# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
#
# 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 unittest
import paddle
import os
import sys
import pickle
import shlex
import shutil
import inspect
import numpy as np
from collections import OrderedDict
from paddle.distributed.fleet.launch_utils import run_with_coverage
from paddle.distributed.passes.pass_base import PassBase, PassManager


def prepare_python_path_and_return_module(path):
    dirname, filename = os.path.split(path)
    py_suffix = ".py"
    assert filename.endswith(py_suffix), filename

    env_name = 'PYTHONPATH'
    python_path = os.environ.get(env_name, '')
    if python_path:
        paths = [p for p in python_path.split(":") if p]
        if dirname not in paths:
            paths.append(dirname)
        python_path = ":".join(paths)
    else:
        python_path = dirname
    os.environ[env_name] = python_path
    print('GLOG_v=', os.environ.get('GLOG_v', None), flush=1)
    return filename[: -len(py_suffix)]


def remove_path_if_exists(path):
    if not os.path.exists(path):
        return

    if os.path.isfile(path):
        os.remove(path)
    else:
        shutil.rmtree(path)


# NOTE: only support GPU now
class DistPassTestBase(unittest.TestCase):
    def setUp(self):
        paddle.enable_static()
        if paddle.is_compiled_with_cuda():
            paddle.set_flags({'FLAGS_cudnn_deterministic': 1})

        seed = int(os.environ.get('SEED', -1))
        if seed <= 0:
            seed = np.random.randint(low=1, high=1000000, size=[1])[0]
            os.environ['SEED'] = str(seed)
        self.seed = seed
        paddle.seed(self.seed)

        self.rtol = 1e-5
        self.atol = 1e-8
        self.equal_nan = False

        self.init()

    def init(self):
        pass

    def get_model(self, place, **kwargs):
        raise NotImplementedError()

    def apply_passes(self, main_prog, startup_prog):
        raise NotImplementedError()

    def check_main(self, model=None, gpus=None, **kwargs):
        pass_rets = self._distributed_launch(
            model=model, apply_pass=True, gpus=gpus, **kwargs
        )
        no_pass_rets = self._distributed_launch(
            model=model, apply_pass=False, gpus=gpus, **kwargs
        )
        self.check_results(no_pass_rets, pass_rets)

    def check_results(self, no_pass_rets, pass_rets):
        self.assertEqual(len(no_pass_rets), len(pass_rets))
        for no_pass_ret, pass_ret in zip(no_pass_rets, pass_rets):
            self.assertEqual(len(no_pass_ret), len(pass_ret))
            for i, (out_var_no_pass, out_var_pass) in enumerate(
                zip(no_pass_ret, pass_ret)
            ):
                if out_var_no_pass is None:
                    self.assertIsNone(out_var_pass)
                else:
                    np.testing.assert_allclose(
                        out_var_no_pass,
                        out_var_pass,
                        rtol=self.rtol,
                        atol=self.atol,
                        equal_nan=self.equal_nan,
                    )

    @classmethod
    def _to_var_names(cls, names_or_vars):
        if not isinstance(names_or_vars, (list, tuple)):
            names_or_vars = [names_or_vars]
        ret_var_names = []
        for name_or_var in names_or_vars:
            if isinstance(name_or_var, str):
                ret_var_names.append(name_or_var)
            else:
                ret_var_names.append(name_or_var.name)
        return ret_var_names

    def _run_gpu_main(self, model, apply_pass, dump_file, **kwargs):
        gpu_id = int(os.environ.get('FLAGS_selected_gpus', 0))
        place = paddle.CUDAPlace(gpu_id)
        scope = paddle.static.Scope()
        if model is None:
            model = self.get_model
        with paddle.static.program_guard(
            paddle.static.Program(), paddle.static.Program()
        ):
            with paddle.static.scope_guard(scope):
                with paddle.fluid.unique_name.guard():
                    main_prog, startup_prog, inputs, outputs, reader = model(
                        place, **kwargs
                    )
                    inputs = self._to_var_names(inputs)
                    outputs = self._to_var_names(outputs)
                    if apply_pass:
                        self.apply_passes(main_prog, startup_prog)

        all_fetch_values = []
        exe = paddle.static.Executor(place)
        with paddle.static.scope_guard(scope):
            exe.run(startup_prog)
            for batch_id, input_data in enumerate(reader()):
                assert len(input_data) == len(inputs), "{} vs {}".format(
                    len(input_data), len(inputs)
                )
                feed = dict(zip(inputs, input_data))
                fetch_values = exe.run(main_prog, feed=feed, fetch_list=outputs)
                if paddle.distributed.get_rank() == 0:
                    output_dict = OrderedDict(zip(outputs, fetch_values))
                    print('batch {}, outputs {}'.format(batch_id, output_dict))
                all_fetch_values.append(fetch_values)
        with open(dump_file, "wb") as f:
            pickle.dump(all_fetch_values, f)

    @classmethod
    def _get_default_gpu_lists(cls):
        visible_devices = os.getenv("CUDA_VISIBLE_DEVICES")
        if visible_devices is None:
            visible_devices = os.getenv("FLAGS_selected_gpus")

        if visible_devices is None:
            num_gpus = paddle.device.cuda.device_count()
            return list(range(num_gpus))
        else:
            return [
                int(s.strip()) for s in visible_devices.split(",") if s.strip()
            ]

    def _distributed_launch(self, model, apply_pass, gpus=None, **kwargs):
        if gpus is None:
            gpus = self._get_default_gpu_lists()

        num_gpus = len(gpus)
        gpus = ','.join([str(gpu_id) for gpu_id in gpus])

        pid = os.getpid()
        if apply_pass:
            output_dir = "test_with_pass_{}".format(pid)
        else:
            output_dir = "test_without_pass_{}".format(pid)
        remove_path_if_exists(output_dir)
        os.makedirs(output_dir, mode=777)

        input_dump_file = os.path.join(output_dir, 'inputs.bin')
        model_dump_file = os.path.join(output_dir, 'model.bin')

        if os.environ.get("WITH_COVERAGE", "OFF") == "ON":
            run_with_coverage(True)
            coverage_args = ["-m", "coverage", "run", "--branch", "-p"]
        else:
            coverage_args = []

        file_dir = os.path.dirname(os.path.abspath(__file__))

        try:
            with open(input_dump_file, 'wb') as f:
                pickle.dump(kwargs, f)

            if model is not None:
                with open(model_dump_file, 'wb') as f:
                    pickle.dump(model, f)

            cmd = (
                [
                    sys.executable,
                    "-u",
                ]
                + coverage_args
                + [
                    "-m",
                    "launch",
                    "--log_dir",
                    output_dir,
                    "--gpus",
                    gpus,
                    os.path.join(file_dir, "pass_run_main.py"),
                    "--file_path",
                    inspect.getfile(type(self)),
                    "--class_name",
                    type(self).__name__,
                    "--input_file",
                    input_dump_file,
                    "--output_dir",
                    output_dir,
                ]
            )
            if apply_pass:
                cmd += ["--apply_pass"]
            if model is not None:
                cmd += ["--model_file", model_dump_file]
            cmd = [shlex.quote(c) for c in cmd]
            prepare_python_path_and_return_module(__file__)
            exitcode = os.system(' '.join(cmd))
            self.assertEqual(
                exitcode,
                0,
                "Pass test failed with apply_pass = {}, please view log in {}".format(
                    apply_pass, output_dir
                ),
            )

            results = []
            for i in range(num_gpus):
                dump_file = '{0}/{1}.bin'.format(output_dir, i)
                self.assertTrue(
                    os.path.exists(dump_file),
                    "Pass test failed with apply_pass = {}, please view log in {}".format(
                        apply_pass, output_dir
                    ),
                )
                with open(dump_file, "rb") as f:
                    results.append(pickle.load(f))
            return results
        finally:
            if int(os.environ.get("DEBUG", 0)) == 0:
                remove_path_if_exists(output_dir)


class PassConflictChecker(DistPassTestBase):
    def setUp(self):
        os.environ['DEBUG'] = '1'  # to save the debug directory
        super(PassConflictChecker, self).setUp()

    def pass_config(self):
        raise NotImplementedError()

    def apply_passes(self, main_prog, startup_prog):
        passes = self.pass_config()
        if not isinstance(passes, (list, tuple)):
            passes = [passes]
        for p in passes:
            self.assertTrue(isinstance(p, PassBase))

        auto_pass_manager = PassManager(passes, auto_solve_conflict=True)
        new_passes = auto_pass_manager.passes
        self.assertEqual(
            len(passes),
            len(new_passes),
            "After solving conflicts, the left passes are: {}".format(
                auto_pass_manager.names
            ),
        )

        for i, (p1, p2) in enumerate(zip(passes, new_passes)):
            self.assertEqual(
                id(p1),
                id(p2),
                "After solving conflicts, the {}-th pass is different: {} vs {}".format(
                    i, p1.name, p2.name
                ),
            )

        auto_pass_manager.apply([main_prog], [startup_prog])
