package SQL::Translator::Utils;

use strict;
use warnings;
use Digest::SHA qw( sha1_hex );
use File::Spec;
use Scalar::Util qw(blessed);
use Try::Tiny;
use Carp qw(carp croak);

our $VERSION = '1.59';
our $DEFAULT_COMMENT = '-- ';

use base qw(Exporter);
our @EXPORT_OK = qw(
    debug normalize_name header_comment parse_list_arg truncate_id_uniquely
    $DEFAULT_COMMENT parse_mysql_version parse_dbms_version
    ddl_parser_instance batch_alter_table_statements
    throw ex2err carp_ro
    normalize_quote_options
);
use constant COLLISION_TAG_LENGTH => 8;

sub debug {
    my ($pkg, $file, $line, $sub) = caller(0);
    {
        no strict qw(refs);
        return unless ${"$pkg\::DEBUG"};
    }

    $sub =~ s/^$pkg\:://;

    while (@_) {
        my $x = shift;
        chomp $x;
        $x =~ s/\bPKG\b/$pkg/g;
        $x =~ s/\bLINE\b/$line/g;
        $x =~ s/\bSUB\b/$sub/g;
        #warn '[' . $x . "]\n";
        print STDERR '[' . $x . "]\n";
    }
}

sub normalize_name {
    my $name = shift or return '';

    # The name can only begin with a-zA-Z_; if there's anything
    # else, prefix with _
    $name =~ s/^([^a-zA-Z_])/_$1/;

    # anything other than a-zA-Z0-9_ in the non-first position
    # needs to be turned into _
    $name =~ tr/[a-zA-Z0-9_]/_/c;

    # All duplicated _ need to be squashed into one.
    $name =~ tr/_/_/s;

    # Trim a trailing _
    $name =~ s/_$//;

    return $name;
}

sub normalize_quote_options {
    my $config = shift;

    my $quote;
    if (defined $config->{quote_identifiers}) {
      $quote = $config->{quote_identifiers};

      for (qw/quote_table_names quote_field_names/) {
        carp "Ignoring deprecated parameter '$_', since 'quote_identifiers' is supplied"
          if defined $config->{$_}
      }
    }
    # Legacy one set the other is not
    elsif (
      defined $config->{'quote_table_names'}
        xor
      defined $config->{'quote_field_names'}
    ) {
      if (defined $config->{'quote_table_names'}) {
        carp "Explicitly disabling the deprecated 'quote_table_names' implies disabling 'quote_identifiers' which in turn implies disabling 'quote_field_names'"
          unless $config->{'quote_table_names'};
        $quote = $config->{'quote_table_names'} ? 1 : 0;
      }
      else {
        carp "Explicitly disabling the deprecated 'quote_field_names' implies disabling 'quote_identifiers' which in turn implies disabling 'quote_table_names'"
          unless $config->{'quote_field_names'};
        $quote = $config->{'quote_field_names'} ? 1 : 0;
      }
    }
    # Legacy both are set
    elsif(defined $config->{'quote_table_names'}) {
      croak 'Setting quote_table_names and quote_field_names to conflicting values is no longer supported'
        if ($config->{'quote_table_names'} xor $config->{'quote_field_names'});

      $quote = $config->{'quote_table_names'} ? 1 : 0;
    }

    return $quote;
}

sub header_comment {
    my $producer = shift || caller;
    my $comment_char = shift;
    my $now = scalar localtime;

    $comment_char = $DEFAULT_COMMENT
        unless defined $comment_char;

    my $header_comment =<<"HEADER_COMMENT";
${comment_char}
${comment_char}Created by $producer
${comment_char}Created on $now
${comment_char}
HEADER_COMMENT

    # Any additional stuff passed in
    for my $additional_comment (@_) {
        $header_comment .= "${comment_char}${additional_comment}\n";
    }

    return $header_comment;
}

sub parse_list_arg {
    my $list = UNIVERSAL::isa( $_[0], 'ARRAY' ) ? shift : [ @_ ];

    #
    # This protects stringification of references.
    #
    if ( @$list && ref $list->[0] ) {
        return $list;
    }
    #
    # This processes string-like arguments.
    #
    else {
        return [
            map { s/^\s+|\s+$//g; $_ }
            map { split /,/ }
            grep { defined && length } @$list
        ];
    }
}

sub truncate_id_uniquely {
    my ( $desired_name, $max_symbol_length ) = @_;

    return $desired_name
      unless defined $desired_name && length $desired_name > $max_symbol_length;

    my $truncated_name = substr $desired_name, 0,
      $max_symbol_length - COLLISION_TAG_LENGTH - 1;

    # Hex isn't the most space-efficient, but it skirts around allowed
    # charset issues
    my $digest = sha1_hex($desired_name);
    my $collision_tag = substr $digest, 0, COLLISION_TAG_LENGTH;

    return $truncated_name
         . '_'
         . $collision_tag;
}


sub parse_mysql_version {
    my ($v, $target) = @_;

    return undef unless $v;

    $target ||= 'perl';

    my @vers;

    # X.Y.Z style
    if ( $v =~ / ^ (\d+) \. (\d{1,3}) (?: \. (\d{1,3}) )? $ /x ) {
        push @vers, $1, $2, $3;
    }

    # XYYZZ (mysql) style
    elsif ( $v =~ / ^ (\d) (\d{2}) (\d{2}) $ /x ) {
        push @vers, $1, $2, $3;
    }

    # XX.YYYZZZ (perl) style or simply X
    elsif ( $v =~ / ^ (\d+) (?: \. (\d{3}) (\d{3}) )? $ /x ) {
        push @vers, $1, $2, $3;
    }
    else {
        #how do I croak sanely here?
        die "Unparseable MySQL version '$v'";
    }

    if ($target eq 'perl') {
        return sprintf ('%d.%03d%03d', map { $_ || 0 } (@vers) );
    }
    elsif ($target eq 'mysql') {
        return sprintf ('%d%02d%02d', map { $_ || 0 } (@vers) );
    }
    else {
        #how do I croak sanely here?
        die "Unknown version target '$target'";
    }
}

sub parse_dbms_version {
    my ($v, $target) = @_;

    return undef unless $v;

    my @vers;

    # X.Y.Z style
    if ( $v =~ / ^ (\d+) \. (\d{1,3}) (?: \. (\d{1,3}) )? $ /x ) {
        push @vers, $1, $2, $3;
    }

    # XX.YYYZZZ (perl) style or simply X
    elsif ( $v =~ / ^ (\d+) (?: \. (\d{3}) (\d{3}) )? $ /x ) {
        push @vers, $1, $2, $3;
    }
    else {
        #how do I croak sanely here?
        die "Unparseable database server version '$v'";
    }

    if ($target eq 'perl') {
        return sprintf ('%d.%03d%03d', map { $_ || 0 } (@vers) );
    }
    elsif ($target eq 'native') {
        return join '.' => grep defined, @vers;
    }
    else {
        #how do I croak sanely here?
        die "Unknown version target '$target'";
    }
}

#my ($parsers_libdir, $checkout_dir);
sub ddl_parser_instance {

    my $type = shift;

    # it may differ from our caller, even though currently this is not the case
    eval "require SQL::Translator::Parser::$type"
        or die "Unable to load grammar-spec container SQL::Translator::Parser::$type:\n$@";

    # handle DB2 in a special way, since the grammar source was lost :(
    if ($type eq 'DB2') {
      require SQL::Translator::Parser::DB2::Grammar;
      return SQL::Translator::Parser::DB2::Grammar->new;
    }

    require Parse::RecDescent;
    return Parse::RecDescent->new(do {
      no strict 'refs';
      ${"SQL::Translator::Parser::${type}::GRAMMAR"}
        || die "No \$SQL::Translator::Parser::${type}::GRAMMAR defined, unable to instantiate PRD parser\n"
    });

# this is disabled until RT#74593 is resolved

=begin sadness

    unless ($parsers_libdir) {

        # are we in a checkout?
        if ($checkout_dir = _find_co_root()) {
            $parsers_libdir = File::Spec->catdir($checkout_dir, 'share', 'PrecompiledParsers');
        }
        else {
            require File::ShareDir;
            $parsers_libdir = File::Spec->catdir(
              File::ShareDir::dist_dir('SQL-Translator'),
              'PrecompiledParsers'
            );
        }

        unshift @INC, $parsers_libdir;
    }

    my $precompiled_mod = "Parse::RecDescent::DDL::SQLT::$type";

    # FIXME FIXME FIXME
    # Parse::RecDescent has horrible architecture where each precompiled parser
    # instance shares global state with all its siblings
    # What we do here is gross, but scarily efficient - the parser compilation
    # is much much slower than an unload/reload cycle
    require Class::Unload;
    Class::Unload->unload($precompiled_mod);

    # There is also a sub-namespace that P::RD uses, but simply unsetting
    # $^W to stop redefine warnings seems to be enough
    #Class::Unload->unload("Parse::RecDescent::$precompiled_mod");

    eval "local \$^W; require $precompiled_mod" or do {
        if ($checkout_dir) {
            die "Unable to find precompiled grammar for $type - run Makefile.PL to generate it\n";
        }
        else {
            die "Unable to load precompiled grammar for $type... this is not supposed to happen if you are not in a checkout, please file a bugreport:\n$@"
        }
    };

    my $grammar_spec_fn = $INC{"SQL/Translator/Parser/$type.pm"};
    my $precompiled_fn = $INC{"Parse/RecDescent/DDL/SQLT/$type.pm"};

    if (
        (stat($grammar_spec_fn))[9]
            >
        (stat($precompiled_fn))[9]
    ) {
        die (
            "Grammar spec '$grammar_spec_fn' is newer than precompiled parser '$precompiled_fn'"
          . ($checkout_dir
                ? " - run Makefile.PL to regenerate stale versions\n"
                : "... this is not supposed to happen if you are not in a checkout, please file a bugreport\n"
            )
        );
    }

    return $precompiled_mod->new;

=end sadness

=cut

}

# Try to determine the root of a checkout/untar if possible
# or return undef
sub _find_co_root {

    my @mod_parts = split /::/, (__PACKAGE__ . '.pm');
    my $rel_path = join ('/', @mod_parts);  # %INC stores paths with / regardless of OS

    return undef unless ($INC{$rel_path});

    # a bit convoluted, but what we do here essentially is:
    #  - get the file name of this particular module
    #  - do 'cd ..' as many times as necessary to get to lib/SQL/Translator/../../..

    my $root = (File::Spec::Unix->splitpath($INC{$rel_path}))[1];
    for (1 .. @mod_parts) {
        $root = File::Spec->catdir($root, File::Spec->updir);
    }

    return ( -f File::Spec->catfile($root, 'Makefile.PL') )
        ? $root
        : undef
    ;
}

{
    package SQL::Translator::Utils::Error;

    use overload
        '""' => sub { ${$_[0]} },
        fallback => 1;

    sub new {
        my ($class, $msg) = @_;
        bless \$msg, $class;
    }
}

sub throw {
    die SQL::Translator::Utils::Error->new($_[0]);
}

sub ex2err {
    my ($orig, $self, @args) = @_;
    return try {
        $self->$orig(@args);
    } catch {
        die $_ unless blessed($_) && $_->isa("SQL::Translator::Utils::Error");
        $self->error("$_");
    };
}

sub carp_ro {
    my ($name) = @_;
    return sub {
        my ($orig, $self) = (shift, shift);
        carp "'$name' is a read-only accessor" if @_;
        return $self->$orig;
    };
}

sub batch_alter_table_statements {
    my ($diff_hash, $options, @meths) = @_;

    @meths = qw(
        rename_table
        alter_drop_constraint
        alter_drop_index
        drop_field
        add_field
        alter_field
        rename_field
        alter_create_index
        alter_create_constraint
        alter_table
    ) unless @meths;

    my $package = caller;

    return map {
        my $meth = $package->can($_) or die "$package cant $_";
        map { $meth->(ref $_ eq 'ARRAY' ? @$_ : $_, $options) } @{ $diff_hash->{$_} }
    } grep { @{$diff_hash->{$_} || []} }
        @meths;
}

1;

=pod

=head1 NAME

SQL::Translator::Utils - SQL::Translator Utility functions

=head1 SYNOPSIS

  use SQL::Translator::Utils qw(debug);
  debug("PKG: Bad things happened");

=head1 DESCSIPTION

C<SQL::Translator::Utils> contains utility functions designed to be
used from the other modules within the C<SQL::Translator> modules.

Nothing is exported by default.

=head1 EXPORTED FUNCTIONS AND CONSTANTS

=head2 debug

C<debug> takes 0 or more messages, which will be sent to STDERR using
C<warn>.  Occurances of the strings I<PKG>, I<SUB>, and I<LINE>
will be replaced by the calling package, subroutine, and line number,
respectively, as reported by C<caller(1)>.

For example, from within C<foo> in F<SQL/Translator.pm>, at line 666:

  debug("PKG: Error reading file at SUB/LINE");

Will warn

  [SQL::Translator: Error reading file at foo/666]

The entire message is enclosed within C<[> and C<]> for visual clarity
when STDERR is intermixed with STDOUT.

=head2 normalize_name

C<normalize_name> takes a string and ensures that it is suitable for
use as an identifier.  This means: ensure that it starts with a letter
or underscore, and that the rest of the string consists of only
letters, numbers, and underscores.  A string that begins with
something other than [a-zA-Z] will be prefixer with an underscore, and
all other characters in the string will be replaced with underscores.
Finally, a trailing underscore will be removed, because that's ugly.

  normalize_name("Hello, world");

Produces:

  Hello_world

A more useful example, from the C<SQL::Translator::Parser::Excel> test
suite:

  normalize_name("silly field (with random characters)");

returns:

  silly_field_with_random_characters

=head2 header_comment

Create the header comment.  Takes 1 mandatory argument (the producer
classname), an optional comment character (defaults to $DEFAULT_COMMENT),
and 0 or more additional comments, which will be appended to the header,
prefixed with the comment character.  If additional comments are provided,
then a comment string must be provided ($DEFAULT_COMMENT is exported for
this use).  For example, this:

  package My::Producer;

  use SQL::Translator::Utils qw(header_comment $DEFAULT_COMMENT);

  print header_comment(__PACKAGE__,
                       $DEFAULT_COMMENT,
                       "Hi mom!");

produces:

  --
  -- Created by My::Prodcuer
  -- Created on Fri Apr 25 06:56:02 2003
  --
  -- Hi mom!
  --

Note the gratuitous spacing.

=head2 parse_list_arg

Takes a string, list or arrayref (all of which could contain
comma-separated values) and returns an array reference of the values.
All of the following will return equivalent values:

  parse_list_arg('id');
  parse_list_arg('id', 'name');
  parse_list_arg( 'id, name' );
  parse_list_arg( [ 'id', 'name' ] );
  parse_list_arg( qw[ id name ] );

=head2 truncate_id_uniquely

Takes a string ($desired_name) and int ($max_symbol_length). Truncates
$desired_name to $max_symbol_length by including part of the hash of
the full name at the end of the truncated name, giving a high
probability that the symbol will be unique. For example,

  truncate_id_uniquely( 'a' x 100, 64 )
  truncate_id_uniquely( 'a' x 99 . 'b', 64 );
  truncate_id_uniquely( 'a' x 99,  64 )

Will give three different results; specifically:

  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa_7f900025
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa_6191e39a
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa_8cd96af2

=head2 $DEFAULT_COMMENT

This is the default comment string, '-- ' by default.  Useful for
C<header_comment>.

=head2 parse_mysql_version

Used by both L<Parser::MySQL|SQL::Translator::Parser::MySQL> and
L<Producer::MySQL|SQL::Translator::Producer::MySQL> in order to provide a
consistent format for both C<< parser_args->{mysql_parser_version} >> and
C<< producer_args->{mysql_version} >> respectively. Takes any of the following
version specifications:

  5.0.3
  4.1
  3.23.2
  5
  5.001005  (perl style)
  30201     (mysql style)

=head2 parse_dbms_version

Takes a version string (X.Y.Z) or perl style (XX.YYYZZZ) and a target ('perl'
or 'native') transforms the string to the given target style.
to

=head2 throw

Throws the provided string as an object that will stringify back to the
original string.  This stops it from being mangled by L<Moo>'s C<isa>
code.

=head2 ex2err

Wraps an attribute accessor to catch any exception raised using
L</throw> and store them in C<< $self->error() >>, finally returning
undef.  A reference to this function can be passed directly to
L<Moo/around>.

    around foo => \&ex2err;

    around bar => sub {
        my ($orig, $self) = (shift, shift);
        return ex2err($orig, $self, @_) if @_;
        ...
    };

=head2 carp_ro

Takes a field name and returns a reference to a function can be used
L<around|Moo/around> a read-only accessor to make it L<carp|Carp>
instead of die when passed an argument.

=head2 batch_alter_table_statements

Takes diff and argument hashes as passed to
L<batch_alter_table|SQL::Translator::Diff/batch_alter_table($table, $hash, $args) (optional)>
and an optional list of producer functions to call on the calling package.
Returns the list of statements returned by the producer functions.

If no producer functions are specified, the following functions in the
calling package are called:

=over

=item 1. rename_table

=item 2. alter_drop_constraint

=item 3. alter_drop_index

=item 4. drop_field

=item 5. add_field

=item 5. alter_field

=item 6. rename_field

=item 7. alter_create_index

=item 8. alter_create_constraint

=item 9. alter_table

=back

If the corresponding array in the hash has any elements, but the
caller doesn't implement that function, an exception is thrown.

=head1 AUTHORS

Darren Chamberlain E<lt>darren@cpan.orgE<gt>,
Ken Y. Clark E<lt>kclark@cpan.orgE<gt>.

=cut
