//! Command for debugging in-memory merkle trie calculation.

use crate::{
    args::NetworkArgs,
    utils::{get_single_body, get_single_header},
};
use backon::{ConstantBuilder, Retryable};
use clap::Parser;
use reth_chainspec::ChainSpec;
use reth_cli::chainspec::ChainSpecParser;
use reth_cli_commands::common::{AccessRights, Environment, EnvironmentArgs};
use reth_cli_runner::CliContext;
use reth_cli_util::get_secret_key;
use reth_config::Config;
use reth_errors::BlockValidationError;
use reth_evm::execute::{BlockExecutorProvider, Executor};
use reth_execution_types::ExecutionOutcome;
use reth_network::{BlockDownloaderProvider, NetworkHandle};
use reth_network_api::NetworkInfo;
use reth_node_api::{NodeTypesWithDB, NodeTypesWithEngine};
use reth_node_ethereum::EthExecutorProvider;
use reth_primitives::BlockHashOrNumber;
use reth_provider::{
    writer::UnifiedStorageWriter, AccountExtReader, ChainSpecProvider, HashingWriter,
    HeaderProvider, LatestStateProviderRef, OriginalValuesKnown, ProviderFactory,
    StageCheckpointReader, StateWriter, StaticFileProviderFactory, StorageReader,
};
use reth_revm::database::StateProviderDatabase;
use reth_stages::StageId;
use reth_tasks::TaskExecutor;
use reth_trie::StateRoot;
use reth_trie_db::DatabaseStateRoot;
use std::{path::PathBuf, sync::Arc};
use tracing::*;

/// `reth debug in-memory-merkle` command
/// This debug routine requires that the node is positioned at the block before the target.
/// The script will then download the block from p2p network and attempt to calculate and verify
/// merkle root for it.
#[derive(Debug, Parser)]
pub struct Command<C: ChainSpecParser> {
    #[command(flatten)]
    env: EnvironmentArgs<C>,

    #[command(flatten)]
    network: NetworkArgs,

    /// The number of retries per request
    #[arg(long, default_value = "5")]
    retries: usize,

    /// The depth after which we should start comparing branch nodes
    #[arg(long)]
    skip_node_depth: Option<usize>,
}

impl<C: ChainSpecParser<ChainSpec = ChainSpec>> Command<C> {
    async fn build_network<N: NodeTypesWithDB<ChainSpec = C::ChainSpec>>(
        &self,
        config: &Config,
        task_executor: TaskExecutor,
        provider_factory: ProviderFactory<N>,
        network_secret_path: PathBuf,
        default_peers_path: PathBuf,
    ) -> eyre::Result<NetworkHandle> {
        let secret_key = get_secret_key(&network_secret_path)?;
        let network = self
            .network
            .network_config(config, provider_factory.chain_spec(), secret_key, default_peers_path)
            .with_task_executor(Box::new(task_executor))
            .build(provider_factory)
            .start_network()
            .await?;
        info!(target: "reth::cli", peer_id = %network.peer_id(), local_addr = %network.local_addr(), "Connected to P2P network");
        debug!(target: "reth::cli", peer_id = ?network.peer_id(), "Full peer ID");
        Ok(network)
    }

    /// Execute `debug in-memory-merkle` command
    pub async fn execute<N: NodeTypesWithEngine<ChainSpec = C::ChainSpec>>(
        self,
        ctx: CliContext,
    ) -> eyre::Result<()> {
        let Environment { provider_factory, config, data_dir } =
            self.env.init::<N>(AccessRights::RW)?;

        let provider = provider_factory.provider()?;

        // Look up merkle checkpoint
        let merkle_checkpoint = provider
            .get_stage_checkpoint(StageId::MerkleExecute)?
            .expect("merkle checkpoint exists");

        let merkle_block_number = merkle_checkpoint.block_number;

        // Configure and build network
        let network_secret_path =
            self.network.p2p_secret_key.clone().unwrap_or_else(|| data_dir.p2p_secret());
        let network = self
            .build_network(
                &config,
                ctx.task_executor.clone(),
                provider_factory.clone(),
                network_secret_path,
                data_dir.known_peers(),
            )
            .await?;

        let target_block_number = merkle_block_number + 1;

        info!(target: "reth::cli", target_block_number, "Downloading full block");
        let fetch_client = network.fetch_client().await?;

        let retries = self.retries.max(1);
        let backoff = ConstantBuilder::default().with_max_times(retries);

        let client = fetch_client.clone();
        let header = (move || {
            get_single_header(client.clone(), BlockHashOrNumber::Number(target_block_number))
        })
        .retry(&backoff)
        .notify(|err, _| warn!(target: "reth::cli", "Error requesting header: {err}. Retrying..."))
        .await?;

        let client = fetch_client.clone();
        let chain = provider_factory.chain_spec();
        let block = (move || get_single_body(client.clone(), Arc::clone(&chain), header.clone()))
            .retry(&backoff)
            .notify(
                |err, _| warn!(target: "reth::cli", "Error requesting body: {err}. Retrying..."),
            )
            .await?;

        let db = StateProviderDatabase::new(LatestStateProviderRef::new(
            provider.tx_ref(),
            provider_factory.static_file_provider(),
        ));

        let executor = EthExecutorProvider::ethereum(provider_factory.chain_spec()).executor(db);

        let merkle_block_td =
            provider.header_td_by_number(merkle_block_number)?.unwrap_or_default();
        let block_execution_output = executor.execute(
            (
                &block
                    .clone()
                    .unseal()
                    .with_recovered_senders()
                    .ok_or(BlockValidationError::SenderRecoveryError)?,
                merkle_block_td + block.difficulty,
            )
                .into(),
        )?;
        let execution_outcome = ExecutionOutcome::from((block_execution_output, block.number));

        // Unpacked `BundleState::state_root_slow` function
        let (in_memory_state_root, in_memory_updates) = StateRoot::overlay_root_with_updates(
            provider.tx_ref(),
            execution_outcome.hash_state_slow(),
        )?;

        if in_memory_state_root == block.state_root {
            info!(target: "reth::cli", state_root = ?in_memory_state_root, "Computed in-memory state root matches");
            return Ok(())
        }

        let provider_rw = provider_factory.provider_rw()?;

        // Insert block, state and hashes
        provider_rw.insert_historical_block(
            block
                .clone()
                .try_seal_with_senders()
                .map_err(|_| BlockValidationError::SenderRecoveryError)?,
        )?;
        let mut storage_writer = UnifiedStorageWriter::from_database(&provider_rw);
        storage_writer.write_to_storage(execution_outcome, OriginalValuesKnown::No)?;
        let storage_lists = provider_rw.changed_storages_with_range(block.number..=block.number)?;
        let storages = provider_rw.plain_state_storages(storage_lists)?;
        provider_rw.insert_storage_for_hashing(storages)?;
        let account_lists = provider_rw.changed_accounts_with_range(block.number..=block.number)?;
        let accounts = provider_rw.basic_accounts(account_lists)?;
        provider_rw.insert_account_for_hashing(accounts)?;

        let (state_root, incremental_trie_updates) = StateRoot::incremental_root_with_updates(
            provider_rw.tx_ref(),
            block.number..=block.number,
        )?;
        if state_root != block.state_root {
            eyre::bail!(
                "Computed incremental state root mismatch. Expected: {:?}. Got: {:?}",
                block.state_root,
                state_root
            );
        }

        // Compare updates
        let mut in_mem_mismatched = Vec::new();
        let mut incremental_mismatched = Vec::new();
        let mut in_mem_updates_iter = in_memory_updates.account_nodes_ref().iter().peekable();
        let mut incremental_updates_iter =
            incremental_trie_updates.account_nodes_ref().iter().peekable();

        while in_mem_updates_iter.peek().is_some() || incremental_updates_iter.peek().is_some() {
            match (in_mem_updates_iter.next(), incremental_updates_iter.next()) {
                (Some(in_mem), Some(incr)) => {
                    similar_asserts::assert_eq!(in_mem.0, incr.0, "Nibbles don't match");
                    if in_mem.1 != incr.1 &&
                        in_mem.0.len() > self.skip_node_depth.unwrap_or_default()
                    {
                        in_mem_mismatched.push(in_mem);
                        incremental_mismatched.push(incr);
                    }
                }
                (Some(in_mem), None) => {
                    warn!(target: "reth::cli", next = ?in_mem, "In-memory trie updates have more entries");
                }
                (None, Some(incr)) => {
                    tracing::warn!(target: "reth::cli", next = ?incr, "Incremental trie updates have more entries");
                }
                (None, None) => {
                    tracing::info!(target: "reth::cli", "Exhausted all trie updates entries");
                }
            }
        }

        similar_asserts::assert_eq!(
            incremental_mismatched,
            in_mem_mismatched,
            "Mismatched trie updates"
        );

        // Drop without committing.
        drop(provider_rw);

        Ok(())
    }
}