// -----------------------------------------------------------------------
// Section.cc: Member functions for the Section class, particularly
//             how to interpret the subsection string.
// -----------------------------------------------------------------------
// Copyright (C) 2006, Matthew Whiting, ATNF
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2 of the License, or (at your
// option) any later version.
//
// Duchamp 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 General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License
// along with Duchamp; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
//
// Correspondence concerning Duchamp may be directed to:
//    Internet email: Matthew.Whiting [at] atnf.csiro.au
//    Postal address: Dr. Matthew Whiting
//                    Australia Telescope National Facility, CSIRO
//                    PO Box 76
//                    Epping NSW 1710
//                    AUSTRALIA
// -----------------------------------------------------------------------
#include <string>
#include <vector>
#include <iostream>
#include <sstream>
#include <duchamp/Utils/Section.hh>
#include <duchamp/duchamp.hh>

namespace duchamp
{

  Section::Section()
  {
    this->numSections = 0;
  }

  Section::Section(const Section& s)
  {
    operator=(s);
  }
  //--------------------------------------------
 
  Section& Section::operator= (const Section& s)
  {
    if(this == &s) return *this;
    this->subsection  = s.subsection;
    this->numSections = s.numSections;
    this->starts 	    = s.starts;
    this->dims        = s.dims;
    return *this;
  }
  //--------------------------------------------

  int Section::parse(std::vector<long> dimAxes)
  {
    /**
     * This function reads the subsection string, and registers the
     * starting values and lengths for each dimension. The array of axis
     * dimensions is needed to know how long each axis really is, and
     * whether we have strayed over the limit or not.
     *
     * Note that steps in the subsection string are not dealt with -- a
     * warning message is written to the screen, and the step values are
     * removed from the subsection string.
     *
     * The function also does basic checks to make sure it is of the
     * correct format (ie. has square brackets delimiting it) and the
     * correct number of sections, returning a FAILURE if either of
     * these checks fail.
     *
     * \param dimAxes The array of axis dimensions, of which the
     *                 Section is a subsection.
     * \return SUCCESS/FAILURE (from duchamp.hh)
     */

    std::stringstream errmsg;

    // First Make sure subsection has [ and ] at ends
    if((this->subsection[0]!='[') || 
       (this->subsection[this->subsection.size()-1]!=']')){
      errmsg.str("");
      errmsg << "Subsection needs to be delimited by square brackets\n"
	     << "You provided: " << this->subsection << std::endl;
      duchampError("Section parsing",errmsg.str());
      return FAILURE;
    }

    this->starts.clear();
    this->dims.clear();
  
    this->numSections=1;
    for(int i=0;i<this->subsection.size();i++)
      if(this->subsection[i]==',') this->numSections++;

    if(numSections!=dimAxes.size()){
      errmsg.str("");
      errmsg << "Subsection has "<<numSections
	     <<" sections, compared to a cube with "
	     << dimAxes.size() << " axes\n"
	     << "Subsection provided was: " << this->subsection << std::endl;
      duchampError("Section parsing",errmsg.str());
      return FAILURE;
    }

    this->starts.resize(this->numSections);
    this->dims.resize(this->numSections);

    std::vector<std::string> sections(numSections); 
    // this will hold the section strings for each dimension
    std::stringstream ss;
    ss.str(this->subsection);
    bool removeStep = false;
    bool doingBorders = false;
    std::string temp;

    getline(ss,temp,'[');
    for(int i=0;i<numSections-1;i++){
      getline(ss,temp,',');
      sections[i]=temp;
    }
    getline(ss,temp,']');
    sections[numSections-1]=temp;

    for(int str=0;str<numSections;str++){
      if(sections[str]=="*"){
	this->starts[str] = 0;
	this->dims[str]= dimAxes[str];
      }
      else{
	int numColon=0;
	for(int i=0;i<sections[str].size();i++){
	  if(sections[str][i]==':'){
	    sections[str][i]=' ';
	    numColon++;
	  }
	}
	int a,b,c;
	std::stringstream readString,fixedString;
	readString.str(sections[str]);
	switch(numColon){
	case 1: // usual case
	  readString >> a >> b;
	  this->starts[str] = a-1;
	  this->dims[str] = b-a+1;
	  break;
	case 0: // borders case -- so many off each border
	  readString >> a;
	  if(a>=dimAxes[str]/2){
	    errmsg.str("");
	    errmsg<< "You requested the subsection " << this->subsection
		  << " but axis #" << str+1 
		  <<" has zero size, since its dimension is " << dimAxes[str]
		  <<".\nI'm not going to parse this! Go and fix it.\n";
	    duchampError("Section parsing", errmsg.str());
	    return FAILURE;
	  }
	  this->starts[str] = a;
	  this->dims[str] = dimAxes[str]-2*a;
	  fixedString << this->starts[str]+1 << ":" 
		      << this->getEnd(str)+1;
	  sections[str] = fixedString.str();
	  doingBorders=true;
	  break;
	case 2: // subsection involves a step
	default:
	  readString>> a >> b >> c;
	  this->starts[str] = a-1;
	  this->dims[str] = b-a+1;
	  fixedString << a << ":" << b;
	  sections[str] = fixedString.str();
	  removeStep=true;
	  break;
	}

      }
    }

    if(removeStep){  // if there was a step present
      errmsg.str("");
      errmsg << "The subsection given is " << this->subsection <<".\n"
	     << "Duchamp is currently unable to deal with pixel steps"
	     << " in the subsection.\n"
	     << "These have been ignored, and so the subection used is ";
    }

    if(removeStep || doingBorders){
      // rewrite subsection without any step sizes and with correct borders.
      this->subsection = "[" + sections[0];
      for(int str=1;str<numSections;str++) 
	this->subsection += ',' + sections[str];
      this->subsection += "]";
    }

    if(removeStep){
      errmsg << this->subsection << std::endl;
      duchampWarning("Section parsing", errmsg.str());
    }

    return SUCCESS;
  
  }

}