# -*- coding: utf-8 -*-
# Copyright (c) 2015, Maxwell Morais and contributors
# For license information, please see license.txt

from __future__ import unicode_literals

import frappe
from frappe.utils import cstr, encode
import os
import sys
import inspect
import traceback
import linecache
import pydoc
import cgitb
import types
import datetime
import json
import six

def make_error_snapshot(exception):
	if frappe.conf.disable_error_snapshot:
		return

	logger = frappe.logger(__name__, with_more_info=False)

	try:
		error_id = '{timestamp:s}-{ip:s}-{hash:s}'.format(
			timestamp=cstr(datetime.datetime.now()),
			ip=frappe.local.request_ip or '127.0.0.1',
			hash=frappe.generate_hash(length=3)
		)
		snapshot_folder = get_error_snapshot_path()
		frappe.create_folder(snapshot_folder)

		snapshot_file_path = os.path.join(snapshot_folder, "{0}.json".format(error_id))
		snapshot = get_snapshot(exception)

		with open(encode(snapshot_file_path), 'wb') as error_file:
			error_file.write(encode(frappe.as_json(snapshot)))

		logger.error('New Exception collected with id: {}'.format(error_id))

	except Exception as e:
		logger.error('Could not take error snapshot: {0}'.format(e), exc_info=True)

def get_snapshot(exception, context=10):
	"""
	Return a dict describing a given traceback (based on cgitb.text)
	"""

	etype, evalue, etb = sys.exc_info()
	if isinstance(etype, six.class_types):
		etype = etype.__name__

	# creates a snapshot dict with some basic information

	s = {
		'pyver': 'Python {version:s}: {executable:s} (prefix: {prefix:s})'.format(
			version = sys.version.split()[0],
			executable = sys.executable,
			prefix = sys.prefix
		),
		'timestamp': cstr(datetime.datetime.now()),
		'traceback': traceback.format_exc(),
		'frames': [],
		'etype': cstr(etype),
		'evalue': cstr(repr(evalue)),
		'exception': {},
		'locals': {}
	}

	# start to process frames
	records = inspect.getinnerframes(etb, 5)

	for frame, file, lnum, func, lines, index in records:
		file = file and os.path.abspath(file) or '?'
		args, varargs, varkw, locals = inspect.getargvalues(frame)
		call = ''

		if func != '?':
			call = inspect.formatargvalues(args, varargs, varkw, locals, formatvalue=lambda value: '={}'.format(pydoc.text.repr(value)))

		# basic frame information
		f = {'file': file, 'func': func, 'call': call, 'lines': {}, 'lnum': lnum}

		def reader(lnum=[lnum]):
			try:
				return linecache.getline(file, lnum[0])
			finally:
				lnum[0] += 1

		vars = cgitb.scanvars(reader, frame, locals)

		# if it is a view, replace with generated code
		# if file.endswith('html'):
		# 	lmin = lnum > context and (lnum - context) or 0
		# 	lmax = lnum + context
		# 	lines = code.split("\n")[lmin:lmax]
		# 	index = min(context, lnum) - 1

		if index is not None:
			i = lnum - index
			for line in lines:
				f['lines'][i] = line.rstrip()
				i += 1

		# dump local variable (referenced in current line only)
		f['dump'] = {}
		for name, where, value in vars:
			if name in f['dump']:
				continue
			if value is not cgitb.__UNDEF__:
				if where == 'global':
					name = 'global {name:s}'.format(name=name)
				elif where != 'local':
					name = where + ' ' + name.split('.')[-1]
				f['dump'][name] = pydoc.text.repr(value)
			else:
				f['dump'][name] = 'undefined'

		s['frames'].append(f)

	# add exception type, value and attributes
	if isinstance(evalue, BaseException):
		for name in dir(evalue):
			# prevent py26 DeprecationWarning
			if (name != 'messages' or sys.version_info < (2.6)) and not name.startswith('__'):
				value = pydoc.text.repr(getattr(evalue, name))

				# render multilingual string properly
				if type(value)==str and value.startswith(b"u'"):
					value = eval(value)

				s['exception'][name] = encode(value)

	# add all local values (of last frame) to the snapshot
	for name, value in locals.items():
		if type(value)==str and value.startswith(b"u'"):
			value = eval(value)

		s['locals'][name] = pydoc.text.repr(value)

	return s

def collect_error_snapshots():
	"""Scheduled task to collect error snapshots from files and push into Error Snapshot table"""
	if frappe.conf.disable_error_snapshot:
		return

	try:
		path = get_error_snapshot_path()
		if not os.path.exists(path):
			return

		for fname in os.listdir(path):
			fullpath = os.path.join(path, fname)

			try:
				with open(fullpath, 'r') as filedata:
					data = json.load(filedata)

			except ValueError:
				# empty file
				os.remove(fullpath)
				continue

			for field in ['locals', 'exception', 'frames']:
				data[field] = frappe.as_json(data[field])

			doc = frappe.new_doc('Error Snapshot')
			doc.update(data)
			doc.save()

			frappe.db.commit()

			os.remove(fullpath)

		clear_old_snapshots()

	except Exception as e:
		make_error_snapshot(e)

		# prevent creation of unlimited error snapshots
		raise

def clear_old_snapshots():
	"""Clear snapshots that are older than a month"""
	frappe.db.sql("""delete from `tabError Snapshot`
		where creation < date_sub(now(), interval 1 month)""")

	path = get_error_snapshot_path()
	today = datetime.datetime.now()

	for file in os.listdir(path):
		p = os.path.join(path, file)
		ctime = datetime.datetime.fromtimestamp(os.path.getctime(p))
		if (today - ctime).days > 31:
			os.remove(os.path.join(path, p))

def get_error_snapshot_path():
	return frappe.get_site_path('error-snapshots')