import requests
import json
import sys
from datetime import datetime

# --- Configuration ---
# The base URL for your mempool API instance.
BASE_URL = "https://mempool.mikoshi.de/api/tx/"

def format_transaction_details(tx_data):
    """Formats the JSON data from the API into a human-readable string."""
    
    txid = tx_data.get("txid", "N/A")
    fee = tx_data.get("fee", 0)
    size = tx_data.get("size", 0)
    weight = tx_data.get("weight", 0)
    
    # Status details
    status = tx_data.get("status", {})
    confirmed = status.get("confirmed", False)
    if confirmed:
        block_height = status.get("block_height", "N/A")
        block_time_unix = status.get("block_time", 0)
        block_time_str = datetime.utcfromtimestamp(block_time_unix).strftime('%Y-%m-%d %H:%M:%S UTC')
        status_str = f"✅ Confirmed in block {block_height} at {block_time_str}"
    else:
        status_str = "⌛ Unconfirmed"

    # --- Start building the output string ---
    output = []
    output.append("=" * 80)
    output.append(f"TRANSACTION DETAILS FOR: {txid}")
    output.append("=" * 80)

    # General Info
    output.append("\n--- General ---")
    output.append(f"Status: {status_str}")
    output.append(f"Fee: {fee} sats")
    output.append(f"Size: {size} bytes")
    output.append(f"Weight: {weight} vB")
    output.append(f"Fee Rate: {fee/(weight/4):.2f} sat/vB")

    # Inputs (vin)
    vin = tx_data.get("vin", [])
    output.append(f"\n--- Inputs ({len(vin)}) ---")
    if not vin:
        output.append("No inputs found (likely a coinbase transaction).")
    for i, an_input in enumerate(vin, 1):
        prev_txid = an_input.get("txid", "N/A")
        prev_vout = an_input.get("vout", "N/A")
        prevout = an_input.get("prevout", {})
        value = prevout.get("value", "N/A")
        address = prevout.get("scriptpubkey_address", "Address not available")
        output.append(f"  {i}. From TX: {prev_txid[:20]}... | Output Index: {prev_vout}")
        output.append(f"     Value: {value} sats | Spent by: {address}")

    # Outputs (vout)
    vout = tx_data.get("vout", [])
    output.append(f"\n--- Outputs ({len(vout)}) ---")
    for i, an_output in enumerate(vout, 1):
        value = an_output.get("value", "N/A")
        address = an_output.get("scriptpubkey_address", "Address not available")
        output.append(f"  {i}. Value: {value} sats | To Address: {address}")

    output.append("\n" * 2) # Add space before the next transaction
    return "\n".join(output)


def main():
    """Main function to run the script."""
    if len(sys.argv) != 3:
        print("Usage: python fetch_tx_details.py <input_file.txt> <output_file.txt>")
        sys.exit(1)

    input_filename = sys.argv[1]
    output_filename = sys.argv[2]

    try:
        with open(input_filename, 'r') as f:
            txids = [line.strip() for line in f if line.strip()]
    except FileNotFoundError:
        print(f"Error: Input file '{input_filename}' not found.")
        sys.exit(1)

    print(f"Found {len(txids)} transaction IDs. Fetching details...")

    with open(output_filename, 'w') as out_file:
        for i, txid in enumerate(txids):
            print(f"({i+1}/{len(txids)}) Fetching {txid}...")
            try:
                response = requests.get(f"{BASE_URL}{txid}", timeout=10)
                # Check if the request was successful
                if response.status_code == 200:
                    data = response.json()
                    formatted_data = format_transaction_details(data)
                    out_file.write(formatted_data)
                else:
                    error_message = f"Failed to fetch {txid}. Status Code: {response.status_code}. Response: {response.text}\n\n"
                    print(error_message)
                    out_file.write(error_message)
            except requests.RequestException as e:
                error_message = f"An error occurred while fetching {txid}: {e}\n\n"
                print(error_message)
                out_file.write(error_message)

    print(f"\n✅ Done! All details have been saved to '{output_filename}'.")


if __name__ == "__main__":
    main()