#!/usr/bin/env python3
# Copyright (c) 2014-2020 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Test mempool re-org scenarios.

Test re-org scenarios with a mempool that contains transactions
that spend (directly or indirectly) coinbase transactions.
"""

from test_framework.blocktools import (
    COINBASE_MATURITY,
    create_raw_transaction,
)
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import assert_equal, assert_raises_rpc_error


class MempoolCoinbaseTest(BitcoinTestFramework):
    def set_test_params(self):
        self.num_nodes = 2
        self.extra_args = [
            [
                '-whitelist=noban@127.0.0.1',  # immediate tx relay
            ],
            []
        ]

    def skip_test_if_missing_module(self):
        self.skip_if_no_wallet()

    def run_test(self):
        # Start with a 200 block chain
        assert_equal(self.nodes[0].getblockcount(), 200)

        # Mine four blocks. After this, nodes[0] blocks
        # 101, 102, and 103 are spend-able.
        new_blocks = self.nodes[1].generate(4)
        self.sync_all()

        node0_address = self.nodes[0].getnewaddress()
        node1_address = self.nodes[1].getnewaddress()

        # Three scenarios for re-orging coinbase spends in the memory pool:
        # 1. Direct coinbase spend  :  spend_101
        # 2. Indirect (coinbase spend in chain, child in mempool) : spend_102 and spend_102_1
        # 3. Indirect (coinbase and child both in chain) : spend_103 and spend_103_1
        # Use invalidatblock to make all of the above coinbase spends invalid (immature coinbase),
        # and make sure the mempool code behaves correctly.
        b = [self.nodes[0].getblockhash(n) for n in range(COINBASE_MATURITY + 1, COINBASE_MATURITY + 5)]
        coinbase_txids = [self.nodes[0].getblock(h)['tx'][0] for h in b]
        spend_101_raw = create_raw_transaction(self.nodes[0], coinbase_txids[1], node1_address, amount=499.99)
        spend_102_raw = create_raw_transaction(self.nodes[0], coinbase_txids[2], node0_address, amount=499.99)
        spend_103_raw = create_raw_transaction(self.nodes[0], coinbase_txids[3], node0_address, amount=499.99)

        # Create a transaction which is time-locked to two blocks in the future
        timelock_tx = self.nodes[0].createrawtransaction(
            inputs=[{
                "txid": coinbase_txids[0],
                "vout": 0,
            }],
            outputs={node0_address: 499.99},
            locktime=self.nodes[0].getblockcount() + 2,
        )
        timelock_tx = self.nodes[0].signrawtransactionwithwallet(timelock_tx)["hex"]
        # This will raise an exception because the timelock transaction is too immature to spend
        assert_raises_rpc_error(-26, "non-final", self.nodes[0].sendrawtransaction, timelock_tx)

        # Broadcast and mine spend_102 and 103:
        spend_102_id = self.nodes[0].sendrawtransaction(spend_102_raw)
        spend_103_id = self.nodes[0].sendrawtransaction(spend_103_raw)
        self.nodes[0].generate(1)
        # Time-locked transaction is still too immature to spend
        assert_raises_rpc_error(-26, 'non-final', self.nodes[0].sendrawtransaction, timelock_tx)

        # Create 102_1 and 103_1:
        spend_102_1_raw = create_raw_transaction(self.nodes[0], spend_102_id, node1_address, amount=499.98)
        spend_103_1_raw = create_raw_transaction(self.nodes[0], spend_103_id, node1_address, amount=499.98)

        # Broadcast and mine 103_1:
        spend_103_1_id = self.nodes[0].sendrawtransaction(spend_103_1_raw)
        last_block = self.nodes[0].generate(1)
        # Sync blocks, so that peer 1 gets the block before timelock_tx
        # Otherwise, peer 1 would put the timelock_tx in m_recent_rejects
        self.sync_all()

        # Time-locked transaction can now be spent
        timelock_tx_id = self.nodes[0].sendrawtransaction(timelock_tx)

        # ... now put spend_101 and spend_102_1 in memory pools:
        spend_101_id = self.nodes[0].sendrawtransaction(spend_101_raw)
        spend_102_1_id = self.nodes[0].sendrawtransaction(spend_102_1_raw)

        assert_equal(set(self.nodes[0].getrawmempool()), {spend_101_id, spend_102_1_id, timelock_tx_id})
        self.sync_all()

        for node in self.nodes:
            node.invalidateblock(last_block[0])
        # Time-locked transaction is now too immature and has been removed from the mempool
        # spend_103_1 has been re-orged out of the chain and is back in the mempool
        assert_equal(set(self.nodes[0].getrawmempool()), {spend_101_id, spend_102_1_id, spend_103_1_id})

        # Use invalidateblock to re-org back and make all those coinbase spends
        # immature/invalid:
        for node in self.nodes:
            node.invalidateblock(new_blocks[0])

        # mempool should be empty.
        assert_equal(set(self.nodes[0].getrawmempool()), set())
        self.sync_all()


if __name__ == '__main__':
    MempoolCoinbaseTest().main()