#define WINDOWS_LEAN_AND_MEAN
#include <windows.h>
#include <string.h>

#define eq(s1,s2) (strcmp(s1,s2)==0)

#define WBUFF 2048
#define MAX_SHOW 100

module "winapi" {

class window {
  HWND hwnd;

  constructor (HWND h) {
    this->hwnd = h;
  }

  static lua_State *sL;

  static BOOL enum_callback(HWND hwnd,LPARAM data) {
    int ref = (int)data;
    lua_rawgeti(sL,LUA_REGISTRYINDEX,ref);
    push_new_window(sL,hwnd);
    lua_call(sL,1,0);
    return TRUE;
  }

  def handle() {
    lua_pushinteger(L,(int)this->hwnd);
    return 1;
  }

  static char buff[WBUFF];

  def get_text() {
    GetWindowText(this->hwnd,buff,sizeof(buff));
    lua_pushstring(L,buff);
    return 1;
  }

  def show(Int flags = SW_SHOW) {
    ShowWindow(this->hwnd,flags);
    return 0;
  }

  def get_position() {
    RECT rect;
    GetWindowRect(this->hwnd,&rect);
    lua_pushinteger(L,rect.left);
    lua_pushinteger(L,rect.top);
    return 2;
  }

  def get_bounds() {
    RECT rect;
    GetWindowRect(this->hwnd,&rect);
    lua_pushinteger(L,rect.right - rect.left);
    lua_pushinteger(L,rect.bottom - rect.top);
    return 2;
  }

  def is_visible() {
    lua_pushboolean(L,IsWindowVisible(this->hwnd));
    return 1;
  }

  def destroy () {
    DestroyWindow(this->hwnd);
    return 0;
  }

  def resize(Int x0, Int y0, Int w, Int h) {
    MoveWindow(this->hwnd,x0,y0,w,h,TRUE);
    return 0;
  }

  def send_message(Int msg, Int wparam, Int lparam) {
    SendMessage(this->hwnd,msg,wparam,lparam);
  }

  def enum_children(Value callback) {
    int ref;
    sL = L;
    lua_pushvalue(L,callback);
    ref  = luaL_ref(L,LUA_REGISTRYINDEX);
    EnumChildWindows(this->hwnd,&enum_callback,ref);
    luaL_unref(L,LUA_REGISTRYINDEX,ref);
    return 0;
  }

  def get_parent() {
    push_new_window(L,GetParent(this->hwnd));
    return 1;
  }

  def get_module_filename() {
    int sz = GetWindowModuleFileName(this->hwnd,buff,sizeof(buff));
    buff[sz] = '\0';
    lua_pushstring(L,buff);
    return 1;
  }

  def __tostring() {
    GetWindowText(this->hwnd,buff,sizeof(buff));
    if (strlen(buff) > MAX_SHOW) {
      strcpy(buff+MAX_SHOW,"...");
    }
    lua_pushstring(L,buff);
    return 1;
  }

  def __eq(window other) {
    lua_pushboolean(L,this->hwnd == other->hwnd);
    return 1;
  }

}

def find_window(Str cname, Str wname) {
  HWND hwnd;
  if (eq(cname,"")) {
    cname = NULL;
  }
  hwnd = FindWindow(cname,wname);
  push_new_window(L,hwnd);
  return 1;
}

def active_window() {
  push_new_window(L, GetActiveWindow());
  return 1;
}

def desktop_window() {
  push_new_window(L, GetDesktopWindow());
  return 1;
}

def enum_windows(Value callback) {
  int ref;
  sL = L;
  lua_pushvalue(L,callback);
  ref  = luaL_ref(L,LUA_REGISTRYINDEX);
  EnumWindows(&enum_callback,ref);
  luaL_unref(L,LUA_REGISTRYINDEX,ref);
  return 0;
}

def tile_windows(window parent, Boolean horiz, Value kids, Value bounds) {
  RECT rt;
  HWND *kids_arr;
  int i,n_kids;
  LPRECT lpRect = NULL;
  if (! lua_isnoneornil(L,bounds)) {
    lua_pushvalue(L,bounds);
    Int_get(rt.left,"left");
    Int_get(rt.top,"top");
    Int_get(rt.right,"right");
    Int_get(rt.bottom,"bottom");
    lua_pop(L,1);
  }
  n_kids = lua_objlen(L,kids);
  kids_arr = (HWND *)malloc(sizeof(HWND)*n_kids);
  for (i = 0; i < n_kids; ++i) {
    window *w;
    lua_rawgeti(L,kids,i+1);
    w = window_arg(L,-1);
    kids_arr[i] = w->hwnd;
  }
  TileWindows(parent->hwnd,horiz ? MDITILE_HORIZONTAL : MDITILE_VERTICAL, lpRect, n_kids, kids_arr);
  free(kids_arr);
  return 0;
}

def shell_exec(StrNil verb, Str file, StrNil parms, StrNil dir, Int show=SW_SHOWNORMAL) {
  int res = (int)ShellExecute(NULL,verb,file,parms,dir,show);
  if (res > 32) {
    lua_pushboolean(L,1);
    return 1;
  } else {
    const char *msg;
    switch(res) {
      #define check_err(NAME) case NAME: msg = #NAME; break;
      check_err(ERROR_FILE_NOT_FOUND);
      check_err(ERROR_PATH_NOT_FOUND);
      check_err(ERROR_BAD_FORMAT);
      check_err(SE_ERR_ACCESSDENIED);
      check_err(SE_ERR_ASSOCINCOMPLETE);
      check_err(SE_ERR_DLLNOTFOUND);
      check_err(SE_ERR_NOASSOC);
      check_err(SE_ERR_OOM);
      check_err(SE_ERR_SHARE);
      default: msg = "unknown error, probably DDE";
      #undef check_err
    }
    lua_pushnil(L);
    lua_pushstring(L,msg);
    return 2;
  }
}

constants {
  SW_HIDE,
  SW_MAXIMIZE,
  SW_MINIMIZE,
  SW_SHOWNORMAL
}

}