#!/usr/bin/env python3
"""
test_integration.py - Integration tests for mod_reqin_log

This script runs integration tests for the mod_reqin_log Apache module.
It tests the 4 required scenarios from architecture.yml:
1. basic_logging - Verify JSON logs with expected fields
2. header_limits - Verify header count and value length limits
3. socket_unavailable_on_start - Verify reconnect behavior when socket is unavailable
4. runtime_socket_loss - Verify behavior when socket disappears during traffic
"""

import socket
import os
import sys
import json
import signal
import time
import subprocess
import threading
import argparse
from datetime import datetime
from http.server import HTTPServer, BaseHTTPRequestHandler

# Default paths
DEFAULT_SOCKET_PATH = "/tmp/mod_reqin_log_test.sock"
DEFAULT_APACHE_URL = "http://localhost:8080"

# Test results
tests_run = 0
tests_passed = 0
tests_failed = 0

# Global flags
shutdown_requested = False
log_entries = []
socket_server = None
socket_thread = None


def log_info(msg):
    print(f"[INFO] {msg}", file=sys.stderr)


def log_pass(msg):
    global tests_passed
    tests_passed += 1
    print(f"[PASS] {msg}", file=sys.stderr)


def log_fail(msg):
    global tests_failed
    tests_failed += 1
    print(f"[FAIL] {msg}", file=sys.stderr)


def log_test_start(name):
    global tests_run
    tests_run += 1
    print(f"\n[TEST] Starting: {name}", file=sys.stderr)


class SocketServer:
    """Unix socket server that collects JSON log entries."""
    
    def __init__(self, socket_path):
        self.socket_path = socket_path
        self.server = None
        self.running = False
        self.entries = []
        self.lock = threading.Lock()
        self.connection = None
        self.buffer = b""
        
    def start(self):
        """Start the socket server."""
        # Remove existing socket
        if os.path.exists(self.socket_path):
            os.remove(self.socket_path)
        
        # Create socket
        self.server = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
        self.server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        self.server.bind(self.socket_path)
        self.server.listen(5)
        self.server.settimeout(1.0)
        os.chmod(self.socket_path, 0o666)
        self.running = True
        
        # Start accept thread
        self.thread = threading.Thread(target=self._accept_loop, daemon=True)
        self.thread.start()
        
    def _accept_loop(self):
        """Accept connections and read data."""
        while self.running:
            try:
                conn, addr = self.server.accept()
                conn.settimeout(0.5)
                self.connection = conn
                while self.running:
                    try:
                        chunk = conn.recv(4096)
                        if not chunk:
                            break
                        self.buffer += chunk
                        
                        # Process complete lines
                        while b'\n' in self.buffer:
                            newline_pos = self.buffer.index(b'\n')
                            line = self.buffer[:newline_pos].decode('utf-8', errors='replace')
                            self.buffer = self.buffer[newline_pos + 1:]
                            if line.strip():
                                self._process_entry(line)
                    except socket.timeout:
                        continue
                    except Exception as e:
                        break
                conn.close()
                self.connection = None
            except socket.timeout:
                continue
            except Exception as e:
                if self.running:
                    log_info(f"Socket server error: {e}")
                    
    def _process_entry(self, line):
        """Process a log entry."""
        try:
            entry = json.loads(line)
            with self.lock:
                self.entries.append(entry)
        except json.JSONDecodeError:
            log_info(f"Invalid JSON entry: {line[:100]}")
            
    def stop(self):
        """Stop the socket server."""
        self.running = False
        if self.connection:
            try:
                self.connection.close()
            except:
                pass
        if self.server:
            try:
                self.server.close()
            except:
                pass
        if os.path.exists(self.socket_path):
            try:
                os.remove(self.socket_path)
            except:
                pass
                
    def get_entries(self):
        """Get collected log entries."""
        with self.lock:
            return list(self.entries)
            
    def clear_entries(self):
        """Clear collected entries."""
        with self.lock:
            self.entries.clear()
            
    def wait_for_entries(self, count, timeout=5.0):
        """Wait for at least 'count' entries to arrive."""
        start = time.time()
        while time.time() - start < timeout:
            with self.lock:
                if len(self.entries) >= count:
                    return True
            time.sleep(0.1)
        return False


def make_request(url, headers=None, method='GET'):
    """Make an HTTP request using curl."""
    import urllib.request
    
    req = urllib.request.Request(url, method=method)
    if headers:
        for key, value in headers.items():
            req.add_header(key, value)
    
    try:
        with urllib.request.urlopen(req, timeout=5) as response:
            return response.status, response.read().decode('utf-8', errors='replace')
    except Exception as e:
        return None, str(e)


# ============================================================================
# Test 1: Basic Logging
# ============================================================================
def test_basic_logging(socket_server, apache_url):
    """
    Test: basic_logging
    Description: With JsonSockLogEnabled On and valid socket, verify that each request
                 produces a valid JSON line with expected fields.
    """
    log_test_start("basic_logging")
    
    socket_server.clear_entries()
    
    # Make a simple request
    status, _ = make_request(f"{apache_url}/")
    
    # Wait for log entry
    if not socket_server.wait_for_entries(1, timeout=3.0):
        log_fail("basic_logging - No log entries received")
        return False
    
    entries = socket_server.get_entries()
    entry = entries[-1]
    
    # Verify required fields
    required_fields = ['time', 'timestamp', 'src_ip', 'src_port', 'dst_ip', 
                       'dst_port', 'method', 'path', 'host', 'http_version']
    
    missing_fields = []
    for field in required_fields:
        if field not in entry:
            missing_fields.append(field)
    
    if missing_fields:
        log_fail(f"basic_logging - Missing fields: {missing_fields}")
        return False
    
    # Verify field types and values
    if entry.get('method') != 'GET':
        log_fail(f"basic_logging - Expected method 'GET', got '{entry.get('method')}'")
        return False
    
    if not isinstance(entry.get('timestamp'), int):
        log_fail(f"basic_logging - timestamp should be integer, got {type(entry.get('timestamp'))}")
        return False
    
    if not entry.get('time', '').startswith('20'):
        log_fail(f"basic_logging - Invalid time format: {entry.get('time')}")
        return False
    
    log_pass("basic_logging - All required fields present and valid")
    return True


# ============================================================================
# Test 2: Header Limits
# ============================================================================
def test_header_limits(socket_server, apache_url):
    """
    Test: header_limits
    Description: Configure more headers than JsonSockLogMaxHeaders and verify only
                 the first N are logged and values are truncated.
    """
    log_test_start("header_limits")
    
    socket_server.clear_entries()
    
    # Make request with multiple headers including a long one
    headers = {
        'X-Request-Id': 'test-123',
        'X-Trace-Id': 'trace-456',
        'User-Agent': 'TestAgent/1.0',
        'X-Long-Header': 'A' * 500,  # Very long value
    }
    
    status, _ = make_request(f"{apache_url}/test-headers", headers=headers)
    
    # Wait for log entry
    if not socket_server.wait_for_entries(1, timeout=3.0):
        log_fail("header_limits - No log entries received")
        return False
    
    entries = socket_server.get_entries()
    entry = entries[-1]
    
    # Check that header fields are present (implementation logs configured headers)
    header_fields = [k for k in entry.keys() if k.startswith('header_')]
    
    # Verify header value truncation (max 256 chars by default)
    for key, value in entry.items():
        if key.startswith('header_') and isinstance(value, str):
            if len(value) > 256:
                log_fail(f"header_limits - Header value not truncated: {key} has {len(value)} chars")
                return False
    
    log_pass(f"header_limits - Headers logged correctly ({len(header_fields)} header fields)")
    return True


# ============================================================================
# Test 3: Socket Unavailable on Start
# ============================================================================
def test_socket_unavailable_on_start(socket_server, apache_url):
    """
    Test: socket_unavailable_on_start
    Description: Start with socket not yet created; verify periodic reconnect attempts
                 and throttled error logging.
    """
    log_test_start("socket_unavailable_on_start")
    
    # Stop the socket server to simulate unavailable socket
    socket_server.stop()
    time.sleep(0.5)
    
    # Make requests while socket is unavailable
    for i in range(3):
        make_request(f"{apache_url}/unavailable-{i}")
        time.sleep(0.2)
    
    # Requests should still succeed (logging failures don't affect client)
    status, _ = make_request(f"{apache_url}/final-check")
    if status != 200:
        log_fail("socket_unavailable_on_start - Request failed when socket unavailable")
        # Restart socket server for subsequent tests
        socket_server.start()
        return False
    
    # Restart socket server
    socket_server.start()
    time.sleep(0.5)
    
    # Verify module can reconnect
    socket_server.clear_entries()
    status, _ = make_request(f"{apache_url}/after-reconnect")
    
    if socket_server.wait_for_entries(1, timeout=3.0):
        log_pass("socket_unavailable_on_start - Module reconnected after socket became available")
        return True
    else:
        log_fail("socket_unavailable_on_start - Module did not reconnect")
        return False


# ============================================================================
# Test 4: Runtime Socket Loss
# ============================================================================
def test_runtime_socket_loss(socket_server, apache_url):
    """
    Test: runtime_socket_loss
    Description: Drop the Unix socket while traffic is ongoing; verify that log lines
                 are dropped, worker threads are not blocked, and reconnect attempts
                 resume once the socket reappears.
    """
    log_test_start("runtime_socket_loss")
    
    socket_server.clear_entries()
    
    # Make some initial requests
    for i in range(3):
        make_request(f"{apache_url}/before-loss-{i}")
    
    if not socket_server.wait_for_entries(3, timeout=3.0):
        log_fail("runtime_socket_loss - Initial requests not logged")
        return False
    
    initial_count = len(socket_server.get_entries())
    
    # Simulate socket loss by stopping server
    socket_server.stop()
    time.sleep(0.3)
    
    # Make requests while socket is gone
    start_time = time.time()
    for i in range(3):
        req_start = time.time()
        status, _ = make_request(f"{apache_url}/during-loss-{i}")
        req_duration = time.time() - req_start
        
        # Requests should NOT block (should complete quickly)
        if req_duration > 2.0:
            log_fail(f"runtime_socket_loss - Request blocked for {req_duration:.2f}s")
            socket_server.start()
            return False
    
    # Give time for any pending logs
    time.sleep(0.5)
    
    # Verify no new entries were logged (socket was down)
    current_count = len(socket_server.get_entries())
    if current_count != initial_count:
        log_info(f"runtime_socket_loss - Some entries logged during socket loss (expected: {initial_count}, got: {current_count})")
    
    # Restart socket server
    socket_server.start()
    time.sleep(0.5)
    
    # Verify module can reconnect and log again
    socket_server.clear_entries()
    status, _ = make_request(f"{apache_url}/after-loss")
    
    if socket_server.wait_for_entries(1, timeout=3.0):
        log_pass("runtime_socket_loss - Module recovered after socket restored")
        return True
    else:
        log_fail("runtime_socket_loss - Module did not recover after socket restored")
        return False


# ============================================================================
# Main Test Runner
# ============================================================================
def run_all_tests(apache_url, socket_path):
    """Run all integration tests."""
    global tests_run, tests_passed, tests_failed
    
    print("=" * 60, file=sys.stderr)
    print("mod_reqin_log Integration Tests", file=sys.stderr)
    print("=" * 60, file=sys.stderr)
    
    # Create socket server
    server = SocketServer(socket_path)
    server.start()
    log_info(f"Socket server started on {socket_path}")
    
    # Give Apache time to connect
    time.sleep(1.0)
    
    try:
        # Run all tests
        test_basic_logging(server, apache_url)
        test_header_limits(server, apache_url)
        test_socket_unavailable_on_start(server, apache_url)
        test_runtime_socket_loss(server, apache_url)
        
    finally:
        # Cleanup
        server.stop()
        log_info("Socket server stopped")
    
    # Print summary
    print("\n" + "=" * 60, file=sys.stderr)
    print("Test Summary", file=sys.stderr)
    print("=" * 60, file=sys.stderr)
    print(f"Tests run:    {tests_run}", file=sys.stderr)
    print(f"Tests passed: {tests_passed}", file=sys.stderr)
    print(f"Tests failed: {tests_failed}", file=sys.stderr)
    print("=" * 60, file=sys.stderr)
    
    return tests_failed == 0


def main():
    parser = argparse.ArgumentParser(description='Integration tests for mod_reqin_log')
    parser.add_argument('--socket', default=DEFAULT_SOCKET_PATH,
                        help=f'Unix socket path (default: {DEFAULT_SOCKET_PATH})')
    parser.add_argument('--url', default=DEFAULT_APACHE_URL,
                        help=f'Apache URL (default: {DEFAULT_APACHE_URL})')
    args = parser.parse_args()
    
    success = run_all_tests(args.url, args.socket)
    sys.exit(0 if success else 1)


if __name__ == '__main__':
    main()