#include "core/utils/ArrayString.hpp"

#include "core/utils/Error.hpp"

static c32 read(const char*& s) {
    if(*s == '\0') {
        return 0;
    }
    return static_cast<c32>(*(s++));
}

Core::Error Core::readUnicode(c32& u, const char*& s) {
    u = read(s);
    if((u & 0x80) == 0) {
        return Error::NONE;
    }
    if((u & 0xE0) == 0xC0) {
        c32 u2 = read(s);
        if(u2 == 0) {
            return Error::INVALID_CHAR;
        }
        u = ((u & 0x1F) << 6) | (u2 & 0x3F);
        return Error::NONE;
    } else if((u & 0xF0) == 0xE0) {
        c32 u2 = read(s);
        c32 u3 = read(s);
        if(u2 == 0 || u3 == 0) {
            return Error::INVALID_CHAR;
        }
        u = ((u & 0xF) << 12) | ((u2 & 0x3F) << 6) | (u3 & 0x3F);
        return Error::NONE;
    } else if((u & 0xF8) == 0xF0) {
        c32 u2 = read(s);
        c32 u3 = read(s);
        c32 u4 = read(s);
        if(u2 == 0 || u3 == 0 || u4 == 0) {
            return Error::INVALID_CHAR;
        }
        u = ((u & 0x07) << 18) | ((u2 & 0x3F) << 12) | ((u3 & 0x3F) << 6) |
            (u4 & 0x3F);
        return Error::NONE;
    }
    return Error::INVALID_CHAR;
}