#include <stdlib.h>
#include <errno.h>
#include <windows.h>
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
#include "_whelk.h"

#define WHELK_KEYHANDLE		"HKEY"
#define whelk_checkkeyptr(L,n)	((HKEY *)luaL_checkudata(L,n,WHELK_KEYHANDLE))

static HKEY whelk_checkkey(lua_State *L,int n)
{
    HKEY *key=whelk_checkkeyptr(L,n);
    if (*key==INVALID_HANDLE_VALUE)
	luaL_error(L,"attempt to use a closed WIN32 registry key");
    return *key;
}

static HKEY *newkey(lua_State *L)
{
    HKEY *key=(HKEY *)lua_newuserdata(L,sizeof(HKEY));
    *key=INVALID_HANDLE_VALUE;
    luaL_getmetatable(L,WHELK_KEYHANDLE);
    lua_setmetatable(L,-2);
    return key;
}

static int get_value(lua_State *L)
{
    DWORD type,nb;
    HRESULT result;
    int retval=1;
    void *data;
    HKEY key=whelk_checkkey(L,1);
    const char *subkey=luaL_checkstring(L,2);
    const char *value=luaL_checkstring(L,3);
    result=whelk_reg_get_value(key,subkey,value,&type,&data,&nb);
    if (result!=ERROR_SUCCESS)
    {
	lua_pushnil(L);
	lua_pushfstring(L,"%s: Failed to get value",value);
	lua_pushinteger(L,result);
	retval=3;
    }
    else
	switch(type)
	{
	    case REG_SZ:
	    case REG_EXPAND_SZ:
		lua_pushstring(L,(char *)data);
		break;
	    case REG_DWORD:
		lua_pushnumber(L,*(DWORD *)data);
		break;
	    default:
		lua_pushnil(L);
		lua_pushfstring(L,"%s: Data is not a string or number",value);
		lua_pushinteger(L,ERROR_INVALID_PARAMETER);
		retval=3;
	}
    free(data);
    return retval;
}

static int set_value(lua_State *L)
{
    DWORD type;
    int nb;
    HRESULT result;
    lua_Number number;
    DWORD d;
    const void *data;
    HKEY key=whelk_checkkey(L,1);
    const char *subkey=luaL_checkstring(L,2);
    const char *value=luaL_checkstring(L,3);
    switch(lua_type(L,4))
    {
	case LUA_TSTRING:
	    data=lua_tostring(L,4);
	    type=REG_SZ;
	    nb=-1;
	    break;
	case LUA_TNUMBER:
	    number=lua_tonumber(L,4);
	    d=(DWORD)number;
	    if ((lua_Number)d!=number)
	    {
		lua_pushnil(L);
		lua_pushfstring(L,"%s: Data is not storable as DWORD",value);
		lua_pushinteger(L,ERROR_INVALID_PARAMETER);
	    }
	    data=&d;
	    type=REG_DWORD;
	    nb=sizeof(d);
	    break;
	case LUA_TNIL:
	    data=NULL;
	    type=REG_NONE;
	    nb=0;
	    break;
	default:
	    lua_pushnil(L);
	    lua_pushfstring(L,"%s: Data is not a string or number",value);
	    lua_pushinteger(L,ERROR_INVALID_PARAMETER);
	    return 3;
    }
    result=whelk_reg_set_value(key,subkey,value,type,data,nb);
    if (result!=ERROR_SUCCESS)
    {
	lua_pushnil(L);
	lua_pushfstring(L,"%s: Failed to set value",value);
	lua_pushinteger(L,result);
	return 3;
    }
    return 1;
}

static int delete_key(lua_State *L)
{
    HRESULT result;
    HKEY key=whelk_checkkey(L,1);
    const char *subkey=luaL_checkstring(L,2);
    result=whelk_reg_delete_key(key,subkey);
    if (result!=ERROR_SUCCESS)
    {
	lua_pushnil(L);
	lua_pushfstring(L,"%s: Failed to delete key",subkey);
	lua_pushinteger(L,result);
	return 3;
    }
    return 1;
}

static int reg_gc(lua_State *L)
{
    HKEY key=*whelk_checkkeyptr(L,1);
    if (key!=INVALID_HANDLE_VALUE)
	(void)whelk_reg_close_key(key);
    return 0;
}

static const luaL_Reg reg_methods[]={
    { "GetValue",get_value },
    { "SetValue",set_value },
    { "DeleteKey",delete_key },
    { "__gc",reg_gc },
    { NULL }
};

static void create_predefined_key(lua_State *L,HKEY key,const char *name)
{
    *newkey(L)=key;
    lua_setfield(L,-3,name);
}

void whelk_open_reg_keys(lua_State *L)
{
    luaL_newmetatable(L,WHELK_KEYHANDLE);
    lua_pushvalue(L,-1);
    lua_setfield(L,-2,"__index");
    luaL_register(L,NULL,reg_methods);
    create_predefined_key(L,HKEY_CLASSES_ROOT,"KEY_CLASSES_ROOT");
    create_predefined_key(L,HKEY_CURRENT_CONFIG,"KEY_CURRENT_CONFIG");
    create_predefined_key(L,HKEY_CURRENT_USER,"KEY_CURRENT_USER");
    create_predefined_key(L,HKEY_LOCAL_MACHINE,"KEY_LOCAL_MACHINE");
    create_predefined_key(L,HKEY_USERS,"KEY_USERS");
    lua_pop(L,1);
}