#include "Base64.h"

namespace vf {

std::string base64Encode(const std::vector<uint8_t>& bytes) {
    static const char* table =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    std::string out;
    out.reserve((bytes.size() + 2) / 3 * 4);
    std::size_t i = 0;
    for (; i + 2 < bytes.size(); i += 3) {
        uint32_t n = (bytes[i] << 16) | (bytes[i + 1] << 8) | bytes[i + 2];
        out.push_back(table[(n >> 18) & 63]);
        out.push_back(table[(n >> 12) & 63]);
        out.push_back(table[(n >> 6) & 63]);
        out.push_back(table[n & 63]);
    }
    if (i < bytes.size()) {
        uint32_t n = bytes[i] << 16;
        bool two = (i + 1 < bytes.size());
        if (two) n |= bytes[i + 1] << 8;
        out.push_back(table[(n >> 18) & 63]);
        out.push_back(table[(n >> 12) & 63]);
        out.push_back(two ? table[(n >> 6) & 63] : '=');
        out.push_back('=');
    }
    return out;
}

std::vector<uint8_t> base64Decode(const std::string& text) {
    auto value = [](char c) -> int {
        if (c >= 'A' && c <= 'Z') return c - 'A';
        if (c >= 'a' && c <= 'z') return c - 'a' + 26;
        if (c >= '0' && c <= '9') return c - '0' + 52;
        if (c == '+') return 62;
        if (c == '/') return 63;
        return -1;
    };
    std::vector<uint8_t> out;
    int buffer = 0, bits = 0;
    for (char c : text) {
        if (c == '=') break;
        int v = value(c);
        if (v < 0) continue;
        buffer = (buffer << 6) | v;
        bits += 6;
        if (bits >= 8) {
            bits -= 8;
            out.push_back(static_cast<uint8_t>((buffer >> bits) & 0xff));
        }
    }
    return out;
}

} // namespace vf