#include "../include/mgl/window.h"
#include "../include/mgl/mgl.h"
#include <X11/Xutil.h>
#include <errno.h>
#include <stdio.h>

/* TODO: check for glx swap control extension string (GLX_EXT_swap_control, etc) */
static void set_vertical_sync_enabled(Window window, int enabled) {
    int result = 0;
    mgl_context *context = mgl_get_context();

    if(context->gl.glXSwapIntervalEXT) {
        context->gl.glXSwapIntervalEXT(context->connection, window, enabled ? 1 : 0);
    } else if(context->gl.glXSwapIntervalMESA) {
        result = context->gl.glXSwapIntervalMESA(enabled ? 1 : 0);
    } else if(context->gl.glXSwapIntervalSGI) {
        result = context->gl.glXSwapIntervalSGI(enabled ? 1 : 0);
    } else {
        static int warned = 0;
        if (!warned) {
            warned = 1;
            fprintf(stderr, "Warning: setting vertical sync not supported\n");
        }
    }

    if(result != 0)
        fprintf(stderr, "Warning: setting vertical sync failed\n");
}

static void mgl_window_on_resize(mgl_window *self, int width, int height) {
    mgl_context *context = mgl_get_context();
    self->size.x = width;
    self->size.y = height;
    context->gl.glViewport(0, 0, self->size.x, self->size.y);
    context->gl.glMatrixMode(GL_PROJECTION);
    context->gl.glLoadIdentity();
    context->gl.glOrtho(0.0, width, height, 0.0, -1.0, 1.0);
}

int mgl_window_create(mgl_window *self, const char *title, int width, int height, mgl_window_callback *callback) {
    return mgl_window_create_with_params(self, title, width, height, DefaultRootWindow(mgl_get_context()->connection), callback);
}

int mgl_window_create_with_params(mgl_window *self, const char *title, int width, int height, unsigned long parent_window, mgl_window_callback *callback) {
    self->window = 0;
    self->callback = *callback;

    mgl_context *context = mgl_get_context();

    Colormap color_map = XCreateColormap(context->connection, DefaultRootWindow(context->connection), ((XVisualInfo*)context->visual_info)->visual, AllocNone);
    if(!color_map) {
        fprintf(stderr, "XCreateColormap failed\n");
        return -1;
    }

    XSetWindowAttributes window_attr;
    window_attr.colormap = color_map;
    window_attr.event_mask = 
        KeyPressMask | KeyReleaseMask |
        ButtonPressMask | ButtonReleaseMask |
        PointerMotionMask | Button1MotionMask | Button2MotionMask | Button3MotionMask | Button4MotionMask | Button5MotionMask | ButtonMotionMask |
        StructureNotifyMask;
    window_attr.bit_gravity = NorthWestGravity;

    self->window = XCreateWindow(context->connection, parent_window, 0, 0, width, height, 0,
        ((XVisualInfo*)context->visual_info)->depth, InputOutput, ((XVisualInfo*)context->visual_info)->visual,
        CWColormap | CWEventMask | CWBitGravity, &window_attr);
    XFreeColormap(context->connection, color_map);
    if(!self->window) {
        fprintf(stderr, "XCreateWindow failed\n");
        mgl_window_deinit(self);
        return -1;
    }

    /* TODO: Test utf8 */
    XStoreName(context->connection, self->window, title);
    XMapWindow(context->connection, self->window);
    XFlush(context->connection);

    /* TODO: Switch current when rendering to another window, and set current to NULL when destroying the currently selected context */
    context->gl.glXMakeCurrent(context->connection, self->window, context->glx_context);
    set_vertical_sync_enabled(self->window, 1);
    context->gl.glEnable(GL_TEXTURE_2D);
    context->gl.glEnable(GL_BLEND);
    context->gl.glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    XWindowAttributes gwa;
    gwa.width = 0;
    gwa.height = 0;
    XGetWindowAttributes(context->connection, self->window, &gwa);

    Window dummy_w;
    int dummy_i;
    unsigned int dummy_u;
    XQueryPointer(context->connection, self->window, &dummy_w, &dummy_w, &dummy_i, &dummy_i, &self->cursor_position.x, &self->cursor_position.y, &dummy_u);

    mgl_window_on_resize(self, gwa.width, gwa.height);
    mgl_window_draw(self);
    return 0;
}

void mgl_window_deinit(mgl_window *self) {
    mgl_context *context = mgl_get_context();
    if(self->window) {
        XDestroyWindow(context->connection, self->window);
        self->window = 0;
    }
}

static void mgl_window_on_receive_event(mgl_window *self, XEvent *xev) {
    switch(xev->type) {
        case ConfigureNotify: {
            while(XCheckTypedWindowEvent(mgl_get_context()->connection, self->window, ConfigureNotify, xev)) {}
            if(xev->xconfigure.width != self->size.x || xev->xconfigure.height != self->size.x) {
                mgl_window_on_resize(self, xev->xconfigure.width, xev->xconfigure.height);
                /*fprintf(stderr, "resize!\n");*/
            }
            break;
        }
        case MotionNotify: {
            while(XCheckTypedWindowEvent(mgl_get_context()->connection, self->window, MotionNotify, xev)) {}
            self->cursor_position.x = xev->xmotion.x;
            self->cursor_position.y = xev->xmotion.y;
            break;
        }
    }
}

void mgl_window_events_poll(mgl_window *self) {
    Display *display = mgl_get_context()->connection;
    const int x11_fd = ConnectionNumber(display);

    fd_set in_fds;
    FD_ZERO(&in_fds); /* TODO: Optimize */
    FD_SET(x11_fd, &in_fds);

    struct timeval tv;
    tv.tv_sec = 0;
    tv.tv_usec = 0;
    /*tv.tv_sec = timeout_ms / 1000;
    tv.tv_usec = (timeout_ms * 1000) - (tv.tv_sec * 1000 * 1000);*/

    /* TODO: Is this needed when using XPending? */
    /*const int num_ready_fds = select(1 + x11_fd, &in_fds, NULL, NULL, &tv);*/
    const int num_ready_fds = 1;
    if(num_ready_fds > 0) {
        XEvent xev;
        while(self->window && XPending(display)) {
            XNextEvent(display, &xev);
            mgl_window_on_receive_event(self, &xev);
        }
    } else if(num_ready_fds == -1 && errno != EINTR) {
        /* TODO: */
        fprintf(stderr, "Disconnected!\n");
    }
}

void mgl_window_draw(mgl_window *self) {
    mgl_context *context = mgl_get_context();
    context->gl.glClear(GL_COLOR_BUFFER_BIT);
    context->gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    if(self->callback.draw)
        self->callback.draw(self, self->callback.userdata);
    context->gl.glXSwapBuffers(context->connection, self->window);
}