* Copyright © 2004 Kevin B. Kenny. All rights reserved.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 */

#include "tclInt.h"


/*
 * Windows has mktime. The configurators do not check.
 */

#ifdef _WIN32
#define HAVE_MKTIME 1

/*
 * Function prototypes for local procedures in this file:
 */

static int		ConvertUTCToLocal(Tcl_Interp *,
			    TclDateFields *, Tcl_Obj *, int);
static int		ConvertUTCToLocalUsingTable(Tcl_Interp *,
			    TclDateFields *, int, Tcl_Obj *const[]);
static int		ConvertUTCToLocalUsingC(Tcl_Interp *,
			    TclDateFields *, int);
static int		ConvertLocalToUTC(Tcl_Interp *,
			    TclDateFields *, Tcl_Obj *, int);
static int		ConvertLocalToUTCUsingTable(Tcl_Interp *,
			    TclDateFields *, int, Tcl_Obj *const[]);
static int		ConvertLocalToUTCUsingC(Tcl_Interp *,
			    TclDateFields *, int);
static Tcl_Obj *	LookupLastTransition(Tcl_Interp *, Tcl_WideInt,
			    int, Tcl_Obj *const *);
static void		GetYearWeekDay(TclDateFields *, int);
static void		GetGregorianEraYearDay(TclDateFields *, int);
static void		GetMonthDay(TclDateFields *);
static void		GetJulianDayFromEraYearWeekDay(TclDateFields *, int);
static void		GetJulianDayFromEraYearMonthDay(TclDateFields *, int);
static int		IsGregorianLeapYear(TclDateFields *);
static int		WeekdayOnOrBefore(int, int);
static int		ClockClicksObjCmd(
			    void *clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *const objv[]);
static int		ClockConvertlocaltoutcObjCmd(
			    void *clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *const objv[]);
static int		ClockGetdatefieldsObjCmd(
			    void *clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *const objv[]);
static int		ClockGetjuliandayfromerayearmonthdayObjCmd(
			    void *clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *const objv[]);
static int		ClockGetjuliandayfromerayearweekdayObjCmd(
			    void *clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *const objv[]);
static int		ClockGetenvObjCmd(
			    void *clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *const objv[]);
static int		ClockMicrosecondsObjCmd(
			    void *clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *const objv[]);
static int		ClockMillisecondsObjCmd(
			    void *clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *const objv[]);
static int		ClockParseformatargsObjCmd(
			    void *clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *const objv[]);
static int		ClockSecondsObjCmd(
			    void *clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *const objv[]);
static struct tm *	ThreadSafeLocalTime(const time_t *);
static void		TzsetIfNecessary(void);
static void		ClockDeleteCmdProc(ClientData);

/*
 * Structure containing description of "native" clock commands to create.
 */

struct ClockCommand {
    const char *name;		/* The tail of the command name. The full name

    }

    /*
     * fields.seconds could be an unsigned number that overflowed. Make sure
     * that it isn't.
     */

    if (TclHasInternalRep(objv[1], &tclBignumType)) {
	Tcl_SetObjResult(interp, lit[LIT_INTEGER_VALUE_TOO_LARGE]);
	return TCL_ERROR;
    }

    /*
     * Convert UTC time to local.
     */

static int
ConvertLocalToUTC(
    Tcl_Interp *interp,		/* Tcl interpreter */
    TclDateFields *fields,	/* Fields of the time */
    Tcl_Obj *tzdata,		/* Time zone data */
    int changeover)		/* Julian Day of the Gregorian transition */
{
    int rowc;			/* Number of rows in tzdata */
    Tcl_Obj **rowv;		/* Pointers to the rows */

    /*
     * Unpack the tz data.
     */

    if (TclListObjGetElements(interp, tzdata, &rowc, &rowv) != TCL_OK) {
	return TCL_ERROR;
    }

    /*
     * Special case: If the time zone is :localtime, the tzdata will be empty.
     * Use 'mktime' to convert the time to local
     */

 *----------------------------------------------------------------------
 */

static int
ConvertLocalToUTCUsingTable(
    Tcl_Interp *interp,		/* Tcl interpreter */
    TclDateFields *fields,	/* Time to convert, with 'seconds' filled in */
    int rowc,			/* Number of points at which time changes */
    Tcl_Obj *const rowv[])	/* Points at which time changes */
{
    Tcl_Obj *row;
    int cellc;
    Tcl_Obj **cellv;
    int have[8];
    int nHave = 0;
    int i;
    int found;

    /*

    found = 0;
    fields->tzOffset = 0;
    fields->seconds = fields->localSeconds;
    while (!found) {
	row = LookupLastTransition(interp, fields->seconds, rowc, rowv);
	if ((row == NULL)
		|| TclListObjGetElements(interp, row, &cellc,
		    &cellv) != TCL_OK
		|| TclGetIntFromObj(interp, cellv[1],
		    &fields->tzOffset) != TCL_OK) {
	    return TCL_ERROR;
	}
	found = 0;
	for (i = 0; !found && i < nHave; ++i) {

static int
ConvertUTCToLocal(
    Tcl_Interp *interp,		/* Tcl interpreter */
    TclDateFields *fields,	/* Fields of the time */
    Tcl_Obj *tzdata,		/* Time zone data */
    int changeover)		/* Julian Day of the Gregorian transition */
{
    int rowc;			/* Number of rows in tzdata */
    Tcl_Obj **rowv;		/* Pointers to the rows */

    /*
     * Unpack the tz data.
     */

    if (TclListObjGetElements(interp, tzdata, &rowc, &rowv) != TCL_OK) {
	return TCL_ERROR;
    }

    /*
     * Special case: If the time zone is :localtime, the tzdata will be empty.
     * Use 'localtime' to convert the time to local
     */

 *----------------------------------------------------------------------
 */

static int
ConvertUTCToLocalUsingTable(
    Tcl_Interp *interp,		/* Tcl interpreter */
    TclDateFields *fields,	/* Fields of the date */
    int rowc,			/* Number of rows in the conversion table
				 * (>= 1) */
    Tcl_Obj *const rowv[])	/* Rows of the conversion table */
{
    Tcl_Obj *row;		/* Row containing the current information */
    int cellc;			/* Count of cells in the row (must be 4) */
    Tcl_Obj **cellv;		/* Pointers to the cells */

    /*
     * Look up the nearest transition time.
     */

    row = LookupLastTransition(interp, fields->seconds, rowc, rowv);
    if (row == NULL ||
	    TclListObjGetElements(interp, row, &cellc, &cellv) != TCL_OK ||
	    TclGetIntFromObj(interp, cellv[1], &fields->tzOffset) != TCL_OK) {
	return TCL_ERROR;
    }

    /*
     * Convert the time.
     */

    fields->tzOffset = diff;
    if (diff < 0) {
	*buffer = '-';
	diff = -diff;
    } else {
	*buffer = '+';
    }
    sprintf(buffer+1, "%02d", diff / 3600);
    diff %= 3600;
    sprintf(buffer+3, "%02d", diff / 60);
    diff %= 60;
    if (diff > 0) {
	sprintf(buffer+5, "%02d", diff);
    }
    fields->tzName = Tcl_NewStringObj(buffer, -1);
    Tcl_IncrRefCount(fields->tzName);
    return TCL_OK;
}

/*

 *----------------------------------------------------------------------
 */

static Tcl_Obj *
LookupLastTransition(
    Tcl_Interp *interp,		/* Interpreter for error messages */
    Tcl_WideInt tick,		/* Time from the epoch */
    int rowc,			/* Number of rows of tzdata */
    Tcl_Obj *const *rowv)	/* Rows in tzdata */
{
    int l;
    int u;
    Tcl_Obj *compObj;
    Tcl_WideInt compVal;

    /*
     * Examine the first row to make sure we're in bounds.
     */

#if 0 /* BUG https://core.tcl-lang.org/tcl/tktview?name=da340d4f32 */
    ym1o4 = ym1 / 4;
#else
    /*
     * Have to make sure quotient is truncated towards 0 when negative.
     * See above bug for details. The casts are necessary.
     */
    if (ym1 >= 0)
	ym1o4 = ym1 / 4;
    else {
	ym1o4 = - (int) (((unsigned int) -ym1) / 4);
    }
#endif
    if (ym1 % 4 < 0) {
	ym1o4--;
    }
    ym1o100 = ym1 / 100;

ClockMillisecondsObjCmd(
    TCL_UNUSED(void *),
    Tcl_Interp *interp,		/* Tcl interpreter */
    int objc,			/* Parameter count */
    Tcl_Obj *const *objv)	/* Parameter values */
{
    Tcl_Time now;


    if (objc != 1) {
	Tcl_WrongNumArgs(interp, 1, objv, NULL);
	return TCL_ERROR;
    }
    Tcl_GetTime(&now);
    Tcl_SetObjResult(interp, Tcl_NewWideIntObj((Tcl_WideInt)
	    now.sec * 1000 + now.usec / 1000));

    return TCL_OK;
}

/*----------------------------------------------------------------------
 *
 * ClockMicrosecondsObjCmd -
 *

ClockSecondsObjCmd(
    TCL_UNUSED(void *),
    Tcl_Interp *interp,		/* Tcl interpreter */
    int objc,			/* Parameter count */
    Tcl_Obj *const *objv)	/* Parameter values */
{
    Tcl_Time now;


    if (objc != 1) {
	Tcl_WrongNumArgs(interp, 1, objv, NULL);
	return TCL_ERROR;
    }
    Tcl_GetTime(&now);


    Tcl_SetObjResult(interp, Tcl_NewWideIntObj((Tcl_WideInt) now.sec));
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TzsetIfNecessary --