var promise = require('promise');
var PPosition = 4;
var PSize = 8;
var _NET_WM_STATE_REMOVE = 0;    // remove/unset property
var _NET_WM_STATE_ADD = 1;    // add/set property
var _NET_WM_STATE_TOGGLE = 2;    // toggle property
var SubstructureRedirectMask = (1 << 20);
var SubstructureNotifyMask = (1 << 19);

function getLibInfo(libname)
{
    if (process.platform != 'linux') { throw ('Only supported on linux'); }

    var child = require('child_process').execFile('/bin/sh', ['sh']);
    child.stdout.str = '';
    child.stdout.on('data', function (chunk) { this.str += chunk.toString(); });
    child.stdin.write("ldconfig -p | grep '" + libname + ".so.'\nexit\n");
    child.waitExit();

    var v = [];
    var lines = child.stdout.str.split('\n');
    for (var i in lines) {
        if (lines[i]) {
            var info = lines[i].split('=>');
            var pth = info[1].trim();
            var libinfo = info[0].trim().split(' ');
            var lib = libinfo[0];
            var plat = libinfo[1].substring(1, libinfo[1].length - 1).split(',');

            if (lib.startsWith(libname + '.so.')) {
                v.push({ lib: lib, path: pth, info: plat });
            }
        }
    }
    return (v);
}

function monitorinfo()
{
    this._ObjectID = 'monitor-info';
    this._gm = require('_GenericMarshal');

    if (process.platform == 'win32')
    {
        this._user32 = this._gm.CreateNativeProxy('user32.dll');
        this._user32.CreateMethod('EnumDisplayMonitors');
        this._kernel32 = this._gm.CreateNativeProxy('kernel32.dll');
        this._kernel32.CreateMethod('GetLastError');

        this.getInfo = function getInfo()
        {
            var info = this;
            return (new promise(function (resolver, rejector) {
                this._monitorinfo = { resolver: resolver, rejector: rejector, self: info, callback: info._gm.GetGenericGlobalCallback(4) };
                this._monitorinfo.callback.info = this._monitorinfo;
                this._monitorinfo.dwData = info._gm.ObjectToPtr(this._monitorinfo);

                this._monitorinfo.callback.results = [];
                this._monitorinfo.callback.on('GlobalCallback', function OnMonitorInfo(hmon, hdc, r, user) {
                    if (this.ObjectToPtr_Verify(this.info, user)) {
                        var rb = r.Deref(0, 16).toBuffer();
                        this.results.push({ left: rb.readInt32LE(0), top: rb.readInt32LE(4), right: rb.readInt32LE(8), bottom: rb.readInt32LE(12) });

                        var r = this.info.self._gm.CreateInteger();
                        r.Val = 1;
                        return (r);
                    }
                });

                if (info._user32.EnumDisplayMonitors(0, 0, this._monitorinfo.callback, this._monitorinfo.dwData).Val == 0) {
                    rejector('LastError=' + info._kernel32.GetLastError().Val);
                    return;
                }
                else {
                    resolver(this._monitorinfo.callback.results);
                }

            }));
        }
    }
    else if(process.platform == 'linux')
    {
        // First thing we need to do, is determine where the X11 libraries are
        var askOS = false;
        try
        {
            if (require('user-sessions').isRoot()) { askOS = true; }
        }
        catch (e)
        { }

        if (askOS)
        {
            // Sufficient access rights to use ldconfig
            var x11info = getLibInfo('libX11');
            var xtstinfo = getLibInfo('libXtst');
            var xextinfo = getLibInfo('libXext');
            var ix;

            for(ix in x11info)
            {
                try
                {
                    this._gm.CreateNativeProxy(x11info[ix].path);
                    Object.defineProperty(this, 'Location_X11LIB', { value: x11info[ix].path });
                    break;
                }
                catch(ex)
                {
                }
            }
            for (ix in xtstinfo)
            {
                try
                {
                    this._gm.CreateNativeProxy(xtstinfo[ix].path);
                    Object.defineProperty(this, 'Location_X11TST', { value: xtstinfo[ix].path });
                    break;
                }
                catch (ex)
                {
                }
            }
            for (ix in xextinfo)
            {
                try
                {
                    this._gm.CreateNativeProxy(xextinfo[ix].path);
                    Object.defineProperty(this, 'Location_X11EXT', { value: xextinfo[ix].path });
                    break;
                }
                catch (ex)
                {
                }
            }
        }
        else
        {
            // Not enough access rights to use ldconfig, so manually search
            var fs = require('fs');
            var files = fs.readdirSync('/usr/lib');
            var files2;

            for (var i in files) {
                try {
                    if (files[i].split('libX11.so.').length > 1 && files[i].split('.').length == 3) {
                        Object.defineProperty(this, 'Location_X11LIB', { value: '/usr/lib/' + files[i] });
                    }
                    if (files[i].split('libXtst.so.').length > 1 && files[i].split('.').length == 3) {
                        Object.defineProperty(this, 'Location_X11TST', { value: '/usr/lib/' + files[i] });
                    }
                    if (files[i].split('libXext.so.').length > 1 && files[i].split('.').length == 3) {
                        Object.defineProperty(this, 'Location_X11EXT', { value: '/usr/lib/' + files[i] });
                    }

                    if (files[i].split('-linux-').length > 1) {
                        files2 = fs.readdirSync('/usr/lib/' + files[i]);
                        for (j in files2) {
                            if (files2[j].split('libX11.so.').length > 1 && files2[j].split('.').length == 3) {
                                Object.defineProperty(this, 'Location_X11LIB', { value: '/usr/lib/' + files[i] + '/' + files2[j] });
                            }
                            if (files2[j].split('libXtst.so.').length > 1 && files2[j].split('.').length == 3) {
                                Object.defineProperty(this, 'Location_X11TST', { value: '/usr/lib/' + files[i] + '/' + files2[j] });
                            }
                            if (files2[j].split('libXext.so.').length > 1 && files2[j].split('.').length == 3) {
                                Object.defineProperty(this, 'Location_X11EXT', { value: '/usr/lib/' + files[i] + '/' + files2[j] });
                            }
                        }
                    }
                } catch (ex) { }
            }
        }
        Object.defineProperty(this, 'kvm_x11_support', { value: (this.Location_X11LIB && this.Location_X11TST && this.Location_X11EXT)?true:false });

        if (this.Location_X11LIB)
        {
            this._X11 = this._gm.CreateNativeProxy(this.Location_X11LIB);
            this._X11.CreateMethod('XChangeProperty');
            this._X11.CreateMethod('XCloseDisplay');
            this._X11.CreateMethod('XCreateGC');
            this._X11.CreateMethod('XCreateWindow');
            this._X11.CreateMethod('XCreateSimpleWindow');
            this._X11.CreateMethod('XDefaultColormap');
            this._X11.CreateMethod('XDefaultScreen');
            this._X11.CreateMethod('XDrawLine');
            this._X11.CreateMethod('XDisplayHeight');
            this._X11.CreateMethod('XDisplayWidth');
            this._X11.CreateMethod('XFetchName');
            this._X11.CreateMethod('XFlush');
            this._X11.CreateMethod('XFree');
            this._X11.CreateMethod('XCreateGC');
            this._X11.CreateMethod('XGetWindowProperty');
            this._X11.CreateMethod('XInternAtom');
            this._X11.CreateMethod('XMapWindow');
            this._X11.CreateMethod({ method: 'XNextEvent', threadDispatch: true });
            this._X11.CreateMethod('XOpenDisplay');
            this._X11.CreateMethod('XRootWindow');
            this._X11.CreateMethod('XScreenCount');
            this._X11.CreateMethod('XScreenOfDisplay');
            this._X11.CreateMethod('XSelectInput');
            this._X11.CreateMethod('XSendEvent');
            this._X11.CreateMethod('XSetForeground');
            this._X11.CreateMethod('XSetFunction');
            this._X11.CreateMethod('XSetLineAttributes');
            this._X11.CreateMethod('XSetNormalHints');
            this._X11.CreateMethod('XSetSubwindowMode');

            this._X11.CreateMethod('XBlackPixel');
            this._X11.CreateMethod('XWhitePixel');
        }

        this.isUnity = function isUnity()
        {
            return (process.env['XDG_CURRENT_DESKTOP'] == 'Unity');
        }

        this.unDecorateWindow = function unDecorateWindow(display, window)
        {
            var MwmHints = this._gm.CreateVariable(40);
            var mwmHintsProperty = this._X11.XInternAtom(display, this._gm.CreateVariable('_MOTIF_WM_HINTS'), 0);
            MwmHints.Deref(0, 4).toBuffer().writeUInt32LE(1 << 1);
            this._X11.XChangeProperty(display, window, mwmHintsProperty, mwmHintsProperty, 32, 0, MwmHints, 5);
        }
        this.setWindowSizeHints = function setWindowSizeHints(display, window, x, y, width, height)
        {
            var sizeHints = this._gm.CreateVariable(80);
            sizeHints.Deref(0, 4).toBuffer().writeUInt32LE(PPosition | PSize);
            sizeHints.Deref(8, 4).toBuffer().writeUInt32LE(x);
            sizeHints.Deref(12, 4).toBuffer().writeUInt32LE(y);
            sizeHints.Deref(16, 4).toBuffer().writeUInt32LE(width);
            sizeHints.Deref(20, 4).toBuffer().writeUInt32LE(height);
            this._X11.XSetNormalHints(display, window, sizeHints);
        }
        this.setAlwaysOnTop = function setAlwaysOnTop(display, rootWindow, window)
        {
            var wmNetWmState = this._X11.XInternAtom(display, this._gm.CreateVariable('_NET_WM_STATE'), 1);
            var wmStateAbove = this._X11.XInternAtom(display, this._gm.CreateVariable('_NET_WM_STATE_ABOVE'), 1);

            var xclient = this._gm.CreateVariable(96);
            xclient.Deref(0, 4).toBuffer().writeUInt32LE(33);                   // ClientMessage type
            xclient.Deref(48, 4).toBuffer().writeUInt32LE(32);                  // Format 32
            wmNetWmState.pointerBuffer().copy(xclient.Deref(40, 8).toBuffer()); // message_type
            xclient.Deref(56, 8).toBuffer().writeUInt32LE(_NET_WM_STATE_ADD);   // data.l[0]
            wmStateAbove.pointerBuffer().copy(xclient.Deref(64, 8).toBuffer()); // data.l[1]

            window.pointerBuffer().copy(xclient.Deref(32, 8).toBuffer());       // window
            this._X11.XSendEvent(display, rootWindow, 0, SubstructureRedirectMask | SubstructureNotifyMask, xclient);
        }
        this.hideWindowIcon = function hideWindowIcon(display, rootWindow, window)
        {
            var wmNetWmState = this._X11.XInternAtom(display, this._gm.CreateVariable('_NET_WM_STATE'), 1);
            var wmStateSkip = this._X11.XInternAtom(display, this._gm.CreateVariable('_NET_WM_STATE_SKIP_TASKBAR'), 1);

            var xclient = this._gm.CreateVariable(96);
            xclient.Deref(0, 4).toBuffer().writeUInt32LE(33);                   // ClientMessage type
            xclient.Deref(48, 4).toBuffer().writeUInt32LE(32);                  // Format 32
            wmNetWmState.pointerBuffer().copy(xclient.Deref(40, 8).toBuffer()); // message_type
            xclient.Deref(56, 8).toBuffer().writeUInt32LE(_NET_WM_STATE_ADD);   // data.l[0]
            wmStateSkip.pointerBuffer().copy(xclient.Deref(64, 8).toBuffer());  // data.l[1]

            window.pointerBuffer().copy(xclient.Deref(32, 8).toBuffer());       // window
            this._X11.XSendEvent(display, rootWindow, 0, SubstructureRedirectMask | SubstructureNotifyMask, xclient);
        }

        this.getInfo = function getInfo()
        {
            var info = this;
            return (new promise(function (resolver, rejector)
            {
                var display = info._X11.XOpenDisplay(info._gm.CreateVariable(':0'));
                var screenCount = info._X11.XScreenCount(display).Val;
                var ret = [];
                for(var i=0;i<screenCount;++i)
                {
                    var screen = info._X11.XScreenOfDisplay(display, i);
                    ret.push({ left: 0, top: 0, right: info._X11.XDisplayWidth(display, i).Val, bottom: info._X11.XDisplayHeight(display, i).Val, screen: screen, screenId: i, display: display });
                }
                resolver(ret);
            }));
        }
    }
    else
    {
        throw (process.platform + ' not supported');
    }
}

module.exports = new monitorinfo();