#!/usr/bin/perl

# ===========================================================================
#
#                            PUBLIC DOMAIN NOTICE
#            National Center for Biotechnology Information (NCBI)
#
#  This software/database is a "United States Government Work" under the
#  terms of the United States Copyright Act.  It was written as part of
#  the author's official duties as a United States Government employee and
#  thus cannot be copyrighted.  This software/database is freely available
#  to the public for use. The National Library of Medicine and the U.S.
#  Government do not place any restriction on its use or reproduction.
#  We would, however, appreciate having the NCBI and the author cited in
#  any work or product based on this material.
#
#  Although all reasonable efforts have been taken to ensure the accuracy
#  and reliability of the software and data, the NLM and the U.S.
#  Government do not and cannot warrant the performance or results that
#  may be obtained by using this software or data. The NLM and the U.S.
#  Government disclaim all warranties, express or implied, including
#  warranties of performance, merchantability or fitness for any particular
#  purpose.
#
# ===========================================================================
#
# File Name:  nquire
#
# Author:  Jonathan Kans
#
# Version Creation Date:   8/20/12
#
# ==========================================================================

# Entrez Direct - EDirect

# use strict;
use warnings;

use LWP::Simple;
use LWP::UserAgent;
use POSIX;
use URI::Escape;

# definitions

use constant false => 0;
use constant true  => 1;

# nquire version number

$version = "2.00";

# utility subroutines

sub clearflags {
  %macros = ();
  $alias = "";
  $debug = false;
  $http = "";
  $output = "";
}

sub map_macros {

  $qury = shift (@_);

  if ( $qury !~ /\(#/ ) {
    return $qury;
  }

  if ( scalar (keys %macros) > 0 ) {
    for ( keys %macros ) {
      $ky = $_;
      $vl = $macros{$_};
      $qury =~ s/\((\#$ky)\)/$vl/g;
    }
  }

  return $qury;
}

sub read_aliases {

  if ( $alias ne "" ) {
    if (open (my $PROXY_IN, $alias)) {
      while ( $thisline = <$PROXY_IN> ) {
        $thisline =~ s/\r//;
        $thisline =~ s/\n//;
        $thisline =~ s/ +/ /g;
        $thisline =~ s/> </></g;

        if ( $thisline =~ /(.+)\t(.+)/ ) {
          $ky = $1;
          $vl = $2;
          $vl =~ s/\"//g;
          $macros{"$ky"} = "$vl";
        }
      }
      close ($PROXY_IN);
    } else {
      print STDERR "Unable to open alias file '$alias'\n";
    }
  }
}

# send actual query

sub do_post {

  $urlx = shift (@_);
  $argx = shift (@_);

  $rslt = "";

  if ( $debug ) {
    print STDERR "$urlx?$argx\n";
  }

  if ( $http eq "get" or $http eq "GET" ) {
    if ( $argx ne "" ) {
      $urlx .= "?";
      $urlx .= "$argx";
    }

    $rslt = get ($urlx);

    if ( $rslt eq "" ) {
      print STDERR "No do_get output returned from '$urlx'\n";
    }

    if ( $debug ) {
      print STDERR "$rslt\n";
    }

    return $rslt;
  }

  $usragnt = new LWP::UserAgent (timeout => 300);

  $req = new HTTP::Request POST => "$urlx";
  $req->content_type('application/x-www-form-urlencoded');
  $req->content("$argx");

  $res = $usragnt->request ( $req );

  if ( $res->is_success) {
    $rslt = $res->content;
  }

  if ( $rslt eq "" ) {
    if ( $argx ne "" ) {
      $urlx .= "?";
      $urlx .= "$argx";
    }
    print STDERR "No do_post output returned from '$urlx'\n";
  }

  if ( $debug ) {
    print STDERR "$rslt\n";
  }

  return $rslt;
}

# uri_escape with backslash exceptions

sub do_uri_escape {

  $patx = shift (@_);

  $rslt = "";

  while ( $patx ne "" ) {
    if ( $patx =~ /^\\\\(.+)/ ) {
      $rslt .= "\\";
      $patx = $1;
    } elsif ( $patx =~ /^\\(.)(.+)/ ) {
      $rslt .= $1;
      $patx = $2;
    } elsif ( $patx =~ /^(.)(.+)/ ) {
      $rslt .= uri_escape ($1);
      $patx = $2;
    } elsif ( $patx =~ /^(.)/ ) {
      $rslt .= uri_escape ($1);
      $patx = "";
    }
  }

  return $rslt;
}

# nquire executes an external URL query from command line arguments

my $nquire_help = qq{
-url     Base URL for external search
-http    "get" uses HTTP GET instead of POST

};

sub nquire {

  # nquire -url http://... -tag value -tag value | ...

  $url = "";
  $arg = "";
  $pfx = "";
  $amp = "";
  $pat = "";

  @args = @ARGV;
  $max = scalar @args;

  if ( $max > 0 and $ARGV[0] eq "-help" ) {
    print "nquire $version\n";
    print $nquire_help;
    return;
  }

  if ( $max > 0 and $ARGV[0] eq "-version" ) {
    print "$version\n";
    return;
  }

  if ( $max < 2 ) {
    return;
  }

  $i = 0;

  # if present, -debug must be first argument

  if ( $i < $max ) {
    $pat = $args[$i];
    if ( $pat eq "-debug" ) {
      $i++;
      $debug = true;
    }
  }

  # if present, -http get must be first argument

  if ( $i < $max ) {
    $pat = $args[$i];
    if ( $pat eq "-http" ) {
      $i++;
      if ( $i < $max ) {
        $http = $args[$i];
        $i++;
      }
    }
  }

  # read file of keyword shortcuts for URL expansion

  if ( $i < $max ) {
    $pat = $args[$i];
    if ( $pat eq "-alias" ) {
      $i++;
      if ( $i < $max ) {
        $alias = $args[$i];
        if ( $alias ne "" ) {
          read_aliases ();
        }
        $i++;
      }
    }
  }

  # read URL

  if ( $i < $max ) {
    $pat = $args[$i];
    if ( $pat eq "-url" ) {
      $i++;
      if ( $i < $max ) {
        $url = $args[$i];
        $url = map_macros ($url);
        $i++;
      }
    }
  }

  if ( $url eq "" ) {
    return;
  }

  # hard-coded URL aliases for common NCBI web sites

  if ( $url =~ /\(#/ ) {
    $ky = "ncbi_url";
    $vl = "http://www.ncbi.nlm.nih.gov";
    $url =~ s/\((\#$ky)\)/$vl/g;

    $ky = "eutils_url";
    $vl = "http://eutils.ncbi.nlm.nih.gov/entrez/eutils";
    $url =~ s/\((\#$ky)\)/$vl/g;
  }

  # arguments before next minus are added to base URL as /value

  $go_on = true;
  while ( $i < $max and $go_on ) {
    $pat = $args[$i];
    if ( $pat =~ /^-(.+)/ ) {
      $go_on = false;
    } else {
      $pat = map_macros ($pat);
      $url .= "/" . $pat;
      $i++;
    }
  }

  # now expect tag with minus and value[s] without, add as &tag=value[,value]

  while ( $i < $max ) {
    $pat = $args[$i];
    if ( $pat =~ /^-(.+)/ ) {
      $pat = $1;
      $pfx = $amp . "$pat=";
      $amp = "";
    } else {
      $pat =~ s/^\\-/-/g;
      $pat = map_macros ($pat);
      $enc = do_uri_escape($pat);
      $arg .= $pfx . $enc;
      $pfx = ",";
      $amp = "&";
    }
    $i++;
  }

  if ( $debug ) {
    if ( $arg eq "" ) {
      print "$url\n";
    } else {
      print "$url?$arg\n";
    }
    return;
  }

  $output = do_post ($url, $arg);

  print "$output";
}

# initialize

clearflags ();

# execute URL request

nquire ();

# close input and output files

close (STDIN);
close (STDOUT);
close (STDERR);