#!/usr/bin/env perl

use strict;
use warnings;
use Cwd;

my (@data, @authors, @repos, @changed) = ((), (), (), ());
# Syntax: git-hist [author (default: whoami)] [number of weeks (default 10 / all 0)]";
my $author = `whoami`;
my $weeks = 10;
my $rootdir = getcwd;
my $totalcommits = 0;
if (scalar @ARGV) {
  foreach my $arg (@ARGV) {
    if ($arg =~ /^\d+$/) {
      $weeks = $arg;
    } else {
      $author = $arg;
    }
  }
}
chomp($author);

# Make sure there are repositories to use
if (-d ".git") {
  push @repos, ".";
} else {
  opendir(my $dh, ".") || die "can't open local dir: $!";
  @repos = grep { /^[^\.]/ && -d "$_/.git" } readdir($dh);
  closedir $dh;
}
die "Directory (or subs) not git repo\n" unless (scalar @repos);
&main();
exit;

#####################################################
sub main() {
  # Each week
  my $week = 0;
  while ($week <= $weeks) {
    # Adjust for non-zero week list
    $week++ if ($weeks != 0 and $week == 0);
    print "\rParsing week: $week" if $week;
    my $commits = 0;
    # For each repo
    for my $repo (@repos) {
      #print "REPO: $repo\n";
      my $log = &get_weeklog($repo, $author, $week);
      #print "LOG: [$log]\n";
      my $this = &get_commits($log);
      #print "COMMITS: $this\n";
      if ($this and ! &find($repo, \@changed)) {
        #print "ADDING REPO\n";
        push @changed, $repo;
      }
      &get_authors($log);
      $commits += $this;
    }
    push @data, $commits;
    last if ($weeks == 0);
    $week++;
  }
  print "\n\n";

  # Log
  &print_report();
}

######################
sub print_report() {
  return if ($weeks > 0 && scalar @data != $weeks);

  # Weekly histogram
  for my $week (0..$weeks-1) {
    printf("%02d week [%02d]: ", $week, $data[$week]);
    for (1..$data[$week]) {
      print "*";
    }
    print "\n";
  }

  # Summary
  print "\nTotal commits: ";
  printf("%3d", $totalcommits);
  print "\n Repositories: ";
  printf("%3d ", scalar @changed);
  &dump(\@changed);
  print "\n      Authors: ";
  printf("%3d ", scalar @authors);
  &dump(\@authors);
  print "\n";
}

######################
sub get_weeklog() {
  my ($repo, $author, $week) = @_;
  # Author
  my $cmd = "git shortlog -s -n ".
            "--author='$author' ";
  # And week (if available)
  if ($week) {
    my $prev = $week-1;
    $cmd .= "--since='$week.week' ".
            "--until='$prev.week'";
  }
  # Run command
  chdir($repo);
  my $log = `$cmd`;
  chdir($rootdir);
  return $log;
}

######################
sub get_commits() {
  my ($log) = @_;
  my $commits = 0;
  foreach my $line (split(/\n/, $log)) {
    my ($this) = ($line =~ /(\d+)/);
    $commits += $this;
  }
  $totalcommits += $commits;
  return $commits;
}

######################
sub get_authors() {
  my ($log) = @_;
  foreach my $line (split(/\n/, $log)) {
    my ($author) = ($line =~ /\d+\s+(\w.*)/);
    if (!&find($author, \@authors)) {
      push @authors, $author;
    }
  }
}

######################
sub find() {
  my ($elm, $array) = @_;
  foreach my $e (@$array) {
    return 1 if ($e eq $elm);
  }
  return 0;
}

######################
sub dump() {
  my ($array) = @_;
  return if (!scalar @{$array});
  my $out = "";
  foreach my $i (@$array) {
    $out .= "$i, ";
  }
  $out =~ s/, $//;
  print $out;
}