import functools
import traceback
import time
import inspect
import os
import SocketServer

import django
from django.conf import settings

import pymongo
import pymongo.collection
import pymongo.cursor

__all__ = ['queries', 'inserts', 'updates', 'removes', 'install_tracker',
           'uninstall_tracker', 'reset']


_original_methods = {
    'insert': pymongo.collection.Collection.insert,
    'update': pymongo.collection.Collection.update,
    'remove': pymongo.collection.Collection.remove,
    'refresh': pymongo.cursor.Cursor._refresh,
}

queries = []
inserts = []
updates = []
removes = []

WANT_STACK_TRACE = getattr(settings, 'DEBUG_TOOLBAR_MONGO_STACKTRACES', True)
def _get_stacktrace():
    if WANT_STACK_TRACE:
        return _tidy_stacktrace(reversed(inspect.stack()))
    else:
        return []


# Wrap Cursor._refresh for getting queries
@functools.wraps(_original_methods['insert'])
def _insert(collection_self, doc_or_docs, manipulate=True,
           safe=False, check_keys=True, **kwargs):
    start_time = time.time()
    result = _original_methods['insert'](
        collection_self,
        doc_or_docs,
        manipulate=manipulate,
        safe=safe,
        check_keys=check_keys,
        **kwargs
    )
    total_time = (time.time() - start_time) * 1000

    __traceback_hide__ = True
    inserts.append({
        'document': doc_or_docs,
        'safe': safe,
        'time': total_time,
        'stack_trace': _get_stacktrace(),
    })
    return result

# Wrap Cursor._refresh for getting queries
@functools.wraps(_original_methods['update'])
def _update(collection_self, spec, document, upsert=False,
           maniuplate=False, safe=False, multi=False, **kwargs):
    start_time = time.time()
    result = _original_methods['update'](
        collection_self,
        spec,
        document,
        upsert=upsert,
        safe=safe,
        multi=multi,
        **kwargs
    )
    total_time = (time.time() - start_time) * 1000

    __traceback_hide__ = True
    updates.append({
        'document': document,
        'upsert': upsert,
        'multi': multi,
        'spec': spec,
        'safe': safe,
        'time': total_time,
        'stack_trace': _get_stacktrace(),
    })
    return result

# Wrap Cursor._refresh for getting queries
@functools.wraps(_original_methods['remove'])
def _remove(collection_self, spec_or_id, safe=False, **kwargs):
    start_time = time.time()
    result = _original_methods['remove'](
        collection_self,
        spec_or_id,
        safe=safe,
        **kwargs
    )
    total_time = (time.time() - start_time) * 1000

    __traceback_hide__ = True
    removes.append({
        'spec_or_id': spec_or_id,
        'safe': safe,
        'time': total_time,
        'stack_trace': _get_stacktrace(),
    })
    return result

# Wrap Cursor._refresh for getting queries
@functools.wraps(_original_methods['refresh'])
def _cursor_refresh(cursor_self):
    # Look up __ private instance variables
    def privar(name):
        return getattr(cursor_self, '_Cursor__{0}'.format(name))

    if privar('id') is not None:
        # getMore not query - move on
        return _original_methods['refresh'](cursor_self)

    # NOTE: See pymongo/cursor.py+557 [_refresh()] and
    # pymongo/message.py for where information is stored

    # Time the actual query
    start_time = time.time()
    result = _original_methods['refresh'](cursor_self)
    total_time = (time.time() - start_time) * 1000

    query_son = privar('query_spec')()

    __traceback_hide__ = True
    query_data = {
        'time': total_time,
        'operation': 'query',
        'stack_trace': _get_stacktrace(),
    }

    # Collection in format <db_name>.<collection_name>
    collection_name = privar('collection')
    query_data['collection'] = collection_name.full_name.split('.')[1]

    if query_data['collection'] == '$cmd':
        query_data['operation'] = 'command'
        # Handle count as a special case
        if 'count' in query_son:
            # Information is in a different format to a standar query
            query_data['collection'] = query_son['count']
            query_data['operation'] = 'count'
            query_data['skip'] = query_son.get('skip')
            query_data['limit'] = query_son.get('limit')
            query_data['query'] = query_son['query']
    else:
        # Normal Query
        query_data['skip'] = privar('skip')
        query_data['limit'] = privar('limit')
        query_data['query'] = query_son['$query']
        query_data['ordering'] = _get_ordering(query_son)

    queries.append(query_data)

    return result

def install_tracker():
    if pymongo.collection.Collection.insert != _insert:
        pymongo.collection.Collection.insert = _insert
    if pymongo.collection.Collection.update != _update:
        pymongo.collection.Collection.update = _update
    if pymongo.collection.Collection.remove != _remove:
        pymongo.collection.Collection.remove = _remove
    if pymongo.cursor.Cursor._refresh != _cursor_refresh:
        pymongo.cursor.Cursor._refresh = _cursor_refresh

def uninstall_tracker():
    if pymongo.collection.Collection.insert == _insert:
        pymongo.collection.Collection.insert = _original_methods['insert']
    if pymongo.collection.Collection.update == _update:
        pymongo.collection.Collection.update = _original_methods['update']
    if pymongo.collection.Collection.remove == _remove:
        pymongo.collection.Collection.remove = _original_methods['remove']
    if pymongo.cursor.Cursor._refresh == _cursor_refresh:
        pymongo.cursor.Cursor._refresh = _original_methods['cursor_refresh']

def reset():
    global queries, inserts, updates, removes
    queries = []
    inserts = []
    updates = []
    removes = []

def _get_ordering(son):
    """Helper function to extract formatted ordering from dict.
    """
    def fmt(field, direction):
        return '{0}{1}'.format({-1: '-', 1: '+'}[direction], field)

    if '$orderby' in son:
        return ', '.join(fmt(f, d) for f, d in son['$orderby'].items())

# Taken from Django Debug Toolbar 0.8.6
def _tidy_stacktrace(stack):
    """
    Clean up stacktrace and remove all entries that:
    1. Are part of Django (except contrib apps)
    2. Are part of SocketServer (used by Django's dev server)
    3. Are the last entry (which is part of our stacktracing code)

    ``stack`` should be a list of frame tuples from ``inspect.stack()``
    """
    django_path = os.path.realpath(os.path.dirname(django.__file__))
    django_path = os.path.normpath(os.path.join(django_path, '..'))
    socketserver_path = os.path.realpath(os.path.dirname(SocketServer.__file__))
    pymongo_path = os.path.realpath(os.path.dirname(pymongo.__file__))

    trace = []
    for frame, path, line_no, func_name, text in (f[:5] for f in stack):
        s_path = os.path.realpath(path)
        # Support hiding of frames -- used in various utilities that provide
        # inspection.
        if '__traceback_hide__' in frame.f_locals:
            continue
        if getattr(settings, 'DEBUG_TOOLBAR_CONFIG', {}).get('HIDE_DJANGO_SQL', True) \
            and django_path in s_path and not 'django/contrib' in s_path:
            continue
        if socketserver_path in s_path:
            continue
        if pymongo_path in s_path:
            continue
        if not text:
            text = ''
        else:
            text = (''.join(text)).strip()
        trace.append((path, line_no, func_name, text))
    return trace