#!/usr/bin/env perl

#   Copyright (c) MediaTek USA Inc., 2020
#
#   This program is free software;  you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or (at
#   your option) any later version.
#
#   This program is distributed in the hope that it will be useful, but
#   WITHOUT ANY WARRANTY;  without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#   General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program;  if not, see
#   <http://www.gnu.org/licenses/>.
#
#
# p4udiff
#
#   This script extracts a unified-diff between two Perforce changelists.

use strict;
use DateTime;
use Getopt::Long;

package P4File;

sub new
{
    my $class       = shift;
    my $description = shift;
    if ($description =~
        m/([^#]+)#([0-9]+)\s+-\s+(\S+)\s+change\s+([0-9]+)\s+\(([^)]+)\).*$/) {
        my $self = {};
        bless $self, $class;

        $self->{path}       = $1;
        $self->{rev}        = $2;
        $self->{action}     = $3;
        $self->{changelist} = $4;
        $self->{type}       = $5;

        return $self;
    }
    return undef;
}

sub path
{
    my $self = shift;
    return $self->{path};
}

sub rev
{
    my $self = shift;
    return $self->{rev};
}

sub action
{
    my $self = shift;
    return $self->{action};
}

sub changelist
{
    my $self = shift;
    return $self->{changelist};
}

sub type
{
    my $self = shift;
    return $self->{type};
}

package P4FileList;

sub new
{
    my ($class, $include, $exclude) = @_;
    my $self = [{}, $include, $exclude];
    bless $self, $class;

    return $self;
}

sub include_me
{
    my ($path, $include, $exclude) = @_;

    if (defined($exclude)) {
        foreach my $pat (@$exclude) {
            return 0
                if $path =~ /$pat/;
        }
    }
    return 1
        if (!defined($include) || 0 == scalar(@$include));

    foreach my $pat (@$include) {
        return 1
            if ($path =~ /$pat/);
    }
    return 0;
}

sub append
{
    my $self  = shift;
    my $entry = shift;

    return $self if (!defined($entry));
    my ($hash, $include, $exclude) = @$self;
    my $key = $entry->path();
    if (defined($hash->{$key})) {
        warn("WARNING: skipping duplicated path $key\n");
        return $self;
    }
    $hash->{$key} = $entry
        if include_me($key, $include, $exclude);
    return $self;
}

sub files
{
    my $self = shift;
    return sort keys %{$self->[0]};
}

sub get
{
    my $self = shift;
    my $key  = shift;

    if (!defined($self->[0]->{$key})) {
        return undef;
    }
    return $self->[0]->{$key};
}

sub remove
{
    my $self = shift;
    my $key  = shift;
    delete $self->[0]->{$key};
    return $self;
}

package main;

my @exclude_patterns;
my @include_patterns;
my $suppress_unchanged;
my $ignore_whitespace;

if (!GetOptions("exclude=s"    => \@exclude_patterns,
                "include=s"    => \@include_patterns,
                'b|blank'      => \$ignore_whitespace,
                'no-unchanged' => \$suppress_unchanged) ||
    3 != scalar(@ARGV)
) {
    print(STDERR<<EOF
usage: [(--exclude|include) regexp[,regexp]] [-b] [--no-unchanged] sandbox_directory base_changelist current_changelist
 'exclude' wins if both exclude and include would match.
 'current_changelist' may be a changelist number or "sandbox".
 "sandbox" indicates that there may be changes in 'sandbox_directory' which have not ben committed to perforce yet.
 '-b' ignores whitespace changes
EOF
    );
    exit(1);
}
@exclude_patterns = split(',', join(',', @exclude_patterns));
@include_patterns = split(',', join(',', @include_patterns));

my $top_directory   = shift @ARGV;
my $base_changelist = shift @ARGV;
my $curr_changelist = shift @ARGV;
my $base_files      = P4FileList->new(\@include_patterns, \@exclude_patterns);
my $curr_files      = P4FileList->new(\@include_patterns, \@exclude_patterns);

# need "/..." on the pathname if this is a directory.
#  - depot_path may not be the same as the client workspace path.
#  - If the name is local, then append if it is a directory - otherwise, ask P4
# Don't go to P4 unless necessary - as the interaction is pretty slow.

# Ask the Perforce server to lookup the path and append a directory recursion
# pattern if the depot_path is not a file_type.
my $p4_path = $top_directory;
if (-e $p4_path) {
    $p4_path .= "/..."
        if (-d $p4_path);
} else {
    system("p4 fstat $top_directory|grep depotFile >/dev/null 2>&1");
    if (($? >> 8) != 0) {
        $p4_path .= "/...";
    }
}

if (open(HANDLE, "-|", "p4 files ${p4_path}\@$base_changelist")) {
    DIFF_FILE:
    while (my $line = <HANDLE>) {
        chomp $line;
        s/\015$//;

        $base_files->append(P4File->new($line));
    }
    close(HANDLE) or die("unable to close p4 files (baseline) pipe: $!\n");
    if (0 != $?) {
        $? & 0x7F &
            die("p4 files (baseline) died from signal ", ($? & 0x7F), "\n");
        die("p4 files (baseline) exited with error ", ($? >> 8), "\n");
    }
}

my $curr = $curr_changelist eq "sandbox" ? "" : "\@$curr_changelist";
if (open(HANDLE, "-|", "p4 files ${p4_path}$curr")) {
    DIFF_FILE:
    while (my $line = <HANDLE>) {
        chomp $line;
        s/\015$//;
        $curr_files->append(P4File->new($line));
    }
    close(HANDLE) or die("unable to close p4 files (current) pipe: $!\n");
    if (0 != $?) {
        $? & 0x7F &
            die("p4 files (current) died from signal ", ($? & 0x7F), "\n");
        die("p4 files (current) exited with error ", ($? >> 8), "\n");
    }
}

my @unchanged;

# prune files at the same rev; no difference to report
foreach my $f ($base_files->files()) {
    my $b = $base_files->get($f);
    my $c = $curr_files->get($f);

    if (defined($c) &&
        $b->rev() eq $c->rev()       &&
        $b->action() eq $c->action() &&
        $b->changelist() eq $c->changelist()) {
        $curr_files->remove($f);
        $base_files->remove($f);
        push(@unchanged, $c)
            unless ($c->action() eq 'delete' ||
                    $c->type() eq 'binary');
    }
}

# prune files already deleted in base list
foreach my $f (grep {
                   $base_files->get($_)->action() eq "delete" ||
                       $base_files->get($_)->action() eq "move/delete"
               } $base_files->files()
) {
    my $b = $base_files->get($f);
    my $c = $curr_files->get($f);

    if (defined($c) && $b->action() eq $c->action()) {
        # deleted again in curr with a different rev
        $curr_files->remove($f);
    }

    $base_files->remove($f);
}

# prune files deleted in curr list
foreach my $f (grep {
                   $curr_files->get($_)->action() eq "delete" ||
                       $curr_files->get($_)->action() eq "move/delete"
               } $curr_files->files()
) {
    my $c = $curr_files->get($f);

    $curr_files->remove($f);
}

my %union;

foreach my $k ($base_files->files()) {
    #my $b = $base_files->get($k);
    #printf("base: %s#%d %s change %d\n", $k, $b->rev(), $b->action(), $b->changelist());
    $union{$k} = 1;
}
foreach my $k ($curr_files->files()) {
    #my $b = $curr_files->get($k);
    #printf("curr: %s#%d %s change %d\n", $k, $b->rev(), $b->action(), $b->changelist());
    $union{$k} = 1;
}
#exit;

#my $workspace = `p4 -F \%clientRoot\% -ztag info`;
my $where =
    `p4 where $p4_path`;    # need the "..." in the path or p4 gets confused
$where =~ s/\/\.\.\.//g;
my ($depot_path, $workspace_path, $sandbox_path) = split(' ', $where);

sub reloc
{
    my $path = shift;
    $path =~ s/$depot_path/$sandbox_path/;
    return $path;
}

foreach my $f (sort keys %union) {
    my $b = $base_files->get($f);
    my $c = $curr_files->get($f);

    if (defined($b) && !defined($c)) {
        # deleted
        next if ($b->type() eq "binary");
        printf("p4 diff $f#%d $f\n", $b->rev());
        printf("index %d..0\n", $base_changelist);
        printf("--- %s\n", reloc($f));
        printf("+++ /dev/null\n");
        # p4 print -q $b->path() . '#' . $b->rev() |sed -e 's/^/-/'
        my @lines;
        open(HANDLE, "-|", "p4", "print", "-q", $b->path() . '#' . $b->rev())
            or
            die("p4 print failed: $!\n");
        while (my $line = <HANDLE>) {
            chomp $line;
            $line =~ s/^/-/;
            push @lines, $line;
        }
        close(HANDLE) or die("unable to close p4 print pipe: $!\n");
        if (0 != $?) {
            $? & 0x7F & die("p4 print died from signal ", ($? & 0x7F), "\n");
            die("p4 print exited with error ", ($? >> 8), "\n");
        }
        printf("@@ 1,%d 0,0 @@\n", scalar(@lines));
        printf("%s\n", join("\n", @lines));
    } elsif (!defined($b) && defined($c)) {
        # added
        next if ($c->type() eq "binary");
        printf("p4 diff $f $f#%d\n", $c->rev());
        printf("new file mode\n");
        printf("index 0..%d\n", $curr_changelist);
        printf("--- /dev/null\n");
        printf("+++ %s\n", reloc($f));
        my @lines;
        open(HANDLE, "-|", "p4", "print", "-q", $c->path() . '#' . $c->rev())
            or
            die("p4 print failed: $!\n");

        while (my $line = <HANDLE>) {
            chomp $line;
            $line =~ s/^/+/;
            push @lines, $line;
        }
        close(HANDLE) or die("unable to close p4 print pipe: $!\n");
        if (0 != $?) {
            $? & 0x7F & die("p4 print died from signal ", ($? & 0x7F), "\n");
            die("p4 print exited with error ", ($? >> 8), "\n");
        }
        printf("@@ 0,0 1,%d @@\n", scalar(@lines));
        printf("%s\n", join("\n", @lines));
    } elsif (defined($b) && defined($c)) {
        # check diff
        next if ($b->type() eq "binary" || $c->type() eq "binary");
        # "p4 diff $ignore_whitespace -du ". $c->path() . '#' . $c->rev() . " " . $b->path() . '#' . $b->rev()
        printf("p4 diff $f#%d $f#%d\n", $b->rev(), $c->rev());
        printf("index %d..%d\n", $base_changelist, $curr_changelist);
        my @lines;
        my @cmd = ("p4", "diff", "-du",
                   $b->path() . '#' . $b->rev(),
                   $c->path() . '#' . $c->rev());
        splice(@cmd, 2, 0, '-db') if $ignore_whitespace;
        open(HANDLE, "-|", @cmd) or
            die("p4 diff failed: $!\n");
        while (my $line = <HANDLE>) {
            chomp $line;
            if ($line =~ m/^(---|\+\+\+)/) {
                $line =~ s/^(---\s+\S+).*$/$1/;
                $line =~ s/^(\+\+\+\s+\S+).*$/$1/;
                $line = reloc($line);
            }
            printf("%s\n", $line);
        }
        close(HANDLE) or die("unable to close p4 diff pipe: $!\n");
        if (0 != $?) {
            $? & 0x7F & die("p4 diff died from signal ", ($? & 0x7F), "\n");
            die("p4 diff exited with error ", ($? >> 8), "\n");
        }
    } else {
        warn("WARNING: not in base or current for $f\n");
    }
}

exit 0 if defined($suppress_unchanged);

foreach my $f (@unchanged) {
    my $name = $f->path();
    next
        unless P4FileList::include_me($name, \@include_patterns,
                                      \@exclude_patterns);
    printf("p4 diff $name#%d $name\n", $f->rev());
    printf("=== %s\n", reloc($name));
}