use {
    crate::{
        blockstore::Blockstore,
        blockstore_processor::{
            self, BlockstoreProcessorError, ProcessOptions, TransactionStatusSender,
        },
        entry_notifier_service::EntryNotifierSender,
        leader_schedule_cache::LeaderScheduleCache,
        use_snapshot_archives_at_startup::{self, UseSnapshotArchivesAtStartup},
    },
    log::*,
    solana_accounts_db::accounts_update_notifier_interface::AccountsUpdateNotifier,
    solana_genesis_config::GenesisConfig,
    solana_runtime::{
        bank_forks::BankForks,
        snapshot_archive_info::{
            FullSnapshotArchiveInfo, IncrementalSnapshotArchiveInfo, SnapshotArchiveInfoGetter,
        },
        snapshot_bank_utils,
        snapshot_config::SnapshotConfig,
        snapshot_hash::{FullSnapshotHash, IncrementalSnapshotHash, StartingSnapshotHashes},
        snapshot_utils,
    },
    std::{
        path::PathBuf,
        result,
        sync::{atomic::AtomicBool, Arc, RwLock},
    },
    thiserror::Error,
};

#[derive(Error, Debug)]
pub enum BankForksUtilsError {
    #[error("accounts path(s) not present when booting from snapshot")]
    AccountPathsNotPresent,

    #[error(
        "failed to load bank: {source}, full snapshot archive: {full_snapshot_archive}, \
         incremental snapshot archive: {incremental_snapshot_archive}"
    )]
    BankFromSnapshotsArchive {
        source: Box<snapshot_utils::SnapshotError>,
        full_snapshot_archive: String,
        incremental_snapshot_archive: String,
    },

    #[error(
        "there is no local state to startup from. Ensure --{flag} is NOT set to \"{value}\" and \
         restart"
    )]
    NoBankSnapshotDirectory { flag: String, value: String },

    #[error("failed to load bank from snapshot '{path}': {source}")]
    BankFromSnapshotsDirectory {
        source: snapshot_utils::SnapshotError,
        path: PathBuf,
    },

    #[error("failed to process blockstore from genesis: {0}")]
    ProcessBlockstoreFromGenesis(#[source] BlockstoreProcessorError),

    #[error("failed to process blockstore from root: {0}")]
    ProcessBlockstoreFromRoot(#[source] BlockstoreProcessorError),
}

pub type LoadResult = result::Result<
    (
        Arc<RwLock<BankForks>>,
        LeaderScheduleCache,
        Option<StartingSnapshotHashes>,
    ),
    BankForksUtilsError,
>;

/// Load the banks via genesis or a snapshot then processes all full blocks in blockstore
///
/// If a snapshot config is given, and a snapshot is found, it will be loaded.  Otherwise, load
/// from genesis.
#[allow(clippy::too_many_arguments)]
pub fn load(
    genesis_config: &GenesisConfig,
    blockstore: &Blockstore,
    account_paths: Vec<PathBuf>,
    snapshot_config: &SnapshotConfig,
    process_options: ProcessOptions,
    transaction_status_sender: Option<&TransactionStatusSender>,
    entry_notification_sender: Option<&EntryNotifierSender>,
    accounts_update_notifier: Option<AccountsUpdateNotifier>,
    exit: Arc<AtomicBool>,
) -> LoadResult {
    let (bank_forks, leader_schedule_cache, starting_snapshot_hashes, ..) = load_bank_forks(
        genesis_config,
        blockstore,
        account_paths,
        snapshot_config,
        &process_options,
        transaction_status_sender,
        entry_notification_sender,
        accounts_update_notifier,
        exit,
    )?;
    blockstore_processor::process_blockstore_from_root(
        blockstore,
        &bank_forks,
        &leader_schedule_cache,
        &process_options,
        transaction_status_sender,
        entry_notification_sender,
        None, // snapshot_controller
    )
    .map_err(BankForksUtilsError::ProcessBlockstoreFromRoot)?;

    Ok((bank_forks, leader_schedule_cache, starting_snapshot_hashes))
}

#[allow(clippy::too_many_arguments)]
pub fn load_bank_forks(
    genesis_config: &GenesisConfig,
    blockstore: &Blockstore,
    account_paths: Vec<PathBuf>,
    snapshot_config: &SnapshotConfig,
    process_options: &ProcessOptions,
    transaction_status_sender: Option<&TransactionStatusSender>,
    entry_notification_sender: Option<&EntryNotifierSender>,
    accounts_update_notifier: Option<AccountsUpdateNotifier>,
    exit: Arc<AtomicBool>,
) -> LoadResult {
    fn get_snapshots_to_load(
        snapshot_config: &SnapshotConfig,
    ) -> Option<(
        FullSnapshotArchiveInfo,
        Option<IncrementalSnapshotArchiveInfo>,
    )> {
        if !snapshot_config.should_load_snapshots() {
            info!("Snapshots disabled; will load from genesis");
            return None;
        };

        let Some(full_snapshot_archive_info) =
            snapshot_utils::get_highest_full_snapshot_archive_info(
                &snapshot_config.full_snapshot_archives_dir,
            )
        else {
            warn!(
                "No snapshot package found in directory: {}; will load from genesis",
                snapshot_config.full_snapshot_archives_dir.display()
            );
            return None;
        };

        let incremental_snapshot_archive_info =
            snapshot_utils::get_highest_incremental_snapshot_archive_info(
                &snapshot_config.incremental_snapshot_archives_dir,
                full_snapshot_archive_info.slot(),
            );

        Some((
            full_snapshot_archive_info,
            incremental_snapshot_archive_info,
        ))
    }

    let (bank_forks, starting_snapshot_hashes) =
        if let Some((full_snapshot_archive_info, incremental_snapshot_archive_info)) =
            get_snapshots_to_load(snapshot_config)
        {
            info!(
                "Initializing bank snapshots dir: {}",
                snapshot_config.bank_snapshots_dir.display()
            );
            std::fs::create_dir_all(&snapshot_config.bank_snapshots_dir)
                .expect("create bank snapshots dir");
            let (bank_forks, starting_snapshot_hashes) = bank_forks_from_snapshot(
                full_snapshot_archive_info,
                incremental_snapshot_archive_info,
                genesis_config,
                account_paths,
                snapshot_config,
                process_options,
                accounts_update_notifier,
                exit,
            )?;
            (bank_forks, Some(starting_snapshot_hashes))
        } else {
            info!("Processing ledger from genesis");
            let bank_forks = blockstore_processor::process_blockstore_for_bank_0(
                genesis_config,
                blockstore,
                account_paths,
                process_options,
                transaction_status_sender,
                entry_notification_sender,
                accounts_update_notifier,
                exit,
            )
            .map_err(BankForksUtilsError::ProcessBlockstoreFromGenesis)?;
            (bank_forks, None)
        };

    let mut leader_schedule_cache =
        LeaderScheduleCache::new_from_bank(&bank_forks.read().unwrap().root_bank());
    if process_options.full_leader_cache {
        leader_schedule_cache.set_max_schedules(usize::MAX);
    }

    if let Some(ref new_hard_forks) = process_options.new_hard_forks {
        let root_bank = bank_forks.read().unwrap().root_bank();
        new_hard_forks
            .iter()
            .for_each(|hard_fork_slot| root_bank.register_hard_fork(*hard_fork_slot));
    }

    Ok((bank_forks, leader_schedule_cache, starting_snapshot_hashes))
}

#[allow(clippy::too_many_arguments)]
fn bank_forks_from_snapshot(
    full_snapshot_archive_info: FullSnapshotArchiveInfo,
    incremental_snapshot_archive_info: Option<IncrementalSnapshotArchiveInfo>,
    genesis_config: &GenesisConfig,
    account_paths: Vec<PathBuf>,
    snapshot_config: &SnapshotConfig,
    process_options: &ProcessOptions,
    accounts_update_notifier: Option<AccountsUpdateNotifier>,
    exit: Arc<AtomicBool>,
) -> Result<(Arc<RwLock<BankForks>>, StartingSnapshotHashes), BankForksUtilsError> {
    // Fail hard here if snapshot fails to load, don't silently continue
    if account_paths.is_empty() {
        return Err(BankForksUtilsError::AccountPathsNotPresent);
    }

    let latest_snapshot_archive_slot = std::cmp::max(
        full_snapshot_archive_info.slot(),
        incremental_snapshot_archive_info
            .as_ref()
            .map(SnapshotArchiveInfoGetter::slot)
            .unwrap_or(0),
    );

    let fastboot_snapshot = match process_options.use_snapshot_archives_at_startup {
        UseSnapshotArchivesAtStartup::Always => None,
        UseSnapshotArchivesAtStartup::Never => {
            let Some(bank_snapshot) =
                snapshot_utils::get_highest_loadable_bank_snapshot(snapshot_config)
            else {
                return Err(BankForksUtilsError::NoBankSnapshotDirectory {
                    flag: use_snapshot_archives_at_startup::cli::LONG_ARG.to_string(),
                    value: UseSnapshotArchivesAtStartup::Never.to_string(),
                });
            };
            // If a newer snapshot archive was downloaded, it is possible that its slot is
            // higher than the local state we will load.  Did the user intend for this?
            if bank_snapshot.slot < latest_snapshot_archive_slot {
                warn!(
                    "Starting up from local state at slot {}, which is *older* than the latest \
                     snapshot archive at slot {}. If this is not desired, change the --{} CLI \
                     option to *not* \"{}\" and restart.",
                    bank_snapshot.slot,
                    latest_snapshot_archive_slot,
                    use_snapshot_archives_at_startup::cli::LONG_ARG,
                    UseSnapshotArchivesAtStartup::Never,
                );
            }
            Some(bank_snapshot)
        }
        UseSnapshotArchivesAtStartup::WhenNewest => {
            snapshot_utils::get_highest_loadable_bank_snapshot(snapshot_config)
                .filter(|bank_snapshot| bank_snapshot.slot >= latest_snapshot_archive_slot)
        }
    };

    let bank = if let Some(fastboot_snapshot) = fastboot_snapshot {
        snapshot_bank_utils::bank_from_snapshot_dir(
            &account_paths,
            &fastboot_snapshot,
            genesis_config,
            &process_options.runtime_config,
            process_options.debug_keys.clone(),
            process_options.limit_load_slot_count_from_snapshot,
            process_options.verify_index,
            process_options.accounts_db_config.clone(),
            accounts_update_notifier,
            exit,
        )
        .map_err(|err| BankForksUtilsError::BankFromSnapshotsDirectory {
            source: err,
            path: fastboot_snapshot.snapshot_path(),
        })?
    } else {
        // Given that we are going to boot from an archive, the append vecs held in the snapshot dirs for fast-boot should
        // be released.  They will be released by the account_background_service anyway.  But in the case of the account_paths
        // using memory-mounted file system, they are not released early enough to give space for the new append-vecs from
        // the archives, causing the out-of-memory problem.  So, purge the snapshot dirs upfront before loading from the archive.
        snapshot_utils::purge_all_bank_snapshots(&snapshot_config.bank_snapshots_dir);

        snapshot_bank_utils::bank_from_snapshot_archives(
            &account_paths,
            &snapshot_config.bank_snapshots_dir,
            &full_snapshot_archive_info,
            incremental_snapshot_archive_info.as_ref(),
            genesis_config,
            &process_options.runtime_config,
            process_options.debug_keys.clone(),
            process_options.limit_load_slot_count_from_snapshot,
            process_options.accounts_db_skip_shrink,
            process_options.accounts_db_force_initial_clean,
            process_options.verify_index,
            process_options.accounts_db_config.clone(),
            accounts_update_notifier,
            exit,
        )
        .map_err(|err| BankForksUtilsError::BankFromSnapshotsArchive {
            source: Box::new(err),
            full_snapshot_archive: full_snapshot_archive_info.path().display().to_string(),
            incremental_snapshot_archive: incremental_snapshot_archive_info
                .as_ref()
                .map(|archive| archive.path().display().to_string())
                .unwrap_or("none".to_string()),
        })?
    };

    // We must inform accounts-db of the latest full snapshot slot, which is used by the background
    // processes to handle zero lamport accounts.  Since we've now successfully loaded the bank
    // from snapshots, this is a good time to do that update.
    // Note, this must only be set if we should generate snapshots, so that we correctly
    // handle (i.e. purge) zero lamport accounts.
    if snapshot_config.should_generate_snapshots() {
        bank.rc
            .accounts
            .accounts_db
            .set_latest_full_snapshot_slot(full_snapshot_archive_info.slot());
    } else {
        assert!(bank
            .rc
            .accounts
            .accounts_db
            .latest_full_snapshot_slot()
            .is_none());
    }

    let full_snapshot_hash = FullSnapshotHash((
        full_snapshot_archive_info.slot(),
        *full_snapshot_archive_info.hash(),
    ));
    let incremental_snapshot_hash =
        incremental_snapshot_archive_info.map(|incremental_snapshot_archive_info| {
            IncrementalSnapshotHash((
                incremental_snapshot_archive_info.slot(),
                *incremental_snapshot_archive_info.hash(),
            ))
        });
    let starting_snapshot_hashes = StartingSnapshotHashes {
        full: full_snapshot_hash,
        incremental: incremental_snapshot_hash,
    };

    Ok((BankForks::new_rw_arc(bank), starting_snapshot_hashes))
}
