#!/usr/bin/env python3
# trunk-ignore-all(ruff/F821)
# trunk-ignore-all(flake8/F821): For SConstruct imports
#
# Registers optional modules dropped into src/modules/optional/.
#
# A module is a directory <Name>/ holding <Name>.h, which declares `void setup<Name>();`. This
# writes $BUILD_DIR/OptionalModules.h with an include and a setup call for each one found;
# Modules.cpp picks that header up through __has_include and calls OPTIONAL_MODULES_SETUP().
#
# src/modules/optional/ does not exist in a stock checkout, so a stock build generates a header that
# defines nothing and registers nothing. Sources under the directory are compiled by the default
# recursive build_src_filter, so dropping a module in needs no platformio.ini edit.
import os
import re

Import("env")

# The directory name becomes a C++ call, so it has to be a usable identifier.
identifier = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*$")

optionalDir = os.path.join(env["PROJECT_DIR"], "src", "modules", "optional")

names = []
if os.path.isdir(optionalDir):
    for entry in sorted(os.listdir(optionalDir)):
        entryDir = os.path.join(optionalDir, entry)
        if not os.path.isdir(entryDir):
            continue
        if not identifier.match(entry):
            print(f"optional-modules: skipping {entry}/, setup{entry}() is not a valid identifier")
        elif os.path.isfile(os.path.join(entryDir, entry + ".h")):
            names.append(entry)
        else:
            print(f"optional-modules: skipping {entry}/, no {entry}.h")

lines = ["// Generated by bin/optional-modules.py. Do not edit.", "#pragma once", ""]
for name in names:
    lines.append(f'#include "modules/optional/{name}/{name}.h"')
if names:
    lines.append("")
    lines.append("#define OPTIONAL_MODULES_SETUP() \\")
    lines.append("    do { \\")
    for name in names:
        lines.append(f"        setup{name}(); \\")
    lines.append("    } while (0)")
lines.append("")
content = "\n".join(lines)

buildDir = env.subst("$BUILD_DIR")
os.makedirs(buildDir, exist_ok=True)
header = os.path.join(buildDir, "OptionalModules.h")

# Rewrite only on a change, so an unchanged set of modules does not keep rebuilding Modules.cpp.
previous = None
if os.path.isfile(header):
    with open(header, encoding="utf-8") as f:
        previous = f.read()
if previous != content:
    with open(header, "w", encoding="utf-8") as f:
        f.write(content)

env.Append(CPPPATH=[buildDir])

if names:
    print("optional-modules: " + ", ".join(names))