#!/bin/sh
#
# Copyright (c) 2005, 2006 Junio C Hamano

USAGE='[--signoff] [--dotest=<dir>] [--keep] [--utf8 | --no-utf8]
  [--3way] [--interactive] [--binary]
  [--whitespace=<option>] [-C<n>] [-p<n>]
  <mbox>|<Maildir>...
  or, when resuming [--skip | --resolved]'
. git-sh-setup
set_reflog_action am
require_work_tree

git var GIT_COMMITTER_IDENT >/dev/null || exit

stop_here () {
    echo "$1" >"$dotest/next"
    exit 1
}

stop_here_user_resolve () {
    if [ -n "$resolvemsg" ]; then
            printf '%s\n' "$resolvemsg"
            stop_here $1
    fi
    cmdline=$(basename $0)
    if test '' != "$interactive"
    then
        cmdline="$cmdline -i"
    fi
    if test '' != "$threeway"
    then
        cmdline="$cmdline -3"
    fi
    if test '.dotest' != "$dotest"
    then
        cmdline="$cmdline -d=$dotest"
    fi
    echo "When you have resolved this problem run \"$cmdline --resolved\"."
    echo "If you would prefer to skip this patch, instead run \"$cmdline --skip\"."

    stop_here $1
}

go_next () {
        rm -f "$dotest/$msgnum" "$dotest/msg" "$dotest/msg-clean" \
                "$dotest/patch" "$dotest/info"
        echo "$next" >"$dotest/next"
        this=$next
}

cannot_fallback () {
        echo "$1"
        echo "Cannot fall back to three-way merge."
        exit 1
}

fall_back_3way () {
    O_OBJECT=`cd "$GIT_OBJECT_DIRECTORY" && pwd`

    rm -fr "$dotest"/patch-merge-*
    mkdir "$dotest/patch-merge-tmp-dir"

    # First see if the patch records the index info that we can use.
    git apply --build-fake-ancestor "$dotest/patch-merge-tmp-index" \
        "$dotest/patch" &&
    GIT_INDEX_FILE="$dotest/patch-merge-tmp-index" \
    git write-tree >"$dotest/patch-merge-base+" ||
    cannot_fallback "Repository lacks necessary blobs to fall back on 3-way merge."

    echo Using index info to reconstruct a base tree...
    if GIT_INDEX_FILE="$dotest/patch-merge-tmp-index" \
        git apply $binary --cached <"$dotest/patch"
    then
        mv "$dotest/patch-merge-base+" "$dotest/patch-merge-base"
        mv "$dotest/patch-merge-tmp-index" "$dotest/patch-merge-index"
    else
        cannot_fallback "Did you hand edit your patch?
It does not apply to blobs recorded in its index."
    fi

    test -f "$dotest/patch-merge-index" &&
    his_tree=$(GIT_INDEX_FILE="$dotest/patch-merge-index" git write-tree) &&
    orig_tree=$(cat "$dotest/patch-merge-base") &&
    rm -fr "$dotest"/patch-merge-* || exit 1

    echo Falling back to patching base and 3-way merge...

    # This is not so wrong.  Depending on which base we picked,
    # orig_tree may be wildly different from ours, but his_tree
    # has the same set of wildly different changes in parts the
    # patch did not touch, so recursive ends up canceling them,
    # saying that we reverted all those changes.

    eval GITHEAD_$his_tree='"$SUBJECT"'
    export GITHEAD_$his_tree
    git-merge-recursive $orig_tree -- HEAD $his_tree || {
            git rerere
            echo Failed to merge in the changes.
            exit 1
    }
    unset GITHEAD_$his_tree
}

reread_subject () {
        git stripspace <"$1" | sed -e 1q
}

prec=4
dotest=.dotest sign= utf8=t keep= skip= interactive= resolved= binary=
resolvemsg= resume=
git_apply_opt=

while test $# != 0
do
        case "$1" in
        -d=*|--d=*|--do=*|--dot=*|--dote=*|--dotes=*|--dotest=*)
        dotest=`expr "z$1" : 'z-[^=]*=\(.*\)'`; shift ;;
        -d|--d|--do|--dot|--dote|--dotes|--dotest)
        case "$#" in 1) usage ;; esac; shift
        dotest="$1"; shift;;

        -i|--i|--in|--int|--inte|--inter|--intera|--interac|--interact|\
        --interacti|--interactiv|--interactive)
        interactive=t; shift ;;

        -b|--b|--bi|--bin|--bina|--binar|--binary)
        binary=t; shift ;;

        -3|--3|--3w|--3wa|--3way)
        threeway=t; shift ;;
        -s|--s|--si|--sig|--sign|--signo|--signof|--signoff)
        sign=t; shift ;;
        -u|--u|--ut|--utf|--utf8)
        utf8=t; shift ;; # this is now default
        --no-u|--no-ut|--no-utf|--no-utf8)
        utf8=; shift ;;
        -k|--k|--ke|--kee|--keep)
        keep=t; shift ;;

        -r|--r|--re|--res|--reso|--resol|--resolv|--resolve|--resolved)
        resolved=t; shift ;;

        --sk|--ski|--skip)
        skip=t; shift ;;

        --whitespace=*|-C*|-p*)
        git_apply_opt="$git_apply_opt $1"; shift ;;

        --resolvemsg=*)
        resolvemsg=${1#--resolvemsg=}; shift ;;

        --)
        shift; break ;;
        -*)
        usage ;;
        *)
        break ;;
        esac
done

# If the dotest directory exists, but we have finished applying all the
# patches in them, clear it out.
if test -d "$dotest" &&
   last=$(cat "$dotest/last") &&
   next=$(cat "$dotest/next") &&
   test $# != 0 &&
   test "$next" -gt "$last"
then
   rm -fr "$dotest"
fi

if test -d "$dotest"
then
        case "$#,$skip$resolved" in
        0,*t*)
                # Explicit resume command and we do not have file, so
                # we are happy.
                : ;;
        0,)
                # No file input but without resume parameters; catch
                # user error to feed us a patch from standard input
                # when there is already .dotest.  This is somewhat
                # unreliable -- stdin could be /dev/null for example
                # and the caller did not intend to feed us a patch but
                # wanted to continue unattended.
                tty -s
                ;;
        *)
                false
                ;;
        esac ||
        die "previous dotest directory $dotest still exists but mbox given."
        resume=yes
else
        # Make sure we are not given --skip nor --resolved
        test ",$skip,$resolved," = ,,, ||
                die "Resolve operation not in progress, we are not resuming."

        # Start afresh.
        mkdir -p "$dotest" || exit

        git mailsplit -d"$prec" -o"$dotest" -b -- "$@" > "$dotest/last" ||  {
                rm -fr "$dotest"
                exit 1
        }

        # -b, -s, -u, -k and --whitespace flags are kept for the
        # resuming session after a patch failure.
        # -3 and -i can and must be given when resuming.
        echo "$binary" >"$dotest/binary"
        echo " $ws" >"$dotest/whitespace"
        echo "$sign" >"$dotest/sign"
        echo "$utf8" >"$dotest/utf8"
        echo "$keep" >"$dotest/keep"
        echo 1 >"$dotest/next"
fi

case "$resolved" in
'')
        files=$(git diff-index --cached --name-only HEAD --) || exit
        if [ "$files" ]; then
           echo "Dirty index: cannot apply patches (dirty: $files)" >&2
           exit 1
        fi
esac

if test "$(cat "$dotest/binary")" = t
then
        binary=--allow-binary-replacement
fi
if test "$(cat "$dotest/utf8")" = t
then
        utf8=-u
else
        utf8=-n
fi
if test "$(cat "$dotest/keep")" = t
then
        keep=-k
fi
ws=`cat "$dotest/whitespace"`
if test "$(cat "$dotest/sign")" = t
then
        SIGNOFF=`git-var GIT_COMMITTER_IDENT | sed -e '
                        s/>.*/>/
                        s/^/Signed-off-by: /'
                `
else
        SIGNOFF=
fi

last=`cat "$dotest/last"`
this=`cat "$dotest/next"`
if test "$skip" = t
then
        git rerere clear
        this=`expr "$this" + 1`
        resume=
fi

if test "$this" -gt "$last"
then
        echo Nothing to do.
        rm -fr "$dotest"
        exit
fi

while test "$this" -le "$last"
do
        msgnum=`printf "%0${prec}d" $this`
        next=`expr "$this" + 1`
        test -f "$dotest/$msgnum" || {
                resume=
                go_next
                continue
        }

        # If we are not resuming, parse and extract the patch information
        # into separate files:
        #  - info records the authorship and title
        #  - msg is the rest of commit log message
        #  - patch is the patch body.
        #
        # When we are resuming, these files are either already prepared
        # by the user, or the user can tell us to do so by --resolved flag.
        case "$resume" in
        '')
                git mailinfo $keep $utf8 "$dotest/msg" "$dotest/patch" \
                        <"$dotest/$msgnum" >"$dotest/info" ||
                        stop_here $this

                # skip pine's internal folder data
                grep '^Author: Mail System Internal Data$' \
                        <"$dotest"/info >/dev/null &&
                        go_next && continue

                test -s $dotest/patch || {
                        echo "Patch is empty.  Was it split wrong?"
                        stop_here $this
                }
                git stripspace < "$dotest/msg" > "$dotest/msg-clean"
                ;;
        esac

        GIT_AUTHOR_NAME="$(sed -n '/^Author/ s/Author: //p' "$dotest/info")"
        GIT_AUTHOR_EMAIL="$(sed -n '/^Email/ s/Email: //p' "$dotest/info")"
        GIT_AUTHOR_DATE="$(sed -n '/^Date/ s/Date: //p' "$dotest/info")"

        if test -z "$GIT_AUTHOR_EMAIL"
        then
                echo "Patch does not have a valid e-mail address."
                stop_here $this
        fi

        export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE

        SUBJECT="$(sed -n '/^Subject/ s/Subject: //p' "$dotest/info")"
        case "$keep_subject" in -k)  SUBJECT="[PATCH] $SUBJECT" ;; esac

        case "$resume" in
        '')
            if test '' != "$SIGNOFF"
            then
                LAST_SIGNED_OFF_BY=`
                    sed -ne '/^Signed-off-by: /p' \
                    "$dotest/msg-clean" |
                    tail -n 1
                `
                ADD_SIGNOFF=`
                    test "$LAST_SIGNED_OFF_BY" = "$SIGNOFF" || {
                    test '' = "$LAST_SIGNED_OFF_BY" && echo
                    echo "$SIGNOFF"
                }`
            else
                ADD_SIGNOFF=
            fi
            {
                printf '%s\n' "$SUBJECT"
                if test -s "$dotest/msg-clean"
                then
                        echo
                        cat "$dotest/msg-clean"
                fi
                if test '' != "$ADD_SIGNOFF"
                then
                        echo "$ADD_SIGNOFF"
                fi
            } >"$dotest/final-commit"
            ;;
        *)
                case "$resolved$interactive" in
                tt)
                        # This is used only for interactive view option.
                        git diff-index -p --cached HEAD -- >"$dotest/patch"
                        ;;
                esac
        esac

        resume=
        if test "$interactive" = t
        then
            test -t 0 ||
            die "cannot be interactive without stdin connected to a terminal."
            action=again
            while test "$action" = again
            do
                echo "Commit Body is:"
                echo "--------------------------"
                cat "$dotest/final-commit"
                echo "--------------------------"
                printf "Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all "
                read reply
                case "$reply" in
                [yY]*) action=yes ;;
                [aA]*) action=yes interactive= ;;
                [nN]*) action=skip ;;
                [eE]*) git_editor "$dotest/final-commit"
                       SUBJECT=$(reread_subject "$dotest/final-commit")
                       action=again ;;
                [vV]*) action=again
                       LESS=-S ${PAGER:-less} "$dotest/patch" ;;
                *)     action=again ;;
                esac
            done
        else
            action=yes
        fi

        if test $action = skip
        then
                go_next
                continue
        fi

        if test -x "$GIT_DIR"/hooks/applypatch-msg
        then
                "$GIT_DIR"/hooks/applypatch-msg "$dotest/final-commit" ||
                stop_here $this
        fi

        echo
        printf 'Applying %s\n' "$SUBJECT"
        echo

        case "$resolved" in
        '')
                git apply $git_apply_opt $binary --index "$dotest/patch"
                apply_status=$?
                ;;
        t)
                # Resolved means the user did all the hard work, and
                # we do not have to do any patch application.  Just
                # trust what the user has in the index file and the
                # working tree.
                resolved=
                git diff-index --quiet --cached HEAD -- && {
                        echo "No changes - did you forget to use 'git add'?"
                        stop_here_user_resolve $this
                }
                unmerged=$(git ls-files -u)
                if test -n "$unmerged"
                then
                        echo "You still have unmerged paths in your index"
                        echo "did you forget to use 'git add'?"
                        stop_here_user_resolve $this
                fi
                apply_status=0
                git rerere
                ;;
        esac

        if test $apply_status = 1 && test "$threeway" = t
        then
                if (fall_back_3way)
                then
                    # Applying the patch to an earlier tree and merging the
                    # result may have produced the same tree as ours.
                    git diff-index --quiet --cached HEAD -- && {
                        echo No changes -- Patch already applied.
                        go_next
                        continue
                    }
                    # clear apply_status -- we have successfully merged.
                    apply_status=0
                fi
        fi
        if test $apply_status != 0
        then
                echo Patch failed at $msgnum.
                stop_here_user_resolve $this
        fi

        if test -x "$GIT_DIR"/hooks/pre-applypatch
        then
                "$GIT_DIR"/hooks/pre-applypatch || stop_here $this
        fi

        tree=$(git write-tree) &&
        echo Wrote tree $tree &&
        parent=$(git rev-parse --verify HEAD) &&
        commit=$(git commit-tree $tree -p $parent <"$dotest/final-commit") &&
        echo Committed: $commit &&
        git update-ref -m "$GIT_REFLOG_ACTION: $SUBJECT" HEAD $commit $parent ||
        stop_here $this

        if test -x "$GIT_DIR"/hooks/post-applypatch
        then
                "$GIT_DIR"/hooks/post-applypatch
        fi

        go_next
done

rm -fr "$dotest"