#!/bin/sh
# Copyright (c) 2007, Nanako Shiraishi

dashless=$(basename "$0" | sed -e 's/-/ /')
USAGE="list [<options>]
   or: $dashless show [<stash>]
   or: $dashless drop [-q|--quiet] [<stash>]
   or: $dashless ( pop | apply ) [--index] [-q|--quiet] [<stash>]
   or: $dashless branch <branchname> [<stash>]
   or: $dashless [save [--patch] [-k|--[no-]keep-index] [-q|--quiet]
                       [-u|--include-untracked] [-a|--all] [<message>]]
   or: $dashless clear"

SUBDIRECTORY_OK=Yes
OPTIONS_SPEC=
START_DIR=$(pwd)
. git-sh-setup
require_work_tree
cd_to_toplevel

TMP="$GIT_DIR/.git-stash.$$"
TMPindex=${GIT_INDEX_FILE-"$(git rev-parse --git-path index)"}.stash.$$
trap 'rm -f "$TMP-"* "$TMPindex"' 0

ref_stash=refs/stash

if git config --get-colorbool color.interactive; then
       help_color="$(git config --get-color color.interactive.help 'red bold')"
       reset_color="$(git config --get-color '' reset)"
else
       help_color=
       reset_color=
fi

no_changes () {
        git diff-index --quiet --cached HEAD --ignore-submodules -- &&
        git diff-files --quiet --ignore-submodules &&
        (test -z "$untracked" || test -z "$(untracked_files)")
}

untracked_files () {
        excl_opt=--exclude-standard
        test "$untracked" = "all" && excl_opt=
        git ls-files -o -z $excl_opt
}

clear_stash () {
        if test $# != 0
        then
                die "$(gettext "git stash clear with parameters is unimplemented")"
        fi
        if current=$(git rev-parse --verify --quiet $ref_stash)
        then
                git update-ref -d $ref_stash $current
        fi
}

create_stash () {
        stash_msg="$1"
        untracked="$2"

        git update-index -q --refresh
        if no_changes
        then
                exit 0
        fi

        # state of the base commit
        if b_commit=$(git rev-parse --verify HEAD)
        then
                head=$(git rev-list --oneline -n 1 HEAD --)
        else
                die "$(gettext "You do not have the initial commit yet")"
        fi

        if branch=$(git symbolic-ref -q HEAD)
        then
                branch=${branch#refs/heads/}
        else
                branch='(no branch)'
        fi
        msg=$(printf '%s: %s' "$branch" "$head")

        # state of the index
        i_tree=$(git write-tree) &&
        i_commit=$(printf 'index on %s\n' "$msg" |
                git commit-tree $i_tree -p $b_commit) ||
                die "$(gettext "Cannot save the current index state")"

        if test -n "$untracked"
        then
                # Untracked files are stored by themselves in a parentless commit, for
                # ease of unpacking later.
                u_commit=$(
                        untracked_files | (
                                GIT_INDEX_FILE="$TMPindex" &&
                                export GIT_INDEX_FILE &&
                                rm -f "$TMPindex" &&
                                git update-index -z --add --remove --stdin &&
                                u_tree=$(git write-tree) &&
                                printf 'untracked files on %s\n' "$msg" | git commit-tree $u_tree  &&
                                rm -f "$TMPindex"
                ) ) || die "$(gettext "Cannot save the untracked files")"

                untracked_commit_option="-p $u_commit";
        else
                untracked_commit_option=
        fi

        if test -z "$patch_mode"
        then

                # state of the working tree
                w_tree=$( (
                        git read-tree --index-output="$TMPindex" -m $i_tree &&
                        GIT_INDEX_FILE="$TMPindex" &&
                        export GIT_INDEX_FILE &&
                        git diff --name-only -z HEAD -- >"$TMP-stagenames" &&
                        git update-index -z --add --remove --stdin <"$TMP-stagenames" &&
                        git write-tree &&
                        rm -f "$TMPindex"
                ) ) ||
                        die "$(gettext "Cannot save the current worktree state")"

        else

                rm -f "$TMP-index" &&
                GIT_INDEX_FILE="$TMP-index" git read-tree HEAD &&

                # find out what the user wants
                GIT_INDEX_FILE="$TMP-index" \
                        git add--interactive --patch=stash -- &&

                # state of the working tree
                w_tree=$(GIT_INDEX_FILE="$TMP-index" git write-tree) ||
                die "$(gettext "Cannot save the current worktree state")"

                git diff-tree -p HEAD $w_tree -- >"$TMP-patch" &&
                test -s "$TMP-patch" ||
                die "$(gettext "No changes selected")"

                rm -f "$TMP-index" ||
                die "$(gettext "Cannot remove temporary index (can't happen)")"

        fi

        # create the stash
        if test -z "$stash_msg"
        then
                stash_msg=$(printf 'WIP on %s' "$msg")
        else
                stash_msg=$(printf 'On %s: %s' "$branch" "$stash_msg")
        fi
        w_commit=$(printf '%s\n' "$stash_msg" |
        git commit-tree $w_tree -p $b_commit -p $i_commit $untracked_commit_option) ||
        die "$(gettext "Cannot record working tree state")"
}

store_stash () {
        while test $# != 0
        do
                case "$1" in
                -m|--message)
                        shift
                        stash_msg="$1"
                        ;;
                -q|--quiet)
                        quiet=t
                        ;;
                *)
                        break
                        ;;
                esac
                shift
        done
        test $# = 1 ||
        die "$(eval_gettext "\"$dashless store\" requires one <commit> argument")"

        w_commit="$1"
        if test -z "$stash_msg"
        then
                stash_msg="Created via \"git stash store\"."
        fi

        git update-ref --create-reflog -m "$stash_msg" $ref_stash $w_commit
        ret=$?
        test $ret != 0 && test -z "$quiet" &&
        die "$(eval_gettext "Cannot update \$ref_stash with \$w_commit")"
        return $ret
}

save_stash () {
        keep_index=
        patch_mode=
        untracked=
        while test $# != 0
        do
                case "$1" in
                -k|--keep-index)
                        keep_index=t
                        ;;
                --no-keep-index)
                        keep_index=n
                        ;;
                -p|--patch)
                        patch_mode=t
                        # only default to keep if we don't already have an override
                        test -z "$keep_index" && keep_index=t
                        ;;
                -q|--quiet)
                        GIT_QUIET=t
                        ;;
                -u|--include-untracked)
                        untracked=untracked
                        ;;
                -a|--all)
                        untracked=all
                        ;;
                --help)
                        show_help
                        ;;
                --)
                        shift
                        break
                        ;;
                -*)
                        option="$1"
                        # TRANSLATORS: $option is an invalid option, like
                        # `--blah-blah'. The 7 spaces at the beginning of the
                        # second line correspond to "error: ". So you should line
                        # up the second line with however many characters the
                        # translation of "error: " takes in your language. E.g. in
                        # English this is:
                        #
                        #    $ git stash save --blah-blah 2>&1 | head -n 2
                        #    error: unknown option for 'stash save': --blah-blah
                        #           To provide a message, use git stash save -- '--blah-blah'
                        eval_gettextln "error: unknown option for 'stash save': \$option
       To provide a message, use git stash save -- '\$option'"
                        usage
                        ;;
                *)
                        break
                        ;;
                esac
                shift
        done

        if test -n "$patch_mode" && test -n "$untracked"
        then
                die "$(gettext "Can't use --patch and --include-untracked or --all at the same time")"
        fi

        stash_msg="$*"

        git update-index -q --refresh
        if no_changes
        then
                say "$(gettext "No local changes to save")"
                exit 0
        fi
        git reflog exists $ref_stash ||
                clear_stash || die "$(gettext "Cannot initialize stash")"

        create_stash "$stash_msg" $untracked
        store_stash -m "$stash_msg" -q $w_commit ||
        die "$(gettext "Cannot save the current status")"
        say "$(eval_gettext "Saved working directory and index state \$stash_msg")"

        if test -z "$patch_mode"
        then
                git reset --hard ${GIT_QUIET:+-q}
                test "$untracked" = "all" && CLEAN_X_OPTION=-x || CLEAN_X_OPTION=
                if test -n "$untracked"
                then
                        git clean --force --quiet -d $CLEAN_X_OPTION
                fi

                if test "$keep_index" = "t" && test -n "$i_tree"
                then
                        git read-tree --reset -u $i_tree
                fi
        else
                git apply -R < "$TMP-patch" ||
                die "$(gettext "Cannot remove worktree changes")"

                if test "$keep_index" != "t"
                then
                        git reset
                fi
        fi
}

have_stash () {
        git rev-parse --verify --quiet $ref_stash >/dev/null
}

list_stash () {
        have_stash || return 0
        git log --format="%gd: %gs" -g --first-parent -m "$@" $ref_stash --
}

show_stash () {
        ALLOW_UNKNOWN_FLAGS=t
        assert_stash_like "$@"

        if test -z "$FLAGS"
        then
                if test "$(git config --bool stash.showStat || echo true)" = "true"
                then
                        FLAGS=--stat
                fi

                if test "$(git config --bool stash.showPatch || echo false)" = "true"
                then
                        FLAGS=${FLAGS}${FLAGS:+ }-p
                fi

                if test -z "$FLAGS"
                then
                        return 0
                fi
        fi

        git diff ${FLAGS} $b_commit $w_commit
}

show_help () {
        exec git help stash
        exit 1
}

#
# Parses the remaining options looking for flags and
# at most one revision defaulting to ${ref_stash}@{0}
# if none found.
#
# Derives related tree and commit objects from the
# revision, if one is found.
#
# stash records the work tree, and is a merge between the
# base commit (first parent) and the index tree (second parent).
#
#   REV is set to the symbolic version of the specified stash-like commit
#   IS_STASH_LIKE is non-blank if ${REV} looks like a stash
#   IS_STASH_REF is non-blank if the ${REV} looks like a stash ref
#   s is set to the SHA1 of the stash commit
#   w_commit is set to the commit containing the working tree
#   b_commit is set to the base commit
#   i_commit is set to the commit containing the index tree
#   u_commit is set to the commit containing the untracked files tree
#   w_tree is set to the working tree
#   b_tree is set to the base tree
#   i_tree is set to the index tree
#   u_tree is set to the untracked files tree
#
#   GIT_QUIET is set to t if -q is specified
#   INDEX_OPTION is set to --index if --index is specified.
#   FLAGS is set to the remaining flags (if allowed)
#
# dies if:
#   * too many revisions specified
#   * no revision is specified and there is no stash stack
#   * a revision is specified which cannot be resolve to a SHA1
#   * a non-existent stash reference is specified
#   * unknown flags were set and ALLOW_UNKNOWN_FLAGS is not "t"
#

parse_flags_and_rev()
{
        test "$PARSE_CACHE" = "$*" && return 0 # optimisation
        PARSE_CACHE="$*"

        IS_STASH_LIKE=
        IS_STASH_REF=
        INDEX_OPTION=
        s=
        w_commit=
        b_commit=
        i_commit=
        u_commit=
        w_tree=
        b_tree=
        i_tree=
        u_tree=

        REV=$(git rev-parse --no-flags --symbolic --sq "$@") || exit 1

        FLAGS=
        for opt
        do
                case "$opt" in
                        -q|--quiet)
                                GIT_QUIET=-t
                        ;;
                        --index)
                                INDEX_OPTION=--index
                        ;;
                        --help)
                                show_help
                        ;;
                        -*)
                                test "$ALLOW_UNKNOWN_FLAGS" = t ||
                                        die "$(eval_gettext "unknown option: \$opt")"
                                FLAGS="${FLAGS}${FLAGS:+ }$opt"
                        ;;
                esac
        done

        eval set -- $REV

        case $# in
                0)
                        have_stash || die "$(gettext "No stash found.")"
                        set -- ${ref_stash}@{0}
                ;;
                1)
                        :
                ;;
                *)
                        die "$(eval_gettext "Too many revisions specified: \$REV")"
                ;;
        esac

        REV=$(git rev-parse --symbolic --verify --quiet "$1") || {
                reference="$1"
                die "$(eval_gettext "\$reference is not a valid reference")"
        }

        i_commit=$(git rev-parse --verify --quiet "$REV^2") &&
        set -- $(git rev-parse "$REV" "$REV^1" "$REV:" "$REV^1:" "$REV^2:" 2>/dev/null) &&
        s=$1 &&
        w_commit=$1 &&
        b_commit=$2 &&
        w_tree=$3 &&
        b_tree=$4 &&
        i_tree=$5 &&
        IS_STASH_LIKE=t &&
        test "$ref_stash" = "$(git rev-parse --symbolic-full-name "${REV%@*}")" &&
        IS_STASH_REF=t

        u_commit=$(git rev-parse --verify --quiet "$REV^3") &&
        u_tree=$(git rev-parse "$REV^3:" 2>/dev/null)
}

is_stash_like()
{
        parse_flags_and_rev "$@"
        test -n "$IS_STASH_LIKE"
}

assert_stash_like() {
        is_stash_like "$@" || {
                args="$*"
                die "$(eval_gettext "'\$args' is not a stash-like commit")"
        }
}

is_stash_ref() {
        is_stash_like "$@" && test -n "$IS_STASH_REF"
}

assert_stash_ref() {
        is_stash_ref "$@" || {
                args="$*"
                die "$(eval_gettext "'\$args' is not a stash reference")"
        }
}

apply_stash () {

        assert_stash_like "$@"

        git update-index -q --refresh || die "$(gettext "unable to refresh index")"

        # current index state
        c_tree=$(git write-tree) ||
                die "$(gettext "Cannot apply a stash in the middle of a merge")"

        unstashed_index_tree=
        if test -n "$INDEX_OPTION" && test "$b_tree" != "$i_tree" &&
                        test "$c_tree" != "$i_tree"
        then
                git diff-tree --binary $s^2^..$s^2 | git apply --cached
                test $? -ne 0 &&
                        die "$(gettext "Conflicts in index. Try without --index.")"
                unstashed_index_tree=$(git write-tree) ||
                        die "$(gettext "Could not save index tree")"
                git reset
        fi

        if test -n "$u_tree"
        then
                GIT_INDEX_FILE="$TMPindex" git-read-tree "$u_tree" &&
                GIT_INDEX_FILE="$TMPindex" git checkout-index --all &&
                rm -f "$TMPindex" ||
                die "$(gettext "Could not restore untracked files from stash")"
        fi

        eval "
                GITHEAD_$w_tree='Stashed changes' &&
                GITHEAD_$c_tree='Updated upstream' &&
                GITHEAD_$b_tree='Version stash was based on' &&
                export GITHEAD_$w_tree GITHEAD_$c_tree GITHEAD_$b_tree
        "

        if test -n "$GIT_QUIET"
        then
                GIT_MERGE_VERBOSITY=0 && export GIT_MERGE_VERBOSITY
        fi
        if git merge-recursive $b_tree -- $c_tree $w_tree
        then
                # No conflict
                if test -n "$unstashed_index_tree"
                then
                        git read-tree "$unstashed_index_tree"
                else
                        a="$TMP-added" &&
                        git diff-index --cached --name-only --diff-filter=A $c_tree >"$a" &&
                        git read-tree --reset $c_tree &&
                        git update-index --add --stdin <"$a" ||
                                die "$(gettext "Cannot unstage modified files")"
                        rm -f "$a"
                fi
                squelch=
                if test -n "$GIT_QUIET"
                then
                        squelch='>/dev/null 2>&1'
                fi
                (cd "$START_DIR" && eval "git status $squelch") || :
        else
                # Merge conflict; keep the exit status from merge-recursive
                status=$?
                git rerere
                if test -n "$INDEX_OPTION"
                then
                        gettextln "Index was not unstashed." >&2
                fi
                exit $status
        fi
}

pop_stash() {
        assert_stash_ref "$@"

        if apply_stash "$@"
        then
                drop_stash "$@"
        else
                status=$?
                say "$(gettext "The stash is kept in case you need it again.")"
                exit $status
        fi
}

drop_stash () {
        assert_stash_ref "$@"

        git reflog delete --updateref --rewrite "${REV}" &&
                say "$(eval_gettext "Dropped \${REV} (\$s)")" ||
                die "$(eval_gettext "\${REV}: Could not drop stash entry")"

        # clear_stash if we just dropped the last stash entry
        git rev-parse --verify --quiet "$ref_stash@{0}" >/dev/null ||
        clear_stash
}

apply_to_branch () {
        test -n "$1" || die "$(gettext "No branch name specified")"
        branch=$1
        shift 1

        set -- --index "$@"
        assert_stash_like "$@"

        git checkout -b $branch $REV^ &&
        apply_stash "$@" && {
                test -z "$IS_STASH_REF" || drop_stash "$@"
        }
}

PARSE_CACHE='--not-parsed'
# The default command is "save" if nothing but options are given
seen_non_option=
for opt
do
        case "$opt" in
        -*) ;;
        *) seen_non_option=t; break ;;
        esac
done

test -n "$seen_non_option" || set "save" "$@"

# Main command set
case "$1" in
list)
        shift
        list_stash "$@"
        ;;
show)
        shift
        show_stash "$@"
        ;;
save)
        shift
        save_stash "$@"
        ;;
apply)
        shift
        apply_stash "$@"
        ;;
clear)
        shift
        clear_stash "$@"
        ;;
create)
        shift
        create_stash "$*" && echo "$w_commit"
        ;;
store)
        shift
        store_stash "$@"
        ;;
drop)
        shift
        drop_stash "$@"
        ;;
pop)
        shift
        pop_stash "$@"
        ;;
branch)
        shift
        apply_to_branch "$@"
        ;;
*)
        case $# in
        0)
                save_stash &&
                say "$(gettext "(To restore them type \"git stash apply\")")"
                ;;
        *)
                usage
        esac
        ;;
esac