#!/usr/bin/perl -w

use strict;
use XML::Twig;

sub write_c_header(@);
sub write_c_impl_defaults(@);
sub write_c_impl_apply(@);
sub write_c_impl_free(@);
sub write_c_impl_dump(@);
sub get_data($);

# initialize parser and read the file
my $input = "./config.xml";
my $parser = XML::Twig->new();
my $tree = $parser->parsefile($input) || die "Unable to parse XML file.";

# Write header file
open GENHEAD, ">gen_config.h" || die "Unable to write header file";
print GENHEAD "/* THIS FILE IS AUTOGENERATED - DO NOT CHANGE IT! */\n\nstruct hub_config\n{\n";
foreach my $p ($tree->root->children("option"))
{
	my @data = ($p->att("type"), $p->att("name"), $p->att("default"), $p->att("advanced"), $p->children_text("short"), $p->children_text("description"), $p->children_text("since"), $p->children_text("example"));
	write_c_header(@data);
}
print GENHEAD "};\n\n";

# Write c source file
open GENIMPL, ">gen_config.c" || die "Unable to write source file";
print GENIMPL "/* THIS FILE IS AUTOGENERATED - DO NOT CHANGE IT! */\n\n";

# The defaults function
print GENIMPL "void config_defaults(struct hub_config* config)\n{\n";
foreach my $p ($tree->root->children("option"))
{
	write_c_impl_defaults(get_data($p));
}
print GENIMPL "}\n\n";

# apply function
print GENIMPL "static int apply_config(struct hub_config* config, char* key, char* data, int line_count)\n{\n";
foreach my $p ($tree->root->children("option"))
{
	write_c_impl_apply(get_data($p));
}
print GENIMPL "\t/* Still here -- unknown directive */\n";
print GENIMPL "\tLOG_ERROR(\"Unknown configuration directive: '%s'\", key);\n";
print GENIMPL "\t\treturn -1;\n";
print GENIMPL "}\n\n";

# free function (for strings)
print GENIMPL "void free_config(struct hub_config* config)\n{\n";
foreach my $p ($tree->root->children("option"))
{
	write_c_impl_free(get_data($p));
}
print GENIMPL "}\n\n";

# dump function
print GENIMPL "void dump_config(struct hub_config* config, int ignore_defaults)\n{\n";
foreach my $p ($tree->root->children("option"))
{
	write_c_impl_dump(get_data($p));
}
print GENIMPL "}\n\n";



sub write_c_header(@)
{
	my @output = @_;
	my ($type, $name, $default, $advanced, $short, $desc, $since, $example) = @output;

	print GENHEAD "\t";
	print GENHEAD "int  " if ($type eq "int");
	print GENHEAD "int  " if ($type eq "boolean");
	print GENHEAD "char*" if ($type =~ /(string|file|message)/);
	print GENHEAD " " . $name . ";";

	my $comment = "";
	if ($type eq "message")
	{
		$comment = "\"" . $default . "\"";
	}
	elsif (defined $short && length $short > 0)
	{
		$comment = $short;
		$comment .= " (default: " . $default . ")" if (defined $default);
	}

	if (length $comment > 0)
	{
		my $pad = "";
		for (my $i = length $name; $i < 32; $i++)
		{
			$pad .= " ";
		}
		$comment = $pad . "/*<<< " . $comment . " */";
	}

	print GENHEAD $comment . "\n";
}

sub write_c_impl_defaults(@)
{
	my @output = @_;
	my ($type, $name, $default, $advanced, $short, $desc, $since, $example) = @output;

	print GENIMPL "\t";
	print GENIMPL "DEFAULT_INTEGER" if ($type eq "int");
	print GENIMPL "DEFAULT_BOOLEAN" if ($type eq "boolean");

	if ($type =~ /(string|file|message)/)
	{
		print GENIMPL "DEFAULT_STRING ";
		$default = "\"" . $default . "\"";
	}
	print GENIMPL "(" . $name . ", " . $default . ");\n";
}

sub write_c_impl_apply(@)
{
	my @output = @_;
	my ($type, $name, $default, $advanced, $short, $desc, $since, $example) = @output;

	print GENIMPL "\t";
	print GENIMPL "GET_INT " if ($type eq "int");
	print GENIMPL "GET_BOOL" if ($type eq "boolean");
	print GENIMPL "GET_STR " if ($type =~ /(string|file|message)/);
	print GENIMPL "(" . $name . ");\n";
}

sub write_c_impl_free(@)
{
	my @output = @_;
	my ($type, $name, $default, $advanced, $short, $desc, $since, $example) = @output;

	print GENIMPL "\thub_free(config->" . $name . ");\n" if ($type =~ /(string|file|message)/)
}

sub write_c_impl_dump(@)
{
	my @output = @_;
	my ($type, $name, $default, $advanced, $short, $desc, $since, $example) = @output;

	print GENIMPL "\t";
	print GENIMPL "DUMP_INT " if ($type eq "int");
	print GENIMPL "DUMP_BOOL" if ($type eq "boolean");

	if ($type =~ /(string|file|message)/)
	{
		print GENIMPL "DUMP_STR";
		$default = "\"" . $default . "\"";
	}
	print GENIMPL "(" . $name . ", " . $default . ");\n"
}

sub get_data($)
{
	my $p = shift;
	my @data = ($p->att("type"), $p->att("name"), $p->att("default"), $p->att("advanced"), $p->children_text("short"), $p->children_text("description"), $p->children_text("since"), $p->children_text("example"));
	return @data;
}