/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "txExecutionState.h"
#include "txSingleNodeContext.h"
#include "txInstructions.h"
#include "txStylesheet.h"
#include "txVariableMap.h"
#include "txRtfHandler.h"
#include "txXSLTProcessor.h"
#include "txLog.h"
#include "txURIUtils.h"
#include "txXMLParser.h"

using mozilla::UniquePtr;
using mozilla::Unused;
using mozilla::WrapUnique;

const int32_t txExecutionState::kMaxRecursionDepth = 20000;

nsresult txLoadedDocumentsHash::init(const txXPathNode& aSource) {
  mSourceDocument = WrapUnique(txXPathNodeUtils::getOwnerDocument(aSource));

  nsAutoString baseURI;
  nsresult rv = txXPathNodeUtils::getBaseURI(*mSourceDocument, baseURI);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // Technically the hash holds documents, but we allow any node that we're
  // transforming from. In particular, the document() function uses this hash
  // and it can return the source document, but if we're transforming from a
  // document fragment (through
  // txMozillaXSLTProcessor::SetSourceContentModel/txMozillaXSLTProcessor::DoTransform)
  // or from another type of node (through
  // txMozillaXSLTProcessor::TransformToDocument or
  // txMozillaXSLTProcessor::TransformToFragment) it makes more sense to return
  // the real root of the source tree, which is the node where the transform
  // started.
  PutEntry(baseURI)->mDocument = WrapUnique(
      txXPathNativeNode::createXPathNode(txXPathNativeNode::getNode(aSource)));
  return NS_OK;
}

txLoadedDocumentsHash::~txLoadedDocumentsHash() {
  if (mSourceDocument) {
    nsAutoString baseURI;
    nsresult rv = txXPathNodeUtils::getBaseURI(*mSourceDocument, baseURI);
    if (NS_SUCCEEDED(rv)) {
      txLoadedDocumentEntry* entry = GetEntry(baseURI);
      if (entry) {
        delete entry->mDocument.release();
      }
    }
  }
}

txExecutionState::txExecutionState(txStylesheet* aStylesheet,
                                   bool aDisableLoads)
    : mOutputHandler(nullptr),
      mResultHandler(nullptr),
      mOutputHandlerFactory(nullptr),
      mStylesheet(aStylesheet),
      mNextInstruction(nullptr),
      mLocalVariables(nullptr),
      mRecursionDepth(0),
      mEvalContext(nullptr),
      mInitialEvalContext(nullptr),
      mGlobalParams(nullptr),
      mKeyHash(aStylesheet->getKeyMap()),
      mDisableLoads(aDisableLoads) {
  MOZ_COUNT_CTOR(txExecutionState);
}

txExecutionState::~txExecutionState() {
  MOZ_COUNT_DTOR(txExecutionState);

  delete mResultHandler;
  delete mLocalVariables;
  if (mEvalContext != mInitialEvalContext) {
    delete mEvalContext;
  }

  txStackIterator varsIter(&mLocalVarsStack);
  while (varsIter.hasNext()) {
    delete (txVariableMap*)varsIter.next();
  }

  txStackIterator contextIter(&mEvalContextStack);
  while (contextIter.hasNext()) {
    txIEvalContext* context = (txIEvalContext*)contextIter.next();
    if (context != mInitialEvalContext) {
      delete context;
    }
  }

  txStackIterator handlerIter(&mResultHandlerStack);
  while (handlerIter.hasNext()) {
    delete (txAXMLEventHandler*)handlerIter.next();
  }

  delete mInitialEvalContext;
}

nsresult txExecutionState::init(
    const txXPathNode& aNode,
    txOwningExpandedNameMap<txIGlobalParameter>* aGlobalParams) {
  nsresult rv = NS_OK;

  mGlobalParams = aGlobalParams;

  // Set up initial context
  mEvalContext = new txSingleNodeContext(aNode, this);
  mInitialEvalContext = mEvalContext;

  // Set up output and result-handler
  txAXMLEventHandler* handler;
  rv = mOutputHandlerFactory->createHandlerWith(mStylesheet->getOutputFormat(),
                                                &handler);
  NS_ENSURE_SUCCESS(rv, rv);

  mOutputHandler = handler;
  mResultHandler = handler;
  mOutputHandler->startDocument();

  // Set up loaded-documents-hash
  rv = mLoadedDocuments.init(aNode);
  NS_ENSURE_SUCCESS(rv, rv);

  // Init members
  rv = mKeyHash.init();
  NS_ENSURE_SUCCESS(rv, rv);

  mRecycler = new txResultRecycler;

  // The actual value here doesn't really matter since noone should use this
  // value. But lets put something errorlike in just in case
  mGlobalVarPlaceholderValue = new StringResult(u"Error"_ns, nullptr);

  // Initiate first instruction. This has to be done last since findTemplate
  // might use us.
  txStylesheet::ImportFrame* frame = 0;
  txExpandedName nullName;
  txInstruction* templ;
  rv =
      mStylesheet->findTemplate(aNode, nullName, this, nullptr, &templ, &frame);
  NS_ENSURE_SUCCESS(rv, rv);

  pushTemplateRule(frame, nullName, nullptr);

  return runTemplate(templ);
}

nsresult txExecutionState::end(nsresult aResult) {
  NS_ASSERTION(NS_FAILED(aResult) || mTemplateRules.Length() == 1,
               "Didn't clean up template rules properly");
  if (NS_SUCCEEDED(aResult)) {
    popTemplateRule();
  } else if (!mOutputHandler) {
    return NS_OK;
  }
  return mOutputHandler->endDocument(aResult);
}

void txExecutionState::popAndDeleteEvalContextUntil(txIEvalContext* aContext) {
  auto ctx = popEvalContext();
  while (ctx && ctx != aContext) {
    MOZ_RELEASE_ASSERT(ctx != mInitialEvalContext);
    delete ctx;
    ctx = popEvalContext();
  }
}

nsresult txExecutionState::getVariable(int32_t aNamespace, nsAtom* aLName,
                                       txAExprResult*& aResult) {
  nsresult rv = NS_OK;
  txExpandedName name(aNamespace, aLName);

  // look for a local variable
  if (mLocalVariables) {
    mLocalVariables->getVariable(name, &aResult);
    if (aResult) {
      return NS_OK;
    }
  }

  // look for an evaluated global variable
  mGlobalVariableValues.getVariable(name, &aResult);
  if (aResult) {
    if (aResult == mGlobalVarPlaceholderValue) {
      // XXX ErrorReport: cyclic variable-value
      NS_RELEASE(aResult);
      return NS_ERROR_XSLT_BAD_RECURSION;
    }
    return NS_OK;
  }

  // Is there perchance a global variable not evaluated yet?
  txStylesheet::GlobalVariable* var = mStylesheet->getGlobalVariable(name);
  if (!var) {
    // XXX ErrorReport: variable doesn't exist in this scope
    return NS_ERROR_FAILURE;
  }

  NS_ASSERTION((var->mExpr && !var->mFirstInstruction) ||
                   (!var->mExpr && var->mFirstInstruction),
               "global variable should have either instruction or expression");

  // Is this a stylesheet parameter that has a value?
  if (var->mIsParam && mGlobalParams) {
    txIGlobalParameter* param = mGlobalParams->get(name);
    if (param) {
      rv = param->getValue(&aResult);
      NS_ENSURE_SUCCESS(rv, rv);

      rv = mGlobalVariableValues.bindVariable(name, aResult);
      if (NS_FAILED(rv)) {
        NS_RELEASE(aResult);
        return rv;
      }

      return NS_OK;
    }
  }

  // Insert a placeholdervalue to protect against recursion
  rv = mGlobalVariableValues.bindVariable(name, mGlobalVarPlaceholderValue);
  NS_ENSURE_SUCCESS(rv, rv);

  // evaluate the global variable
  pushEvalContext(mInitialEvalContext);
  if (var->mExpr) {
    txVariableMap* oldVars = mLocalVariables;
    mLocalVariables = nullptr;
    rv = var->mExpr->evaluate(getEvalContext(), &aResult);
    mLocalVariables = oldVars;

    if (NS_FAILED(rv)) {
      popAndDeleteEvalContextUntil(mInitialEvalContext);
      return rv;
    }
  } else {
    pushResultHandler(new txRtfHandler);

    txInstruction* prevInstr = mNextInstruction;
    // set return to nullptr to stop execution
    mNextInstruction = nullptr;
    rv = runTemplate(var->mFirstInstruction.get());
    if (NS_FAILED(rv)) {
      popAndDeleteEvalContextUntil(mInitialEvalContext);
      return rv;
    }

    pushTemplateRule(nullptr, txExpandedName(), nullptr);
    rv = txXSLTProcessor::execute(*this);
    if (NS_FAILED(rv)) {
      popAndDeleteEvalContextUntil(mInitialEvalContext);
      return rv;
    }

    popTemplateRule();

    mNextInstruction = prevInstr;
    UniquePtr<txRtfHandler> rtfHandler(
        static_cast<txRtfHandler*>(popResultHandler()));
    rv = rtfHandler->getAsRTF(&aResult);
    if (NS_FAILED(rv)) {
      popAndDeleteEvalContextUntil(mInitialEvalContext);
      return rv;
    }
  }
  popEvalContext();

  // Remove the placeholder and insert the calculated value
  mGlobalVariableValues.removeVariable(name);
  rv = mGlobalVariableValues.bindVariable(name, aResult);
  if (NS_FAILED(rv)) {
    NS_RELEASE(aResult);

    return rv;
  }

  return NS_OK;
}

nsresult txExecutionState::isStripSpaceAllowed(const txXPathNode& aNode,
                                               bool& aAllowed) {
  return mStylesheet->isStripSpaceAllowed(aNode, this, aAllowed);
}

void* txExecutionState::getPrivateContext() { return this; }

txResultRecycler* txExecutionState::recycler() { return mRecycler; }

void txExecutionState::receiveError(const nsAString& aMsg, nsresult aRes) {
  // XXX implement me
}

void txExecutionState::pushEvalContext(txIEvalContext* aContext) {
  mEvalContextStack.push(mEvalContext);
  mEvalContext = aContext;
}

txIEvalContext* txExecutionState::popEvalContext() {
  txIEvalContext* prev = mEvalContext;
  mEvalContext = (txIEvalContext*)mEvalContextStack.pop();

  return prev;
}

void txExecutionState::pushBool(bool aBool) { mBoolStack.AppendElement(aBool); }

bool txExecutionState::popBool() {
  NS_ASSERTION(mBoolStack.Length(), "popping from empty stack");

  return mBoolStack.IsEmpty() ? false : mBoolStack.PopLastElement();
}

void txExecutionState::pushResultHandler(txAXMLEventHandler* aHandler) {
  mResultHandlerStack.push(mResultHandler);
  mResultHandler = aHandler;
}

txAXMLEventHandler* txExecutionState::popResultHandler() {
  txAXMLEventHandler* oldHandler = mResultHandler;
  mResultHandler = (txAXMLEventHandler*)mResultHandlerStack.pop();

  return oldHandler;
}

void txExecutionState::pushTemplateRule(txStylesheet::ImportFrame* aFrame,
                                        const txExpandedName& aMode,
                                        txParameterMap* aParams) {
  TemplateRule* rule = mTemplateRules.AppendElement();
  rule->mFrame = aFrame;
  rule->mModeNsId = aMode.mNamespaceID;
  rule->mModeLocalName = aMode.mLocalName;
  rule->mParams = aParams;
}

void txExecutionState::popTemplateRule() {
  MOZ_ASSERT(!mTemplateRules.IsEmpty(), "No rules to pop");
  mTemplateRules.RemoveLastElement();
}

txIEvalContext* txExecutionState::getEvalContext() { return mEvalContext; }

const txXPathNode* txExecutionState::retrieveDocument(const nsAString& aUri) {
  NS_ASSERTION(!aUri.Contains(char16_t('#')), "Remove the fragment.");

  if (mDisableLoads) {
    return nullptr;
  }

  MOZ_LOG(txLog::xslt, mozilla::LogLevel::Debug,
          ("Retrieve Document %s", NS_LossyConvertUTF16toASCII(aUri).get()));

  // try to get already loaded document
  txLoadedDocumentEntry* entry = mLoadedDocuments.PutEntry(aUri);
  if (!entry) {
    return nullptr;
  }

  if (!entry->mDocument && !entry->LoadingFailed()) {
    // open URI
    nsAutoString errMsg;
    // XXX we should get the loader from the actual node
    // triggering the load, but this will do for the time being
    entry->mLoadResult =
        txParseDocumentFromURI(aUri, *mLoadedDocuments.mSourceDocument, errMsg,
                               getter_Transfers(entry->mDocument));

    if (entry->LoadingFailed()) {
      receiveError(u"Couldn't load document '"_ns + aUri + u"': "_ns + errMsg,
                   entry->mLoadResult);
    }
  }

  return entry->mDocument.get();
}

nsresult txExecutionState::getKeyNodes(const txExpandedName& aKeyName,
                                       const txXPathNode& aRoot,
                                       const nsAString& aKeyValue,
                                       bool aIndexIfNotFound,
                                       txNodeSet** aResult) {
  return mKeyHash.getKeyNodes(aKeyName, aRoot, aKeyValue, aIndexIfNotFound,
                              *this, aResult);
}

txExecutionState::TemplateRule* txExecutionState::getCurrentTemplateRule() {
  MOZ_ASSERT(!mTemplateRules.IsEmpty(), "No current rule!");
  return &mTemplateRules[mTemplateRules.Length() - 1];
}

mozilla::Result<txInstruction*, nsresult>
txExecutionState::getNextInstruction() {
  if (mStopProcessing) {
    return mozilla::Err(NS_ERROR_FAILURE);
  }

  txInstruction* instr = mNextInstruction;
  if (instr) {
    mNextInstruction = instr->mNext.get();
  }

  return instr;
}

nsresult txExecutionState::runTemplate(txInstruction* aTemplate) {
  NS_ENSURE_TRUE(++mRecursionDepth < kMaxRecursionDepth,
                 NS_ERROR_XSLT_BAD_RECURSION);

  mLocalVarsStack.push(mLocalVariables);
  mReturnStack.push(mNextInstruction);

  mLocalVariables = nullptr;
  mNextInstruction = aTemplate;

  return NS_OK;
}

void txExecutionState::gotoInstruction(txInstruction* aNext) {
  mNextInstruction = aNext;
}

void txExecutionState::returnFromTemplate() {
  --mRecursionDepth;
  NS_ASSERTION(!mReturnStack.isEmpty() && !mLocalVarsStack.isEmpty(),
               "return or variable stack is empty");
  delete mLocalVariables;
  mNextInstruction = (txInstruction*)mReturnStack.pop();
  mLocalVariables = (txVariableMap*)mLocalVarsStack.pop();
}

nsresult txExecutionState::bindVariable(const txExpandedName& aName,
                                        txAExprResult* aValue) {
  if (!mLocalVariables) {
    mLocalVariables = new txVariableMap;
  }
  return mLocalVariables->bindVariable(aName, aValue);
}

void txExecutionState::removeVariable(const txExpandedName& aName) {
  mLocalVariables->removeVariable(aName);
}

void txExecutionState::pushParamMap(txParameterMap* aParams) {
  mParamStack.AppendElement(mTemplateParams.forget());
  mTemplateParams = aParams;
}

already_AddRefed<txParameterMap> txExecutionState::popParamMap() {
  RefPtr<txParameterMap> oldParams = std::move(mTemplateParams);
  mTemplateParams = mParamStack.PopLastElement();

  return oldParams.forget();
}