/*
 * mii_emu.c
 *
 * Copyright (C) 2023 Michel Pollet <buserror@gmail.com>
 *
 * SPDX-License-Identifier: MIT
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdarg.h>
#include <string.h>
#include <math.h>
#include <assert.h>
#include <time.h>
#include <limits.h>

#define NK_INCLUDE_FIXED_TYPES
#define NK_INCLUDE_STANDARD_IO
#define NK_INCLUDE_STANDARD_VARARGS
#define NK_INCLUDE_DEFAULT_ALLOCATOR
#define NK_INCLUDE_VERTEX_BUFFER_OUTPUT
#define NK_INCLUDE_FONT_BAKING
#define NK_INCLUDE_DEFAULT_FONT
#define NK_BUTTON_TRIGGER_ON_RELEASE
#include "nuklear.h"

#define NK_XLIB_GL3_IMPLEMENTATION
#define NK_XLIB_LOAD_OPENGL_EXTENSIONS
#include "nuklear_xlib_gl3.h"

#include "mii.h"
#include "mish.h"

#define WINDOW_WIDTH 1280
#define WINDOW_HEIGHT 720 // (10 + (192) * 3)

#define MAX_VERTEX_BUFFER 512 * 1024
#define MAX_ELEMENT_BUFFER 128 * 1024

void
mii_nuklear(
		mii_t *mii,
		struct nk_context *ctx);
void
mii_nuklear_init(
		mii_t *mii,
		struct nk_context *ctx);
/* ===============================================================
 *
 *                          DEMO
 *
 * ===============================================================*/
struct XWindow {
    Display *dpy;
    Window win;
    XVisualInfo *vis;
    Colormap cmap;
    XSetWindowAttributes swa;
    XWindowAttributes attr;
    GLXFBConfig fbc;
    Atom wm_delete_window;
    int width, height;
};
static int gl_err = nk_false;
static int gl_error_handler(Display *dpy, XErrorEvent *ev)
{NK_UNUSED(dpy); NK_UNUSED(ev); gl_err = nk_true;return 0;}

static void
die(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    vfprintf(stderr, fmt, ap);
    va_end(ap);
    fputs("\n", stderr);
    exit(EXIT_FAILURE);
}

static int
has_extension(const char *string, const char *ext)
{
    const char *start, *where, *term;
    where = strchr(ext, ' ');
    if (where || *ext == '\0')
        return nk_false;

    for (start = string;;) {
        where = strstr((const char*)start, ext);
        if (!where) break;
        term = where + strlen(ext);
        if (where == start || *(where - 1) == ' ') {
            if (*term == ' ' || *term == '\0')
                return nk_true;
        }
        start = term;
    }
    return nk_false;
}

struct nk_font *nk_main_font = NULL;

/* global now, mish commands use it */
mii_t g_mii = {};

int
main(
        int argc,
        const char *argv[])
{
    /* Platform */
    int running = 1;
    struct XWindow win;
    GLXContext glContext;
    struct nk_context *ctx;
    struct nk_colorf bg;

	mii_init(&g_mii);
    int idx = 1;
    uint32_t flags = MII_INIT_DEFAULT;
    int r = mii_argv_parse(&g_mii, argc, argv, &idx, &flags);
    if (r == 0) {
        printf("mii: Invalid argument %s, skipped\n", argv[idx]);
    } else if (r == -1)
        exit(1);
    mii_prepare(&g_mii, flags);
    mish_prepare(1);
    mish_set_command_parameter(MISH_FCC('m','i','i',' '), &g_mii);
    printf("MISH_TELNET_PORT = %s\n", getenv("MISH_TELNET_PORT"));

    memset(&win, 0, sizeof(win));
    win.dpy = XOpenDisplay(NULL);
    if (!win.dpy) die("Failed to open X display\n");
    {
        /* check glx version */
        int glx_major, glx_minor;
        if (!glXQueryVersion(win.dpy, &glx_major, &glx_minor))
            die("[X11]: Error: Failed to query OpenGL version\n");
        if ((glx_major == 1 && glx_minor < 3) || (glx_major < 1))
            die("[X11]: Error: Invalid GLX version!\n");
    }
    {
        /* find and pick matching framebuffer visual */
        int fb_count;
        static GLint attr[] = {
            GLX_X_RENDERABLE,   True,
            GLX_DRAWABLE_TYPE,  GLX_WINDOW_BIT,
            GLX_RENDER_TYPE,    GLX_RGBA_BIT,
            GLX_X_VISUAL_TYPE,  GLX_TRUE_COLOR,
            GLX_RED_SIZE,       8,
            GLX_GREEN_SIZE,     8,
            GLX_BLUE_SIZE,      8,
            GLX_ALPHA_SIZE,     8,
            GLX_DEPTH_SIZE,     24,
            GLX_STENCIL_SIZE,   8,
            GLX_DOUBLEBUFFER,   True,
            None
        };
        GLXFBConfig *fbc;
        fbc = glXChooseFBConfig(win.dpy, DefaultScreen(win.dpy), attr, &fb_count);
        if (!fbc) die("[X11]: Error: failed to retrieve framebuffer configuration\n");
        {
            /* pick framebuffer with most samples per pixel */
            int i;
            int fb_best = -1, best_num_samples = -1;
            for (i = 0; i < fb_count; ++i) {
                XVisualInfo *vi = glXGetVisualFromFBConfig(win.dpy, fbc[i]);
                if (vi) {
                    int sample_buffer, samples;
                    glXGetFBConfigAttrib(win.dpy, fbc[i], GLX_SAMPLE_BUFFERS, &sample_buffer);
                    glXGetFBConfigAttrib(win.dpy, fbc[i], GLX_SAMPLES, &samples);
                    if ((fb_best < 0) || (sample_buffer && samples > best_num_samples))
                        fb_best = i, best_num_samples = samples;
                    XFree(vi);
                }
            }
            win.fbc = fbc[fb_best];
            XFree(fbc);
            win.vis = glXGetVisualFromFBConfig(win.dpy, win.fbc);
        }
    }
    {
        /* create window */
        win.cmap = XCreateColormap(win.dpy, RootWindow(win.dpy, win.vis->screen), win.vis->visual, AllocNone);
        win.swa.colormap =  win.cmap;
        win.swa.background_pixmap = None;
        win.swa.border_pixel = 0;
        win.swa.event_mask =
            ExposureMask | KeyPressMask | KeyReleaseMask |
            ButtonPress | ButtonReleaseMask| ButtonMotionMask |
            Button1MotionMask | Button3MotionMask | Button4MotionMask | Button5MotionMask|
            PointerMotionMask| StructureNotifyMask;
        win.win = XCreateWindow(win.dpy, RootWindow(win.dpy, win.vis->screen), 0, 0,
            WINDOW_WIDTH, WINDOW_HEIGHT, 0, win.vis->depth, InputOutput,
            win.vis->visual, CWBorderPixel|CWColormap|CWEventMask, &win.swa);
        if (!win.win) die("[X11]: Failed to create window\n");
        XFree(win.vis);

        char title[128];
        sprintf(title, "MII //e Emulator");
        char *telnet = getenv("MISH_TELNET_PORT");
        if (telnet)
            sprintf(title + strlen(title), " (telnet port %s)", telnet);
        else
            sprintf(title + strlen(title), " (telnet disabled)");
        XStoreName(win.dpy, win.win, title);
        XMapWindow(win.dpy, win.win);
        win.wm_delete_window = XInternAtom(win.dpy, "WM_DELETE_WINDOW", False);
        XSetWMProtocols(win.dpy, win.win, &win.wm_delete_window, 1);
    }
    {
        /* create opengl context */
        typedef GLXContext(*glxCreateContext)(Display*, GLXFBConfig, GLXContext, Bool, const int*);
        int(*old_handler)(Display*, XErrorEvent*) = XSetErrorHandler(gl_error_handler);
        const char *extensions_str = glXQueryExtensionsString(win.dpy, DefaultScreen(win.dpy));
        glxCreateContext create_context = (glxCreateContext)
            glXGetProcAddressARB((const GLubyte*)"glXCreateContextAttribsARB");

        gl_err = nk_false;
        if (!has_extension(extensions_str, "GLX_ARB_create_context") || !create_context) {
            fprintf(stdout, "[X11]: glXCreateContextAttribARB() not found...\n");
            fprintf(stdout, "[X11]: ... using old-style GLX context\n");
            glContext = glXCreateNewContext(win.dpy, win.fbc, GLX_RGBA_TYPE, 0, True);
        } else {
            GLint attr[] = {
                GLX_CONTEXT_MAJOR_VERSION_ARB, 3,
                GLX_CONTEXT_MINOR_VERSION_ARB, 0,
                None
            };
            glContext = create_context(win.dpy, win.fbc, 0, True, attr);
            XSync(win.dpy, False);
            if (gl_err || !glContext) {
                /* Could not create GL 3.0 context. Fallback to old 2.x context.
                 * If a version below 3.0 is requested, implementations will
                 * return the newest context version compatible with OpenGL
                 * version less than version 3.0.*/
                attr[1] = 1; attr[3] = 0;
                gl_err = nk_false;
                fprintf(stdout, "[X11] Failed to create OpenGL 3.0 context\n");
                fprintf(stdout, "[X11] ... using old-style GLX context!\n");
                glContext = create_context(win.dpy, win.fbc, 0, True, attr);
            }
        }
        XSync(win.dpy, False);
        XSetErrorHandler(old_handler);
        if (gl_err || !glContext)
            die("[X11]: Failed to create an OpenGL context\n");
        glXMakeCurrent(win.dpy, win.win, glContext);
    }
//extern const unsigned char mii_proggy_data[];
//extern const unsigned int mii_proggy_size;
extern const unsigned char mii_droid_data[];
extern const unsigned int mii_droid_size;

    ctx = nk_x11_init(win.dpy, win.win);
    /* Load Fonts: if none of these are loaded a default font will be used  */
    {
        struct nk_font_atlas *atlas;
        nk_x11_font_stash_begin(&atlas);
		struct nk_font_config cfg = nk_font_config(0);
#if 0
		nk_rune ranges[] = {
			0x0020, 0x007E,    	/* Ascii */
			0x00A1, 0x00FF,    	/* Symbols + Umlaute */
			0
		};
#endif
		cfg.range = nk_font_default_glyph_ranges();
		cfg.oversample_h = cfg.oversample_v = 1;
		cfg.pixel_snap = true;
        nk_main_font = nk_font_atlas_add_from_memory(atlas,
                (void*)mii_droid_data, mii_droid_size, 20, &cfg);
        nk_x11_font_stash_end();
        /*nk_style_load_all_cursors(ctx, atlas->cursors);*/
        if (nk_main_font)
            nk_style_set_font(ctx, &nk_main_font->handle);
    }

    mii_nuklear_init(&g_mii, ctx);

    bg.r = 0.0f; bg.g = 0.0f; bg.b = 0.0f; bg.a = 1.0f;
//    bg.r = 0.8f; bg.g = 0.8f; bg.b = 0.8f; bg.a = 1.0f;
    while (running) {
        /* Input */
        XEvent evt;
        nk_input_begin(ctx);
        while (XPending(win.dpy)) {
            XNextEvent(win.dpy, &evt);
            if (evt.type == ClientMessage) goto cleanup;
            if (XFilterEvent(&evt, win.win)) continue;
            nk_x11_handle_event(&evt);
        }
        nk_input_end(ctx);

        /* GUI */
        mii_nuklear(&g_mii, ctx);

        /* Draw */
        XGetWindowAttributes(win.dpy, win.win, &win.attr);
        glViewport(0, 0, win.width, win.height);
        glClear(GL_COLOR_BUFFER_BIT);
        glClearColor(bg.r, bg.g, bg.b, bg.a);
        /* IMPORTANT: `nk_x11_render` modifies some global OpenGL state
         * with blending, scissor, face culling, depth test and viewport and
         * defaults everything back into a default state.
         * Make sure to either a.) save and restore or b.) reset your own state after
         * rendering the UI. */
        nk_x11_render(NK_ANTI_ALIASING_ON, MAX_VERTEX_BUFFER, MAX_ELEMENT_BUFFER);
        glXSwapBuffers(win.dpy, win.win);
    }
    mii_dispose(&g_mii);
cleanup:
    nk_x11_shutdown();
    glXMakeCurrent(win.dpy, 0, 0);
    glXDestroyContext(win.dpy, glContext);
    XUnmapWindow(win.dpy, win.win);
    XFreeColormap(win.dpy, win.cmap);
    XDestroyWindow(win.dpy, win.win);
    XCloseDisplay(win.dpy);
    return 0;

}