#!/bin/bash
#
# Generates HTML from repository commit messages
#
#  Copyright (C) 2012  Mike Gerwitz
#
#  This file is part of repo2html.
#
#  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 3 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/>.
# #

declare -xr repotype="${1?Missing repository type}"
declare -xr path_out="${2?Missing output path}"

# provide default message formatter if necessary
msgfmt="${msgfmt:-./msgfmt}"

# default template path (the former is exported so that templates themselves may
# make use of default templates)
declare -xr path_default_tpl=./tpl
declare -xr path_tpl="${path_tpl:-$path_default_tpl}"

resolv-template()
{
  name="$1"
  [ -x "$path_tpl/$name" ] \
    && echo "$path_tpl/$name" \
    || echo "$path_default_tpl/$name"
}
apply-template()
{
  $( resolv-template "$1" )
}
exec-template()
{
  exec $( resolv-template "$1" )
}

# allows custom templates to invoke the default template (say, to set/override
# options)
resume-default()
{
  exec "$path_default_tpl/$1"
}


# generates output filename
outfgen()
{
  ts="${1?Missing timestamp}"
  id="${2?Missing commit id}"
  ext="${3:+.$3}"

  dateout="$( ./tsdate "$ts" %Y-%m-%d )"
  month="$( ./tsdate "$ts" %m )"
  year="${dateout%%-*}"

  echo "$year/$month/$id$ext"
}


# performs index generation; by separating this into a procedure, we allow the
# template to invoke it at any point and further process the output
do-index()
{
    prevdate=
    lastts=
    firstyear=0
    lastyear=0
    lasthash=

    # generate index
    while read hash commit ts id subject; do
      # ignore commits that begin with ':'
      [[ "$subject" == :* ]] && {
        echo "Ignoring $commit: $subject" >&2
        continue
      }

      echo "Found $commit: $subject" >&2

      dateout="$( ./tsdate "$ts" %Y-%m-%d )"
      dategroup="${dateout%-*}"
      day="${dateout##*-}"
      month="$( ./tsdate "$ts" %m )"
      year="${dateout%%-*}"

      # commits are ordered by date desc
      lasthash="${lasthash:-$hash}"
      lastts="${lastts:-$ts}"
      lastyear="${lastyear:-$year}"
      firstyear="$year"

      pagefile="$( outfgen "$ts" "$id" "$html_ext" )"
      fmtsubject="$( "$msgfmt" < <( echo "$subject"; echo ) )"

      [ "$prevdate" == "$dategroup" ] || {
        echo "<h3 id="$dategroup">$dategroup</h3>"
      }

      printf '<ul><li>(%s) <a href="%s">%s</a></li></ul>' \
        "$day" "$pagefile" "$fmtsubject"

      prevdate="$dategroup"

      # create the containing directory (if it does not yet exist and then
      # generate the commit page
      mkdir -p "$( dirname "$path_out/$pagefile" )" \
        && (
          # make the majority of the data available as environment variables
          # (for convenience), lowercase so as not to be conflict with
          # conventional environment variables
          export hash commit id subject="$fmtsubject" timestamp="$ts"
          export dategroup month day year
          export path_root='../../'

          # invoke template
          "$repotype"/commit2html "$commit" | apply-template commit
        ) > "$path_out/$pagefile" \
        && ./hashcache "$hash" "$pagefile"
    done

    yearrange="$firstyear"
    if [ "$lastyear" -gt "$firstyear" ]; then
      yearrange="$firstyear&ndash;$lastyear"
    fi
}

# let the template finish
export -f do-index resolv-template apply-template exec-template resume-default \
  outfgen
exec-template index