p1, p2);
}

void Calendar(WINDOW pwnd)
{
    if (Cwnd == NULL)    {
        time_t tim = time(NULL);
        ttm = *localtime(&tim);
        ctm = ttm;  /* store current calendar day and month */
        Cwnd = CreateWindow(PICTUREBOX,
                    "Calendar (close: ctrl-F4)",
                    -1, -1, CALHEIGHT, CALWIDTH,
                    NULL, pwnd, CalendarProc,
                    SHADOW     |
                    MINMAXBOX  |
                    CONTROLBOX |
                    MOVEABLE   |
                    HASBORDER
        );
    }
    SendMessage(Cwnd, SETFOCUS, TRUE, 0);
}

#endif