shell_find_runfiles = """
  # --- begin runfiles.bash initialization ---
  # Copy-pasted from Bazel's Bash runfiles library (tools/bash/runfiles/runfiles.bash).
  set -euo pipefail
  if [[ ! -d "${RUNFILES_DIR:-/dev/null}" && ! -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" ]]; then
    if [[ -f "$0.runfiles_manifest" ]]; then
      export RUNFILES_MANIFEST_FILE="$0.runfiles_manifest"
    elif [[ -f "$0.runfiles/MANIFEST" ]]; then
      export RUNFILES_MANIFEST_FILE="$0.runfiles/MANIFEST"
    elif [[ -f "$0.runfiles/bazel_tools/tools/bash/runfiles/runfiles.bash" ]]; then
      export RUNFILES_DIR="$0.runfiles"
    fi
  fi
  if [[ -f "${RUNFILES_DIR:-/dev/null}/bazel_tools/tools/bash/runfiles/runfiles.bash" ]]; then
    source "${RUNFILES_DIR}/bazel_tools/tools/bash/runfiles/runfiles.bash"
  elif [[ -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" ]]; then
    source "$(grep -m1 "^bazel_tools/tools/bash/runfiles/runfiles.bash " \
              "$RUNFILES_MANIFEST_FILE" | cut -d ' ' -f 2-)"
  else
    echo >&2 "ERROR: cannot find @bazel_tools//tools/bash/runfiles:runfiles.bash"
    exit 1
  fi
  # --- end runfiles.bash initialization ---
"""

def _librule(name):
    return name + "_lib"

def lua_cclibrary(name, srcs, hdrs = [], deps = [], luadeps = []):
    lib_rule = name + "_lib"
    so_rule = "lib" + name + ".so"
    so_file = _remove_prefix(name, "lua/") + ".so"

    native.cc_library(
        name = _librule(name),
        hdrs = hdrs,
        srcs = srcs,
        deps = deps + [_librule(dep) for dep in luadeps] + ["@lua//:liblua_headers"],
    )

    native.cc_binary(
        name = so_rule,
        linkshared = True,
        deps = [_librule(name)],
    )

    native.genrule(
        name = name + "_copy",
        srcs = [":" + so_rule],
        outs = [so_file],
        cmd = "cp $< $@",
    )

    native.filegroup(
        name = name,
        data = [so_file],
    )

def _remove_prefix(str, prefix):
    if not str.startswith(prefix):
        fail("%s doesn't start with %s" % (str, prefix))
    return str[len(prefix):]

def lua_library(name, srcs, base, luadeps = []):
    outs = [_remove_prefix(src, base + "/") for src in srcs]
    native.genrule(
        name = name + "_copy",
        srcs = srcs,
        outs = outs,
        cmd = "cp $(SRCS) $(@D)",
    )

    native.filegroup(
        name = name,
        data = outs + luadeps,
    )

def lua_binary(name, main, luadeps=[]):
    script = name + ".sh"

    script_contents = (shell_find_runfiles + """
BASE=$(dirname $(rlocation upb/upb_c.so))
export LUA_CPATH="$BASE/?.so"
export LUA_PATH="$BASE/?.lua"
$(rlocation lua/lua) $(rlocation upb/tools/upbc.lua) "$@"
""").replace("$", "$$")
    print(native.repository_name())

    native.genrule(
        name = "gen_" + name,
        outs = [script],
        cmd = "(cat <<'HEREDOC'\n%s\nHEREDOC\n) > $@" % script_contents,
    )
    native.sh_binary(
        name = name,
        srcs = [script],
        data = ["@lua//:lua", "@bazel_tools//tools/bash/runfiles", main] + luadeps,
    )