// Copyright (c) 2011-2021 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <blockstorage.h>

#include <chainparams.h>
#include <fs.h>
#include <shutdown.h>
#include <util/system.h>
#include <validation.h>

struct CImportingNow {
    CImportingNow()
    {
        assert(fImporting == false);
        fImporting = true;
    }

    ~CImportingNow()
    {
        assert(fImporting == true);
        fImporting = false;
    }
};

void ThreadImport(ChainstateManager& chainman, std::vector<fs::path> vImportFiles, const ArgsManager& args)
{
    const CChainParams& chainparams = Params();
    ScheduleBatchPriority();

    {
        CImportingNow imp;

        // -reindex
        if (fReindex) {
            int nFile = 0;
            while (true) {
                FlatFilePos pos(nFile, 0);
                if (!fs::exists(GetBlockPosFilename(pos)))
                    break; // No block files left to reindex
                FILE* file = OpenBlockFile(pos, true);
                if (!file)
                    break; // This error is logged in OpenBlockFile
                LogPrintf("Reindexing block file blk%05u.dat...\n", (unsigned int)nFile);
                ::ChainstateActive().LoadExternalBlockFile(chainparams, file, &pos);
                if (ShutdownRequested()) {
                    LogPrintf("Shutdown requested. Exit %s\n", __func__);
                    return;
                }
                nFile++;
            }
            pblocktree->WriteReindexing(false);
            fReindex = false;
            LogPrintf("Reindexing finished\n");
            // To avoid ending up in a situation without genesis block, re-try initializing (no-op if reindexing worked):
            ::ChainstateActive().LoadGenesisBlock(chainparams);
        }

        // -loadblock=
        for (const fs::path& path : vImportFiles) {
            FILE* file = fsbridge::fopen(path, "rb");
            if (file) {
                LogPrintf("Importing blocks file %s...\n", path.string());
                ::ChainstateActive().LoadExternalBlockFile(chainparams, file);
                if (ShutdownRequested()) {
                    LogPrintf("Shutdown requested. Exit %s\n", __func__);
                    return;
                }
            } else {
                LogPrintf("Warning: Could not open blocks file %s\n", path.string());
            }
        }

        // scan for better chains in the block chain database, that are not yet connected in the active best chain

        // We can't hold cs_main during ActivateBestChain even though we're accessing
        // the chainman unique_ptrs since ABC requires us not to be holding cs_main, so retrieve
        // the relevant pointers before the ABC call.
        for (CChainState* chainstate : WITH_LOCK(::cs_main, return chainman.GetAll())) {
            BlockValidationState state;
            if (!chainstate->ActivateBestChain(state, chainparams, nullptr)) {
                LogPrintf("Failed to connect best block (%s)\n", state.ToString());
                StartShutdown();
                return;
            }
        }

        if (args.GetBoolArg("-stopafterblockimport", DEFAULT_STOPAFTERBLOCKIMPORT)) {
            LogPrintf("Stopping after block import\n");
            StartShutdown();
            return;
        }
    } // End scope of CImportingNow
    chainman.ActiveChainstate().LoadMempool(args);
}