#pragma once
#include <iostream>
#include <fstream>
#include <filesystem>
#include <vector>
#include <sys/stat.h>
namespace qing {
/* 子系统类 */
class Modules {
public:
    /* 传入子系统的路径 然后验证是否存在 */
    Modules(std::string& mods) {
        this->home = mods;
        if (!is_exist(this->home))
            throw SubsystemNotExist(mods);
    }
    
    /* 
     * 获取子系统下某个模块的启动脚本路径
     *
     * NOTE: 防注入检查是必须的
     */
    std::string GetInitp(std::string name) {
        std::string ret = get_mod_init_path(name);
        if (is_exist(ret)) {
            return ret;
        }
        else {
            throw InitScriptNotExist(ret);
        }
    }
    
    /*
     * 列出子系统下的所有模块
     *
     * 优化建议：做抽象层表示模块概念
     */
    std::vector<std::string> ListAll() {
        std::vector<std::string> folders;
        try {
            for (const auto& entry: std::filesystem::directory_iterator(this->home))
                if (entry.is_directory())
                    folders.push_back(entry.path().filename().string());
        }
        catch(const std::filesystem::filesystem_error& e) {
            ListModulesFailed(this->home, e.what());
        }
        return folders;
    }

    /* 在该子系统下创建一个初始模块 */
    void CrtMod(std::string &name) {
        crt_mod_dir(name);
        init_mod_dir(name);
        init_mod_man(name);
        grd_priv(name);
    }
    
    /* 删除子系统下一个模块 */
    void DelMod(std::string &name) {
        std::string fullpath = get_mod_path(name);
        deleteDirectory(fullpath);
    }

    /* 子系统异常模块 */
    class Mods_Exp: public std::runtime_error {
        public:
        explicit Mods_Exp(const std::string& msg): std::runtime_error(msg) {
            ;
        }
    };
    
    /* 子系统不存在异常 */
    class SubsystemNotExist: public Mods_Exp {
    public:
        explicit SubsystemNotExist(const std::string &name): Mods_Exp("Target subsystem " + name + " not exists.") {
            ;
        }
    };
    
    /* 启动脚本不存在异常 */
    class InitScriptNotExist: public Mods_Exp {
    public:
        explicit InitScriptNotExist(const std::string &name): Mods_Exp("Target init script " + name + " not exists") {
            ;
        }
    };
    
    /* 列举模块失败异常 */
    class ListModulesFailed: public  Mods_Exp {
        public:
        explicit ListModulesFailed(const std::string &name, const std::string &reson): Mods_Exp("Error when read subsystem <" + name + "> , because " + reson) {
            ;
        }
    };
    
    /* 要创建的路径已经存在 */
    class AlreadyExist: public Mods_Exp {
        public:
        explicit AlreadyExist(const std::string &name): Mods_Exp(name) {
            ;
        }
    };
    
    /* 创建失败 */
    class CreateFailed: public Mods_Exp {
        public:
        explicit CreateFailed(const std::string &name): Mods_Exp(name) {
            ;
        }
    };
    
    /* 提升权限失败 */
    class GrandPrivilegesFailed: public Mods_Exp {
        public:
        explicit GrandPrivilegesFailed(const std::string &name): Mods_Exp(name) {
            ;
        }
    };
     
    /* 删除失败 */
    class DeleteFailed: public Mods_Exp {
        public:
        explicit DeleteFailed(const std::string &name): Mods_Exp(name) {
            ;
        }
    };
    
private:

    /* 子系统的模块目录 */
    std::string home;

    /* 创建模块目录*/
    void crt_mod_dir(std::string name) {
        std::string fullpath = get_mod_path(name);
        if (is_exist(fullpath)) {
            throw AlreadyExist(name);
        } else {
            std::filesystem::create_directory(fullpath);
        }
    }

    /* 初始化模块目录，创建启动脚本 */
    void init_mod_dir(std::string name) {
        std::string fullpath = get_mod_init_path(name);
        if (is_exist(fullpath)) {
            throw AlreadyExist(name);
        }
        else {
            std::ofstream outFile = std::ofstream(fullpath);
            if (outFile) {
                outFile << "#!/bin/bash\n";
                outFile << "cd \"$(dirname \"$0\")\" || exit\n\n";
                outFile << "exec echo hello!";
            } else {
                throw CreateFailed(name);
            }
        }
    }

    /* 初始化一个模块的手册（README.md）*/
    void init_mod_man(std::string name) {
        std::string fullpath = get_mod_man_path(name);
        if(is_exist(fullpath)) {
            throw AlreadyExist(fullpath);
        }
        else {
            std::ofstream outFile = std::ofstream(fullpath);
            if (outFile) {
                outFile << "# ";
                outFile << name;
                outFile << "\n";
            } else {
                throw CreateFailed(name);
            }
        }
    }

    /* 获取模块的路径 */
    std::string get_mod_path(std::string &name) {
        return this->home + get_sep() + name;
    }

    /* 获取模块的启动脚本路径 */
    std::string get_mod_init_path(std::string &name) {
        return get_mod_path(name) + get_sep()+ "_run.sh";
    }

    /* 获取模块的手册路径 */
    std::string get_mod_man_path(std::string &name) {
        return get_mod_path(name) + get_sep()+ "README.md";
    }
    
    /* 赋予一个文件755权限 */
    void grd_priv(std::string &name) {
        std::string fullpath = get_mod_init_path(name);
        if (chmod(fullpath.c_str(), 0755) == -1) {
            throw GrandPrivilegesFailed("path");
        }
    }
    
    /* 获取当前可执行程序所在目录 */
    static std::string get_curr() {
        return std::filesystem::canonical("/proc/self/exe").parent_path().string();
    }
    
    /* 文件是否存在 */
    static bool is_exist(std::string &path) {
        return std::filesystem::exists(path);
    }
    
    /* 获取文件系统分隔符号 */
    static char get_sep() {
        return std::filesystem::path::preferred_separator;
    }
    
    /* 删除一整个文件夹 */
    static void deleteDirectory(const std::filesystem::path& path) {
        try { /* 递归 */
            std::filesystem::remove_all(path) > 0;
        }
        catch (const std::filesystem::filesystem_error& e) {
            throw DeleteFailed(e.what());
        }
    }

};
}