// Released under the MIT license. X11 backend by Duuqnd.
// See LICENSE.txt for details.

#include "../Misc.h"

#include "../Rendering.h"
#include "../../Attributes.h"

#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>
#include <cstring>
#include <sys/time.h>

#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/keysym.h>

static bool keyboardState[BACKEND_KEYBOARD_TOTAL];
Display* xDisplay;
Visual* xVisual;
static XVisualInfo xvisinfo;
static unsigned long startTime;

bool Backend_Init(void (*drag_and_drop_callback)(const char *path), void (*window_focus_callback)(bool focus)) {
    // we're ignoring the hell out of focus and drag & drop
    xDisplay = XOpenDisplay(NULL);
    //XMatchVisualInfo(xDisplay, DefaultScreen(xDisplay), 24, DirectColor, &xvisinfo);
    //xVisual = xvisinfo.visual;

    struct timeval time; // time.tv_usec is microseconds
    gettimeofday(&time, NULL);
    startTime = (time.tv_sec * 1000) + (time.tv_usec / 1000);

    return true;
}

void Backend_Deinit(void) {
    XCloseDisplay(xDisplay);
}

void Backend_PostWindowCreation(void) {}

bool Backend_GetPaths(std::string *module_path, std::string *data_path) {
    return false; // I assume this means "do it yourself, lazy"
}

void Backend_HideMouse(void) {}

void Backend_SetWindowIcon(const unsigned char *rgb_pixels, size_t width, size_t height) {
    // Oh we'll want this for sure!
}

void Backend_SetCursor(const unsigned char *rgb_pixels, size_t width, size_t height) {}

void Backend_EnableDragAndDrop(void) {}

#define DOKEY(keych, keymac) { if(keysym == keych) keyboardState[keymac] = press; }

static void DoKeys(KeySym keysym, bool press) {
    // X keysyms are case sensitive. Isn't it great?!
    DOKEY(XK_z, BACKEND_KEYBOARD_Z);
    DOKEY(XK_x, BACKEND_KEYBOARD_X);
    DOKEY(XK_Z, BACKEND_KEYBOARD_Z);
    DOKEY(XK_X, BACKEND_KEYBOARD_X);
    DOKEY(XK_a, BACKEND_KEYBOARD_A);
    DOKEY(XK_s, BACKEND_KEYBOARD_S);
    DOKEY(XK_A, BACKEND_KEYBOARD_A);
    DOKEY(XK_S, BACKEND_KEYBOARD_S);

    DOKEY(XK_q, BACKEND_KEYBOARD_Q);
    DOKEY(XK_w, BACKEND_KEYBOARD_W);
    DOKEY(XK_Q, BACKEND_KEYBOARD_Q);
    DOKEY(XK_W, BACKEND_KEYBOARD_W);

    DOKEY(XK_Escape, BACKEND_KEYBOARD_ESCAPE);
    DOKEY(XK_F1, BACKEND_KEYBOARD_F1);
    DOKEY(XK_F2, BACKEND_KEYBOARD_F2);
    
    DOKEY(XK_Left, BACKEND_KEYBOARD_LEFT);
    DOKEY(XK_Right, BACKEND_KEYBOARD_RIGHT);
    DOKEY(XK_Up, BACKEND_KEYBOARD_UP);
    DOKEY(XK_Down, BACKEND_KEYBOARD_DOWN);
}

bool Backend_SystemTask(bool active) {
    if(!active) {
        return false;
    }

    XEvent e;
    while(XPending(xDisplay) > 0) {
        XNextEvent(xDisplay, &e);
        if(e.type == KeyPress) {
            KeySym keysym = XLookupKeysym((XKeyEvent*)&e, 0);
            if(keysym == XK_Insert) {
                return false;
            }
            DoKeys(keysym, true);
        }
        if(e.type == KeyRelease) {
            KeySym keysym = XLookupKeysym((XKeyEvent*)&e, 0);
            DoKeys(keysym, false);
        }
    }

    return true;
}

void Backend_GetKeyboardState(bool *out_keyboard_state) {
    memcpy(out_keyboard_state, keyboardState, sizeof(keyboardState));
}

ATTRIBUTE_FORMAT_PRINTF(1, 2) void Backend_PrintError(const char *format, ...) {
	va_list argumentList;
	va_start(argumentList, format);
	fputs("ERROR: ", stderr);
	vfprintf(stderr, format, argumentList);
	fputc('\n', stderr);
	va_end(argumentList);
}

ATTRIBUTE_FORMAT_PRINTF(1, 2) void Backend_PrintInfo(const char *format, ...) {
	va_list argumentList;
	va_start(argumentList, format);
	fputs("INFO: ", stdout);
	vfprintf(stdout, format, argumentList);
	fputc('\n', stdout);
	va_end(argumentList);
}

void Backend_ShowMessageBox(const char* title, const char* message) {
    printf("ShowMessageBox: %s - %s\n", title, message);
}

unsigned long Backend_GetTicks(void) {
    struct timeval time; // time.tv_usec is microseconds
    gettimeofday(&time, NULL);
    unsigned long ticktime = ((time.tv_sec * 1000) + (time.tv_usec / 1000)) - startTime;
    return ticktime;
}

void Backend_Delay(unsigned int ticks) {
    usleep(ticks * 1000);
}