// Copyright (C) 2024 Riften Labs AS
//
// This software is licensed under the GNU Affero General Public License (AGPL), version 3.0 or later.
// A copy of the license can be found in the LICENSE file or at https://www.gnu.org/licenses/agpl-3.0.html

use std::collections::{HashSet, VecDeque};

use bitcoincash::{Transaction, Txid};
use rayon::prelude::*;

// TTOR sort a list of transactions
pub fn ttor_sorted(txs: Vec<Transaction>) -> Vec<Transaction> {
    let txs = {
        let mut queue: VecDeque<Transaction> = txs.into_iter().collect();

        let mut queue_txids: HashSet<Txid> = queue.par_iter().map(|tx| tx.txid()).collect();

        let mut txs: Vec<Transaction> = Vec::with_capacity(queue.len());

        while let Some(tx) = queue.pop_front() {
            let mut has_parent = false;

            for i in &tx.input {
                if queue_txids.contains(&i.previous_output.txid) {
                    // depends on parent
                    has_parent = true;
                    break;
                };
            }

            if has_parent {
                queue.push_back(tx);
            } else {
                queue_txids.remove(&tx.txid());
                txs.push(tx)
            }
        }
        txs
    };
    txs
}