# --- enable/disable this file ---
SRC_ENABLED=true

case "$SRC_ENABLED" in
	1|true|yes|on) unset SRC_ENABLED ;;           # enabled — clean up and continue
	*) unset SRC_ENABLED; return ;;                # disabled — clean up and skip this file
esac
# ---------------------------------

bash_pstree()
{
    local root_pid="${1:-1}"
    local procdir pid key value name ppid idx

    PIDS=()
    PPIDS=()
    NAMES=()
    idx=0

    #
    # Build process table from /proc/*/status.
    #
    for procdir in /proc/[0-9]*; do
        [[ -d "$procdir" ]] || continue
        [[ -r "$procdir/status" ]] || continue
        pid="${procdir#/proc/}"
        name=""
        ppid=""
        while IFS=: read -r key value; do
            value="${value#"${value%%[![:space:]]*}"}"
            case "$key" in
                Name) name="$value" ;;
                PPid) ppid="$value" ;;
            esac
        done < "$procdir/status"
        [[ -n "$ppid" ]] || continue
        PIDS[$idx]="$pid"
        PPIDS[$idx]="$ppid"
        NAMES[$idx]="${name:-?}"
        idx=$((idx + 1))
    done

    bash_pstree_set_chars
    bash_pstree_root "$root_pid"
}

#
# Pick UTF-8 box-drawing chars if the locale supports them, else
# fall back to plain ASCII (works on any RHEL5 console/terminal).
#
bash_pstree_set_chars()
{
    local charmap
    charmap=$(locale charmap 2>/dev/null)

    if [[ "$charmap" == "UTF-8" ]]; then
        BPT_VERT="│   "
        BPT_TEE="├── "
        BPT_LAST="└── "
    else
        BPT_VERT="|   "
        BPT_TEE="|-- "
        BPT_LAST="\`-- "
    fi
}

bash_pstree_find_name()
{
    local target="$1"
    local i
    for ((i = 0; i < ${#PIDS[@]}; i++)); do
        if [[ "${PIDS[$i]}" == "$target" ]]; then
            printf '%s' "${NAMES[$i]}"
            return 0
        fi
    done
    return 1
}

#
# Print numerically-sorted child PIDs of $1, one per line.
#
bash_pstree_children()
{
    local parent="$1"
    local i list
    list=""
    for ((i = 0; i < ${#PIDS[@]}; i++)); do
        if [[ "${PPIDS[$i]}" == "$parent" ]]; then
            list="$list${PIDS[$i]}
"
        fi
    done
    [[ -n "$list" ]] && printf '%s' "$list" | sort -n
}

bash_pstree_root()
{
    local pid="$1" name
    name=$(bash_pstree_find_name "$pid") || return
    printf '%s(%s)\n' "$name" "$pid"
    bash_pstree_show_children "$pid" ""
}

#
# $1 = parent pid, $2 = prefix accumulated so far
#
bash_pstree_show_children()
{
    local parent="$1" prefix="$2"
    local child name last_line

    local children
    children=$(bash_pstree_children "$parent")
    [[ -n "$children" ]] || return

    last_line=$(printf '%s\n' "$children" | tail -n 1)

    while IFS= read -r child; do
        [[ -n "$child" ]] || continue
        name=$(bash_pstree_find_name "$child") || continue
        if [[ "$child" == "$last_line" ]]; then
            printf '%s%s%s(%s)\n' "$prefix" "$BPT_LAST" "$name" "$child"
            bash_pstree_show_children "$child" "${prefix}    "
        else
            printf '%s%s%s(%s)\n' "$prefix" "$BPT_TEE" "$name" "$child"
            bash_pstree_show_children "$child" "${prefix}${BPT_VERT}"
        fi
    done <<< "$children"
}

#
# Wrapper:
#
#   pstree_compat
#   pstree_compat 1234
#
pstree_compat()
{
    local root_pid="${1:-1}"
    if command -v pstree >/dev/null 2>&1; then
        pstree -p "$root_pid"
    else
        bash_pstree "$root_pid"
    fi
}

alias pstree='pstree_compat'