#include "libft.h"

/**
 * Parses a string of superscript digits (e.g., "²³⁴") into a long long.
 * Returns the integer value, or LLONG_MAX/LLONG_MIN on overflow.
 */
long long ft_atoll_superscript(const char *str)
{
    long long nbr = 0;
    int i = 0;
    int negatif = 1;
    int superscript_size;

    // Skip leading whitespace
    while (ft_isspace(str[i]))
        i++;

    // Handle optional sign
    if (str[i] == '-')
        negatif = -1;
    if (str[i] == '+' || str[i] == '-')
        i++;

    // Parse superscript digits
    while (1)
    {
        if (!ft_isdigit_superscript(&str[i], &superscript_size))
            break; // Not a superscript digit

        // Extract the digit value (0-9) from the superscript character
        int digit;
        if (superscript_size == 2)
        {
            // ¹ (U+00B9), ² (U+00B2), or ³ (U+00B3)
            if ((uint8_t)str[i + 1] == 0xB9)
                digit = 1;
            else if ((uint8_t)str[i + 1] == 0xB2)
                digit = 2;
            else if ((uint8_t)str[i + 1] == 0xB3)
                digit = 3;
            else
                break; // Invalid, should not happen
        }
        else if (superscript_size == 3)
        {
            // ⁰ (U+2070) to ⁹ (U+2079)
            digit = (uint8_t)str[i + 2] - 0xB0; // 0xB0 → 0, 0xB1 → 1, ..., 0xB9 → 9
        }
        else
        {
            break; // Invalid, should not happen
        }

        // Check for overflow
        if (nbr > LLONG_MAX / 10 ||
            (nbr == LLONG_MAX / 10 && digit > LLONG_MAX % 10))
        {
            return (negatif > 0) ? LLONG_MAX : LLONG_MIN;
        }

        nbr = nbr * 10 + digit;
        i += superscript_size; // Skip the entire UTF-8 character
    }

    return (nbr * negatif);
}