#!/bin/sh
set -e

# stg-gitk - helper script to graphically display an StGit stack

# Displays given branches and stacks, without getting disturbed by
# patch logs.

# LIMITATIONS:
# - no support for spaces in branch names

# Copyright (c) 2007 Yann Dirson <ydirson@altern.org>
# Subject to the GNU GPL, version 2.

helptext="Usage: $(basename "$0") [--refs] [<branches>|--all] [-- <gitk args>]"

usage()
{
    echo >&2 "$helptext"
    exit 1
}

allbranches=0
refsonly=0
branches=''
while [ "$#" -gt 0 ]; do
    case "$1" in
        --refs) refsonly=1 ;;
        --all) allbranches=1 ;;
        --help) echo "$helptext"; exit 0 ;;
        --) shift; break ;;
        --*) usage ;;
        *) branches="$branches $1" ;;
    esac
    shift
done
# Now any remaining stuff in $@ are additional options for gitk

if [ $allbranches = 1 ] && [ "$branches" != "" ]; then
    usage
fi

GIT_DIR=$(git rev-parse --git-dir)
GIT_DIR_SKIPLEN=$(printf "%s/X" "$GIT_DIR" | wc -c)

refdirs=''
if [ $allbranches = 1 ]; then
    refdirs="$GIT_DIR/refs"
else
    # default to current branch
    if [ "$branches" = "" ]; then
        branches="$(stg branch)"
    fi
    if [ "$branches" = "" ]; then
        echo >&2 "ERROR: cannot find current branch."
        exit 1
    fi

    # expand patches for each named branch
    for b in $branches; do
        if [ -e "$GIT_DIR/refs/patches/$b" ]; then
            # StGit branch: show all patches
            refdirs="$refdirs $GIT_DIR/refs/heads/$b $GIT_DIR/refs/patches/$b"
        elif [ -e "$GIT_DIR/refs/heads/$b" ]; then
            # other Git branch
            refdirs="$refdirs $GIT_DIR/refs/heads/$b"
        elif [ "$(git for-each-ref "refs/$b" | wc -l)" != 0 ]; then
            # other ref
            refdirs="$refdirs $(git for-each-ref --format="$GIT_DIR/%(refname)" "refs/$b")"
        else
            echo >&2 "ERROR: no such ref '$b'"
            usage
        fi
    done
fi

printrefs()
{
    # shellcheck disable=SC2086
    find $refdirs -type f -not -name '*.log' | cut -c"${GIT_DIR_SKIPLEN}"-
}

if [ $refsonly = 1 ]; then
    printrefs
elif grep -q -- --argscmd "$(command -v gitk)"; then
    # This gitk supports --argscmd.
    # Let's use a hack to pass --all, which was consumed during command-line parsing
    if [ $allbranches = 1 ]; then
        gitk --argscmd="$0 --refs --all" "$@"
    else
        gitk --argscmd="$0 --refs $branches" "$@"
    fi
else
    # This gitk does not support --argscmd, just compute refs once
    # shellcheck disable=SC2046
    gitk $(printrefs) "$@"
fi