/*
    Copyright 2005-2010 Intel Corporation.  All Rights Reserved.

    This file is part of Threading Building Blocks.

    Threading Building Blocks is free software; you can redistribute it
    and/or modify it under the terms of the GNU General Public License
    version 2 as published by the Free Software Foundation.

    Threading Building Blocks is distributed in the hope that it will be
    useful, but WITHOUT ANY WARRANTY; without even the implied warranty
    of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Threading Building Blocks; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    As a special exception, you may use this file as part of a free software
    library without restriction.  Specifically, if other files instantiate
    templates or use macros or inline functions from this file, or you compile
    this file and link it with other files to produce an executable, this
    file does not by itself cause the resulting executable to be covered by
    the GNU General Public License.  This exception does not however
    invalidate any other reasons why the executable file might be covered by
    the GNU General Public License.
*/

// Uncomment next line to disable shared memory features if you have not libXext
// (http://www.xfree86.org/current/mit-shm.html)
//#define X_NOSHMEM

#include "video.h"
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/keysym.h>
#include <sys/time.h>
#include <signal.h>
#include <pthread.h>

#ifndef X_NOSHMEM
#include <errno.h>
#include <X11/extensions/XShm.h>
#include <sys/ipc.h>
#include <sys/shm.h>

static XShmSegmentInfo shmseginfo;
static Pixmap pixmap = 0;
#endif
static char *display_name = NULL;
static Display *dpy = NULL;
static Screen *scrn;
static Visual *vis;
static Colormap cmap;
static GC gc;
static Window win, rootW;
static int dispdepth = 0;
static XGCValues xgcv;
static XImage *ximage;
static int x_error = 0;
static int vidtype = 3;
static int g_sizex, g_sizey;
static video *g_video = 0;
static unsigned int *g_pImg = 0;
static int g_fps = 0;
struct timeval g_time;
static pthread_mutex_t g_mutex = PTHREAD_MUTEX_INITIALIZER;
Atom _XA_WM_DELETE_WINDOW = 0;// like in Xatom.h

///////////////////////////////////////////// public methods of video class ///////////////////////

video::video()
{
    assert(g_video == 0);
    g_video = this; title = "Video"; calc_fps = running = false; updating = true;
}

inline void mask2bits(unsigned int mask, unsigned int &save, char &shift)
{
    save  = mask; if(!mask) { shift = dispdepth/3; return; }
    shift = 0; while(!(mask&1)) ++shift, mask >>= 1;
    int bits = 0; while(mask&1) ++bits,  mask >>= 1;
    shift += bits - 8;
}

int xerr_handler(Display*, XErrorEvent *error)
{
    x_error = error->error_code;
    if(g_video) g_video->running = false;
    return 0;
}

bool video::init_window(int xsize, int ysize)
{
    { //enclose local variables before fail label
    g_sizex = xsize; g_sizey = ysize;

    // Open the display
    if (!dpy) {
        dpy = XOpenDisplay(display_name);
        if (!dpy) {
            fprintf(stderr, "Can't open X11 display %s\n", XDisplayName(display_name));
            goto fail;
        }
    }
    int theScreen = DefaultScreen(dpy);
    scrn = ScreenOfDisplay(dpy, theScreen);
    dispdepth = DefaultDepth(dpy, theScreen);
    XVisualInfo vinfo;
    if (!( (dispdepth >= 15 && dispdepth <= 32 && XMatchVisualInfo(dpy, theScreen, dispdepth, TrueColor, &vinfo) )
        || XMatchVisualInfo(dpy, theScreen, 24, TrueColor, &vinfo)
        || XMatchVisualInfo(dpy, theScreen, 32, TrueColor, &vinfo)
        || XMatchVisualInfo(dpy, theScreen, 16, TrueColor, &vinfo)
        || XMatchVisualInfo(dpy, theScreen, 15, TrueColor, &vinfo)
        )) {
        fprintf(stderr, "Display has no appropriate True Color visual\n");
        goto fail;
    }
    vis = vinfo.visual;
    depth = dispdepth = vinfo.depth;
    mask2bits(vinfo.red_mask, red_mask, red_shift);
    mask2bits(vinfo.green_mask, green_mask, green_shift);
    mask2bits(vinfo.blue_mask, blue_mask, blue_shift);
    rootW = RootWindow(dpy, theScreen);
    cmap = XCreateColormap(dpy, rootW, vis, AllocNone);
    XSetWindowAttributes attrs;
    attrs.backing_store = Always;
    attrs.colormap = cmap;
    attrs.event_mask = StructureNotifyMask|KeyPressMask|ButtonPressMask|ButtonReleaseMask;
    attrs.background_pixel = BlackPixelOfScreen(scrn);
    attrs.border_pixel = WhitePixelOfScreen(scrn);
    win = XCreateWindow(dpy, rootW,
        0, 0, xsize, ysize, 2,
        dispdepth, InputOutput, vis,
        CWBackingStore | CWColormap | CWEventMask |
        CWBackPixel | CWBorderPixel,
        &attrs);
    if(!win) {
        fprintf(stderr, "Can't create the window\n");
        goto fail;
    }
    XSizeHints sh;
    sh.flags = PSize | PMinSize | PMaxSize;
    sh.width = sh.min_width = sh.max_width = xsize;
    sh.height = sh.min_height = sh.max_height = ysize;
    XSetStandardProperties( dpy, win, g_video->title, g_video->title, None, NULL, 0, &sh );
    _XA_WM_DELETE_WINDOW = XInternAtom(dpy, "WM_DELETE_WINDOW", false);
    XSetWMProtocols(dpy, win, &_XA_WM_DELETE_WINDOW, 1);
    gc = XCreateGC(dpy, win, 0L, &xgcv);
    XMapRaised(dpy, win);
    XFlush(dpy);
#ifdef X_FULLSYNC
	XSynchronize(dpy, true);
#endif
    XSetErrorHandler(xerr_handler);

    int imgbytes = xsize*ysize*(dispdepth<=16?2:4);
    const char *vidstr;
#ifndef X_NOSHMEM
    int major, minor, pixmaps;
    if(XShmQueryExtension(dpy) &&
       XShmQueryVersion(dpy, &major, &minor, &pixmaps))
    { // Shared memory
        shmseginfo.shmid = shmget(IPC_PRIVATE, imgbytes, IPC_CREAT|0777);
        if(shmseginfo.shmid < 0) {
            fprintf(stderr, "Warning: Can't get shared memory: %s\n", strerror(errno));
            goto generic;
        }
        g_pImg = (unsigned int*)(shmseginfo.shmaddr = (char*)shmat(shmseginfo.shmid, 0, 0));
        if(g_pImg == (unsigned int*)-1) {
            fprintf(stderr, "Warning: Can't attach to shared memory: %s\n", strerror(errno));
            shmctl(shmseginfo.shmid, IPC_RMID, NULL);
            goto generic;
        }
        shmseginfo.readOnly = false;
        if(!XShmAttach(dpy, &shmseginfo) || x_error) {
            char err[256]; XGetErrorText(dpy, x_error, err, 255);
            fprintf(stderr, "Warning: Can't attach shared memory to display: %s (%d)\n", err, x_error);
            shmdt(shmseginfo.shmaddr); shmctl(shmseginfo.shmid, IPC_RMID, NULL);
            goto generic;
        }

#ifndef X_NOSHMPIX
        if(pixmaps && XShmPixmapFormat(dpy) == ZPixmap)
        { // Pixmaps
            vidtype = 2; vidstr = "X11 shared memory pixmap";
            pixmap = XShmCreatePixmap(dpy, win, (char*)g_pImg, &shmseginfo, xsize, ysize, dispdepth);
            XSetWindowBackgroundPixmap(dpy, win, pixmap);
        } else
#endif//!X_NOSHMPIX
        { // Standart
            vidtype = 1; vidstr = "X11 shared memory";
            ximage = XShmCreateImage(dpy, vis, dispdepth,
                ZPixmap, 0, &shmseginfo, xsize, ysize);
            if(!ximage) {
                fprintf(stderr, "Can't create the shared image\n");
                goto fail;
            }
            assert(ximage->bytes_per_line == xsize*(dispdepth<=16?2:4));
            ximage->data = shmseginfo.shmaddr;
        }
    } else
#endif
    {
generic:
        vidtype = 0; vidstr = "generic X11";
        g_pImg = new unsigned int[imgbytes/sizeof(int)];
        ximage = XCreateImage(dpy, vis, dispdepth, ZPixmap, 0, (char*)g_pImg, xsize, ysize, 32, imgbytes/ysize);
        if(!ximage) {
            fprintf(stderr, "Can't create the image\n");
            goto fail;
        }
    }
    printf("Note: using %s with %s visual for %d-bit color depth\n", vidstr, vis==DefaultVisual(dpy, theScreen)?"default":"non-default", dispdepth);
    running = true;
    return true;
    } // end of enclosing local varables
fail:
    terminate(); init_console();
    return false;
}

bool video::init_console()
{
    if(!g_pImg && g_sizex && g_sizey) {
        dispdepth = 24; red_shift = 16; vidtype = 3; // fake video
        g_pImg = new unsigned int[g_sizex*g_sizey];
        running = true;
    }
    return true;
}

void video::terminate()
{
    running = false;
    if(dpy) {
        vidtype = 3; // stop video
        if(threaded) { pthread_mutex_lock(&g_mutex); pthread_mutex_unlock(&g_mutex); }
        if(ximage) { XDestroyImage(ximage); ximage = 0; g_pImg = 0; } // it frees g_pImg for vidtype == 0
#ifndef X_NOSHMEM
        if(pixmap) XFreePixmap(dpy, pixmap);
        if(shmseginfo.shmaddr) { XShmDetach(dpy, &shmseginfo); shmdt(shmseginfo.shmaddr); g_pImg = 0; }
        if(shmseginfo.shmid >= 0) shmctl(shmseginfo.shmid, IPC_RMID, NULL);
#endif
        if(gc) XFreeGC(dpy, gc);
        if(win) XDestroyWindow(dpy, win);
        XCloseDisplay(dpy); dpy = 0;
    }
    if(g_pImg) { delete[] g_pImg; g_pImg = 0; } // if was allocated for console mode
}

video::~video()
{
    if(g_video) terminate();
    g_video = 0;
}

//! Do standard event loop
void video::main_loop()
{
    struct timezone tz; gettimeofday(&g_time, &tz);
    on_process();
}

//! Check for pending events once
bool video::next_frame()
{
	if(!running) return false;
    //! try acquire mutex if threaded code, returns on failure
    if(vidtype == 3 || threaded && pthread_mutex_trylock(&g_mutex))
        return running;
    //! Refresh screen picture
    g_fps++;
#ifndef X_NOSHMPIX
    if(vidtype == 2 && updating) XClearWindow(dpy, win);
#endif
    while( XPending(dpy) ) {
        XEvent report; XNextEvent(dpy, &report);
        switch( report.type ) {
            case ClientMessage:
                if(report.xclient.format != 32 || report.xclient.data.l[0] != _XA_WM_DELETE_WINDOW) break;
            case DestroyNotify:
                running = false;
            case KeyPress:
                on_key( XLookupKeysym(&report.xkey, 0) ); break;
            case ButtonPress:
                on_mouse( report.xbutton.x, report.xbutton.y, report.xbutton.button ); break;
            case ButtonRelease:
                on_mouse( report.xbutton.x, report.xbutton.y, -report.xbutton.button ); break;
        }
    }
    struct timezone tz; struct timeval now_time; gettimeofday(&now_time, &tz);
    double sec = (now_time.tv_sec+1.0*now_time.tv_usec/1000000.0) - (g_time.tv_sec+1.0*g_time.tv_usec/1000000.0);
    if(sec > 1) {
        memcpy(&g_time, &now_time, sizeof(g_time));
        if(calc_fps) {
            double fps = g_fps; g_fps = 0;
            char buffer[256]; snprintf(buffer, 256, "%s%s: %d fps", title, updating?"":" (no updating)", int(fps/sec));
            XStoreName(dpy, win, buffer);
        }
#ifndef X_FULLSYNC
        XSync(dpy, false); // It is often better then using XSynchronize(dpy, true)
#endif//X_FULLSYNC
  	}
  	if(threaded) pthread_mutex_unlock(&g_mutex);
    return true;
}

//! Change window title
void video::show_title()
{
    if(vidtype < 3)
        XStoreName(dpy, win, title);
}

drawing_area::drawing_area(int x, int y, int sizex, int sizey)
    : start_x(x), start_y(y), size_x(sizex), size_y(sizey), pixel_depth(dispdepth),
    base_index(y*g_sizex + x), max_index(g_sizex*g_sizey), index_stride(g_sizex), ptr32(g_pImg)
{
    assert(x < g_sizex); assert(y < g_sizey);
    assert(x+sizex <= g_sizex); assert(y+sizey <= g_sizey);

    index = base_index; // current index
}

drawing_area::~drawing_area()
{
    if(!g_video->updating) return;
#ifndef X_NOSHMEM
    switch(vidtype) {
    case 0:
#endif
        pthread_mutex_lock(&g_mutex);
        if(vidtype == 0) XPutImage(dpy, win, gc, ximage, start_x, start_y, start_x, start_y, size_x, size_y);
        pthread_mutex_unlock(&g_mutex);
#ifndef X_NOSHMEM
        break;
    case 1:
        pthread_mutex_lock(&g_mutex);
        if(vidtype == 1) XShmPutImage(dpy, win, gc, ximage, start_x, start_y, start_x, start_y, size_x, size_y, false);
        pthread_mutex_unlock(&g_mutex);
        break;
    /*case 2: make it in next_frame(); break;*/
    }
#endif
}