#include "lix/libcmd/command.hh"
#include "lix/libmain/shared.hh"
#include "lix/libstore/store-api.hh"
#include "lix/libutil/async.hh"
#include "lix/libutil/thread-pool.hh"
#include "lix/libutil/signals.hh"
#include "sigs.hh"

#include <atomic>
#include <functional>

namespace nix {

struct CmdCopySigs : StorePathsCommand
{
    Strings substituterUris;

    CmdCopySigs()
    {
        addFlag({
            .longName = "substituter",
            .shortName = 's',
            .description = "Copy signatures from the specified store.",
            .labels = {"store-uri"},
            .handler = {[&](std::string s) { substituterUris.push_back(s); }},
        });
    }

    std::string description() override
    {
        return "copy store path signatures from substituters";
    }

    void run(ref<Store> store, StorePaths && storePaths) override
    {
        if (substituterUris.empty())
            throw UsageError("you must specify at least one substituter using '-s'");

        // FIXME: factor out commonality with MixVerify.
        std::vector<ref<Store>> substituters;
        for (auto & s : substituterUris)
            substituters.push_back(aio().blockOn(openStore(s)));

        ThreadPool pool{"CopySigs pool"};

        std::atomic<size_t> added{0};

        auto doPath = [&](AsyncIoRoot & aio, const Path & storePathS) {

            checkInterrupt();

            auto storePath = store->parseStorePath(storePathS);

            auto info = aio.blockOn(store->queryPathInfo(storePath));

            StringSet newSigs;

            for (auto & store2 : substituters) {
                try {
                    auto info2 = aio.blockOn(store2->queryPathInfo(info->path));

                    /* Don't import signatures that don't match this
                       binary. */
                    if (info->narHash != info2->narHash ||
                        info->narSize != info2->narSize ||
                        info->references != info2->references)
                        continue;

                    for (auto & sig : info2->sigs)
                        if (!info->sigs.count(sig))
                            newSigs.insert(sig);
                } catch (InvalidPath &) {
                }
            }

            if (!newSigs.empty()) {
                aio.blockOn(store->addSignatures(storePath, newSigs));
                added += newSigs.size();
            }
        };

        for (auto & storePath : storePaths) {
            pool.enqueueWithAio(
                std::bind(doPath, std::placeholders::_1, store->printStorePath(storePath))
            );
        }

        pool.process();

        printInfo("imported %d signatures", added);
    }
};

struct CmdSign : StorePathsCommand
{
    Path secretKeyFile;

    CmdSign()
    {
        addFlag({
            .longName = "key-file",
            .shortName = 'k',
            .description = "File containing the secret signing key.",
            .labels = {"file"},
            .handler = {&secretKeyFile},
            .completer = completePath
        });
    }

    std::string description() override
    {
        return "sign store paths";
    }

    void run(ref<Store> store, StorePaths && storePaths) override
    {
        if (secretKeyFile.empty())
            throw UsageError("you must specify a secret key file using '-k'");

        SecretKey secretKey(readFile(secretKeyFile));

        ThreadPool pool{"Sign pool"};

        std::atomic<size_t> added{0};

        auto doPath = [&](AsyncIoRoot & aio, const Path & storePathS) {

            checkInterrupt();

            auto storePath = store->parseStorePath(storePathS);

            auto info = aio.blockOn(store->queryPathInfo(storePath));

            auto info2(*info);
            info2.sigs.clear();
            info2.sign(*store, secretKey);
            assert(!info2.sigs.empty());

            if (!info->sigs.count(*info2.sigs.begin())) {
                aio.blockOn(store->addSignatures(storePath, info2.sigs));
                added++;
            }
        };

        for (auto & storePath : storePaths) {
            pool.enqueueWithAio(
                std::bind(doPath, std::placeholders::_1, store->printStorePath(storePath))
            );
        }

        pool.process();

        printInfo("added %d signatures", added);
    }
};

struct CmdKeyGenerateSecret : Command
{
    std::optional<std::string> keyName;

    CmdKeyGenerateSecret()
    {
        addFlag({
            .longName = "key-name",
            .description = "Identifier of the key (e.g. `cache.example.org-1`).",
            .labels = {"name"},
            .handler = {&keyName},
        });
    }

    std::string description() override
    {
        return "generate a secret key for signing store paths";
    }

    std::string doc() override
    {
        return
          #include "key-generate-secret.md"
          ;
    }

    void run() override
    {
        if (!keyName)
            throw UsageError("required argument '--key-name' is missing");

        writeFull(STDOUT_FILENO, SecretKey::generate(*keyName).to_string());
    }
};

struct CmdKeyConvertSecretToPublic : Command
{
    std::string description() override
    {
        return "generate a public key for verifying store paths from a secret key read from standard input";
    }

    std::string doc() override
    {
        return
          #include "key-convert-secret-to-public.md"
          ;
    }

    void run() override
    {
        SecretKey secretKey(drainFD(STDIN_FILENO));
        writeFull(STDOUT_FILENO, secretKey.toPublicKey().to_string());
    }
};

struct CmdKey : MultiCommand
{
    CmdKey()
        : MultiCommand({
            {"generate-secret",
             [](auto & aio) { return make_ref<MixAio<CmdKeyGenerateSecret>>(aio); }},
            {"convert-secret-to-public",
             [](auto & aio) { return make_ref<MixAio<CmdKeyConvertSecretToPublic>>(aio); }},
        })
    {
    }

    std::string description() override
    {
        return "generate and convert Nix signing keys";
    }

    Category category() override { return catUtility; }

    void run() override
    {
        if (!command)
            throw UsageError("'nix key' requires a sub-command.");

        logger->pause();
        command->second->run();
    }
};

void registerNixSigs()
{
    registerCommand2<CmdCopySigs>({"store", "copy-sigs"});
    registerCommand2<CmdSign>({"store", "sign"});
    registerCommand<CmdKey>("key");
}

}
