#include <iostream>
#include <fstream>
#include <sstream>
#include <cstdlib>
#include <chrono>
#include <iomanip>
#include <filesystem>
#include <unistd.h>
#include "utils/assert.hpp"

#include "config.hpp"
#include "server_env_manager.hpp"
#include "templates.hpp"
#include "services.hpp"
#include "utils/directories.hpp"
#include "utils/utils.hpp"
#include "command_registry.hpp"
#include "shared_commands.hpp"




namespace dropshell {



class service_runner {
    public:
        service_runner(const std::string& server_name, const std::string& service_name);
        bool isValid() const { return mValid; }

        // run a command over ssh, using the credentials from server.env (via server_env.hpp)
        // first check that the command corresponds to a valid .sh file in the service directory
        // then run the command, passing the {service_name}.env file as an argument
        // do a lot of checks, such as:
        // checking that we can ssh to the server.
        // checking whether the service directory exists on the server.
        // checking that the command exists in the service directory.
        // checking that the command is a valid .sh file.
        // checking that the {service_name}.env file exists in the service directory.
        bool run_command(const std::string& command, std::vector<std::string> additional_args={}, std::map<std::string, std::string> env_vars={});

        // check health of service. Silent.
        // 1. run status.sh on the server
        // 2. return the output of the status.sh script

        //HealthStatus is_healthy();

        // std::string healthtick();
        // std::string healthmark();

    public:            
        // backup and restore
        bool backup(bool silent=false);
        bool restore(std::string backup_file, bool silent=false);

        // nuke the service
        bool nuke(bool silent=false); // nukes all data for this service on the remote server
        bool fullnuke(); // nuke all data for this service on the remote server, and then nukes all the local service definitionfiles

        // launch an interactive ssh session on a server or service
        // replaces the current dropshell process with the ssh process
        bool interactive_ssh_service();

        bool scp_file_to_remote(const std::string& local_path, const std::string& remote_path, bool silent=false);
        bool scp_file_from_remote(const std::string& remote_path, const std::string& local_path, bool silent=false);
    public:
        // utility functions
        static std::string get_latest_backup_file(const std::string& server, const std::string& service);
        static bool interactive_ssh(const std::string & server_name, const std::string & command);
        // static std::map<std::string, ServiceStatus> get_all_services_status(std::string server_name);

    private:
        std::string mServer;
        server_env_manager mServerEnv;
        LocalServiceInfo mServiceInfo;
        std::string mService;
        bool mValid;

        // Helper methods
    public:
};


} // namespace dropshell



namespace fs = std::filesystem;

namespace dropshell {


service_runner::service_runner(const std::string& server_name, const std::string& service_name) : 
    mServerEnv(server_name), mServer(server_name), mService(service_name), mValid(false)
{
    if (server_name.empty() || service_name.empty())
        return; 

    // Initialize server environment
    if (!mServerEnv.is_valid()) 
        return;

    mServiceInfo = get_service_info(server_name, service_name);
    if (mServiceInfo.service_name.empty())
        return;

    mService = mServiceInfo.service_name;
    
    mValid = !mServiceInfo.local_template_path.empty();
}



bool service_runner::nuke(bool silent)
{
    maketitle("Nuking " + mService + " (" + mServiceInfo.template_name + ") on " + mServer);

    if (!mServerEnv.is_valid()) return false; // should never hit this.

    std::string remote_service_path = remotepath::service(mServer, mService);

    info << "Service " << mService << " successfully nuked from " << mServer << std::endl;

    if (!silent) {
        info << "There's nothing left on the remote server." << std::endl;
        info << "You can remove the local files with:" << std::endl;
        info << "   rm -rf " << localpath::service(mServer,mService) << std::endl;
    }
    return true;
}

bool service_runner::fullnuke()
{
    if (!nuke(true))
    {
        warning << "Nuke script failed, aborting." << std::endl;
        return false;
    }

    std::string local_service_path = mServiceInfo.local_service_path;
    if (local_service_path.empty() || !fs::exists(local_service_path)) {
        error << "Service directory not found: " << local_service_path << std::endl;
        return false;
    }  
    
    std::string rm_cmd = "rm -rf " + quote(local_service_path);
    if (!execute_local_command("", rm_cmd, {}, nullptr, cMode::Silent)) {
        error << "Failed to remove service directory" << std::endl;
        return false;
    }
    
    return true;
}


// ------------------------------------------------------------------------------------------------
// Run a command on the service.
// ------------------------------------------------------------------------------------------------
bool service_runner::run_command(const std::string& command, std::vector<std::string> additional_args, std::map<std::string, std::string> env_vars) {
    if (!mServerEnv.is_valid()) {
        std::cerr << "Error: Server service not initialized" << std::endl;
        return false;
    }
    template_info tinfo = gTemplateManager().get_template_info(mServiceInfo.template_name);
    if (!tinfo.is_set()) {
        std::cerr << "Error: Template '" << mServiceInfo.template_name << "' not found" << std::endl;
        return false;
    }

    if (command == "fullnuke") 
        return fullnuke();

    if (command == "nuke") 
    {
        std::cout << "Nuking " << mService << " (" << mServiceInfo.template_name << ") on " << mServer << std::endl;
        return nuke();
    }

    if (!gTemplateManager().template_command_exists(mServiceInfo.template_name, command)) {
        std::cout << "No command script for " << mServiceInfo.template_name << " : " << command << std::endl;
        return true; // nothing to run.
    }

    // install doesn't require anything on the server yet.
    // if (command == "install") 
    //     return install_service(mServer, mService, false);

    std::string script_path = remotepath::service_template(mServer, mService) + "/" + command + ".sh";
    
    // Check if service directory exists
    if (!mServerEnv.check_remote_dir_exists(remotepath::service(mServer, mService))) {
        std::cerr << "Error: Service is not installed: " << mService << std::endl;
        return false;
    }
    
    // Check if command script exists
    if (!mServerEnv.check_remote_file_exists(script_path)) {
        std::cerr << "Error: Remote command script not found: " << script_path << std::endl;
        return false;
    }

    // Check if env file exists
    if (!mServerEnv.check_remote_file_exists(remotefile::service_env(mServer, mService))) {
        std::cerr << "Error: Service config file not found: " << remotefile::service_env(mServer, mService) << std::endl;
        return false;
    }

    // if (command == "uninstall") 
    //     return uninstall();

    if (command == "ssh") {
        interactive_ssh_service();
        return true;
    }
    if (command == "restore") {
        if (additional_args.size() < 1) {
            std::cerr << "Error: restore requires a backup file:" << std::endl;
            std::cerr << "dropshell restore <server> <service> <backup-file>" << std::endl;
            return false;
        }
        return restore(additional_args[0], false);
    }
    if (command == "backup") {
        return backup(false);
    }

    // Run the generic command
    std::vector<std::string> args; // not passed through yet.
    return mServerEnv.run_remote_template_command(mService, command, args, false, env_vars);
}



bool service_runner::interactive_ssh(const std::string & server_name, const std::string & command) {
    std::string serverpath = localpath::server(server_name);
    if (serverpath.empty()) {
        std::cerr << "Error: Server not found: " << server_name << std::endl;
        return false;
    }
    
    server_env_manager env(server_name);
    if (!env.is_valid()) {
        std::cerr << "Error: Invalid server environment file: " << server_name << std::endl;
        return false;
    }
    sCommand scommand("", "bash",{});
    return execute_ssh_command(env.get_SSH_INFO(), scommand, cMode::Interactive);
}



bool service_runner::interactive_ssh_service()
{
    std::set<std::string> used_commands = get_used_commands(mServer, mService);
    if (used_commands.find("ssh") == used_commands.end()) {
        std::cerr << "Error: "<< mService <<" does not support ssh" << std::endl;
        return false;
    }

    std::vector<std::string> args; // not passed through yet.
    return mServerEnv.run_remote_template_command(mService, "ssh", args, false, {});
}

bool service_runner::scp_file_to_remote(const std::string &local_path, const std::string &remote_path, bool silent)
{
    std::string scp_cmd = "scp -P " + mServerEnv.get_SSH_PORT() + " " + quote(local_path) + " " + mServerEnv.get_SSH_USER() + "@" + mServerEnv.get_SSH_HOST() + ":" + quote(remote_path) + (silent ? " > /dev/null 2>&1" : "");
    return execute_local_command("", scp_cmd, {}, nullptr, (silent ? cMode::Silent : cMode::Defaults));
}

bool service_runner::scp_file_from_remote(const std::string &remote_path, const std::string &local_path, bool silent)
{
    std::string scp_cmd = "scp -P " + mServerEnv.get_SSH_PORT() + " " + mServerEnv.get_SSH_USER() + "@" + mServerEnv.get_SSH_HOST() + ":" + quote(remote_path) + " " + quote(local_path) + (silent ? " > /dev/null 2>&1" : "");
    return execute_local_command("", scp_cmd, {}, nullptr, (silent ? cMode::Silent : cMode::Defaults));
}

bool service_runner::restore(std::string backup_file, bool silent)
{
    if (backup_file.empty()) {
        std::cerr << "Error: not enough arguments.  dropshell restore <server> <service> <backup-file>" << std::endl;
        return false;
    }

    std::string local_backups_dir = gConfig().get_local_backup_path();

    if (backup_file == "latest") {
        // get the latest backup file from the server
        backup_file = get_latest_backup_file(mServer, mService);
    }

    std::string local_backup_file_path = (std::filesystem::path(local_backups_dir) / backup_file).string();

    if (! std::filesystem::exists(local_backup_file_path)) {
        std::cerr << "Error: Backup file not found at " << local_backup_file_path << std::endl;
        return false;
    }

    // split the backup filename into parts based on the magic string
    std::vector<std::string> parts = dropshell::split(backup_file, "-_-");
    if (parts.size() != 4) {
        std::cerr << "Error: Backup file format is incompatible, - in one of the names?" << std::endl;
        return false;
    }

    std::string backup_server_name = parts[0];
    std::string backup_template_name = parts[1];
    std::string backup_service_name = parts[2];
    std::string backup_datetime = parts[3];

    if (backup_template_name != mServiceInfo.template_name) {
        std::cerr << "Error: Backup template does not match service template. Can't restore." << std::endl;
        return false;
    }

    std::string nicedate = std::string(backup_datetime).substr(0, 10);

    std::cout << "Restoring " << nicedate << " backup of " << backup_template_name << " taken from "<<backup_server_name<<", onto "<<mServer<<"/"<<mService<<std::endl;
    std::cout << std::endl;
    std::cout << "*** ALL DATA FOR "<<mServer<<"/"<<mService<<" WILL BE OVERWRITTEN! ***"<<std::endl;

    // run the restore script
    std::cout << "OK, here goes..." << std::endl;

    { // backup existing service
        maketitle("1) Backing up old service... ");
        if (!backup(true)) // silent=true
        {
            std::cerr << std::endl;
            std::cerr << "Error: Backup failed, restore aborted." << std::endl;
            std::cerr << "You can try using   dropshell install "<<mServer<<" "<<mService<<"   to install the service afresh." << std::endl;
            std::cerr << "Otherwise, stop the service, create and initialise a new one, then restore to that." << std::endl;
            return false;
        }
        std::cout << "Backup complete." << std::endl;
    }

    { // uninstall service, then nuke it.
        maketitle("2) Uninstalling old service...");
        // if (!uninstall(true))
        //     return false;

        maketitle("3) Nuking old service...");
        // if (!nuke(true))
        //     return false;
    }


    { // restore service from backup
        maketitle("4) Restoring service data from backup...");
        std::string remote_backups_dir = remotepath::backups(mServer);
        std::string remote_backup_file_path = remote_backups_dir + "/" + backup_file;

        // Copy backup file from local to server
        if (!scp_file_to_remote(local_backup_file_path, remote_backup_file_path, silent)) {
            std::cerr << "Failed to copy backup file from local to server" << std::endl;
            return false;
        }

        shared_commands::cRemoteTempFolder remote_temp_folder(mServerEnv);
        mServerEnv.run_remote_template_command(mService, "restore", {}, silent, {{"BACKUP_FILE", remote_backup_file_path}, {"TEMP_DIR", remote_temp_folder.path()}});
    } // dtor of remote_temp_folder will clean up the temp folder on the server


    // { // installing fresh service
    //     maketitle("5) Non-destructive install of fresh service...");
    //     if (!install_service(mServer, mService, true))
    //         return false;
    // }

    bool healthy = false;
    {// healthcheck the service
        maketitle("6) Healthchecking service...");
        std::string green_tick = "\033[32m✓\033[0m";
        std::string red_cross = "\033[31m✗\033[0m";    
        healthy= (mServerEnv.run_remote_template_command(mService, "status", {}, silent, {}));
        if (!silent)
            std::cout << (healthy ? green_tick : red_cross) << " Service is " << (healthy ? "healthy" : "NOT healthy") << std::endl;
    }

    return healthy;
}


// backup the service over ssh, using the credentials from server.env (via server_env.hpp)
// 1. run backup.sh on the server
// 2. create a backup file with format server-service-datetime.tgz
// 3. store it in the server's DROPSHELL_DIR/backups folder
// 4. copy it to the local user_dir/backups folder

// ------------------------------------------------------------------------------------------------
// Backup the service.
// ------------------------------------------------------------------------------------------------
bool service_runner::backup(bool silent) {
    auto service_info = get_service_info(mServer, mService);
    if (service_info.local_service_path.empty()) {
        std::cerr << "Error: Service not found" << std::endl;
        return 1;
    }

    const std::string command = "backup";

    if (!gTemplateManager().template_command_exists(service_info.template_name, command)) {
        std::cout << "No backup script for " << service_info.template_name << std::endl;
        return true; // nothing to back up.
    }
    
    // Check if basic installed stuff is in place.
    std::string remote_service_template_path = remotepath::service_template(mServer, mService);
    std::string remote_command_script_file = remote_service_template_path + "/" + command + ".sh";
    std::string remote_service_config_path = remotepath::service_config(mServer, mService);
    if (!mServerEnv.check_remote_items_exist({
        remotepath::service(mServer, mService),
        remote_command_script_file,
        remotefile::service_env(mServer, mService)})
    )
    {
        std::cerr << "Error: Required service directories not found on remote server" << std::endl;
        std::cerr << "Is the service installed?" << std::endl;
        return false;
    }

    // Create backups directory on server if it doesn't exist
    std::string remote_backups_dir = remotepath::backups(mServer);
    if (!silent) std::cout << "Remote backups directory on "<< mServer <<": " << remote_backups_dir << std::endl;
    std::string mkdir_cmd = "mkdir -p " + quote(remote_backups_dir);
    if (!execute_ssh_command(mServerEnv.get_SSH_INFO(), sCommand("",mkdir_cmd, {}), cMode::Silent)) {
        std::cerr << "Failed to create backups directory on server" << std::endl;
        return false;
    }

    // Create backups directory locally if it doesn't exist
    std::string local_backups_dir = gConfig().get_local_backup_path();
    if (local_backups_dir.empty()) {
        std::cerr << "Error: Local backups directory not found" << std::endl;
        std::cerr << "Run 'dropshell edit' to configure DropShell" << std::endl;
        return false;
    }
    if (!std::filesystem::exists(local_backups_dir)) 
        std::filesystem::create_directories(local_backups_dir);

    // Get current datetime for backup filename
    auto now = std::chrono::system_clock::now();
    auto time = std::chrono::system_clock::to_time_t(now);
    std::stringstream datetime;
    datetime << std::put_time(std::localtime(&time), "%Y-%m-%d_%H-%M-%S");
    
    // Construct backup filename
    shared_commands::cBackupFileName backup_filename_construction(mServer, mService, service_info.template_name);
    if (!backup_filename_construction.is_valid()) {
        std::cerr << "Invalid backup filename" << std::endl;
        return false;
    }
    std::string backup_filename = backup_filename_construction.get_filename();
    std::string remote_backup_file_path = remote_backups_dir + "/" + backup_filename;
    std::string local_backup_file_path = (std::filesystem::path(local_backups_dir) / backup_filename).string();

    // assert that the backup filename is valid - -_- appears exactly 3 times in local_backup_file_path.
    ASSERT(3 == count_substring("-_-", local_backup_file_path), "Invalid backup filename");

    {   // Run backup script
        shared_commands::cRemoteTempFolder remote_temp_folder(mServerEnv);
        if (!mServerEnv.run_remote_template_command(mService, command, {}, silent, {{"BACKUP_FILE", remote_backup_file_path}, {"TEMP_DIR", remote_temp_folder.path()}})) {
            std::cerr << "Backup script failed on remote server: " << remote_backup_file_path << std::endl;
            return false;
        }

        // Copy backup file from server to local
        if (!scp_file_from_remote(remote_backup_file_path, local_backup_file_path, silent)) {
            std::cerr << "Failed to copy backup file from server" << std::endl;
            return false;
        }
    } // dtor of remote_temp_folder will clean up the temp folder on the server

    if (!silent) {
        std::cout << "Backup created successfully. Restore with:"<<std::endl;
        std::cout << "   dropshell restore " << mServer << " " << mService << " " << backup_filename << std::endl;
    }
    return true;
}

// Helper function to get the latest backup file for a given server and service
std::string service_runner::get_latest_backup_file(const std::string& server, const std::string& service) {
    std::string local_backups_dir = gConfig().get_local_backup_path();
    if (local_backups_dir.empty() || !std::filesystem::exists(local_backups_dir)) {
        std::cerr << "Error: Local backups directory not found: " << local_backups_dir << std::endl;
        return "";
    }

    // Get the template name for this service
    LocalServiceInfo info = get_service_info(server, service);
    if (info.template_name.empty()) {
        std::cerr << "Error: Could not determine template name for service: " << service << std::endl;
        return "";
    }

    // Build the expected prefix for backup files
    std::string prefix = server + "-_-" + info.template_name + "-_-" + service + "-_-";
    std::string latest_file;
    std::string latest_datetime;

    std::cout << "Looking for backup files in " << local_backups_dir << std::endl;

    for (const auto& entry : std::filesystem::directory_iterator(local_backups_dir)) {
        if (!entry.is_regular_file()) continue;
        std::string filename = entry.path().filename().string();
        if (filename.rfind(prefix, 0) == 0) { // starts with prefix
            // Extract the datetime part
            size_t dt_start = prefix.size();
            size_t dt_end = filename.find(".tgz", dt_start);
            if (dt_end == std::string::npos) continue;
            std::string datetime = filename.substr(dt_start, dt_end - dt_start);
            std::cout << "Found backup file: " << filename << " with datetime: " << datetime << std::endl;
            if (datetime > latest_datetime) {
                latest_datetime = datetime;
                latest_file = filename;
            }
        }
    }

    if (latest_file.empty()) {
        std::cerr << "Error: No backup files found for " << server << ", " << service << std::endl;
    }

    std::cout << "Latest backup file: " << latest_file << std::endl;
    return latest_file;
}

} // namespace dropshell