#include <X11/X.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdint.h>
#include <sys/socket.h>
#include <sys/un.h>

#include "../../Common/bin.h"
#include "../../Common/bits.h"
#include "../../Common/buf.h"
#include "../../Common/cfg.h"
#include "../../Common/lzw.h"
#include "../../Common/mat.h"
#include "../../Common/std.h"
#include "../../Common/str.h"
#include "../draw.h"
#include "display.h"

/* https://hereket.com/posts/from-scratch-x11-windowing/ */
/* https://gaultier.github.io/blog/write_a_video_game_from_scratch_like_1987.html
 */

static struct {
  uint32_t id;
  uint32_t colormap;
  uint32_t white;
  uint32_t black;
  uint32_t input_mask;
  uint16_t width;
  uint16_t height;
  uint16_t width_mm;
  uint16_t height_mm;
  uint16_t maps_min;
  uint16_t maps_max;
  uint32_t root_visual_id;
  uint8_t backing_store;
  uint8_t save_unders;
  uint8_t root_depth;
  uint8_t depths_count;
} plr_x11_root_screen;

static struct {
  uint32_t resource_id_base;
  uint32_t resource_id_mask;
} plr_x11_connection;

bool quited = false;

bool fileread(void *ctx, char *into, uint32_t bytes) {
  return com_std_read(ctx, into, bytes) == bytes;
}

bool fileskip(void *ctx, uint32_t bytes) { return com_std_sfwd(ctx, bytes); }

#define AUTH_ENTRY_MAGIC_COOKIE "MIT-MAGIC-COOKIE-1"

static struct plr_x11_auth_entry {
  uint16_t family;
  struct com_buf *auth_name;
  struct com_buf *auth_data;
  bool success;
} plr_x11_read_auth_entry(struct com_bin *b, struct com_buf *buf) {
  struct plr_x11_auth_entry result = {0};

  if (!com_bin_read_u16(b, &result.family))
    goto BREAK;
  uint16_t addres_len;
  if (!com_bin_read_u16(b, &addres_len))
    goto BREAK;
  if (!com_bin_skip(b, addres_len))
    goto BREAK;
  uint16_t display_len;
  if (!com_bin_read_u16(b, &display_len))
    goto BREAK;
  if (!com_bin_skip(b, display_len))
    goto BREAK;
  uint16_t name_len;
  if (!com_bin_read_u16(b, &name_len))
    goto BREAK;
  uint32_t name_idx;
  if (!com_bin_read_bufbi(b, buf, &name_idx, name_len))
    goto BREAK;
  uint16_t data_len;
  if (!com_bin_read_u16(b, &data_len))
    goto BREAK;
  uint32_t data_idx;
  if (!com_bin_read_bufbi(b, buf, &data_idx, data_len))
    goto BREAK;

  result.auth_name = com_buf_index_as(struct com_buf, buf, name_idx);
  result.auth_data = com_buf_index_as(struct com_buf, buf, data_idx);
  result.success = true;
  return result;
BREAK:
  com_std_printf("Failure to initialize X11\n");
  return result;
}

static bool plr_x11_handshake(com_std_fd xfd,
                              struct plr_x11_auth_entry auth_entry) {
  struct {
    uint8_t endianness;
    uint8_t pad0;
    uint16_t major_version;
    uint16_t minor_version;
    uint16_t auth_len;
    uint16_t auth_data_len;
    uint16_t pad1;
  } request = {
      .endianness = 'l',
      .major_version = 11,
      .auth_len = sizeof(AUTH_ENTRY_MAGIC_COOKIE) - 1, // IS -1 NEEDED?
      .auth_data_len = auth_entry.auth_data->len,
  };

  if (!com_std_write(xfd, &request, sizeof request))
    return false;
  if (!com_std_write(xfd, AUTH_ENTRY_MAGIC_COOKIE,
                     sizeof AUTH_ENTRY_MAGIC_COOKIE - 1))
    return false;
  /* Use 2 bytes back for padding. */
  if (!com_std_write(xfd, &auth_entry.auth_data->data[-2],
                     auth_entry.auth_data->len + 2))
    return false;

  struct {
    uint8_t success;
    uint8_t pad1;
    uint16_t major_version;
    uint16_t minor_version;
    uint16_t length;
  } response;

  if (!com_std_read(xfd, &response, sizeof response))
    return false;
  if (response.success != 1)
    return false;

  struct {
    uint32_t release_number;
    uint32_t resource_id_base;
    uint32_t resource_id_mask;
    uint32_t motion_buffer_size;
    uint16_t vendor_length;
    uint16_t maximum_request_length;
    uint8_t screens_in_root_count;
    uint8_t formats_count;
    uint8_t image_byte_order;
    uint8_t bitmap_format_bit_order;
    uint8_t bitmap_format_scanline_unit;
    uint8_t bitmap_format_scanline_pad;
    uint8_t min_keycode;
    uint8_t max_keycode;
    uint32_t pad2;
  } dyn_response;

  if (!com_std_read(xfd, &dyn_response, sizeof dyn_response))
    return false;

  /* Skip vendor and format info. */
  char scratch[1024];
  uint32_t skip = com_bits_nalign(dyn_response.vendor_length, 4);
  com_std_assert(skip <= sizeof scratch);
  com_std_assert(8 * dyn_response.formats_count <= sizeof scratch);
  if (!com_std_read(xfd, scratch, skip))
    return false;
  if (!com_std_read(xfd, scratch, 8 * dyn_response.formats_count))
    return false;
  if (!com_std_read(xfd, &plr_x11_root_screen, sizeof plr_x11_root_screen))
    return false;

  plr_x11_connection.resource_id_base = dyn_response.resource_id_base;
  plr_x11_connection.resource_id_mask = dyn_response.resource_id_mask;

  return true;
}

static inline uint32_t plr_x11_next_id(void) {
  static uint32_t cur_id = 0;
  cur_id = 1 + ((plr_x11_connection.resource_id_mask & (cur_id)) |
                plr_x11_connection.resource_id_base);
  return cur_id;
}

static uint32_t plr_x11_create_graphical_context(com_std_fd xfd) {
  uint32_t const gc_id = plr_x11_next_id();
  struct {
    uint8_t opcode;
    uint8_t pad1;
    uint16_t length;
    uint32_t id;
    uint32_t drawable;
    uint32_t bitmask;
    uint32_t value1;
  } request = {
      .opcode = 55,
      .length = 5,
      .id = gc_id,
      .drawable = plr_x11_root_screen.id,
      .bitmask = 8, /* TODO: Figure out. */
      .value1 = 0x0000ff00,
  };

  if (com_std_write(xfd, &request, sizeof request))
    return gc_id;
  else
    return 0;
}

static uint32_t plr_x11_create_window(com_std_fd xfd) {
/* TODO: Use the ones provided in headers ? */
#define FLAG_WIN_BG_PIXEL 2
#define FLAG_WIN_EVENT 0x800
#define EVENT_FLAG_EXPOSURE 0x8000
#define EVENT_FLAG_KEY_PRESS 0x1
#define EVENT_FLAG_KEY_RELEASE 0x2
#define EVENT_FLAG_BUTTON_PRESS 0x4
#define EVENT_FLAG_BUTTON_RELEASE 0x8

  uint32_t const window_id = plr_x11_next_id();
  struct {
    uint8_t opcode;
    uint8_t depth;
    uint16_t request_length;
    uint32_t window_id;
    uint32_t parent_id;
    uint16_t x;
    uint16_t y;
    uint16_t width;
    uint16_t height;
    uint16_t border_width;
    uint16_t class;
    uint32_t root_visual_id;
    uint32_t bitmask;
    uint32_t value1;
    uint32_t value2;
  } request = {
      .opcode = 1,
      .depth = 32,
      .request_length = 8 + 2,
      .window_id = window_id,
      .parent_id = plr_x11_root_screen.id,
      .width = COM_CFG_WIDTH,
      .height = COM_CFG_HEIGHT,
      .border_width = 0,
      .class = 1,
      .root_visual_id = plr_x11_root_screen.root_visual_id,
      .bitmask = FLAG_WIN_BG_PIXEL | FLAG_WIN_EVENT,
      .value1 = 0x00ffff00,
      .value2 = EVENT_FLAG_EXPOSURE | EVENT_FLAG_BUTTON_RELEASE |
                EVENT_FLAG_BUTTON_PRESS | EVENT_FLAG_KEY_PRESS |
                EVENT_FLAG_KEY_RELEASE,
  };

  if (com_std_write(xfd, &request, sizeof request))
    return window_id;
  else
    return 0;
}

static bool plr_x11_show_window(com_std_fd xfd, uint32_t window_id) {
  struct {
    uint8_t opcode;
    uint8_t pad1;
    uint16_t request_length;
    uint32_t window_id;
  } request = {
      .opcode = 8,
      .request_length = 2,
      .window_id = window_id,
  };
  return com_std_write(xfd, &request, sizeof request);
}

static uint32_t plr_x11_create_pixmap(com_std_fd xfd, uint32_t window_id) {
  uint32_t const pixmap_id = plr_x11_next_id();
  struct {
    uint8_t opcode;
    uint8_t depth;
    uint16_t length;
    uint32_t pixmap_id;
    uint32_t drawable;
    uint16_t width;
    uint16_t height;
  } request = {
      .opcode = 53,
      .depth = 32,
      .length = 4,
      .pixmap_id = pixmap_id,
      .drawable = window_id,
      .width = COM_CFG_WIDTH,
      .height = COM_CFG_HEIGHT,
  };

  if (com_std_write(xfd, &request, sizeof request))
    return pixmap_id;
  else
    return 0;
}

static bool
plr_x11_put_framebuffer(com_std_fd xfd, uint32_t gc_id, uint32_t window_id,
                        uint32_t pixmap_id,
                        uint32_t pixels[COM_CFG_WIDTH * COM_CFG_HEIGHT]) {
  uint32_t const padded =
      com_bits_nalign(4 * COM_CFG_WIDTH * COM_CFG_HEIGHT, 4);

  struct {
    uint8_t opcode;
    uint8_t format;
    uint16_t request_length;
    uint32_t drawable_id;
    uint32_t gc_id;
    uint16_t width;
    uint16_t height;
    uint16_t dst_x;
    uint16_t dst_y;
    uint8_t left_pad;
    uint8_t depth;
    uint16_t pad1;
  } request = {
      .opcode = 72,
      .format = 2, // ZPixmap
      .request_length = 6 + padded / 4,
      .drawable_id = pixmap_id,
      .gc_id = gc_id,
      .width = COM_CFG_WIDTH,
      .height = COM_CFG_HEIGHT,
      .dst_x = 0,
      .dst_y = 0,
      .depth = 32,
  };

  if (!com_std_write(xfd, &request, sizeof request))
    return false;
  if (!com_std_write(xfd, pixels, 4 * COM_CFG_WIDTH * COM_CFG_HEIGHT))
    return false;
  /* Use request memory for pad, it doesn't matter what we write. */
  uint32_t const padfinal = padded - (4 * COM_CFG_WIDTH * COM_CFG_HEIGHT);
  if (padfinal && !com_std_write(xfd, &request, padfinal))
    return false;

  return true;
}

static uint32_t pixel_buffer[COM_CFG_WIDTH * COM_CFG_HEIGHT];

// TODO: correct error handling.
extern int plr_display_x11_main(int argc, char *argv[]) {
  char test_string[] = "what is this?";
  char *compressed_string = NULL;
  uint32_t compressed_string_sz = 0;
  struct com_lzw_table table =
      com_lzw_infer_table(test_string, sizeof(test_string));
  bool test = com_lzw_compress(&table, test_string, sizeof(test_string),
                               &compressed_string, &compressed_string_sz);
  com_lzw_free_table(&table);
  com_std_assert(test);

  com_mat_t m0 = com_mat_identity();
  com_mat_t m1 = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};
  for (int i = 0; i < 16; ++i)
    m1.a[i] *= COM_FIX_FRACUNIT;

  com_mat_t t0 = com_mat_mul(m1, m0);
  com_mat_t t1 = com_mat_mul_reodered(com_mat_reoder(m1), m0);
  com_fix_print(t0.a[4]);
  com_fix_print(t1.a[4]);

  // com_vec_t v0 = com_mat_vec_project(com_mat_reoder(m0), com_vec_identity());
  // com_fix_print(v0.a[0]);

  // com_fix_run_tests();
  // com_fix_run_bench();
  // com_mat_run_bench();

  /* TODO: Move init to separate func. */
  /* Open X11 socket for communication. */
  com_std_fd const xfd = com_std_socket(false);
  if (!xfd) {
    com_std_printf("Failure to initialize X11\n");
    return -1;
  }

  if (!com_std_connect(xfd, false, "/tmp/.X11-unix/X0")) {
    com_std_printf("Failure to initialize X11\n");
    return -1;
  }

  /* First we need to authenticate X11 connection, which requires some funk. */
  /* We assume that $XAUTHORITY is set and I hope it is true. */
  char const *xauthpath = NULL;
  for (char **envp = &argv[argc + 1]; *envp != NULL; ++envp) {
    static const struct com_str xauthlit = com_str_lit("XAUTHORITY=");
    if (com_str_ext_prefixed(*envp, xauthlit)) {
      xauthpath = &((*envp)[xauthlit.len]);
      break;
    }
  }

  /* Open it and parse. */
  com_std_fd const xauthfd = com_std_open(xauthpath, COM_STD_OPEN_READ);
  if (xauthfd < 0) {
    com_std_printf("Failure to initialize X11\n");
    return -1;
  }

  com_buf_make_on_stack(char, xauthbuf, 1024, 0);
  struct com_bin xauthbin = {
      .ctx = (void *)(int64_t)xauthfd,
      .flags = COM_BIN_BIG_ENDIAN,
      .interface = {.readn = fileread, .skipn = fileskip}};

  /* Loop over auth entries until we find magic cookie one. */
  struct plr_x11_auth_entry auth_entry;
  do {
    com_buf_clear(xauthbuf);
    auth_entry = plr_x11_read_auth_entry(&xauthbin, xauthbuf);
  } while (auth_entry.success && auth_entry.family != 256);
  if (!auth_entry.success) {
    com_std_printf("Failure to initialize X11\n");
    return -1;
  }

  com_std_close(xauthfd);

  /* TODO: Check for auth_entry.name == MAGIC ? */
  if (!plr_x11_handshake(xfd, auth_entry)) {
    com_std_printf("Failure to initialize X11\n");
    return -1;
  }

  com_buf_free(xauthbuf);

  uint32_t const gc = plr_x11_create_graphical_context(xfd);
  if (!gc) {
    com_std_printf("Failure to initialize X11\n");
    return -1;
  }

  uint32_t const win = plr_x11_create_window(xfd);
  if (!win) {
    com_std_printf("Failure to initialize X11\n");
    return -1;
  }

  uint32_t const fb = plr_x11_create_pixmap(xfd, win);
  if (!fb) {
    com_std_printf("Failure to initialize X11\n");
    return -1;
  }

  // Display *display = XOpenDisplay(NULL);
  // if (NULL == display) {
  //   com_std_printf("Failed to initialize display");
  //   return -1;
  // }

  // Window root = DefaultRootWindow(display);
  // if (None == root) {
  //   com_std_printf("No root window found");
  //   XCloseDisplay(display);
  //   return -1;
  // }

  // int screen = DefaultScreen(display);
  // Visual *visual = DefaultVisual(display, screen);
  // int depth = DefaultDepth(display, screen);

  // Window window =
  //     XCreateSimpleWindow(display, root, 0, 0, WIDTH, HEIGHT, 0, 0,
  //     0xffffffff);
  // if (None == window) {
  //   com_std_printf("Failed to create window");
  //   XCloseDisplay(display);
  //   return -1;
  // }

  // XSizeHints *hints = XAllocSizeHints();
  // if (hints == NULL)
  //   return -1;

  // // Pinning min and max to the same values disables resizing
  // hints->flags = PMinSize | PMaxSize;
  // hints->min_width = hints->max_width = WIDTH;
  // hints->min_height = hints->max_height = HEIGHT;

  // XSetWMNormalHints(display, window, hints);
  // XFree(hints);

  // XSelectInput(display, window, ExposureMask | KeyPressMask);
  // XMapWindow(display, window);

  // GC gc = XCreateGC(display, window, 0, NULL);

  // Atom wm_delete_window = XInternAtom(display, "WM_DELETE_WINDOW",
  // False); XSetWMProtocols(display, window, &wm_delete_window, 1);

  // // TODO: can't be not true
  // int bytes_per_pixel = 4;
  // // char *pixel_buffer = (char *)malloc(WIDTH * HEIGHT *
  // bytes_per_pixel); char pixel_buffer[WIDTH * HEIGHT * bytes_per_pixel];

  // XImage *ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
  //                               pixel_buffer, WIDTH, HEIGHT, 32, 0);

  // if (!ximage) {
  //   com_std_printf("Failed to create XImage\n");
  //   // com_std_alloc(pixel_buffer, 0);
  //   XCloseDisplay(display);
  //   return -1;
  // }

  // int frame = 0;

  // XEvent event;
  // while (!quited) {
  //   XNextEvent(display, &event);

  //   switch (event.type) {
  //   case ClientMessage:
  //     if (event.xclient.data.l[0] == wm_delete_window) {
  //       XDestroyWindow(display, window);
  //       quited = true;
  //     }
  //     break;

  //   case Expose:
  //     frame += 2;

  //     plr_draw_screen((uint8_t *)pixel_buffer);

  //     // Draw the complete image onto the window when exposed
  //     XPutImage(display,
  //               window,       // Target drawable
  //               gc,           // Graphics Context
  //               ximage,       // Source XImage
  //               0, 0,         // Source coordinates (x, y)
  //               0, 0,         // Destination coordinates (x, y)
  //               WIDTH, HEIGHT // Dimensions to copy
  //     );
  //     break;
  //   }
  // }

  // XCloseDisplay(display);

  while (1) {
    plr_draw_screen((uint8_t *)pixel_buffer);

    if (!plr_x11_put_framebuffer(xfd, gc, win, fb, pixel_buffer)) {
      com_std_printf("Failure to drive X11\n");
      return -1;
    }

    if (!plr_x11_show_window(xfd, win)) {
      com_std_printf("Failure to drive X11\n");
      return -1;
    }
  }

  return 0;
}