// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Dim Himro

#include "decode_database.h"
#include <stdexcept>
#include <unordered_set>
#include <utility>

DecodeDatabase::Storage::Storage(std::vector<DecodeFrame> definitions)
    : frames(std::move(definitions)) {
    frameIndexByKey.reserve(frames.size());
    for (std::size_t index = 0U; index < frames.size(); ++index) {
        const DecodeFrame &frame = frames[index];
        if (!frameIndexByKey.emplace(frame.GetKey(), index).second)
            throw std::invalid_argument("Duplicate runtime frame key");
        std::unordered_set<std::string> names;
        for (const DecodeSignal &signal: frame.signals) {
            if (!names.insert(signal.name).second)
                throw std::invalid_argument("Duplicate runtime signal key");
        }
    }
}

DecodeDatabase::DecodeDatabase(std::vector<DecodeFrame> frames)
    : storage(std::make_shared<const Storage>(std::move(frames))) {
}

const std::vector<DecodeFrame> &DecodeDatabase::GetFrames() const {
    static const std::vector<DecodeFrame> empty;
    return storage ? storage->frames : empty;
}

std::shared_ptr<const DecodeFrame> DecodeDatabase::FindFrame(const FrameKey &key) const {
    if (!storage)
        return nullptr;
    const std::unordered_map<FrameKey, std::size_t, FrameKeyHasher>::const_iterator it =
            storage->frameIndexByKey.find(key);
    if (it == storage->frameIndexByKey.end())
        return nullptr;
    return std::shared_ptr<const DecodeFrame>(storage, &storage->frames[it->second]);
}

std::shared_ptr<const DecodeSignal> DecodeDatabase::FindSignal(const SignalKey &key) const {
    const std::shared_ptr<const DecodeFrame> frame = FindFrame(key.frame);
    if (!frame)
        return nullptr;
    for (const DecodeSignal &signal: frame->signals) {
        if (signal.name == key.name)
            return std::shared_ptr<const DecodeSignal>(frame, &signal);
    }
    return nullptr;
}