use std::sync::Arc;
use clap::Parser;

/// EVM Tracing CLI flags
#[derive(PartialEq, Clone, Debug)]
pub enum EthApi {
    /// Enable EVM debug RPC methods.
    Debug,
    /// Enable EVM trace RPC methods.
    Trace,
    /// Enable pending transactions RPC methods.
    TxPool,

}

impl std::str::FromStr for EthApi {
    type Err = String;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "debug" => Ok(EthApi::Debug),
            "trace" => Ok(EthApi::Trace),
            "txpool" => Ok(EthApi::TxPool),
            _ => Err(format!("Invalid EthApi: {}", s))
        }
    }
}

/// Available frontier backends
#[derive(PartialEq, Clone, Debug, Copy, clap::ValueEnum, Default)]
pub enum FrontierBackendType {
    /// RocksDB or ParityDB as inherited from the global settings
    #[default]
    KeyValue,
    /// Sql database with custom log indexing
    Sql
}

/// EVM Tracing CLI config
#[derive(Clone)]
pub struct EvmTracingConfig {
    /// Enabled EVM tracing flags.
    pub ethapi: Vec<EthApi>,
    /// Number of concurrent tracing tasks.
    pub ethapi_max_permits: u32,
    /// The Maximum number of trace entries a single request of `trace_filter` is allowed to return.
    /// A request asking for more or an unbounded one going over this limit will both return an
    /// error.
    pub ethapi_trace_max_count: u32,
    /// Duration (in seconds) after which the cache of `trace_filter` for a given block will be
    /// discarded.
    pub ethapi_trace_cache_duration: u64,
    /// Size in bytes of the LRU cache for block data.
    pub eth_log_block_cache: usize,
    /// Size in bytes of the LRU cache for transaction statuses data.
    pub eth_statuses_cache: usize,
    /// Maximum number of logs in a query.
    pub max_past_logs: u32,
    /// Size in bytes of data a raw tracing request is allowed to use.
    /// Bound the size of memory, stack and storage data.
    pub tracing_raw_max_memory_usage: usize,

    pub fee_history_limit: u64,
    pub frontier_backend_type: FrontierBackendType,
    pub frontier_sql_backend_pool_size: u32,
    pub frontier_sql_backend_num_ops_timeout: u32,
    pub frontier_sql_backend_thread_count: u32,
    pub frontier_sql_backend_cache_size: u64,
}

impl EthApiOptions {
    pub fn build_evm_tracing_config(&self) -> EvmTracingConfig {
        EvmTracingConfig {
            ethapi: self.ethapi.clone(),
            ethapi_max_permits: self.ethapi_max_permits,
            ethapi_trace_max_count: self.ethapi_trace_max_count,
            ethapi_trace_cache_duration: self.ethapi_trace_cache_duration,
            eth_log_block_cache: self.eth_log_block_cache,
            eth_statuses_cache: self.eth_statuses_cache,
            max_past_logs: self.max_past_logs,
            fee_history_limit: self.fee_history_limit,
            tracing_raw_max_memory_usage: self.tracing_raw_max_memory_usage,
            frontier_backend_type: self.frontier_backend_type,
            frontier_sql_backend_pool_size: self.frontier_sql_backend_pool_size,
            frontier_sql_backend_num_ops_timeout: self.frontier_sql_backend_num_ops_timeout,
            frontier_sql_backend_thread_count: self.frontier_sql_backend_thread_count,
            frontier_sql_backend_cache_size: self.frontier_sql_backend_cache_size,
        }
    }
}


#[derive(Debug, Parser)]
pub struct EthApiOptions {
    /// Enable EVM tracing module on a non-authority node.
    #[clap(
    long,
    conflicts_with = "validator",
    value_delimiter = ','
    )]
    pub ethapi: Vec<EthApi>,

    /// Number of concurrent tracing tasks. Meant to be shared by both "debug" and "trace" modules.
    #[clap(long, default_value = "10")]
    pub ethapi_max_permits: u32,

    /// The Maximum number of trace entries a single request of `trace_filter` is allowed to return.
    /// A request asking for more or an unbounded one going over this limit will both return an
    /// error.
    #[clap(long, default_value = "500")]
    pub ethapi_trace_max_count: u32,

    /// Duration (in seconds) after which the cache of `trace_filter` for a given block will be
    /// discarded.
    #[clap(long, default_value = "300")]
    pub ethapi_trace_cache_duration: u64,

    /// Sets the frontierBackend type, either KeyValue of SQL
    #[clap(long, value_enum, ignore_case = true, default_value_t = FrontierBackendType::default())]
    pub frontier_backend_type: FrontierBackendType,

    /// Size in bytes of the LRU cache for block data.
    #[clap(long, default_value = "300000000")]
    pub eth_log_block_cache: usize,

    /// Size in bytes of the LRU cache for transaction statuses data.
    #[clap(long, default_value = "300000000")]
    pub eth_statuses_cache: usize,

    /// Size in bytes of data a raw tracing request is allowed to use.
    /// Bound the size of memory, stack and storage data.
    #[clap(long, default_value = "20000000")]
    pub tracing_raw_max_memory_usage: usize,

    /// Maximum number of logs in a query.
    #[clap(long, default_value = "10000")]
    pub max_past_logs: u32,

    /// Maximum fee history cache size.
    #[arg(long, default_value = "2048")]
    pub fee_history_limit: u64,

    // Sets the SQL backend's pool size.
    #[arg(long, default_value = "100")]
    pub frontier_sql_backend_pool_size: u32,

    /// Sets the SQL backend's query timeout in number of VM ops.
    #[arg(long, default_value = "10000000")]
    pub frontier_sql_backend_num_ops_timeout: u32,

    /// Sets the SQL backend's auxiliary thread limit.
    #[arg(long, default_value = "4")]
    pub frontier_sql_backend_thread_count: u32,

    /// Sets the SQL backend's query timeout in number of VM ops.
    /// Default value is 200MB.
    #[arg(long, default_value = "209715200")]
    pub frontier_sql_backend_cache_size: u64,

}

pub(crate) fn db_config_dir(config: &sc_service::Configuration) -> std::path::PathBuf {
    config.base_path.config_dir(config.chain_spec.id())
}

/// Create a frontier backend
pub(crate) fn frontier_backend<B, C, BE>(
    config: &sc_service::Configuration,
    client: Arc<C>,
    eth_api_options: EvmTracingConfig,
) -> Result<fc_db::Backend<B>, String>
    where
        B: sp_runtime::traits::Block<Hash=sp_core::H256> + 'static,
        BE: sc_client_api::Backend<B> + 'static,
        C: sc_client_api::StorageProvider<B, BE> + Sync + Send + 'static
            + sp_api::ProvideRuntimeApi<B>
            + sc_client_api::HeaderBackend<B>,
        C::Api: fp_rpc::EthereumRuntimeRPCApi<B>,
{
    let db_config_dir = db_config_dir(config);
    let overrides_handle = fc_storage::overrides_handle(client.clone());
    match eth_api_options.frontier_backend_type {
        FrontierBackendType::KeyValue => {
            let db = fc_db::kv::Backend::open(
                client, &config.database, &db_config_dir)?;
            Ok(fc_db::Backend::<B>::KeyValue(db))
        },
        FrontierBackendType::Sql => {
            let db_path = db_config_dir.join("sql");
            std::fs::create_dir_all(&db_path).expect("failed creating sql db directory");
            let backend = futures::executor::block_on(fc_db::sql::Backend::new(
                fc_db::sql::BackendConfig::Sqlite(fc_db::sql::SqliteBackendConfig {
                    path: std::path::Path::new("sqlite:///")
                        .join(db_path)
                        .join("frontier.db3")
                        .to_str()
                        .unwrap(),
                    create_if_missing: true,
                    thread_count: eth_api_options.frontier_sql_backend_thread_count,
                    cache_size: eth_api_options.frontier_sql_backend_cache_size,
                }),
                eth_api_options.frontier_sql_backend_pool_size,
                std::num::NonZeroU32::new(eth_api_options.frontier_sql_backend_num_ops_timeout),
                overrides_handle,
            ))
                .unwrap_or_else(|err| panic!("failed creating sql backend: {:?}", err));
            Ok(fc_db::Backend::<B>::Sql(backend))
        }
    }
}