/* Copyright 2014 the SumatraPDF project authors (see AUTHORS file).
   License: GPLv3 */

#include "BaseUtil.h"
#include "uia/PageProvider.h"

#include "DisplayModel.h"
#include "uia/Constants.h"
#include "uia/DocumentProvider.h"
#include "uia/Provider.h"
#include "TextSelection.h"

SumatraUIAutomationPageProvider::SumatraUIAutomationPageProvider(int pageNum,HWND canvasHwnd, DisplayModel*dm, SumatraUIAutomationDocumentProvider* root) :
    refCount(1), pageNum(pageNum),
    canvasHwnd(canvasHwnd), dm(dm),
    root(root), sibling_prev(NULL), sibling_next(NULL),
    released(false)
{
    //root->AddRef(); Don't add refs to our parent & owner. 
}

SumatraUIAutomationPageProvider::~SumatraUIAutomationPageProvider()
{
}

int SumatraUIAutomationPageProvider::GetPageNum() const
{
    return pageNum;
}

SumatraUIAutomationPageProvider* SumatraUIAutomationPageProvider::GetNextPage()
{
    return sibling_next;
}

SumatraUIAutomationPageProvider* SumatraUIAutomationPageProvider::GetPreviousPage()
{
    return sibling_prev;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::QueryInterface(REFIID riid, void **ppv)
{
    static const QITAB qit[] = {
        QITABENT(SumatraUIAutomationPageProvider, IRawElementProviderSimple),
        QITABENT(SumatraUIAutomationPageProvider, IRawElementProviderFragment),
        QITABENT(SumatraUIAutomationPageProvider, IValueProvider),
        { 0 }
    };
    return QISearch(this, qit, riid, ppv);
}

ULONG STDMETHODCALLTYPE SumatraUIAutomationPageProvider::AddRef(void)
{
    return InterlockedIncrement(&refCount);
}

ULONG STDMETHODCALLTYPE SumatraUIAutomationPageProvider::Release(void)
{
    LONG res = InterlockedDecrement(&refCount);
    CrashIf(res < 0);
    if (0 == res)
        delete this;
    return res;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::Navigate(enum NavigateDirection direction, IRawElementProviderFragment **pRetVal)
{
    if (pRetVal == NULL)
        return E_POINTER;
    
    // disallow traverse if we are lingering
    if (released)
        return E_FAIL;
    
    *pRetVal =  NULL;
    if (direction == NavigateDirection_PreviousSibling) {
        *pRetVal = sibling_prev;
    } else if (direction == NavigateDirection_NextSibling) {
        *pRetVal = sibling_next;
    } else if (direction == NavigateDirection_FirstChild ||
             direction == NavigateDirection_LastChild) {
        // do nothing
    } else if (direction == NavigateDirection_Parent) {
        *pRetVal = root;
    } else {
        return E_INVALIDARG;
    }

    if (*pRetVal)
        (*pRetVal)->AddRef();
    return S_OK;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::GetRuntimeId(SAFEARRAY **pRetVal)
{
    if (pRetVal == NULL)
        return E_POINTER;

    SAFEARRAY *psa = SafeArrayCreateVector(VT_I4, 0, 2);
    if (!psa)
        return E_OUTOFMEMORY;
    
    // RuntimeID magic, use hwnd to differentiate providers of different windows
    int rId[] = { (int)canvasHwnd, SUMATRA_UIA_PAGE_RUNTIME_ID(pageNum) };
    for (LONG i = 0; i < 2; i++) {
        HRESULT hr = SafeArrayPutElement(psa, &i, (void*)&(rId[i]));
        CrashIf(FAILED(hr));
    }
    
    *pRetVal = psa;
    return S_OK;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::GetEmbeddedFragmentRoots(SAFEARRAY **pRetVal)
{
    if (pRetVal == NULL)
        return E_POINTER;

    // no other roots => return NULL
    *pRetVal = NULL;
    return S_OK;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::SetFocus(void)
{
    return S_OK;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::get_BoundingRectangle(struct UiaRect *pRetVal)
{
    if (pRetVal == NULL)
        return E_POINTER;

    if (released)
        return E_FAIL;

    // some engines might not support GetPageInfo
    const PageInfo* page = dm->GetPageInfo(pageNum);
    if (!page)
        return E_FAIL;

    RECT canvasRect;
    GetWindowRect(canvasHwnd, &canvasRect);

    pRetVal->left   = canvasRect.left + page->pageOnScreen.x;
    pRetVal->top    = canvasRect.top + page->pageOnScreen.y;
    pRetVal->width  = page->pageOnScreen.dx;
    pRetVal->height = page->pageOnScreen.dy;

    return S_OK;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::get_FragmentRoot(IRawElementProviderFragmentRoot **pRetVal)
{
    if (released)
        return E_FAIL;

    // let our parent to handle this
    return root->get_FragmentRoot(pRetVal);
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::GetPatternProvider(PATTERNID patternId,IUnknown **pRetVal)
{
    if (pRetVal == NULL)
        return E_POINTER;

    if (patternId == UIA_ValuePatternId) {
        *pRetVal = static_cast<IValueProvider*>(this);
        AddRef();
        return S_OK;
    }

    *pRetVal = NULL;
    return S_OK;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::GetPropertyValue(PROPERTYID propertyId,VARIANT *pRetVal)
{
    if (pRetVal == NULL)
        return E_POINTER;

    if (propertyId == UIA_NamePropertyId) {
        pRetVal->vt = VT_BSTR;
        pRetVal->bstrVal = SysAllocString(ScopedMem<WCHAR> (str::Format(L"Page %d",pageNum)));
        return S_OK;
    } else if (propertyId == UIA_IsValuePatternAvailablePropertyId) {
        pRetVal->vt = VT_BOOL;
        pRetVal->boolVal = TRUE;
        return S_OK;
    }

    pRetVal->vt = VT_EMPTY;
    return S_OK;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::get_HostRawElementProvider(IRawElementProviderSimple **pRetVal)
{
    if (pRetVal == NULL)
        return E_POINTER;
    *pRetVal = NULL;
    return S_OK;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::get_ProviderOptions(ProviderOptions *pRetVal)
{
    if (pRetVal == NULL)
        return E_POINTER;
    *pRetVal = ProviderOptions_ServerSideProvider;
    return S_OK;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::SetValue(LPCWSTR val)
{
    return E_ACCESSDENIED;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::get_Value(BSTR *pRetVal)
{
    if (pRetVal == NULL)
        return E_POINTER;
    if (released)
        return E_FAIL;

    const WCHAR * pageContent = dm->textCache->GetData(pageNum);
    if (!pageContent) {
        *pRetVal = NULL;
        return S_OK;
    }

    *pRetVal = SysAllocString(pageContent);
    return S_OK;
}

HRESULT STDMETHODCALLTYPE SumatraUIAutomationPageProvider::get_IsReadOnly(BOOL *pRetVal)
{
    if (pRetVal == NULL)
        return E_POINTER;

    *pRetVal = TRUE;
    return S_OK;
}
