# Copyright The Lightning AI team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import os
from unittest import mock

import pytest

from lightning.fabric.plugins.environments import LSFEnvironment


def _make_rankfile(tmp_path):
    hosts = "batch\n10.10.10.0\n10.10.10.1\n10.10.10.2\n10.10.10.3"
    p = tmp_path / "lsb_djob_rankfile"
    p.write_text(hosts)
    return str(p)


@mock.patch.dict(os.environ, {"LSB_JOBID": "1234"})
def test_missing_lsb_djob_rankfile():
    """Test an error when the LSB_DJOB_RANKFILE cannot be found."""
    with pytest.raises(ValueError, match="Did not find the environment variable `LSB_DJOB_RANKFILE`"):
        LSFEnvironment()


@mock.patch.dict(os.environ, {"LSB_DJOB_RANKFILE": "", "LSB_JOBID": "1234"})
def test_empty_lsb_djob_rankfile():
    """Test an error when the LSB_DJOB_RANKFILE is not populated."""
    with pytest.raises(ValueError, match="The environment variable `LSB_DJOB_RANKFILE` is empty"):
        LSFEnvironment()


def test_missing_lsb_job_id(tmp_path):
    """Test an error when the job id cannot be found."""
    with mock.patch.dict(os.environ, {"LSB_DJOB_RANKFILE": _make_rankfile(tmp_path)}), pytest.raises(
        ValueError, match="Could not find job id in environment variable LSB_JOBID"
    ):
        LSFEnvironment()


def test_manual_main_port_and_address(tmp_path):
    """Test a user can set the port manually through the MASTER_PORT env variable."""
    environ = {
        "LSB_DJOB_RANKFILE": _make_rankfile(tmp_path),
        "LSB_JOBID": "1234",
        "JSM_NAMESPACE_SIZE": "4",
        "JSM_NAMESPACE_RANK": "3",
        "JSM_NAMESPACE_LOCAL_RANK": "1",
    }
    with mock.patch.dict(os.environ, environ), mock.patch("socket.gethostname", return_value="10.10.10.2"):
        env = LSFEnvironment()
        assert env.main_port == 10234


def test_attributes_from_environment_variables(tmp_path):
    """Test that the LSF environment takes the attributes from the environment variables."""
    environ = {
        "LSB_DJOB_RANKFILE": _make_rankfile(tmp_path),
        "LSB_JOBID": "1234",
        "JSM_NAMESPACE_SIZE": "4",
        "JSM_NAMESPACE_RANK": "3",
        "JSM_NAMESPACE_LOCAL_RANK": "1",
    }
    with mock.patch.dict(os.environ, environ), mock.patch("socket.gethostname", return_value="10.10.10.2"):
        env = LSFEnvironment()
        assert env.creates_processes_externally
        assert env.main_address == "10.10.10.0"
        assert env.main_port == 10234
        assert env.world_size() == 4
        assert env.global_rank() == 3
        assert env.local_rank() == 1
        env.set_global_rank(100)
        assert env.global_rank() == 3
        env.set_world_size(100)
        assert env.world_size() == 4
        assert LSFEnvironment.detect()


def test_node_rank(tmp_path):
    environ = {
        "LSB_DJOB_RANKFILE": _make_rankfile(tmp_path),
        "LSB_JOBID": "1234",
        "JSM_NAMESPACE_SIZE": "4",
        "JSM_NAMESPACE_RANK": "3",
        "JSM_NAMESPACE_LOCAL_RANK": "1",
    }
    with mock.patch.dict(os.environ, environ), mock.patch("socket.gethostname", return_value="10.10.10.2"):
        env = LSFEnvironment()
        assert env.node_rank() == 2


def test_detect():
    """Test the detection of a LSF environment configuration."""
    with mock.patch.dict(os.environ, {}, clear=True):
        assert not LSFEnvironment.detect()

    with mock.patch.dict(
        os.environ,
        {
            "LSB_DJOB_RANKFILE": "",
            "LSB_JOBID": "",
            "JSM_NAMESPACE_SIZE": "",
            "JSM_NAMESPACE_LOCAL_RANK": "",
        },
    ):
        assert LSFEnvironment.detect()
