#!/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()
{
  # commands to invoke to output heading, index lines and index footers
  # (intended to close headings)
  headout="$1"
  lineout="$2"
  footout="$3"

  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" -P < <( echo "$subject"; echo ) )"

    [ "$prevdate" == "$dategroup" ] || {
      [ -z "$prevdate" ] || $footout
      $headout "$dategroup"
    }

    $lineout "$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

  $footout

  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