import optparse
import sys
from typing import Any, Dict, List, Optional, Tuple, Union
from .pairtype import extendabletype

SUPPRESS_USAGE = optparse.SUPPRESS_USAGE

class AmbigousOptionError(Exception):
    pass

class NoMatchingOptionFound(AttributeError):
    pass

class ConfigError(Exception):
    pass

class ConflictConfigError(ConfigError):
    pass

class Config:
    _cfgimpl_frozen = False

    def __init__(self, descr, parent=None, **overrides):
        self._cfgimpl_descr = descr
        self._cfgimpl_value_owners: Dict[str, str] = {}
        self._cfgimpl_parent = parent
        self._cfgimpl_values: Dict[str, Any] = {}
        self._cfgimpl_warnings: List[str] = []
        self._cfgimpl_build(overrides)

    def _cfgimpl_build(self, overrides):
        for child in self._cfgimpl_descr._children:
            if isinstance(child, Option):
                self._cfgimpl_values[child._name] = child.getdefault()
                self._cfgimpl_value_owners[child._name] = 'default'
            elif isinstance(child, OptionDescription):
                self._cfgimpl_values[child._name] = Config(child, parent=self)

    def copy(self, as_default=False, parent=None):
        result = Config.__new__(self.__class__)
        result._cfgimpl_descr = self._cfgimpl_descr
        result._cfgimpl_value_owners = owners = {}
        result._cfgimpl_parent = parent
        result._cfgimpl_values = v = {}
        for child in self._cfgimpl_descr._children:
            if isinstance(child, Option):
                v[child._name] = self._cfgimpl_values[child._name]
                owners[child._name] = 'default' if as_default else self._cfgimpl_value_owners[child._name]
            elif isinstance(child, OptionDescription):
                v[child._name] = self._cfgimpl_values[child._name].copy(as_default, parent=result)
        return result

    def __setattr__(self, name, value):
        if self._cfgimpl_frozen and getattr(self, name) != value:
            raise TypeError("trying to change a frozen option object")
        if name.startswith('_cfgimpl_'):
            super().__setattr__(name, value)
        else:
            self.setoption(name, value, 'user')

    def __getattr__(self, name):
        if '.' in name:
            homeconfig, name = self._cfgimpl_get_home_by_path(name)
            return getattr(homeconfig, name)
        if name.startswith('_cfgimpl_'):
            raise AttributeError(f"{self.__class__} object has no attribute {name}")
        if name not in self._cfgimpl_values:
            raise AttributeError(f"{self.__class__} object has no attribute {name}")
        return self._cfgimpl_values[name]

    def __dir__(self):
        from_type = dir(type(self))
        from_dict = list(self.__dict__)
        extras = list(self._cfgimpl_values)
        return sorted(set(extras + from_type + from_dict))

    def __delattr__(self, name):
        if name.startswith('_cfgimpl_'):
            super().__delattr__(name)
        else:
            self._cfgimpl_value_owners[name] = 'default'
            opt = getattr(self._cfgimpl_descr, name)
            if isinstance(opt, OptionDescription):
                raise AttributeError("can't delete option subgroup")
            self._cfgimpl_values[name] = getattr(opt, 'default', None)

    def setoption(self, name, value, who):
        if name not in self._cfgimpl_values:
            raise AttributeError(f'unknown option {name}')
        child = getattr(self._cfgimpl_descr, name)
        oldowner = self._cfgimpl_value_owners[child._name]
        
        # Allow requirements to override user-set values if necessary
        if who == 'required' and oldowner == 'user':
            # Requirement takes precedence over user setting
            pass
        elif oldowner not in ("default", "suggested") and who not in ("default", "suggested"):
            if getattr(self, name) != value:
                raise ConflictConfigError(f'cannot override value to {value} for option {name}')
        
        child.setoption(self, value, who)
        self._cfgimpl_value_owners[name] = who

    def suggest(self, **kwargs):
        for name, value in kwargs.items():
            self.suggestoption(name, value)

    def suggestoption(self, name, value):
        # Only apply suggestion if the option hasn't been explicitly set by user
        current_owner = self._cfgimpl_value_owners.get(name, "default")
        if current_owner not in ("user", "required"):
            try:
                self.setoption(name, value, "suggested")
            except ConflictConfigError:
                pass

    def set(self, **kwargs):
        all_paths = [p.split(".") for p in self.getpaths()]
        for key, value in kwargs.items():
            key_p = key.split('.')
            candidates = [p for p in all_paths if p[-len(key_p):] == key_p]
            if len(candidates) == 1:
                name = '.'.join(candidates[0])
                homeconfig, name = self._cfgimpl_get_home_by_path(name)
                homeconfig.setoption(name, value, "user")
            elif len(candidates) > 1:
                raise AmbigousOptionError(f'more than one option that ends with {key}')
            else:
                raise NoMatchingOptionFound(f'there is no option that matches {key}')

    def _cfgimpl_get_home_by_path(self, path: str) -> Tuple['Config', str]:
        path = path.split('.')
        config = self
        for step in path[:-1]:
            config = getattr(config, step)
        return config, path[-1]

    def _cfgimpl_get_toplevel(self) -> 'Config':
        config = self
        while config._cfgimpl_parent is not None:
            config = config._cfgimpl_parent
        return config

    def add_warning(self, warning: str):
        self._cfgimpl_get_toplevel()._cfgimpl_warnings.append(warning)

    def get_warnings(self) -> List[str]:
        return self._cfgimpl_get_toplevel()._cfgimpl_warnings

    def _freeze_(self):
        self._cfgimpl_frozen = True
        return True

    def getkey(self):
        return self._cfgimpl_descr.getkey(self)

    def __hash__(self):
        return hash(self.getkey())

    def __eq__(self, other):
        return self.getkey() == other.getkey()

    def __ne__(self, other):
        return not self == other

    def __iter__(self):
        for child in self._cfgimpl_descr._children:
            if isinstance(child, Option):
                yield child._name, getattr(self, child._name)

    def __str__(self, indent=""):
        lines = []
        children = sorted((child._name, child) for child in self._cfgimpl_descr._children)
        for name, child in children:
            if self._cfgimpl_value_owners.get(name, 'default') == 'default':
                continue
            value = getattr(self, name)
            if isinstance(value, Config):
                substr = value.__str__(indent + "    ")
            else:
                substr = f"{indent}    {name} = {value}"
            if substr:
                lines.append(substr)
        if indent and not lines:
            return ''
        lines.insert(0, f"{indent}[{self._cfgimpl_descr._name}]")
        return '\n'.join(lines)

    def getpaths(self, include_groups=False) -> List[str]:
        return self._cfgimpl_descr.getpaths(include_groups=include_groups)

DEFAULT_OPTION_NAME = object()

class Option(metaclass=extendabletype):
    def __init__(self, name: str, doc: str, cmdline=DEFAULT_OPTION_NAME):
        self._name = name
        self.doc = doc
        self.cmdline = cmdline

    def validate(self, value) -> bool:
        raise NotImplementedError('abstract base class')

    def getdefault(self):
        return self.default

    def setoption(self, config: Config, value, who: str):
        name = self._name
        if who == "default" and value is None:
            return
        if not self.validate(value):
            raise ConfigError(f'invalid value {value} for option {name}')
        config._cfgimpl_values[name] = value

    def getkey(self, value):
        return value

    def convert_from_cmdline(self, value):
        return value

    def add_optparse_option(self, argnames, parser, config):
        callback = ConfigUpdate(config, self)
        parser.add_option(help=f"{self.doc} %default",
                          action='callback', type=self.opt_type,
                          callback=callback, metavar=self._name.upper(),
                          *argnames)

class ChoiceOption(Option):
    opt_type = 'string'

    def __init__(self, name: str, doc: str, values: list, default=None,
                 requires: Optional[dict] = None, suggests: Optional[dict] = None,
                 cmdline=DEFAULT_OPTION_NAME):
        super().__init__(name, doc, cmdline)
        self.values = values
        self.default = default
        self._requires = requires or {}
        self._suggests = suggests or {}

    def setoption(self, config: Config, value, who: str):
        for path, reqvalue in self._requires.get(value, []):
            toplevel = config._cfgimpl_get_toplevel()
            homeconfig, name = toplevel._cfgimpl_get_home_by_path(path)
            who2 = 'default' if who == 'default' else 'required'
            homeconfig.setoption(name, reqvalue, who2)
        for path, reqvalue in self._suggests.get(value, []):
            toplevel = config._cfgimpl_get_toplevel()
            homeconfig, name = toplevel._cfgimpl_get_home_by_path(path)
            homeconfig.suggestoption(name, reqvalue)
        super().setoption(config, value, who)

    def validate(self, value) -> bool:
        return value is None or value in self.values

    def convert_from_cmdline(self, value):
        return value.strip()

def _getnegation(optname: str) -> str:
    if optname.startswith("without"):
        return "with" + optname[len("without"):]
    if optname.startswith("with"):
        return "without" + optname[len("with"):]
    return "no-" + optname

class BoolOption(Option):
    def __init__(self, name: str, doc: str, default=None, requires=None,
                 suggests=None, validator=None, cmdline=DEFAULT_OPTION_NAME,
                 negation=True):
        super().__init__(name, doc, cmdline=cmdline)
        self._requires = requires
        self._suggests = suggests
        self.default = default
        self.negation = negation
        self._validator = validator

    def validate(self, value) -> bool:
        return isinstance(value, bool)

    def setoption(self, config: Config, value, who: str):
        if value and self._validator is not None:
            self._validator(config._cfgimpl_get_toplevel())
        if value and self._requires is not None:
            for path, reqvalue in self._requires:
                toplevel = config._cfgimpl_get_toplevel()
                homeconfig, name = toplevel._cfgimpl_get_home_by_path(path)
                who2 = 'default' if who == 'default' else 'required'
                homeconfig.setoption(name, reqvalue, who2)
        if value and self._suggests is not None:
            for path, reqvalue in self._suggests:
                toplevel = config._cfgimpl_get_toplevel()
                homeconfig, name = toplevel._cfgimpl_get_home_by_path(path)
                homeconfig.suggestoption(name, reqvalue)
        super().setoption(config, value, who)

    def add_optparse_option(self, argnames, parser, config):
        callback = BoolConfigUpdate(config, self, True)
        parser.add_option(help=f"{self.doc} %default",
                          action='callback', callback=callback, *argnames)
        if not self.negation:
            return
        no_argnames = ["--" + _getnegation(argname.lstrip("-")) 
                       for argname in argnames if argname.startswith("--")]
        if not no_argnames:
            no_argnames = ["--" + _getnegation(argname.lstrip("-")) for argname in argnames]
        callback = BoolConfigUpdate(config, self, False)
        parser.add_option(help=f"unset option set by {argnames[0]}",
                          action='callback', callback=callback, *no_argnames)

class IntOption(Option):
    opt_type = 'int'

    def __init__(self, name: str, doc: str, default=None, cmdline=DEFAULT_OPTION_NAME):
        super().__init__(name, doc, cmdline)
        self.default = default

    def validate(self, value) -> bool:
        try:
            int(value)
            return True
        except (TypeError, ValueError):
            return False

    def setoption(self, config: Config, value, who: str):
        try:
            super().setoption(config, int(value), who)
        except (TypeError, ValueError) as e:
            raise ConfigError(f"Invalid integer value: {e}")

class FloatOption(Option):
    opt_type = 'float'

    def __init__(self, name: str, doc: str, default=None, cmdline=DEFAULT_OPTION_NAME):
        super().__init__(name, doc, cmdline)
        self.default = default

    def validate(self, value) -> bool:
        try:
            float(value)
            return True
        except (TypeError, ValueError):
            return False

    def setoption(self, config: Config, value, who: str):
        try:
            super().setoption(config, float(value), who)
        except (TypeError, ValueError) as e:
            raise ConfigError(f"Invalid float value: {e}")

class StrOption(Option):
    opt_type = 'string'

    def __init__(self, name: str, doc: str, default=None, cmdline=DEFAULT_OPTION_NAME):
        super().__init__(name, doc, cmdline)
        self.default = default

    def validate(self, value) -> bool:
        return isinstance(value, str)

class ArbitraryOption(Option):
    def __init__(self, name: str, doc: str, default=None, defaultfactory=None):
        super().__init__(name, doc, cmdline=None)
        self.default = default
        self.defaultfactory = defaultfactory
        if defaultfactory is not None:
            assert default is None

    def validate(self, value) -> bool:
        return True

    def add_optparse_option(self, *args, **kwargs):
        return

    def getdefault(self):
        return self.defaultfactory() if self.defaultfactory else self.default

class OptionDescription(metaclass=extendabletype):
    cmdline = None

    def __init__(self, name: str, doc: str, children: list):
        self._name = name
        self.doc = doc
        self._children = children
        self._build()

    def _build(self):
        for child in self._children:
            setattr(self, child._name, child)

    def getkey(self, config: Config):
        return tuple(child.getkey(getattr(config, child._name)) for child in self._children)

    def add_optparse_option(self, argnames, parser, config):
        return

    def getpaths(self, include_groups=False, currpath=None) -> List[str]:
        if currpath is None:
            currpath = []
        paths = []
        for option in self._children:
            attr = option._name
            if attr.startswith('_cfgimpl'):
                continue
            value = getattr(self, attr)
            if isinstance(value, OptionDescription):
                if include_groups:
                    paths.append('.'.join(currpath + [attr]))
                currpath.append(attr)
                paths += value.getpaths(include_groups=include_groups, currpath=currpath)
                currpath.pop()
            else:
                paths.append('.'.join(currpath + [attr]))
        return paths

class OptHelpFormatter(optparse.TitledHelpFormatter):
    extra_useage = None

    def expand_default(self, option):
        assert self.parser
        dfls = self.parser.defaults
        defl = ""
        choices = None
        
        if option.action == 'callback' and isinstance(option.callback, ConfigUpdate):
            callback = option.callback
            defl = callback.help_default()
            if isinstance(callback.option, ChoiceOption):
                choices = callback.option.values
        else:
            val = dfls.get(option.dest)
            if val is None:
                pass
            elif isinstance(val, bool):
                if val is True and option.action == "store_true":
                    defl = "default"
            else:
                defl = f"default: {val}"

        if option.type == 'choice':
            choices = option.choices

        if choices is not None:
            choices_str = f"{option.metavar}={'|'.join(choices)}"
        else:
            choices_str = ""

        if '%default' in option.help:
            if choices_str and defl:
                sep = ", "
            else:
                sep = ""
            defl = f"[{choices_str}{sep}{defl}]" if choices_str or defl else ""
            return option.help.replace("%default", defl)
        elif choices_str:
            return f"{option.help} [{choices_str}]"
        return option.help

    def format_usage(self, usage):
        result = super().format_usage(usage)
        if self.extra_useage is not None:
            return f"{result}\n{self.extra_useage}\n\n"
        return result

class ConfigUpdate:
    def __init__(self, config: Config, option: Option):
        self.config = config
        self.option = option

    def convert_from_cmdline(self, value):
        return self.option.convert_from_cmdline(value)

    def __call__(self, option, opt_str, value, parser, *args, **kwargs):
        try:
            value = self.convert_from_cmdline(value)
            self.config.setoption(self.option._name, value, who='cmdline')
        except ConfigError as e:
            for warning in self.config.get_warnings():
                print(warning, file=sys.stderr)
            raise optparse.OptionValueError(str(e))

    def help_default(self):
        default = getattr(self.config, self.option._name)
        owner = self.config._cfgimpl_value_owners.get(self.option._name, 'default')
        if default is None:
            return '' if owner == 'default' else '???'
        return f"{owner}: {default}"

class BoolConfigUpdate(ConfigUpdate):
    def __init__(self, config: Config, option: Option, which_value: bool):
        super().__init__(config, option)
        self.which_value = which_value

    def convert_from_cmdline(self, value):
        return self.which_value

    def help_default(self):
        default = getattr(self.config, self.option._name)
        owner = self.config._cfgimpl_value_owners.get(self.option._name, 'default')
        return owner if default == self.which_value else ""

def to_optparse(config: Config, useoptions=None, parser=None,
                parserargs=None, parserkwargs=None, extra_useage=None):
    grps = {}
    def get_group(name: str, doc: str):
        steps = name.split('.')
        if len(steps) < 2:
            return parser
        grpname = steps[-2]
        if grpname not in grps:
            grps[grpname] = parser.add_option_group(doc)
        return grps[grpname]

    if parser is None:
        parserargs = parserargs or []
        parserkwargs = parserkwargs or {}
        formatter = OptHelpFormatter()
        formatter.extra_useage = extra_useage
        parser = optparse.OptionParser(formatter=formatter, *parserargs, **parserkwargs)
    
    if useoptions is None:
        useoptions = config.getpaths(include_groups=True)
    
    seen = set()
    for path in useoptions:
        if path.endswith(".*"):
            base_path = path[:-2]
            homeconf, name = config._cfgimpl_get_home_by_path(base_path)
            subconf = getattr(homeconf, name)
            useoptions.extend(f"{base_path}.{child}" for child in subconf.getpaths())
        else:
            if path in seen:
                continue
            seen.add(path)
            homeconf, name = config._cfgimpl_get_home_by_path(path)
            option = getattr(homeconf._cfgimpl_descr, name)
            if option.cmdline is DEFAULT_OPTION_NAME:
                chunks = (f"--{path.replace('.', '-')}",)
            elif option.cmdline is None:
                continue
            else:
                chunks = option.cmdline.split(' ')
            grp = get_group(path, homeconf._cfgimpl_descr.doc)
            option.add_optparse_option(chunks, grp, homeconf)
    return parser

def make_dict(config: Config) -> Dict[str, Any]:
    return {path: getattr(config, path) for path in config.getpaths()}