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

SUBDIRECTORY_OK=Yes
OPTIONS_KEEPDASHDASH=
OPTIONS_SPEC="\
git am [options] [<mbox>|<Maildir>...]
git am [options] (--resolved | --skip | --abort)
--
i,interactive   run interactively
b,binary*       (historical option -- no-op)
3,3way          allow fall back on 3way merging if needed
q,quiet         be quiet
s,signoff       add a Signed-off-by line to the commit message
u,utf8          recode into utf8 (default)
k,keep          pass -k flag to git-mailinfo
whitespace=     pass it through git-apply
directory=      pass it through git-apply
C=              pass it through git-apply
p=              pass it through git-apply
patch-format=   format the patch(es) are in
reject          pass it through git-apply
resolvemsg=     override error message when patch failure occurs
r,resolved      to be used after a patch failure
skip            skip the current patch
abort           restore the original branch and abort the patching operation.
committer-date-is-author-date    lie about committer date
ignore-date     use current timestamp for author date
rebasing*       (internal use for git-rebase)"

. git-sh-setup
prefix=$(git rev-parse --show-prefix)
set_reflog_action am
require_work_tree
cd_to_toplevel

git var GIT_COMMITTER_IDENT >/dev/null ||
        die "You need to set your committer info first"

if git rev-parse --verify -q HEAD >/dev/null
then
        HAS_HEAD=yes
else
        HAS_HEAD=
fi

sq () {
        git rev-parse --sq-quote "$@"
}

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

stop_here_user_resolve () {
    if [ -n "$resolvemsg" ]; then
            printf '%s\n' "$resolvemsg"
            stop_here $1
    fi
    cmdline="git am"
    if test '' != "$interactive"
    then
        cmdline="$cmdline -i"
    fi
    if test '' != "$threeway"
    then
        cmdline="$cmdline -3"
    fi
    echo "When you have resolved this problem run \"$cmdline --resolved\"."
    echo "If you would prefer to skip this patch, instead run \"$cmdline --skip\"."
    echo "To restore the original branch and stop patching run \"$cmdline --abort\"."

    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."

    say Using index info to reconstruct a base tree...
    if GIT_INDEX_FILE="$dotest/patch-merge-tmp-index" \
        git apply --cached <"$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

    say 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_$his_tree='"$FIRSTLINE"'
    export GITHEAD_$his_tree
    if test -n "$GIT_QUIET"
    then
            export GIT_MERGE_VERBOSITY=0
    fi
    git-merge-recursive $orig_tree -- HEAD $his_tree || {
            git rerere
            echo Failed to merge in the changes.
            exit 1
    }
    unset GITHEAD_$his_tree
}

clean_abort () {
        test $# = 0 || echo >&2 "$@"
        rm -fr "$dotest"
        exit 1
}

patch_format=

check_patch_format () {
        # early return if patch_format was set from the command line
        if test -n "$patch_format"
        then
                return 0
        fi

        # we default to mbox format if input is from stdin and for
        # directories
        if test $# = 0 || test "x$1" = "x-" || test -d "$1"
        then
                patch_format=mbox
                return 0
        fi

        # otherwise, check the first few lines of the first patch to try
        # to detect its format
        {
                read l1
                read l2
                read l3
                case "$l1" in
                "From "* | "From: "*)
                        patch_format=mbox
                        ;;
                '# This series applies on GIT commit'*)
                        patch_format=stgit-series
                        ;;
                "# HG changeset patch")
                        patch_format=hg
                        ;;
                *)
                        # if the second line is empty and the third is
                        # a From, Author or Date entry, this is very
                        # likely an StGIT patch
                        case "$l2,$l3" in
                        ,"From: "* | ,"Author: "* | ,"Date: "*)
                                patch_format=stgit
                                ;;
                        *)
                                ;;
                        esac
                        ;;
                esac
                if test -z "$patch_format" &&
                        test -n "$l1" &&
                        test -n "$l2" &&
                        test -n "$l3"
                then
                        # This begins with three non-empty lines.  Is this a
                        # piece of e-mail a-la RFC2822?  Grab all the headers,
                        # discarding the indented remainder of folded lines,
                        # and see if it looks like that they all begin with the
                        # header field names...
                        sed -n -e '/^$/q' -e '/^[       ]/d' -e p "$1" |
                        egrep -v '^[A-Za-z]+(-[A-Za-z]+)*:' >/dev/null ||
                        patch_format=mbox
                fi
        } < "$1" || clean_abort
}

split_patches () {
        case "$patch_format" in
        mbox)
                git mailsplit -d"$prec" -o"$dotest" -b -- "$@" > "$dotest/last" ||
                clean_abort
                ;;
        stgit-series)
                if test $# -ne 1
                then
                        clean_abort "Only one StGIT patch series can be applied at once"
                fi
                series_dir=`dirname "$1"`
                series_file="$1"
                shift
                {
                        set x
                        while read filename
                        do
                                set "$@" "$series_dir/$filename"
                        done
                        # remove the safety x
                        shift
                        # remove the arg coming from the first-line comment
                        shift
                } < "$series_file" || clean_abort
                # set the patch format appropriately
                patch_format=stgit
                # now handle the actual StGIT patches
                split_patches "$@"
                ;;
        stgit)
                this=0
                for stgit in "$@"
                do
                        this=`expr "$this" + 1`
                        msgnum=`printf "%0${prec}d" $this`
                        # Perl version of StGIT parse_patch. The first nonemptyline
                        # not starting with Author, From or Date is the
                        # subject, and the body starts with the next nonempty
                        # line not starting with Author, From or Date
                        perl -ne 'BEGIN { $subject = 0 }
                                if ($subject > 1) { print ; }
                                elsif (/^\s+$/) { next ; }
                                elsif (/^Author:/) { print s/Author/From/ ; }
                                elsif (/^(From|Date)/) { print ; }
                                elsif ($subject) {
                                        $subject = 2 ;
                                        print "\n" ;
                                        print ;
                                } else {
                                        print "Subject: ", $_ ;
                                        $subject = 1;
                                }
                        ' < "$stgit" > "$dotest/$msgnum" || clean_abort
                done
                echo "$this" > "$dotest/last"
                this=
                msgnum=
                ;;
        *)
                clean_abort "Patch format $patch_format is not supported."
                ;;
        esac
}

prec=4
dotest="$GIT_DIR/rebase-apply"
sign= utf8=t keep= skip= interactive= resolved= rebasing= abort=
resolvemsg= resume=
git_apply_opt=
committer_date_is_author_date=
ignore_date=

while test $# != 0
do
        case "$1" in
        -i|--interactive)
                interactive=t ;;
        -b|--binary)
                : ;;
        -3|--3way)
                threeway=t ;;
        -s|--signoff)
                sign=t ;;
        -u|--utf8)
                utf8=t ;; # this is now default
        --no-utf8)
                utf8= ;;
        -k|--keep)
                keep=t ;;
        -r|--resolved)
                resolved=t ;;
        --skip)
                skip=t ;;
        --abort)
                abort=t ;;
        --rebasing)
                rebasing=t threeway=t keep=t ;;
        -d|--dotest)
                die "-d option is no longer supported.  Do not use."
                ;;
        --resolvemsg)
                shift; resolvemsg=$1 ;;
        --whitespace|--directory)
                git_apply_opt="$git_apply_opt $(sq "$1=$2")"; shift ;;
        -C|-p)
                git_apply_opt="$git_apply_opt $(sq "$1$2")"; shift ;;
        --patch-format)
                shift ; patch_format="$1" ;;
        --reject)
                git_apply_opt="$git_apply_opt $1" ;;
        --committer-date-is-author-date)
                committer_date_is_author_date=t ;;
        --ignore-date)
                ignore_date=t ;;
        -q|--quiet)
                GIT_QUIET=t ;;
        --)
                shift; break ;;
        *)
                usage ;;
        esac
        shift
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$abort" 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.
                test -t 0
                ;;
        *)
                false
                ;;
        esac ||
        die "previous rebase directory $dotest still exists but mbox given."
        resume=yes

        case "$skip,$abort" in
        t,t)
                die "Please make up your mind. --skip or --abort?"
                ;;
        t,)
                git rerere clear
                git read-tree --reset -u HEAD HEAD
                orig_head=$(cat "$GIT_DIR/ORIG_HEAD")
                git reset HEAD
                git update-ref ORIG_HEAD $orig_head
                ;;
        ,t)
                if test -f "$dotest/rebasing"
                then
                        exec git rebase --abort
                fi
                git rerere clear
                test -f "$dotest/dirtyindex" || {
                        git read-tree --reset -u HEAD ORIG_HEAD
                        git reset ORIG_HEAD
                }
                rm -fr "$dotest"
                exit ;;
        esac
        rm -f "$dotest/dirtyindex"
else
        # Make sure we are not given --skip, --resolved, nor --abort
        test "$skip$resolved$abort" = "" ||
                die "Resolve operation not in progress, we are not resuming."

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

        if test -n "$prefix" && test $# != 0
        then
                first=t
                for arg
                do
                        test -n "$first" && {
                                set x
                                first=
                        }
                        case "$arg" in
                        /*)
                                set "$@" "$arg" ;;
                        *)
                                set "$@" "$prefix$arg" ;;
                        esac
                done
                shift
        fi

        check_patch_format "$@"

        split_patches "$@"

        # -s, -u, -k, --whitespace, -3, -C, -q and -p flags are kept
        # for the resuming session after a patch failure.
        # -i can and must be given when resuming.
        echo " $git_apply_opt" >"$dotest/apply-opt"
        echo "$threeway" >"$dotest/threeway"
        echo "$sign" >"$dotest/sign"
        echo "$utf8" >"$dotest/utf8"
        echo "$keep" >"$dotest/keep"
        echo "$GIT_QUIET" >"$dotest/quiet"
        echo 1 >"$dotest/next"
        if test -n "$rebasing"
        then
                : >"$dotest/rebasing"
        else
                : >"$dotest/applying"
                if test -n "$HAS_HEAD"
                then
                        git update-ref ORIG_HEAD HEAD
                else
                        git update-ref -d ORIG_HEAD >/dev/null 2>&1
                fi
        fi
fi

case "$resolved" in
'')
        case "$HAS_HEAD" in
        '')
                files=$(git ls-files) ;;
        ?*)
                files=$(git diff-index --cached --name-only HEAD --) ;;
        esac || exit
        if test "$files"
        then
                test -n "$HAS_HEAD" && : >"$dotest/dirtyindex"
                die "Dirty index: cannot apply patches (dirty: $files)"
        fi
esac

if test "$(cat "$dotest/utf8")" = t
then
        utf8=-u
else
        utf8=-n
fi
if test "$(cat "$dotest/keep")" = t
then
        keep=-k
fi
if test "$(cat "$dotest/quiet")" = t
then
        GIT_QUIET=t
fi
if test "$(cat "$dotest/threeway")" = t
then
        threeway=t
fi
git_apply_opt=$(cat "$dotest/apply-opt")
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 "$skip" = t
then
        this=`expr "$this" + 1`
        resume=
fi

if test "$this" -gt "$last"
then
        say 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 $this
                }
                if test -f "$dotest/rebasing" &&
                        commit=$(sed -e 's/^From \([0-9a-f]*\) .*/\1/' \
                                -e q "$dotest/$msgnum") &&
                        test "$(git cat-file -t "$commit")" = commit
                then
                        git cat-file commit "$commit" |
                        sed -e '1,/^$/d' >"$dotest/msg-clean"
                else
                        SUBJECT="$(sed -n '/^Subject/ s/Subject: //p' "$dotest/info")"
                        case "$keep_subject" in -k)  SUBJECT="[PATCH] $SUBJECT" ;; esac

                        (printf '%s\n\n' "$SUBJECT"; cat "$dotest/msg") |
                                git stripspace > "$dotest/msg-clean"
                fi
                ;;
        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

        case "$resume" in
        '')
            if test '' != "$SIGNOFF"
            then
                LAST_SIGNED_OFF_BY=`
                    sed -ne '/^Signed-off-by: /p' \
                    "$dotest/msg-clean" |
                    sed -ne '$p'
                `
                ADD_SIGNOFF=`
                    test "$LAST_SIGNED_OFF_BY" = "$SIGNOFF" || {
                    test '' = "$LAST_SIGNED_OFF_BY" && echo
                    echo "$SIGNOFF"
                }`
            else
                ADD_SIGNOFF=
            fi
            {
                if test -s "$dotest/msg-clean"
                then
                        cat "$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"
                       action=again ;;
                [vV]*) action=again
                       LESS=-S ${PAGER:-less} "$dotest/patch" ;;
                *)     action=again ;;
                esac
            done
        else
            action=yes
        fi
        FIRSTLINE=$(sed 1q "$dotest/final-commit")

        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

        say "Applying: $FIRSTLINE"

        case "$resolved" in
        '')
                # When we are allowed to fall back to 3-way later, don't give
                # false errors during the initial attempt.
                squelch=
                if test "$threeway" = t
                then
                        squelch='>/dev/null 2>&1 '
                fi
                eval "git apply $squelch$git_apply_opt"' --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 -- && {
                        say No changes -- Patch already applied.
                        go_next
                        continue
                    }
                    # clear apply_status -- we have successfully merged.
                    apply_status=0
                fi
        fi
        if test $apply_status != 0
        then
                printf 'Patch failed at %s %s\n' "$msgnum" "$FIRSTLINE"
                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=$(git write-tree) &&
        commit=$(
                if test -n "$ignore_date"
                then
                        GIT_AUTHOR_DATE=
                fi
                parent=$(git rev-parse --verify -q HEAD) ||
                say >&2 "applying to an empty history"

                if test -n "$committer_date_is_author_date"
                then
                        GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"
                        export GIT_COMMITTER_DATE
                fi &&
                git commit-tree $tree ${parent:+-p} $parent <"$dotest/final-commit"
        ) &&
        git update-ref -m "$GIT_REFLOG_ACTION: $FIRSTLINE" HEAD $commit $parent ||
        stop_here $this

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

        go_next
done

git gc --auto

rm -fr "$dotest"