#include <stdbool.h>
#include <stdlib.h>

#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "nlr.h"
#include "obj.h"
#include "parsenumbase.h"
#include "parsenum.h"

#if MICROPY_ENABLE_FLOAT
#include <math.h>
#endif

#if defined(UNIX)

#include <ctype.h>
#include <errno.h>

mp_obj_t mp_parse_num_integer(const char *restrict str, uint len, int base) {
    // TODO at the moment we ignore len; we should honour it!
    // TODO detect integer overflow and return bignum

    int c, neg = 0;
    const char *p = str;
    char *num;
    long found;

    // check radix base
    if ((base != 0 && base < 2) || base > 36) {
        nlr_jump(mp_obj_new_exception_msg(&mp_type_ValueError, "ValueError: int() arg 2 must be >=2 and <= 36"));
    }
    // skip surrounded whitespace
    while (isspace((c = *(p++))));
    if (c == 0) {
        goto value_error;
    }
    // preced sign
    if (c == '+' || c == '-') {
        neg = - (c == '-');
    } else {
        p--;
    }

    len -= p - str;
    int skip = mp_parse_num_base(p, len, &base);
    p += skip;
    len -= skip;

    errno = 0;
    found = strtol(p, &num, base);
    if (errno) {
        goto value_error;
    } else if (found && *(num) == 0) {
        goto done;
    } else if (found || num != p) {
        goto check_tail_space;
    } else {
        goto value_error;
    }

check_tail_space:
    if (*(num) != 0) {
        while (isspace((c = *(num++))));
        if (c != 0) {
            goto value_error;
        }
    }

done:
    return MP_OBJ_NEW_SMALL_INT((found ^ neg) - neg);

value_error:
    nlr_jump(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "invalid literal for int() with base %d: '%s'", base, str));
}

#else /* defined(UNIX) */

mp_obj_t mp_parse_num_integer(const char *restrict str, uint len, int base) {
    // TODO port strtol to stm
    return MP_OBJ_NEW_SMALL_INT(0);
}

#endif /* defined(UNIX) */

#define PARSE_DEC_IN_INTG (1)
#define PARSE_DEC_IN_FRAC (2)
#define PARSE_DEC_IN_EXP  (3)

mp_obj_t mp_parse_num_decimal(const char *str, uint len, bool allow_imag) {
#if MICROPY_ENABLE_FLOAT
    const char *top = str + len;
    mp_float_t dec_val = 0;
    bool dec_neg = false;
    bool imag = false;

    // skip leading space
    for (; str < top && isspace(*str); str++) {
    }

    // get optional sign
    if (str < top) {
        if (*str == '+') {
            str++;
        } else if (*str == '-') {
            str++;
            dec_neg = true;
        }
    }

    // determine what the string is
    if (str < top && (str[0] | 0x20) == 'i') {
        // string starts with 'i', should be 'inf' or 'infinity' (case insensitive)
        if (str + 2 < top && (str[1] | 0x20) == 'n' && (str[2] | 0x20) == 'f') {
            // inf
            str += 3;
            dec_val = INFINITY;
            if (str + 4 < top && (str[0] | 0x20) == 'i' && (str[1] | 0x20) == 'n' && (str[2] | 0x20) == 'i' && (str[3] | 0x20) == 't' && (str[4] | 0x20) == 'y') {
                // infinity
                str += 5;
            }
        }
    } else if (str < top && (str[0] | 0x20) == 'n') {
        // string starts with 'n', should be 'nan' (case insensitive)
        if (str + 2 < top && (str[1] | 0x20) == 'a' && (str[2] | 0x20) == 'n') {
            // NaN
            str += 3;
            dec_val = MICROPY_FLOAT_C_FUN(nan)("");
        }
    } else {
        // parse the digits
        int in = PARSE_DEC_IN_INTG;
        bool exp_neg = false;
        int exp_val = 0;
        int exp_extra = 0;
        for (; str < top; str++) {
            int dig = *str;
            if ('0' <= dig && dig <= '9') {
                dig -= '0';
                if (in == PARSE_DEC_IN_EXP) {
                    exp_val = 10 * exp_val + dig;
                } else {
                    dec_val = 10 * dec_val + dig;
                    if (in == PARSE_DEC_IN_FRAC) {
                        exp_extra -= 1;
                    }
                }
            } else if (in == PARSE_DEC_IN_INTG && dig == '.') {
                in = PARSE_DEC_IN_FRAC;
            } else if (in != PARSE_DEC_IN_EXP && ((dig | 0x20) == 'e')) {
                in = PARSE_DEC_IN_EXP;
                if (str[1] == '+') {
                    str++;
                } else if (str[1] == '-') {
                    str++;
                    exp_neg = true;
                }
            } else if (allow_imag && (dig | 0x20) == 'j') {
                str++;
                imag = true;
                break;
            } else {
                // unknown character
                break;
            }
        }

        // work out the exponent
        if (exp_neg) {
            exp_val = -exp_val;
        }
        exp_val += exp_extra;

        // apply the exponent
        for (; exp_val > 0; exp_val--) {
            dec_val *= 10;
        }
        for (; exp_val < 0; exp_val++) {
            dec_val *= 0.1;
        }
    }

    // negate value if needed
    if (dec_neg) {
        dec_val = -dec_val;
    }

    // skip trailing space
    for (; str < top && isspace(*str); str++) {
    }

    // check we reached the end of the string
    if (str != top) {
        nlr_jump(mp_obj_new_exception_msg(&mp_type_SyntaxError, "invalid syntax for number"));
    }

    // return the object
    if (imag) {
        return mp_obj_new_complex(0, dec_val);
    } else {
        return mp_obj_new_float(dec_val);
    }

#else
    nlr_jump(mp_obj_new_exception_msg(&mp_type_SyntaxError, "decimal numbers not supported"));
#endif
}