use crate::{
    client::Client,
    epm,
    error::Error,
    helpers::{kill_main_task_if_critical_err, signer_from_seed_or_path, TimedFuture},
    opt::Solver,
    prelude::*,
    prometheus, static_types,
};
use clap::Parser;
use codec::{Decode, Encode};
use frame_election_provider_support::NposSolution;
use futures::future::TryFutureExt;
use jsonrpsee::core::Error as JsonRpseeError;
use pallet_election_provider_multi_phase::{RawSolution, SolutionOf};
use sp_runtime::Perbill;
use std::{str::FromStr, sync::Arc};
use subxt::{
    backend::{legacy::rpc_methods::DryRunResult, rpc::RpcSubscription},
    config::{DefaultExtrinsicParamsBuilder, Header as _},
    error::RpcError,
    tx::{TxInBlock, TxProgress},
    Error as SubxtError,
};
use tokio::sync::Mutex;

#[derive(Debug, Clone, Parser)]
#[cfg_attr(test, derive(PartialEq))]
pub struct MonitorConfig {
    /// They type of event to listen to.
    ///
    /// Typically, finalized is safer and there is no chance of anything going wrong, but it can be
    /// slower. It is recommended to use finalized, if the duration of the signed phase is longer
    /// than the the finality delay.
    #[clap(long, value_enum, default_value_t = Listen::Finalized)]
    pub listen: Listen,

    /// The solver algorithm to use.
    #[clap(subcommand)]
    pub solver: Solver,

    /// Submission strategy to use.
    ///
    /// Possible options:
    ///
    /// `--submission-strategy if-leading`: only submit if leading.
    ///
    /// `--submission-strategy always`: always submit.
    ///
    /// `--submission-strategy "percent-better <percent>"`: submit if the submission is `n` percent better.
    ///
    /// `--submission-strategy "no-worse-than  <percent>"`: submit if submission is no more than `n` percent worse.
    #[clap(long, value_parser, default_value = "if-leading")]
    pub submission_strategy: SubmissionStrategy,

    /// The path to a file containing the seed of the account. If the file is not found, the seed is
    /// used as-is.
    ///
    /// Can also be provided via the `SEED` environment variable.
    ///
    /// WARNING: Don't use an account with a large stash for this. Based on how the bot is
    /// configured, it might re-try and lose funds through transaction fees/deposits.
    #[clap(long, short, env = "SEED")]
    pub seed_or_path: String,

    /// Delay in number seconds to wait until starting mining a solution.
    ///
    /// At every block when a solution is attempted
    /// a delay can be enforced to avoid submitting at
    /// "same time" and risk potential races with other miners.
    ///
    /// When this is enabled and there are competing solutions, your solution might not be submitted
    /// if the scores are equal.
    #[clap(long, default_value_t = 0)]
    pub delay: usize,

    /// Verify the submission by `dry-run` the extrinsic to check the validity.
    /// If the extrinsic is invalid then the submission is ignored and the next block will attempted again.
    ///
    /// This requires a RPC endpoint that exposes unsafe RPC methods, if the RPC endpoint doesn't expose unsafe RPC methods
    /// then the miner will be terminated.
    #[clap(long)]
    pub dry_run: bool,
}

/// The type of event to listen to.
///
///
/// Typically, finalized is safer and there is no chance of anything going wrong, but it can be
/// slower. It is recommended to use finalized, if the duration of the signed phase is longer
/// than the the finality delay.
#[cfg_attr(test, derive(PartialEq))]
#[derive(clap::ValueEnum, Debug, Copy, Clone)]
pub enum Listen {
    /// Latest finalized head of the canonical chain.
    Finalized,
    /// Latest head of the canonical chain.
    Head,
}

/// Submission strategy to use.
#[derive(Debug, Copy, Clone)]
#[cfg_attr(test, derive(PartialEq))]
pub enum SubmissionStrategy {
    /// Always submit.
    Always,
    // Submit if we are leading, or if the solution that's leading is more that the given `Perbill`
    // better than us. This helps detect obviously fake solutions and still combat them.
    /// Only submit if at the time, we are the best (or equal to it).
    IfLeading,
    /// Submit if we are no worse than `Perbill` worse than the best.
    ClaimNoWorseThan(Perbill),
    /// Submit if we are leading, or if the solution that's leading is more that the given `Perbill`
    /// better than us. This helps detect obviously fake solutions and still combat them.
    ClaimBetterThan(Perbill),
}

/// Custom `impl` to parse `SubmissionStrategy` from CLI.
///
/// Possible options:
/// * --submission-strategy if-leading: only submit if leading
/// * --submission-strategy always: always submit
/// * --submission-strategy "percent-better <percent>": submit if submission is `n` percent better.
///
impl FromStr for SubmissionStrategy {
    type Err = String;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let s = s.trim();

        let res = if s == "if-leading" {
            Self::IfLeading
        } else if s == "always" {
            Self::Always
        } else if let Some(percent) = s.strip_prefix("no-worse-than ") {
            let percent: u32 = percent.parse().map_err(|e| format!("{:?}", e))?;
            Self::ClaimNoWorseThan(Perbill::from_percent(percent))
        } else if let Some(percent) = s.strip_prefix("percent-better ") {
            let percent: u32 = percent.parse().map_err(|e| format!("{:?}", e))?;
            Self::ClaimBetterThan(Perbill::from_percent(percent))
        } else {
            return Err(s.into());
        };
        Ok(res)
    }
}

pub async fn monitor_cmd<T>(client: Client, config: MonitorConfig) -> Result<(), Error>
where
    T: MinerConfig<AccountId = AccountId, MaxVotesPerVoter = static_types::MaxVotesPerVoter>
        + Send
        + Sync
        + 'static,
    T::Solution: Send,
{
    let signer = signer_from_seed_or_path(&config.seed_or_path)?;

    let account_info = {
        let addr = runtime::storage()
            .system()
            .account(signer.public_key().to_account_id());
        client
            .chain_api()
            .storage()
            .at_latest()
            .await?
            .fetch(&addr)
            .await?
            .ok_or(Error::AccountDoesNotExists)?
    };

    log::info!(target: LOG_TARGET, "Loaded account {}, {:?}", signer.public_key().to_account_id(), account_info);

    if config.dry_run {
        // if we want to try-run, ensure the node supports it.
        dry_run_works(client.rpc()).await?;
    }

    let mut subscription = heads_subscription(client.rpc(), config.listen).await?;
    let (tx, mut rx) = tokio::sync::mpsc::unbounded_channel::<Error>();
    let submit_lock = Arc::new(Mutex::new(()));

    loop {
        let at = tokio::select! {
            maybe_rp = subscription.next() => {
                match maybe_rp {
                    Some(Ok(r)) => r,
                    Some(Err(e)) => {
                        log::error!(target: LOG_TARGET, "subscription failed to decode Header {:?}, this is bug please file an issue", e);
                        return Err(e.into());
                    }
                    // The subscription was dropped, should only happen if:
                    //	- the connection was closed.
                    //	- the subscription could not keep up with the server.
                    None => {
                        log::warn!(target: LOG_TARGET, "subscription to `{:?}` terminated. Retrying..", config.listen);
                        subscription = heads_subscription(client.rpc(), config.listen).await?;
                        continue
                    }
                }
            },
            maybe_err = rx.recv() => {
                match maybe_err {
                    Some(err) => return Err(err),
                    None => unreachable!("at least one sender kept in the main loop should always return Some; qed"),
                }
            }
        };

        // Spawn task and non-recoverable errors are sent back to the main task
        // such as if the connection has been closed.
        let tx2 = tx.clone();
        let client2 = client.clone();
        let signer2 = signer.clone();
        let config2 = config.clone();
        let submit_lock2 = submit_lock.clone();
        tokio::spawn(async move {
            if let Err(err) =
                mine_and_submit_solution::<T>(at, client2, signer2, config2, submit_lock2).await
            {
                kill_main_task_if_critical_err(&tx2, err)
            }
        });

        let account_info = client
            .chain_api()
            .storage()
            .at_latest()
            .await?
            .fetch(
                &runtime::storage()
                    .system()
                    .account(signer.public_key().to_account_id()),
            )
            .await?
            .ok_or(Error::AccountDoesNotExists)?;
        // this is lossy but fine for now.
        prometheus::set_balance(account_info.data.free as f64);
    }
}

/// Construct extrinsic at given block and watch it.
async fn mine_and_submit_solution<T>(
    at: Header,
    client: Client,
    signer: Signer,
    config: MonitorConfig,
    submit_lock: Arc<Mutex<()>>,
) -> Result<(), Error>
where
    T: MinerConfig<AccountId = AccountId, MaxVotesPerVoter = static_types::MaxVotesPerVoter>
        + Send
        + Sync
        + 'static,
    T::Solution: Send,
{
    let block_hash = at.hash();
    log::trace!(target: LOG_TARGET, "new event at #{:?} ({:?})", at.number, block_hash);

    // NOTE: as we try to send at each block then the nonce is used guard against
    // submitting twice. Because once a solution has been accepted on chain
    // the "next transaction" at a later block but with the same nonce will be rejected
    let nonce = client
        .rpc()
        .system_account_next_index(&signer.public_key().to_account_id())
        .await?;

    ensure_signed_phase(client.chain_api(), block_hash)
        .inspect_err(|e| {
            log::debug!(
                target: LOG_TARGET,
                "ensure_signed_phase failed: {:?}; skipping block: {}",
                e,
                at.number
            )
        })
        .await?;

    let round_fut = async {
        client
            .chain_api()
            .storage()
            .at(block_hash)
            .fetch_or_default(&runtime::storage().election_provider_multi_phase().round())
            .await
    };

    let round = round_fut
        .inspect_err(|e| log::error!(target: LOG_TARGET, "Mining solution failed: {:?}", e))
        .await?;

    ensure_no_previous_solution::<T::Solution>(
        client.chain_api(),
        block_hash,
        &signer.public_key().0.into(),
    )
    .inspect_err(|e| {
        log::debug!(
            target: LOG_TARGET,
            "ensure_no_previous_solution failed: {:?}; skipping block: {}",
            e,
            at.number
        )
    })
    .await?;

    tokio::time::sleep(std::time::Duration::from_secs(config.delay as u64)).await;
    let _lock = submit_lock.lock().await;

    let (solution, score) = match epm::fetch_snapshot_and_mine_solution::<T>(
        &client.chain_api(),
        Some(block_hash),
        config.solver,
        round,
        None,
    )
    .timed()
    .await
    {
        (Ok(mined_solution), elapsed) => {
            // check that the solution looks valid:
            mined_solution.feasibility_check()?;

            // and then get the values we need from it:
            let solution = mined_solution.solution();
            let score = mined_solution.score();
            let size = mined_solution.size();

            let elapsed_ms = elapsed.as_millis();
            let encoded_len = solution.encoded_size();
            let active_voters = solution.voter_count() as u32;
            let desired_targets = solution.unique_targets().len() as u32;

            let final_weight = tokio::task::spawn_blocking(move || {
                T::solution_weight(size.voters, size.targets, active_voters, desired_targets)
            })
            .await?;

            log::info!(
                target: LOG_TARGET,
                "Mined solution with {:?} size: {:?} round: {:?} at: {}, took: {} ms, len: {:?}, weight = {:?}",
                score,
                size,
                round,
                at.number(),
                elapsed_ms,
                encoded_len,
                final_weight,
            );

            prometheus::set_length(encoded_len);
            prometheus::set_weight(final_weight);
            prometheus::observe_mined_solution_duration(elapsed_ms as f64);
            prometheus::set_score(score);

            (solution, score)
        }
        (Err(e), _) => return Err(Error::Other(e.to_string())),
    };

    let best_head = get_latest_head(client.rpc(), config.listen).await?;

    ensure_signed_phase(client.chain_api(), best_head)
        .inspect_err(|e| {
            log::debug!(
                target: LOG_TARGET,
                "ensure_signed_phase failed: {:?}; skipping block: {}",
                e,
                at.number
            )
        })
        .await?;

    ensure_no_previous_solution::<T::Solution>(
        client.chain_api(),
        best_head,
        &signer.public_key().0.into(),
    )
    .inspect_err(|e| {
        log::debug!(
            target: LOG_TARGET,
            "ensure_no_previous_solution failed: {:?}; skipping block: {:?}",
            e,
            best_head,
        )
    })
    .await?;

    match ensure_solution_passes_strategy(
        client.chain_api(),
        best_head,
        score,
        config.submission_strategy,
    )
    .timed()
    .await
    {
        (Ok(_), now) => {
            log::trace!(
                target: LOG_TARGET,
                "Solution validity verification took: {} ms",
                now.as_millis()
            );
        }
        (Err(e), _) => {
            log::debug!(
                target: LOG_TARGET,
                "ensure_no_better_solution failed: {:?}; skipping block: {}",
                e,
                at.number
            );
            return Err(e);
        }
    };

    prometheus::on_submission_attempt();
    match submit_and_watch_solution::<T>(
        &client,
        signer,
        (solution, score, round),
        nonce,
        config.listen,
        config.dry_run,
        &at,
    )
    .timed()
    .await
    {
        (Ok(_), now) => {
            prometheus::on_submission_success();
            prometheus::observe_submit_and_watch_duration(now.as_millis() as f64);
        }
        (Err(e), _) => {
            log::warn!(
                target: LOG_TARGET,
                "submit_and_watch_solution failed: {e}; skipping block: {}",
                at.number
            );
        }
    };
    Ok(())
}

/// Ensure that now is the signed phase.
async fn ensure_signed_phase(api: &ChainClient, block_hash: Hash) -> Result<(), Error> {
    use pallet_election_provider_multi_phase::Phase;

    let addr = runtime::storage()
        .election_provider_multi_phase()
        .current_phase();
    let phase = api.storage().at(block_hash).fetch(&addr).await?;

    if let Some(Phase::Signed) = phase.map(|p| p.0) {
        Ok(())
    } else {
        Err(Error::IncorrectPhase)
    }
}

/// Ensure that our current `us` have not submitted anything previously.
async fn ensure_no_previous_solution<T>(
    api: &ChainClient,
    block_hash: Hash,
    us: &AccountId,
) -> Result<(), Error>
where
    T: NposSolution + scale_info::TypeInfo + Decode + 'static,
{
    let addr = runtime::storage()
        .election_provider_multi_phase()
        .signed_submission_indices();
    let indices = api.storage().at(block_hash).fetch_or_default(&addr).await?;

    for (_score, _, idx) in indices.0 {
        let submission = epm::signed_submission_at::<T>(idx, Some(block_hash), api).await?;

        if let Some(submission) = submission {
            if &submission.who == us {
                return Err(Error::AlreadySubmitted);
            }
        }
    }

    Ok(())
}

async fn ensure_solution_passes_strategy(
    api: &ChainClient,
    block_hash: Hash,
    score: sp_npos_elections::ElectionScore,
    strategy: SubmissionStrategy,
) -> Result<(), Error> {
    // don't care about current scores.
    if matches!(strategy, SubmissionStrategy::Always) {
        return Ok(());
    }

    let addr = runtime::storage()
        .election_provider_multi_phase()
        .signed_submission_indices();
    let indices = api.storage().at(block_hash).fetch_or_default(&addr).await?;

    log::debug!(target: LOG_TARGET, "submitted solutions: {:?}", indices.0);

    if indices.0.last().map_or(true, |(best_score, _, _)| {
        score_passes_strategy(score, best_score.0, strategy)
    }) {
        Ok(())
    } else {
        Err(Error::BetterScoreExist)
    }
}

async fn submit_and_watch_solution<T: MinerConfig + Send + Sync + 'static>(
    client: &Client,
    signer: Signer,
    (solution, score, round): (SolutionOf<T>, sp_npos_elections::ElectionScore, u32),
    nonce: u64,
    listen: Listen,
    dry_run: bool,
    at: &Header,
) -> Result<(), Error> {
    let tx = epm::signed_solution(RawSolution {
        solution,
        score,
        round,
    })?;

    // TODO: https://github.com/paritytech/polkadot-staking-miner/issues/730
    //
    // The extrinsic mortality length is static and doesn't know when the
    // signed phase ends.
    let signed_phase_len = client.chain_api().constants().at(&runtime::constants()
        .election_provider_multi_phase()
        .signed_phase())?;
    let xt_cfg = DefaultExtrinsicParamsBuilder::default()
        .mortal(at, signed_phase_len as u64)
        .build();

    let xt =
        client
            .chain_api()
            .tx()
            .create_signed_with_nonce(&tx, &signer, nonce as u64, xt_cfg)?;

    if dry_run {
        let dry_run_bytes = client.rpc().dry_run(xt.encoded(), None).await?;

        match dry_run_bytes.into_dry_run_result(&client.chain_api().metadata())? {
            DryRunResult::Success => (),
            DryRunResult::DispatchError(e) => {
                return Err(Error::TransactionRejected(e.to_string()))
            }
            DryRunResult::TransactionValidityError => {
                return Err(Error::TransactionRejected(
                    "TransactionValidityError".into(),
                ))
            }
        }
    }

    let tx_progress = xt.submit_and_watch().await.map_err(|e| {
        log::warn!(target: LOG_TARGET, "submit solution failed: {:?}", e);
        e
    })?;

    match listen {
        Listen::Head => {
            let in_block = wait_for_in_block(tx_progress).await?;
            let events = in_block.fetch_events().await.expect("events should exist");

            let solution_stored = events
                .find_first::<runtime::election_provider_multi_phase::events::SolutionStored>(
            );

            if let Ok(Some(_)) = solution_stored {
                log::info!("Included at {:?}", in_block.block_hash());
            } else {
                return Err(Error::Other(format!(
                    "No SolutionStored event found at {:?}",
                    in_block.block_hash()
                )));
            }
        }
        Listen::Finalized => {
            let finalized = tx_progress.wait_for_finalized_success().await?;

            let solution_stored = finalized
                .find_first::<runtime::election_provider_multi_phase::events::SolutionStored>(
            );

            if let Ok(Some(_)) = solution_stored {
                log::info!("Finalized at {:?}", finalized.block_hash());
            } else {
                return Err(Error::Other(format!(
                    "No SolutionStored event found at {:?}",
                    finalized.block_hash()
                )));
            }
        }
    };

    Ok(())
}

async fn heads_subscription(
    rpc: &RpcClient,
    listen: Listen,
) -> Result<RpcSubscription<Header>, Error> {
    match listen {
        Listen::Head => rpc.chain_subscribe_new_heads().await,
        Listen::Finalized => rpc.chain_subscribe_finalized_heads().await,
    }
    .map_err(Into::into)
}

async fn get_latest_head(rpc: &RpcClient, listen: Listen) -> Result<Hash, Error> {
    match listen {
        Listen::Head => match rpc.chain_get_block_hash(None).await {
            Ok(Some(hash)) => Ok(hash),
            Ok(None) => Err(Error::Other("Latest block not found".into())),
            Err(e) => Err(e.into()),
        },
        Listen::Finalized => rpc.chain_get_finalized_head().await.map_err(Into::into),
    }
}

/// Returns `true` if `our_score` better the onchain `best_score` according the given strategy.
pub(crate) fn score_passes_strategy(
    our_score: sp_npos_elections::ElectionScore,
    best_score: sp_npos_elections::ElectionScore,
    strategy: SubmissionStrategy,
) -> bool {
    match strategy {
        SubmissionStrategy::Always => true,
        SubmissionStrategy::IfLeading => {
            our_score.strict_threshold_better(best_score, Perbill::zero())
        }
        SubmissionStrategy::ClaimBetterThan(epsilon) => {
            our_score.strict_threshold_better(best_score, epsilon)
        }
        SubmissionStrategy::ClaimNoWorseThan(epsilon) => {
            !best_score.strict_threshold_better(our_score, epsilon)
        }
    }
}

async fn dry_run_works(rpc: &RpcClient) -> Result<(), Error> {
    if let Err(SubxtError::Rpc(RpcError::ClientError(e))) = rpc.dry_run(&[], None).await {
        let rpc_err = match e.downcast::<JsonRpseeError>() {
            Ok(e) => *e,
            Err(_) => {
                return Err(Error::Other(
                    "Failed to downcast RPC error; this is a bug please file an issue".to_string(),
                ))
            }
        };

        if let JsonRpseeError::Call(e) = rpc_err {
            if e.message() == "RPC call is unsafe to be called externally" {
                return Err(Error::Other(
                    "dry-run requires a RPC endpoint with `--rpc-methods unsafe`; \
                        either connect to another RPC endpoint or disable dry-run"
                        .to_string(),
                ));
            }
        }
    }
    Ok(())
}

/// Wait for the transaction to be in a block.
///
/// **Note:** transaction statuses like `Invalid`/`Usurped`/`Dropped` indicate with some
/// probability that the transaction will not make it into a block but there is no guarantee
/// that this is true. In those cases the stream is closed however, so you currently have no way to find
/// out if they finally made it into a block or not.
async fn wait_for_in_block<T, C>(mut tx: TxProgress<T, C>) -> Result<TxInBlock<T, C>, subxt::Error>
where
    T: subxt::Config,
    C: subxt::client::OnlineClientT<T>,
{
    use subxt::{error::TransactionError, tx::TxStatus};

    while let Some(status) = tx.next().await {
        match status? {
            // Finalized or otherwise in a block! Return.
            TxStatus::InBestBlock(s) | TxStatus::InFinalizedBlock(s) => return Ok(s),
            // Error scenarios; return the error.
            TxStatus::Error { message } => return Err(TransactionError::Error(message).into()),
            TxStatus::Invalid { message } => return Err(TransactionError::Invalid(message).into()),
            TxStatus::Dropped { message } => return Err(TransactionError::Dropped(message).into()),
            // Ignore anything else and wait for next status event:
            _ => continue,
        }
    }
    Err(RpcError::SubscriptionDropped.into())
}

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

    #[test]
    fn score_passes_strategy_works() {
        let s = |x| sp_npos_elections::ElectionScore {
            minimal_stake: x,
            ..Default::default()
        };
        let two = Perbill::from_percent(2);

        // anything passes Always
        assert!(score_passes_strategy(
            s(0),
            s(0),
            SubmissionStrategy::Always
        ));
        assert!(score_passes_strategy(
            s(5),
            s(0),
            SubmissionStrategy::Always
        ));
        assert!(score_passes_strategy(
            s(5),
            s(10),
            SubmissionStrategy::Always
        ));

        // if leading
        assert!(!score_passes_strategy(
            s(0),
            s(0),
            SubmissionStrategy::IfLeading
        ));
        assert!(score_passes_strategy(
            s(1),
            s(0),
            SubmissionStrategy::IfLeading
        ));
        assert!(score_passes_strategy(
            s(2),
            s(0),
            SubmissionStrategy::IfLeading
        ));
        assert!(!score_passes_strategy(
            s(5),
            s(10),
            SubmissionStrategy::IfLeading
        ));
        assert!(!score_passes_strategy(
            s(9),
            s(10),
            SubmissionStrategy::IfLeading
        ));
        assert!(!score_passes_strategy(
            s(10),
            s(10),
            SubmissionStrategy::IfLeading
        ));

        // if better by 2%
        assert!(!score_passes_strategy(
            s(50),
            s(100),
            SubmissionStrategy::ClaimBetterThan(two)
        ));
        assert!(!score_passes_strategy(
            s(100),
            s(100),
            SubmissionStrategy::ClaimBetterThan(two)
        ));
        assert!(!score_passes_strategy(
            s(101),
            s(100),
            SubmissionStrategy::ClaimBetterThan(two)
        ));
        assert!(!score_passes_strategy(
            s(102),
            s(100),
            SubmissionStrategy::ClaimBetterThan(two)
        ));
        assert!(score_passes_strategy(
            s(103),
            s(100),
            SubmissionStrategy::ClaimBetterThan(two)
        ));
        assert!(score_passes_strategy(
            s(150),
            s(100),
            SubmissionStrategy::ClaimBetterThan(two)
        ));

        // if no less than 2% worse
        assert!(!score_passes_strategy(
            s(50),
            s(100),
            SubmissionStrategy::ClaimNoWorseThan(two)
        ));
        assert!(!score_passes_strategy(
            s(97),
            s(100),
            SubmissionStrategy::ClaimNoWorseThan(two)
        ));
        assert!(score_passes_strategy(
            s(98),
            s(100),
            SubmissionStrategy::ClaimNoWorseThan(two)
        ));
        assert!(score_passes_strategy(
            s(99),
            s(100),
            SubmissionStrategy::ClaimNoWorseThan(two)
        ));
        assert!(score_passes_strategy(
            s(100),
            s(100),
            SubmissionStrategy::ClaimNoWorseThan(two)
        ));
        assert!(score_passes_strategy(
            s(101),
            s(100),
            SubmissionStrategy::ClaimNoWorseThan(two)
        ));
        assert!(score_passes_strategy(
            s(102),
            s(100),
            SubmissionStrategy::ClaimNoWorseThan(two)
        ));
        assert!(score_passes_strategy(
            s(103),
            s(100),
            SubmissionStrategy::ClaimNoWorseThan(two)
        ));
        assert!(score_passes_strategy(
            s(150),
            s(100),
            SubmissionStrategy::ClaimNoWorseThan(two)
        ));
    }

    #[test]
    fn submission_strategy_from_str_works() {
        assert_eq!(
            SubmissionStrategy::from_str("if-leading"),
            Ok(SubmissionStrategy::IfLeading)
        );
        assert_eq!(
            SubmissionStrategy::from_str("always"),
            Ok(SubmissionStrategy::Always)
        );
        assert_eq!(
            SubmissionStrategy::from_str("  percent-better 99   "),
            Ok(SubmissionStrategy::ClaimBetterThan(Accuracy::from_percent(
                99
            )))
        );
    }
}