# -*- coding: utf-8 -*-

import ast

import re

import sys

import time

from ipykernel.kernelbase import Kernel

from .board import connect

__version__ = '0.1.0'

class CircuitPyKernel(Kernel):

implementation = 'circuitpython_kernel'

implementation_version = '0.1.0'

language_info = {'name': 'python',

'version': '3',

'mimetype': 'text/x-python',

'file_extension': '.py',

'codemirror_mode': {'name': 'python',

'version': 3},

'pygments_lexer': 'python3',

}

help_links = [

{'text': 'CircuitPython kernel',

'url': 'http://github.com/willingc/circuitpython_kernel.git'

},

]

banner = "Jupyter and CircuitPython create fablab-ulous things."

def __init__(self, **kwargs):

"""Set up connection to board"""

super().__init__(**kwargs)

self.serial = connect()

def run_code(self, code):

"""Run a string of code, return strings for stdout and stderr"""

self.serial.write(code.encode('utf-8') + b'\x04')

result = bytearray()

while not result.endswith(b'\x04>'):

time.sleep(0.1)

result.extend(self.serial.read_all())

assert result.startswith(b'OK')

out, err = result[2:-2].split(b'\x04', 1)

return out.decode('utf-8', 'replace'), err.decode('utf-8', 'replace')

def do_execute(self, code, silent, store_history=True,

user_expressions=None, allow_stdin=False):

"""Execute a user's code cell"""

out, err = self.run_code(code)

if out:

self.send_response(self.iopub_socket, 'stream', {

'name': 'stdout',

'text': out

})

if err:

self.send_response(self.iopub_socket, 'stream', {

'name': 'stderr',

'text': err

})

return {'status': 'ok', 'execution_count': self.execution_count,

'payload': [], 'user_expressions': {}}

def _eval(self, expr):

"""Evaluate the expression"""

out, err = self.run_code('print({})'.format(expr))

return ast.literal_eval(out)

def do_complete(self, code, cursor_pos):

"""Support code completion"""

code = code[:cursor_pos]

m = re.search(r'(\w+\.)*(\w+)?$', code)

if m:

prefix = m.group()

if '.' in prefix:

obj, prefix = prefix.rsplit('.')

names = self._eval('dir({})'.format(obj))

else:

names = self._eval('dir()')

matches = [n for n in names if n.startswith(prefix)]

return {'matches': matches,

'cursor_start': cursor_pos - len(prefix), 'cursor_end': cursor_pos,

'metadata': {}, 'status': 'ok'}

else:

return {'matches': [],

'cursor_start': cursor_pos, 'cursor_end': cursor_pos,

'metadata': {}, 'status': 'ok'}