/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License.  You may obtain a copy of the License at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is Mozilla Communicator client code.
 *
 * The Initial Developer of the Original Code is Netscape Communications
 * Corporation.  Portions created by Netscape are Copyright (C) 1998
 * Netscape Communications Corporation.  All Rights Reserved.
 */
#include "nsWebCrawler.h"
#include "nsViewerApp.h"
#include "nsIWebShell.h"
#include "nsIBrowserWindow.h"
#include "nsIContentViewer.h"
#include "nsIDocumentViewer.h"
#include "nsIDocument.h"
#include "nsIContent.h"
#include "nsIPresShell.h"
#include "nsIPresContext.h"
#include "nsIFrame.h"
#include "nsIURL.h"
#include "nsITimer.h"
#include "nsIAtom.h"
#include "nsRect.h"
#include "plhash.h"

static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
static NS_DEFINE_IID(kIDocumentViewerIID, NS_IDOCUMENT_VIEWER_IID);

static PLHashNumber
HashKey(nsIAtom* key)
{
  return (PLHashNumber) key;
}

static PRIntn
CompareKeys(nsIAtom* key1, nsIAtom* key2)
{
  return key1 == key2;
}

class AtomHashTable {
public:
  AtomHashTable();
  ~AtomHashTable();

  void* Get(nsIAtom* aKey);
  void* Put(nsIAtom* aKey, void* aValue);
  void* Remove(nsIAtom* aKey);

protected:
  PLHashTable* mTable;
};

AtomHashTable::AtomHashTable()
{
  mTable = PL_NewHashTable(8, (PLHashFunction) HashKey,
                           (PLHashComparator) CompareKeys,
                           (PLHashComparator) nsnull,
                           nsnull, nsnull);
}

static PR_CALLBACK PRIntn
DestroyEntry(PLHashEntry *he, PRIntn i, void *arg)
{
  ((nsIAtom*)he->key)->Release();
  return HT_ENUMERATE_NEXT;
}

AtomHashTable::~AtomHashTable()
{
  PL_HashTableEnumerateEntries(mTable, DestroyEntry, 0);
  PL_HashTableDestroy(mTable);
}

/**
 * Get the data associated with a Atom.
 */
void*
AtomHashTable::Get(nsIAtom* aKey)
{
  PRInt32 hashCode = (PRInt32) aKey;
  PLHashEntry** hep = PL_HashTableRawLookup(mTable, hashCode, aKey);
  PLHashEntry* he = *hep;
  if (nsnull != he) {
    return he->value;
  }
  return nsnull;
}

/**
 * Create an association between a Atom and some data. This call
 * returns an old association if there was one (or nsnull if there
 * wasn't).
 */
void*
AtomHashTable::Put(nsIAtom* aKey, void* aData)
{
  PRInt32 hashCode = (PRInt32) aKey;
  PLHashEntry** hep = PL_HashTableRawLookup(mTable, hashCode, aKey);
  PLHashEntry* he = *hep;
  if (nsnull != he) {
    void* oldValue = he->value;
    he->value = aData;
    return oldValue;
  }
  NS_ADDREF(aKey);
  PL_HashTableRawAdd(mTable, hep, hashCode, aKey, aData);
  return nsnull;
}

/**
 * Remove an association between a Atom and it's data. This returns
 * the old associated data.
 */
void*
AtomHashTable::Remove(nsIAtom* aKey)
{
  PRInt32 hashCode = (PRInt32) aKey;
  PLHashEntry** hep = PL_HashTableRawLookup(mTable, hashCode, aKey);
  PLHashEntry* he = *hep;
  void* oldValue = nsnull;
  if (nsnull != he) {
    oldValue = he->value;
    PL_HashTableRawRemove(mTable, hep, he);
  }
  return oldValue;
}

//----------------------------------------------------------------------

nsWebCrawler::nsWebCrawler(nsViewerApp* aViewer)
{
  NS_INIT_REFCNT();

  mBrowser = nsnull;
  mViewer = aViewer;
  NS_IF_ADDREF(aViewer);
  mTimer = nsnull;
  mCrawl = PR_FALSE;
  mJiggleLayout = PR_FALSE;
  mFilter = nsnull;
  mOutputDir= nsnull;
  mPostExit = PR_FALSE;
  mDelay = 0;
  mMaxPages = -1;
  mRecord = nsnull;
  mLinkTag = NS_NewAtom("A");
  mFrameTag = NS_NewAtom("FRAME");
  mIFrameTag = NS_NewAtom("IFRAME");
  mVisited = new AtomHashTable();
}

static void FreeStrings(nsVoidArray& aArray)
{
  PRInt32 i, n = aArray.Count();
  for (i = 0; i < n; i++) {
    nsString* s = (nsString*) aArray.ElementAt(i);
    delete s;
  }
  aArray.Clear();
}

nsWebCrawler::~nsWebCrawler()
{
  FreeStrings(mSafeDomains);
  FreeStrings(mAvoidDomains);
  NS_IF_RELEASE(mBrowser);
  NS_IF_RELEASE(mViewer);
  NS_IF_RELEASE(mTimer);
  NS_IF_RELEASE(mLinkTag);
  NS_IF_RELEASE(mFrameTag);
  NS_IF_RELEASE(mIFrameTag);
  delete mVisited;
  if (nsnull!=mFilter)
    delete mFilter;
  if (nsnull!=mOutputDir)
    delete mOutputDir;
}

NS_IMPL_ISUPPORTS(nsWebCrawler, kISupportsIID)

NS_IMETHODIMP
nsWebCrawler::OnStartBinding(nsIURL* aURL, const char *aContentType)
{
  return NS_OK;
}

NS_IMETHODIMP
nsWebCrawler::OnProgress(nsIURL* aURL, PRInt32 aProgress, PRInt32 aProgressMax)
{
  return NS_OK;
}

NS_IMETHODIMP
nsWebCrawler::OnStatus(nsIURL* aURL, const nsString& aMsg)
{
  return NS_OK;
}

NS_IMETHODIMP
nsWebCrawler::OnStopBinding(nsIURL* aURL, PRInt32 status, const nsString& aMsg)
{
  if (nsnull!=mFilter)
  {
    nsIPresShell* shell = GetPresShell();
    if (nsnull != shell) {
      nsIFrame* root = shell->GetRootFrame();
      if (nsnull != root) {
        nsIListFilter *filter = nsIFrame::GetFilter(mFilter);
        if (nsnull!=mOutputDir)
        {
          FILE *fp = GetOutputFile(aURL);
          if (nsnull!=fp)
          {
            root->List(fp, 0, filter);
            fclose(fp);
          }
          else
            printf("could not open output file for %s\n", aURL->GetFile());
        }
        else
          root->List(stdout, 0, filter);
      }
      NS_RELEASE(shell);
    }
    else {
      fputs("null pres shell\n", stdout);
    }
  }

  if (mJiggleLayout) {
    nsRect r;
    mBrowser->GetBounds(r);
    nscoord oldWidth = r.width;
    while (r.width > 100) {
      r.width -= 10;
      mBrowser->SizeTo(r.width, r.height);
    }
    while (r.width < oldWidth) {
      r.width += 10;
      mBrowser->SizeTo(r.width, r.height);
    }
  }

  if (mCrawl) {
    FindMoreURLs();
  }

  if (0 == mDelay) {
    LoadNextURL();
  }

  return NS_OK;
}

FILE * nsWebCrawler::GetOutputFile(nsIURL *aURL)
{
  static const char kDefaultOutputFileName[] = "test.txt";   // the default
  FILE *result = nsnull;
  if (nsnull!=aURL)
  {
    char *inputFileName;
    nsAutoString inputFileFullPath(aURL->GetFile());
    PRInt32 fileNameOffset = inputFileFullPath.RFind('/');
    if (-1==fileNameOffset)
    {
      inputFileName = new char[strlen(kDefaultOutputFileName) + 1];
      strcpy (inputFileName, kDefaultOutputFileName);
    }
    else
    {
      PRInt32 len = inputFileFullPath.Length() - fileNameOffset;
      inputFileName = new char[len + 1];
      char *c = inputFileName;
      for (PRInt32 i=fileNameOffset+1; i<fileNameOffset+len; i++)
      {
        *c = inputFileFullPath[i]; 
        c++;
      }
      inputFileName[len-1]=nsnull;
    }
    nsAutoString outputFileName(*mOutputDir);
    outputFileName += inputFileName;
    PRInt32 bufLen = outputFileName.Length()+1;
    char *buf = new char[bufLen+1];
    outputFileName.ToCString(buf, bufLen);
    result = fopen(buf, "wt");
    delete [] buf;
    delete [] inputFileName;
  }
  return result;
}

void
nsWebCrawler::AddURL(const nsString& aURL)
{
  nsString* s = new nsString(aURL);
  mPendingURLs.AppendElement(s);
}

void
nsWebCrawler::AddSafeDomain(const nsString& aDomain)
{
  nsString* s = new nsString(aDomain);
  mSafeDomains.AppendElement(s);
}

void
nsWebCrawler::AddAvoidDomain(const nsString& aDomain)
{
  nsString* s = new nsString(aDomain);
  mAvoidDomains.AppendElement(s);
}

void 
nsWebCrawler::SetFilter(const nsString& aFilter)
{
  if (nsnull==mFilter)
    mFilter = new nsString(aFilter);
  else
    (*mFilter) = aFilter;
}

void 
nsWebCrawler::SetOutputDir(const nsString& aOutputDir)
{
  if (nsnull==mOutputDir)
    mOutputDir = new nsString(aOutputDir);
  else
    (*mOutputDir) = aOutputDir;
}

void
nsWebCrawler::Start()
{
  // Enable observing each URL load...
  nsIWebShell* shell = nsnull;
  mBrowser->GetWebShell(shell);
  shell->SetObserver((nsIStreamObserver*)this);

  LoadNextURL();
}

void
nsWebCrawler::EnableCrawler()
{
  mCrawl = PR_TRUE;
}

static const unsigned char kLowerLookup[256] = {
  0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,
  16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,
  32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,
  48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,
  64,
    97,98,99,100,101,102,103,104,105,106,107,108,109,
    110,111,112,113,114,115,116,117,118,119,120,121,122,

   91, 92, 93, 94, 95, 96, 97, 98, 99,100,101,102,103,104,105,106,107,108,109,110,111,
  112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,

  128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
  144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,
  160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,
  176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,
  192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,
  208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,
  224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,
  240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255
};

static PRBool
EndsWith(const nsString& aDomain, const char* aHost, PRInt32 aHostLen)
{
  PRInt32 slen = aDomain.Length();
  if (slen < aHostLen) {
    return PR_FALSE;
  }
  const PRUnichar* uc = aDomain.GetUnicode();
  uc += slen - aHostLen;
  const PRUnichar* end = uc + aHostLen;
  while (uc < end) {
    unsigned char uch = (unsigned char) ((*uc++) & 0xff);
    unsigned char ch = (unsigned char) ((*aHost++) & 0xff);
    if (kLowerLookup[uch] != kLowerLookup[ch]) {
      return PR_FALSE;
    }
  }
  return PR_TRUE;
}

static PRBool
StartsWith(const nsString& s1, const char* s2)
{
  PRInt32 s1len = s1.Length();
  PRInt32 s2len = strlen(s2);
  if (s1len < s2len) {
    return PR_FALSE;
  }
  const PRUnichar* uc = s1.GetUnicode();
  const PRUnichar* end = uc + s2len;
  while (uc < end) {
    unsigned char uch = (unsigned char) ((*uc++) & 0xff);
    unsigned char ch = (unsigned char) ((*s2++) & 0xff);
    if (kLowerLookup[uch] != kLowerLookup[ch]) {
      return PR_FALSE;
    }
  }
  return PR_TRUE;
}

PRBool
nsWebCrawler::OkToLoad(const nsString& aURLSpec)
{
  if (!StartsWith(aURLSpec, "http:") && !StartsWith(aURLSpec, "ftp:") &&
      !StartsWith(aURLSpec, "file:") &&
      !StartsWith(aURLSpec, "resource:")) {
    return PR_FALSE;
  }

  PRBool ok = PR_TRUE;
  nsIURL* url;
  nsresult rv = NS_NewURL(&url, aURLSpec);
  if (NS_OK == rv) {
    const char* host = url->GetHost();
    if (nsnull != host) {
      PRInt32 hostlen = PL_strlen(host);

      // Check domains to avoid
      PRInt32 i, n = mAvoidDomains.Count();
      for (i = 0; i < n; i++) {
        nsString* s = (nsString*) mAvoidDomains.ElementAt(i);
        if (s && EndsWith(*s, host, hostlen)) {
          printf("Avoiding '");
          fputs(aURLSpec, stdout);
          printf("'\n");
          return PR_FALSE;
        }
      }

      // Check domains to stay within
      n = mSafeDomains.Count();
      if (n == 0) {
        // If we don't care then all the domains that we aren't
        // avoiding are OK
        return PR_TRUE;
      }
      for (i = 0; i < n; i++) {
        nsString* s = (nsString*) mSafeDomains.ElementAt(i);
        if (s && EndsWith(*s, host, hostlen)) {
          return PR_TRUE;
        }
      }
      ok = PR_FALSE;
    }
    NS_RELEASE(url);
  }
  return ok;
}

void
nsWebCrawler::RecordLoadedURL(const nsString& aURL)
{
  if (nsnull != mRecord) {
    fputs(aURL, mRecord);
    fputs("\n", mRecord);
    fflush(mRecord);
  }
}

void
nsWebCrawler::FindURLsIn(nsIDocument* aDocument, nsIContent* aNode)
{
  nsIAtom* atom;
  aNode->GetTag(atom);
  if ((atom == mLinkTag) || (atom == mFrameTag) || (atom == mIFrameTag)) {
    // Get absolute url that tag targets
    nsAutoString base, src, absURLSpec;
    if (atom == mLinkTag) {
      aNode->GetAttribute("href", src);
    }
    else {
      aNode->GetAttribute("src", src);
    }
    aNode->GetAttribute("_base_href", base);/* XXX not public knowledge! */
    nsIURL* docURL = aDocument->GetDocumentURL();
    nsresult rv = NS_MakeAbsoluteURL(docURL, base, src, absURLSpec);
    if (NS_OK == rv) {
      nsIAtom* urlAtom = NS_NewAtom(absURLSpec);
      if (0 == mVisited->Get(urlAtom)) {
        // Remember the URL as visited so that we don't go there again
        mVisited->Put(urlAtom, "visited");
        if (OkToLoad(absURLSpec)) {
          mPendingURLs.AppendElement(new nsString(absURLSpec));
          printf("Adding '");
          fputs(absURLSpec, stdout);
          printf("'\n");
        }
        else {
          printf("Skipping '");
          fputs(absURLSpec, stdout);
          printf("'\n");
        }
      }
      else {
        printf("Already visited '");
        fputs(absURLSpec, stdout);
        printf("'\n");
      }
      NS_RELEASE(urlAtom);
    }
    NS_RELEASE(docURL);
  }
  NS_IF_RELEASE(atom);
  PRBool canHaveKids;
  aNode->CanContainChildren(canHaveKids);
  if (canHaveKids) {
    PRInt32 i, n;
    aNode->ChildCount(n);
    for (i = 0; i < n; i++) {
      nsIContent* kid;
      aNode->ChildAt(i, kid);
      if (nsnull != kid) {
        FindURLsIn(aDocument, kid);
        NS_RELEASE(kid);
      }
    }
  }
}

void
nsWebCrawler::FindMoreURLs()
{
  nsIWebShell* shell = nsnull;
  mBrowser->GetWebShell(shell);
  if (nsnull != shell) {
    nsIContentViewer* cv = nsnull;
    shell->GetContentViewer(cv);
    if (nsnull != cv) {
      nsIDocumentViewer* docv = nsnull;
      cv->QueryInterface(kIDocumentViewerIID, (void**) &docv);
      if (nsnull != docv) {
        nsIDocument* doc = nsnull;
        docv->GetDocument(doc);
        if (nsnull != doc) {
          nsIContent* root;
          root = doc->GetRootContent();
          if (nsnull != root) {
            FindURLsIn(doc, root);
            NS_RELEASE(root);
          }
          NS_RELEASE(doc);
        }
        NS_RELEASE(docv);
      }
      NS_RELEASE(cv);
    }
    NS_RELEASE(shell);
  }
}

static void
TimerCallBack(nsITimer *aTimer, void *aClosure)
{
  nsWebCrawler* wc = (nsWebCrawler*) aClosure;
  wc->LoadNextURL();
}

void
nsWebCrawler::LoadNextURL()
{
  if (0 != mDelay) {
    NS_NewTimer(&mTimer);
    mTimer->Init(TimerCallBack, (void *)this, mDelay * 1000);
  }

  if ((mMaxPages < 0) || (mMaxPages > 0)) {
    while (0 != mPendingURLs.Count()) {
      nsString* url = (nsString*) mPendingURLs.ElementAt(0);
      mPendingURLs.RemoveElementAt(0);
      if (OkToLoad(*url)) {
        RecordLoadedURL(*url);
        mBrowser->LoadURL(*url);
        if (mMaxPages > 0) {
          --mMaxPages;
        }
        return;
      }
    }
  }

  if (nsnull != mRecord) {
    fclose(mRecord);
    mRecord = nsnull;
  }

  if (mPostExit) {
    mViewer->Exit();
  }
}

nsIPresShell*
nsWebCrawler::GetPresShell()
{
  nsIWebShell* webShell;
  mBrowser->GetWebShell(webShell);
  nsIPresShell* shell = nsnull;
  if (nsnull != webShell) {
    nsIContentViewer* cv = nsnull;
    webShell->GetContentViewer(cv);
    if (nsnull != cv) {
      nsIDocumentViewer* docv = nsnull;
      cv->QueryInterface(kIDocumentViewerIID, (void**) &docv);
      if (nsnull != docv) {
        nsIPresContext* cx;
        docv->GetPresContext(cx);
        if (nsnull != cx) {
          shell = cx->GetShell();
          NS_RELEASE(cx);
        }
        NS_RELEASE(docv);
      }
      NS_RELEASE(cv);
    }
    NS_RELEASE(webShell);
  }
  return shell;
}