#include "postgres.h"
#include "fmgr.h"
#include "executor/spi.h"
#include "utils/date.h"
#include "utils/builtins.h"
#include "isda/dateconv.h"
#include "isda/busday.h"

PG_MODULE_MAGIC;

static inline TDate next_business_day(TDate date, long method, const char* cal) {
    TDate r;
    if (JpmcdsBusinessDay(date, method, cal, &r) != SUCCESS) {
        return -1;
    } else {
        return r;
    }
}

TDate _previous_twentieth(TDate d, bool roll, const char* cal) {
    TMonthDayYear mdy;
    if (JpmcdsDateToMDY(d, &mdy) != SUCCESS) {
        return -1;
    }
    if (mdy.day < 20) {
        if(mdy.month == 1) {
            mdy.month = 12;
            mdy.year -= 1;
        } else {
            mdy.month -= 1;
        }
    }
    mdy.day = 20;
    int mod = mdy.month % 3;
    if (mod != 0) {
        mdy.month -= mod;
        if (mdy.month <= 0) {
            mdy.month += 12;
            mdy.year -= 1;
        }
    }
    TDate r;
    if (JpmcdsMDYToDate(&mdy, &r) != SUCCESS) {
        return -1;
    }
    if (roll) {
        return next_business_day(r, JPMCDS_BAD_DAY_FOLLOW, cal);
    } else {
        return r;
    }
}

// postgresql represents dates as number of days since 2000-01-01
// TDate are integers since 1601-01-01
static inline TDate TDate_from_DateADT(DateADT d) {
    return d + 145731;
}

static inline const char* cal_from_currency(const char* curr) {
    static const char default_cal[] = "NONE";
    static const char us_cal[] = "/usr/share/cds/US";
    if (strcmp(curr, "USD") == 0) {
        return us_cal;
    } else {
        return default_cal;
    }
}
PG_FUNCTION_INFO_V1(cds_accrued);

Datum cds_accrued(PG_FUNCTION_ARGS) {
    DateADT d = PG_GETARG_DATEADT(0);
    float8 coupon = PG_GETARG_FLOAT8(1);
    bool include_cashflow = PG_GETARG_BOOL(2);
    char* currency = text_to_cstring(PG_GETARG_TEXT_PP(3));
    const char* cal = cal_from_currency(currency);
    TDate date = TDate_from_DateADT(d) + 1;
    TDate date1 = next_business_day(date, JPMCDS_BAD_DAY_PREVIOUS, cal);
    if (date1 == -1)
        elog(ERROR, "Please set up the US calendar in /usr/share/cds/US");

    TDate date_prev = _previous_twentieth(date1, true, cal);

    if ((date_prev == date) && include_cashflow) {
        date_prev = _previous_twentieth(date - 1, true, cal);
    }
    pfree(currency);
    PG_RETURN_FLOAT8((date - date_prev) / 360. * coupon);
}


PG_FUNCTION_INFO_V1(test);

Datum cds_enrich(PG_FUNCTION_ARGS) {
    if (SPI_connect() == SPI_ERROR_CONNECT) {
        elog(ERROR, "pomme");
    }
    const text* redindexcode = PG_GETARG_TEXT_PP(0);
    DateADT maturity = PG_GETARG_DATEADT(1);
    float8 traded_level = PG_GETARG_FLOAT8(2);
    DateADT trade_datge = PG_GETARG_DATEADT(3);
    char* sql_query = "SELECT index, series, tenor::text, coupon, issue_date, indexfactor/100, "
        "version, cumulativeloss "
        "FROM index_desc "
        "WHERE redindexcode=$1 AND maturity=$2";
    int ret;
    uint64 proc;
    int nargs = 2;
    Oid argtypes[2] = {TEXTOID, DATEOID};
    char nulls[2] = "  ";
    Datum values[2];
    values[0] = PointerGetDatum(redindexcode);
    values[1] = DateADTGetDatum(maturity);
    ret = SPI_execute_with_args(sql_query, nargs, argtypes, values, nulls, true, 1);
    proc = SPI_processed;
    short series, version;
    int coupon;
    char *index, *tenor;
    TDate issue_date;
    double factor, cumulativeloss;
    if (ret == SPI_OK_SELECT && SPI_tuptable != NULL) {
        SPITupleTable *tuptable = SPI_tuptable;
        TupleDesc tupdesc = tuptable->tupdesc;
        bool isnull;
        HeapTuple tuple = tuptable->vals[0];
        index = text_to_cstring(DatumGetTextPP(SPI_getbinval(tuple, tupdesc, 1, &isnull)));
        series = DatumGetInt16(SPI_getbinval(tuple, tupdesc, 2, &isnull));
        tenor = text_to_cstring(DatumGetTextPP(SPI_getbinval(tuple, tupdesc, 3, &isnull)));
        coupon = DatumGetInt32(SPI_getbinval(tuple, tupdesc, 4, &isnull));
        issue_date = TDate_from_DateADT(DatumGetDateADT(SPI_getbinval(tuple, tupdesc, 5, &isnull)));
        factor = DatumGetFloat8(SPI_getbinval(tuple, tupdesc, 6, &isnull));
        version = DatumGetInt16(SPI_getbinval(tuple, tupdesc, 7, &isnull));
        cumulativeloss = DatumGetFloat8(SPI_getbinval(tuple, tupdesc, 8, &isnull));
    }
    char* yc_query
    SPI_finish();
    pfree(index);
    pfree(tenor);
    PG_RETURN_NULL();
}