#include "common/string_utils.hpp"
#include <cstdlib>
#include <openssl/bio.h>
#include <openssl/evp.h>
#include <openssl/buffer.h>

namespace smartbotic::common {

std::string StringUtils::trim(std::string_view str) {
    return trimRight(trimLeft(str));
}

std::string StringUtils::trimLeft(std::string_view str) {
    auto it = std::find_if(str.begin(), str.end(),
        [](unsigned char c) { return !std::isspace(c); });
    return std::string(it, str.end());
}

std::string StringUtils::trimRight(std::string_view str) {
    auto it = std::find_if(str.rbegin(), str.rend(),
        [](unsigned char c) { return !std::isspace(c); });
    return std::string(str.begin(), it.base());
}

std::string StringUtils::toLower(std::string_view str) {
    std::string result(str);
    std::transform(result.begin(), result.end(), result.begin(),
        [](unsigned char c) { return std::tolower(c); });
    return result;
}

std::string StringUtils::toUpper(std::string_view str) {
    std::string result(str);
    std::transform(result.begin(), result.end(), result.begin(),
        [](unsigned char c) { return std::toupper(c); });
    return result;
}

std::vector<std::string> StringUtils::split(std::string_view str, char delimiter) {
    std::vector<std::string> result;
    std::string current;
    for (char c : str) {
        if (c == delimiter) {
            result.push_back(std::move(current));
            current.clear();
        } else {
            current += c;
        }
    }
    result.push_back(std::move(current));
    return result;
}

std::vector<std::string> StringUtils::split(std::string_view str, std::string_view delimiter) {
    std::vector<std::string> result;
    size_t start = 0;
    size_t end = str.find(delimiter);

    while (end != std::string_view::npos) {
        result.emplace_back(str.substr(start, end - start));
        start = end + delimiter.length();
        end = str.find(delimiter, start);
    }
    result.emplace_back(str.substr(start));
    return result;
}

std::string StringUtils::join(const std::vector<std::string>& parts, std::string_view delimiter) {
    if (parts.empty()) return "";

    std::ostringstream ss;
    ss << parts[0];
    for (size_t i = 1; i < parts.size(); ++i) {
        ss << delimiter << parts[i];
    }
    return ss.str();
}

bool StringUtils::startsWith(std::string_view str, std::string_view prefix) {
    return str.size() >= prefix.size() && str.substr(0, prefix.size()) == prefix;
}

bool StringUtils::endsWith(std::string_view str, std::string_view suffix) {
    return str.size() >= suffix.size() &&
           str.substr(str.size() - suffix.size()) == suffix;
}

bool StringUtils::contains(std::string_view str, std::string_view substr) {
    return str.find(substr) != std::string_view::npos;
}

std::string StringUtils::replace(std::string_view str, std::string_view from, std::string_view to) {
    std::string result(str);
    size_t pos = result.find(from);
    if (pos != std::string::npos) {
        result.replace(pos, from.length(), to);
    }
    return result;
}

std::string StringUtils::replaceAll(std::string_view str, std::string_view from, std::string_view to) {
    std::string result(str);
    size_t pos = 0;
    while ((pos = result.find(from, pos)) != std::string::npos) {
        result.replace(pos, from.length(), to);
        pos += to.length();
    }
    return result;
}

std::string StringUtils::interpolate(std::string_view tmpl,
                                     const std::unordered_map<std::string, std::string>& vars) {
    std::string result(tmpl);
    std::regex pattern(R"(\$\{([^}]+)\})");

    std::string output;
    auto it = std::sregex_iterator(result.begin(), result.end(), pattern);
    auto end = std::sregex_iterator();
    size_t lastPos = 0;

    for (; it != end; ++it) {
        output += result.substr(lastPos, it->position() - lastPos);
        std::string varName = (*it)[1].str();
        auto found = vars.find(varName);
        if (found != vars.end()) {
            output += found->second;
        } else {
            output += it->str(); // Keep original if not found
        }
        lastPos = it->position() + it->length();
    }
    output += result.substr(lastPos);

    return output;
}

std::string StringUtils::expandEnvVars(std::string_view str) {
    std::string result(str);
    std::regex pattern(R"(\$\{([^:}]+)(?::([^}]*))?\})");

    std::string output;
    auto it = std::sregex_iterator(result.begin(), result.end(), pattern);
    auto end = std::sregex_iterator();
    size_t lastPos = 0;

    for (; it != end; ++it) {
        output += result.substr(lastPos, it->position() - lastPos);
        std::string varName = (*it)[1].str();
        std::string defaultValue = (*it)[2].matched ? (*it)[2].str() : "";

        const char* envValue = std::getenv(varName.c_str());
        if (envValue) {
            output += envValue;
        } else {
            output += defaultValue;
        }
        lastPos = it->position() + it->length();
    }
    output += result.substr(lastPos);

    return output;
}

std::string StringUtils::urlEncode(std::string_view str) {
    std::ostringstream escaped;
    escaped.fill('0');
    escaped << std::hex;

    for (char c : str) {
        if (std::isalnum(static_cast<unsigned char>(c)) ||
            c == '-' || c == '_' || c == '.' || c == '~') {
            escaped << c;
        } else {
            escaped << std::uppercase;
            escaped << '%' << std::setw(2) << int(static_cast<unsigned char>(c));
            escaped << std::nouppercase;
        }
    }

    return escaped.str();
}

std::string StringUtils::urlDecode(std::string_view str) {
    std::string result;
    result.reserve(str.size());

    for (size_t i = 0; i < str.size(); ++i) {
        if (str[i] == '%' && i + 2 < str.size()) {
            int hex = std::stoi(std::string(str.substr(i + 1, 2)), nullptr, 16);
            result += static_cast<char>(hex);
            i += 2;
        } else if (str[i] == '+') {
            result += ' ';
        } else {
            result += str[i];
        }
    }

    return result;
}

std::string StringUtils::base64Encode(std::string_view data) {
    BIO* b64 = BIO_new(BIO_f_base64());
    BIO* bio = BIO_new(BIO_s_mem());
    bio = BIO_push(b64, bio);

    BIO_set_flags(bio, BIO_FLAGS_BASE64_NO_NL);
    BIO_write(bio, data.data(), static_cast<int>(data.size()));
    BIO_flush(bio);

    BUF_MEM* bufferPtr;
    BIO_get_mem_ptr(bio, &bufferPtr);

    std::string result(bufferPtr->data, bufferPtr->length);
    BIO_free_all(bio);

    return result;
}

std::string StringUtils::base64Decode(std::string_view encoded) {
    BIO* b64 = BIO_new(BIO_f_base64());
    BIO* bio = BIO_new_mem_buf(encoded.data(), static_cast<int>(encoded.size()));
    bio = BIO_push(b64, bio);

    BIO_set_flags(bio, BIO_FLAGS_BASE64_NO_NL);

    std::string result(encoded.size(), '\0');
    int length = BIO_read(bio, result.data(), static_cast<int>(result.size()));

    BIO_free_all(bio);

    if (length > 0) {
        result.resize(length);
    } else {
        result.clear();
    }

    return result;
}

std::string StringUtils::hexEncode(const std::vector<uint8_t>& data) {
    static const char hex[] = "0123456789abcdef";
    std::string result;
    result.reserve(data.size() * 2);

    for (uint8_t byte : data) {
        result += hex[byte >> 4];
        result += hex[byte & 0x0f];
    }

    return result;
}

std::vector<uint8_t> StringUtils::hexDecode(std::string_view hex) {
    std::vector<uint8_t> result;
    result.reserve(hex.size() / 2);

    for (size_t i = 0; i + 1 < hex.size(); i += 2) {
        uint8_t byte = static_cast<uint8_t>(std::stoi(std::string(hex.substr(i, 2)), nullptr, 16));
        result.push_back(byte);
    }

    return result;
}

} // namespace smartbotic::common