#!/usr/bin/env python3
# Copyright (c) 2015-2016 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Utilities for manipulating blocks and transactions."""

from .messages import (
    CBlock,
    CCbTx,
    COIN,
    COutPoint,
    CTransaction,
    CTxIn,
    CTxOut,
    ser_string,
)
from .script import CScript, OP_TRUE, OP_CHECKSIG

def create_block(hashprev, coinbase, ntime=None):
    """Create a block (with regtest difficulty)."""
    block = CBlock()
    if ntime is None:
        import time
        block.nTime = int(time.time() + 600)
    else:
        block.nTime = ntime
    block.hashPrevBlock = hashprev
    block.nBits = 0x207fffff  # difficulty retargeting is disabled in REGTEST chainparams
    block.vtx.append(coinbase)
    block.hashMerkleRoot = block.calc_merkle_root()
    block.calc_sha256()
    return block

def serialize_script_num(value):
    r = bytearray(0)
    if value == 0:
        return r
    neg = value < 0
    absvalue = -value if neg else value
    while (absvalue):
        r.append(int(absvalue & 0xff))
        absvalue >>= 8
    if r[-1] & 0x80:
        r.append(0x80 if neg else 0)
    elif neg:
        r[-1] |= 0x80
    return r

def create_coinbase(height, pubkey=None, dip4_activated=False):
    """Create a coinbase transaction, assuming no miner fees.

    If pubkey is passed in, the coinbase output will be a P2PK output;
    otherwise an anyone-can-spend output."""
    coinbase = CTransaction()
    coinbase.vin.append(CTxIn(COutPoint(0, 0xffffffff),
                        ser_string(serialize_script_num(height)), 0xffffffff))
    coinbaseoutput = CTxOut()
    coinbaseoutput.nValue = 500 * COIN
    halvings = int(height / 150)  # regtest
    coinbaseoutput.nValue >>= halvings
    if (pubkey is not None):
        coinbaseoutput.scriptPubKey = CScript([pubkey, OP_CHECKSIG])
    else:
        coinbaseoutput.scriptPubKey = CScript([OP_TRUE])
    coinbase.vout = [coinbaseoutput]
    if dip4_activated:
        coinbase.nVersion = 3
        coinbase.nType = 5
        cbtx_payload = CCbTx(2, height, 0, 0)
        coinbase.vExtraPayload = cbtx_payload.serialize()
    coinbase.calc_sha256()
    return coinbase

def create_transaction(prevtx, n, sig, value, script_pub_key=CScript()):
    """Create a transaction.

    If the script_pub_key is not specified, make it anyone-can-spend."""
    tx = CTransaction()
    assert(n < len(prevtx.vout))
    tx.vin.append(CTxIn(COutPoint(prevtx.sha256, n), sig, 0xffffffff))
    tx.vout.append(CTxOut(value, script_pub_key))
    tx.calc_sha256()
    return tx

def get_legacy_sigopcount_block(block, accurate=True):
    count = 0
    for tx in block.vtx:
        count += get_legacy_sigopcount_tx(tx, accurate)
    return count

def get_legacy_sigopcount_tx(tx, accurate=True):
    count = 0
    for i in tx.vout:
        count += i.scriptPubKey.GetSigOpCount(accurate)
    for j in tx.vin:
        # scriptSig might be of type bytes, so convert to CScript for the moment
        count += CScript(j.scriptSig).GetSigOpCount(accurate)
    return count

# Identical to GetMasternodePayment in C++ code
def get_masternode_payment(nHeight, blockValue, nReallocActivationHeight):
    ret = int(blockValue / 5)

    nMNPIBlock = 350
    nMNPIPeriod = 10

    if nHeight > nMNPIBlock:
        ret += int(blockValue / 20)
    if nHeight > nMNPIBlock+(nMNPIPeriod* 1):
        ret += int(blockValue / 20)
    if nHeight > nMNPIBlock+(nMNPIPeriod* 2):
        ret += int(blockValue / 20)
    if nHeight > nMNPIBlock+(nMNPIPeriod* 3):
        ret += int(blockValue / 40)
    if nHeight > nMNPIBlock+(nMNPIPeriod* 4):
        ret += int(blockValue / 40)
    if nHeight > nMNPIBlock+(nMNPIPeriod* 5):
        ret += int(blockValue / 40)
    if nHeight > nMNPIBlock+(nMNPIPeriod* 6):
        ret += int(blockValue / 40)
    if nHeight > nMNPIBlock+(nMNPIPeriod* 7):
        ret += int(blockValue / 40)
    if nHeight > nMNPIBlock+(nMNPIPeriod* 9):
        ret += int(blockValue / 40)

    if nHeight < nReallocActivationHeight:
        # Block Reward Realocation is not activated yet, nothing to do
        return ret

    nSuperblockCycle = 10
    # Actual realocation starts in the cycle next to one activation happens in
    nReallocStart = nReallocActivationHeight - nReallocActivationHeight % nSuperblockCycle + nSuperblockCycle

    if nHeight < nReallocStart:
        # Activated but we have to wait for the next cycle to start realocation, nothing to do
        return ret

    # Periods used to reallocate the masternode reward from 50% to 60%
    vecPeriods = [
        513, # Period 1:  51.3%
        526, # Period 2:  52.6%
        533, # Period 3:  53.3%
        540, # Period 4:  54%
        546, # Period 5:  54.6%
        552, # Period 6:  55.2%
        557, # Period 7:  55.7%
        562, # Period 8:  56.2%
        567, # Period 9:  56.7%
        572, # Period 10: 57.2%
        577, # Period 11: 57.7%
        582, # Period 12: 58.2%
        585, # Period 13: 58.5%
        588, # Period 14: 58.8%
        591, # Period 15: 59.1%
        594, # Period 16: 59.4%
        597, # Period 17: 59.7%
        599, # Period 18: 59.9%
        600  # Period 19: 60%
    ]

    nReallocCycle = nSuperblockCycle * 3
    nCurrentPeriod = min(int((nHeight - nReallocStart) / nReallocCycle), len(vecPeriods) - 1)

    return int(blockValue * vecPeriods[nCurrentPeriod] / 1000)