import os
import hashlib
import pathlib
from platformio import fs

Import("env")

nanopb_root = os.path.join(os.getcwd(), '..')

project_dir = env.subst("$PROJECT_DIR")
build_dir = env.subst("$BUILD_DIR")

generated_src_dir = os.path.join(build_dir, 'nanopb', 'generated-src')
generated_build_dir = os.path.join(build_dir, 'nanopb', 'generated-build')
md5_dir = os.path.join(build_dir, 'nanopb', 'md5')

nanopb_protos = env.GetProjectOption("nanopb_protos", "")
nanopb_plugin_options = env.GetProjectOption("nanopb_options", "")

if not nanopb_protos:
    print("[nanopb] No generation needed.")
else:
    if isinstance(nanopb_plugin_options, (list, tuple)):
        nanopb_plugin_options = " ".join(nanopb_plugin_options)

    nanopb_plugin_options = nanopb_plugin_options.split()

    protos_files = fs.match_src_files(project_dir, nanopb_protos)
    if not len(protos_files):
        print("[nanopb] ERROR: No files matched pattern:")
        print(f"nanopb_protos: {nanopb_protos}")
        exit(1)

    protoc_generator = os.path.join(nanopb_root, 'generator', 'protoc')

    nanopb_options = ""
    nanopb_options += f" --nanopb_out={generated_src_dir}"
    for opt in nanopb_plugin_options:
        nanopb_options += (" --nanopb_opt=" + opt)

    try:
        os.makedirs(generated_src_dir)
    except FileExistsError:
        pass

    try:
        os.makedirs(md5_dir)
    except FileExistsError:
        pass

    # Collect include dirs based on
    proto_include_dirs = set()
    for proto_file in protos_files:
        proto_file_abs = os.path.join(project_dir, proto_file)
        proto_dir = os.path.dirname(proto_file_abs)
        proto_include_dirs.add(proto_dir)

    for proto_include_dir in proto_include_dirs:
        nanopb_options += (" --proto_path=" + proto_include_dir)
        nanopb_options += (" --nanopb_opt=-I" + proto_include_dir)

    for proto_file in protos_files:
        proto_file_abs = os.path.join(project_dir, proto_file)

        proto_file_path_abs = os.path.dirname(proto_file_abs)
        proto_file_basename = os.path.basename(proto_file_abs)
        proto_file_without_ext = os.path.splitext(proto_file_basename)[0]

        proto_file_md5_abs = os.path.join(md5_dir, proto_file_basename + '.md5')
        proto_file_current_md5 = hashlib.md5(pathlib.Path(proto_file_abs).read_bytes()).hexdigest()

        options_file = proto_file_without_ext + ".options"
        options_file_abs = os.path.join(proto_file_path_abs, options_file)
        options_file_md5_abs = None
        options_file_current_md5 = None
        if pathlib.Path(options_file_abs).exists():
            options_file_md5_abs = os.path.join(md5_dir, options_file + '.md5')
            options_file_current_md5 = hashlib.md5(pathlib.Path(options_file_abs).read_bytes()).hexdigest()
        else:
            options_file = None

        header_file = proto_file_without_ext + ".pb.h"
        source_file = proto_file_without_ext + ".pb.c"

        header_file_abs = os.path.join(generated_src_dir, source_file)
        source_file_abs = os.path.join(generated_src_dir, header_file)

        need_generate = False

        # Check proto file md5
        try:
            last_md5 = pathlib.Path(proto_file_md5_abs).read_text()
            if last_md5 != proto_file_current_md5:
                need_generate = True
        except FileNotFoundError:
            need_generate = True

        if options_file:
            # Check options file md5
            try:
                last_md5 = pathlib.Path(options_file_md5_abs).read_text()
                if last_md5 != options_file_current_md5:
                    need_generate = True
            except FileNotFoundError:
                need_generate = True

        options_info = f"{options_file}" if options_file else "no options"

        if not need_generate:
            print(f"[nanopb] Skipping '{proto_file}' ({options_info})")
        else:
            print(f"[nanopb] Processing '{proto_file}' ({options_info})")
            cmd = protoc_generator + " " + nanopb_options + " " + proto_file_basename
            result = env.Execute(cmd)
            if result != 0:
                print(f"[nanopb] ERROR: ({result}) processing cmd: '{cmd}'")
                exit(1)
            pathlib.Path(proto_file_md5_abs).write_text(proto_file_current_md5)
            if options_file:
                pathlib.Path(options_file_md5_abs).write_text(options_file_current_md5)

    #
    # Add generated includes and sources to build environment
    #
    env.Append(CPPPATH=[generated_src_dir])
    env.BuildSources(generated_build_dir, generated_src_dir)