#include "bstl/string.hpp"

#include <sstream>
#include <stdexcept>

namespace bstl {

String::String() : data_("") {}

String::String(const std::string& str) : data_(str) {}

String::String(const char* str) : data_(str == nullptr ? "" : str) {}

std::string String::str() const {
    return data_;
}

const char* String::c_str() const {
    return data_.c_str();
}

size_t String::length() const {
    return data_.length();
}

size_t String::size() const {
    return data_.size();
}

bool String::empty() const {
    return data_.empty();
}

char String::at(size_t pos) const {
    if (pos >= data_.size()) {
        throw std::out_of_range("String::at: index out of range");
    }
    return data_[pos];
}

char String::operator[](size_t pos) const {
    return data_[pos];
}

char& String::operator[](size_t pos) {
    return data_[pos];
}

std::vector<String> String::split(const String& delimiter) const {
    std::vector<String> result;
    
    if (data_.empty()) {
        return result;
    }

    if (delimiter.empty()) {
        result.push_back(*this);
        return result;
    }

    size_t start = 0;
    size_t pos = 0;
    
    while ((pos = data_.find(delimiter.data_, start)) != std::string::npos) {
        result.push_back(String(data_.substr(start, pos - start)));
        start = pos + delimiter.size();
    }
    
    result.push_back(String(data_.substr(start)));
    return result;
}

String String::join(const std::vector<String>& parts, const String& delimiter) {
    if (parts.empty()) {
        return String("");
    }
    
    std::string result = parts[0].str();
    for (size_t i = 1; i < parts.size(); i++) {
        result += delimiter.str() + parts[i].str();
    }
    return String(result);
}

String String::replace(const String& oldStr, const String& newStr, int count) const {
    if (oldStr.empty()) {
        return *this;
    }

    std::string result = data_;
    size_t pos = 0;
    int replaced = 0;

    while ((pos = result.find(oldStr.data_, pos)) != std::string::npos && (count < 0 || replaced < count)) {
        result.replace(pos, oldStr.size(), newStr.str());
        pos += newStr.size();
        replaced++;
    }

    return String(result);
}

String String::upper() const {
    std::string result = data_;
    std::transform(result.begin(), result.end(), result.begin(),
                   [](unsigned char c) { return std::toupper(c); });
    return String(result);
}

String String::lower() const {
    std::string result = data_;
    std::transform(result.begin(), result.end(), result.begin(),
                   [](unsigned char c) { return std::tolower(c); });
    return String(result);
}

String String::capitalize() const {
    if (data_.empty()) {
        return *this;
    }
    std::string result = data_;
    result[0] = std::toupper(static_cast<unsigned char>(result[0]));
    for (size_t i = 1; i < result.size(); i++) {
        result[i] = std::tolower(static_cast<unsigned char>(result[i]));
    }
    return String(result);
}

String String::title() const {
    std::string result = data_;
    bool newWord = true;
    for (size_t i = 0; i < result.size(); i++) {
        if (std::isspace(static_cast<unsigned char>(result[i]))) {
            newWord = true;
        } else {
            if (newWord) {
                result[i] = std::toupper(static_cast<unsigned char>(result[i]));
                newWord = false;
            } else {
                result[i] = std::tolower(static_cast<unsigned char>(result[i]));
            }
        }
    }
    return String(result);
}

bool String::startswith(const String& prefix) const {
    if (prefix.size() > data_.size()) {
        return false;
    }
    return data_.compare(0, prefix.size(), prefix.data_) == 0;
}

bool String::endswith(const String& suffix) const {
    if (suffix.size() > data_.size()) {
        return false;
    }
    return data_.compare(data_.size() - suffix.size(), suffix.size(), suffix.data_) == 0;
}

bool String::contains(const String& substring) const {
    return data_.find(substring.data_) != std::string::npos;
}

bool String::isdigit() const {
    if (data_.empty()) return false;
    for (unsigned char c : data_) {
        if (!std::isdigit(c)) return false;
    }
    return true;
}

bool String::isalpha() const {
    if (data_.empty()) return false;
    for (unsigned char c : data_) {
        if (!std::isalpha(c)) return false;
    }
    return true;
}

bool String::isalnum() const {
    if (data_.empty()) return false;
    for (unsigned char c : data_) {
        if (!std::isalnum(c)) return false;
    }
    return true;
}

bool String::isspace() const {
    if (data_.empty()) return false;
    for (unsigned char c : data_) {
        if (!std::isspace(c)) return false;
    }
    return true;
}

bool String::isupper() const {
    if (data_.empty()) return false;
    for (unsigned char c : data_) {
        if (std::isalpha(c) && !std::isupper(c)) {
            return false;
        }
    }
    return true;
}

bool String::islower() const {
    if (data_.empty()) return false;
    for (unsigned char c : data_) {
        if (std::isalpha(c) && !std::islower(c)) {
            return false;
        }
    }
    return true;
}

int String::find(const String& substring, size_t start) const {
    size_t pos = data_.find(substring.data_, start);
    return pos == std::string::npos ? -1 : static_cast<int>(pos);
}

int String::rfind(const String& substring) const {
    size_t pos = data_.rfind(substring.data_);
    return pos == std::string::npos ? -1 : static_cast<int>(pos);
}

int String::count(const String& substring) const {
    if (substring.empty()) return 0;
    int count = 0;
    size_t pos = 0;
    while ((pos = data_.find(substring.data_, pos)) != std::string::npos) {
        count++;
        pos += substring.size();
    }
    return count;
}

String String::strip() const {
    size_t start = 0;
    size_t end = data_.size();

    while (start < end && std::isspace(static_cast<unsigned char>(data_[start]))) {
        start++;
    }
    while (end > start && std::isspace(static_cast<unsigned char>(data_[end - 1]))) {
        end--;
    }

    return String(data_.substr(start, end - start));
}

String String::lstrip() const {
    size_t start = 0;
    while (start < data_.size() && std::isspace(static_cast<unsigned char>(data_[start]))) {
        start++;
    }
    return String(data_.substr(start));
}

String String::rstrip() const {
    size_t end = data_.size();
    while (end > 0 && std::isspace(static_cast<unsigned char>(data_[end - 1]))) {
        end--;
    }
    return String(data_.substr(0, end));
}

String String::strip(const String& chars) const {
    size_t start = 0;
    size_t end = data_.size();

    while (start < end && chars.data_.find(data_[start]) != std::string::npos) {
        start++;
    }
    while (end > start && chars.data_.find(data_[end - 1]) != std::string::npos) {
        end--;
    }

    return String(data_.substr(start, end - start));
}

String String::ljust(size_t width, char fillchar) const {
    if (data_.size() >= width) {
        return *this;
    }
    std::string result = data_;
    result.append(width - data_.size(), fillchar);
    return String(result);
}

String String::rjust(size_t width, char fillchar) const {
    if (data_.size() >= width) {
        return *this;
    }
    std::string result(width - data_.size(), fillchar);
    result.append(data_);
    return String(result);
}

String String::center(size_t width, char fillchar) const {
    if (data_.size() >= width) {
        return *this;
    }
    size_t totalPad = width - data_.size();
    size_t leftPad = totalPad / 2;
    size_t rightPad = totalPad - leftPad;
    std::string result(leftPad, fillchar);
    result.append(data_);
    result.append(rightPad, fillchar);
    return String(result);
}

int String::toInt() const {
    return std::stoi(data_);
}

long long String::toLongLong() const {
    return std::stoll(data_);
}

double String::toDouble() const {
    return std::stod(data_);
}

String String::operator+(const String& other) const {
    return String(data_ + other.data_);
}

String String::operator+(const char* str) const {
    return String(data_ + (str == nullptr ? "" : str));
}

String& String::operator+=(const String& other) {
    data_ += other.data_;
    return *this;
}

bool String::operator==(const String& other) const {
    return data_ == other.data_;
}

bool String::operator!=(const String& other) const {
    return data_ != other.data_;
}

bool String::operator<(const String& other) const {
    return data_ < other.data_;
}

bool String::operator>(const String& other) const {
    return data_ > other.data_;
}

bool String::operator<=(const String& other) const {
    return data_ <= other.data_;
}

bool String::operator>=(const String& other) const {
    return data_ >= other.data_;
}

} // namespace bstl