#include <malloc.h>
#include <chrono>
#include <stdint.h>
#include <string.h>
#ifdef _WIN32
#include <windows.h>
#include <filesystem>
#else
#include <unistd.h>
#include <spawn.h>
#endif
#include <fcntl.h>
#include "rktwebview.h"
#include "rkt_protocol.h"
#include "shmqueue.h"
#include "json.h"
#include "utils.h"

#define SHM_SIZE (10 * 1024 * 1024)     // 10MB
#define COMMAND_SLOT        1
#define COMMAND_RESULT_SLOT 2
#define EVENT_SLOT          3

//#define DEBUG

/////////////////////////////////////////////////////////////////////
// Utility functions
/////////////////////////////////////////////////////////////////////

typedef struct {
    std::string name;
    size_t      shm_size;
    Shm *shm;
    ShmQueue *command_queue;
    ShmQueue *command_result_queue;
    ShmQueue *event_queue;
#ifdef _WIN32
    HANDLE rkt_webview_prg_pid;
#else
    pid_t rkt_webview_prg_pid;
#endif

    bool rkt_webview_prg_started;
    bool valid;
} Handle_t;

Handle_t *handler = nullptr;

static bool fileExists(const char *filename) {
#ifdef _WIN32
    DWORD dwAttrib = GetFileAttributes(filename);
    return (dwAttrib != INVALID_FILE_ATTRIBUTES &&
            !(dwAttrib & FILE_ATTRIBUTE_DIRECTORY));
#else
    return access(filename, X_OK) != -1;
#endif
}

uint64_t current_ms() {
    using namespace std::chrono;
    return duration_cast<milliseconds>(system_clock::now().time_since_epoch()).count();
}

bool runRktWebview(Handle_t *handler)
{
    char *rkt_webview_prg_path = getenv("RKT_WEBVIEW_PRG");
    if (rkt_webview_prg_path == nullptr) {
        fprintf(stderr, "RKT_WEBVIEW_PRG environment variable not set, cannot start webview program\n");fflush(stderr);
        return false;
    }
    if (!fileExists(rkt_webview_prg_path)) {
        fprintf(stderr, "%s does not exist or is not executable\n", rkt_webview_prg_path);fflush(stderr);
        return false;
    }

    std::string path = basedir(rkt_webview_prg_path);

    char shm_size_str[30];
    char command_slot[10];
    char command_result_slot[10];
    char event_slot[10];

    sprintf(shm_size_str, "%d", static_cast<int>(handler->shm_size));
    sprintf(command_slot, "%d", COMMAND_SLOT);
    sprintf(command_result_slot, "%d", COMMAND_RESULT_SLOT);
    sprintf(event_slot, "%d", EVENT_SLOT);

    // run rktwebview_prg using the environment variable RKT_WEBVIEW_PRG
#ifdef _WIN32

    //STARTUPINFO si;
    //PROCESS_INFORMATION pi;
    //ZeroMemory( &si, sizeof(si) );
    //si.cb = sizeof(si);
    //ZeroMemory( &pi, sizeof(pi) );

    std::string cmdargs = std::string("") + handler->name + " " + shm_size_str + " " + command_slot + " " + command_result_slot + " " + event_slot;
    std::string exe = std::string(rkt_webview_prg_path);

    const char *td = getenv("TEMP");
    if (td == nullptr) { td = "C:\\"; }
    std::string tmpdir = td;
    std::string logfile = tmpdir + "\\" + "rktwebview.log"; //handler->name + ".log";
    std::string errfile = tmpdir + "\\" + "rktwebview.err";
    std::string redirect = " ^>" + logfile + " 2^>" + errfile;
    std::string cmdline = "start /b \"\" cmd /c \"" + exe + " " + cmdargs + " " + /*redirect*/ + "\"" + redirect;

    char *cmdline_str = const_cast<char *>(cmdline.c_str());

    auto cwd = std::filesystem::current_path();
    std::filesystem::current_path(path);
    int r = system(cmdline_str);
    std::filesystem::current_path(cwd);

        //CreateProcessA(NULL, cmdline_str, NULL, NULL, FALSE, NORMAL_PRIORITY_CLASS, NULL, path.c_str(), &si, &pi);
    handler->rkt_webview_prg_pid = 0;
    if (r != 0) {
        fprintf(stderr, "Cannot create process '%s' (error = %ld)\n", cmdline_str, GetLastError());fflush(stderr);
    }
    return (r == 0);
#else
    char *argv[] = { rkt_webview_prg_path, const_cast<char *>(handler->name.c_str()), shm_size_str, command_slot, command_result_slot, event_slot, nullptr };

    int r = posix_spawn(&handler->rkt_webview_prg_pid, rkt_webview_prg_path, nullptr, nullptr, argv, environ);

    return (r == 0);
#endif
}

/////////////////////////////////////////////////////////////////////
// Main C Interface
/////////////////////////////////////////////////////////////////////


void rkt_webview_cleanup()
{
    if (handler != nullptr) {
        // Does nothing.
        // See QTBUG-145033
        // QtWebEngine cannot be started as part of QApplication more than once in an application run.
        // So we would need to cleanup at exit of racket/drracket.
        // Cleaning up when exiting the current custodian is not enough.

        /*
        QApplication *app = handler->app();
        if (app != nullptr) {
            // testing with #:custodian (current-custodian)
            QTimer t;
            QObject::connect(&t, &QTimer::timeout, app, [app]() {
                fprintf(stderr, "Quitting\n");
                app->quit();
            });
            t.setSingleShot(true);
            t.start(250);
            fprintf(stderr, "Executing app\n");
            app->exec();
            fprintf(stderr, "App exited\n");
            delete handler;
            handler = nullptr;
        }
        */

        if (handler->valid) {
            fprintf(stderr, "Sending quit message\n");fflush(stderr);
            handler->command_queue->enqueue(CMD_QUIT);
            fprintf(stderr, "Message sent\n");fflush(stderr);
            bool stopped = false;
            while(!stopped) {
                int cmd;
                std::string s;
                fprintf(stderr, "Getting result of quit message\n");fflush(stderr);
                handler->command_result_queue->dequeue(cmd, s, true);
                fprintf(stderr, "got %d\n", cmd);fflush(stderr);
                if (cmd == RESULT_QUIT) {
                    stopped = true;
                }
            }
        }

        delete handler->event_queue;
        delete handler->command_result_queue;
        delete handler->command_queue;
        delete handler->shm;
        delete handler;
        handler = nullptr;
    }
}

void rkt_webview_init()
{
    if (handler == nullptr) {
        // Create shared memory and communication queues

        char buf[1024];
#ifdef DEBUG
        sprintf(buf, "rktwebview-dbg");
#else
#ifdef _WIN32
        DWORD p = GetCurrentProcessId();
        sprintf(buf, "rktwebview-%ld", p);
#else
        pid_t p = getpid();
        sprintf(buf, "rktwebview-%x", p);
#endif
#endif

        handler = new Handle_t;
        handler->valid = true;
        handler->name = buf;

        handler->shm_size = SHM_SIZE;
        handler->shm = new Shm(handler->name.data(), handler->shm_size, true);
        if (!handler->shm->isValid()) { handler->valid = false; }
        handler->command_queue = new ShmQueue(handler->shm, COMMAND_SLOT, true);
        handler->command_result_queue = new ShmQueue(handler->shm, COMMAND_RESULT_SLOT, true);
        handler->event_queue = new ShmQueue(handler->shm, EVENT_SLOT, true);

        // Start rktwebview_prg application with the right information
#ifndef DEBUG
        handler->rkt_webview_prg_started = runRktWebview(handler);
        if (!handler->rkt_webview_prg_started) { handler->valid = false; }
#endif
    }
}

bool rkt_webview_valid(rktwebview_t wv)
{
    rkt_webview_init();
    if (handler != nullptr && handler->valid) {
        handler->command_queue->enqueue(CMD_HANDLE_IS_VALID);
        int result;
        std::string json_result;
        handler->command_result_queue->dequeue(result, json_result, true);
        return result == 0;
    } else {
        return false;
    }
}

static inline bool validHandle()
{
    return (handler != nullptr) && handler->valid;
}

#define FAIL_HANDLE if (!validHandle()) { return result_t::invalid_handle; }
#define FAIL_CONTEXT if (!validHandle()) { return 0; }
#define FAIL_WV if (!validHandle()) { return 0; }
#define NOOP_HANDLE if (!validHandle()) { return; }
#define FAIL_CALL_JS if (!validHandle()) { return nullptr; }

rkt_wv_context_t rkt_webview_new_context(const char *boilerplate_js, const char *optional_server_cert_pem)
{
    rkt_webview_init();
    FAIL_CONTEXT

    JSON j;

    std::string bpj(boilerplate_js);
    bool has_pem_cert = optional_server_cert_pem != nullptr;
    std::string osc(has_pem_cert ? optional_server_cert_pem : "");

    j["boilerplate_js"] = bpj;
    j["has_pem_cert"] = has_pem_cert;
    j["pem_cert"] = osc;

    handler->command_queue->enqueue(CMD_CONTEXT_NEW, j.dump());

    int result;
    std::string json_result;
    handler->command_result_queue->dequeue(result, json_result, true);
    return result;
}

int rkt_webview_create(rkt_wv_context_t context, rktwebview_t parent)
{
    rkt_webview_init();
    FAIL_WV

    JSON j;
    j["context"] = context;
    j["parent"] = parent;

    handler->command_queue->enqueue(CMD_CREATE_WV, j.dump());

    int result;
    std::string json_result;
    handler->command_result_queue->dequeue(result, json_result, true);

    return result;
}

void rkt_webview_close(rktwebview_t wv)
{
    rkt_webview_init();
    NOOP_HANDLE

    JSON j;
    j["wv"] = wv;
    handler->command_queue->enqueue(CMD_CLOSE_WV, j.dump());
}

#define CMDRES4(cmd, wv, key, val, key2, val2, key3, val3, key4, val4) \
    rkt_webview_init(); \
    FAIL_HANDLE \
    JSON j; \
    j["wv"] = wv; \
    j[key] = val; \
    j[key2] = val2; \
    j[key3] = val3; \
    j[key4] = val4; \
    handler->command_queue->enqueue(cmd, j.dump()); \
    int result; \
    std::string json_result; \
    handler->command_result_queue->dequeue(result, json_result, true); \
    result_t r = static_cast<result_t>(result); \
    return r;

#define CMDRES3(cmd, wv, key, val, key2, val2, key3, val3) \
    CMDRES4(cmd, wv, key, val, key2, val2, key3, val3, "nil3", "none")

#define CMDRES2(cmd, wv, key, val, key2, val2) \
    CMDRES3(cmd, wv, key, val, key2, val2, "nil2", "none")

#define CMDRES(cmd, wv, key, val) \
    CMDRES2(cmd, wv, key, val, "nil1", "none")

#define CMDRES0(cmd, wv) \
    CMDRES(cmd, wv, "nil0", "none")

result_t rkt_webview_set_url(rktwebview_t wv, const char *url)
{
    CMDRES(CMD_SET_URL, wv, "url", url)
}

result_t rkt_webview_set_html(rktwebview_t wv, const char *html)
{
    CMDRES(CMD_SET_HTML, wv, "html", html)
}


result_t rkt_webview_run_js(rktwebview_t wv, const char *js)
{
    CMDRES(CMD_RUN_JS, wv, "js", js)
}

rkt_data_t *rkt_webview_call_js(rktwebview_t wv, const char *js)
{
    rkt_webview_init();
    FAIL_CALL_JS

    JSON j;
    j["wv"] = wv;
    j["js"] = std::string(js);
    handler->command_queue->enqueue(CMD_CALL_JS, j.dump());

    int result;
    std::string json_result;
    handler->command_result_queue->dequeue(result, json_result, true);

    rkt_data_t *r = new rkt_data_t();
    r->kind = rkt_data_kind_t::js_result;
    r->data.js_result.result = static_cast<result_t>(result);
    r->data.js_result.value = strdup(json_result.c_str());

    return r;
}

result_t rkt_webview_open_devtools(rktwebview_t wv)
{
    CMDRES(CMD_OPEN_DEVTOOLS, wv, "nil", "none")
}

/*
void rkt_webview_process_events(int for_ms)
{
    rkt_webview_init();

    uint64_t start_ms = current_ms();
    uint64_t end_ms = start_ms + for_ms;

    while (current_ms() < end_ms) {
        QThread::usleep(500); // sleep 0.5 ms
        handler->doEvents();
    }
}
*/

result_t rkt_webview_move(rktwebview_t wv, int x, int y)
{
    CMDRES2(CMD_MOVE, wv, "x", x, "y", y)
}


result_t rkt_webview_resize(rktwebview_t wv, int width, int height)
{
    CMDRES2(CMD_RESIZE, wv, "w", width, "h", height)
}


result_t rkt_webview_hide(rktwebview_t w)
{
    CMDRES0(CMD_HIDE, w)
}

result_t rkt_webview_show(rktwebview_t w)
{
    CMDRES0(CMD_SHOW, w)
}

result_t rkt_webview_present(rktwebview_t w)
{
    CMDRES0(CMD_PRESENT, w)
}

result_t rkt_webview_maximize(rktwebview_t w)
{
    CMDRES0(CMD_MAXIMIZE, w)
}

result_t rkt_webview_minimize(rktwebview_t w)
{
    CMDRES0(CMD_MINIMIZE, w)
}

result_t rkt_webview_show_normal(rktwebview_t w)
{
    CMDRES0(CMD_SHOW_NORMAL, w)
}

window_state_t rkt_webview_window_state(rktwebview_t w)
{
    auto f = [w]() {
        CMDRES0(CMD_WINDOW_STATE, w)
    };
    int r = f();
    return static_cast<window_state_t>(r);
}

result_t rkt_webview_set_title(rktwebview_t wv, const char *title)
{
    CMDRES(CMD_SET_TITLE, wv, "title", title)
}

result_t rkt_webview_choose_dir(rktwebview_t w, const char *title, const char *base_dir)
{
    CMDRES2(CMD_CHOOSE_DIR, w, "title", title, "base_dir", base_dir)
}

result_t rkt_webview_file_open(rktwebview_t w, const char *title, const char *base_dir, const char *permitted_exts)
{
    CMDRES3(CMD_FILE_OPEN, w, "title", title, "base_dir", base_dir, "permitted_exts", permitted_exts)
}

result_t rkt_webview_file_save(rktwebview_t w, const char *title, const char *base_dir, const char *permitted_exts)
{
    CMDRES3(CMD_FILE_SAVE, w, "title", title, "base_dir", base_dir, "permitted_exts", permitted_exts)
}

void rkt_webview_set_ou_token(rktwebview_t wv, const char *token)
{
    rkt_webview_init();
    NOOP_HANDLE

    JSON j;
    j["wv"] = wv;
    j["token"] = std::string(token);

    handler->command_queue->enqueue(CMD_SET_OU_TOKEN, j.dump());
}

void rkt_webview_free_data(rkt_data_t *d)
{
    if (d == nullptr) { return; }

    if (d->kind == version) {
        free(d);
    } else if (d->kind == event) {
        free(d->data.event.event);
        free(d);
    } else if (d->kind == js_result) {
        free(d->data.js_result.value);
        free(d);
    } else {
        fprintf(stderr, "UNEXPECTED: data kind %d cannot be freed\n", d->kind);fflush(stderr);
    }
}

rkt_data_t *rkt_webview_version()
{
    rkt_data_t *d = static_cast<rkt_data_t *>(malloc(sizeof(rkt_data_t)));
    d->kind = version;
    d->data.version.api_major = RKT_WEBVIEW_API_MAJOR;
    d->data.version.api_minor = RKT_WEBVIEW_API_MINOR;
    d->data.version.api_patch = RKT_WEBVIEW_API_PATCH;
    return d;
}

result_t rkt_webview_message_box(rktwebview_t w, const char *title, const char *message, const char *submessage, rkt_messagetype_t type)
{
    CMDRES4(CMD_MSG_BOX, w, "title", title, "message", message, "submessage", submessage, "type", static_cast<int>(type))
}

int rkt_webview_events_waiting()
{
    return handler->event_queue->depth();
}

rkt_data_t *rkt_webview_get_event()
{
    //fprintf(stderr, "rkt_webview_get_event\n");
    int wv;
    std::string data;
    if (handler->event_queue->dequeue(wv, data, false)) {
        //fprintf(stderr, "got event %d %s\n", wv, data.c_str());
        rkt_data_t *d = reinterpret_cast<rkt_data_t *>(malloc(sizeof(rkt_data_t)));
        d->kind = rkt_data_kind_t::event;

        size_t ds = data.size();
        d->data.event.event = reinterpret_cast<char *>(malloc(ds + 1));
        memcpy(d->data.event.event, data.c_str(), ds);
        d->data.event.event[ds] = '\0';
        d->data.event.wv = wv;
        //fprintf(stderr, "event: %d - '%s'\n", d->data.event.wv, d->data.event.event);fflush(stderr);
        return d;
    } else {
        return nullptr;
    }
}

void rkt_webview_env(const char *env_cmds[])
{
    int i;
    for(i = 0; env_cmds[i] != nullptr && strcmp(env_cmds[i], "") != 0; i++) {
#ifdef WIN32
        _putenv(env_cmds[i]);
#else
        putenv(env_cmds[i]);
#endif
    }
}