//
// WordList.cc
//
// WordList: Interface to the word database. Previously, this wrote to 
//           a temporary text file. Now it writes directly to the 
//           word database. 
//           NOTE: Some code previously attempted to directly read from 
//           the word db. This will no longer work, so it's preferred to 
//           use the access methods here.
//	     Configuration parameter used:
//           wordlist_extend
//           wordlist_verbose 1 walk logic
//           wordlist_verbose 2 walk logic details
//           wordlist_verbose 3 walk logic lots of details
//
// Part of the ht://Dig package   <http://www.htdig.org/>
// Copyright (c) 1999, 2000 The ht://Dig Group
// For copyright details, see the file COPYING in your distribution
// or the GNU General Public License version 2 or later
// <http://www.gnu.org/copyleft/gpl.html>
//
// $Id: WordList.cc,v 1.6.2.40 2000/10/10 03:15:44 ghutchis Exp $
//

#ifdef HAVE_CONFIG_H
#include "htconfig.h"
#endif /* HAVE_CONFIG_H */

#include "WordList.h"
#include "WordReference.h"
#include "WordRecord.h"
#include "WordType.h"
#include "WordStat.h"
#include "Configuration.h"
#include "htString.h"
#include "HtPack.h"
#include "HtTime.h"
#include "WordDBCompress.h"

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>

// *****************************************************************************
//
WordList::WordList(const Configuration& config_arg) :
  wtype(config_arg),
  config(config_arg)
{
  // The database itself hasn't been opened yet
  isopen = 0;
  isread = 0;
  extended = config.Boolean("wordlist_extend");
  verbose =  config.Value("wordlist_verbose");
  compressor = 0;
}

// *****************************************************************************
//
WordList::~WordList()
{
  Close();
}

// *****************************************************************************
//
int WordList::Open(const String& filename, int mode)
{
  int usecompress=0;

  db.set_bt_compare(word_db_cmp);

  if(config.Value("wordlist_page_size", 0))
    db.set_pagesize(config.Value("wordlist_page_size"));

  if(config.Boolean("wordlist_compress") == 1) {
    usecompress = DB_COMPRESS;
    WordDBCompress* compressor = new WordDBCompress();
    //      compressor->debug = config.Value("wordlist_compress_debug");
    SetCompressor(compressor);
    db.CmprInfo(compressor->CmprInfo());
  }

  int flags = (mode & O_RDWR) ? DB_CREATE : DB_RDONLY;
  if(mode & O_TRUNC) {
    if(flags == DB_CREATE)
      flags |= DB_TRUNCATE;
    else
      fprintf(stderr, "WordList::Open: O_TRUNC | O_RDONLY is meaningless\n");
  }
  flags |= usecompress;

  int ret = db.Open(filename, DB_BTREE, flags, 0666) == 0 ? OK : NOTOK;

  isread = mode & O_RDONLY;
  isopen = 1;

  return ret;
}

// *****************************************************************************
//
int WordList::Close()
{
  if(isopen) {
    if(db.Close() != 0) return NOTOK;
    isopen = 0;
    isread = 0;
  }

  {
    WordDBCompress* compressor = GetCompressor();
    if(compressor) {
      delete compressor;
      SetCompressor(0);
    }
  }

  return OK;
}

// ****************************************************************************
//
int WordList::Put(const WordReference& arg, int flags)
{
  if (arg.Key().GetWord().length() == 0) {
    fprintf(stderr, "WordList::Put(%s) word is zero length\n", (char*)arg.Get());
    return NOTOK;
  }
  if (!arg.Key().Filled()) {
    fprintf(stderr, "WordList::Put(%s) key is not fully defined\n", (char*)arg.Get());
    return NOTOK;
  }

  WordReference	wordRef(arg);
  String 	word = wordRef.Key().GetWord();
  if(wtype.Normalize(word) & WORD_NORMALIZE_NOTOK)
    return NOTOK;
  wordRef.Key().SetWord(word);

  //
  // The two case could be grouped in a more compact way.
  // However, the resources consumption difference between
  // a Put(DB_NOOVERWRITE) and Put(0) is huge (the first is 75% 
  // slower than the second). Check the db_put sources for the
  // explanation.
  //
  int ret = NOTOK;
  if(flags) {
    //
    // First attempt tells us if the key exists. If it
    // does not we just increment the reference count.
    // Otherwise, and only if flags does not contain DB_NOOVERWRITE,
    // we override the key/record pair.
    //
    int error;
    if((error = db.Put(wordRef, DB_NOOVERWRITE)) != 0) {
      if(error == DB_KEYEXIST && flags == 0)
	ret = db.Put(wordRef, 0) == 0 ? OK : NOTOK;
    } else {
      ret = Ref(wordRef);
    }
  } else {
    if((ret = db.Put(wordRef, 0)) == 0)
      ret = Ref(wordRef);
  }

  return ret;
}


// *****************************************************************************
//
List *WordList::operator [] (const WordReference& wordRef)
{
  return Collect(wordRef);
}

// *****************************************************************************
//
List *WordList::Prefix (const WordReference& prefix)
{
  WordReference prefix2(prefix);
  prefix2.Key().UndefinedWordSuffix();
  return Collect(prefix2);
}

// *****************************************************************************
//
List *WordList::WordRefs()
{
  return Collect(WordReference());
}

// *****************************************************************************
//
List *WordList::Collect(const WordReference& wordRef)
{
  WordCursor *search = Cursor(wordRef.Key(), HTDIG_WORDLIST_COLLECTOR);
  if(search->Walk() != OK) return 0;
  List* result = search->GetResults();
  delete search;
  return result;
}

// *****************************************************************************
//
// Callback data dedicated to Dump and dump_word communication
//
class DeleteWordData : public Object
{
public:
  DeleteWordData() { count = 0; }

  int count;
};

// *****************************************************************************
//
//
static int delete_word(WordList *words, WordDBCursor &cursor, const WordReference *word, Object &data)
{
  if(words->Delete(cursor) == 0) {
    words->Unref(*word);
    ((DeleteWordData&)data).count++;
    return OK;
  } else {
    fprintf(stderr, "WordList delete_word: deleting %s failed\n", (char*)word->Get());
    return NOTOK;
  }
}

// *****************************************************************************
// 
// Delete all records matching wordRef, return the number of 
// deleted records.
//
int WordList::WalkDelete(const WordReference& wordRef)
{
  DeleteWordData data;
  WordCursor *description = Cursor(wordRef.Key(), delete_word, &data);
  description->Walk();
  delete description;
  return data.count;
}

// *****************************************************************************
//
//
List *WordList::Words()
{
  List		*list = 0;
  String		key;
  String		record;
  WordReference	lastWord;
  WordDBCursor		cursor;

  if(cursor.Open(db.db) != 0) return 0;

  //
  // Move past the first word count record
  //
  const WordReference& last = WordStat::Last();
  last.Pack(key, record);
  if(cursor.Get(key, record, DB_SET_RANGE) != 0)
    return 0;
  list = new List;
  do {
    WordReference	wordRef(key, record);
    if(lastWord.Key().GetWord().empty() ||
       wordRef.Key().GetWord() != lastWord.Key().GetWord()) 
      {
	list->Add(new String(wordRef.Key().GetWord()));
	lastWord = wordRef;
      }
  } while (cursor.Get(key, record, DB_NEXT) == 0);
    
  return list;
}

// *****************************************************************************
//
// Returns the reference count for word in <count> arg
//
int WordList::Noccurrence(const WordKey& key, unsigned int& noccurrence) const
{
  noccurrence = 0;
  WordStat stat(key.GetWord());
  int ret;
  if((ret = db.Get(stat)) != 0) {
    if(ret != DB_NOTFOUND)
      return NOTOK;
  } else {
    noccurrence = stat.Noccurrence();
  }

  return OK;
}

// *****************************************************************************
//
// Increment reference count for wordRef
//
int WordList::Ref(const WordReference& wordRef)
{
  if(!extended) return OK;

  WordStat stat(wordRef.Key().GetWord());
  int ret;
  if((ret = db.Get(stat)) != 0 && ret != DB_NOTFOUND)
    return NOTOK;

  stat.Noccurrence()++;

  return db.Put(stat, 0) == 0 ? OK : NOTOK;
}

// *****************************************************************************
//
// Decrement reference count for wordRef
//
int WordList::Unref(const WordReference& wordRef)
{
  if(!extended) return OK;

  WordStat stat(wordRef.Key().GetWord());
  int ret;
  if((ret = db.Get(stat)) != 0) {
    if(ret == DB_NOTFOUND)
      fprintf(stderr, "WordList::Unref(%s) Unref on non existing word occurrence\n", (char*)wordRef.Get());
    return NOTOK;
  }

  if(stat.Noccurrence() == 0) {
    fprintf(stderr, "WordList::Unref(%s) Unref on 0 occurrences word\n", (char*)wordRef.Get());
    return NOTOK;
  }
  stat.Noccurrence()--;

  if(stat.Noccurrence() > 0) {
    ret = db.Put(stat, 0) == 0 ? OK : NOTOK;
  } else
    ret = db.Del(stat) == 0 ? OK : NOTOK;
  return ret;
}


// *****************************************************************************
//
// streaming operators for ascii dumping and reading a list
class FileOutData : public Object
{
public:
  FILE* f;
  FileOutData(FILE* f_arg) : f(f_arg) { }
};

// *****************************************************************************
//
static int
wordlist_walk_callback_file_out(WordList *, WordDBCursor& , const WordReference *word, Object &data)
{
  fprintf(((FileOutData&)data).f, "%s\n", (char*)word->Get());
  return OK;
}

// *****************************************************************************
//
int 
WordList::Write(FILE* f)
{
  WordKey empty;
  FileOutData data(f);
  WordCursor *description = Cursor(empty, wordlist_walk_callback_file_out, (Object *)&data);
  description->Walk();
  delete description;
  return 0;
}

// *****************************************************************************
//
int 
WordList::Read(FILE* f)
{
  WordReference word;
#define WORD_BUFFER_SIZE	1024
  char buffer[WORD_BUFFER_SIZE + 1];
  String line;
  int line_number = 0;
  int inserted = 0;

  while(fgets(buffer, WORD_BUFFER_SIZE, f)) {
    line_number++;
    int buffer_length = strlen(buffer);
    int eol = buffer[buffer_length - 1] == '\n';

    if(eol) buffer[--buffer_length] = '\0';
    
    line.append(buffer, buffer_length);
    //
    // Join big lines
    //
    if(!eol) continue;
    //
    // If line ends with a \ continue
    //
    if(line.last() == '\\') {
      line.chop(1);
      continue;
    }
      
    if(!line.empty()) {
      if(word.Set(line) != OK) {
	fprintf(stderr, "WordList::Read: line %d : %s\n", line_number, (char*)line);
	fprintf(stderr, " cannot build WordReference (ignored)\n");
      } else {
	if(Insert(word) != OK) {
	  fprintf(stderr, "WordList::Read: line %d : %s\n", line_number, (char*)line);
	  fprintf(stderr, " insert failed (ignored)\n");
	} else {
	  inserted++;
	}
	if(verbose) fprintf(stderr, "WordList::Read: inserting %s\n", (char*)word.Get());
      }

      line.trunc();
    }
  }
  return inserted;
}