#!/usr/bin/env perl
#
# Copyright (c) 2002,2014-2015,2020 Christian Jaeger, copying@christianjaeger.ch
#
# This is free software, offered under either the same terms as perl 5
# or the terms of the Artistic License version 2 or the terms of the
# MIT License (Expat version). See the file COPYING.md that came
# bundled with this file.
#
use strict;
use warnings;
use warnings FATAL => 'uninitialized';
use Cwd 'abs_path';
our ($mydir, $myname);
BEGIN {
    my $location = (-l $0) ? abs_path($0) : $0;
    $location =~ /(.*?)([^\/]+?)_?\z/s or die "?";
    ($mydir, $myname) = ($1, $2);
}
use lib "$mydir/../lib";
sub usage {
    print "$myname [ calculation(s) ]
  Repl-Enhanced PerL
  Evaluates the given string(s), or goes into interactive mode if
  none given.
  Interactive mode tricks:
  - uses readline (read up on its features)
  - entering nothing re-evaluates the last entry
  - 'strict vars' is not active, so there's no need to declare new
    globals with 'our'
  - global variables and subroutines stay around, lexical ('my')
    varibles don't
  - you can refer to '\$VAR1' etc. to get the correspondin result from the
    previous evaluation (as long as you're using the default ':d'
    display mode)
  - enter ':?' to get a list of special commands and mode switches
  Options:
  -t               trap exceptions in a repl, too
  -H|--no-history  do not save history to file (it is still read on
                   startup.)
  --name name      use name instead of the name of this script as part
                   of the history file name: ~/.\${name}_history
  -M module        use the given module (namespace or path)
  -m module        same as -M but don't complain about failures
";
    exit @_;
}
use Chj::xhome qw(xsafehome);
my @files;
my $opt_H;
my @opt_M;
my @opt_m;
my $opt_t;
for (my $i = 0; $i <= $#ARGV; $i++) {
    local $_ = $ARGV[$i];
    if (/^--?h(elp)?$/) {
        usage
    } elsif ($_ eq '--') {
        push @files, @ARGV[$i + 1 .. $#ARGV];
        last;
    } elsif ($_ eq '-H' or $_ eq '--no-history') {
        $opt_H = 1;
    } elsif ($_ eq '-t') {
        $opt_t = 1;
    } elsif (/^-M(.*)/) {
        if ($1) {
            push @opt_M, $1;
        } else {
            my $arg = $ARGV[++$i];
            defined $arg or usage "missing argument to -M";
            push @opt_M, $arg;
        }
    } elsif (/^-m(.*)/) {
        if ($1) {
            push @opt_m, $1;
        } else {
            my $arg = $ARGV[++$i];
            defined $arg or usage "missing argument to -m";
            push @opt_m, $arg;
        }
    } elsif (/^--name$/) {
        my $arg = $ARGV[++$i];
        defined $arg or usage "missing argument to --name";
        $myname = $arg;
    } elsif (/^-/) {
        warn "Unknown option '$_'\n";
        usage(1)
    } else {
        push @files, $_
    }
}
my $HISTFILE = xsafehome . "/.${myname}_history";
#my $MAXHISTLEN = 500;
eval { require Chj::BinHexOctDec; };
warn $@ if $@;
use Chj::Package::OfPath qw(package_of_path_or_package);
use FP::Repl::WithRepl qw(push_withrepl WithRepl_eval WithRepl_eval_e);
use FP::Carp;
push_withrepl(0) if $opt_t;
sub moduleoption_to_code {
    @_ == 1 or fp_croak_arity 1;
    my ($a) = @_;
    $a =~ s/([^=]+)//s or die "invalid -M option '$_'";
    my $path_or_package = $1;
    my $p               = package_of_path_or_package($path_or_package);
    "use " . do {
        if ($a =~ s/^=//s) {
            $p . " " . join(", ", map {"'$_'"} split /,/, $a)
        } else {
            $p
        }
    }
}
if (@opt_M) {
    my $code = join(";", map { moduleoption_to_code $_ } @opt_M);
    &WithRepl_eval("package $myname; " . $code . "; 1") or die $@;
}
for my $path_or_package (@opt_m) {
    eval moduleoption_to_code $path_or_package;
}
if (@files) {
    for (@files) {
        my ($res, $e, $is_error) = &WithRepl_eval_e($_, $myname);
        die $e if $is_error;
        print "$res\n";
    }
} else {
    require FP::Repl;
    FP::Repl::repl(
        maybe_historypath => ($opt_H ? undef : $HISTFILE),
        #maxhistlen        => $MAXHISTLEN,
        maybe_package => $myname
    );
}