#!/usr/bin/env python3
"""Monitor per-second interrupt counts for a specific interrupt type."""

import sys
import time


def parse_interrupts(filter_str):
    """Parse /proc/interrupts and return counts for lines matching filter_str."""
    results = {}
    with open("/proc/interrupts") as f:
        header = f.readline().split()
        num_cpus = len(header)
        for line in f:
            if filter_str not in line:
                continue
            parts = line.split()
            label = parts[0].rstrip(":")
            counts = [int(parts[i + 1]) for i in range(num_cpus)]
            results[label] = counts
    return header, results


def main():
    if len(sys.argv) < 2:
        print(f"Usage: {sys.argv[0]} <interrupt-type>", file=sys.stderr)
        sys.exit(1)

    filter_str = sys.argv[1]
    cpu_names, prev = parse_interrupts(filter_str)

    if not prev:
        print(f"No interrupts matching '{filter_str}' found in /proc/interrupts", file=sys.stderr)
        sys.exit(1)

    num_cpus = len(cpu_names)
    print(f"Monitoring interrupts matching '{filter_str}' every 1s (Ctrl-C to stop)\n")

    # Print header
    cpu_hdr = "  ".join(f"{c:>8}" for c in cpu_names)
    print(f"{'IRQ':<20}  {cpu_hdr}  {'TOTAL':>10}")
    print("-" * (22 + num_cpus * 10 + 12))

    try:
        while True:
            time.sleep(1)
            _, curr = parse_interrupts(filter_str)
            for label in sorted(curr):
                if label not in prev:
                    prev[label] = [0] * num_cpus
                deltas = [c - p for c, p in zip(curr[label], prev[label])]
                total = sum(deltas)
                cols = "  ".join(f"{d:>8}" for d in deltas)
                print(f"{label:<20}  {cols}  {total:>10}")
            prev = curr
    except KeyboardInterrupt:
        print()


if __name__ == "__main__":
    main()