/**
 * Copyright (c) 2021-2022 Huawei Device Co., Ltd.
 * 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.
 */

#include "pgo.h"
#include "utils/logger.h"

namespace panda::panda_file::pgo {

/* static */
std::string ProfileOptimizer::GetNameInfo(const std::unique_ptr<BaseItem> &item)
{
    std::string identity;
    if (item->GetName() == CLASS_ITEM) {
        identity = static_cast<ClassItem *>(item.get())->GetNameItem()->GetData();
        ASSERT(identity.find('L') == 0);                        // the first character must be 'L'
        // must end with ";\0",2 indicates the end mark of the count
        ASSERT(identity.find(";\0") == identity.length() - 2);
        // remove 'L' and ";\0",3 indicates the number of characters that need to be removed
        identity = identity.substr(1, identity.length() - 3);
        std::replace(identity.begin(), identity.end(), '/', '.');
    } else if (item->GetName() == STRING_ITEM) {
        identity = static_cast<StringItem *>(item.get())->GetData();
        ASSERT(identity.find('\0') == identity.length() - 1);  // must end with '\0'
        identity.pop_back();                                   // remove '\0'
    } else {
        UNREACHABLE();
    }
    return identity;
}

void ProfileOptimizer::MarkProfileItem(std::unique_ptr<BaseItem> &item, bool set_pgo) const
{
    auto inc = static_cast<uint32_t>(set_pgo);
    if (item->GetName() == CLASS_ITEM) {
        item->SetPGORank(PGO_CLASS_DEFAULT_COUNT + inc);
    } else if (item->GetName() == STRING_ITEM) {
        item->SetPGORank(PGO_STRING_DEFAULT_COUNT + inc);
    } else if (item->GetName() == CODE_ITEM) {
        item->SetPGORank(PGO_CODE_DEFAULT_COUNT + inc);
    } else {
        UNREACHABLE();
    }
}

bool ProfileOptimizer::ParseProfileData()
{
    std::ifstream file;
    file.open(profile_file_path_, std::ios::in);
    if (!file.is_open()) {
        LOG(ERROR, PANDAFILE) << "failed to open pgo files: " << profile_file_path_;
        return false;
    }
    std::string str_line;
    while (std::getline(file, str_line)) {
        if (str_line.empty()) {
            continue;
        }
        auto comma_pos = str_line.find(':');
        if (comma_pos == std::string::npos) {
            continue;
        }
        auto item_type = str_line.substr(0, comma_pos);
        auto str = str_line.substr(comma_pos + 1);
        profile_data_.emplace_back(item_type, str);
    }

    return true;
}

static bool cmp(const std::unique_ptr<BaseItem> &item1, const std::unique_ptr<BaseItem> &item2)
{
    if (item1->GetPGORank() == item2->GetPGORank()) {
        return item1->GetOriginalRank() < item2->GetOriginalRank();
    }
    if ((item1->GetName() != CODE_ITEM && item2->GetName() != CODE_ITEM) ||
        (item1->GetName() == CODE_ITEM && item2->GetName() == CODE_ITEM)) {
        return item1->GetPGORank() > item2->GetPGORank();
    }
    // code items will depends on the layout of string and literal item, so put it on the end
    return item1->GetName() != CODE_ITEM;
}

void ProfileOptimizer::ProfileGuidedRelayout(std::list<std::unique_ptr<BaseItem>> &items)
{
    ParseProfileData();
    uint32_t original_rank = 0;
    for (auto &item : items) {
        item->SetOriginalRank(original_rank++);
        if (!item->NeedsEmit()) {
            continue;
        }
        auto type_name = item->GetName();
        if (type_name != CLASS_ITEM && type_name != STRING_ITEM && type_name != CODE_ITEM) {
            continue;
        }

        MarkProfileItem(item, false);

        auto finder = [&item](const std::pair<std::string, std::string> &p) {
            if (p.first != item->GetName()) {
                return false;
            }
            if (item->GetName() != CODE_ITEM) {
                return p.second == GetNameInfo(item);
            }
            // CodeItem can be shared between multiple methods, so we need to check all these methods
            auto method_names = static_cast<CodeItem *>(item.get())->GetMethodNames();
            return std::find(method_names.begin(), method_names.end(), p.second) != method_names.end();
        };
        if (std::find_if(profile_data_.begin(), profile_data_.end(), finder) != profile_data_.end()) {
            MarkProfileItem(item, true);
        }
    }

    items.sort(cmp);
}

}  // namespace panda::panda_file::pgo