# Copyright (c) 2025, NVIDIA CORPORATION.
# SPDX-License-Identifier: BSD-3-Clause

"""This module tests the EPath class, our custom version of pathlib.Path"""

import logging
import multiprocessing
import os
import pickle
import struct
import sys
import unittest

from megatron.energon.epathlib import EPath
from tests.epath_s3_emulator import setup_s3_emulator


class TestEPath(unittest.TestCase):
    def setUp(self):
        logging.basicConfig(stream=sys.stderr, level=logging.INFO)

    def tearDown(self):
        pass

    def test_basic(self):
        """Some basic functionality tests"""

        p_rel = EPath("./subdir")
        p_abs = EPath("/tmp")

        p_comb = p_abs / p_rel
        # Those should not raise:
        assert not p_comb.is_file()
        assert not p_abs.is_file()
        assert p_abs.is_dir()

    def test_contextman(self):
        """Test the context manager"""

        tmp_file_path = "/tmp/testfile.bin"
        # First create a file
        with open(tmp_file_path, "wb") as f:
            f.write(struct.pack("H10s", 1337, b"1234567890"))

        # Test context manager reading
        p = EPath(tmp_file_path).open("rb")
        print(p)
        with p:
            b = p.read()
            assert isinstance(b, bytes)

            num, data = struct.unpack("H10s", b)
            logging.info(f"num: {num}")
            assert num == 1337
            assert data == b"1234567890"

        # Test context manager writing
        tmp_file_path2 = "/tmp/testfile2.bin"
        with EPath(tmp_file_path2).open("wb") as p:
            p.write(struct.pack("H10s", 1337, b"1234567890"))

    def test_localfs(self):
        """Test the local filesystem"""
        p = EPath("/tmp/testfile.bin")
        with p.open("wb") as f:
            f.write(b"dummycontent")
        assert p.is_file()
        assert p.size() == 12
        with p.open("rb") as f:
            assert f.read() == b"dummycontent"

        # Test relative paths
        revert_dir = os.getcwd()
        try:
            os.chdir("/tmp")
            p = EPath("testfile.bin")
            assert str(p) == "/tmp/testfile.bin"
            assert p.is_file()
            assert p.size() == 12
            with p.open("rb") as f:
                assert f.read() == b"dummycontent"

            p = EPath("nonexisting/../testfile.bin")
            assert str(p) == "/tmp/testfile.bin"

            p = EPath("../tmp/testfile.bin")
            assert str(p) == "/tmp/testfile.bin"
        finally:
            os.chdir(revert_dir)

        p.unlink()
        assert p.is_file() is False

    def test_glob(self):
        """Test the glob functionality"""

        # First create some files
        for i in range(10):
            with open(f"/tmp/epathtestfile_{i}.bin", "wb") as f:
                f.write(b"dummycontent")

        # Test globbing
        p = EPath("/tmp").glob("epathtestfile_*.bin")

        logging.info(f"p: {p}, type of p: {type(p)}")
        elems = list(p)
        assert len(elems) == 10
        for i, e in enumerate(elems):
            logging.info(f"glob_result[{i}]: {e}")
            assert isinstance(e, EPath)
            assert e.is_file()

        # Test globbing with a pattern
        p = EPath("/tmp").glob("epathtestfile_[0-3].bin")
        assert len(list(p)) == 4

    def test_s3_path_resolution(self):
        """Test s3 path resolution"""
        rclone_config_path = EPath("/tmp/XDG_CONFIG_HOME/.config/rclone/rclone.conf")
        with rclone_config_path.open("w") as f:
            f.write(
                "\n".join(
                    [
                        "[s3]",
                        "type = s3",
                        "env_auth = false",
                        "access_key_id = dummy",
                        "secret_access_key = dummy",
                        "region = dummy",
                        "endpoint = https://localhost",
                    ]
                )
            )

        orig_xdg_config_home = os.environ.get("XDG_CONFIG_HOME")
        os.environ["XDG_CONFIG_HOME"] = "/tmp/XDG_CONFIG_HOME/.config"
        os.environ["HOME"] = "/tmp/XDG_CONFIG_HOME"
        # Hack to clear the cache of the rclone config for msc to get the "s3" profile
        from multistorageclient.rclone import read_rclone_config

        read_rclone_config.cache_clear()
        try:
            # Test globbing
            p = EPath("msc://s3/tmp/path/subpath.txt")
            assert str(p) == "msc://s3/tmp/path/subpath.txt", str(p)

            p2 = p / ".." / "subpath2.txt"
            assert str(p2) == "msc://s3/tmp/path/subpath2.txt", str(p2)

            p3 = EPath("msc://s3/tmp/path/.././subpath.txt")
            assert str(p3) == "msc://s3/tmp/subpath.txt", str(p3)

            p4 = p3.parent / "../bla/bla/bla/../../../no/../subpath2.txt"
            assert str(p4) == "msc://s3/subpath2.txt", str(p4)

            # Test warning for deprecated rclone protocol
            with self.assertWarns((DeprecationWarning, FutureWarning)) as warning:
                # Test rclone backwards compatibility
                pr = EPath("rclone://s3/tmp/path/.././subpath.txt")
                assert str(pr) == "msc://s3/tmp/subpath.txt", str(pr)
            assert "deprecated" in str(warning.warnings[0].message)

            # Test pickle / unpickle
            p4serialized = pickle.dumps(p4)
            # No secret must be serialized
            assert b"dummy" not in p4serialized
        finally:
            if orig_xdg_config_home is not None:
                os.environ["XDG_CONFIG_HOME"] = orig_xdg_config_home
            else:
                del os.environ["XDG_CONFIG_HOME"]
            rclone_config_path.unlink()

    def test_multi_storage_client(self):
        """Test the Multi-Storage Client integration"""
        # Test path handling
        p = EPath("msc://default/etc/resolv.conf")
        assert str(p) == "/etc/resolv.conf", str(p)
        assert p.is_file()

        p2 = p / ".." / "hosts"
        assert str(p2) == "/etc/hosts", str(p2)

        # Test glob
        p3 = EPath("msc://default/etc/")
        assert p3.is_dir()
        for i in p3.glob("*.conf"):
            assert str(i).endswith(".conf")

        # Test open file
        assert p.size() > 0
        with p.open("r") as fp:
            assert len(fp.read()) > 0

        # Test move and delete
        p4 = EPath("msc://default/tmp/random_file_0001")
        p4.unlink()
        with p4.open("w") as fp:
            fp.write("*****")
        assert p4.is_file()
        p5 = EPath("msc://default/tmp/random_file_0002")
        p5.unlink()
        assert p5.is_file() is False
        p4.move(p5)
        assert p5.is_file()
        assert p4.is_file() is False
        p5.unlink()
        assert p5.is_file() is False

        # Test pickle / unpickle
        p5serialized = pickle.dumps(p5)
        p5unserialized = pickle.loads(p5serialized)
        assert p5unserialized == p5
        assert str(p5unserialized) == str(p5)

    def test_multiprocessing(self):
        """Test EPath in multiprocessing context"""
        p = EPath("/tmp/path/subpath.txt")

        orig_start_method = multiprocessing.get_start_method()
        try:
            multiprocessing.set_start_method("spawn", force=True)

            proc = multiprocessing.Process(target=_multiproc_test_func, args=(p, True))
            proc.start()
            proc.join()
            assert proc.exitcode == 0

            multiprocessing.set_start_method("fork", force=True)

            proc = multiprocessing.Process(target=_multiproc_test_func, args=(p, True))
            proc.start()
            proc.join()
            assert proc.exitcode == 0
        finally:
            multiprocessing.set_start_method(orig_start_method, force=True)

    def test_multiprocessing_msc(self):
        """Test EPath in multiprocessing context"""
        p = EPath("msc://default/tmp/random_file_0001")
        with p.open("w") as fp:
            fp.write("*****")

        orig_start_method = multiprocessing.get_start_method()
        try:
            multiprocessing.set_start_method("spawn", force=True)

            proc = multiprocessing.Process(target=_multiproc_test_func, args=(p, True))
            proc.start()
            proc.join()
            assert proc.exitcode == 0

            multiprocessing.set_start_method("fork", force=True)

            proc = multiprocessing.Process(target=_multiproc_test_func, args=(p, True))
            proc.start()
            proc.join()
            assert proc.exitcode == 0
        finally:
            multiprocessing.set_start_method(orig_start_method, force=True)
            p.unlink()

    def test_msc_s3(self):
        # Test S3 with MSC
        with setup_s3_emulator(profile_name="s3test_msc"):
            p = EPath("msc://s3test_msc/test/dir/file.txt")
            assert not p.is_file()
            p.write_text("dummy")
            assert p.is_file()
            assert p.size() > 0
            assert p.read_text() == "dummy"
            # TODO: Fix when fixed in MSC.
            # assert EPath("msc://s3test_msc/test").is_dir()
            assert EPath("msc://s3test_msc/test/dir").is_dir()
            p.unlink()
            assert not p.is_file()
            # assert not EPath("msc://s3test_msc/test").is_dir()
            assert not EPath("msc://s3test_msc/test/dir").is_dir()


def _multiproc_test_func(p: EPath, test_function: bool):
    """Helper function for multiprocessing test"""
    print(f"str: {str(p)}")
    if test_function:
        print(f"is_file: {p.is_file()}")


if __name__ == "__main__":
    unittest.main()