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 `nanopb_protos` specified, exiting.")
    exit(0)

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)