# -*- python -*-
import asyncio
import os
import re

class Plugin:
    _trim_regexp = re.compile("(`|\\$|\\.\\.)")
    _quote_regexp = re.compile("(\"|')")

    @classmethod
    def _trim(cls, s):
        result = cls._trim_regexp.sub("", s)
        result = cls._quote_regexp.sub("“", result).strip()
        return result

    # letter(ASCII or cyrillic), number, underscore only.
    _cmd_validator_regexp = re.compile("^(\\w|\\p{Cyrillic})*$")

    @asyncio.coroutine
    def _exec_cmd(self, cmd, body, nick, dir_path, is_admin):
        is_admin = "true" if is_admin else "false"
        path = os.path.join(dir_path, self._trim(cmd))

        if not self._cmd_validator_regexp.match(cmd) or \
           not os.access(path, os.F_OK | os.X_OK) or not os.path.isfile(path):
            return {"handled": False}

        if not os.access(path, os.R_OK):
            return {"handled": True,
                    "error": "\"%s\" is not readable" % path}

        cmd = [path, self._trim(nick), is_admin, self._trim(body)]
        try:
            pipe = asyncio.subprocess.PIPE
            proc = yield from asyncio.create_subprocess_exec(*cmd,
                                                             stdout=pipe,
                                                             stderr=pipe)
            cmd_reply, cmd_error = yield from proc.communicate()
        except OSError as e:
            return {"handled": True,
                    "error": "Execute: %s" % str(e)}

        result = {}
        if cmd_error and len(cmd_error.strip()) > 0:
            result["error"] = "Process: %s" % cmd_error.strip()
        if cmd_reply and len(cmd_reply.strip()) > 0:
            result["reply"] = cmd_reply.decode().strip()
        if result:
            result["handled"] = True
        return result

    @asyncio.coroutine
    def command(self, command, body, nick, from_id, is_admin):
        result = yield from self._exec_cmd(command, body, nick,
                                           "plugins", is_admin)
        return result

    @asyncio.coroutine
    def question(self, body, nick, from_id, is_admin):
        result = yield from self._exec_cmd("answer", body, nick,
                                           "chat", is_admin)
        return result