#!/usr/bin/env python3
"""Extract timestamp values from AT Protocol TID strings."""

import datetime

# Base32-sortable alphabet used by TIDs
BASE32_SORTABLE = "234567abcdefghijklmnopqrstuvwxyz"


def tid_to_timestamp(tid: str) -> int:
    """Convert a TID string to microseconds since UNIX epoch."""
    if len(tid) != 13:
        raise ValueError(f"TID must be 13 characters, got {len(tid)}")
    
    # Decode base32-sortable to integer
    value = 0
    for char in tid:
        idx = BASE32_SORTABLE.find(char)
        if idx == -1:
            raise ValueError(f"Invalid character in TID: {char!r}")
        value = value * 32 + idx
    
    # Extract timestamp (top 54 bits, but bit 63 is always 0, so really 53 bits)
    # The bottom 10 bits are the clock identifier
    timestamp_us = value >> 10
    
    return timestamp_us


def tid_to_datetime(tid: str) -> datetime.datetime:
    """Convert a TID string to a datetime object (UTC)."""
    timestamp_us = tid_to_timestamp(tid)
    return datetime.datetime.fromtimestamp(timestamp_us / 1_000_000, tz=datetime.timezone.utc)


if __name__ == "__main__":
    import sys
    
    if len(sys.argv) < 2:
        print(f"Usage: {sys.argv[0]} <tid> [tid ...]")
        print(f"Example: {sys.argv[0]} 3jzfcijpj2z2a")
        sys.exit(1)
    
    for tid in sys.argv[1:]:
        try:
            ts_us = tid_to_timestamp(tid)
            dt = tid_to_datetime(tid)
            print(f"{tid} -> {ts_us} µs -> {dt.isoformat()}")
        except ValueError as e:
            print(f"{tid} -> Error: {e}", file=sys.stderr)