To-Local Output (in Alice's commitment transaction)

# To-Local Output (in Alice's commitment transaction)
# Alice can spend to herself after csv_delay blocks
# OR Bob can spend immediately if he has the revocation key
# (The revocation key punishes Alice for broadcasting an old state)

to_local_script (witnessScript):
  OP_IF
    # Revocation path: Bob has Alice's revocation secret
    <RevocationPubKey> OP_CHECKSIG
  OP_ELSE
    # Normal path: Alice after CSV delay
    <csv_delay> OP_CHECKSEQUENCEVERIFY OP_DROP
    <AliceDelayedPubKey> OP_CHECKSIG
  OP_ENDIF

# If Alice broadcasts her commitment transaction:
# - Bob has csv_delay blocks to broadcast a penalty transaction
#   using RevocationPubKey (if Alice is cheating with an old state)
# - If Bob doesn't act within csv_delay, Alice sweeps her funds normally

# HTLC-Timeout transaction (second-level, spends an offered HTLC output):
# Moves funds to a to_local-style output with csv_delay

# HTLC-Success transaction (second-level, spends a received HTLC output):
# Also moves funds to a to_local-style output with csv_delay

# Why? Because even after an HTLC is resolved, we still need the revocation
# window in case Alice cheated.

# Second-level output script:
  OP_IF
    <RevocationPubKey> OP_CHECKSIG
  OP_ELSE
    <csv_delay> OP_CHECKSEQUENCEVERIFY OP_DROP
    <LocalDelayedPubKey> OP_CHECKSIG
  OP_ENDIF

Timeline for cheating attempt and response:

Block N:   Alice broadcasts OLD commitment transaction (trying to cheat)
           Alice's to-local output has CSV delay of 144 blocks.

Blocks N to N+144:
           Bob's watchtower detects the old commitment transaction in a block.
           Bob (or his watchtower) constructs a "justice transaction":
           - Input 1: to-local output (using RevocationPubKey — Bob has this)
           - Input 2: any HTLCs (also using revocation)
           - Output: all funds → Bob's address (Alice loses everything)

Block N+144:
           If Bob hasn't acted, Alice can now sweep her to-local output.
           But Bob's justice transaction can no longer claim it.

# Anchor output script:
  <local_funding_pubkey> OP_CHECKSIG
  OP_IFDUP
  OP_NOTIF
    OP_2 OP_CSV
  OP_ENDIF

# The CSV(2) or CSV(1) at the end allows ANYONE to sweep the anchor
# after a short delay if the owner doesn't claim it.
# This prevents anchor UTXO spam accumulation.

# Simplified channel factory setup
class ChannelFactory:
    def __init__(self, participants, allocation_csv_delay, htlc_csv_delay):
        self.participants = participants
        self.allocation_csv_delay = allocation_csv_delay  # e.g., 288 blocks
        self.htlc_csv_delay = htlc_csv_delay              # e.g., 144 blocks

    def create_factory_script(self):
        # Factory output requires ALL participants to agree
        n = len(self.participants)
        keys = " ".join(p.pubkey for p in self.participants)
        return f"{n} {keys} {n} OP_CHECKMULTISIG"

    def min_cltv_for_htlc(self, hops_away):
        """
        HTLC CLTV expiry must account for all CSV delays along the path.
        Each hop needs at least htlc_csv_delay blocks for safety.
        """
        return hops_away * self.htlc_csv_delay + self.allocation_csv_delay