from ConfigParser import ConfigParser

import signal

from functools import partial

from validate import vInteger

from error import NeededOption 

class MyConfigParser(ConfigParser):

    def __init__(self):

        ConfigParser.__init__(self)

        self.reloadList=[]

    def read(self,files):

        from offer import getProvider

        r = ConfigParser.read(self, files)

        for s in self.sections():

            if s == "main":

                main.validate(self.items(s))

            else:

                getProvider("tmp", self.get(s,'typ'), self.items(s))

        return r

    def reload_(self):

        for f in self.reloadList:

            f()

    def registerReload(self, func):

        self.reloadList.append(func)

class Option():

    def __init__(self, validate, long="", help="", must=False, default=None):

        self.validate = validate

        self.long=long

        self.help = help

        self.must = must

        self.default = default

class Config:

    def __init__(self, name):

        self.name = name

        self.options={

            "port":Option(partial(vInteger,minv=0),long="Port under that twisted is running",must=True),

            "dburl":Option(lambda x,y:x,long="Connection URL to database",must=True),

        }

        self.order = ["dburl","port"]

    def _read(self, cfg, write=False):

        c = dict(cfg)

        for o in self.options:

            option = self.options[o]

            try:

                value = option.validate(c[o],o)

                if write:

                    setattr(self,o,value)

            except KeyError:

                if option.must:

                    raise NeededOption(self.name, o)

                elif write and option.default is not None:

                    setattr(self, o, option.default)

    def validate(self, cfg):

        self._read(cfg, False)

    def load(self, cfg):

        self._read(cfg, True)

    def same(self, other):

        for o in self.options:

            if getattr(self,o) != getattr(other,o):

                return False

        else:

            return True

    def sampleConf(self):

        ret=[]

        for o in self.order:

            opt=self.options[o]

            if opt.long:

                ret.append("# "+opt.long)

            if opt.must:

                s= "%s = "%o

                if opt.default is not None:

                    s += str(opt.default)

                ret.append(s)

            else:

                ret.append("# %s = %s"%(o,opt.default))

            ret.append("")

        return ["[%s]"%self.name,]+ret

def readConfig():

    configParser.read(confFiles)

    if main._init:

        main.load(configParser.items("main"))

    else:

        m = Config("main")

        m.load(configParser.items("main"))

        if not main.same(m):

            raise Exception("Main options can't be reloaded, please restart your Application.")

def registerSignal():

    '''register readConfig to SIGUSR2'''

    def rC(signal, frame):

        readConfig()

    signal.signal(signal.SIGUSR2,rC)

configParser = MyConfigParser()

confFiles=["iro.conf", "~/iro.conf","/etc/iro/iro.conf"]

main = Config("main")