#include "../../include/mgl/window/window.h"
#include "../../include/mgl/window/event.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) {
    self->size.x = width;
    self->size.y = height;

    mgl_view view;
    view.position = (mgl_vec2i){ 0, 0 };
    view.size = self->size;
    mgl_window_set_view(self, &view);
}

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);

    self->glx_context = context->gl.glXCreateContext(context->connection, context->visual_info, NULL, 1);
    if(!self->glx_context) {
        fprintf(stderr, "glXCreateContext failed\n");
        return -1;
    }

    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);
            mgl_window_deinit(self);
            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: Check for failure? */
    context->gl.glXMakeCurrent(context->connection, self->window, self->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_TEXTURE_COORD_ARRAY);
    context->gl.glEnableClientState(GL_COLOR_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->glx_context) {
        context->gl.glXDestroyContext(context->connection, self->glx_context);
        self->glx_context = NULL;
    }
    if(self->window) {
        XDestroyWindow(context->connection, self->window);
        self->window = 0;
    }
}

static mgl_key x11_keysym_to_mgl_key(KeySym key_sym) {
    if(key_sym >= XK_A && key_sym <= XK_Z)
        return MGL_KEY_A + (key_sym - XK_A);
    /* TODO: Check if this ever happens */
    if(key_sym >= XK_a && key_sym <= XK_z)
        return MGL_KEY_A + (key_sym - XK_a);
    if(key_sym >= XK_0 && key_sym <= XK_9)
        return MGL_KEY_NUM0 + (key_sym - XK_0);
    if(key_sym >= XK_KP_0 && key_sym <= XK_KP_9)
        return MGL_KEY_NUMPAD0 + (key_sym - XK_KP_0);

    /* TODO: Fill in the rest */
    switch(key_sym) {
        case XK_space:      return MGL_KEY_SPACE;
        case XK_BackSpace:  return MGL_KEY_BACKSPACE;
        case XK_Tab:        return MGL_KEY_TAB;
        case XK_Return:     return MGL_KEY_ENTER;
        case XK_Escape:     return MGL_KEY_ESCAPE;
        case XK_Delete:     return MGL_KEY_DELETE;
        case XK_Home:       return MGL_KEY_HOME;
        case XK_Left:       return MGL_KEY_LEFT;
        case XK_Up:         return MGL_KEY_UP;
        case XK_Right:      return MGL_KEY_RIGHT;
        case XK_Down:       return MGL_KEY_DOWN;
        case XK_Page_Up:    return MGL_KEY_PAGEUP;
        case XK_Page_Down:  return MGL_KEY_PAGEDOWN;
        case XK_End:        return MGL_KEY_END;
        case XK_F1:         return MGL_KEY_F1;
        case XK_F2:         return MGL_KEY_F2;
        case XK_F3:         return MGL_KEY_F3;
        case XK_F4:         return MGL_KEY_F4;
        case XK_F5:         return MGL_KEY_F5;
        case XK_F6:         return MGL_KEY_F6;
        case XK_F7:         return MGL_KEY_F7;
        case XK_F8:         return MGL_KEY_F8;
        case XK_F9:         return MGL_KEY_F9;
        case XK_F10:        return MGL_KEY_F10;
        case XK_F11:        return MGL_KEY_F11;
        case XK_F12:        return MGL_KEY_F12;
        case XK_F13:        return MGL_KEY_F13;
        case XK_F14:        return MGL_KEY_F14;
        case XK_F15:        return MGL_KEY_F15;
    }
    return MGL_KEY_UNKNOWN;
}

static mgl_mouse_button x11_button_to_mgl_button(unsigned int button) {
    switch(button) {
        case 1: return MGL_BUTTON_LEFT;
        case 2: return MGL_BUTTON_MIDDLE;
        case 3: return MGL_BUTTON_RIGHT;
        case 8: return MGL_BUTTON_XBUTTON1;
        case 9: return MGL_BUTTON_XBUTTON2;
    }
    return MGL_BUTTON_UNKNOWN;
}

/* Returns true if processed */
static bool mgl_window_on_receive_event(mgl_window *self, XEvent *xev, mgl_event *event, mgl_context *context) {
    /* TODO: Handle wm_delete_window event */
    switch(xev->type) {
        case KeyPress: {
            /* TODO: Fill with correct data */
            event->type = MGL_EVENT_KEY_PRESSED;
            event->key.code = x11_keysym_to_mgl_key(XKeycodeToKeysym(context->connection, xev->xkey.keycode, 0));
            event->key.alt = ((xev->xkey.state & Mod1Mask) != 0);
            event->key.control = ((xev->xkey.state & ControlMask) != 0);
            event->key.shift = ((xev->xkey.state & ShiftMask) != 0);
            event->key.system = ((xev->xkey.state & Mod5Mask) != 0); /* TODO: Fix, doesn't work */
            return true;
        }
        case KeyRelease: {
            /* TODO: Fill with correct data */
            event->type = MGL_EVENT_KEY_RELEASED;
            event->key.code = x11_keysym_to_mgl_key(XKeycodeToKeysym(context->connection, xev->xkey.keycode, 0));
            event->key.alt = ((xev->xkey.state & Mod1Mask) != 0);
            event->key.control = ((xev->xkey.state & ControlMask) != 0);
            event->key.shift = ((xev->xkey.state & ShiftMask) != 0);
            event->key.system = ((xev->xkey.state & Mod5Mask) != 0); /* TODO: Fix, doesn't work */
            return true;
        }
        case ButtonPress: {
            event->type = MGL_EVENT_MOUSE_BUTTON_PRESSED;
            event->mouse_button.button = x11_button_to_mgl_button(xev->xbutton.button);
            event->mouse_button.x = xev->xbutton.x;
            event->mouse_button.y = xev->xbutton.y;
            return true;
        }
        case ButtonRelease: {
            event->type = MGL_EVENT_MOUSE_BUTTON_RELEASED;
            event->mouse_button.button = x11_button_to_mgl_button(xev->xbutton.button);
            event->mouse_button.x = xev->xbutton.x;
            event->mouse_button.y = xev->xbutton.y;
            return true;
        }
        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);

                event->type = MGL_EVENT_RESIZED;
                event->size.width = self->size.x;
                event->size.height = self->size.y;
                return true;
            }
            return false;
        }
        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;

            event->type = MGL_EVENT_MOUSE_MOVED;
            event->mouse_move.x = self->cursor_position.x;
            event->mouse_move.y = self->cursor_position.y;
            return true;
        }
    }
    /*fprintf(stderr, "unhandled event type: %d\n", xev->type);*/
    event->type = MGL_EVENT_UNKNOWN;
    return false;
}

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

void mgl_window_set_view(mgl_window *self, mgl_view *new_view) {
    mgl_context *context = mgl_get_context();
    self->view = *new_view;
    context->gl.glViewport(new_view->position.x, self->size.y - new_view->size.y - new_view->position.y, new_view->size.x, new_view->size.y);
    context->gl.glMatrixMode(GL_PROJECTION);
    context->gl.glLoadIdentity();
    context->gl.glOrtho(0.0, new_view->size.x, new_view->size.y, 0.0, 0.0, 1.0);
}

void mgl_window_get_view(mgl_window *self, mgl_view *view) {
    *view = self->view;
}