use warnings;
use strict;
use utf8;
use FileHandle;
use Data::Dumper;

my $document = &parseXML("mut.xml");

my $log = new FileHandle "dump.txt", "w+";

print $log Dumper($document);

sub parseXML {
    #args
    my $file = shift;

    #pre-declared vars
    my %doc;
    my $preSymbol;
    my $currSymbol;
    my $currElement;
    my $depth = 0;

    my $fh = new FileHandle $file, "r";
    my $log = new FileHandle "log.txt", "w+";

    CHAR: while($currSymbol = getc($fh)) {
	print $log "entering while. current: $currSymbol\n";

	if($currSymbol eq "<") {
	    my $nextSymbol = getc($fh);

	    print $log "current: $currSymbol next: $nextSymbol\n";
	    
	    my %element;
	    my $elementName = "";
	    my $attributes = "";

	    #if this is a letter then this is a start tag
	    #then read until you reach a space.
	    #attribs should be following or the end of the tag
	    if($nextSymbol =~ m/\p{IsAlpha}/) {
		$preSymbol = $currSymbol;
		$currSymbol = $nextSymbol;
		$depth++;

		print $log "next symbol is a word char. current: $currSymbol\n";

		until($currSymbol eq " " or $currSymbol eq ">") {
		    print $log "Getting element name\n";
		    $elementName .= $currSymbol;
		    $preSymbol = $currSymbol;
		    $currSymbol = getc($fh);
		}
		
		print $log "Element name: $elementName\n";

		if($currSymbol eq " ") {
		    until($currSymbol eq ">") {
			print $log "getting attributes\n";
			$attributes .= $currSymbol;
			$preSymbol = $currSymbol;
			$currSymbol = getc($fh);
		    }
		}
		
		print $log "Attribs are: $attributes\n";

		if($currSymbol eq ">") {
		    print $log "done getting element info. Depth: $depth\n";
		    $element{name} = $elementName;
		    $element{attributes} = $attributes;
		    $element{children} = [];
		    $element{depth} = $depth;

		    if($depth == 1) {
			$doc{root} = \%element;
			$currElement = $doc{root};
		    }else{
			#this is checking to see if this element is
			#an empty element.  The : are the boundries
			#for the regular expressions.
			if($element{name} =~ m:/:) {
			    print $log "this is an empty element.\n";
			    $element{name} =~ s:/::;
			    $depth--;
			    
			    my $children = $currElement->{children};
			    push @{$children}, \%element;

			    print $log "adding to parent node and going to next char.\n";
			    next CHAR;
			}else {
			    my $children = $currElement->{children};
			    push @{$children}, \%element;

			    $currElement = \%element;
			    print $log "going to next char in the while loop.\n";
			    next CHAR;
			}
		    }
		}else {
		    print $log "Symbol: $currSymbol is not recognized\n";
		}
	    }
	    #need to determine if this is an end element or
	    #an empty element
	    #if this is a / then this is an end tag
	    #then read until the end >		
	    elsif($nextSymbol eq "/") {
		print $log "next symbol is a / ending element.\n";
		$currElement->{status} = "closed";
		$depth--;

		$preSymbol = $currSymbol;
		$currSymbol = $nextSymbol;

		until($currSymbol eq ">") {
		    $preSymbol = $currSymbol;
		    $currSymbol = getc($fh);
		}

		#went forward one too may symbols
		seek($fh, -1, 1);
		print $log "element finished\n";
	    }
	    #if this is a ? then this is a processing instuction
	    #read until the space for the application name
	    #then compare that to make sure that it is not the xml decl
	    #that happens at the beginning of a document
	    #then read until the next ?
	    elsif($nextSymbol eq "?") {
		print $log "Found processing instuction.\n";
		
		my $appName = "";
		my $appInfo = "";

		$preSymbol = $currSymbol;
		$currSymbol = getc($fh);

		print $log "Reading app name for PI.\n";
		until($currSymbol eq " ") {
		    $appName .= $currSymbol;
		    $preSymbol = $currSymbol;
		    $currSymbol = getc($fh);
		}
		print $log "appname is $appName.\n";
		if($appName eq "xml") {
		    print $log "This is the standard decl for xml.\n";
		    until($currSymbol eq "?") {
			$appInfo .= $currSymbol;
			$preSymbol = $currSymbol;
			$currSymbol = getc($fh);
		    }

		    $doc{xmldecl} = $appInfo;
		    next CHAR;
		}else {
		    print $log "This is a true PI.\n";
		    until($currSymbol eq "?") {
			$appInfo .= $currSymbol;
			$preSymbol = $currSymbol;
			$currSymbol = getc($fh);
		    }
		    
		    $currElement->{PI}->{$appName} = $appInfo;
		}
	    }
	}elsif($currSymbol =~ m/\p{IsAlnum}|\p{IsSpace}/) {
	    my $content = "";
	    
	    print $log "adding content to current element.\n";
	    until($currSymbol eq "<") {
		$content .= $currSymbol;
		$preSymbol = $currSymbol;
		$currSymbol = getc($fh);
	    }

	    $currElement->{content} .= $content;

	    #went forward one too many symbols
	    seek($fh, -1, 1);
	    next CHAR;
	}
    }

    print $log "Current symbol: $currSymbol. Presymbol: $preSymbol\nfinished with document.\n";
    
    return \%doc;
}