//! Command that initializes the node by importing a chain from a file.

use crate::{
    args::{
        utils::{chain_help, genesis_value_parser, SUPPORTED_CHAINS},
        DatabaseArgs,
    },
    dirs::{DataDirPath, MaybePlatformPath},
    version::SHORT_VERSION,
};
use clap::Parser;
use eyre::Context;
use futures::{Stream, StreamExt};
use reth_beacon_consensus::BeaconConsensus;
use reth_config::Config;
use reth_db::{database::Database, init_db};
use reth_downloaders::{
    bodies::bodies::BodiesDownloaderBuilder,
    file_client::{ChunkedFileReader, FileClient, DEFAULT_BYTE_LEN_CHUNK_CHAIN_FILE},
    headers::reverse_headers::ReverseHeadersDownloaderBuilder,
};
use reth_interfaces::{
    consensus::Consensus,
    p2p::{
        bodies::downloader::BodyDownloader,
        headers::downloader::{HeaderDownloader, SyncTarget},
    },
};
use reth_node_core::{events::node::NodeEvent, init::init_genesis};
use reth_node_ethereum::EthEvmConfig;
use reth_primitives::{stage::StageId, ChainSpec, PruneModes, B256, OP_RETH_MAINNET_BELOW_BEDROCK};
use reth_provider::{HeaderSyncMode, ProviderFactory, StageCheckpointReader};
use reth_stages::{
    prelude::*,
    stages::{ExecutionStage, ExecutionStageThresholds, SenderRecoveryStage},
};
use reth_static_file::StaticFileProducer;
use std::{path::PathBuf, sync::Arc};
use tokio::sync::watch;
use tracing::{debug, info};

/// Syncs RLP encoded blocks from a file.
#[derive(Debug, Parser)]
pub struct ImportCommand {
    /// The path to the configuration file to use.
    #[arg(long, value_name = "FILE", verbatim_doc_comment)]
    config: Option<PathBuf>,

    /// The path to the data dir for all reth files and subdirectories.
    ///
    /// Defaults to the OS-specific data directory:
    ///
    /// - Linux: `$XDG_DATA_HOME/reth/` or `$HOME/.local/share/reth/`
    /// - Windows: `{FOLDERID_RoamingAppData}/reth/`
    /// - macOS: `$HOME/Library/Application Support/reth/`
    #[arg(long, value_name = "DATA_DIR", verbatim_doc_comment, default_value_t)]
    datadir: MaybePlatformPath<DataDirPath>,

    /// The chain this node is running.
    ///
    /// Possible values are either a built-in chain or the path to a chain specification file.
    #[arg(
        long,
        value_name = "CHAIN_OR_PATH",
        long_help = chain_help(),
        default_value = SUPPORTED_CHAINS[0],
        value_parser = genesis_value_parser
    )]
    chain: Arc<ChainSpec>,

    /// Disables execution stage.
    #[arg(long, verbatim_doc_comment)]
    disable_execution: bool,

    /// Import OP Mainnet chain below Bedrock. Caution! Flag must be set as env var, since the env
    /// var is read by another process too, in order to make below Bedrock import work.
    #[arg(long, verbatim_doc_comment, env = OP_RETH_MAINNET_BELOW_BEDROCK)]
    op_mainnet_below_bedrock: bool,

    /// Chunk byte length.
    #[arg(long, value_name = "CHUNK_LEN", verbatim_doc_comment)]
    chunk_len: Option<u64>,

    #[command(flatten)]
    db: DatabaseArgs,

    /// The path to a block file for import.
    ///
    /// The online stages (headers and bodies) are replaced by a file import, after which the
    /// remaining stages are executed.
    #[arg(value_name = "IMPORT_PATH", verbatim_doc_comment)]
    path: PathBuf,
}

impl ImportCommand {
    /// Execute `import` command
    pub async fn execute(mut self) -> eyre::Result<()> {
        info!(target: "reth::cli", "reth {} starting", SHORT_VERSION);

        if self.op_mainnet_below_bedrock {
            self.disable_execution = true;
            debug!(target: "reth::cli", "Importing OP mainnet below bedrock");
        }

        if self.disable_execution {
            debug!(target: "reth::cli", "Execution stage disabled");
        }

        debug!(target: "reth::cli",
            chunk_byte_len=self.chunk_len.unwrap_or(DEFAULT_BYTE_LEN_CHUNK_CHAIN_FILE), "Chunking chain import"
        );

        // add network name to data dir
        let data_dir = self.datadir.unwrap_or_chain_default(self.chain.chain);
        let config_path = self.config.clone().unwrap_or_else(|| data_dir.config_path());

        let config: Config = self.load_config(config_path.clone())?;
        info!(target: "reth::cli", path = ?config_path, "Configuration loaded");

        let db_path = data_dir.db_path();

        info!(target: "reth::cli", path = ?db_path, "Opening database");
        let db = Arc::new(init_db(db_path, self.db.database_args())?);
        info!(target: "reth::cli", "Database opened");
        let provider_factory =
            ProviderFactory::new(db.clone(), self.chain.clone(), data_dir.static_files_path())?;

        debug!(target: "reth::cli", chain=%self.chain.chain, genesis=?self.chain.genesis_hash(), "Initializing genesis");

        init_genesis(provider_factory.clone())?;

        let consensus = Arc::new(BeaconConsensus::new(self.chain.clone()));
        info!(target: "reth::cli", "Consensus engine initialized");

        // open file
        let mut reader = ChunkedFileReader::new(&self.path, self.chunk_len).await?;

        while let Some(file_client) = reader.next_chunk().await? {
            // create a new FileClient from chunk read from file
            info!(target: "reth::cli",
                "Importing chain file chunk"
            );

            // override the tip
            let tip = file_client.tip().expect("file client has no tip");
            info!(target: "reth::cli", "Chain file chunk read");

            let (mut pipeline, events) = self
                .build_import_pipeline(
                    &config,
                    provider_factory.clone(),
                    &consensus,
                    Arc::new(file_client),
                    StaticFileProducer::new(
                        provider_factory.clone(),
                        provider_factory.static_file_provider(),
                        PruneModes::default(),
                    ),
                    self.disable_execution,
                )
                .await?;

            // override the tip
            pipeline.set_tip(tip);
            debug!(target: "reth::cli", ?tip, "Tip manually set");

            let provider = provider_factory.provider()?;

            let latest_block_number =
                provider.get_stage_checkpoint(StageId::Finish)?.map(|ch| ch.block_number);
            tokio::spawn(reth_node_core::events::node::handle_events(
                None,
                latest_block_number,
                events,
                db.clone(),
            ));

            // Run pipeline
            info!(target: "reth::cli", "Starting sync pipeline");
            tokio::select! {
                res = pipeline.run() => res?,
                _ = tokio::signal::ctrl_c() => {},
            }
        }

        info!(target: "reth::cli", "Chain file imported");
        Ok(())
    }

    async fn build_import_pipeline<DB, C>(
        &self,
        config: &Config,
        provider_factory: ProviderFactory<DB>,
        consensus: &Arc<C>,
        file_client: Arc<FileClient>,
        static_file_producer: StaticFileProducer<DB>,
        disable_execution: bool,
    ) -> eyre::Result<(Pipeline<DB>, impl Stream<Item = NodeEvent>)>
    where
        DB: Database + Clone + Unpin + 'static,
        C: Consensus + 'static,
    {
        if !file_client.has_canonical_blocks() {
            eyre::bail!("unable to import non canonical blocks");
        }

        let mut header_downloader = ReverseHeadersDownloaderBuilder::new(config.stages.headers)
            .build(file_client.clone(), consensus.clone())
            .into_task();
        header_downloader.update_local_head(file_client.start_header().unwrap());
        header_downloader.update_sync_target(SyncTarget::Tip(file_client.tip().unwrap()));

        let mut body_downloader = BodiesDownloaderBuilder::new(config.stages.bodies)
            .build(file_client.clone(), consensus.clone(), provider_factory.clone())
            .into_task();
        body_downloader
            .set_download_range(file_client.min_block().unwrap()..=file_client.max_block().unwrap())
            .expect("failed to set download range");

        let (tip_tx, tip_rx) = watch::channel(B256::ZERO);
        let factory =
            reth_revm::EvmProcessorFactory::new(self.chain.clone(), EthEvmConfig::default());

        let max_block = file_client.max_block().unwrap_or(0);

        let mut pipeline = Pipeline::builder()
            .with_tip_sender(tip_tx)
            // we want to sync all blocks the file client provides or 0 if empty
            .with_max_block(max_block)
            .add_stages(
                DefaultStages::new(
                    provider_factory.clone(),
                    HeaderSyncMode::Tip(tip_rx),
                    consensus.clone(),
                    header_downloader,
                    body_downloader,
                    factory.clone(),
                    config.stages.etl.clone(),
                )
                .set(SenderRecoveryStage {
                    commit_threshold: config.stages.sender_recovery.commit_threshold,
                })
                .set(ExecutionStage::new(
                    factory,
                    ExecutionStageThresholds {
                        max_blocks: config.stages.execution.max_blocks,
                        max_changes: config.stages.execution.max_changes,
                        max_cumulative_gas: config.stages.execution.max_cumulative_gas,
                        max_duration: config.stages.execution.max_duration,
                    },
                    config
                        .stages
                        .merkle
                        .clean_threshold
                        .max(config.stages.account_hashing.clean_threshold)
                        .max(config.stages.storage_hashing.clean_threshold),
                    config.prune.clone().map(|prune| prune.segments).unwrap_or_default(),
                ))
                .disable_if(StageId::Execution, || disable_execution),
            )
            .build(provider_factory, static_file_producer);

        let events = pipeline.events().map(Into::into);

        Ok((pipeline, events))
    }

    /// Loads the reth config
    fn load_config(&self, config_path: PathBuf) -> eyre::Result<Config> {
        confy::load_path::<Config>(config_path.clone())
            .wrap_err_with(|| format!("Could not load config file {config_path:?}"))
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn parse_common_import_command_chain_args() {
        for chain in SUPPORTED_CHAINS {
            let args: ImportCommand = ImportCommand::parse_from(["reth", "--chain", chain, "."]);
            assert_eq!(
                Ok(args.chain.chain),
                chain.parse::<reth_primitives::Chain>(),
                "failed to parse chain {chain}"
            );
        }
    }
}