#include <mbgl/tile/tile_cache.hpp>
#include <mbgl/tile/tile_data.hpp>

#include <cassert>

namespace mbgl {

void TileCache::setSize(size_t size_) {
    size = size_;

    while (orderedKeys.size() > size) {
        auto key = orderedKeys.front();
        orderedKeys.pop_front();
        tiles.erase(key);
    }

    assert(orderedKeys.size() <= size);

    tiles.reserve(size);
}

void TileCache::add(uint64_t key, std::shared_ptr<TileData> data) {

    // insert new or query existing data
    if (tiles.emplace(key, data).second) {
        // remove existing data key
        orderedKeys.remove(key);
    }

    // (re-)insert data key as newest
    orderedKeys.push_back(key);

    // purge oldest key/data if necessary
    if (orderedKeys.size() > size) {
        get(orderedKeys.front());
    }

    assert(orderedKeys.size() <= size);
};

std::shared_ptr<TileData> TileCache::get(uint64_t key) {

    std::shared_ptr<TileData> data;

    auto it = tiles.find(key);
    if (it != tiles.end()) {
        data = it->second;
        tiles.erase(it);
        orderedKeys.remove(key);
        assert(data->isReady());
    }

    return data;
};

bool TileCache::has(uint64_t key) {
    return tiles.find(key) != tiles.end();
}

void TileCache::clear() {
    orderedKeys.clear();
    tiles.clear();
}

} // namespace mbgl