#!/usr/bin/env bash
#
# mfprep tag1 [tag2]
#
# Find commits in bugfix-2.1.x that are not yet in 2.0.x.
#
# Specify a version tag to start from, and optional version tag to end at.
# For bugfix-2.1.x the tag will be prefixed by dev- to distinguish it from the version tag,
# so at every release be sure to create a dev- tag and publish it to origin.
#

SED=$(which gsed sed | head -n1)
SELF=`basename "$0"`
DRYRUN=0

[[ $# < 1 || $# > 2 ]] && { echo "Usage $SELF tag1 [tag2]" ; exit 1 ; }

TAG1=$1
TAG2=${2:-"HEAD"}

DEST=2.1.x

# Validate that the required tags exist

MTAG=`git tag | grep -e "^dev-$TAG1\$"`
[[ -n "$MTAG" ]] || { echo "Can't find tag dev-$TAG1" ; exit 1 ; }
MTAG=`git tag | grep -e "^$TAG1\$"`
[[ -n "$MTAG" ]] || { echo "Can't find tag $TAG1" ; exit 1 ; }

# Generate log of recent commits for bugfix-2.1.x and DEST

TMPDIR=`mktemp -d`
LOGB="$TMPDIR/log-bf.txt"
LOG2="$TMPDIR/log-2x.txt"
TMPF="$TMPDIR/tmp.txt"
SCRF="$TMPDIR/update-$DEST.sh"

git checkout bugfix-2.1.x
git log --pretty="[%h] %s" dev-$TAG1..$TAG2 | grep -v '\[cron\]' | $SED '1!G;h;$!d' >"$LOGB"

git checkout $DEST
git log --pretty="[%h] %s" $TAG1..$TAG2 | $SED '1!G;h;$!d' >"$LOG2" || { echo "Can't find tag dev-$TAG1" ; exit 1 ; }

# Go through commit text from DEST removing all matches from the bugfix log

cat "$LOG2" | while read line; do
  if [[ $line =~ \(((#[0-9]{5}),* *)((#[0-9]{5}),* *)?((#[0-9]{5}),* *)?((#[0-9]{5}),* *)?((#[0-9]{5}),* *)?((#[0-9]{5}),* *)?\)$ ]]; then
    PATT=""
    for i in ${!BASH_REMATCH[@]}; do
      if ((i > 0 && (i % 2 == 0))); then
        if [[ -n "${BASH_REMATCH[i]}" ]]; then
          [[ -n "$PATT" ]] && PATT="$PATT|"
          PATT="$PATT${BASH_REMATCH[i]}"
        fi
      fi
    done
    #echo "... $PATT"
    [[ -n "$PATT" ]] && { grep -vE "$PATT" "$LOGB" >"$TMPF" ; cp "$TMPF" "$LOGB" ; }
  else
    PATT=$( $SED -E 's/^\[[0-9a-f]{10}\]( . )?(.+)$/\2/' <<<"$line" )
    [[ -n "$PATT" ]] && { grep -v "$PATT" "$LOGB" >"$TMPF" ; cp "$TMPF" "$LOGB" ; }
  fi
done

# Convert remaining commits into git commands

echo -e "#!/usr/bin/env bash\nset -e\ngit checkout ${DEST}\n" >"$TMPF"
cat "$LOGB" | while read line; do
  if [[ $line =~ ^\[([0-9a-f]{10})\]\ *(.*)$ ]]; then
    CID=${BASH_REMATCH[1]}
    REST=${BASH_REMATCH[2]}
    echo "git cherry-pick $CID ;# $REST" >>"$TMPF"
  else
    echo ";# $line" >>"$TMPF"
  fi
done
mv "$TMPF" "$SCRF"
chmod +x "$SCRF"

((DRYRUN)) && rm -r "$TMPDIR" || open "$TMPDIR"