package DBD::Parser;
require Exporter;

@ISA = qw(Exporter);
@EXPORT = qw(&ParseDBD);

use DBD;
use DBD::Base;
use DBD::Breaktable;
use DBD::Device;
use DBD::Driver;
use DBD::Menu;
use DBD::Recordtype;
use DBD::Recfield;
use DBD::Registrar;
use DBD::Function;
use DBD::Variable;

my $RXnam = qr/[a-zA-Z0-9_\-:.<>;]+/o;
my $RXnum = qr/-? (?: \d+ ) | (?: \d* \. \d+ ) (?: [eE] [-+]? \d+ )?/ox;
my $RXdqs = qr/" (?: [^"] | \\" )* "/ox;
my $RXsqs = qr/' (?: [^'] | \\' )* '/ox;
my $string = qr/ ( $RXnam | $RXnum | $RXdqs | $RXsqs ) /ox;

our $debug=0;

sub ParseDBD {
    my $dbd = shift;
    $_ = shift;
    while (1) {
        parseCommon();
        if (m/\G menu \s* \( \s* $string \s* \) \s* \{/oxgc) {
            print "Menu: $1\n" if $debug;
            parse_menu($dbd, $1);
        }
        elsif (m/\G driver \s* \( \s* $string \s* \)/oxgc) {
            print "Driver: $1\n" if $debug;
            $dbd->add(DBD::Driver->new($1));
        }
        elsif (m/\G registrar \s* \( \s* $string \s* \)/oxgc) {
            print "Registrar: $1\n" if $debug;
            $dbd->add(DBD::Registrar->new($1));
        }
        elsif (m/\G function \s* \( \s* $string \s* \)/oxgc) {
            print "Function: $1\n" if $debug;
            $dbd->add(DBD::Function($1));
        }
        elsif (m/\G breaktable \s* \( \s* $string \s* \) \s* \{/oxgc) {
            print "Breaktable: $1\n" if $debug;
            parse_breaktable($dbd, $1);
        }
        elsif (m/\G recordtype \s* \( \s* $string \s* \) \s* \{/oxgc) {
            print "Recordtype: $1\n" if $debug;
            parse_recordtype($dbd, $1);
        }
        elsif (m/\G variable \s* \( \s* $string \s* \)/oxgc) {
            print "Variable: $1\n" if $debug;
            $dbd->add(DBD::Variable->new($1, 'int'));
        }
        elsif (m/\G variable \s* \( \s* $string \s* , \s* $string \s* \)/oxgc) {
            print "Variable: $1, $2\n" if $debug;
            $dbd->add(DBD::Variable->new($1, $2));
        }
        elsif (m/\G device \s* \( \s* $string \s* , \s* $string \s* ,
                          \s* $string \s* , \s*$string \s* \)/oxgc) {
            print "Device: $1, $2, $3, $4\n" if $debug;
            my $rtyp = $dbd->recordtype($1);
            dieContext("Unknown record type '$1'") unless defined $rtyp;
            $rtyp->add_device(DBD::Device->new($2, $3, $4));
        } else {
            last unless m/\G (.*) $/moxgc;
            dieContext("Syntax error in '$1'");
        }
    }
}

sub parseCommon {
    while (1) {
        # Skip leading whitespace
        m/\G \s* /oxgc;

        if (m/\G \# /oxgc) {
            if (m/\G \#!BEGIN\{ ( [^}]* ) \}!\#\# \n/oxgc) {
                print "File-Begin: $1\n" if $debug;
                pushContext("file '$1'");
            }
            elsif (m/\G \#!END\{ ( [^}]* ) \}!\#\# \n?/oxgc) {
                print "File-End: $1\n" if $debug;
                popContext("file '$1'");
            }
            else {
                m/\G (.*) \n/oxgc;
                print "Comment: $1\n" if $debug;
            }
        } else {
            return;
        }
    }
}

sub parse_menu {
    my ($dbd, $name) = @_;
    pushContext("menu($name)");
    my $menu = DBD::Menu->new($name);
    while(1) {
        parseCommon();
        if (m/\G choice \s* \( \s* $string \s* , \s* $string \s* \)/oxgc) {
            print " Menu-Choice: $1, $2\n" if $debug;
            $menu->add_choice($1, $2);
        }
        elsif (m/\G \}/oxgc) {
            print " Menu-End:\n" if $debug;
            $dbd->add($menu);
            popContext("menu($name)");
            return;
        } else {
            m/\G (.*) $/moxgc or dieContext("Unexpected end of input");
            dieContext("Syntax error in '$1'");
        }
    }
}

sub parse_breaktable {
    my ($dbd, $name) = @_;
    pushContext("breaktable($name)");
    my $bt = DBD::Breaktable->new($name);
    while(1) {
        parseCommon();
        if (m/\G point\s* \(\s* $string \s* , \s* $string \s* \)/oxgc) {
            print " Breaktable-Point: $1, $2\n" if $debug;
            $bt->add_point($1, $2);
        }
        elsif (m/\G $string \s* (?: , \s*)? $string (?: \s* ,)?/oxgc) {
            print " Breaktable-Data: $1, $2\n" if $debug;
            $bt->add_point($1, $2);
        }
        elsif (m/\G \}/oxgc) {
            print " Breaktable-End:\n" if $debug;
            $dbd->add($bt);
            popContext("breaktable($name)");
            return;
        } else {
            m/\G (.*) $/moxgc or dieContext("Unexpected end of input");
            dieContext("Syntax error in '$1'");
        }
    }
}

sub parse_recordtype {
    my ($dbd, $name) = @_;
    pushContext("recordtype($name)");
    my $rtyp = DBD::Recordtype->new($name);
    while(1) {
        parseCommon();
        if (m/\G field \s* \( \s* $string \s* , \s* $string \s* \) \s* \{/oxgc) {
            print " Recordtype-Field: $1, $2\n" if $debug;
            parse_field($rtyp, $1, $2);
        }
        elsif (m/\G \}/oxgc) {
            print " Recordtype-End:\n" if $debug;
            $dbd->add($rtyp);
            popContext("recordtype($name)");
            return;
        }
        elsif (m/\G % (.*) \n/oxgc) {
            print " Recordtype-Cdef: $1\n" if $debug;
            $rtyp->add_cdef($1);
        } else {
            m/\G (.*) $/moxgc or dieContext("Unexpected end of input");
            dieContext("Syntax error in '$1'");
        }
    }
}

sub parse_field {
    my ($rtyp, $name, $field_type) = @_;
    my $fld = DBD::Recfield->new($name, $field_type);
    pushContext("field($name, $field_type)");
    while(1) {
        parseCommon();
        if (m/\G (\w+) \s* \( \s* $string \s* \)/oxgc) {
            print "  Field-Attribute: $1, $2\n" if $debug;
            $fld->add_attribute($1, $2);
        }
        elsif (m/\G \}/oxgc) {
            print "  Field-End:\n" if $debug;
            $rtyp->add_field($fld);
            popContext("field($name, $field_type)");
            return;
        } else {
            m/\G (.*) $/moxgc or dieContext("Unexpected end of input");
            dieContext("Syntax error in '$1'");
        }
    }
}

1;