/*
* Copyright (c) 2018 Calvin Rose
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/

#include <dst/dst.h>
#include <math.h>

/* Get a random number */
int dst_rand(DstArgs args) {
    DST_FIXARITY(args, 0);
    double r = (rand() % RAND_MAX) / ((double) RAND_MAX);
    DST_RETURN_REAL(args, r);
}

/* Seed the random number generator */
int dst_srand(DstArgs args) {
    int32_t x = 0;
    DST_FIXARITY(args, 1);
    DST_ARG_INTEGER(x, args, 0);
    srand((unsigned) x);
    return 0;
}

/* Convert a number to an integer */
int dst_int(DstArgs args) {
    DST_FIXARITY(args, 1);
    switch (dst_type(args.v[0])) {
        default:
            DST_THROW(args, "could not convert to integer");
        case DST_REAL:
            *args.ret = dst_wrap_integer((int32_t) dst_unwrap_real(args.v[0]));
            break;
        case DST_INTEGER:
            *args.ret = args.v[0];
            break;
    }
    return 0;
}

/* Convert a number to a real number */
int dst_real(DstArgs args) {
    DST_FIXARITY(args, 1);
    switch (dst_type(args.v[0])) {
        default:
            DST_THROW(args, "could not convert to real");
        case DST_REAL:
            *args.ret = args.v[0];
            break;
        case DST_INTEGER:
            *args.ret = dst_wrap_real((double) dst_unwrap_integer(args.v[0]));
            break;
    }
    return 0;
}

int dst_remainder(DstArgs args) {
    DST_FIXARITY(args, 2);
    if (dst_checktype(args.v[0], DST_INTEGER) &&
            dst_checktype(args.v[1], DST_INTEGER)) {
        int32_t x, y;
        x = dst_unwrap_integer(args.v[0]);
        y = dst_unwrap_integer(args.v[1]);
        DST_RETURN_INTEGER(args, x % y);
    } else {
        double x, y;
        DST_ARG_NUMBER(x, args, 0);
        DST_ARG_NUMBER(y, args, 1);
        DST_RETURN_REAL(args, fmod(x, y));
    }
}

#define DST_DEFINE_MATHOP(name, fop)\
int dst_##name(DstArgs args) {\
    double x;\
    DST_FIXARITY(args, 1);\
    DST_ARG_NUMBER(x, args, 0);\
    DST_RETURN_REAL(args, fop(x));\
}

DST_DEFINE_MATHOP(acos, acos)
DST_DEFINE_MATHOP(asin, asin)
DST_DEFINE_MATHOP(atan, atan)
DST_DEFINE_MATHOP(cos, cos)
DST_DEFINE_MATHOP(cosh, cosh)
DST_DEFINE_MATHOP(sin, sin)
DST_DEFINE_MATHOP(sinh, sinh)
DST_DEFINE_MATHOP(tan, tan)
DST_DEFINE_MATHOP(tanh, tanh)
DST_DEFINE_MATHOP(exp, exp)
DST_DEFINE_MATHOP(log, log)
DST_DEFINE_MATHOP(log10, log10)
DST_DEFINE_MATHOP(sqrt, sqrt)
DST_DEFINE_MATHOP(ceil, ceil)
DST_DEFINE_MATHOP(fabs, fabs)
DST_DEFINE_MATHOP(floor, floor)

#define DST_DEFINE_MATH2OP(name, fop)\
int dst_##name(DstArgs args) {\
    double lhs, rhs;\
    DST_FIXARITY(args, 2);\
    DST_ARG_NUMBER(lhs, args, 0);\
    DST_ARG_NUMBER(rhs, args, 1);\
    DST_RETURN_REAL(args, fop(lhs, rhs));\
}\

DST_DEFINE_MATH2OP(atan2, atan2)
DST_DEFINE_MATH2OP(pow, pow)

static int dst_not(DstArgs args) {
    DST_FIXARITY(args, 1);
    DST_RETURN_BOOLEAN(args, !dst_truthy(args.v[0]));
}

static const DstReg cfuns[] = {
    {"%", dst_remainder},
    {"not", dst_not},
    {"int", dst_int},
    {"real", dst_real},
    {"math.random", dst_rand},
    {"math.seedrandom", dst_srand},
    {"math.cos", dst_cos},
    {"math.sin", dst_sin},
    {"math.tan", dst_tan},
    {"math.acos", dst_acos},
    {"math.asin", dst_asin},
    {"math.atan", dst_atan},
    {"math.exp", dst_exp},
    {"math.log", dst_log},
    {"math.log10", dst_log10},
    {"math.sqrt", dst_sqrt},
    {"math.floor", dst_floor},
    {"math.ceil", dst_ceil},
    {"math.pow", dst_pow},
    {NULL, NULL}
};

/* Module entry point */
int dst_lib_math(DstArgs args) {
    DstTable *env = dst_env(args);
    dst_cfuns(env, NULL, cfuns);

    dst_def(env, "math.pi", dst_wrap_real(3.1415926535897931));
    dst_def(env, "math.e", dst_wrap_real(2.7182818284590451));
    dst_def(env, "math.inf", dst_wrap_real(INFINITY));
    return 0;
}