#!/usr/bin/perl -w

use strict;
use Cwd;

# Usage:
#
# ./sync-all [-q] [-s] [--ignore-failure] [-r repo]
#            [--nofib] [--testsuite] [--checked-out] cmd [git flags]
#
# Applies the command "cmd" to each repository in the tree.
# sync-all will try to do the right thing for both git and darcs repositories.
#
# e.g.
#      ./sync-all -r http://darcs.haskell.org/ghc get
#          To get any repos which do not exist in the local tree
#
#      ./sync-all pull
#          To pull everything from the default repos
#
# -------------- Flags -------------------
#   -q says to be quite, and -s to be silent.
#
#   --ignore-failure says to ignore errors and move on to the next repository
#
#   -r repo says to use repo as the location of package repositories
#
#   --checked-out says that the remote repo is in checked-out layout, as
#   opposed to the layout used for the main repo.  By default a repo on
#   the local filesystem is assumed to be checked-out, and repos accessed
#   via HTTP or SSH are assumed to be in the main repo layout; use
#   --checked-out to override the latter.
#
#   --nofib, --testsuite also get the nofib and testsuite repos respectively
#
# ------------ Which repos to use -------------
# sync-all uses the following algorithm to decide which remote repos to use
#
#  It always computes the remote repos from a single base, $repo_base
#  How is $repo_base set?  
#    If you say "-r repo", then that's $repo_base
#    otherwise $repo_base is set by asking git where the ghc repo came
#    from, and removing the last component (e.g. /ghc.git/ of /ghc/).
#
#  Then sync-all iterates over the package found in the file
#  ./packages; see that file for a description of the contents.
# 
#    If $repo_base looks like a local filesystem path, or if you give
#    the --checked-out flag, sync-all works on repos of form
#          $repo_base/<local-path>
#    otherwise sync-all works on repos of form
#          $repo_base/<remote-path>
#    This logic lets you say
#      both    sync-all -r http://darcs.haskell.org/ghc-6.12 pull
#      and     sync-all -r ../HEAD pull
#    The latter is called a "checked-out tree".

# NB: sync-all *ignores* the defaultrepo of all repos other than the
# root one.  So the remote repos must be laid out in one of the two
# formats given by <local-path> and <remote-path> in the file 'packages'.

$| = 1; # autoflush stdout after each print, to avoid output after die

my $defaultrepo;
my @packages;
my $verbose = 2;
my $ignore_failure = 0;
my $checked_out_flag = 0;
my $get_mode;

my %tags;

# Figure out where to get the other repositories from.
sub getrepo {
    my $basedir = ".";
    my $repo;

    if (defined($defaultrepo)) {
        $repo = $defaultrepo;
        chomp $repo;
    } else {
        # Figure out where to get the other repositories from,
        # based on where this GHC repo came from.
        my $branch = `git branch | grep "\* " | sed "s/^\* //"`; chomp $branch;
        my $remote = `git config branch.$branch.remote`;         chomp $remote;
        $repo = `git config remote.$remote.url`;       chomp $repo;
    }

    my $repo_base;
    my $checked_out_tree;

    if ($repo =~ /^...*:/) {
        # HTTP or SSH
        # Above regex says "at least two chars before the :", to avoid
        # catching Win32 drives ("C:\").
        $repo_base = $repo;

        # --checked-out is needed if you want to use a checked-out repo
        # over SSH or HTTP
        if ($checked_out_flag) {
            $checked_out_tree = 1;
        } else {
            $checked_out_tree = 0;
        }

        # Don't drop the last part of the path if specified with -r, as
        # it expects repos of the form:
        #
        #   http://darcs.haskell.org
        #
        # rather than
        #   
        #   http://darcs.haskell.org/ghc
        #
        if (!$defaultrepo) {
            $repo_base =~ s#/[^/]+/?$##;
        }
    }
    elsif ($repo =~ /^\/|\.\.\/|.:(\/|\\)/) {
        # Local filesystem, either absolute or relative path
        # (assumes a checked-out tree):
        $repo_base = $repo;
        $checked_out_tree = 1;
    }
    else {
        die "Couldn't work out repo";
    }

    return $repo_base, $checked_out_tree;
}

sub parsePackages {
    my @repos;
    my $lineNum;

    open IN, "< packages" or die "Can't open packages file";
    @repos = <IN>;
    close IN;

    @packages = ();
    $lineNum = 0;
    foreach (@repos) {
        chomp;
        $lineNum++;
        if (/^([^# ]+) +([^ ]+) +([^ ]+) +([^ ]+) +([^ ]+)$/) {
            my %line;
            $line{"localpath"}  = $1;
            $line{"tag"}        = $2;
            $line{"remotepath"} = $3;
            $line{"vcs"}        = $4;
            $line{"upstream"}   = $5;
            push @packages, \%line;
        }
        elsif (! /^(#.*)?$/) {
            die "Bad content on line $lineNum of packages file: $_";
        }
    }
}

sub message {
    if ($verbose >= 2) {
        print "@_\n";
    }
}

sub warning {
    if ($verbose >= 1) {
        print "warning: @_\n";
    }
}

sub scm {
    my $dir = shift;
    my $scm = shift;
    my $pwd;

    if ($dir eq '.') {
        message "== running $scm @_";
    } else {
        message "== $dir: running $scm @_";
        $pwd = getcwd();
        chdir($dir);
    }

    system ($scm, @_) == 0
        or $ignore_failure
        or die "$scm failed: $?";

    if ($dir ne '.') {
        chdir($pwd);
    }
}

sub scmall {
    my $command = shift;
    
    my $localpath;
    my $tag;
    my $remotepath;
    my $scm;
    my $upstream;
    my $line;
    my $branch_name;
    my $subcommand;

    my $path;
    my $wd_before = getcwd;

    my $pwd;
    my @args;

    my ($repo_base, $checked_out_tree) = getrepo();

    my $is_github_repo = $repo_base =~ m/(git@|git:\/\/|https:\/\/)github.com/;

    parsePackages;

    @args = ();

    if ($command =~ /^remote$/) {
        while (@_ > 0 && $_[0] =~ /^-/) {
            push(@args,shift);
        }
        if (@_ < 1) { help(); }
        $subcommand = shift;
        if ($subcommand ne 'add' && $subcommand ne 'rm' && $subcommand ne 'set-url') {
            help();
        }
        while (@_ > 0 && $_[0] =~ /^-/) {
            push(@args,shift);
        }
        if (($subcommand eq 'add' || $subcommand eq 'rm') && @_ < 1) {
            help();
        } elsif (@_ < 1) { # set-url
            $branch_name = 'origin';
        } else {
            $branch_name = shift;
        }
    } elsif ($command eq 'new') {
        if (@_ < 1) {
            $branch_name = 'origin';
        } else {
            $branch_name = shift;
        }
    }

    push(@args, @_);

    for $line (@packages) {

        $localpath  = $$line{"localpath"};
        $tag        = $$line{"tag"};
        $remotepath = $$line{"remotepath"};
        $scm        = $$line{"vcs"};
        $upstream   = $$line{"upstream"};

        # Check the SCM is OK as early as possible
        die "Unknown SCM: $scm" if (($scm ne "darcs") and ($scm ne "git"));

        # We can't create directories on GitHub, so we translate
        # "package/foo" into "package-foo".
        if ($is_github_repo) {
            $remotepath =~ s/\//-/;
        }

        # Work out the path for this package in the repo we pulled from
        if ($checked_out_tree) {
            $path = "$repo_base/$localpath";
        }
        else {
            $path = "$repo_base/$remotepath";
        }

        if ($command =~ /^(?:g|ge|get)$/) {
            # Skip any repositories we have not included the tag for
            if (not defined($tags{$tag})) {
                $tags{$tag} = 0;
            }
            if ($tags{$tag} == 0) {
                next;
            }
            
            if (-d $localpath) {
                warning("$localpath already present; omitting")
                    if $localpath ne ".";
                if ($scm eq "git") {
                    scm ($localpath, $scm, "config", "core.ignorecase", "true");
                }
                next;
            }

            # Note that we use "." as the path, as $localpath
            # doesn't exist yet.
            if ($scm eq "darcs") {
                # The first time round the loop, default the get-mode
                if (not defined($get_mode)) {
                    warning("adding --partial, to override use --complete");
                    $get_mode = "--partial";
                }
                scm (".", $scm, "get", $get_mode, $path, $localpath, @args);
            }
            else {
                scm (".", $scm, "clone", $path, $localpath, @args);
                scm ($localpath, $scm, "config", "core.ignorecase", "true");
            }
            next;
        }

        if (-d "$localpath/_darcs") {
            if (-d "$localpath/.git") {
                die "Found both _darcs and .git in $localpath";
            }
            else {
                $scm = "darcs";
            }
        }
        else {
            if (-d "$localpath/.git") {
                $scm = "git";
            }
            elsif ($tag eq "") {
                die "Required repo $localpath is missing";
            }
            else {
                message "== $localpath repo not present; skipping";
            }
        }

        # Work out the arguments we should give to the SCM
        if ($command =~ /^(?:w|wh|wha|what|whats|whatsn|whatsne|whatsnew|status)$/) {
            if ($scm eq "darcs") {
                $command = "whatsnew";
            }
            elsif ($scm eq "git") {
                $command = "status";
            }
            else {
                die "Unknown scm";
            }

            # Hack around 'darcs whatsnew' failing if there are no changes
            $ignore_failure = 1;
            scm ($localpath, $scm, $command, @args);
        }
        elsif ($command =~ /^commit$/) {
            # git fails if there is nothing to commit, so ignore failures
            $ignore_failure = 1;
            scm ($localpath, $scm, "commit", @args);
        }
        elsif ($command =~ /^(?:pus|push)$/) {
            scm ($localpath, $scm, "push", @args);
        }
        elsif ($command =~ /^(?:pul|pull)$/) {
            scm ($localpath, $scm, "pull", @args);
        }
        elsif ($command =~ /^(?:s|se|sen|send)$/) {
            if ($scm eq "darcs") {
                $command = "send";
            }
            elsif ($scm eq "git") {
                $command = "send-email";
            }
            else {
                die "Unknown scm";
            }
            scm ($localpath, $scm, $command, @args);
        }
        elsif ($command =~ /^fetch$/) {
            scm ($localpath, $scm, "fetch", @args);
        }
        elsif ($command =~ /^new$/) {
            my @scm_args = ("log", "$branch_name..");
            scm ($localpath, $scm, @scm_args, @args);
        }
        elsif ($command =~ /^remote$/) {
            my @scm_args;
            if ($subcommand eq 'add') {
                @scm_args = ("remote", "add", $branch_name, $path);
            } elsif ($subcommand eq 'rm') {
                @scm_args = ("remote", "rm", $branch_name);
            } elsif ($subcommand eq 'set-url') {
                @scm_args = ("remote", "set-url", $branch_name, $path);
            }
            scm ($localpath, $scm, @scm_args, @args);
        }
        elsif ($command =~ /^grep$/) {
            # Hack around 'git grep' failing if there are no matches
            $ignore_failure = 1;
            scm ($localpath, $scm, "grep", @args)
                unless $scm eq "darcs";
        }
        elsif ($command =~ /^clean$/) {
            scm ($localpath, $scm, "clean", @args)
                unless $scm eq "darcs";
        }
        elsif ($command =~ /^reset$/) {
            scm ($localpath, $scm, "reset", @args)
                unless $scm eq "darcs";
        }
        elsif ($command =~ /^config$/) {
            scm ($localpath, $scm, "config", @args)
                unless $scm eq "darcs";
        }
        else {
            die "Unknown command: $command";
        }
    }
}


sub help()
{
        # Get the built in help
        my $help = <<END;
What do you want to do?
Supported commands:

 * whatsnew
 * commit
 * push
 * pull
 * get, with options:
  * --<package-tag>
  * --complete
  * --partial
 * fetch
 * send
 * new
 * remote add <branch-name>
 * remote rm <branch-name>
 * remote set-url [--push] <branch-name>
 * grep
 * clean
 * reset
 * config

Available package-tags are:
END

        # Collect all the tags in the packages file
        my %available_tags;
        open IN, "< packages" or die "Can't open packages file";
        while (<IN>) {
            chomp;
            if (/^([^# ]+) +(?:([^ ]+) +)?([^ ]+) +([^ ]+)/) {
                if (defined($2) && $2 ne "-") {
                    $available_tags{$2} = 1;
                }
            }
            elsif (! /^(#.*)?$/) {
                die "Bad line: $_";
            }
        }
        close IN;
        
        # Show those tags and the help text
        my @available_tags = keys %available_tags;
        print "$help@available_tags\n";
        exit 1;
}

sub main {
    if (! -d ".git" || ! -d "compiler") {
        die "error: sync-all must be run from the top level of the ghc tree."
    }

    $tags{"-"} = 1;
    $tags{"dph"} = 1;

    while ($#_ ne -1) {
        my $arg = shift;
        # We handle -q here as well as lower down as we need to skip over it
        # if it comes before the source-control command
        if ($arg eq "-q") {
            $verbose = 1;
        }
        elsif ($arg eq "-s") {
            $verbose = 0;
        }
        elsif ($arg eq "-r") {
            $defaultrepo = shift;
        }
        elsif ($arg eq "--ignore-failure") {
            $ignore_failure = 1;
        }
        elsif ($arg eq "--complete" || $arg eq "--partial") {
            $get_mode = $arg;
        }
        # Use --checked-out if the remote repos are a checked-out tree,
        # rather than the master trees.
        elsif ($arg eq "--checked-out") {
            $checked_out_flag = 1;
        }
        # --<tag> says we grab the libs tagged 'tag' with
        # 'get'. It has no effect on the other commands.
        elsif ($arg =~ m/^--no-(.*)$/) {
            $tags{$1} = 0;
        }
        elsif ($arg =~ m/^--(.*)$/) {
            $tags{$1} = 1;
        }
        else {
            unshift @_, $arg;
            if (grep /^-q$/, @_) {
                $verbose = 1;
            }
            last;
        }
    }

    if ($#_ eq -1) {
        help();
    }
    else {
        # Give the command and rest of the arguments to the main loop
        scmall @_;
    }
}

main(@ARGV);