// See the file "COPYING" in the main distribution directory for copyright.

#pragma once

#include <netdb.h>
#include <sys/socket.h>
#include <cstdint>
#include <string>

#include "zeek/IPAddr.h"
#include "zeek/Val.h"

namespace zeek::detail {

class DNS_Mapping;
using DNS_MappingPtr = std::shared_ptr<DNS_Mapping>;

class DNS_Mapping {
public:
    DNS_Mapping() = delete;
    DNS_Mapping(std::string host, struct hostent* h, uint32_t ttl, int type);
    DNS_Mapping(const IPAddr& addr, struct hostent* h, uint32_t ttl);
    DNS_Mapping(FILE* f);

    bool NoMapping() const { return no_mapping; }
    bool InitFailed() const { return init_failed; }

    ~DNS_Mapping() = default;

    // Returns nil if this was an address request.
    // TODO: fix this an uses of this to just return the empty string
    const char* ReqHost() const { return req_host.empty() ? nullptr : req_host.c_str(); }
    const IPAddr& ReqAddr() const { return req_addr; }
    std::string ReqStr() const { return req_host.empty() ? req_addr.AsString() : req_host; }
    int ReqType() const { return req_type; }

    ListValPtr Addrs();
    TableValPtr AddrsSet(); // addresses returned as a set
    StringValPtr Host();

    double CreationTime() const { return creation_time; }
    uint32_t TTL() const { return req_ttl; }

    void Save(FILE* f) const;

    bool Failed() const { return failed; }
    bool Valid() const { return ! failed; }

    bool Expired() const { return util::current_time() > (creation_time + req_ttl); }

    void Merge(const DNS_MappingPtr& other);

    static void InitializeCache(FILE* f);
    static bool ValidateCacheVersion(FILE* f);

protected:
    friend class DNS_Mgr;

    void Init(struct hostent* h);
    void Clear();

    std::string req_host;
    IPAddr req_addr;
    uint32_t req_ttl = 0;
    int req_type = 0;

    // This class supports multiple names per address, but we only store one of them.
    std::vector<std::string> names;
    StringValPtr host_val;

    std::vector<IPAddr> addrs;
    ListValPtr addrs_val;

    double creation_time = 0.0;
    bool no_mapping = false; // when initializing from a file, immediately hit EOF
    bool init_failed = false;
    bool failed = false;
};

} // namespace zeek::detail