// © 2018 and later: Unicode, Inc. and others.

// License & terms of use: http://www.unicode.org/copyright.html

#ifndef ERARULES_H_

#define ERARULES_H_

#include "unicode/utypes.h"

#if !UCONFIG_NO_FORMATTING

#include "unicode/localpointer.h"

#include "unicode/uobject.h"

#include "unicode/unistr.h"

#include "cmemory.h"

#define MAX_CAL_ID_LENGTH 31    // Currently, maximum calendar type length is 19 

U_NAMESPACE_BEGIN

class U_I18N_API_CLASS EraRules : public UMemory {

public:

    U_I18N_API ~EraRules();

    U_I18N_API static EraRules* createInstance(const char* calType,

                                               UBool includeTentativeEra,

                                               UErrorCode& status);

    /**

     * Gets the calendar type ID

     * @return  calendar type ID

     */

    inline const char* getCalendarType() const {

        return calTypeId;

    }

    /**

     * Gets the era rules of the calendar from which the current calendar inherits eras,

     * or nullptr if there is no such calendar.

     * @return  era rules of the calendar from which the current calendar inherits eras,

     * or nullptr.

     */

    inline const EraRules* getInheritEraRules() const {

        return inheritEraRules;

    }

    /**

     * Gets number of effective eras

     * @return  number of effective eras (not the same as max era code)

     */

    inline int32_t getNumberOfEras() const {

        return inheritEraRules == nullptr ? numEras : numEras + inheritEraRules->getNumberOfEras();

    }

    /**

     * Gets maximum defined era code for the current calendar

     * @return  maximum defined era code

     */

    inline int32_t getMaxEraCode() const {

        return minEra + startDatesLength - 1;

    }

    /**

     * Gets minimum defined era code for the current calendar

     * @return  minimum defined era code

     */

    inline int32_t getMinEraCode() const {

        int minEraCode = minEra;

        if (inheritEraRules != nullptr) {

            minEraCode = inheritEraRules->getMinEraCode();

        }

        return minEraCode;

    }

    /**

     * Gets next era code

     * @param eraCode Current era code

     * @return Next era code. If not available, maximum era code is returned.

     */

    U_I18N_API int32_t getNextEraCode(int32_t eraCode) const;

    /**

     * Gets start date of an era

     * @param eraCode   Era code

     * @param fields    Receives date fields. The result includes values of year, month,

     *                  day of month in this order. When an era has no start date, the result

     *                  will be January 1st in year whose value is minimum integer.

     * @param status    Receives status.

     */

    U_I18N_API void getStartDate(int32_t eraCode, int32_t (&fields)[3], UErrorCode& status) const;

    /**

     * Gets start year of an era

     * @param eraCode   Era code

     * @param status    Receives status.

     * @return The first year of an era. When a era has no start date, minimum int32

     *          value is returned.

     */

    U_I18N_API int32_t getStartYear(int32_t eraCode, UErrorCode& status) const;

    /**

     * Returns era code for the specified year/month/day.

     * @param year  Year

     * @param month Month (1-base)

     * @param day   Day of month

     * @param status    Receives status

     * @return  era code (or code of earliest era when date is before that era)

     */

    U_I18N_API int32_t getEraCode(int32_t year, int32_t month, int32_t day, UErrorCode& status) const;

    /**

     * Gets the current era code. This is calculated only once for an instance of

     * EraRules. The current era calculation is based on the default time zone at

     * the time of instantiation.

     *

     * @return era code of current era (or era code of earliest era when current date is before any era)

     */

    inline int32_t getCurrentEraCode() const {

        return currentEra;

    }

private:

    EraRules(const char* calTypeId, LocalMemory<int32_t>& startDatesIn, int32_t startDatesLengthIn,

        int32_t minEraIn, int32_t numErasIn);

    void initCurrentEra();

    char calTypeId[MAX_CAL_ID_LENGTH + 1];  // calendar type id

    LocalMemory<int32_t> startDates;

    int32_t startDatesLength;

    int32_t minEra;  // minimum valid era code, for first entry in startDates

    int32_t numEras; // number of valid era codes (not necessarily the same as startDates length

    int32_t currentEra;

    EraRules* inheritEraRules;

};

U_NAMESPACE_END

#endif /* #if !UCONFIG_NO_FORMATTING */

#endif /* ERARULES_H_ */