#! /bin/sh
# tla-pure-merge: apply un-merged patches on one branch to another
# Copyright (C) Cameron Patrick, 2005.
#
#  Permission is hereby granted, free of charge, to any person obtaining a copy
#  of this software and associated documentation files (the "Software"), to
#  deal in the Software without restriction, including without limitation the
#  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
#  sell copies of the Software, and to permit persons to whom the Software is
#  furnished to do so, subject to the following conditions:
# 
#  The above copyright notice and this permission notice shall be included in
#  all copies or substantial portions of the Software.
# 
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
#  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
#  IN THE SOFTWARE.
#
# TODO: should allow applying patches to existing project tree

set -e

usage()
{
    echo "usage: tla-pure-merge [options] SOURCE DESTINATION"
    echo "Replays pure changesets from the SOURCE version or revision to"
    echo "the DESTINATION version."
    echo
    echo "Options:"
    echo "  -h          --help                Display this message"
    echo "  -a          --all                 Merge all patches without asking"
    echo "* -i          --interactive         Ask which patches to merge"
    echo "  -p PATCH    --patches PATCH       Merge the listed patches"
    echo "  -l          --pull                Use current tree version as DESTINATION"
    echo "  -s          --push                Use current tree version as SOURCE"
    echo "              --edit-summary        Add source revision to summary"
    echo "*             --no-edit-summary     Use the same log summaries as the source"
    echo "*             --skip-present        Use tla missing --skip-present"
    echo "              --no-skip-present     Disable the --skip-present behaviour"
    echo
    echo "Options indicated with a * are on by default."
    echo
    echo "If --pull or --push is specified, and no revision name is given, tla-pure-merge"
    echo "will use use {arch}/+upstream-version as the SOURCE or DESTINATION."
    exit 0
}

die()
{
    echo "$@" 1>&2
    echo "Try tla-pure-merge --help for command-line options." 1>&2
    exit 1
}

find_upstream_vers()
{
    local tree_root="$(tla tree-root)"
    if [ -f "${tree_root}/{arch}/+upstream-version" ]; then
        upstream_vers="$(cat ${tree_root}/{arch}/+upstream-version)"
    else
        upstream_vers=""
    fi
}

clean_up()
{
    cd ..
    rm -rf $temp_dir
}

if [ "$PAGER" = "" ]; then
    PAGER=less
fi

edit_summary=no
skip_present=yes
interactive=yes
mode=normal
patches_missing=""
source_vers=""
dest_vers=""

# parse command line arguments
while [ "$#" != "0" ]; do
    case "$1" in
        -h|--help)
            usage
            ;;
        -a|--all)
            interactive=no
            ;;
        -i|--interace)
            interactive=yes
            ;;
        -p|--patches)
            if [ "$2" = "" ]; then
                die "--patches specified but no patch list given"
            fi
            patches_missing="$2"
            interactive=no
            echo "* patches to merge: $2"
            shift
            ;;
        -l|--pull)
            mode=pull
            if ! tla tree-root >/dev/null; then
                die "--pull given but not in a project tree."
            fi
            dest_vers="$(tla tree-version)"
            find_upstream_vers
            echo "* using tree version ${dest_vers} as destination"
            ;;
        -s|--push)
            mode=push
            if ! tla tree-root >/dev/null; then
                die "--push given but not in a project tree."
            fi
            find_upstream_vers
            source_vers="$(tla tree-version)"
            echo "* using tree version ${source_vers} as source"
            ;;
        --edit-summary)
            edit_summary=yes
            ;;
        --no-edit-summary)
            edit_summary=no
            ;;
        --skip-present)
            skip_present=yes
            ;;
        --no-skip-present)
            skip_present=no
            ;;
        -*)
            die "Unknown option argument $1"
            ;;
        *)
            if [ "$source_vers" = "" ]; then
                source_vers="$1"
            elif [ "$dest_vers" = "" ]; then
                dest_vers="$1"
            else
                die "Don't know what to do with argument $1"
            fi
            ;;
    esac
    shift
done

# default to upstream versions if possible
if [ "$mode" = "pull" ] &&
   [ "$source_vers" = "" ] &&
   [ "$upstream_vers" != "" ]; then
    echo "* using upstream version ${upstream_vers} as source"
    source_vers="$upstream_vers"
fi

if [ "$mode" = "push" ] &&
   [ "$dest_vers" = "" ] &&
   [ "$upstream_vers" != "" ]; then
    echo "* using upstream version ${upstream_vers} as destination"
    dest_vers="$upstream_vers"
fi

# make sure we have a source and a destination
if [ "$source_vers" = "" ]; then
    die "No source version specified to merge from."
fi

if [ "$dest_vers" = "" ]; then
    die "No destination version specified to merge into."
fi

# grab a copy of the destination revision
temp_dir=",,pure-merge-$$-$(tla parse-package-name --non-arch $dest_vers)"
tla get --silent $dest_vers $temp_dir
cd $temp_dir
trap "clean_up; exit 1" INT EXIT

# decide which patches to consider merging
if [ "$patches_missing" != "" ]; then
    :
elif tla parse-package-name -l $source_vers >/dev/null 2>/dev/null; then
    patches_missing="$(tla parse-package-name -l $source_vers)"
else
    skip_present_flag=--skip-present
    [ $skip_present = no ] && skip_present_flag=''
    patches_missing="$(tla missing $skip_present_flag $source_vers | grep -v ^base- || true)"
fi
source_vers="$(tla parse-package-name -a $source_vers)/$(tla parse-package-name --package-version $source_vers)"

# maybe there are no missing patches?
if [ "$patches_missing" = "" ]; then
    echo
    echo "No changes to merge."
    exit 0
fi

# fetch patches and log entries
for x in $patches_missing; do
    patch="$source_vers--$x"
    echo "* fetching patch $patch"
    tla get-changeset $patch ,tmp-cset-$x
    tla cat-archive-log $patch >,tmp-log-$x
done

# decide which patches to merge
if [ "$interactive" = "no" ]; then
    act="a"
else
    act="?"
fi
patches_to_merge=""
for x in $patches_missing; do
    summary="$(grep '^Summary: ' ,tmp-log-$x | sed 's/^Summary: //g')"
    creator="$(grep '^Creator: ' ,tmp-log-$x | sed 's/^Creator: //g')"
    date="$(grep '^Date: ' ,tmp-log-$x | sed 's/^Date: //g')"
    echo
    echo "$x"
    echo "    $date    $creator"
    echo "    $summary"
    while true; do
        if [ "$act" = "a" ] || [ "$act" = "d" ]; then
            break
        fi
        echo -n "Merge this patch? [ynvxdaq?] "
        read act
        case $act in
            y|Y|n|N|d|D|a|A)
                break
                ;;
            v|V)
                tla show-changeset --diffs ,tmp-cset-$x | $PAGER
                ;;
            x|X)
                tla show-changeset ,tmp-cset-$x
                ;;
            q|Q)
                echo "Cancelling merge."
                exit 0
                ;;
            *)
                echo "Your choices are:"
                echo "  y - merge this patch"
                echo "  n - don't merge this patch"
                echo "  v - view this patch and ask again"
                echo "  x - view a summary of this patch and ask again"
                echo "  d - skip this patch and all after it"
                echo "  a - merge this patch and all after it"
                echo "  q - cancel, don't merge anything"
                echo
                ;;
        esac
    done
    if [ "$act" = "y" ] || [ "$act" = "a" ]; then
        patches_to_merge="$patches_to_merge $x"
    fi
done
echo

# merge selected patches
for x in $patches_to_merge; do
    patch="$source_vers--$x"

    if ! tla changes -q; then
        echo "PANIC: Gah, changes have been made to source tree."
        echo "This shouldn't happen :("
        # remove trap now, we don't want to remove the temp dir
        trap - EXIT
        exit 2
    fi

    rm -rf ,tmp-log
    cp ,tmp-log-$x ,tmp-log
    
    echo "* pure merge: applying $patch"
    log_file="$(tla make-log)"

    merge_of="$patch"
    merge_of_pure=no
    if grep -q '^Pure-merge-of: ' ,tmp-log; then
        merge_of="$(sed -n -e '/^Pure-merge-of: / { s/^Pure-merge-of: \(.*\)/\1/g; p }' ,tmp-log)"
        merge_of_pure=yes
    fi

    cat /dev/null >$log_file
    if [ "$merge_of_pure" = "yes" ]; then
        cat ,tmp-log | \
            sed -n -e '/^Original-/ p' -e '/^Summary: / Q' >>$log_file
    else
        cat ,tmp-log | \
            sed -e 's/^\(Creator\|Date\|Standard-date\): /Original-\1: /g' \
                -e t -e d -e '/^Summary: / Q' \
            >>$log_file
    fi
    echo "Direct-ancestor: $patch" >>$log_file
    echo "Pure-merge-of: $merge_of" >>$log_file
    if [ "$edit_summary" = "yes" ]; then
        cat ,tmp-log | sed -n \
            -e '/^Summary: / { s/ [merge of .*]$//g; s%$% [merge of '"$merge_of"']%g; p; q }' >>$log_file
    else
        cat ,tmp-log | sed -n \
            -e '/^Summary: / { p; q }' >>$log_file
    fi
    cat ,tmp-log | sed -e '1,/^Summary: / d' >>$log_file
    rm -f ,tmp-log

    if ! tla apply-changeset ,tmp-cset-$x .; then
        echo "* conflicts during pure merge of $patch"
        echo "Please fix conflicts by hand and run \`tla commit\`"
        echo "in directory $temp_dir"
        # remove trap now, we don't want to remove the temp dir
        trap - EXIT
        exit 1
    fi

    tla commit
done

exit 0

# arch-tag: a36bd7cf-88b4-4ef9-9d6f-944d18ac6600