#include "../include/mgl/window.h"
#include "../include/mgl/mgl.h"
#include <X11/Xutil.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");
}

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

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

    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;

    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, &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);
    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 on_receive_x11_event(mgl_window *window, XEvent *xev) {
    
}

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);
    if(num_ready_fds > 0) {
        XEvent xev;
        while(XPending(display)) {
            XNextEvent(display, &xev);
            on_receive_x11_event(self, &xev);
        }
    } else if(num_ready_fds == -1) {
        /* TODO: */
        fprintf(stderr, "Disconnected!\n");
    }
}

void mgl_window_draw(mgl_window *self) {
    mgl_context *context = mgl_get_context();

    /* TODO: Get window size from window resize event instead */
    XWindowAttributes gwa;
    XGetWindowAttributes(context->connection, self->window, &gwa);

    context->gl.glViewport(0, 0, gwa.width, gwa.height);
    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);
}