# -*- coding: utf-8 -*-
"""Package to deal with saving and retrieving user specific settings."""
import os
from datetime import datetime
from abc import ABC, abstractmethod
import configparser
import json
from typing import Any
from functools import lru_cache
from pathlib import Path

import appdirs
import keyring

from ..version import __version__


class ASettingRegistry(ABC):
    """Abstract class defining structure of **SettingRegistry** class.

    It is implementing methods to store secure items into keyring, otherwise
    mechanism for storing common items must be implemented in abstract
    methods.

    Attributes:
        _name (str): Registry names.

    """

    def __init__(self, name: str):
        super(ASettingRegistry, self).__init__()
        self._name = name
        self._items = {}

    def set_item(self, name: str, value: str) -> None:
        """Set item to settings registry.

        Args:
            name (str): Name of the item.
            value (str): Value of the item.

        """
        self._set_item(name, value)

    @abstractmethod
    def _set_item(self, name: str, value: str) -> None:
        # Implement it
        pass

    def __setitem__(self, name, value):
        self._items[name] = value
        self._set_item(name, value)

    def get_item(self, name: str) -> str:
        """Get item from settings registry.

        Args:
            name (str): Name of the item.

        Returns:
            value (str): Value of the item.

        Raises:
            ValueError: If item doesn't exist.

        """
        return self._get_item(name)

    @abstractmethod
    def _get_item(self, name: str) -> str:
        # Implement it
        pass

    def __getitem__(self, name):
        return self._get_item(name)

    def delete_item(self, name: str):
        """Delete item from settings registry.

        Args:
            name (str): Name of the item.

        Returns:
            value (str): Value of the item.

        """
        self._delete_item(name)

    @abstractmethod
    def _delete_item(self, name: str):
        """Delete item from settings.

        Note:
            see :meth:`pype.lib.user_settings.ARegistrySettings.delete_item`

        """
        pass

    def __delitem__(self, name):
        del self._items[name]
        self._delete_item(name)

    def set_secure_item(self, name: str, value: str) -> None:
        """Set sensitive item into system's keyring.

        This uses `Keyring module`_ to save sensitive stuff into system's
        keyring.

        Args:
            name (str): Name of the item.
            value (str): Value of the item.

        .. _Keyring module:
            https://github.com/jaraco/keyring

        """
        keyring.set_password(self._name, name, value)

    @lru_cache(maxsize=32)
    def get_secure_item(self, name: str) -> str:
        """Get value of sensitive item from system's keyring.

        See also `Keyring module`_

        Args:
            name (str): Name of the item.

        Returns:
            value (str): Value of the item.

        Raises:
            ValueError: If item doesn't exist.

        .. _Keyring module:
            https://github.com/jaraco/keyring

        """
        value = keyring.get_password(self._name, name)
        if not value:
            raise ValueError(
                f"Item {self._name}:{name} does not exist in keyring.")
        return value

    def delete_secure_item(self, name: str) -> None:
        """Delete value stored in system's keyring.

        See also `Keyring module`_

        Args:
            name (str): Name of the item to be deleted.

        .. _Keyring module:
            https://github.com/jaraco/keyring

        """
        self.get_secure_item.cache_clear()
        keyring.delete_password(self._name, name)


class IniSettingRegistry(ASettingRegistry):
    """Class using :mod:`configparser`.

    This class is using :mod:`configparser` (ini) files to store items.

    """

    def __init__(self, name, path: str):
        super(IniSettingRegistry, self).__init__(name)
        # get registry file
        self._registry_file = os.path.join(path, f"{name}.ini")
        if not os.path.exists(self._registry_file):
            with open(self._registry_file, mode="w") as cfg:
                print("# Settings registry", cfg)
                print(f"# Generated by Pype {__version__}", cfg)
                now = datetime.now().strftime("%d/%m/%Y %H:%M:%S")
                print(f"# {now} ")

    def set_item_section(
            self, section: str, name: str, value: str) -> None:
        """Set item to specific section of ini registry.

        If section doesn't exists, it is created.

        Args:
            section (str): Name of section.
            name (str): Name of the item.
            value (str): Value of the item.

        """
        value = str(value)
        config = configparser.ConfigParser()

        config.read(self._registry_file)
        if not config.has_section(section):
            config.add_section(section)
        current = config[section]
        current[name] = value

        with open(self._registry_file, mode="w") as cfg:
            config.write(cfg)

    def _set_item(self, name: str, value: str) -> None:

        self.set_item_section("MAIN", name, value)

    def set_item(self, name: str, value: str) -> None:
        """Set item to settings ini file.

        This saves item to ``DEFAULT`` section of ini as each item there
        must reside in some section.

        Args:
            name (str): Name of the item.
            value (str): Value of the item.

        """
        # this does the some, overridden just for different docstring.
        # we cast value to str as ini options values must be strings.
        super(IniSettingRegistry, self).set_item(name, str(value))

    def get_item(self, name: str) -> str:
        """Gets item from settings ini file.

        This gets settings from ``DEFAULT`` section of ini file as each item
        there must reside in some section.

        Args:
            name (str): Name of the item.

        Returns:
            str: Value of item.

        Raises:
            ValueError: If value doesn't exist.

        """
        return super(IniSettingRegistry, self).get_item(name)

    @lru_cache(maxsize=32)
    def get_item_from_section(self, section: str, name: str) -> str:
        """Get item from section of ini file.

        This will read ini file and try to get item value from specified
        section. If that section or item doesn't exist, :exc:`ValueError`
        is risen.

        Args:
            section (str): Name of ini section.
            name (str): Name of the item.

        Returns:
            str: Item value.

        Raises:
            ValueError: If value doesn't exist.

        """
        config = configparser.ConfigParser()
        config.read(self._registry_file)
        try:
            value = config[section][name]
        except KeyError:
            raise ValueError(
                f"Registry doesn't contain value {section}:{name}")
        return value

    def _get_item(self, name: str) -> str:
        return self.get_item_from_section("MAIN", name)

    def delete_item_from_section(self, section: str, name: str) -> None:
        """Delete item from section in ini file.

        Args:
            section (str): Section name.
            name (str): Name of the item.

        Raises:
            ValueError: If item doesn't exist.

        """
        self.get_item_from_section.cache_clear()
        config = configparser.ConfigParser()
        config.read(self._registry_file)
        try:
            _ = config[section][name]
        except KeyError:
            raise ValueError(
                f"Registry doesn't contain value {section}:{name}")
        config.remove_option(section, name)

        # if section is empty, delete it
        if len(config[section].keys()) == 0:
            config.remove_section(section)

        with open(self._registry_file, mode="w") as cfg:
            config.write(cfg)

    def _delete_item(self, name):
        """Delete item from default section.

        Note:
            See :meth:`~pype.lib.IniSettingsRegistry.delete_item_from_section`

        """
        self.delete_item_from_section("MAIN", name)


class JSONSettingRegistry(ASettingRegistry):
    """Class using json file as storage."""

    def __init__(self, name, path: str):
        super(JSONSettingRegistry, self).__init__(name)
        #: str: name of registry file
        self._registry_file = Path(os.path.join(path, f"{name}.json"))
        now = datetime.now().strftime("%d/%m/%Y %H:%M:%S")
        header = {
            "__metadata__": {
                "pype-version": __version__,
                "generated": now
            },
            "registry": {}
        }

        self._registry_file.parent.mkdir(parents=True)
        if not os.path.exists(self._registry_file):
            with open(self._registry_file, mode="w") as cfg:
                json.dump(header, cfg, indent=4)

    @lru_cache(maxsize=32)
    def _get_item(self, name: str) -> Any:
        """Get item value from registry json.

        Note:
            See :meth:`pype.lib.JSONSettingRegistry.get_item`

        """
        with open(self._registry_file, mode="r") as cfg:
            data = json.load(cfg)
            try:
                value = data["registry"][name]
            except KeyError:
                raise ValueError(
                    f"Registry doesn't contain value {name}")
        return value

    def get_item(self, name: str) -> Any:
        """Get item value from registry json.

        Args:
            name (str): Name of the item.

        Returns:
            value of the item

        Raises:
            ValueError: If item is not found in registry file.

        """
        return self._get_item(name)

    def _set_item(self, name: str, value: Any) -> None:
        """Set item value to registry json.

        Note:
            See :meth:`pype.lib.JSONSettingRegistry.set_item`

        """
        with open(self._registry_file, "r+") as cfg:
            data = json.load(cfg)
            data["registry"][name] = value
            cfg.truncate(0)
            cfg.seek(0)
            json.dump(data, cfg, indent=4)

    def set_item(self, name: str, value: Any) -> None:
        """Set item and its value into json registry file.

        Args:
            name (str): name of the item.
            value (Any): value of the item.

        """
        self._set_item(name, value)

    def _delete_item(self, name: str):
        self._get_item.cache_clear()
        with open(self._registry_file, "r+") as cfg:
            data = json.load(cfg)
            del data["registry"][name]
            cfg.truncate(0)
            cfg.seek(0)
            json.dump(data, cfg, indent=4)


class PypeSettingsRegistry(JSONSettingRegistry):
    """Class handling Pype general settings registry.

    Attributes:
        vendor (str): Name used for path construction.
        product (str): Additional name used for path construction.

    """
    vendor = "pypeclub"
    product = "pype"

    def __init__(self):
        path = appdirs.user_data_dir(self.product, self.vendor)
        super(PypeSettingsRegistry, self).__init__("pype_settings", path)