#!/bin/bash
#
# schhist2web - Web-browseable graphical revision history of schematics
#
# Written 2010 by Werner Almesberger
# Copyright 2010 Werner Almesberger
#
# 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.
#


OUTDIR=_out
THUMB_OPTS="-w 3 -d 60 -c 0.5,0.5,0.5 -n 1,1,0"
BG_COLOR="f0f0ff"
FNAME_COLOR="#b0f0ff"
SEP_COLOR="#000000"


shrink()
{
    pnmscale -width 120 "$@" || exit
}


pngdiff()
{
    # pngdiff preproc outfile arg ...
    pp="$1"
    of="$2"
    shift 2
    if ! PATH=$PATH:`dirname $0`/ppmdiff ppmdiff "$@" "$out/_tmp"; then
	rm -f "$out/_tmp"
	return 1
    fi
    $pp "$out/_tmp" | pnmtopng >"$of"
    rm "$out/_tmp"
}


symlink()
{
    local old=$1 new=$2
    local src=`dirname "$new"`/$old

    if [ -L "$src" ]; then
	ln -sf "`readlink \"$src\"`" "$new"
    else
	ln -sf "$old" "$new"
    fi
}


commit_entry()
{
    # usage: commit_entry <base-dir> <commit>
    # note: the repository's base in $dir must be provided by the caller

    local dir=$1 next=$2

    cat <<EOF
<TABLE bgcolor="$SEP_COLOR" cellspacing=0 width="100%"><TR><TD></TABLE>
EOF
    echo "<PRE>"
    ( cd "$dir" && git show --pretty=short --quiet $next; ) |
      if [ -z "$SCHHIST_COMMIT_TEMPLATE" ]; then
	cat
      else
	url=`echo "$SCHHIST_COMMIT_TEMPLATE" | sed "s/{}/$next/g"`
	sed "s|^commit |<A href=\"$url\">commit</a> |"
      fi |
      sed '/^<.*>commit</n;s/&/&amp;/g;s/</\&lt;/g;s/>/\&gt;/g'
    echo "</PRE>"
}


usage()
{
    cat <<EOF 2>&1
usage: $0 [-c cache-dir] [-n] [-S] [top-dir] [top-schem] [out-dir]

  top-dir       top-level directory of the git archive (default: locate it)
  top-schem     root sheet of the schematics (default: locate it in top-dir)
  out-dir       output directory (default: $OUTDIR)
  -c cache-dir  cache directory (default: same as out-dir)
  -n            don't use previous cache content (rebuild the cache)
  -S            sanitize KiCad profile
EOF
    exit 1
}


# --- Parse command-line options ----------------------------------------------


no_cache=false
sanitize=

while true; do
    case "$1" in
    -n)	no_cache=true
	shift;;
    -c)	[ -z "$1" ] && usage
	cache="$1"
	shift 2;;
    -S)	sanitize=-S
	shift;;
    -*) usage;;
    *)	break;;
    esac
done


# --- Interpret the command-line arguments ------------------------------------


if [ ! -z "$1" -a -d "$1/.git" ]; then
    dir="$1"
    shift
else
    dir=.
    while [ ! -d $dir/.git ]; do
	if [ $dir -ef $dir/.. ]; then
	    echo "no .git/ directory found in hierarchy" 1>&2
	    exit 1
	fi
	dir=$dir/..
    done
    echo "found top-dir: $dir" 1>&2
fi

if [ ! -z "$1" -a -f "$dir/$1" -a \
  -f "$dir/${1%.sch}.pro" ]; then
    sch="$1"
    shift
else
    for n in "$dir"/*.sch; do
	[ -f "${n%.sch}.pro" ] || continue
	if [ ! -z "$sch" ]; then
	    echo "multiple choices for top-level .sch file" 1>&2
	    exit 1
	fi
	sch="$n"
    done
    if [ -z "$sch" -o "$sch" = "$dir/*.sch" ]; then
	echo "no candidate for top-level .sch file found" 1>&2
	exit 1
    fi
    echo "found root sheet: $sch" 1>&2
fi

if [ ! -z "$1" ] && [ ! -e "$1" ] || [ -d "$1" -a ! -d "$1"/.git ]; then
    out="$1"
    shift
else
    out=$OUTDIR
fi
[ -z "$cache" ] && cache="$out"

[ -z "$1" ] || usage


# --- Set up some variables and the directories for cache and output ----------


PATH=`dirname "$0"`:"$PATH"
first=`gitenealogy "$dir" "$sch" | sed '$s/ .*//p;d'`
schname=`gitenealogy "$dir" "$sch" | sed '$s/^.* //p;d'`

rm -rf "$out/diff_*" "$out/thumb_*" "$out/names"
$no_cache && rm -rf "$cache"
mkdir -p "$out/names"
mkdir -p "$cache"

ppmmake '#e0e0e0' 5 30 | pnmtopng >"$out"/unchanged.png


# --- Generate/update the cache -----------------------------------------------


head=
for n in $first `cd "$dir" && git rev-list --reverse $first..HEAD`; do
    ( cd "$dir" && git show  --pretty=format:'' --name-only $n; ) |
      egrep -q '\.sch$|\.pro$|\.lib$' || continue
    echo Processing $n
    new=`gitenealogy "$dir" "$sch" | sed "/^$n /s///p;d"`
    if [ ! -z "$new" ]; then
	echo Name change $schname to $new 1>&2
	schname="$new"
    fi
    trap "rm -rf \"$cache/ppm_$n\" \"$cache/fat_$n\"" 0
    if [ ! -d "$cache/ppm_$n" ]; then
	rm -rf "$cache/ppm_$n"
	mkdir "$cache/ppm_$n"
	#
	# potential optimization here: remember Postscript files from previous
	# run (or their md5sum) and check if they have changed. If not, skip
	# the ghostscript run and just put a symlink, replacing the less
	# efficient optimization below.
	#
	gitsch2ppm $sanitize -k "$dir" "$schname" $n "$cache/ppm_$n" || exit
	gitsch2ppm -c -w 500 "$dir" "$schname" $n "$cache/fat_$n" || exit
    fi
    for m in "$cache/ppm_$n/"*; do
	[ "$m" = "$cache/ppm_$n/*" ] && break
	if [ ! -z "$head" ]; then
	    prev="$cache/ppm_$head"/`basename "$m"`
	    if [ -r "$prev" ] && cmp -s "$prev" "$m"; then
		symlink "../ppm_$head/`basename \"$m\"`" "$m"
		symlink "../fat_$head/`basename \"$m\"`" \
		  "$cache/fat_$n/`basename \"$m\"`"
	    fi
	fi
	touch "$out/names/`basename \"$m\" .ppm`"
    done
    trap 0
    head=$n
done

if [ -z "$head" ]; then
    echo "no usable head found" 2>&1
    exit 1
fi


# --- Title of the Web page and table header ----------------------------------


index="$out/index.html"
{
    cat <<EOF
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<HTML>
EOF
    if [ ! -z "$SCHHIST_TITLE" ]; then
	echo "<TITLE>$SCHHIST_TITLE</TITLE>"
    fi
    echo "<BODY>"
    if [ ! -z "$SCHHIST_TITLE" ]; then
	echo "<H1>"
	[ -z "$SCHHIST_HOME_URL" ] || echo "<A href=\"$SCHHIST_HOME_URL\">"
	echo "$SCHHIST_TITLE"
	[ -z "$SCHHIST_HOME_URL" ] || echo "</A>"
	echo "</H1>"
    fi
    cat <<EOF
<TABLE bgcolor="$BG_COLOR" callpadding=1>
<TR bgcolor="$FNAME_COLOR">
EOF
    while read m; do
	echo "<TD><B>$m</B>"
    done < <(ls -1 "$out/names")
} >"$index"


# --- Diff all the revisions, newest to oldest --------------------------------


next="$head"
for n in `cd "$dir" && git rev-list $first..HEAD~1` $first; do
    [ -d "$cache/ppm_$n" ] || continue
    empty=true
    s="<TR>"
    mkdir -p "$out/diff_$next" "$out/thumb_$next"
    while read m; do
	a="$cache/ppm_$n/$m.ppm"
	fat_a="$cache/fat_$n/$m.ppm"
	b="$cache/ppm_$next/$m.ppm"
	fat_b="$cache/fat_$next/$m.ppm"
	diff="$out/diff_$next/$m.png"
	thumb="$out/thumb_$next/$m.png"

	if [ -f "$a" -a -f "$b" ]; then
	    s="$s<TD align=\"center\" valign=\"middle\">"
	    if ! pngdiff cat "$diff" "$a" "$b"; then
		s="$s<IMG src=\"unchanged.png\""
		continue
	    fi
	    pngdiff shrink "$thumb" -f $THUMB_OPTS "$fat_a" "$fat_b" \
	      "$a" "$b" || exit
	elif [ -f "$a" ]; then
	    s="$s<TD>"
	    pngdiff cat "$diff" -f -c 1,0,0 "$a" "$a" || exit
	    pngdiff shrink "$thumb" -f $THUMB_OPTS -c 1,0,0 "$fat_a" "$fat_a" \
	      || exit
	elif [ -f "$b" ]; then
	    s="$s<TD>"
	    pngdiff cat "$diff" -f -c 0,1,0 "$b" "$b" || exit
	    pngdiff shrink "$thumb" -f $THUMB_OPTS -c 0,1,0 "$fat_b" "$fat_b" \
	      || exit
	else
	    s="$s<TD>"
	    continue
	fi
	echo "$s" >>"$index"
	s=
	empty=false
	echo "<A href=\"diff_$next/$m.png\"><IMG src=\"thumb_$next/$m.png\"></A>" >>"$index"
    done < <(ls -1 "$out/names")
    if ! $empty; then
 	echo "$s<TD valign=\"middle\">" >>"$index"
	commit_entry "$dir" $next >>"$index"
    fi
    next=$n
done


# --- Add creation entries for all files in the first commit ------------------


if [ -d "$cache/ppm_$next" ]; then	# could this ever be false ?
    empty=true
    echo "<TR>" >>"$index"
    mkdir -p "$out/diff_$next" "$out/thumb_$next"
    while read m; do
	ppm="$cache/ppm_$next/$m.ppm"
	fat="$cache/fat_$next/$m.ppm"
	diff="$out/diff_$next/$m.png"
	thumb="$out/thumb_$next/$m.png"

	echo "<TD>" >>"$index"
	[ -f "$ppm" ] || continue
	pngdiff cat "$diff" -f -c 0,1,0 "$ppm" "$ppm" || exit
	pngdiff shrink "$thumb" -f $THUMB_OPTS -c 0,1,0 "$fat" "$fat" \
	      || exit
	empty=false
	echo "<A href=\"diff_$next/$m.png\"><IMG src=\"thumb_$next/$m.png\"></A>" >>"$index"
    done < <(ls -1 "$out/names")
    if ! $empty; then
 	echo "<TD valign=\"middle\">" >>"$index"
	commit_entry "$dir" $next >>"$index"
    fi
fi


# --- Finish ------------------------------------------------------------------


cat <<EOF >>"$index"
</TABLE>
<HR>
`date -u '+%F %X'` UTC
</BODY>
</HTML>
EOF