//! Configuration files.
use reth_discv4::Discv4Config;
use reth_downloaders::{
    bodies::bodies::BodiesDownloaderBuilder,
    headers::reverse_headers::ReverseHeadersDownloaderBuilder,
};
use reth_network::{NetworkConfigBuilder, PeersConfig, SessionsConfig};
use secp256k1::SecretKey;
use serde::{Deserialize, Serialize};
use std::path::PathBuf;

/// Configuration for the reth node.
#[derive(Debug, Clone, Default, Deserialize, PartialEq, Serialize)]
#[serde(default)]
pub struct Config {
    /// Configuration for each stage in the pipeline.
    // TODO(onbjerg): Can we make this easier to maintain when we add/remove stages?
    pub stages: StageConfig,
    /// Configuration for the discovery service.
    pub peers: PeersConfig,
    /// Configuration for peer sessions.
    pub sessions: SessionsConfig,
}

impl Config {
    /// Initializes network config from read data
    pub fn network_config(
        &self,
        nat_resolution_method: reth_net_nat::NatResolver,
        peers_file: Option<PathBuf>,
        secret_key: SecretKey,
    ) -> NetworkConfigBuilder {
        let peer_config = self
            .peers
            .clone()
            .with_basic_nodes_from_file(peers_file)
            .unwrap_or_else(|_| self.peers.clone());

        let discv4 =
            Discv4Config::builder().external_ip_resolver(Some(nat_resolution_method)).clone();
        NetworkConfigBuilder::new(secret_key)
            .sessions_config(self.sessions.clone())
            .peer_config(peer_config)
            .discovery(discv4)
    }
}

/// Configuration for each stage in the pipeline.
#[derive(Debug, Clone, Default, Deserialize, PartialEq, Serialize)]
#[serde(default)]
pub struct StageConfig {
    /// Header stage configuration.
    pub headers: HeadersConfig,
    /// Total Difficulty stage configuration
    pub total_difficulty: TotalDifficultyConfig,
    /// Body stage configuration.
    pub bodies: BodiesConfig,
    /// Sender Recovery stage configuration.
    pub sender_recovery: SenderRecoveryConfig,
    /// Execution stage configuration.
    pub execution: ExecutionConfig,
    /// Account Hashing stage configuration.
    pub account_hashing: HashingConfig,
    /// Storage Hashing stage configuration.
    pub storage_hashing: HashingConfig,
    /// Merkle stage configuration.
    pub merkle: MerkleConfig,
    /// Transaction Lookup stage configuration.
    pub transaction_lookup: TransactionLookupConfig,
    /// Index Account History stage configuration.
    pub index_account_history: IndexHistoryConfig,
    /// Index Storage History stage configuration.
    pub index_storage_history: IndexHistoryConfig,
}

/// Header stage configuration.
#[derive(Debug, Clone, Copy, Deserialize, PartialEq, Serialize)]
#[serde(default)]
pub struct HeadersConfig {
    /// The maximum number of requests to send concurrently.
    ///
    /// Default: 100
    pub downloader_max_concurrent_requests: usize,
    /// The minimum number of requests to send concurrently.
    ///
    /// Default: 5
    pub downloader_min_concurrent_requests: usize,
    /// Maximum amount of responses to buffer internally.
    /// The response contains multiple headers.
    pub downloader_max_buffered_responses: usize,
    /// The maximum number of headers to request from a peer at a time.
    pub downloader_request_limit: u64,
    /// The maximum number of headers to download before committing progress to the database.
    pub commit_threshold: u64,
}

impl Default for HeadersConfig {
    fn default() -> Self {
        Self {
            commit_threshold: 10_000,
            downloader_request_limit: 1_000,
            downloader_max_concurrent_requests: 100,
            downloader_min_concurrent_requests: 5,
            downloader_max_buffered_responses: 100,
        }
    }
}

impl From<HeadersConfig> for ReverseHeadersDownloaderBuilder {
    fn from(config: HeadersConfig) -> Self {
        ReverseHeadersDownloaderBuilder::default()
            .request_limit(config.downloader_request_limit)
            .min_concurrent_requests(config.downloader_min_concurrent_requests)
            .max_concurrent_requests(config.downloader_max_concurrent_requests)
            .max_buffered_responses(config.downloader_max_buffered_responses)
            .stream_batch_size(config.commit_threshold as usize)
    }
}

/// Total difficulty stage configuration
#[derive(Debug, Clone, Copy, Deserialize, PartialEq, Serialize)]
#[serde(default)]
pub struct TotalDifficultyConfig {
    /// The maximum number of total difficulty entries to sum up before committing progress to the
    /// database.
    pub commit_threshold: u64,
}

impl Default for TotalDifficultyConfig {
    fn default() -> Self {
        Self { commit_threshold: 100_000 }
    }
}

/// Body stage configuration.
#[derive(Debug, Clone, Copy, Deserialize, PartialEq, Serialize)]
#[serde(default)]
pub struct BodiesConfig {
    /// The batch size of non-empty blocks per one request
    ///
    /// Default: 200
    pub downloader_request_limit: u64,
    /// The maximum number of block bodies returned at once from the stream
    ///
    /// Default: 10_000
    pub downloader_stream_batch_size: usize,
    /// Maximum amount of received bodies to buffer internally.
    /// The response contains multiple bodies.
    ///
    /// Default: ~43_000 or 4GB with block size of 100kb
    pub downloader_max_buffered_blocks: usize,
    /// The minimum number of requests to send concurrently.
    ///
    /// Default: 5
    pub downloader_min_concurrent_requests: usize,
    /// The maximum number of requests to send concurrently.
    /// This is equal to the max number of peers.
    ///
    /// Default: 100
    pub downloader_max_concurrent_requests: usize,
}

impl Default for BodiesConfig {
    fn default() -> Self {
        Self {
            downloader_request_limit: 200,
            downloader_stream_batch_size: 10_000,
            // With high block sizes at around 100kb this will be ~4GB of buffered blocks: ~43k
            downloader_max_buffered_blocks: 4 * 1024 * 1024 * 1024 / 100_000,
            downloader_min_concurrent_requests: 5,
            downloader_max_concurrent_requests: 100,
        }
    }
}

impl From<BodiesConfig> for BodiesDownloaderBuilder {
    fn from(config: BodiesConfig) -> Self {
        BodiesDownloaderBuilder::default()
            .with_stream_batch_size(config.downloader_stream_batch_size)
            .with_request_limit(config.downloader_request_limit)
            .with_max_buffered_blocks(config.downloader_max_buffered_blocks)
            .with_concurrent_requests_range(
                config.downloader_min_concurrent_requests..=
                    config.downloader_max_concurrent_requests,
            )
    }
}

/// Sender recovery stage configuration.
#[derive(Debug, Clone, Copy, Deserialize, PartialEq, Eq, Serialize)]
#[serde(default)]
pub struct SenderRecoveryConfig {
    /// The maximum number of transactions to process before committing progress to the database.
    pub commit_threshold: u64,
}

impl Default for SenderRecoveryConfig {
    fn default() -> Self {
        Self { commit_threshold: 5_000_000 }
    }
}

/// Execution stage configuration.
#[derive(Debug, Clone, Copy, Deserialize, PartialEq, Serialize)]
#[serde(default)]
pub struct ExecutionConfig {
    /// The maximum number of blocks to process before the execution stage commits.
    pub max_blocks: Option<u64>,
    /// The maximum amount of state changes to keep in memory before the execution stage commits.
    pub max_changes: Option<u64>,
}

impl Default for ExecutionConfig {
    fn default() -> Self {
        Self { max_blocks: Some(500_000), max_changes: Some(5_000_000) }
    }
}

/// Hashing stage configuration.
#[derive(Debug, Clone, Copy, Deserialize, PartialEq, Serialize)]
#[serde(default)]
pub struct HashingConfig {
    /// The threshold (in number of blocks) for switching between
    /// incremental hashing and full hashing.
    pub clean_threshold: u64,
    /// The maximum number of entities to process before committing progress to the database.
    pub commit_threshold: u64,
}

impl Default for HashingConfig {
    fn default() -> Self {
        Self { clean_threshold: 500_000, commit_threshold: 100_000 }
    }
}

/// Merkle stage configuration.
#[derive(Debug, Clone, Copy, Deserialize, PartialEq, Serialize)]
#[serde(default)]
pub struct MerkleConfig {
    /// The threshold (in number of blocks) for switching from incremental trie building of changes
    /// to whole rebuild.
    pub clean_threshold: u64,
}

impl Default for MerkleConfig {
    fn default() -> Self {
        Self { clean_threshold: 50_000 }
    }
}

/// Transaction Lookup stage configuration.
#[derive(Debug, Clone, Copy, Deserialize, PartialEq, Serialize)]
#[serde(default)]
pub struct TransactionLookupConfig {
    /// The maximum number of transactions to process before committing progress to the database.
    pub commit_threshold: u64,
}

impl Default for TransactionLookupConfig {
    fn default() -> Self {
        Self { commit_threshold: 5_000_000 }
    }
}

/// History History stage configuration.
#[derive(Debug, Clone, Copy, Deserialize, PartialEq, Serialize)]
#[serde(default)]
pub struct IndexHistoryConfig {
    /// The maximum number of blocks to process before committing progress to the database.
    pub commit_threshold: u64,
}

impl Default for IndexHistoryConfig {
    fn default() -> Self {
        Self { commit_threshold: 100_000 }
    }
}

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

    const EXTENSION: &str = "toml";

    fn with_tempdir(filename: &str, proc: fn(&std::path::Path)) {
        let temp_dir = tempfile::tempdir().unwrap();
        let config_path = temp_dir.path().join(filename).with_extension(EXTENSION);

        proc(&config_path);

        temp_dir.close().unwrap()
    }

    #[test]
    fn test_store_config() {
        with_tempdir("config-store-test", |config_path| {
            let config = Config::default();
            confy::store_path(config_path, config).unwrap();
        })
    }

    #[test]
    fn test_load_config() {
        with_tempdir("config-load-test", |config_path| {
            let config = Config::default();
            confy::store_path(config_path, &config).unwrap();

            let loaded_config: Config = confy::load_path(config_path).unwrap();
            assert_eq!(config, loaded_config);
        })
    }
}