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

#include "zeek/packet_analysis/Dispatcher.h"

#include <algorithm>

#include "zeek/DebugLogger.h"
#include "zeek/Reporter.h"
#include "zeek/packet_analysis/Analyzer.h"

namespace zeek::packet_analysis::detail {

Dispatcher::~Dispatcher() { FreeValues(); }

void Dispatcher::Register(uint64_t identifier, AnalyzerPtr analyzer) {
    // If the table has size 1 and the entry is nullptr, there was nothing added yet. Just add it.
    if ( table.size() == 1 && table[0] == nullptr ) {
        table[0] = std::move(analyzer);
        lowest_identifier = identifier;
        return;
    }

    // If highestIdentifier == identifier, overwrite would happen -> no check needed, will return
    // false
    if ( GetHighestIdentifier() < identifier ) {
        table.resize(table.size() + (identifier - GetHighestIdentifier()), nullptr);
    }
    else if ( identifier < lowest_identifier ) {
        // Lower than the lowest registered identifier. Shift up by lowerBound - identifier
        uint64_t distance = lowest_identifier - identifier;
        table.resize(table.size() + distance, nullptr);

        // Shift values
        for ( ssize_t i = table.size() - 1; i >= 0; i-- ) {
            if ( table[i] != nullptr ) {
                table.at(i + distance) = std::move(table.at(i));
                table.at(i) = nullptr;
            }
        }

        lowest_identifier = identifier;
    }

    int64_t index = identifier - lowest_identifier;
    if ( table[index] != nullptr && table[index] != analyzer )
        reporter->Info("Overwriting packet analyzer mapping %#8" PRIx64 " => %s with %s", index + lowest_identifier,
                       table[index]->GetAnalyzerName(), analyzer->GetAnalyzerName());
    table[index] = std::move(analyzer);
}

const AnalyzerPtr& Dispatcher::Lookup(uint64_t identifier) const {
    int64_t index = identifier - lowest_identifier;
    if ( index >= 0 && index < static_cast<int64_t>(table.size()) )
        return table[index];

    return Analyzer::nil;
}

size_t Dispatcher::Count() const {
    return std::count_if(table.begin(), table.end(), [](AnalyzerPtr a) { return a != nullptr; });
}

void Dispatcher::Clear() {
    FreeValues();
    table.clear();
}

void Dispatcher::FreeValues() {
    for ( auto& current : table )
        current = nullptr;
}

void Dispatcher::DumpDebug() const {
#ifdef DEBUG
    DBG_LOG(DBG_PACKET_ANALYSIS, "Dispatcher elements (used/total): %lu/%lu", Count(), table.size());
    for ( size_t i = 0; i < table.size(); i++ ) {
        if ( table[i] != nullptr )
            DBG_LOG(DBG_PACKET_ANALYSIS, "%#8" PRIx64 " => %s", i + lowest_identifier, table[i]->GetAnalyzerName());
    }
#endif
}

} // namespace zeek::packet_analysis::detail
