#include "../../include/mgl/window/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) {
    return mgl_window_create_with_params(self, title, width, height, 0);
}

static int mgl_window_init(mgl_window *self, const char *title, int width, int height, mgl_window_handle parent_window, Window existing_window) {
    self->window = 0;

    mgl_context *context = mgl_get_context();

    if(parent_window == 0)
        parent_window = DefaultRootWindow(context->connection);

    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;

    if(existing_window) {
        if(!XChangeWindowAttributes(context->connection, existing_window, CWColormap | CWEventMask | CWBitGravity, &window_attr)) {
            fprintf(stderr, "XChangeWindowAttributes failed\n");
            XFreeColormap(context->connection, color_map);
            return -1;
        }
        XFreeColormap(context->connection, color_map);
        self->window = existing_window;
    } else {
        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;
        }

        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);
    context->gl.glEnableClientState(GL_VERTEX_ARRAY);
    context->gl.glEnableClientState(GL_COLOR_ARRAY);
    context->gl.glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    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);
    return 0;
}

int mgl_window_create_with_params(mgl_window *self, const char *title, int width, int height, mgl_window_handle parent_window) {
    return mgl_window_init(self, title, width, height, parent_window, None);
}

int mgl_window_init_from_existing_window(mgl_window *self, mgl_window_handle existing_window) {
    return mgl_window_init(self, "", 0, 0, 0, existing_window);
}

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_clear(mgl_window *self, mgl_color color) {
    mgl_context *context = mgl_get_context();
    context->gl.glClear(GL_COLOR_BUFFER_BIT);
    context->gl.glClearColor((float)color.r / 255.0f, (float)color.g / 255.0f, (float)color.b / 255.0f, (float)color.a / 255.0f);
}

bool mgl_window_poll_event(mgl_window *self, mgl_event *event) {
    /* TODO: Use |event| */

    Display *display = mgl_get_context()->connection;
    if(XPending(display)) {
        XEvent xev; /* TODO: Move to window struct */
        XNextEvent(display, &xev);
        mgl_window_on_receive_event(self, &xev);
        return true;
    } else {
        return false;
    }
}

void mgl_window_display(mgl_window *self) {
    mgl_context *context = mgl_get_context();
    context->gl.glXSwapBuffers(context->connection, self->window);
}