#include "utils.hpp"
#include "httplib.hpp"
#include <nlohmann/json.hpp>

#include <memory>
#include <iostream>
#include <string>
#include <fstream>
#include <cstdlib>
#include <vector>
#include <algorithm>
#include <filesystem>
#include <regex>
#include <random>
#include <sys/ioctl.h>
#include <unistd.h>
#include <cctype>
#include <sstream>

namespace dropshell {

std::string magic_string() {
    return "-_-";
}

bool has_magic_string(std::string name)
{
    return name.find(magic_string()) != std::string::npos;
}


void maketitle(const std::string& title, sColour colour) {
    colourstream(colour) << std::string(title.length() + 4, '-') << std::endl;
    colourstream(colour) << "| " << title << " |" << std::endl;
    colourstream(colour) << std::string(title.length() + 4, '-') << std::endl;
}

bool replace_line_in_file(const std::string& file_path, const std::string& search_string, const std::string& replacement_line) {
    std::ifstream input_file(file_path);
    std::vector<std::string> file_lines;
    std::string line;

    if (!input_file.is_open()) {
        error << "Unable to open file: " << file_path << std::endl;
        return false;
    }

    while (std::getline(input_file, line)) {
        if (line.find(search_string) != std::string::npos)
            file_lines.push_back(replacement_line);
            else
                file_lines.push_back(line);
        }
    input_file.close();
        
    std::ofstream output_file(file_path);
    if (!output_file.is_open())
    {
        error << "Unable to open file: " << file_path << std::endl;
        return false;
    }
    for (const auto& modified_line : file_lines)
        output_file << modified_line << "\n";
    output_file.close();
    return true;
}

std::string trim(std::string str) {
    // Trim leading whitespace
    str.erase(str.begin(), std::find_if(str.begin(), str.end(), [](unsigned char ch) {
        return !std::isspace(ch);
    }));

    // Trim trailing whitespace
    str.erase(std::find_if(str.rbegin(), str.rend(), [](unsigned char ch) {
        return !std::isspace(ch);
    }).base(), str.end());

    return str;
}

std::string dequote(std::string str)
{
    if (str.length() < 2)
        return str;
    if (str.front() == '"' && str.back() == '"') {
        return str.substr(1, str.length() - 2);
    }
    return str;
}

std::string quote(std::string str)
{
    return "\""+str+"\"";
}

std::string halfquote(std::string str)
{
    return "'" + str + "'";
}

std::string escapequotes(std::string str)
{
    return std::regex_replace(str, std::regex("\""), "\\\"");
}

std::string multi2string(std::vector<std::string> values)
{
    std::string result;
    for (const auto& value : values) {
        // remove any " contained in the string value, if present
        result += dequote(trim(value)) + ",";
    }
    if (!result.empty()) 
        result.pop_back(); // Remove the last comma
    
    return result;
}

std::vector<std::string> string2multi(std::string values)
{
    std::vector<std::string> result;

    values = dequote(trim(values));

    // Return values separated by commas, but ignore commas within quotes
    bool inside_quotes = false;
    std::string current_item;
    
    for (char c : values) {
        if (c == '"') {
            inside_quotes = !inside_quotes;
        } else if (c == ',' && !inside_quotes) {
            if (!current_item.empty()) {
                std::string final = dequote(trim(current_item));
                if (!final.empty()) 
                    result.push_back(final);
                current_item.clear();
            }
        } else {
            current_item += c;
        }
    }
    
    // Add the last item if not empty
    if (!current_item.empty()) {
        std::string final = dequote(trim(current_item));
        if (!final.empty()) 
            result.push_back(final);
    }
    
    return result;
}

int str2int(const std::string &str)
{
    try {
        return std::stoi(str);
    } catch (const std::exception& e) {
        error << "Invalid integer string: [" << str << "]" << std::endl;
        return 0;
    }
}


void recursive_copy(const std::string & source, const std::string & destination) {
    try {
        if (std::filesystem::is_directory(source)) {
            if (!std::filesystem::exists(destination)) {
                std::filesystem::create_directory(destination);
            }
            for (const auto& entry : std::filesystem::directory_iterator(source)) {
                recursive_copy(entry.path(), destination / entry.path().filename());
            }
        } else if (std::filesystem::is_regular_file(source)) {
            std::filesystem::copy(source, destination, std::filesystem::copy_options::overwrite_existing);
        }
    } catch (const std::filesystem::filesystem_error& ex) {
        std::cerr << "Error copying " << source << " to " << destination << ": " << ex.what() << std::endl;
    }
}

void ensure_directories_exist(std::vector<std::string> directories)
{
    for (const auto& directory : directories) {
        if (!std::filesystem::exists(directory)) {
            std::filesystem::create_directories(directory);
        }
    }
}


//https://www.geeksforgeeks.org/kmp-algorithm-for-pattern-searching/
void constructLps(const std::string &pat, std::vector<int> &lps) {

    // len stores the length of longest prefix which
    // is also a suffix for the previous index
    int len = 0;

    // lps[0] is always 0
    lps[0] = 0;

    int i = 1;
    while (i < pat.length()) {

        // If characters match, increment the size of lps
        if (pat[i] == pat[len]) {
            len++;
            lps[i] = len;
            i++;
        }

        // If there is a mismatch
        else {
            if (len != 0) {

                // Update len to the previous lps value
                // to avoid reduntant comparisons
                len = lps[len - 1];
            }
            else {

                // If no matching prefix found, set lps[i] to 0
                lps[i] = 0;
                i++;
            }
        }
    }
}

std::vector<int> search(const std::string &pat, const std::string &txt) {
    int n = txt.length();
    int m = pat.length();

    std::vector<int> lps(m);
    std::vector<int> res;

    constructLps(pat, lps);

    // Pointers i and j, for traversing
    // the text and pattern
    int i = 0;
    int j = 0;

    while (i < n) {

        // If characters match, move both pointers forward
        if (txt[i] == pat[j]) {
            i++;
            j++;

            // If the entire pattern is matched
            // store the start index in result
            if (j == m) {
                res.push_back(i - j);

                // Use LPS of previous index to
                // skip unnecessary comparisons
                j = lps[j - 1];
            }
        }

        // If there is a mismatch
        else {

            // Use lps value of previous index
            // to avoid redundant comparisons
            if (j != 0)
                j = lps[j - 1];
            else
                i++;
        }
    }
    return res;
}

int count_substring(const std::string &substring, const std::string &text) {
    std::vector<int> positions = search(substring, text);
    return positions.size();
}

std::vector<std::string> split(const std::string& str, const std::string& delimiter) {
    std::vector<std::string> tokens;
    size_t start = 0;
    size_t end = 0;
    
    while ((end = str.find(delimiter, start)) != std::string::npos) {
        tokens.push_back(str.substr(start, end - start));
        start = end + delimiter.length();
    }
    
    // Add the last token
    tokens.push_back(str.substr(start));
    
    return tokens;
}

std::string random_alphanumeric_string(int length)
{
    static std::mt19937 generator(std::random_device{}());
    static const std::string chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    std::uniform_int_distribution<> distribution(0, chars.size() - 1);
    std::string random_string;
    for (int i = 0; i < length; ++i) {
        random_string += chars[distribution(generator)];
    }
    
    return random_string;
}

std::string requote(std::string str) {
    return quote(trim(dequote(trim(str))));
}


int return_die(const std::string & msg) {
    error << "Fatal error:" << std::endl;
    error << msg << std::endl;
    return 1;
}

std::string safearg(const std::vector<std::string> & args, int index)
{
    if (index<0 || index >= args.size()) return "";
    return args[index];
}

std::string safearg(int argc, char *argv[], int index)
{
    if (index<0 || index >= argc) return "";
    return argv[index];
}

std::string left_align(const std::string & str, int width) {
    if (static_cast<int>(str.size()) >= width)
        return str;
    return str + std::string(width - str.size(), ' ');
}

std::string right_align(const std::string & str, int width) {
    if (static_cast<int>(str.size()) >= width)
        return str;
    return std::string(width - str.size(), ' ') + str;
}

std::string center_align(const std::string & str, int width) {
    int pad = width - static_cast<int>(str.size());
    if (pad <= 0)
        return str;
    int pad_left = pad / 2;
    int pad_right = pad - pad_left;
    return std::string(pad_left, ' ') + str + std::string(pad_right, ' ');
}


std::string replace_with_environment_variables_like_bash(std::string str) {
    // Combined regex pattern for both ${var} and $var formats
    std::regex var_pattern("\\$(?:\\{([^}]+)\\}|([a-zA-Z0-9_]+))");
    std::string result = str;
    std::smatch match;
    
    while (std::regex_search(result, match, var_pattern)) {
        // match[1] will contain capture from ${var} format
        // match[2] will contain capture from $var format
        std::string var_name = match[1].matched ? match[1].str() : match[2].str();
        
        // Get value from system environment variables
        const char* env_value = std::getenv(var_name.c_str());
        std::string value = env_value ? env_value : "";
        
        result = result.replace(match.position(), match.length(), value);
    }

    // dequote the result
    return result;
}


std::string substitute_provided_key_value_pairs(std::string str, const ordered_env_vars& env_vars)
{
    // Combined regex pattern for both ${var} and $var formats
    std::regex var_pattern("\\$(?:\\{([^}]+)\\}|([a-zA-Z0-9_]+))");
    std::string result = str;
    std::smatch match;

    while (std::regex_search(result, match, var_pattern)) {
        // match[1] will contain capture from ${var} format
        // match[2] will contain capture from $var format
        std::string var_name = match[1].matched ? match[1].str() : match[2].str();

        // Get value from environment variables
        std::string value = get_var(env_vars, var_name);

        result = result.replace(match.position(), match.length(), value);
    }

    return result;
}

int get_console_width()
{
    struct winsize w;
    if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &w) == 0) {
        return w.ws_col;
    }
    // Fallback to a reasonable default if we can't get the width
    return 80;
}

std::string remove_return(std::string str)
{
    str.erase(std::remove(str.begin(), str.end(), '\n'), str.end());
    return str;
}

std::string get_line_wrap(std::string &src, int maxchars)
{
    if (src.empty())
        return "";

    if (src.length() <= maxchars)
    {
        std::string out = src;
        src.erase();
        return remove_return(out) + '\n';
    }

    // find last whitespace up to but not more than maxchars
    size_t grab_to=maxchars;
    size_t lastreturn = src.rfind('\n', maxchars);
    size_t lastspace = src.rfind(' ', maxchars);
    if (lastreturn != std::string::npos)
        grab_to = lastreturn;
    else if (lastspace != std::string::npos)
        grab_to = lastspace;

    std::string out = src.substr(0, grab_to);
    src = src.substr(grab_to + 1);
    return remove_return(out) + '\n';
}

std::string tolower(const std::string& str) {
    if (str.empty()) return str;
    
    std::string result;
    result.reserve(str.size());  // Pre-allocate space for efficiency
    
    for (unsigned char c : str) {
        result.push_back(std::tolower(c));
    }
    return result;
}

// Common utility function to make HTTP requests
struct HttpResult {
    bool success;
    int status;
    std::string body;
    std::string error;
};

HttpResult make_http_request(const std::string& url) {
    try {
        // Parse the URL to get host and path
        std::string host;
        std::string path;
        size_t protocol_end = url.find("://");
        if (protocol_end != std::string::npos) {
            size_t host_start = protocol_end + 3;
            size_t path_start = url.find('/', host_start);
            if (path_start != std::string::npos) {
                host = url.substr(host_start, path_start - host_start);
                path = url.substr(path_start);
            } else {
                host = url.substr(host_start);
                path = "/";
            }
        } else {
            return {false, 0, "", "Invalid URL format"};
        }

        // Create HTTP or HTTPS client based on protocol
        std::string protocol = url.substr(0, protocol_end);
        std::unique_ptr<httplib::Client> cli;
        
        if (protocol == "https") {
            // For HTTPS, include the full scheme and host
            cli = std::make_unique<httplib::Client>("https://" + host);
        } else if (protocol == "http") {
            cli = std::make_unique<httplib::Client>("http://" + host);
        } else {
            return {false, 0, "", "Unsupported protocol: " + protocol};
        }
        
        cli->set_connection_timeout(10); // 10 second timeout
        cli->set_read_timeout(30); // 30 second read timeout

        // Make GET request
        auto res = cli->Get(path);
        if (!res) {
            return {false, 0, "", "Failed to connect to server"};
        }
        if (res->status != 200) {
            return {false, res->status, "", "HTTP request failed with status " + std::to_string(res->status)};
        }

        return {true, res->status, res->body, ""};
    } catch (const std::exception& e) {
        return {false, 0, "", std::string("Exception: ") + e.what()};
    }
}

bool download_file(const std::string &url, const std::string &destination) {
    // For HTTPS URLs, use curl as it handles SSL properly in static builds
    if (url.substr(0, 8) == "https://") {
        std::string cmd = "curl -fsSL " + quote(url) + " -o " + quote(destination) + " 2>/dev/null";
        int result = system(cmd.c_str());
        if (result != 0) {
            warning << "Failed to download file from URL: " << url << std::endl;
            return false;
        }
        // Check if file was actually created
        std::ifstream check_file(destination);
        return check_file.good();
    }
    
    // For HTTP URLs, use the built-in httplib
    auto result = make_http_request(url);
    if (!result.success) {
        warning << "Failed to download file from URL: " << url << std::endl;
        return false;
    }

    try {
        std::ofstream out_file(destination, std::ios::binary);
        if (!out_file) {
            warning << "Failed to open file for writing: " << destination << std::endl;
            return false;
        }
        out_file.write(result.body.c_str(), result.body.size());
        out_file.close();
        return true;
    } catch (const std::exception& e) {
        warning << "Failed to download file from URL: " << url << std::endl;
        warning << "Exception: " << e.what() << std::endl;
        return false;
    }
}

nlohmann::json get_json_from_url(const std::string &url) {
    auto result = make_http_request(url);
    if (!result.success) {
        warning << "Failed to get JSON from URL: " << url << std::endl;
        return nlohmann::json();
    }

    try {
        return nlohmann::json::parse(result.body);
    } catch (const nlohmann::json::parse_error& e) {
        warning << "Failed to parse JSON from URL: " << url << std::endl;
        warning << "JSON: " << result.body << std::endl;
        return nlohmann::json();
    }
}

std::string get_string_from_url(const std::string &url) {
    auto result = make_http_request(url);
    if (!result.success) {
        warning << "Failed to get string from URL: " << url << std::endl;
        return std::string();
    }
    return result.body;
}

bool match_line(const std::string &line, const std::string &pattern) {
    return trim(line) == trim(pattern);
}

// replace or append a block of text to a file, matching first and last lines if replacing.
// edits file in-place.
bool file_replace_or_add_segment(std::string filepath, std::string segment)
{
    // Create a backup of the original file
    std::string backup_path = filepath + ".bak";
    try {
        std::filesystem::copy_file(filepath, backup_path, std::filesystem::copy_options::overwrite_existing);
    } catch (const std::exception& e) {
        std::cerr << "Error creating backup file: " << e.what() << std::endl;
        return false;
    }

    // Handle empty segment
    if (segment.empty()) {
        error << "Empty segment provided" << std::endl;
        return false;
    }

    // split the segment into lines
    std::vector<std::string> segment_lines = split(segment, "\n");
    // remove empty lines
    segment_lines.erase(std::remove_if(segment_lines.begin(), segment_lines.end(), [](const std::string& line) {
        return trim(line).empty();
    }), segment_lines.end());
    // remove any lines that are just whitespace
    segment_lines.erase(std::remove_if(segment_lines.begin(), segment_lines.end(), [](const std::string& line) { return trim(line).empty(); }), segment_lines.end());
    
    // check that the segment has at least two lines
    if (segment_lines.size() < 2) {
        error << "Segment must contain at least two non-empty lines" << std::endl;
        return false;
    }

    // Read the entire file into memory
    std::ifstream input_file(filepath);
    if (!input_file.is_open()) {
        error << "Unable to open file: " << filepath << std::endl;
        return false;
    }

    std::vector<std::string> file_lines;
    std::string line;
    while (std::getline(input_file, line)) {
        file_lines.push_back(line);
    }
    input_file.close();

    // Store original file size for verification
    size_t original_size = file_lines.size();
    if (original_size == 0) {
        warning << "File is empty" << std::endl;
    }

    // Try to find the matching block
    bool found_match = false;
    for (size_t i = 0; i < file_lines.size(); i++) {
        if (match_line(file_lines[i], segment_lines[0])) {
            // Found potential start, look for end
            for (size_t j = i + 1; j < file_lines.size(); j++) {
                if (match_line(file_lines[j], segment_lines[segment_lines.size() - 1])) {
                    // Found matching block, replace it
                    file_lines.erase(file_lines.begin() + i, file_lines.begin() + j + 1);
                    file_lines.insert(file_lines.begin() + i, segment_lines.begin(), segment_lines.end());
                    
                    found_match = true;
                    break;
                }
            }
            if (found_match) break;
        }
    }

    // If no match found, append the segment
    if (!found_match) {
        file_lines.insert(file_lines.end(), segment_lines.begin(), segment_lines.end());
    }

    // Write back to file
    std::ofstream output_file(filepath);
    if (!output_file.is_open()) {
        error << "Unable to open file for writing: " << filepath << std::endl;
        return false;
    }

    for (const auto& line : file_lines) {
        output_file << line << "\n";
    }
    output_file.close();

    // If everything succeeded, remove the backup
    try {
        std::filesystem::remove(backup_path);
    } catch (const std::exception& e) {
        warning << "Could not remove backup file: " << e.what() << std::endl;
    }

    return true;
}

bool legal_service_name(const std::string &service_name) {
    static bool initialized = false;
    static bool legal_chars[256] = {false};  // Initialize all to false

    // One-time initialization
    if (!initialized) {
        // Set true for valid characters
        for (unsigned char c : "0123456789"
                              "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                              "abcdefghijklmnopqrstuvwxyz"
                              "._-") {
            legal_chars[c] = true;
        }
        initialized = true;
    }

    return std::all_of(service_name.begin(), service_name.end(),
        [](unsigned char c) { return legal_chars[c]; });
}

} // namespace dropshell