# -----------------------------------------------------------------------------
#  Copyright (C) Jupyter Development Team
#
#  Distributed under the terms of the BSD License.  The full license is in
#  the file COPYING, distributed as part of this software.
# -----------------------------------------------------------------------------
import json

from tornado.log import access_log
from tornado.web import StaticFileHandler


def log_request(handler):
    """log a bit more information about each request than tornado's default
    
    - move static file get success to debug-level (reduces noise)
    - get proxied IP instead of proxy IP
    - log referer for redirect and failed requests
    - log user-agent for failed requests
    """
    status = handler.get_status()
    request = handler.request
    if (
        status == 304
        or (status < 300 and isinstance(handler, StaticFileHandler))
        or (status < 300 and request.uri == "/")
    ):
        # static-file successes or any 304 FOUND are debug-level
        log_method = access_log.debug
    elif status < 400:
        log_method = access_log.info
    elif status < 500:
        log_method = access_log.warning
    else:
        log_method = access_log.error

    request_time = 1000.0 * handler.request.request_time()
    ns = dict(
        status=status,
        method=request.method,
        ip=request.remote_ip,
        uri=request.uri,
        request_time=request_time,
    )
    msg = "{status} {method} {uri} ({ip}) {request_time:.2f}ms"
    if status >= 300:
        # log referers on redirects
        ns["referer"] = request.headers.get("Referer", "None")
        msg = msg + ' referer="{referer}"'
    if status >= 400:
        # log user agent for failed requests
        ns["agent"] = request.headers.get("User-Agent", "Unknown")
        msg = msg + ' user-agent="{agent}"'
    if status >= 500 and status not in {502, 503}:
        # log all headers if it caused an error
        log_method(json.dumps(dict(request.headers), indent=2))
    log_method(msg.format(**ns))