/**
 * \file imperative/src/impl/interpreter/option_manager.h
 * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
 *
 * Copyright (c) 2014-2020 Megvii Inc. All rights reserved.
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 */

#pragma once

#include <string>
#include <unordered_map>

#include "megbrain/common.h"

namespace mgb::imperative::interpreter::intl {

struct OptionManager {
private:
    std::unordered_map<std::string, size_t*> m_option_map = {};
public:
#define DEF_OPTION(name, env_key, default_value, desc) \
    size_t name = (m_option_map[#name]=&name, get_option_from_env(env_key, default_value));

    // Environ value would be read only when interpreter initializing.
    DEF_OPTION(async_level,             "MEGENGINE_INTERP_ASYNC_LEVEL",     2,
        "config whether raise error exactly when invoking op.\n"
        "level 2: both device and user side errors are async;\n"
        "level 1: user side errors are sync;\n"
        "level 0: both sync.");
    DEF_OPTION(enable_swap,             "MEGENGINE_ENABLE_SWAP",            0, "");
    DEF_OPTION(enable_drop,             "MEGENGINE_ENABLE_DROP",            0, "");
    DEF_OPTION(max_recompute_time,      "MEGENGINE_MAX_RECOMP_TIME",        1, "");
    DEF_OPTION(catch_worker_execption,  "MEGENGINE_CATCH_WORKER_EXEC",      1,
        "catch worker exception if enabled, close it when debugging");
    DEF_OPTION(buffer_length,           "MEGENGINE_COMMAND_BUFFER_LENGTH",  3,
        "set command buffer length.");
    DEF_OPTION(enable_host_compute,     "MEGENGINE_HOST_COMPUTE",           1,
        "enable host compute, thus computation may be done in host event if it's device is gpu.");
    DEF_OPTION(enable_dtr_auto_drop,    "MEGENGINE_DTR_AUTO_DROP",          0, "");
    DEF_OPTION(dtr_eviction_threshold,  "MEGENGINE_DTR_EVICTION_THRESHOLD", 0,
        "auto drop will start whenever gpu memory usage exceeds this value.");
    DEF_OPTION(dtr_evictee_minimum_size, "MEGENGINE_DTR_EVICTEE_MINIMUM_SIZE", 1048576,
        "the minimum memory value of a tensor added to the candidate set");
    DEF_OPTION(record_computing_path,   "MEGENGINE_RECORD_COMPUTING_PATH",  0, "");

#undef DEF_OPTION

    void set_option(const std::string& name, size_t value) {
        *m_option_map[name] = value;
    }

    size_t get_option(const std::string& name) const {
        return *m_option_map.at(name);
    }

    static size_t get_option_from_env(const std::string& name, size_t default_value) {
        if (const char* env_val = MGB_GETENV(name.c_str())) {
            sscanf(env_val, "%zu", &default_value);
        }
        return default_value;
    }
};

}