import base64
import hashlib
import json
import struct
import sys

from solders.transaction import Transaction, VersionedTransaction


def load_idl(file_path):
    with open(file_path) as f:
        return json.load(f)


def load_transaction(file_path):
    with open(file_path) as f:
        data = json.load(f)
    return data


def decode_instruction(ix_data, ix_def):
    """Decode an instruction's args based on its IDL definition.

    Supports the primitive scalar types and the `OptionBool` defined type
    (added in the late-Feb 2026 cashback upgrade — `OptionBool` is a struct
    wrapping a single bool, so it serializes as 1 byte on the wire).

    Trailing args can be absent from the wire entirely: two real mainnet
    `create_v2` instructions carry `0001` and `00` respectively after `creator`,
    so `is_cashback_enabled` is there in one and omitted in the other. Anything
    the data runs out for is reported as None rather than raising.
    """
    args = {}
    offset = 8  # Skip 8-byte discriminator

    # Width each type needs before it can be read at all; strings carry their own
    # 4-byte length prefix.
    widths = {
        "u64": 8,
        "i64": 8,
        "u32": 4,
        "u16": 2,
        "u8": 1,
        "bool": 1,
        "pubkey": 32,
        "string": 4,
    }

    for arg in ix_def["args"]:
        t = arg["type"]
        needed = widths.get(t, 1) if isinstance(t, str) else 1
        if offset + needed > len(ix_data):
            # Truncated trailing arg: the sender omitted it.
            args[arg["name"]] = None
            continue

        if t == "u64":
            value = struct.unpack_from("<Q", ix_data, offset)[0]
            offset += 8
        elif t == "i64":
            value = struct.unpack_from("<q", ix_data, offset)[0]
            offset += 8
        elif t == "u32":
            value = struct.unpack_from("<I", ix_data, offset)[0]
            offset += 4
        elif t == "u16":
            value = struct.unpack_from("<H", ix_data, offset)[0]
            offset += 2
        elif t == "u8":
            value = ix_data[offset]
            offset += 1
        elif t == "bool":
            value = bool(ix_data[offset])
            offset += 1
        elif t == "pubkey":
            value = ix_data[offset : offset + 32].hex()
            offset += 32
        elif t == "string":
            length = struct.unpack_from("<I", ix_data, offset)[0]
            offset += 4
            value = ix_data[offset : offset + length].decode("utf-8")
            offset += length
        elif isinstance(t, dict) and "defined" in t:
            defined_name = t["defined"]["name"] if isinstance(t["defined"], dict) else t["defined"]
            if defined_name == "OptionBool":
                value = bool(ix_data[offset])
                offset += 1
            else:
                raise ValueError(f"Unsupported defined type: {defined_name}")
        else:
            raise ValueError(f"Unsupported type: {t}")

        args[arg["name"]] = value

    return args


def calculate_discriminator(instruction_name):
    sha = hashlib.sha256()
    sha.update(instruction_name.encode("utf-8"))
    discriminator_bytes = sha.digest()[:8]
    discriminator = struct.unpack("<Q", discriminator_bytes)[0]
    return discriminator


def decode_transaction(tx_data, idl):
    decoded_instructions = []

    # Decode the base64 transaction data
    tx_data_decoded = base64.b64decode(tx_data["transaction"][0])

    # Check if it's a versioned transaction
    if tx_data.get("version") == 0:
        # Use solders library for versioned transactions
        transaction = VersionedTransaction.from_bytes(tx_data_decoded)
        instructions = transaction.message.instructions
        account_keys = transaction.message.account_keys
        print("Versioned transaction detected")
    else:
        # Use legacy deserialization for older transactions
        transaction = Transaction.from_bytes(tx_data_decoded)
        instructions = transaction.message.instructions
        account_keys = transaction.message.account_keys
        print("Legacy transaction detected")

    print(f"Number of instructions: {len(instructions)}")

    for idx, ix in enumerate(instructions):
        program_id = str(account_keys[ix.program_id_index])
        print(f"\nInstruction {idx}:")
        print(f"Program ID: {program_id}")

        if (
            program_id == "6EF8rrecthR5Dkzon8Nwu78hRvfCKubJ14M5uBEwF6P"
        ):  # Pump Fun Program
            ix_data = bytes(ix.data)
            discriminator = struct.unpack("<Q", ix_data[:8])[0]

            print(f"Discriminator: {discriminator:016x}")

            for idl_ix in idl["instructions"]:
                idl_discriminator = calculate_discriminator(f"global:{idl_ix['name']}")

                if discriminator == idl_discriminator:
                    decoded_args = decode_instruction(ix_data, idl_ix)
                    accounts = [str(account_keys[acc_idx]) for acc_idx in ix.accounts]
                    decoded_instructions.append(
                        {
                            "name": idl_ix["name"],
                            "args": decoded_args,
                            "accounts": accounts,
                            "program": program_id,
                        }
                    )
                    break
            else:
                decoded_instructions.append(
                    {
                        "name": "Unknown",
                        "data": ix_data.hex(),
                        "accounts": [
                            str(account_keys[acc_idx]) for acc_idx in ix.accounts
                        ],
                        "program": program_id,
                    }
                )
        else:
            instruction_name = "External"
            if program_id == "ComputeBudget111111111111111111111111111111":
                if ix.data[:1] == b"\x03":
                    instruction_name = "ComputeBudget: Set compute unit limit"
                elif ix.data[:1] == b"\x02":
                    instruction_name = "ComputeBudget: Set compute unit price"
            elif program_id == "ATokenGPvbdGVxr1b2hvZbsiqW5xWH25efTNsLJA8knL":
                instruction_name = "Associated Token Account: Create"

            decoded_instructions.append(
                {
                    "name": instruction_name,
                    "programId": program_id,
                    "data": bytes(ix.data).hex(),
                    "accounts": [str(account_keys[acc_idx]) for acc_idx in ix.accounts],
                }
            )

    return decoded_instructions


tx_file_path = ""

if len(sys.argv) != 2:
    tx_file_path = "learning-examples/blocksubscribe-transactions/raw_create_tx_from_blocksubscribe.json"
    print(f"No path provided, using the path: {tx_file_path}")
else:
    tx_file_path = sys.argv[1]

idl = load_idl("idl/pump_fun_idl.json")
tx_data = load_transaction(tx_file_path)

decoded_instructions = decode_transaction(tx_data, idl)
print(json.dumps(decoded_instructions, indent=2))