/*
*******************************************************************************
* Copyright (C) 2016, International Business Machines
* Corporation and others.  All Rights Reserved.
*******************************************************************************
* dayperiodrules.cpp
*
* created on: 2016-01-20
* created by: kazede
*/

#include "dayperiodrules.h"

#include "unicode/ures.h"
#include "charstr.h"
#include "cstring.h"
#include "ucln_in.h"
#include "uhash.h"
#include "umutex.h"
#include "uresimp.h"


U_NAMESPACE_BEGIN

namespace {

struct DayPeriodRulesData : public UMemory {
    DayPeriodRulesData() : localeToRuleSetNumMap(NULL), rules(NULL), maxRuleSetNum(0) {}

    UHashtable *localeToRuleSetNumMap;
    DayPeriodRules *rules;
    int32_t maxRuleSetNum;
} *data = NULL;

enum CutoffType {
    CUTOFF_TYPE_UNKNOWN = -1,
    CUTOFF_TYPE_BEFORE,
    CUTOFF_TYPE_AFTER,  // TODO: AFTER is deprecated in CLDR 29. Remove.
    CUTOFF_TYPE_FROM,
    CUTOFF_TYPE_AT
};

} // namespace

struct DayPeriodRulesDataSink : public ResourceTableSink {
    // Initialize sub-sinks.
    DayPeriodRulesDataSink() :
            rulesSink(*this), ruleSetSink(*this), periodSink(*this), cutoffSink(*this) {
        for (int32_t i = 0; i < UPRV_LENGTHOF(cutoffs); ++i) { cutoffs[i] = 0; }
    }
    virtual ~DayPeriodRulesDataSink();

    // Entry point.
    virtual ResourceTableSink *getOrCreateTableSink(const char *key, int32_t, UErrorCode &errorCode) {
        if (U_FAILURE(errorCode)) { return NULL; }

        if (uprv_strcmp(key, "locales") == 0) {
            return &localesSink;
        } else if (uprv_strcmp(key, "rules") == 0) {
            // Allocate one more than needed to skip [0]. See comment in parseSetNum().
            data->rules = new DayPeriodRules[data->maxRuleSetNum + 1];
            if (data->rules == NULL) {
                errorCode = U_MEMORY_ALLOCATION_ERROR;
                return NULL;
            } else {
                return &rulesSink;
            }
        }
        return NULL;
    }

    // Data root -> locales.
    struct LocalesSink : public ResourceTableSink {
        virtual ~LocalesSink();

        virtual void put(const char *key, const ResourceValue &value, UErrorCode &errorCode) {
            if (U_FAILURE(errorCode)) { return; }

            UnicodeString setNum_str = value.getUnicodeString(errorCode);
            int32_t setNum = parseSetNum(setNum_str, errorCode);
            uhash_puti(data->localeToRuleSetNumMap, const_cast<char *>(key), setNum, &errorCode);
        }
    } localesSink;

    // Data root -> rules.
    struct RulesSink : public ResourceTableSink {
        DayPeriodRulesDataSink &outer;
        RulesSink(DayPeriodRulesDataSink &outer) : outer(outer) {}
        virtual ~RulesSink();

        virtual ResourceTableSink *getOrCreateTableSink(const char *key, int32_t, UErrorCode &errorCode) {
            if (U_FAILURE(errorCode)) { return NULL; }

            outer.ruleSetNum = parseSetNum(key, errorCode);
            return &outer.ruleSetSink;
        }
    } rulesSink;

    // Data root -> rules -> a rule set.
    struct RuleSetSink : public ResourceTableSink {
        DayPeriodRulesDataSink &outer;
        RuleSetSink(DayPeriodRulesDataSink &outer) : outer(outer) {}
        virtual ~RuleSetSink();

        virtual ResourceTableSink *getOrCreateTableSink(const char *key, int32_t, UErrorCode &errorCode) {
            if (U_FAILURE(errorCode)) { return NULL; }

            outer.period = DayPeriodRules::getDayPeriodFromString(key);
            if (outer.period == DayPeriodRules::DAYPERIOD_UNKNOWN) {
                errorCode = U_INVALID_FORMAT_ERROR;
                return NULL;
            }

            return &outer.periodSink;
        }

        virtual void leave(UErrorCode &errorCode) {
            if (U_FAILURE(errorCode)) { return; }

            if (!data->rules[outer.ruleSetNum].allHoursAreSet()) {
                errorCode = U_INVALID_FORMAT_ERROR;
            }
        }
    } ruleSetSink;

    // Data root -> rules -> a rule set -> a period (e.g. "morning1").
    // Key-value pairs (e.g. before{6:00}) will be captured here.
    // Arrays (e.g. before{6:00, 24:00}) will be redirected to the next sink.
    struct PeriodSink : public ResourceTableSink {
        DayPeriodRulesDataSink &outer;
        PeriodSink(DayPeriodRulesDataSink &outer) : outer(outer) {}
        virtual ~PeriodSink();

        virtual void put(const char *key, const ResourceValue &value, UErrorCode &errorCode) {
            if (U_FAILURE(errorCode)) { return; }

            CutoffType type = getCutoffTypeFromString(key);
            outer.addCutoff(type, value.getUnicodeString(errorCode), errorCode);
        }

        virtual ResourceArraySink *getOrCreateArraySink(const char *key, int32_t, UErrorCode &errorCode) {
            if (U_FAILURE(errorCode)) { return NULL; }
            outer.cutoffType = getCutoffTypeFromString(key);
            return &outer.cutoffSink;
        }

        virtual void leave(UErrorCode &errorCode) {
            if (U_FAILURE(errorCode)) { return; }

            outer.setDayPeriodForHoursFromCutoffs(errorCode);
            for (int32_t i = 0; i < UPRV_LENGTHOF(outer.cutoffs); ++i) {
                outer.cutoffs[i] = 0;
            }
        }
    } periodSink;

    // Data root -> rules -> a rule set -> a period -> a cutoff type.
    // Will enter this sink if 2+ times appear in a single cutoff type (e.g. before{6:00, 24:00}).
    struct CutoffSink : public ResourceArraySink {
        DayPeriodRulesDataSink &outer;
        CutoffSink(DayPeriodRulesDataSink &outer) : outer(outer) {}
        virtual ~CutoffSink();

        virtual void put(int32_t, const ResourceValue &value, UErrorCode &errorCode) {
            outer.addCutoff(outer.cutoffType, value.getUnicodeString(errorCode), errorCode);
        }
    } cutoffSink;

    // Members.
    int32_t cutoffs[25];  // [0] thru [24]: 24 is allowed in "before 24".

    // "Path" to data.
    int32_t ruleSetNum;
    DayPeriodRules::DayPeriod period;
    CutoffType cutoffType;

    // Helpers.
    static int32_t parseSetNum(const UnicodeString &setNumStr, UErrorCode &errorCode) {
        CharString cs;
        cs.appendInvariantChars(setNumStr, errorCode);
        return parseSetNum(cs.data(), errorCode);
    }

    static int32_t parseSetNum(const char *setNumStr, UErrorCode &errorCode) {
        if (U_FAILURE(errorCode)) { return -1; }

        if (uprv_strncmp(setNumStr, "set", 3) != 0) {
            errorCode = U_INVALID_FORMAT_ERROR;
            return -1;
        }

        int32_t i = 3;
        int32_t setNum = 0;
        while (setNumStr[i] != 0) {
            int32_t digit = setNumStr[i] - '0';
            if (digit < 0 || 9 < digit) {
                errorCode = U_INVALID_FORMAT_ERROR;
                return -1;
            }
            setNum = 10 * setNum + digit;
            ++i;
        }

        // Rule set number must not be zero. (0 is used to indicate "not found" by hashmap.)
        // Currently ICU data conveniently starts numbering rule sets from 1.
        if (setNum == 0) {
            errorCode = U_INVALID_FORMAT_ERROR;
            return -1;
        } else {
            return setNum;
        }
    }

    void addCutoff(CutoffType type, UnicodeString hour_str, UErrorCode &errorCode) {
        if (U_FAILURE(errorCode)) { return; }

        if (type == CUTOFF_TYPE_UNKNOWN) {
            errorCode = U_INVALID_FORMAT_ERROR;
            return;
        }

        int32_t hour = parseHour(hour_str, errorCode);
        if (U_FAILURE(errorCode)) { return; }

        cutoffs[hour] |= 1 << type;
    }

    // Translate the cutoffs[] array to day period rules.
    void setDayPeriodForHoursFromCutoffs(UErrorCode &errorCode) {
        DayPeriodRules &rule = data->rules[ruleSetNum];

        for (int32_t startHour = 0; startHour <= 24; ++startHour) {
            // AT cutoffs must be either midnight or noon.
            if (cutoffs[startHour] & (1 << CUTOFF_TYPE_AT)) {
                if (startHour == 0 && period == DayPeriodRules::DAYPERIOD_MIDNIGHT) {
                    rule.fHasMidnight = TRUE;
                } else if (startHour == 12 && period == DayPeriodRules::DAYPERIOD_NOON) {
                    rule.fHasNoon = TRUE;
                } else {
                    errorCode = U_INVALID_FORMAT_ERROR;  // Bad data.
                    return;
                }
            }

            // FROM/AFTER and BEFORE must come in a pair.
            if (cutoffs[startHour] & (1 << CUTOFF_TYPE_FROM) ||
                    cutoffs[startHour] & (1 << CUTOFF_TYPE_AFTER)) {
                for (int32_t hour = startHour + 1;; ++hour) {
                    if (hour == startHour) {
                        // We've gone around the array once and can't find a BEFORE.
                        errorCode = U_INVALID_FORMAT_ERROR;
                        return;
                    }
                    if (hour == 25) { hour = 0; }
                    if (cutoffs[hour] & (1 << CUTOFF_TYPE_BEFORE)) {
                        rule.add(startHour, hour, period);
                        break;
                    }
                }
            }
        }
    }

    // Translate "before" to CUTOFF_TYPE_BEFORE, for example.
    static CutoffType getCutoffTypeFromString(const char *type_str) {
        if (uprv_strcmp(type_str, "from") == 0) {
            return CUTOFF_TYPE_FROM;
        } else if (uprv_strcmp(type_str, "before") == 0) {
            return CUTOFF_TYPE_BEFORE;
        } else if (uprv_strcmp(type_str, "after") == 0) {
            return CUTOFF_TYPE_AFTER;
        } else if (uprv_strcmp(type_str, "at") == 0) {
            return CUTOFF_TYPE_AT;
        } else {
            return CUTOFF_TYPE_UNKNOWN;
        }
    }

    // Gets the numerical value of the hour from the Unicode string.
    static int32_t parseHour(const UnicodeString &time, UErrorCode &errorCode) {
        if (U_FAILURE(errorCode)) {
            return 0;
        }

        int32_t hourLimit = time.length() - 3;
        // `time` must look like "x:00" or "xx:00".
        // If length is wrong or `time` doesn't end with ":00", error out.
        if ((hourLimit != 1 && hourLimit != 2) ||
                time[hourLimit] != 0x3A || time[hourLimit + 1] != 0x30 ||
                time[hourLimit + 2] != 0x30) {
            errorCode = U_INVALID_FORMAT_ERROR;
            return 0;
        }

        // If `time` doesn't begin with a number in [0, 24], error out.
        // Note: "24:00" is possible in "before 24:00".
        int32_t hour = time[0] - 0x30;
        if (hour < 0 || 9 < hour) {
            errorCode = U_INVALID_FORMAT_ERROR;
            return 0;
        }
        if (hourLimit == 2) {
            int32_t hourDigit2 = time[1] - 0x30;
            if (hourDigit2 < 0 || 9 < hourDigit2) {
                errorCode = U_INVALID_FORMAT_ERROR;
                return 0;
            }
            hour = hour * 10 + hourDigit2;
            if (hour > 24) {
                errorCode = U_INVALID_FORMAT_ERROR;
                return 0;
            }
        }

        return hour;
    }
};  // struct DayPeriodRulesDataSink

struct DayPeriodRulesCountSink : public ResourceTableSink {
    virtual ~DayPeriodRulesCountSink();
    virtual ResourceTableSink *getOrCreateTableSink(const char *key, int32_t, UErrorCode &errorCode) {
        if (U_FAILURE(errorCode)) { return NULL; }

        int32_t setNum = DayPeriodRulesDataSink::parseSetNum(key, errorCode);
        if (setNum > data->maxRuleSetNum) {
            data->maxRuleSetNum = setNum;
        }

        return NULL;
    }
};

// Out-of-line virtual destructors.
DayPeriodRulesDataSink::LocalesSink::~LocalesSink() {}
DayPeriodRulesDataSink::CutoffSink::~CutoffSink() {}
DayPeriodRulesDataSink::PeriodSink::~PeriodSink() {}
DayPeriodRulesDataSink::RuleSetSink::~RuleSetSink() {}
DayPeriodRulesDataSink::RulesSink::~RulesSink() {}
DayPeriodRulesDataSink::~DayPeriodRulesDataSink() {}

DayPeriodRulesCountSink::~DayPeriodRulesCountSink() {}

namespace {

UInitOnce initOnce = U_INITONCE_INITIALIZER;

UBool dayPeriodRulesCleanup() {
    delete[] data->rules;
    uhash_close(data->localeToRuleSetNumMap);
    delete data;
    data = NULL;
    return TRUE;
}

}  // namespace

void DayPeriodRules::load(UErrorCode &errorCode) {
    if (U_FAILURE(errorCode)) {
        return;
    }

    data = new DayPeriodRulesData();
    data->localeToRuleSetNumMap = uhash_open(uhash_hashChars, uhash_compareChars, NULL, &errorCode);
    LocalUResourceBundlePointer rb_dayPeriods(ures_openDirect(NULL, "dayPeriods", &errorCode));

    // Get the largest rule set number (so we allocate enough objects).
    DayPeriodRulesCountSink countSink;
    ures_getAllTableItemsWithFallback(rb_dayPeriods.getAlias(), "rules", countSink, errorCode);

    // Populate rules.
    DayPeriodRulesDataSink sink;
    ures_getAllTableItemsWithFallback(rb_dayPeriods.getAlias(), "", sink, errorCode);

    ucln_i18n_registerCleanup(UCLN_I18N_DAYPERIODRULES, dayPeriodRulesCleanup);
}

const DayPeriodRules *DayPeriodRules::getInstance(const Locale &locale, UErrorCode &errorCode) {
    umtx_initOnce(initOnce, DayPeriodRules::load, errorCode);

    // If the entire day period rules data doesn't conform to spec (even if the part we want
    // does), return NULL.
    if(U_FAILURE(errorCode)) { return NULL; }

    const char *localeCode = locale.getName();
    char name[ULOC_FULLNAME_CAPACITY];
    char parentName[ULOC_FULLNAME_CAPACITY];

    if (uprv_strlen(localeCode) < ULOC_FULLNAME_CAPACITY) {
        uprv_strcpy(name, localeCode);

        // Treat empty string as root.
        if (*name == '\0') {
            uprv_strcpy(name, "root");
        }
    } else {
        errorCode = U_BUFFER_OVERFLOW_ERROR;
        return NULL;
    }

    int32_t ruleSetNum = 0;  // NB there is no rule set 0 and 0 is returned upon lookup failure.
    while (*name != '\0') {
        ruleSetNum = uhash_geti(data->localeToRuleSetNumMap, name);
        if (ruleSetNum == 0) {
            // name and parentName can't be the same pointer, so fill in parent then copy to child.
            uloc_getParent(name, parentName, ULOC_FULLNAME_CAPACITY, &errorCode);
            if (*parentName == '\0') {
                // Saves a lookup in the hash table.
                break;
            }
            uprv_strcpy(name, parentName);
        } else {
            break;
        }
    }

    if (ruleSetNum <= 0 || data->rules[ruleSetNum].getDayPeriodForHour(0) == DAYPERIOD_UNKNOWN) {
        // If day period for hour 0 is UNKNOWN then day period for all hours are UNKNOWN.
        // Data doesn't exist even with fallback.
        return NULL;
    } else {
        return &data->rules[ruleSetNum];
    }
}

DayPeriodRules::DayPeriodRules() : fHasMidnight(FALSE), fHasNoon(FALSE) {
    for (int32_t i = 0; i < 24; ++i) {
        fDayPeriodForHour[i] = DayPeriodRules::DAYPERIOD_UNKNOWN;
    }
}

double DayPeriodRules::getMidPointForDayPeriod(
        DayPeriodRules::DayPeriod dayPeriod, UErrorCode &errorCode) const {
    if (U_FAILURE(errorCode)) { return -1; }

    int32_t startHour = getStartHourForDayPeriod(dayPeriod, errorCode);
    int32_t endHour = getEndHourForDayPeriod(dayPeriod, errorCode);
    // Can't obtain startHour or endHour; bail out.
    if (U_FAILURE(errorCode)) { return -1; }

    double midPoint = (startHour + endHour) / 2.0;

    if (startHour > endHour) {
        // dayPeriod wraps around midnight. Shift midPoint by 12 hours, in the direction that
        // lands it in [0, 24).
        midPoint += 12;
        if (midPoint >= 24) {
            midPoint -= 24;
        }
    }

    return midPoint;
}

int32_t DayPeriodRules::getStartHourForDayPeriod(
        DayPeriodRules::DayPeriod dayPeriod, UErrorCode &errorCode) const {
    if (U_FAILURE(errorCode)) { return -1; }

    if (dayPeriod == DAYPERIOD_MIDNIGHT) { return 0; }
    if (dayPeriod == DAYPERIOD_NOON) { return 12; }

    if (fDayPeriodForHour[0] == dayPeriod && fDayPeriodForHour[23] == dayPeriod) {
        // dayPeriod wraps around midnight. Start hour is later than end hour.
        for (int32_t i = 22; i >= 1; --i) {
            if (fDayPeriodForHour[i] != dayPeriod) {
                return (i + 1);
            }
        }
    } else {
        for (int32_t i = 0; i <= 23; ++i) {
            if (fDayPeriodForHour[i] == dayPeriod) {
                return i;
            }
        }
    }

    // dayPeriod doesn't exist in rule set; set error and exit.
    errorCode = U_ILLEGAL_ARGUMENT_ERROR;
    return -1;
}

int32_t DayPeriodRules::getEndHourForDayPeriod(
        DayPeriodRules::DayPeriod dayPeriod, UErrorCode &errorCode) const {
    if (U_FAILURE(errorCode)) { return -1; }

    if (dayPeriod == DAYPERIOD_MIDNIGHT) { return 0; }
    if (dayPeriod == DAYPERIOD_NOON) { return 12; }

    if (fDayPeriodForHour[0] == dayPeriod && fDayPeriodForHour[23] == dayPeriod) {
        // dayPeriod wraps around midnight. End hour is before start hour.
        for (int32_t i = 1; i <= 22; ++i) {
            if (fDayPeriodForHour[i] != dayPeriod) {
                // i o'clock is when a new period starts, therefore when the old period ends.
                return i;
            }
        }
    } else {
        for (int32_t i = 23; i >= 0; --i) {
            if (fDayPeriodForHour[i] == dayPeriod) {
                return (i + 1);
            }
        }
    }

    // dayPeriod doesn't exist in rule set; set error and exit.
    errorCode = U_ILLEGAL_ARGUMENT_ERROR;
    return -1;
}

DayPeriodRules::DayPeriod DayPeriodRules::getDayPeriodFromString(const char *type_str) {
    if (uprv_strcmp(type_str, "midnight") == 0) {
        return DAYPERIOD_MIDNIGHT;
    } else if (uprv_strcmp(type_str, "noon") == 0) {
        return DAYPERIOD_NOON;
    } else if (uprv_strcmp(type_str, "morning1") == 0) {
        return DAYPERIOD_MORNING1;
    } else if (uprv_strcmp(type_str, "afternoon1") == 0) {
        return DAYPERIOD_AFTERNOON1;
    } else if (uprv_strcmp(type_str, "evening1") == 0) {
        return DAYPERIOD_EVENING1;
    } else if (uprv_strcmp(type_str, "night1") == 0) {
        return DAYPERIOD_NIGHT1;
    } else if (uprv_strcmp(type_str, "morning2") == 0) {
        return DAYPERIOD_MORNING2;
    } else if (uprv_strcmp(type_str, "afternoon2") == 0) {
        return DAYPERIOD_AFTERNOON2;
    } else if (uprv_strcmp(type_str, "evening2") == 0) {
        return DAYPERIOD_EVENING2;
    } else if (uprv_strcmp(type_str, "night2") == 0) {
        return DAYPERIOD_NIGHT2;
    } else if (uprv_strcmp(type_str, "am") == 0) {
        return DAYPERIOD_AM;
    } else if (uprv_strcmp(type_str, "pm") == 0) {
        return DAYPERIOD_PM;
    } else {
        return DAYPERIOD_UNKNOWN;
    }
}

void DayPeriodRules::add(int32_t startHour, int32_t limitHour, DayPeriod period) {
    for (int32_t i = startHour; i != limitHour; ++i) {
        if (i == 24) { i = 0; }
        fDayPeriodForHour[i] = period;
    }
}

UBool DayPeriodRules::allHoursAreSet() {
    for (int32_t i = 0; i < 24; ++i) {
        if (fDayPeriodForHour[i] == DAYPERIOD_UNKNOWN) { return FALSE; }
    }

    return TRUE;
}


U_NAMESPACE_END