#include <iostream>
#include <cctype>
#include <pEp/pEpEngine.h>
#include <pEp/message_api.h>
#include <pEp/keymanagement.h>
#include <pEp/identity_list.h>
#include <pEp/utils.hh>
#include <pEp/pEpLog.hh>
#include <pEp/inspect.hh>
#include <type_traits>


namespace pEp {

    char* alloc_str(const std::string& str)
    {
        char* ret = strdup(str.c_str());
        pEpLog(CXX::Inspect::all(ret));
        return ret;
    }

    template<class T>
    void free(T ptr_type)
    {
        pEpLog(CXX::Inspect::all(ptr_type));
        ::pEp_free(ptr_type);
    }

    template<>
    void free(char* ptr_type)
    {
        pEpLog(CXX::Inspect::all(ptr_type));
        ::pEp_free(ptr_type);
    }

    template<>
    void free(::pEp_identity* ptr_type)
    {
        pEpLog(CXX::Inspect::all(ptr_type));
        ::pEp_free(ptr_type);
    }


//---------------------------------------------------------------------------------------------
#define EXSTR(msg) std::string(__FUNCTION__) + " - " + msg

    template<class T>
    class POD {
        static_assert(std::is_pod<T>::value && !std::is_pointer<T>::value, "not an integral");

    public:
        POD() = delete;

        explicit POD(T* pod_p)
        {
            if (pod_p == nullptr) {
                throw Exception{ EXSTR("cant init on a nullptr") };
            }
            _pod_p = pod_p;
            pEpLogClass(to_string() + " - taking ownership");
        }

        // make a copy
        POD& operator=(T value)
        {
            pEpLogClass("Before: " + to_string() + " - new val: '" + CXX::Inspect::val(value) + "'");
            *_pod_p = value;
            pEpLogClass("After:  " + to_string());
            return *this;
        }

        // return a copy
        operator T() const
        {
            return *_pod_p;
        }

        // return address of the wrappee
        T* data()
        {
            return _pod_p;
        }

        // return address of the wrappee (const)
        const T* c_data() const
        {
            return _pod_p;
        }

        std::string to_string() const
        {
            std::string ret{ "[" + CXX::Inspect::all(_pod_p) + "]" };
            return ret;
        }

        static bool log_enabled;

    private:
        T* _pod_p{ nullptr };

        Adapter::pEpLog::pEpLogger logger{ "pEp::POD", log_enabled };
        Adapter::pEpLog::pEpLogger& m4gic_logger_n4me = logger;

        class Exception : public std::runtime_error {
        public:
            explicit Exception(const std::string& msg) : std::runtime_error(msg) {}
        };
    };

    template<class T>
    bool pEp::POD<T>::log_enabled{ true };

    template<class T>
    std::ostream& operator<<(std::ostream& o, pEp::POD<T> pEpEnum)
    {
        return o << (int)pEpEnum;
    }

    //---------------------------------------------------------------------------------------------
    // Manages a char* to appear like a std::string
    // char* c_str
    // c_str MUST point to either:
    // * NULL - means there is no value/mem alloc yet
    // * dyn allocated memory
    // in case the mem is already allocated, there must be 2 modes
    // * take ownership (and free it)
    // * dont take ownership, only provide a C++ interface
    // There must be the option to construct the object before the wrapped c_str (char*)
    // is known. This leads to a pEp::String object in invalid state, and it must be initialized using
    // init(). Otherwise all(most) functions will throw.
    // init() can only be called once, will throw otherwise.
    // NON-owning mode, just does not free the string when it dies, owning mode does.
    // Thats the only difference.
    class String {
    public:
        String() = default;

        // Best to use this constructor, as the object is in a valid state when the wrapped
        // c_str (char*) is known
        String(bool take_ownership, char** c_str_pp)
        {
            init(take_ownership, c_str_pp);
        }

        explicit String(bool take_ownership, char** c_str_pp, const std::string& init_val)
        {
            init(take_ownership, c_str_pp, init_val);
        }

        ~String()
        {
            if (_is_owning_mode) {
                _free();
            }
        }

        void init(bool take_ownership, char** c_str_pp, const std::string& init_val)
        {
            init(take_ownership, c_str_pp);
            this->operator=(init_val);
        }

        void init(bool take_ownership, char** c_str_pp)
        {
            if (c_str_pp == nullptr) {
                throw Exception{ EXSTR("cant init on a nullptr") };
            }

            if (_is_initialized) {
                throw Exception{ EXSTR("double initialization") };
            }

            // init
            _c_str_pp = c_str_pp;
            _c_str_p = *_c_str_pp;
            _is_initialized = true;
            _is_owning_mode = take_ownership;
            pEpLogClass(to_string() + " - init " + (take_ownership ? "/taking ownership" : ""));
        }

        // make a copy
        String& operator=(const std::string& str)
        {
            pEpLogClass("Before: " + to_string() + " - new val: '" + pEp::Utils::clip(str, 30) + "'");
            if (_c_str_pp == nullptr) {
                throw Exception{ EXSTR("invalid state") };
            }

            // DEALLOCATION
            _free();

            // ALLOCATION
            if (str.empty()) {
                // if the new value is empty str, lets point to nothing
                *_c_str_pp = nullptr;
                _c_str_p = *_c_str_pp;
            } else {
                *_c_str_pp = pEp::alloc_str(str);
                _c_str_p = *_c_str_pp;
            }
            pEpLogClass("After:  " + to_string());
            return *this;
        }

        // return a copy of whatever c_str currently is (maybe created by us, maybe changed meanwhile)
        operator std::string() const
        {
            if (_c_str_pp == nullptr) {
                throw Exception{ EXSTR("invalid state") };
            }

            if (*_c_str_pp != nullptr) {
                return { *_c_str_pp };
            }
            return {};
        }

        char** data()
        {
            return _c_str_pp;
        }

        const char* c_data() const
        {
            if (_c_str_pp == nullptr) {
                throw Exception{ EXSTR("invalid state") };
            }
            return *_c_str_pp;
        }

        std::string to_string() const
        {
            if (_c_str_pp == nullptr) {
                throw Exception{ EXSTR("invalid state") };
            }

            std::string ret{ "[" + CXX::Inspect::all(_c_str_pp) + " / " +
                             CXX::Inspect::all(*_c_str_pp) + "]" };
            return ret;
        }

        static bool log_enabled;

    private:
        // TODO: this is dodgy, do we really need _c_str_pp AND _c_str_p???
        void _free()
        {
            // if the c_str points to a different address now, than the one we created
            if (*_c_str_pp != _c_str_p) {
                // a new string has been created, and we need to free it as well
                pEpLog("raw access string change detected");
                pEp::free(*_c_str_pp);
            } else {
                // WE ASSUME THAT:
                // if the char* has been replaced, it has been freed, as well
                if (_c_str_p != nullptr) {
                    pEp::free(_c_str_p);
                }
            }
        }

        bool _is_initialized{ false };
        bool _is_owning_mode{ false };
        char** _c_str_pp{ nullptr };
        char* _c_str_p{ nullptr };

        Adapter::pEpLog::pEpLogger logger{ "pEp::String", log_enabled };
        Adapter::pEpLog::pEpLogger& m4gic_logger_n4me = logger;

        class Exception : public std::runtime_error {
        public:
            explicit Exception(const std::string& msg) : std::runtime_error(msg) {}
        };
    };

    bool pEp::String::log_enabled{ true };

    std::ostream& operator<<(std::ostream& o, const pEp::String& pEpStr)
    {
        return o << std::string(pEpStr);
    }

    //---------------------------------------------------------------------------------------------

    // TOOD:
    // ctor not exception safe
    class Identity {
    public:
        Identity(
            const std::string& address = "",
            const std::string& username = "",
            const std::string& user_id = "",
            const std::string& fpr = "")
        {
            pEpLogClass("called");
            _wrappee = ::new_identity(nullptr, nullptr, nullptr, nullptr);

            // set the pEp::String wrapper underlying c_str
            this->address.init(true, &_wrappee->address, address);
            this->username.init(true, &_wrappee->username, username);
            this->user_id.init(true, &_wrappee->user_id, user_id);
            this->fpr.init(true, &_wrappee->fpr, fpr);
        }

        ~Identity()
        {
            _free();
        }


        pEp::String address{};
        pEp::String username{};
        pEp::String user_id{};
        pEp::String fpr{};

        operator ::pEp_identity*()
        {
            return _wrappee;
        }

        static bool log_enabled;

    private:
        void _free()
        {
            //            pEp::free(_wrappee);
        }

        ::pEp_identity* _wrappee{ nullptr };
        Adapter::pEpLog::pEpLogger logger{ "IdentWrappySP", log_enabled };
        Adapter::pEpLog::pEpLogger& m4gic_logger_n4me = logger;
    };

    bool Identity::log_enabled{ true };

} // namespace pEp


::PEP_SESSION session;

void test_getters(char** c_str_p, pEp::String& pstr, const std::string& expected)
{
    pEpLog("to_string(): " + pstr.to_string());
    // compare addresses
    pEpLog("addresses == c_str_p");
    assert(pstr.c_data() == *c_str_p);
    assert(pstr.data() == c_str_p);

    // compare values
    if (*c_str_p != nullptr) {
        pEpLog("operator std::string(): " + std::string(pstr));
        assert(std::string(pstr) == std::string(*c_str_p));
        assert(std::string(pstr) == expected);

        // will segfault with nullptr, and this is correct
        pEpLog("data(): " + std::string(*pstr.data()));
        assert(std::string(*pstr.data()) == std::string(*c_str_p));
        assert(std::string(*pstr.data()) == expected);

        pEpLog("c_data(): " + std::string(pstr.c_data()));
        assert(std::string(pstr.c_data()) == std::string(*c_str_p));
        assert(std::string(pstr.c_data()) == expected);
    } else {
        std::string tmp{ pstr };
        pEpLog("operator std::string(): " + tmp);
        assert(tmp.empty());
    }
}

void test_assign(char** c_str_p, pEp::String& pstr)
{
    {
        pEpLogH2("assign operator");
        std::string new_val{ "assign operator" };
        pstr = new_val;
        test_getters(c_str_p, pstr, new_val);
    }
    {
        pEpLogH2("raw c_str assign");
        std::string new_val{ "raw c_str assign" };
        free(*c_str_p);
        *c_str_p = strdup(new_val.c_str());
        test_getters(c_str_p, pstr, new_val);
    }
}

void test_getters(int* c_int_p, pEp::POD<int>& pint, int expected)
{
    pEpLog("to_string(): " + pint.to_string());
    // compare addresses
    pEpLog("addresses == c_int_p");
    assert(pint.c_data() == c_int_p);
    assert(pint.data() == c_int_p);

    // compare values
    if (c_int_p != nullptr) {
        pEpLog("operator int(): " + std::to_string(pint));
        assert(pint == *c_int_p);
        assert(pint == expected);

        // will segfault with nullptr, and this is correct
        pEpLog("data(): " + std::to_string(*pint.data()));
        assert(*pint.data() == *c_int_p);
        assert(*pint.data() == expected);

        pEpLog("c_data(): " + std::to_string(*pint.c_data()));
        assert(*pint.c_data() == *c_int_p);
        assert(*pint.c_data() == expected);
    }
}

void test_assign(int* c_int_p, pEp::POD<int>& pint)
{
    {
        pEpLogH2("assign operator");
        int new_val = 23;
        pint = new_val;
        test_getters(c_int_p, pint, new_val);
    }
    {
        pEpLogH2("raw c_str assign");
        int new_val = 23;
        *c_int_p = new_val;
        test_getters(c_int_p, pint, new_val);
    }
}


// We are testing wrappers for the c-datatypes:
// * integral e.g (int) here
// * enum
// * c-string
// * struct
// Those are all considered POD-types
extern "C" {
    typedef enum
    {
        ONE,
        TWO,
        THREE
    } Test_enum;

    typedef struct {
        int c_int;
        Test_enum c_enum;
        char* c_str;
    } Test_struct;
}

int main()
{
    // c-types are always POD
    // we need to handle pointer types and value types differently
    // pointer types need to be memory-managed (heap)
    // value types are being copied around (stack)
    static_assert(std::is_pod<int>::value && !std::is_pointer<int>::value, "not an integral");
    static_assert(
        std::is_pod<Test_enum>::value && !std::is_pointer<Test_enum>::value,
        "not an integral");
    static_assert(
        std::is_pod<Test_struct>::value && !std::is_pointer<Test_struct>::value,
        "not an integral");

    //    static_assert(std::is_pod<char*>::value && !std::is_pointer<char*>::value, "not an integral");

    //    pEp::Utils::readKey();
    pEp::Adapter::pEpLog::set_enabled(true);

    // POD
    if (1) {
        // VALID USAGE
        int init_val = 0;
        // new pEp::POD on int
        {
            pEpLogH1("new pEp::POD on int");
            int c_int = init_val;
            pEp::POD<int> pint(&c_int);
            test_getters(&c_int, pint, init_val);
            test_assign(&c_int, pint);
        }
    }

    // String
    //            pEp::String::log_enabled = false;
    if (0) {
        //TODO: Test non-owning mode

        // INVALID USAGE
        //    char* c_str_u;           // uninitialized == INVALID
        //    undefined behaviour, most likely "pointer being freed was not allocated"
        //    {
        //        char* c_str;
        //        pEp::String pstr(c_str);
        //    }
        //    char* c_str_s = "fdsfs"; // statically initialized == INVALID
        //    {
        //        char ca[4] = { 'p', 'E', 'p'};
        //        char* c_str = ca;
        //        pEp::String pstr(c_str);
        //    }

        // VALID USAGE
        // new pEp::String on char* pointing to NULL
        {
            pEpLogH1("new pEp::String on char* pointing to NULL");
            char* c_str = NULL; // nullptr

            pEp::String pstr(true, &c_str);
            test_getters(&c_str, pstr, "");
            test_assign(&c_str, pstr);
        }

        std::string init_val{ "initialized c string" };
        // new pEp::String on already initalized char*
        {
            pEpLogH1("new pEp::String on already initalized char*");
            char* c_str = strdup(init_val.c_str());

            pEp::String pstr(true, &c_str);
            test_getters(&c_str, pstr, init_val);
            test_assign(&c_str, pstr);
        }

        // initialize()
        {
            pEpLogH1("init()");
            pEp::String pstr{};

            char* c_str = strdup(init_val.c_str());
            //TODO: PITYASSERT_THROWS
            pstr.init(true, &c_str);
            test_getters(&c_str, pstr, init_val);
            test_assign(&c_str, pstr);
        }
    }

    if (0) {
        setenv("HOME", ".", 1);
        ::init(&session, nullptr, nullptr, nullptr);

        //                create identity
        pEp::Identity id1{ "wrong@entry.lol", "wrong", "23", "INVA_FPR" };

        pEpLog(id1);
        id1.username = "alice";
        id1.address = "alice@peptest.org";

        pEpLog(id1.address);
        pEpLog(id1.username);
        ::myself(session, id1);
        pEpLog(id1);

        pEp::Identity id2{ "bob" };
        ::update_identity(session, id2);
        pEpLog(id2);
    }
}