/* This file is part of the KDE project
   Copyright (C) 1998-2002 The KSpread Team
                           www.koffice.org/kspread
   Copyright (C) 2005 Tomas Mecir <mecirt@gmail.com>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License.

   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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
*/

// built-in database functions

#include "functions.h"
#include "valuecalc.h"
#include "valueconverter.h"

using namespace KSpread;

// prototypes
Value func_daverage (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dcount (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dcounta (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dget (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dmax (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dmin (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dproduct (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dstdev (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dstdevp (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dsum (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dvar (valVector args, ValueCalc *calc, FuncExtra *);
Value func_dvarp (valVector args, ValueCalc *calc, FuncExtra *);
Value func_getpivotdata (valVector args, ValueCalc *calc, FuncExtra *);

// registers all database functions
void RegisterDatabaseFunctions()
{
  FunctionRepository* repo = FunctionRepository::self();
  Function *f;

  f = new Function ("DAVERAGE",     func_daverage);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DCOUNT",       func_dcount);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DCOUNTA",      func_dcounta);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DGET",         func_dget);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DMAX",         func_dmax);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DMIN",         func_dmin);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DPRODUCT",     func_dproduct);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DSTDEV",       func_dstdev);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DSTDEVP",      func_dstdevp);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DSUM",         func_dsum);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DVAR",         func_dvar);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("DVARP",        func_dvarp);
  f->setParamCount (3);
  f->setAcceptArray ();
  repo->add (f);
  f = new Function ("GETPIVOTDATA", func_getpivotdata); // partially Excel-compatible
  f->setParamCount (2);
  f->setAcceptArray ();
  repo->add (f);
}

int getFieldIndex (ValueCalc *calc, Value fieldName,
    Value database)
{
  if (fieldName.isNumber())
    return fieldName.asInteger() - 1;
  if (!fieldName.isString ())
    return -1;

  TQString fn = fieldName.asString();
  int cols = database.columns ();
  for (int i = 0; i < cols; ++i)
    if (fn.lower() ==
        calc->conv()->asString (database.element (i, 0)).asString().lower())
    return i;
  return -1;
}

// ***********************************************************
// *** DBConditions class - maintains an array of conditions ***
// ***********************************************************

class DBConditions {
 public:
  DBConditions (ValueCalc *vc, Value database, Value conds);
  ~DBConditions ();
  /** Does a specified row of the database match the given criteria?
  The row with column names is ignored - hence 0 specifies first data row. */
  bool matches (unsigned row);
 private:
  void parse (Value conds);
  ValueCalc *calc;
  Condition **cond;
  int rows, cols;
  Value db;
};

DBConditions::DBConditions (ValueCalc *vc, Value database,
    Value conds) : calc(vc), cond(0), rows(0), cols(0), db(database)
{
  parse (conds);
}

DBConditions::~DBConditions () {
  int count = rows*cols;
  for (int r = 0; r < count; ++r)
    delete cond[r];
  delete[] cond;
}

void DBConditions::parse (Value conds)
{
  // initialize the array
  rows = conds.rows() - 1;
  cols = db.columns();
  int count = rows*cols;
  cond = new Condition* [count];
  for (int r = 0; r < count; ++r)
    cond[r] = 0;

  // perform the parsing itself
  int cc = conds.columns ();
  for (int c = 0; c < cc; ++c)
  {
    // first row contains column names
    int col = getFieldIndex (calc, conds.element (c, 0), db);
    if (col < 0) continue;  // failed - ignore the column

    // fill in the conditions for a given column name
    for (int r = 0; r < rows; ++r) {
      Value cnd = conds.element (c, r+1);
      if (cnd.isEmpty()) continue;
      int idx = r * cols + col;
      if (cond[idx]) delete cond[idx];
      cond[idx] = new Condition;
      calc->getCond (*cond[idx], cnd);
    }
  }
}

bool DBConditions::matches (unsigned row)
{
  if (row >= db.rows() - 1)
    return false;    // out of range

  // we have a match, if at least one row of criteria matches
  for (int r = 0; r < rows; ++r) {
    // within a row, all criteria must match
    bool match = true;
    for (int c = 0; c < cols; ++c) {
      int idx = r * cols + c;
      if (!cond[idx]) continue;
      if (!calc->matches (*cond[idx], db.element (c, row + 1))) {
        match = false;  // didn't match
        break;
      }
    }
    if (match)  // all conditions in this row matched
      return true;
  }

  // no row matched
  return false;
}


// *******************************************
// *** Function implementations start here ***
// *******************************************

// Function: DSUM
Value func_dsum (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  Value conditions = args[2];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();

  DBConditions conds (calc, database, conditions);

  int rows = database.rows() - 1;  // first row contains column names
  Value res( Value::Float );
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if (!val.isEmpty ())
        res = calc->add (res, val);
    }

  return res;
}

// Function: DAVERAGE
Value func_daverage (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  Value conditions = args[2];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();

  DBConditions conds (calc, database, conditions);

  int rows = database.rows() - 1;  // first row contains column names
  Value res;
  int count = 0;
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if (!val.isEmpty ()) {
        res = calc->add (res, val);
        count++;
      }
    }
  if (count) res = calc->div (res, count);
  return res;
}

// Function: DCOUNT
Value func_dcount (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  Value conditions = args[2];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();

  DBConditions conds (calc, database, conditions);

  int rows = database.rows() - 1;  // first row contains column names
  int count = 0;
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if ((!val.isEmpty()) && (!val.isBoolean()) && (!val.isString()))
        count++;
    }

  return Value (count);
}

// Function: DCOUNTA
Value func_dcounta (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  Value conditions = args[2];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();

  DBConditions conds (calc, database, conditions);

  int rows = database.rows() - 1;  // first row contains column names
  int count = 0;
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if (!val.isEmpty())
        count++;
    }

  return Value (count);
}

// Function: DGET
Value func_dget (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  Value conditions = args[2];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();

  DBConditions conds (calc, database, conditions);

  bool match = false;
  Value result = Value::errorVALUE();
  int rows = database.rows() - 1;  // first row contains column names
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      if (match) {
        // error on multiple matches
        result = Value::errorVALUE();
        break;
      }
      result = database.element (fieldIndex, r + 1);
      match = true;
    }

  return result;
}

// Function: DMAX
Value func_dmax (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  Value conditions = args[2];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();

  DBConditions conds (calc, database, conditions);

  int rows = database.rows() - 1;  // first row contains column names
  Value res;
  bool got = false;
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if (!val.isEmpty ()) {
        if (!got) {
          res = val;
          got = true;
        }
        else
          if (calc->greater (val, res))
            res = val;
      }
    }

  return res;
}

// Function: DMIN
Value func_dmin (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  Value conditions = args[2];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();

  DBConditions conds (calc, database, conditions);

  int rows = database.rows() - 1;  // first row contains column names
  Value res;
  bool got = false;
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if (!val.isEmpty ()) {
        if (!got) {
          res = val;
          got = true;
        }
        else
          if (calc->lower (val, res))
            res = val;
      }
    }

  return res;
}

// Function: DPRODUCT
Value func_dproduct (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  Value conditions = args[2];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();

  DBConditions conds (calc, database, conditions);

  int rows = database.rows() - 1;  // first row contains column names
  Value res = 1.0;
  bool got = false;
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if (!val.isEmpty ()) {
        got = true;
        res = calc->mul (res, val);
      }
    }
  if (got)
    return res;
  return Value::errorVALUE ();
}

// Function: DSTDEV
Value func_dstdev (valVector args, ValueCalc *calc, FuncExtra *)
{
  // sqrt (dvar)
  return calc->sqrt (func_dvar (args, calc, 0));
}

// Function: DSTDEVP
Value func_dstdevp (valVector args, ValueCalc *calc, FuncExtra *)
{
  // sqrt (dvarp)
  return calc->sqrt (func_dvarp (args, calc, 0));
}

// Function: DVAR
Value func_dvar (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  Value conditions = args[2];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();

  DBConditions conds (calc, database, conditions);

  int rows = database.rows() - 1;  // first row contains column names
  Value avg;
  int count = 0;
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if (!val.isEmpty ()) {
        avg = calc->add (avg, val);
        count++;
      }
    }
  if (count < 2) return Value::errorDIV0();
  avg = calc->div (avg, count);

  Value res;
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if (!val.isEmpty ())
        res = calc->add (res, calc->sqr (calc->sub (val, avg)));
    }

  // res / (count-1)
  return calc->div (res, count - 1);
}

// Function: DVARP
Value func_dvarp (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  Value conditions = args[2];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();

  DBConditions conds (calc, database, conditions);

  int rows = database.rows() - 1;  // first row contains column names
  Value avg;
  int count = 0;
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if (!val.isEmpty ()) {
        avg = calc->add (avg, val);
        count++;
      }
    }
  if (count == 0) return Value::errorDIV0();
  avg = calc->div (avg, count);

  Value res;
  for (int r = 0; r < rows; ++r)
    if (conds.matches (r)) {
      Value val = database.element (fieldIndex, r + 1);
      // include this value in the result
      if (!val.isEmpty ())
        res = calc->add (res, calc->sqr (calc->sub (val, avg)));
    }

  // res / count
  return calc->div (res, count);
}

// Function: GETPIVOTDATA
// FIXME implement more things with this, see Excel !
Value func_getpivotdata (valVector args, ValueCalc *calc, FuncExtra *)
{
  Value database = args[0];
  int fieldIndex = getFieldIndex (calc, args[1], database);
  if (fieldIndex < 0)
    return Value::errorVALUE();
  // the row at the bottom
  int row = database.rows() - 1;

  return database.element (fieldIndex, row);
}