/**
 * @file config.cpp
 * @author Lewis Price (lewis.e.price@outlook.com)
 * @brief Implementation for environment utilities and cross-platform config loader
 * @version 1.0.0
 * @date 2026-06-09
 * 
 * @copyright Copyright (c) 2026
 * 
 */
#include "config.hpp"
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <filesystem>

/**
 * @brief Helper utility to set environment variables across operating systems
 */
static int set_env_variable(const std::string& key, const std::string& value) {
#if defined(_WIN32)
    return _putenv_s(key.c_str(), value.c_str());
#else
    return setenv(key.c_str(), value.c_str(), 1);
#endif
}

bool check_for_config() {
    const std::string config_path = "lumberjack.config";
    // Returns true only if lumberjack.config exists on disk and is a file (not a directory)
    return std::filesystem::exists(config_path) && std::filesystem::is_regular_file(config_path);
}

void make_config() {
    const std::string config_path = "lumberjack.config";
    if (std::filesystem::exists(config_path)) {
        return; 
    }

    std::ofstream file(config_path);
    if (!file.is_open()) {
        std::cerr << "Error: Could not generate a default " << config_path << " configuration template file." << std::endl;
        return;
    }

    // Write out the clean template configuration block
    file << "# ParseLogCLI Global Environment Configuration\n";
    file << "# Generated on 2026-06-09\n\n";
    file << "# Path to the MaxMind GeoLite2 City Database binary\n";
    file << "DB_PATH=./data/GeoLite2-City.mmdb\n\n";
    file << "# Absolute or relative path to the server access logs target file\n";
    file << "LOG_PATH=./access.log.txt\n";

    file.close();
}

void load_config_file(const std::string& config_path) {
    std::ifstream file(config_path);
    if (!file.is_open()) {
        std::cerr << "Warning: Could not open " << config_path << " file." << std::endl;
        return;
    }

    std::string line;
    while (std::getline(file, line)) {
        // Skip completely empty lines or comment configurations
        if (line.empty() || line[0] == '#') continue;

        std::size_t delimiter_pos = line.find('=');
        if (delimiter_pos != std::string::npos) {
            std::string key = line.substr(0, delimiter_pos);
            std::string value = line.substr(delimiter_pos + 1);

            // Clean up hidden trailing Windows carriage returns (\r) safely
            if (!value.empty() && value.back() == '\r') {
                value.pop_back();
            }

            // Expose the key-value pair globally to the active process lifecycle
            set_env_variable(key, value);
        }
    }
}