#include <iostream>
#include <filesystem>
#include <fstream>
#include <string>
#include <chrono>
#include <vector>
#include <windows.h>
#include <libloaderapi.h>

#include <nlohmann/json.hpp>

using std::string;
using json = nlohmann::json;

const int VERSION_MAJOR = 0;
const int VERSION_MINOR = 1;

enum Flags {
    EMPTY_FILES = 0x1,
    EMPTY_DIRECTORIES = 0x2
};

// DWORD GetModuleFileNameA(
//   [in, optional] HMODULE hModule,
//   [out]          LPSTR   lpFilename,
//   [in]           DWORD   nSize
// );

struct DirectoryEntry
{
    std::filesystem::path path;
    unsigned char flags = EMPTY_DIRECTORIES | EMPTY_FILES;
    std::chrono::duration<int> olderThan = std::chrono::duration<int>(0);

    void
    clear()
    {
        path = std::filesystem::path();
        flags = EMPTY_DIRECTORIES | EMPTY_FILES;
        olderThan = std::chrono::duration<int>(0);
    }
};

string
getVersion()
{
    return std::to_string(VERSION_MAJOR)+"."+std::to_string(VERSION_MINOR);
}

void
print_usage()
{
    std::cout << "--------------------------\n"<< "Cleaner version " << getVersion() << "\n--------------------------\n";
    std::cout << "\tUsage:\n\t\tcleaner\n";
}


bool 
createDefaultConfig()
{
    LPSTR   lpFilename;
    DWORD   nSize = 256;
    DWORD   len;

    len = GetModuleFileName(NULL, lpFilename, nSize);
    OutputDebugString(lpFilename);

    json config;
    config["version"] = getVersion();
    config["directories"][0]["directory"] = "C:/dev/temp";
    config["directories"][0]["rules"]["empty_directories"] = true;
    config["directories"][0]["rules"]["empty_files"] = true;
    config["directories"][0]["rules"]["age"] = "30d";

    string output = config.dump(4);
    std::ofstream f("cleaner.json");
    if (f.is_open()) 
    {
        f << output << std::endl;
        f.close();
        return true;
    }
    return false;
    // Return file handle?
}

void
cleanEntries(std::vector<DirectoryEntry>& entries)
{
    for(auto& entry : entries)
    {
        std::cout << entry.path.string() << "\n";
    }
}

std::chrono::duration<int>
parseAge(string age)
{
    //TODO (Eero): parse age i.e. 30d
    return std::chrono::duration<int>(0);
}

void
parseConfig(std::vector<DirectoryEntry>& entries)
{
    if(!std::filesystem::exists(std::filesystem::path("./cleaner.json")))
    {
        std::cout << "Didn't find cleaner.json. Creating default configuration into cleaner.json.\n";
        // Create cleaner.json
        if(!createDefaultConfig())
        {
            // Failed to create file for some reason. Exit from function.
            return;
        }
    }
    //TODO (Eero): Check version here
    std::ifstream f("cleaner.json");
    json config = json::parse(f);
    std::cout << "Config version: " << config["version"].template get<string>() << "\n";
    // Iterate directories
    DirectoryEntry entry = {};
    for (auto& element : config["directories"]) {
        if(element.is_string())
        {
            entry.path = std::filesystem::path(element.template get<string>());
            entries.push_back(entry);
            entry.clear();
            continue;
        }
        entry.path = std::filesystem::path(element["directory"].template get<string>());
        //TODO (Eero): Check if rules exists
        for(json::iterator it = element["rules"].begin(); it != element["rules"].end();++it)
        {
            if(it.key() == "empty_directories")
            {
                entry.flags |= EMPTY_DIRECTORIES;
            }
            if(it.key() == "empty_files")
            {
                entry.flags |= EMPTY_FILES;
            }
            if(it.key() == "age")
            {
                entry.olderThan = parseAge(it.value());
            }
        }
        entries.push_back(entry);
        entry.clear();
    }
}

int 
main(int argc, char const *argv[])
{
    if(argc>1){
        print_usage();
        return 0;
    }
    std::vector<DirectoryEntry> entries = {};
    const auto start = std::chrono::steady_clock::now();
    parseConfig(entries);
    cleanEntries(entries);
    const auto end = std::chrono::steady_clock::now();
    const std::chrono::duration<double> elapsed_seconds{end - start};
    std::cout << "Cleaner finished after " << elapsed_seconds.count() << "s\n";
    return 0;
}