use std::{env, process, time::Duration};

use anyhow::{Context as _, Result};
use runner_examples::{ChaosBuilderExt as _, ScenarioBuilderExt as _, read_env_any};
use testing_framework_core::scenario::{Deployer as _, Runner, ScenarioBuilder};
use testing_framework_runner_compose::{ComposeDeployer, ComposeRunnerError};
use tracing::{info, warn};

const DEFAULT_VALIDATORS: usize = 1;
const DEFAULT_EXECUTORS: usize = 1;
const DEFAULT_RUN_SECS: u64 = 60;
const MIXED_TXS_PER_BLOCK: u64 = 5;
const TOTAL_WALLETS: usize = 1000;
const TRANSACTION_WALLETS: usize = 500;

// Chaos Testing Constants
const CHAOS_MIN_DELAY_SECS: u64 = 120;
const CHAOS_MAX_DELAY_SECS: u64 = 180;
const CHAOS_COOLDOWN_SECS: u64 = 240;
const CHAOS_DELAY_HEADROOM_SECS: u64 = 1;

// DA Testing Constants
const DA_CHANNEL_RATE: u64 = 1;
const DA_BLOB_RATE: u64 = 1;

#[tokio::main]
async fn main() {
    // Compose containers mount KZG params at /kzgrs_test_params; ensure the
    // generated configs point there unless the caller overrides explicitly.
    if env::var("NOMOS_KZGRS_PARAMS_PATH").is_err() {
        // Safe: setting a process-wide environment variable before any threads
        // or async tasks are spawned.
        unsafe {
            env::set_var(
                "NOMOS_KZGRS_PARAMS_PATH",
                "/kzgrs_test_params/kzgrs_test_params",
            );
        }
    }

    tracing_subscriber::fmt::init();

    let validators = read_env_any(
        &["NOMOS_DEMO_VALIDATORS", "COMPOSE_DEMO_VALIDATORS"],
        DEFAULT_VALIDATORS,
    );
    let executors = read_env_any(
        &["NOMOS_DEMO_EXECUTORS", "COMPOSE_DEMO_EXECUTORS"],
        DEFAULT_EXECUTORS,
    );
    let run_secs = read_env_any(
        &["NOMOS_DEMO_RUN_SECS", "COMPOSE_DEMO_RUN_SECS"],
        DEFAULT_RUN_SECS,
    );
    info!(
        validators,
        executors, run_secs, "starting compose runner demo"
    );

    if let Err(err) = run_compose_case(validators, executors, Duration::from_secs(run_secs)).await {
        warn!("compose runner demo failed: {err}");
        process::exit(1);
    }
}

async fn run_compose_case(
    validators: usize,
    executors: usize,
    run_duration: Duration,
) -> Result<()> {
    info!(
        validators,
        executors,
        duration_secs = run_duration.as_secs(),
        "building scenario plan"
    );

    let (chaos_min_delay, chaos_max_delay, chaos_target_cooldown) = chaos_timings(run_duration);

    let mut plan = ScenarioBuilder::topology_with(|t| {
        t.network_star().validators(validators).executors(executors)
    })
    .enable_node_control()
    .chaos_with(|c| {
        c.restart()
            // Keep chaos restarts outside the test run window to avoid crash loops on restart.
            .min_delay(chaos_min_delay)
            .max_delay(chaos_max_delay)
            .target_cooldown(chaos_target_cooldown)
            .apply()
    })
    .wallets(TOTAL_WALLETS)
    .transactions_with(|txs| txs.rate(MIXED_TXS_PER_BLOCK).users(TRANSACTION_WALLETS))
    .da_with(|da| da.channel_rate(DA_CHANNEL_RATE).blob_rate(DA_BLOB_RATE))
    .with_run_duration(run_duration)
    .expect_consensus_liveness()
    .build();

    let deployer = ComposeDeployer::new();
    info!("deploying compose stack");

    let runner: Runner = match deployer.deploy(&plan).await {
        Ok(runner) => runner,
        Err(ComposeRunnerError::DockerUnavailable) => {
            warn!("Docker is unavailable; cannot run compose demo");
            return Ok(());
        }
        Err(err) => return Err(anyhow::Error::new(err)).context("deploying compose stack failed"),
    };

    if !runner.context().telemetry().is_configured() {
        warn!("metrics querying is disabled; set NOMOS_METRICS_QUERY_URL to enable PromQL queries");
    }

    info!("running scenario");
    runner
        .run(&mut plan)
        .await
        .context("running compose scenario failed")?;
    Ok(())
}

fn chaos_timings(run_duration: Duration) -> (Duration, Duration, Duration) {
    let headroom = Duration::from_secs(CHAOS_DELAY_HEADROOM_SECS);
    let chaos_min_delay = Duration::from_secs(CHAOS_MIN_DELAY_SECS).max(run_duration + headroom);
    let chaos_max_delay = Duration::from_secs(CHAOS_MAX_DELAY_SECS).max(chaos_min_delay);
    let chaos_target_cooldown = Duration::from_secs(CHAOS_COOLDOWN_SECS).max(chaos_min_delay);

    (chaos_min_delay, chaos_max_delay, chaos_target_cooldown)
}

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

    #[test]
    fn chaos_cooldown_is_never_less_than_min_delay() {
        let (min_delay, _max_delay, cooldown) = chaos_timings(Duration::from_secs(600));
        assert!(cooldown >= min_delay);
    }
}