// Copyright (C) 2021 The Android Open Source Project
//
// 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 "ShaderCache.h"

#include "aemu/base/MruCache.h"
#include <string.h>
#include <cstdio>

#include <map>
#include <vector>

namespace {
    using BlobCacheType = std::vector<uint8_t>;

    template <class K, class V>
    class CacheObserver : android::base::MruCache<K, V>::MruCacheObserver {
    public:
        int count = 0;
        CacheObserver(android::base::MruCache<K, V>* cacheReference) {
            mCacheRef = cacheReference;
            cacheReference->setObserver(this);
        }

        void cacheChanged() override {
            // TODO: This will dictate when we flatten the cache.
        }

    private:
        android::base::MruCache<K, V>* mCacheRef;
    };

    template <class K, class V>
    class CacheFlattener : public android::base::MruCache<K, V>::CacheFlattener {
        using MruCache = std::map<typename android::base::MruCache<K, V>::template EntryWithSize<K>,
            typename android::base::MruCache<K, V>::template EntryWithSize<V>>;

    public:
        void handleFlatten(MruCache &mCache, void* buf, size_t bufSize) {
            // TODO: This will handle the actual serialization.
        }
    };

    CacheFlattener<BlobCacheType, BlobCacheType> testFlattener;
    // 3200 is ~32MB of shaders, very rough estimate.
    android::base::MruCache<BlobCacheType, BlobCacheType> mruCache(3200, &testFlattener);
    CacheObserver<BlobCacheType, BlobCacheType> sss(&mruCache);
}

void SetBlob(const void* key, EGLsizeiANDROID keySize, const void* value, EGLsizeiANDROID valueSize) {
    std::vector<uint8_t> keyVec(keySize);
    memcpy(keyVec.data(), key, keySize);

    std::vector<uint8_t> valueVec(valueSize);
    memcpy(valueVec.data(), value, valueSize);

    mruCache.put(keyVec, keySize, std::move(valueVec), valueSize);
}

EGLsizeiANDROID GetBlob(const void* key, EGLsizeiANDROID keySize, void* value, EGLsizeiANDROID valueSize) {
    std::vector<uint8_t> keyVec(keySize);
    memcpy(keyVec.data(), key, keySize);

    const std::vector<uint8_t> *result;
    auto found = mruCache.get(keyVec, &result);

    if (!found) {
        return 0;
    }

    if (result->size() <= static_cast<size_t>(valueSize)) {
        memcpy(value, result->data(), result->size());
    }

    // If the size provided was too small, return the right size regardless.
    return result->size();
}