#ifndef HUMANUS_CONFIG_H
#define HUMANUS_CONFIG_H

#include <string>
#include <map>
#include <fstream>
#include <sstream>
#include <mutex>
#include <filesystem>
#include <memory>

#include "schema.h"
#include "prompt.h"

namespace humanus {

// Get project root directory
static std::filesystem::path get_project_root() {
    return std::filesystem::path(__FILE__).parent_path();
}

static const std::filesystem::path PROJECT_ROOT = get_project_root();

struct LLMConfig {
    std::string model;
    std::string api_key;
    std::string base_url;
    std::string end_point;
    int max_tokens;
    int timeout;
    double temperature;
    bool oai_tool_support;

    LLMConfig(
        const std::string& model = "deepseek-chat", 
        const std::string& api_key = "sk-", 
        const std::string& base_url = "https://api.deepseek.com", 
        const std::string& end_point = "/v1/chat/completions",
        int max_tokens = 4096, 
        int timeout = 120, 
        double temperature = 1.0,
        bool oai_tool_support = true
    ) : model(model), api_key(api_key), base_url(base_url), end_point(end_point),
        max_tokens(max_tokens), timeout(timeout), temperature(temperature), oai_tool_support(oai_tool_support) {}
        
    json to_json() const {
        json j;
        j["model"] = model;
        j["api_key"] = api_key;
        j["base_url"] = base_url;
        j["end_point"] = end_point;
        j["max_tokens"] = max_tokens;
        j["temperature"] = temperature;
        return j;
    }
};

struct ToolParser {
    std::string tool_start;
    std::string tool_end;
    std::string tool_hint_template;

    ToolParser(const std::string& tool_start = "<tool_call>", const std::string& tool_end = "</tool_call>", const std::string& tool_hint_template = prompt::toolcall::TOOL_HINT_TEMPLATE)
        : tool_start(tool_start), tool_end(tool_end), tool_hint_template(tool_hint_template) {}

    static ToolParser get_instance() {
        static ToolParser instance;
        return instance;
    }

    static std::string str_replace(std::string& str, const std::string& from, const std::string& to) {
        size_t start_pos = 0;
        while ((start_pos = str.find(from, start_pos)) != std::string::npos) {
            str.replace(start_pos, from.length(), to);
            start_pos += to.length(); // In case 'to' contains 'from', like replacing 'x' with 'yx'
        }
        return str;
    }

    std::string hint(const std::string& tool_list) const {
        std::string hint_str = tool_hint_template;
        hint_str = str_replace(hint_str, "{tool_start}", tool_start);
        hint_str = str_replace(hint_str, "{tool_end}", tool_end);
        hint_str = str_replace(hint_str, "{tool_list}", tool_list);
        return hint_str;
    }

    json parse(const std::string& content) const {
        std::string new_content = content;
        json tool_calls = json::array();

        size_t pos_start = new_content.find(tool_start);
        size_t pos_end = pos_start == std::string::npos ? std::string::npos : new_content.find(tool_end, pos_start + tool_start.size());

        if (pos_start != std::string::npos && pos_end == std::string::npos) { // Some might not have tool_end
            pos_end = new_content.size();
        }

        while (pos_start != std::string::npos) {
            std::string tool_content = new_content.substr(pos_start + tool_start.size(), pos_end - pos_start - tool_start.size());
            
            if (!tool_content.empty()) {
                try {
                    tool_calls.push_back({
                        {"type", "function"},
                        {"function", json::parse(tool_content)}
                    });
                    tool_calls.back()["id"] = "call_" + std::to_string(std::chrono::system_clock::now().time_since_epoch().count());
                } catch (const json::exception& e) {
                    throw std::runtime_error("Invalid tool call: " + tool_content);
                }
            }

            auto trim = [](const std::string& str) -> std::string {
                auto not_space = [](unsigned char ch) { return !std::isspace(ch); };

                auto start = std::find_if(str.begin(), str.end(), not_space);
                auto end = std::find_if(str.rbegin(), str.rend(), not_space).base();

                if (start >= end) return "";
                return std::string(start, end);
            };

            std::string lhs = trim(new_content.substr(0, pos_start));
            std::string rhs = trim(new_content.substr(std::min(pos_end + tool_end.size(), new_content.size())));

            new_content = lhs + rhs;

            pos_start = new_content.find(tool_start, pos_start); // Previous tool_call has been cut off
            pos_end = pos_start == std::string::npos ? std::string::npos : new_content.find(tool_end, pos_start + tool_start.size());
            if (pos_start != std::string::npos && pos_end == std::string::npos) { // Some might not have tool_end
                pos_end = new_content.size();
            }
        }

        return {
            {"content", new_content},
            {"tool_calls", tool_calls} // Might be empty if no tool calls found
        };
    }

    json dump(const json& tool_calls) const {
        std::string content;
        if (!tool_calls.is_array()) {
            throw std::runtime_error("Tool calls should be an array");
        }
        for (const auto& tool_call : tool_calls) {
            content += tool_start;
            content += tool_call[tool_call["type"]].dump(2);
            content += tool_end;
        }
        return content;
    }
};

struct AppConfig {
    std::map<std::string, LLMConfig> llm;
    std::map<std::string, ToolParser> tool_parser;
};

class Config {
private:
    static Config* _instance;
    static std::mutex _mutex;
    bool _initialized = false;
    AppConfig _config;
    
    Config() {
        _load_initial_config();
        _initialized = true;
    }
    
    Config(const Config&) = delete;
    Config& operator=(const Config&) = delete;
    
    /**
     * @brief Get the config path
     * @return The config path
     */
    static std::filesystem::path _get_config_path() {
        auto root = PROJECT_ROOT;
        auto config_path = root / "config" / "config_llm.toml";
        if (std::filesystem::exists(config_path)) {
            return config_path;
        }
        throw std::runtime_error("Config file not found");
    }
    
    /**
     * @brief Load the initial config
     */
    void _load_initial_config();

public:
    /**
     * @brief Get the singleton instance
     * @return The config instance
     */
    static Config& get_instance() {
        if (_instance == nullptr) {
            std::lock_guard<std::mutex> lock(_mutex);
            if (_instance == nullptr) {
                _instance = new Config();
            }
        }
        return *_instance;
    }
    
    /**
     * @brief Get the LLM settings
     * @return The LLM settings map
     */
    const std::map<std::string, LLMConfig>& llm() const {
        return _config.llm;
    }

    /**
     * @brief Get the tool helpers
     * @return The tool helpers map
     */
    const std::map<std::string, ToolParser>& tool_parser() const {
        return _config.tool_parser;
    }
    
    /**
     * @brief Get the app config
     * @return The app config
     */
    const AppConfig& get_config() const {
        return _config;
    }
};

} // namespace humanus

#endif // HUMANUS_CONFIG_H