#include "desk.h"

/******************************************************************************
 * load_string [Internal]
 *
 * This is basically a copy of user32/resource.c's LoadStringW. Necessary to
 * avoid importing user32, which is higher level than advapi32. Helper for
 * RegLoadMUIString.
 */
static int load_string(HINSTANCE hModule, UINT resId, LPWSTR pwszBuffer, INT cMaxChars)
{
    HGLOBAL hMemory;
    HRSRC hResource;
    WCHAR *pString;
    int idxString;

    /* Negative values have to be inverted. */
    if (HIWORD(resId) == 0xffff)
        resId = (UINT)(-((INT)resId));

    /* Load the resource into memory and get a pointer to it. */
    hResource = FindResourceW(hModule, MAKEINTRESOURCEW(LOWORD(resId >> 4) + 1), (LPWSTR)RT_STRING);
    if (!hResource) return 0;
    hMemory = LoadResource(hModule, hResource);
    if (!hMemory) return 0;
    pString = LockResource(hMemory);

    /* Strings are length-prefixed. Lowest nibble of resId is an index. */
    idxString = resId & 0xf;
    while (idxString--) pString += *pString + 1;

    /* If no buffer is given, return length of the string. */
    if (!pwszBuffer) return *pString;

    /* Else copy over the string, respecting the buffer size. */
    cMaxChars = (*pString < cMaxChars) ? *pString : (cMaxChars - 1);
    if (cMaxChars >= 0)
    {
        memcpy(pwszBuffer, pString+1, cMaxChars * sizeof(WCHAR));
        pwszBuffer[cMaxChars] = L'\0';
    }

    return cMaxChars;
}


/************************************************************************
 *  RegLoadMUIStringW
 *
 * @implemented
 */
LONG
RegLoadMUIStringW(IN HKEY hKey,
                  IN LPCWSTR pszValue  OPTIONAL,
                  OUT LPWSTR pszOutBuf,
                  IN DWORD cbOutBuf,
                  OUT LPDWORD pcbData OPTIONAL,
                  IN DWORD Flags,
                  IN LPCWSTR pszDirectory  OPTIONAL)
{
    DWORD dwValueType, cbData;
    LPWSTR pwszTempBuffer = NULL, pwszExpandedBuffer = NULL;
    LONG result;

    /* Parameter sanity checks. */
    if (!hKey || !pszOutBuf)
        return ERROR_INVALID_PARAMETER;

    if (pszDirectory && *pszDirectory)
    {
        //FIXME("BaseDir parameter not yet supported!\n");
        return ERROR_INVALID_PARAMETER;
    }

    /* Check for value existence and correctness of it's type, allocate a buffer and load it. */
    result = RegQueryValueExW(hKey, pszValue, NULL, &dwValueType, NULL, &cbData);
    if (result != ERROR_SUCCESS) goto cleanup;
    if (!(dwValueType == REG_SZ || dwValueType == REG_EXPAND_SZ) || !cbData)
    {
        result = ERROR_FILE_NOT_FOUND;
        goto cleanup;
    }
    pwszTempBuffer = HeapAlloc(GetProcessHeap(), 0, cbData);
    if (!pwszTempBuffer)
    {
        result = ERROR_NOT_ENOUGH_MEMORY;
        goto cleanup;
    }
    result = RegQueryValueExW(hKey, pszValue, NULL, &dwValueType, (LPBYTE)pwszTempBuffer, &cbData);
    if (result != ERROR_SUCCESS) goto cleanup;

    /* Expand environment variables, if appropriate, or copy the original string over. */
    if (dwValueType == REG_EXPAND_SZ)
    {
        cbData = ExpandEnvironmentStringsW(pwszTempBuffer, NULL, 0) * sizeof(WCHAR);
        if (!cbData) goto cleanup;
        pwszExpandedBuffer = HeapAlloc(GetProcessHeap(), 0, cbData);
        if (!pwszExpandedBuffer)
        {
            result = ERROR_NOT_ENOUGH_MEMORY;
            goto cleanup;
        }
        ExpandEnvironmentStringsW(pwszTempBuffer, pwszExpandedBuffer, cbData);
    }
    else
    {
        pwszExpandedBuffer = HeapAlloc(GetProcessHeap(), 0, cbData);
        memcpy(pwszExpandedBuffer, pwszTempBuffer, cbData);
    }

    /* If the value references a resource based string, parse the value and load the string.
     * Else just copy over the original value. */
    result = ERROR_SUCCESS;
    if (*pwszExpandedBuffer != L'@') /* '@' is the prefix for resource based string entries. */
    {
        lstrcpynW(pszOutBuf, pwszExpandedBuffer, cbOutBuf / sizeof(WCHAR));
    }
    else
    {
        WCHAR *pComma = wcsrchr(pwszExpandedBuffer, L',');
        UINT uiStringId;
        HMODULE hModule;

        /* Format of the expanded value is 'path_to_dll,-resId' */
        if (!pComma || pComma[1] != L'-')
        {
            result = ERROR_BADKEY;
            goto cleanup;
        }

        uiStringId = _wtoi(pComma+2);
        *pComma = L'\0';

        hModule = LoadLibraryExW(pwszExpandedBuffer + 1, NULL, LOAD_LIBRARY_AS_DATAFILE);
        if (!hModule || !load_string(hModule, uiStringId, pszOutBuf, cbOutBuf / sizeof(WCHAR)))
            result = ERROR_BADKEY;
        FreeLibrary(hModule);
    }

cleanup:
    HeapFree(GetProcessHeap(), 0, pwszTempBuffer);
    HeapFree(GetProcessHeap(), 0, pwszExpandedBuffer);
    return result;
}