use crate::{checks, LocalNetwork};
use clap::ArgMatches;
use futures::prelude::*;
use node_test_rig::{
    environment::EnvironmentBuilder, testing_client_config, ClientGenesis, ValidatorConfig,
};
use std::net::{IpAddr, Ipv4Addr};
use std::time::{Duration, SystemTime, UNIX_EPOCH};

pub fn run_no_eth1_sim(matches: &ArgMatches) -> Result<(), String> {
    let node_count = value_t!(matches, "nodes", usize).expect("missing nodes default");
    let validators_per_node = value_t!(matches, "validators_per_node", usize)
        .expect("missing validators_per_node default");
    let speed_up_factor =
        value_t!(matches, "speed_up_factor", u64).expect("missing speed_up_factor default");
    let mut end_after_checks = true;
    if matches.is_present("end_after_checks") {
        end_after_checks = false;
    }

    println!("Beacon Chain Simulator:");
    println!(" nodes:{}", node_count);
    println!(" validators_per_node:{}", validators_per_node);
    println!(" end_after_checks:{}", end_after_checks);

    let log_level = "debug";
    let log_format = None;

    let mut env = EnvironmentBuilder::mainnet()
        .async_logger(log_level, log_format)?
        .multi_threaded_tokio_runtime()?
        .build()?;

    let eth1_block_time = Duration::from_millis(15_000 / speed_up_factor);

    let spec = &mut env.eth2_config.spec;

    spec.milliseconds_per_slot /= speed_up_factor;
    spec.eth1_follow_distance = 16;
    spec.min_genesis_delay = eth1_block_time.as_secs() * spec.eth1_follow_distance * 2;
    spec.min_genesis_time = 0;
    spec.min_genesis_active_validator_count = 64;
    spec.seconds_per_eth1_block = 1;

    let genesis_time = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map_err(|_| "should get system time")?
        + Duration::from_secs(5);

    let slot_duration = Duration::from_millis(spec.milliseconds_per_slot);
    let total_validator_count = validators_per_node * node_count;

    let context = env.core_context();

    let mut beacon_config = testing_client_config();

    beacon_config.genesis = ClientGenesis::Interop {
        validator_count: total_validator_count,
        genesis_time: genesis_time.as_secs(),
    };
    beacon_config.dummy_eth1_backend = true;
    beacon_config.sync_eth1_chain = true;

    beacon_config.network.enr_address = Some(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)));

    let main_future = async {
        let network = LocalNetwork::new(context, beacon_config.clone()).await?;
        /*
         * One by one, add beacon nodes to the network.
         */

        for _ in 0..node_count - 1 {
            network.add_beacon_node(beacon_config.clone()).await?;
        }
        /*
         * One by one, add validator clients to the network. Each validator client is attached to
         * a single corresponding beacon node.
         */

        // Note: presently the validator client future will only resolve once genesis time
        // occurs. This is great for this scenario, but likely to change in the future.
        //
        // If the validator client future behaviour changes, we would need to add a new future
        // that delays until genesis. Otherwise, all of the checks that start in the next
        // future will start too early.

        for i in 0..node_count {
            let indices =
                (i * validators_per_node..(i + 1) * validators_per_node).collect::<Vec<_>>();
            network
                .add_validator_client(
                    ValidatorConfig {
                        auto_register: true,
                        ..ValidatorConfig::default()
                    },
                    i,
                    indices,
                )
                .await?;
        }
        /*
         * Start the processes that will run checks on the network as it runs.
         */
        // Check that the chain finalizes at the first given opportunity.
        checks::verify_first_finalization(network.clone(), slot_duration).await?;

        // The `final_future` either completes immediately or never completes, depending on the value
        // of `end_after_checks`.

        if !end_after_checks {
            future::pending::<()>().await;
        }
        /*
         * End the simulation by dropping the network. This will kill all running beacon nodes and
         * validator clients.
         */
        println!(
            "Simulation complete. Finished with {} beacon nodes and {} validator clients",
            network.beacon_node_count(),
            network.validator_client_count()
        );

        // Be explicit about dropping the network, as this kills all the nodes. This ensures
        // all the checks have adequate time to pass.
        drop(network);
        Ok::<(), String>(())
    };

    Ok(env.runtime().block_on(main_future).unwrap())
}