#!/usr/bin/env python

import warnings
warnings.filterwarnings('ignore', 'libevent')
import gevent.monkey
gevent.monkey.patch_all(thread=False)

import copy
import datetime
import errno
import httplib
import json
import os
from os import path
import traceback
import urlparse

import gevent.pywsgi

import fileio
import reloader

DATA_DIR = path.expanduser('~/sysvitals_data')
handlers = None

def main():
	global handlers
	handlers = {
		'data': get_data,
		'datum': post_datum,
	}
	server = gevent.pywsgi.WSGIServer(('0.0.0.0', 8892), application)
	reloader.init(server)
	server.serve_forever()

class HTTPException(Exception):
	def __init__(self, code, body):
		self.code = code
		self.body = body

def application(environ, start_response):
	try:
		split = environ['PATH_INFO'][1:].split('/')
		qs = environ['QUERY_STRING']
		if qs:
			query = urlparse.parse_qs(qs, True, True)
			for k, v in query.items():
				if len(v) > 1:
					raise HTTPException(400, 'duplicate query parameter: ' + k)
				query[k] = v[0]
		else:
			query = {}
		if split[0] == 'v1':
			handler = handlers.get(split[2])
			if handler:
				body = json.dumps(handler(split, query, environ))
				start_response('200 OK', [('Content-type', 'application/json')])
				return [body]
			else:
				print 'no handler for', split
		else:
			print 'split was', split
		raise HTTPException(404, 'unhandled path: ' + environ['PATH_INFO'])
	except HTTPException as e:
		response = '%d %s' % (e.code, httplib.responses[e.code])
		start_response(response, [('Content-type', 'text/plain')])
		return [e.body]
	except:
		traceback.print_exc()
		start_response('500 Internal Server Error', [('Content-type', 'text/plain')])
		return ['ruh roh']

def get_data(split, query, environ):
	try:
		group = int(split[1])
		server_id = int(split[3])
		start = datetime.datetime.strptime(query['start'], '%Y-%m-%d').date()
		end = datetime.datetime.strptime(query['end'], '%Y-%m-%d').date()
	except (IndexError, KeyError, ValueError):
		raise HTTPException(400, '')

	server_dir = path.join(DATA_DIR, str(group), str(server_id))
	rval = {}
	c = start
	while c <= end:
		date_str = c.isoformat()
		try:
			with open(path.join(server_dir, date_str), 'r') as f:
				stats = fileio.read_stats(f)
		except IOError as e:
			if e.errno == errno.ENOENT:
				stats = None
			else:
				raise
		rval[date_str] = stats
		c += datetime.timedelta(days=1)
	return rval

def post_datum(split, query, environ):
	try:
		group = int(split[1])
		server_id = int(split[3])
	except (IndexError, ValueError):
		raise HTTPException(400, '')
	try:
		body = json.load(environ['wsgi.input'])
	except ValueError:
		raise HTTPException(400, 'post body was not valid JSON')
	if not isinstance(body, dict):
		raise HTTPException(400, 'post body was not a JSON dictionary')
	if body.keys() != fileio.TEMPLATE.keys():
		diff = set(body.keys()).symmetric_difference(set(fileio.TEMPLATE.keys()))
		raise HTTPException(400, 'post body had missing or extra keys: ' + ','.join(diff))

	server_dir = path.join(DATA_DIR, str(group), str(server_id))
	try:
		os.makedirs(server_dir)
	except OSError as e:
		if e.errno != errno.EEXIST:
			raise

	# we floor to the minute, so this rounds to the nearest minute
	now = datetime.datetime.utcnow() + datetime.timedelta(seconds=29)
	data_path = path.join(server_dir, now.date().isoformat())
	try:
		with open(data_path, 'r') as f:
			stats = fileio.read_stats(f)
	except IOError as e:
		if e.errno != errno.ENOENT:
			raise
		stats = copy.deepcopy(fileio.TEMPLATE)

	index = now.hour * 60 + now.minute
	data = {}
	for field, subfields in stats.items():
		field_data = {}
		if field == 'disk':
			disk = stats['disk']
			for mountpoint, datum in body['disk'].items(): # iterate through body to get new mountpoints
				disk.setdefault(mountpoint, {'total': [-1] * 1440, 'used': [-1] * 1440})
				field_data[mountpoint] = {}
				for subfield, array in disk[mountpoint].items():
					array = list(array)
					array[index] = datum[subfield]
					field_data[mountpoint][subfield] = array
		else:
			for subfield, array in subfields.items():
				array = list(array)
				array[index] = body[field][subfield]
				field_data[subfield] = array
		data[field] = field_data

	with open(data_path, 'w') as f:
		fileio.write_datum(f, data)
	return {'status': 'ok'}

main()