Contractless/src/orphans/undo_transactions/undo_burn.rs

use crate::blocks::burn::BurnTransaction;
use crate::common::network_paths_and_settings::block_extension_and_paths;
use crate::common::nft_assets::nft_asset_name;
use crate::decode;
use crate::records::balance_sheet::operations::balance_sheet_operation_with_db;
use crate::records::record_chain::nft_provenance::remove_nft_history_entry;
use crate::records::record_chain::token_provenance::remove_token_history_entry;
use crate::sled::Db;

pub async fn undo_burn_transaction(transaction: BurnTransaction, mining_receiver: &str, db: &Db) {
    // Reverse the burn fee and burned-asset balance movement before
    // restoring the live token or NFT state back into the active chain.
    let operand_subtraction = "subtraction";
    let operand_addition = "addition";
    let (
        _network_name,
        _padded_base_coin,
        type_str,
        _torrentpath,
        _wallet_path,
        _blockpath,
        _db_path,
        _balance_path,
        _log_path,
    ) = block_extension_and_paths();
    let burned_asset = nft_asset_name(
        &transaction.unsigned_burn.coin,
        transaction.unsigned_burn.nft_series,
    );

    // Remove the miner fee, refund the burner fee, and return the burned asset
    // to the burner balance.
    let _ = balance_sheet_operation_with_db(
        db,
        mining_receiver,
        transaction.unsigned_burn.txfee,
        &type_str,
        operand_subtraction,
    );
    let _ = balance_sheet_operation_with_db(
        db,
        &transaction.unsigned_burn.address,
        transaction.unsigned_burn.txfee,
        &type_str,
        operand_addition,
    );
    let _ = balance_sheet_operation_with_db(
        db,
        &transaction.unsigned_burn.address,
        transaction.unsigned_burn.value,
        &burned_asset,
        operand_addition,
    );

    let hash_binary = decode(&transaction.unsigned_burn.hash().await).unwrap();

    // Delete the txid lookup inserted when the burn was saved.
    let txid_tree = db.open_tree("txid").unwrap();
    txid_tree.remove(hash_binary.clone()).unwrap();

    // Restore NFT rows directly, or add the burned amount back into the
    // fungible token supply if this burn targeted a token asset.
    let nft_tree = db.open_tree("nfts").unwrap();
    let nft_origin_tree = db.open_tree("nft_origins").unwrap();
    if nft_origin_tree
        .contains_key(burned_asset.as_bytes())
        .unwrap_or(false)
    {
        // NFT burns remove the live NFT row; rollback restores the row and
        // removes the burn from NFT history.
        let _ = remove_nft_history_entry(db, &burned_asset, &hash_binary);
        let _ = nft_tree.insert(burned_asset.as_bytes(), b"1");
    } else {
        // Token burns reduce supply; rollback adds the burned amount back.
        let _ = remove_token_history_entry(db, &transaction.unsigned_burn.coin, &hash_binary);
        let token_tree = db.open_tree("tokens").unwrap();
        let current_supply = token_tree
            .get(transaction.unsigned_burn.coin.as_bytes())
            .unwrap()
            .map(|bytes| {
                let mut supply_bytes = [0u8; 8];
                supply_bytes.copy_from_slice(bytes.as_ref());
                u64::from_le_bytes(supply_bytes)
            })
            .unwrap_or(0);
        let restored_supply = current_supply.saturating_add(transaction.unsigned_burn.value);
        let _ = token_tree.insert(
            transaction.unsigned_burn.coin.as_bytes(),
            &restored_supply.to_le_bytes(),
        );
    }
}