// bbldc_calendardaycountutil.h                                       -*-C++-*-
#ifndef INCLUDED_BBLDC_CALENDARDAYCOUNTUTIL
#define INCLUDED_BBLDC_CALENDARDAYCOUNTUTIL

#include <bsls_ident.h>
BSLS_IDENT("$Id: $")

//@PURPOSE: Support for day-count calculations of `enum`-specified conventions.
//
//@CLASSES:
//  bbldc::CalendarDayCountUtil: `enum`-specified day-count calculations
//
//@SEE_ALSO: bbldc_daycountconvention, bbldc_calendarbus252
//
//@DESCRIPTION: This component provides a `struct`,
// `bbldc::CalendarDayCountUtil`, that defines a suite of date-related
// functions used to compute the day count and the year fraction between two
// dates as prescribed by an enumerated day-count convention.  Specifically,
// the `daysDiff` and `yearsDiff` methods defined in
// `bbldc::CalendarDayCountUtil` take a trailing `DayCountConvention::Enum`
// argument indicating which particular day-count convention to apply.
//
///Usage
///-----
// This section illustrates intended use of this component.
//
///Example 1: Computing Day Count and Year Fraction
/// - - - - - - - - - - - - - - - - - - - - - - - -
// The following snippets of code illustrate how to use
// `bbldc::CalendarDayCountUtil` methods.  First, create two `bdlt::Date`
// variables, `d1` and `d2`:
// ```
// const bdlt::Date d1(2003, 10, 19);
// const bdlt::Date d2(2003, 12, 31);
// ```
// Then, create a `calendar` with a valid range spanning 2003 and typical
// weekend days:
// ```
// bdlt::Calendar calendar;
// calendar.setValidRange(bdlt::Date(2003, 1, 1), bdlt::Date(2003, 12, 31));
// calendar.addWeekendDay(bdlt::DayOfWeek::e_SUN);
// calendar.addWeekendDay(bdlt::DayOfWeek::e_SAT);
// ```
// Now, compute the day count between `d1` and `d2` according to the BUS-252
// day-count convention:
// ```
// const int daysDiff = bbldc::CalendarDayCountUtil::daysDiff(
//                             d1,
//                             d2,
//                             calendar,
//                             bbldc::DayCountConvention::e_CALENDAR_BUS_252);
// assert(52 == daysDiff);
// ```
// Finally, compute the year fraction between the two dates according to the
// BUS-252 day-count convention:
// ```
// const double yearsDiff = bbldc::CalendarDayCountUtil::yearsDiff(
//                             d1,
//                             d2,
//                             calendar,
//                             bbldc::DayCountConvention::e_CALENDAR_BUS_252);
// // Need fuzzy comparison since 'yearsDiff' is a 'double'.
// assert(0.2063 < yearsDiff && 0.2064 > yearsDiff);
// ```

#include <bblscm_version.h>

#include <bbldc_daycountconvention.h>

#include <bdlt_calendar.h>
#include <bdlt_date.h>

namespace BloombergLP {
namespace bbldc {

                       // ===========================
                       // struct CalendarDayCountUtil
                       // ===========================

/// This `struct` provides a namespace for a suite of pure functions that
/// compute values based on dates according to enumerated day-count
/// conventions.
struct CalendarDayCountUtil {

    // CLASS METHODS

    /// Return the (signed) number of days between the specified `beginDate`
    /// and `endDate` according to the specified day-count `convention` with
    /// the specified `calendar` providing the definition of business days.
    /// If `beginDate <= endDate` then the result is non-negative.  The
    /// behavior is undefined unless `isSupported(convention)`,
    /// `calendar.isInRange(beginDate)`, and `calendar.isInRange(endDate)`.
    /// Note that reversing the order of `beginDate` and `endDate` negates
    /// the result and that the result is 0 when `beginDate == endDate`.
    static int daysDiff(const bdlt::Date&        beginDate,
                        const bdlt::Date&        endDate,
                        const bdlt::Calendar&    calendar,
                        DayCountConvention::Enum convention);

    /// Return `true` if the specified `convention` is valid for use in
    /// `daysDiff` and `yearsDiff`, and `false` otherwise.
    static bool isSupported(DayCountConvention::Enum convention);

    /// Return the (signed fractional) number of years between the specified
    /// `beginDate` and `endDate` according to the specified day-count
    /// `convention` with the specified `calendar` providing the definition
    /// of business days.  If `beginDate <= endDate` then the result is
    /// non-negative.  The behavior is undefined unless
    /// `isSupported(convention)`, `calendar.isInRange(beginDate)`, and
    /// `calendar.isInRange(endDate)`.  Note that reversing the order of
    /// `beginDate` and `endDate` negates the result; specifically,
    /// `|yearsDiff(b, e, cal, c) + yearsDiff(e, b, cal, c)| <= 1.0e-15` for
    /// all calendars `cal`, valid dates `b` and `e`, and day-count
    /// conventions `c`.
    static double yearsDiff(const bdlt::Date&        beginDate,
                            const bdlt::Date&        endDate,
                            const bdlt::Calendar&    calendar,
                            DayCountConvention::Enum convention);
};

}  // close package namespace
}  // close enterprise namespace

#endif

// ----------------------------------------------------------------------------
// Copyright 2015 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
