/*
 * Schema cache implementation
 *
 * Copyright 2007 Huw Davies
 * Copyright 2010 Adam Martinson for CodeWeavers
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#define COBJMACROS

#include "config.h"

#include <stdarg.h>
#include "windef.h"
#include "winbase.h"
#include "winuser.h"
#include "ole2.h"
#include "msxml6.h"

#include "wine/debug.h"

#include "msxml_private.h"

WINE_DEFAULT_DEBUG_CHANNEL(msxml);

/* We use a chained hashtable, which can hold any number of schemas
 * TODO: XDR schema support
 * TODO: grow/shrink hashtable depending on load factor
 * TODO: implement read-only where appropriate
 */

/* This is just the number of buckets, should be prime */
#define DEFAULT_HASHTABLE_SIZE 31

#ifdef HAVE_LIBXML2

#include <libxml/tree.h>
#include <libxml/xmlschemas.h>
#include <libxml/schemasInternals.h>
#include <libxml/hash.h>

static const xmlChar XSD_schema[] = "schema";
static const xmlChar XSD_nsURI[] = "http://www.w3.org/2001/XMLSchema";
static const xmlChar XDR_schema[] = "Schema";
static const xmlChar XDR_nsURI[] = "urn:schemas-microsoft-com:xml-data";

/* Supported Types:
 * msxml3 - XDR only
 * msxml4 - XDR & XSD
 * msxml5 - XDR & XSD
 * mxsml6 - XSD only
 */
typedef enum _SCHEMA_TYPE {
    SCHEMA_TYPE_INVALID,
    SCHEMA_TYPE_XDR,
    SCHEMA_TYPE_XSD
} SCHEMA_TYPE;

typedef struct _schema_cache
{
    const struct IXMLDOMSchemaCollection2Vtbl* lpVtbl;
    xmlHashTablePtr cache;
    LONG ref;
} schema_cache;

typedef struct _cache_entry
{
    SCHEMA_TYPE type;
    xmlSchemaPtr schema;
    xmlDocPtr doc;
    LONG ref;
} cache_entry;

typedef struct _cache_index_data
{
    LONG index;
    BSTR* out;
} cache_index_data;

static LONG cache_entry_add_ref(cache_entry* entry)
{
    LONG ref = InterlockedIncrement(&entry->ref);
    TRACE("%p new ref %d\n", entry, ref);
    return ref;
}

static LONG cache_entry_release(cache_entry* entry)
{
    LONG ref = InterlockedDecrement(&entry->ref);
    TRACE("%p new ref %d\n", entry, ref);

    if (ref == 0)
    {
        if (entry->type == SCHEMA_TYPE_XSD)
        {
            xmldoc_release(entry->doc);
            entry->schema->doc = NULL;
            xmlSchemaFree(entry->schema);
            heap_free(entry);
        }
        else /* SCHEMA_TYPE_XDR */
        {
            xmldoc_release(entry->doc);
            heap_free(entry);
        }
    }
    return ref;
}

static inline schema_cache* impl_from_IXMLDOMSchemaCollection2(IXMLDOMSchemaCollection2* iface)
{
    return (schema_cache*)((char*)iface - FIELD_OFFSET(schema_cache, lpVtbl));
}

static inline SCHEMA_TYPE schema_type_from_xmlDocPtr(xmlDocPtr schema)
{
    xmlNodePtr root;
    if (schema)
        root = xmlDocGetRootElement(schema);
    if (root && root->ns)
    {

        if (xmlStrEqual(root->name, XDR_schema) &&
            xmlStrEqual(root->ns->href, XDR_nsURI))
        {
            return SCHEMA_TYPE_XDR;
        }
        else if (xmlStrEqual(root->name, XSD_schema) &&
                 xmlStrEqual(root->ns->href, XSD_nsURI))
        {
            return SCHEMA_TYPE_XSD;
        }
    }
    return SCHEMA_TYPE_INVALID;
}

static cache_entry* cache_entry_from_url(char const* url)
{
    cache_entry* entry = heap_alloc(sizeof(cache_entry));
    xmlSchemaParserCtxtPtr spctx = xmlSchemaNewParserCtxt(url);
    entry->type = SCHEMA_TYPE_XSD;
    entry->ref = 0;
    if (spctx)
    {
        if((entry->schema = xmlSchemaParse(spctx)))
        {
            xmldoc_init(entry->schema->doc, &CLSID_DOMDocument40);
            entry->doc = entry->schema->doc;
            xmldoc_add_ref(entry->doc);
        }
        else
        {
            heap_free(entry);
            entry = NULL;
        }
        xmlSchemaFreeParserCtxt(spctx);
    }
    else
    {
        FIXME("schema for nsURI %s not found\n", wine_dbgstr_a(url));
        heap_free(entry);
        entry = NULL;
    }
    return entry;
}

static cache_entry* cache_entry_from_xsd_doc(xmlDocPtr doc)
{
    cache_entry* entry = heap_alloc(sizeof(cache_entry));
    xmlSchemaParserCtxtPtr spctx;
    xmlDocPtr new_doc = xmlCopyDoc(doc, 1);

    entry->type = SCHEMA_TYPE_XSD;
    entry->ref = 0;
    spctx = xmlSchemaNewDocParserCtxt(new_doc);

    if ((entry->schema = xmlSchemaParse(spctx)))
    {
        xmldoc_init(entry->schema->doc, &CLSID_DOMDocument40);
        entry->doc = entry->schema->doc;
        xmldoc_add_ref(entry->doc);
    }
    else
    {
        FIXME("failed to parse doc\n");
        xmlFreeDoc(new_doc);
        heap_free(entry);
        entry = NULL;
    }
    xmlSchemaFreeParserCtxt(spctx);
    return entry;
}

static cache_entry* cache_entry_from_xdr_doc(xmlDocPtr doc)
{
    cache_entry* entry = heap_alloc(sizeof(cache_entry));
    xmlDocPtr new_doc = xmlCopyDoc(doc, 1);

    FIXME("XDR schema support not implemented\n");
    entry->type = SCHEMA_TYPE_XDR;
    entry->ref = 0;
    entry->schema = NULL;
    entry->doc = new_doc;
    xmldoc_init(entry->doc, &CLSID_DOMDocument30);
    xmldoc_add_ref(entry->doc);

    return entry;
}

static HRESULT WINAPI schema_cache_QueryInterface(IXMLDOMSchemaCollection2* iface,
                                                  REFIID riid, void** ppvObject)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);

    TRACE("(%p)->(%s %p)\n", This, debugstr_guid(riid), ppvObject);

    if ( IsEqualIID(riid, &IID_IUnknown) ||
         IsEqualIID(riid, &IID_IDispatch) ||
         IsEqualIID(riid, &IID_IXMLDOMSchemaCollection) ||
         IsEqualIID(riid, &IID_IXMLDOMSchemaCollection2) )
    {
        *ppvObject = iface;
    }
    else
    {
        FIXME("interface %s not implemented\n", debugstr_guid(riid));
        return E_NOINTERFACE;
    }

    IXMLDOMSchemaCollection2_AddRef(iface);

    return S_OK;
}

static ULONG WINAPI schema_cache_AddRef(IXMLDOMSchemaCollection2* iface)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    LONG ref = InterlockedIncrement(&This->ref);
    TRACE("%p new ref %d\n", This, ref);
    return ref;
}

static void cache_free(void* data, xmlChar* name /* ignored */)
{
    cache_entry_release((cache_entry*)data);
}

static ULONG WINAPI schema_cache_Release(IXMLDOMSchemaCollection2* iface)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    LONG ref = InterlockedDecrement(&This->ref);
    TRACE("%p new ref %d\n", This, ref);

    if (ref == 0)
    {
        xmlHashFree(This->cache, cache_free);
        heap_free(This);
    }

    return ref;
}

static HRESULT WINAPI schema_cache_GetTypeInfoCount(IXMLDOMSchemaCollection2* iface,
                                                    UINT* pctinfo)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);

    TRACE("(%p)->(%p)\n", This, pctinfo);

    *pctinfo = 1;

    return S_OK;
}

static HRESULT WINAPI schema_cache_GetTypeInfo(IXMLDOMSchemaCollection2* iface,
                                               UINT iTInfo, LCID lcid, ITypeInfo** ppTInfo)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    HRESULT hr;

    TRACE("(%p)->(%u %u %p)\n", This, iTInfo, lcid, ppTInfo);

    hr = get_typeinfo(IXMLDOMSchemaCollection_tid, ppTInfo);

    return hr;
}

static HRESULT WINAPI schema_cache_GetIDsOfNames(IXMLDOMSchemaCollection2* iface,
                                                 REFIID riid, LPOLESTR* rgszNames,
                                                 UINT cNames, LCID lcid, DISPID* rgDispId)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    ITypeInfo* typeinfo;
    HRESULT hr;

    TRACE("(%p)->(%s %p %u %u %p)\n", This, debugstr_guid(riid), rgszNames, cNames,
          lcid, rgDispId);

    if(!rgszNames || cNames == 0 || !rgDispId)
        return E_INVALIDARG;

    hr = get_typeinfo(IXMLDOMSchemaCollection_tid, &typeinfo);
    if(SUCCEEDED(hr))
    {
        hr = ITypeInfo_GetIDsOfNames(typeinfo, rgszNames, cNames, rgDispId);
        ITypeInfo_Release(typeinfo);
    }

    return hr;
}

static HRESULT WINAPI schema_cache_Invoke(IXMLDOMSchemaCollection2* iface,
                                          DISPID dispIdMember, REFIID riid, LCID lcid,
                                          WORD wFlags, DISPPARAMS* pDispParams,
                                          VARIANT* pVarResult, EXCEPINFO* pExcepInfo,
                                          UINT* puArgErr)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    ITypeInfo* typeinfo;
    HRESULT hr;

    TRACE("(%p)->(%d %s %d %d %p %p %p %p)\n", This, dispIdMember, debugstr_guid(riid),
          lcid, wFlags, pDispParams, pVarResult, pExcepInfo, puArgErr);

    hr = get_typeinfo(IXMLDOMSchemaCollection_tid, &typeinfo);
    if(SUCCEEDED(hr))
    {
        hr = ITypeInfo_Invoke(typeinfo, &(This->lpVtbl), dispIdMember, wFlags, pDispParams,
                pVarResult, pExcepInfo, puArgErr);
        ITypeInfo_Release(typeinfo);
    }

    return hr;
}

static HRESULT WINAPI schema_cache_add(IXMLDOMSchemaCollection2* iface, BSTR uri, VARIANT var)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    xmlChar* name = xmlChar_from_wchar(uri);
    TRACE("(%p)->(%s, var(vt %x))\n", This, debugstr_w(uri), V_VT(&var));

    switch (V_VT(&var))
    {
        case VT_NULL:
            {
                xmlHashRemoveEntry(This->cache, name, cache_free);
            }
            break;

        case VT_BSTR:
            {
                xmlChar* url = xmlChar_from_wchar(V_BSTR(&var));
                cache_entry* entry = cache_entry_from_url((char const*)url);
                heap_free(url);

                if (entry)
                {
                    cache_entry_add_ref(entry);
                }
                else
                {
                    heap_free(name);
                    return E_FAIL;
                }

                xmlHashRemoveEntry(This->cache, name, cache_free);
                xmlHashAddEntry(This->cache, name, entry);
            }
            break;

        case VT_DISPATCH:
            {
                xmlDocPtr doc = NULL;
                cache_entry* entry;
                SCHEMA_TYPE type;
                IXMLDOMNode* domnode = NULL;
                IDispatch_QueryInterface(V_DISPATCH(&var), &IID_IXMLDOMNode, (void**)&domnode);

                if (domnode)
                    doc = xmlNodePtr_from_domnode(domnode, XML_DOCUMENT_NODE)->doc;

                if (!doc)
                {
                    IXMLDOMNode_Release(domnode);
                    heap_free(name);
                    return E_INVALIDARG;
                }
                type = schema_type_from_xmlDocPtr(doc);

                if (type == SCHEMA_TYPE_XSD)
                {
                    entry = cache_entry_from_xsd_doc(doc);
                }
                else if (type == SCHEMA_TYPE_XDR)
                {
                    entry = cache_entry_from_xdr_doc(doc);
                }
                else
                {
                    WARN("invalid schema!\n");
                    entry = NULL;
                }

                IXMLDOMNode_Release(domnode);

                if (entry)
                {
                    cache_entry_add_ref(entry);
                }
                else
                {
                    heap_free(name);
                    return E_FAIL;
                }

                xmlHashRemoveEntry(This->cache, name, cache_free);
                xmlHashAddEntry(This->cache, name, entry);
            }
            break;

        default:
            {
                heap_free(name);
                return E_INVALIDARG;
            }
    }
    heap_free(name);
    return S_OK;
}

static HRESULT WINAPI schema_cache_get(IXMLDOMSchemaCollection2* iface, BSTR uri,
                                       IXMLDOMNode** node)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    xmlChar* name;
    cache_entry* entry;
    TRACE("(%p)->(%s, %p)\n", This, wine_dbgstr_w(uri), node);

    if (!node)
        return E_POINTER;

    name = xmlChar_from_wchar(uri);
    entry = (cache_entry*) xmlHashLookup(This->cache, name);
    heap_free(name);

    /* TODO: this should be read-only */
    if (entry)
        return DOMDocument_create_from_xmldoc(entry->doc, (IXMLDOMDocument3**)node);

    *node = NULL;
    return S_OK;
}

static HRESULT WINAPI schema_cache_remove(IXMLDOMSchemaCollection2* iface, BSTR uri)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    xmlChar* name = xmlChar_from_wchar(uri);
    TRACE("(%p)->(%s)\n", This, wine_dbgstr_w(uri));

    xmlHashRemoveEntry(This->cache, name, cache_free);
    heap_free(name);
    return S_OK;
}

static HRESULT WINAPI schema_cache_get_length(IXMLDOMSchemaCollection2* iface, LONG* length)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    TRACE("(%p)->(%p)\n", This, length);

    if (!length)
        return E_POINTER;
    *length = xmlHashSize(This->cache);
    return S_OK;
}

static void cache_index(void* data /* ignored */, void* index, xmlChar* name)
{
    cache_index_data* index_data = (cache_index_data*)index;

    if (index_data->index-- == 0)
        *index_data->out = bstr_from_xmlChar(name);
}

static HRESULT WINAPI schema_cache_get_namespaceURI(IXMLDOMSchemaCollection2* iface,
                                                    LONG index, BSTR* len)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    cache_index_data data = {index,len};
    TRACE("(%p)->(%i, %p)\n", This, index, len);

    if (!len)
        return E_POINTER;
    *len = NULL;

    if (index >= xmlHashSize(This->cache))
        return E_FAIL;

    xmlHashScan(This->cache, cache_index, &data);
    return S_OK;
}

static void cache_copy(void* data, void* dest, xmlChar* name)
{
    schema_cache* This = (schema_cache*) dest;
    cache_entry* entry = (cache_entry*) data;

    if (xmlHashLookup(This->cache, name) == NULL)
    {
        cache_entry_add_ref(entry);
        xmlHashAddEntry(This->cache, name, entry);
    }
}

static HRESULT WINAPI schema_cache_addCollection(IXMLDOMSchemaCollection2* iface,
                                                 IXMLDOMSchemaCollection* otherCollection)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    schema_cache* That = impl_from_IXMLDOMSchemaCollection2((IXMLDOMSchemaCollection2*)otherCollection);
    TRACE("(%p)->(%p)\n", This, That);

    if (!otherCollection)
        return E_POINTER;

    /* TODO: detect errors while copying & return E_FAIL */
    xmlHashScan(That->cache, cache_copy, This);

    return S_OK;
}

static HRESULT WINAPI schema_cache_get__newEnum(IXMLDOMSchemaCollection2* iface,
                                                IUnknown** ppUnk)
{
    FIXME("stub\n");
    if (ppUnk)
        *ppUnk = NULL;
    return E_NOTIMPL;
}

static HRESULT WINAPI schema_cache_validate(IXMLDOMSchemaCollection2* iface)
{
    FIXME("stub\n");
    return E_NOTIMPL;
}

static HRESULT WINAPI schema_cache_put_validateOnLoad(IXMLDOMSchemaCollection2* iface,
                                                      VARIANT_BOOL validateOnLoad)
{
    FIXME("stub\n");
    return E_NOTIMPL;
}

static HRESULT WINAPI schema_cache_get_validateOnLoad(IXMLDOMSchemaCollection2* iface,
                                                      VARIANT_BOOL* validateOnLoad)
{
    FIXME("stub\n");
    return E_NOTIMPL;
}

static HRESULT WINAPI schema_cache_getSchema(IXMLDOMSchemaCollection2* iface,
                                             BSTR namespaceURI, ISchema** schema)
{
    FIXME("stub\n");
    if (schema)
        *schema = NULL;
    return E_NOTIMPL;
}

static HRESULT WINAPI schema_cache_getDeclaration(IXMLDOMSchemaCollection2* iface,
                                                  IXMLDOMNode* node, ISchemaItem** item)
{
    FIXME("stub\n");
    if (item)
        *item = NULL;
    return E_NOTIMPL;
}

static const struct IXMLDOMSchemaCollection2Vtbl schema_cache_vtbl =
{
    schema_cache_QueryInterface,
    schema_cache_AddRef,
    schema_cache_Release,
    schema_cache_GetTypeInfoCount,
    schema_cache_GetTypeInfo,
    schema_cache_GetIDsOfNames,
    schema_cache_Invoke,
    schema_cache_add,
    schema_cache_get,
    schema_cache_remove,
    schema_cache_get_length,
    schema_cache_get_namespaceURI,
    schema_cache_addCollection,
    schema_cache_get__newEnum,
    schema_cache_validate,
    schema_cache_put_validateOnLoad,
    schema_cache_get_validateOnLoad,
    schema_cache_getSchema,
    schema_cache_getDeclaration
};

static void LIBXML2_LOG_CALLBACK validate_error(void* ctx, char const* msg, ...)
{
    va_list ap;
    va_start(ap, msg);
    LIBXML2_CALLBACK_ERR(SchemaCache_validate_tree, msg, ap);
    va_end(ap);
}

static void LIBXML2_LOG_CALLBACK validate_warning(void* ctx, char const* msg, ...)
{
    va_list ap;
    va_start(ap, msg);
    LIBXML2_CALLBACK_WARN(SchemaCache_validate_tree, msg, ap);
    va_end(ap);
}

#ifdef HAVE_XMLSCHEMASSETVALIDSTRUCTUREDERRORS
static void validate_serror(void* ctx, xmlErrorPtr err)
{
    LIBXML2_CALLBACK_SERROR(SchemaCache_validate_tree, err);
}
#endif

HRESULT SchemaCache_validate_tree(IXMLDOMSchemaCollection2* iface, xmlNodePtr tree)
{
    schema_cache* This = impl_from_IXMLDOMSchemaCollection2(iface);
    cache_entry* entry;
    xmlChar const* ns = NULL;
    TRACE("(%p, %p)\n", This, tree);

    if (!tree)
        return E_POINTER;

    if ((xmlNodePtr)tree->doc == tree)
    {
        xmlNodePtr root = xmlDocGetRootElement(tree->doc);
        if (root && root->ns)
            ns = root->ns->href;
    }
    else if (tree->ns)
    {
        ns = tree->ns->href;
    }

    entry = xmlHashLookup(This->cache, ns);
    /* TODO: if the ns is not in the cache, and it's a URL,
     *       do we try to load from that? */
    if (entry)
    {
        if (entry->type == SCHEMA_TYPE_XDR)
        {
            FIXME("partial stub: XDR schema support not implemented\n");
            return S_OK;
        }
        else if (entry->type == SCHEMA_TYPE_XSD)
        {
            xmlSchemaValidCtxtPtr svctx;
            int err;
            /* TODO: if validateOnLoad property is false,
             *       we probably need to validate the schema here. */
            svctx = xmlSchemaNewValidCtxt(entry->schema);
            xmlSchemaSetValidErrors(svctx, validate_error, validate_warning, NULL);
#ifdef HAVE_XMLSCHEMASSETVALIDSTRUCTUREDERRORS
            xmlSchemaSetValidStructuredErrors(svctx, validate_serror, NULL);
#endif

            if ((xmlNodePtr)tree->doc == tree)
                err = xmlSchemaValidateDoc(svctx, (xmlDocPtr)tree);
            else
                err = xmlSchemaValidateOneElement(svctx, tree);

            xmlSchemaFreeValidCtxt(svctx);
            return err? S_FALSE : S_OK;
        }
    }

    return E_FAIL;
}

HRESULT SchemaCache_create(IUnknown* pUnkOuter, void** ppObj)
{
    schema_cache* This = heap_alloc(sizeof(schema_cache));
    if (!This)
        return E_OUTOFMEMORY;

    This->lpVtbl = &schema_cache_vtbl;
    This->cache = xmlHashCreate(DEFAULT_HASHTABLE_SIZE);
    This->ref = 1;

    *ppObj = &This->lpVtbl;
    return S_OK;
}

#else

HRESULT SchemaCache_create(IUnknown* pUnkOuter, void** ppObj)
{
    MESSAGE("This program tried to use a SchemaCache object, but\n"
            "libxml2 support was not present at compile time.\n");
    return E_NOTIMPL;
}

#endif