FactStore.h

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#pragma once
#include "common/Export.h"
 
#include "common/Result.h"
#include "common/Value.h"
#include "decision/Condition.h"
 
#include <cstdint>
#include <optional>
#include <string>
#include <string_view>
#include <unordered_map>
#include <vector>
 
namespace eve::emergence {
 
enum class FactDomain : std::uint8_t {
    Value,
    Tag,
    Attribute,
    Resource,
    State,
    Authority,
    Policy,
};
 
enum class FactChange : std::uint8_t { Unchanged = 0, Changed = 1 };
 
[[nodiscard]] EVENGINE_API_FOUNDATION std::string makeFactKey(FactDomain domain, std::string_view name);
 
[[nodiscard]] EVENGINE_API_FOUNDATION eve::Result<std::pair<FactDomain, std::string>> parseFactKey(
    std::string_view key);
 
class EVENGINE_API_FOUNDATION FactStore final : public decision::EvaluationContext {
public:
    void clear();
 
    [[nodiscard]] FactChange setValue(std::string key, eve::Value value);
    [[nodiscard]] FactChange setTag(std::string tag, bool present);
    [[nodiscard]] FactChange setAttribute(std::string key, eve::Value value);
    [[nodiscard]] FactChange setResource(std::string key, eve::Value value);
    [[nodiscard]] FactChange setState(std::string key, eve::Value value);
    [[nodiscard]] FactChange setAuthority(std::string scope, bool granted);
    [[nodiscard]] FactChange setPolicy(std::string name, decision::ConditionResult result);
 
    [[nodiscard]] FactChange clearValue(std::string_view key);
    [[nodiscard]] FactChange clearTag(std::string_view tag);
 
    [[nodiscard]] std::optional<eve::Value>                value(std::string_view key) const override;
    [[nodiscard]] std::optional<bool>                      hasTag(std::string_view tag) const override;
    [[nodiscard]] std::optional<eve::Value>                attribute(std::string_view key) const override;
    [[nodiscard]] std::optional<eve::Value>                resource(std::string_view key) const override;
    [[nodiscard]] std::optional<eve::Value>                state(std::string_view key) const override;
    [[nodiscard]] std::optional<bool>                      authority(std::string_view scope) const override;
    [[nodiscard]] std::optional<decision::ConditionResult> policy(std::string_view  name,
                                                                  const eve::Value& arguments) const override;
 
    [[nodiscard]] std::string snapshotJson() const;
    [[nodiscard]] eve::Result<void> restoreJson(std::string_view json);
 
    [[nodiscard]] int valueCount() const noexcept { return static_cast<int>(values_.size()); }
 
private:
    template <class Map, class T>
    static FactChange assign(Map& map, std::string key, T value);
 
    std::unordered_map<std::string, eve::Value>                values_;
    std::unordered_map<std::string, bool>                      tags_;
    std::unordered_map<std::string, eve::Value>                attributes_;
    std::unordered_map<std::string, eve::Value>                resources_;
    std::unordered_map<std::string, eve::Value>                states_;
    std::unordered_map<std::string, bool>                      authorities_;
    std::unordered_map<std::string, decision::ConditionResult> policies_;
};
 
}  // namespace eve::emergence