#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <X11/Xft/Xft.h>
#include <X11/Xlib.h>
#include <X11/Xatom.h>

#include "pipe.h"
#include "bardata.h"

Display* display;
Window win;
GC gc;

XftFont* font = NULL;

static int bar_width = 1000;
static float width_ratio = 1;

static int err_code = 1;

void die(const char* fmt, ...) {
  va_list args;
  va_start(args, fmt);
  vfprintf(stderr, fmt, args);
  va_end(args);

  putc('\n', stderr);

  exit(err_code);
}
size_t utf8_strlen(const char *s) {
  size_t len = 0;
  while (*s) {
    if ((*s & 0xC0) != 0x80) len++;
    s++;
  }
  return len;
}

void load_font(const char* font_name) {
  XftFont* new_font = XftFontOpenName(display, DefaultScreen(display), font_name);
  if (new_font == NULL) {
    fprintf(stderr, "cannot open font %s\n", font_name);
    return;
  }

  if (font != NULL) {
    XftFontClose(display, font);
  }
  font = new_font;
}

void init_x(void) {
  display = XOpenDisplay(NULL);
  if (display == NULL) {
    die("could not open X display");
  }

  XSetWindowAttributes win_attr = {
    .override_redirect = 1,
    .background_pixel = 0x202020,
    .event_mask = ExposureMask | PropertyChangeMask,
  };

  Screen* screen = DefaultScreenOfDisplay(display);
  bar_width = WidthOfScreen(screen);

  win = XCreateWindow(
    display,
    DefaultRootWindow(display),
    0, 0,
    bar_width, bar_height,
    0,
    CopyFromParent,
    InputOutput,
    CopyFromParent,
    CWOverrideRedirect | CWBackPixel | CWEventMask,
    &win_attr
  );

  XClassHint class_hint;
  class_hint.res_name = "tsarbar";
  class_hint.res_class = "Bar";

  XSetClassHint(display, win, &class_hint);

  XMapWindow(display, win);

  load_font("monospace:size=10");

  gc = XCreateGC(display, win, 0, NULL);
  XSetForeground(display, gc, 0xFFFFFF);

  XLowerWindow(display, win);
  XFlush(display);
}

void deinit_x(void) {
  XftFontClose(display, font);
  XUnmapWindow(display, win);
  XDestroyWindow(display, win);
}

void draw_text(
  const char* text,
  int x,
  int y,
  const XftColor* fg_color,
  const XftColor* bg_color
) {
  XftDraw* xft_draw = XftDrawCreate(
    display,
    win,
    DefaultVisual(display, DefaultScreen(display)),
    DefaultColormap(display, DefaultScreen(display))
  );

  size_t width = font->max_advance_width * utf8_strlen(text);
  XftDrawRect(xft_draw, bg_color, x, y, width, bar_height);

  int dy = y + (bar_height - font->height) / 2 + font->ascent;
  XftDrawStringUtf8(xft_draw, fg_color, font, x, dy, (const FcChar8*)text, strlen(text));

  XftDrawDestroy(xft_draw);
}

void draw_comp_set(float pos_ratio, comp_t **set, int size) {
  int width = (size - 1) * comp_gap;
  for (int i = 0; i < size; i++) {
    comp_t *comp = set[i];
    width += font->max_advance_width * utf8_strlen(comp->data);
  }

  int x = (bar_width - width) * pos_ratio;
  x += padding * 2*(0.5 - pos_ratio); // Magic formula lol

  int y = 0;//(bar_height - font->height) / 2;
  for (int i = 0; i < size; i++) {
    comp_t *comp = set[i];

    draw_text(comp->data, x, y, comp->fg, comp->bg);
    x += font->max_advance_width * utf8_strlen(comp->data);
    x += comp_gap;
  }
}

int main(void) {
  init_pipe();
  init_x();
  init_bardata();

  while (true) {
    XEvent ev;
    while (XPending(display))
      XNextEvent(display, &ev);

    XClearWindow(display, win);
    XResizeWindow(display, win, bar_width, bar_height);

    draw_comp_set(0,   comps_left, left_size);
    draw_comp_set(0.5, comps_center, center_size);
    draw_comp_set(1,   comps_right, right_size);

    XFlush(display);
    await_change();
  }

  deinit_x();
  return 0;
}