use std::sync::Mutex;
#[cfg(feature = "multisig")]
use std::collections::HashMap;

use lazy_static::lazy_static;

use rand::rngs::OsRng;

#[cfg(feature = "multisig")]
use blake2::{digest::Update, Digest, Blake2b512};

use curve25519_dalek::constants::ED25519_BASEPOINT_TABLE;

#[cfg(feature = "multisig")]
use dalek_ff_group::Scalar;
#[cfg(feature = "multisig")]
use frost::tests::{THRESHOLD, key_gen, sign};

use monero::{
  network::Network,
  util::{key::PublicKey, address::Address}
};

use monero_serai::{random_scalar, wallet::SignableTransaction};

mod rpc;
use crate::rpc::{rpc, mine_block};

#[cfg(feature = "multisig")]
use monero_serai::frost::{Transcript, Ed25519};

lazy_static! {
  static ref SEQUENTIAL: Mutex<()> = Mutex::new(());
}

macro_rules! async_sequential {
  ($(async fn $name: ident() $body: block)*) => {
    $(
      #[tokio::test]
      async fn $name() {
        let guard = SEQUENTIAL.lock().unwrap();
        let local = tokio::task::LocalSet::new();
        local.run_until(async move {
          if let Err(err) = tokio::task::spawn_local(async move { $body }).await {
            drop(guard);
            Err(err).unwrap()
          }
        }).await;
      }
    )*
  };
}

async fn send_core(test: usize, multisig: bool) {
  let rpc = rpc().await;

  // Generate an address
  let spend = random_scalar(&mut OsRng);
  #[allow(unused_mut)]
  let mut view = random_scalar(&mut OsRng);
  #[allow(unused_mut)]
  let mut spend_pub = &spend * &ED25519_BASEPOINT_TABLE;

  #[cfg(feature = "multisig")]
  let keys = key_gen::<_, Ed25519>(&mut OsRng);

  if multisig {
    #[cfg(not(feature = "multisig"))]
    panic!("Running a multisig test without the multisig feature");
    #[cfg(feature = "multisig")]
    {
      view = Scalar::from_hash(Blake2b512::new().chain("Monero Serai Transaction Test")).0;
      spend_pub = keys[&1].group_key().0;
    }
  }

  let addr = Address::standard(
    Network::Mainnet,
    PublicKey { point: spend_pub.compress() },
    PublicKey { point: (&view * &ED25519_BASEPOINT_TABLE).compress() }
  );

  // TODO
  let fee_per_byte = 50000000;
  let fee = fee_per_byte * 2000;

  let start = rpc.get_height().await.unwrap();
  for _ in 0 .. 7 {
    mine_block(&rpc, &addr.to_string()).await.unwrap();
  }

  let mut tx = None;
  // Allow tests to test variable transactions
  for i in 0 .. [2, 1][test] {
    let mut outputs = vec![];
    let mut amount = 0;
    // Test spending both a miner output and a normal output
    if test == 0 {
      if i == 0 {
        tx = Some(rpc.get_block_transactions(start).await.unwrap().swap_remove(0));
      }

      // Grab the largest output available
      let output = {
        let mut outputs = tx.as_ref().unwrap().scan(view, spend_pub).0;
        outputs.sort_by(|x, y| x.commitment.amount.cmp(&y.commitment.amount).reverse());
        outputs.swap_remove(0)
      };
      // Test creating a zero change output and a non-zero change output
      amount = output.commitment.amount - u64::try_from(i).unwrap();
      outputs.push(output);

    // Test spending multiple inputs
    } else if test == 1 {
      if i != 0 {
        continue;
      }

      // We actually need 80 decoys for this transaction, so mine until then
      // 80 + 60 (miner TX maturity) + 10 (lock blocks)
      // It is possible for this to be lower, by noting maturity is sufficient regardless of lock
      // blocks, yet that's not currently implemented
      // TODO, if we care
      while rpc.get_height().await.unwrap() < 160 {
        mine_block(&rpc, &addr.to_string()).await.unwrap();
      }

      for i in (start + 1) .. (start + 9) {
        let tx = rpc.get_block_transactions(i).await.unwrap().swap_remove(0);
        let output = tx.scan(view, spend_pub).0.swap_remove(0);
        amount += output.commitment.amount;
        outputs.push(output);
      }
    }

    let mut signable = SignableTransaction::new(
      outputs, vec![(addr, amount - fee)], addr, fee_per_byte
    ).unwrap();

    if !multisig {
      tx = Some(signable.sign(&mut OsRng, &rpc, &spend).await.unwrap());
    } else {
      #[cfg(feature = "multisig")]
      {
        let mut machines = HashMap::new();
        for i in 1 ..= THRESHOLD {
          machines.insert(
            i,
            signable.clone().multisig(
              &mut OsRng,
              &rpc,
              (*keys[&i]).clone(),
              Transcript::new(b"Monero Serai Test Transaction"),
              rpc.get_height().await.unwrap() - 10,
              (1 ..= THRESHOLD).collect::<Vec<_>>()
            ).await.unwrap()
          );
        }

        tx = Some(sign(&mut OsRng, machines, &vec![]));
      }
    }

    rpc.publish_transaction(tx.as_ref().unwrap()).await.unwrap();
    mine_block(&rpc, &addr.to_string()).await.unwrap();
  }
}

async_sequential! {
  async fn send_single_input() {
    send_core(0, false).await;
  }

  async fn send_multiple_inputs() {
    send_core(1, false).await;
  }
}

#[cfg(feature = "multisig")]
async_sequential! {
  async fn multisig_send_single_input() {
    send_core(0, true).await;
  }

  async fn multisig_send_multiple_inputs() {
    send_core(1, true).await;
  }
}