import importlib
import sys
import zipfile

from ebook_converter.constants_old import numeric_version
from ebook_converter.ptempfile import PersistentTemporaryFile


class PluginNotFound(ValueError):
    pass


class InvalidPlugin(ValueError):
    pass


class Plugin(object):
    """
    A calibre plugin. Useful members include:

       * ``self.plugin_path``: Stores path to the ZIP file that contains
                               this plugin or None if it is a builtin
                               plugin
       * ``self.site_customization``: Stores a customization string entered
                                      by the user.

    Methods that should be overridden in sub classes:

       * :meth:`initialize`
       * :meth:`customization_help`

    Useful methods:

        * :meth:`temporary_file`
        * :meth:`__enter__`
        * :meth:`load_resources`

    """
    #: List of platforms this plugin works on.
    #: For example: ``['windows', 'osx', 'linux']``
    supported_platforms = []

    #: The name of this plugin. You must set it something other
    #: than Trivial Plugin for it to work.
    name = 'Trivial Plugin'

    #: The version of this plugin as a 3-tuple (major, minor, revision)
    version = (1, 0, 0)

    #: A short string describing what this plugin does
    description = 'Does absolutely nothing'

    #: The author of this plugin
    author = 'Unknown'

    #: When more than one plugin exists for a filetype,
    #: the plugins are run in order of decreasing priority.
    #: Plugins with higher priority will be run first.
    #: The highest possible priority is ``sys.maxsize``.
    #: Default priority is 1.
    priority = 1

    #: The earliest version of calibre this plugin requires
    minimum_calibre_version = (0, 4, 118)

    #: If False, the user will not be able to disable this plugin. Use with
    #: care.
    can_be_disabled = True

    #: The type of this plugin. Used for categorizing plugins in the
    #: GUI
    type = 'Base'

    def __init__(self, plugin_path):
        self.plugin_path = plugin_path
        self.site_customization = None

    def initialize(self):
        """
        Called once when calibre plugins are initialized.  Plugins are
        re-initialized every time a new plugin is added. Also note that if the
        plugin is run in a worker process, such as for adding books, then the
        plugin will be initialized for every new worker process.

        Perform any plugin specific initialization here, such as extracting
        resources from the plugin ZIP file. The path to the ZIP file is
        available as ``self.plugin_path``.

        Note that ``self.site_customization`` is **not** available at this
        point.
        """
        pass

    def config_widget(self):
        """
        Implement this method and :meth:`save_settings` in your plugin to
        use a custom configuration dialog, rather then relying on the simple
        string based default customization.

        This method, if implemented, must return a QWidget. The widget can have
        an optional method validate() that takes no arguments and is called
        immediately after the user clicks OK. Changes are applied if and only
        if the method returns True.

        If for some reason you cannot perform the configuration at this time,
        return a tuple of two strings (message, details), these will be
        displayed as a warning dialog to the user and the process will be
        aborted.
        """
        raise NotImplementedError()

    def save_settings(self, config_widget):
        """
        Save the settings specified by the user with config_widget.

        :param config_widget: The widget returned by :meth:`config_widget`.

        """
        raise NotImplementedError()

    def load_resources(self, names):
        """
        If this plugin comes in a ZIP file (user added plugin), this method
        will allow you to load resources from the ZIP file.

        For example to load an image::

            pixmap = QPixmap()
            pixmap.loadFromData(self.load_resources(['images/icon.png'])['images/icon.png'])
            icon = QIcon(pixmap)

        :param names: List of paths to resources in the ZIP file using / as
                      separator

        :return: A dictionary of the form ``{name: file_contents}``. Any names
                 that were not found in the ZIP file will not be present in the
                 dictionary.

        """
        if self.plugin_path is None:
            raise ValueError('This plugin was not loaded from a ZIP file')
        ans = {}
        with zipfile.ZipFile(self.plugin_path, 'r') as zf:
            for candidate in zf.namelist():
                if candidate in names:
                    ans[candidate] = zf.read(candidate)
        return ans

    def customization_help(self, gui=False):
        """
        Return a string giving help on how to customize this plugin.
        By default raise a :class:`NotImplementedError`, which indicates that
        the plugin does not require customization.

        If you re-implement this method in your subclass, the user will
        be asked to enter a string as customization for this plugin.
        The customization string will be available as
        ``self.site_customization``.

        Site customization could be anything, for example, the path to
        a needed binary on the user's computer.

        :param gui: If True return HTML help, otherwise return plain text help.

        """
        raise NotImplementedError()

    def temporary_file(self, suffix):
        """
        Return a file-like object that is a temporary file on the file system.
        This file will remain available even after being closed and will only
        be removed on interpreter shutdown. Use the ``name`` member of the
        returned object to access the full path to the created temporary file.

        :param suffix: The suffix that the temporary file will have.
        """
        return PersistentTemporaryFile(suffix)

    def is_customizable(self):
        try:
            self.customization_help()
            return True
        except NotImplementedError:
            return False

    def __enter__(self, *args):
        """
        Add this plugin to the python path so that it's contents become
        directly importable.  Useful when bundling large python libraries into
        the plugin. Use it like this::
            with plugin:
                import something
        """
        if self.plugin_path is not None:
            from ebook_converter.utils.zipfile import ZipFile
            zf = ZipFile(self.plugin_path)
            extensions = {x.rpartition('.')[-1].lower() for x in
                          zf.namelist()}
            zip_safe = True
            for ext in ('pyd', 'so', 'dll', 'dylib'):
                if ext in extensions:
                    zip_safe = False
                    break
            if zip_safe:
                sys.path.insert(0, self.plugin_path)
                self.sys_insertion_path = self.plugin_path
            else:
                from ebook_converter.ptempfile import TemporaryDirectory
                self._sys_insertion_tdir = TemporaryDirectory('plugin_unzip')
                self.sys_insertion_path = (self._sys_insertion_tdir.
                                           __enter__(*args))
                zf.extractall(self.sys_insertion_path)
                sys.path.insert(0, self.sys_insertion_path)
            zf.close()

    def __exit__(self, *args):
        ip = getattr(self, 'sys_insertion_path', None),
        it = getattr(self, '_sys_insertion_tdir', None)
        if ip in sys.path:
            sys.path.remove(ip)
        if hasattr(it, '__exit__'):
            it.__exit__(*args)

    def cli_main(self, args):
        """
        This method is the main entry point for your plugins command line
        interface. It is called when the user does: calibre-debug -r "Plugin
        Name". Any arguments passed are present in the args variable.
        """
        raise NotImplementedError('The %s plugin has no command line interface'
                                  % self.name)


class FileTypePlugin(Plugin):
    """
    A plugin that is associated with a particular set of file types.
    """

    #: Set of file types for which this plugin should be run.
    #: Use '*' for all file types.
    #: For example: ``{'lit', 'mobi', 'prc'}``
    file_types = set()

    #: If True, this plugin is run when books are added
    #: to the database
    on_import = False

    #: If True, this plugin is run after books are added
    #: to the database. In this case the postimport and postadd
    #: methods of the plugin are called.
    on_postimport = False

    #: If True, this plugin is run just before a conversion
    on_preprocess = False

    #: If True, this plugin is run after conversion
    #: on the final file produced by the conversion output plugin.
    on_postprocess = False

    type = 'File type'

    def run(self, path_to_ebook):
        """
        Run the plugin. Must be implemented in subclasses.
        It should perform whatever modifications are required
        on the e-book and return the absolute path to the
        modified e-book. If no modifications are needed, it should
        return the path to the original e-book. If an error is encountered
        it should raise an Exception. The default implementation
        simply return the path to the original e-book. Note that the path to
        the original file (before any file type plugins are run, is available
        as self.original_path_to_file).

        The modified e-book file should be created with the
        :meth:`temporary_file` method.

        :param path_to_ebook: Absolute path to the e-book.

        :return: Absolute path to the modified e-book.
        """
        # Default implementation does nothing
        return path_to_ebook

    def postimport(self, book_id, book_format, db):
        """
        Called post import, i.e., after the book file has been added to the
        database. Note that this is different from :meth:`postadd` which is
        called when the book record is created for the first time. This method
        is called whenever a new file is added to a book record. It is useful
        for modifying the book record based on the contents of the newly added
        file.

        :param book_id: Database id of the added book.
        :param book_format: The file type of the book that was added.
        :param db: Library database.
        """
        pass  # Default implementation does nothing

    def postadd(self, book_id, fmt_map, db):
        """
        Called post add, i.e. after a book has been added to the db. Note that
        this is different from :meth:`postimport`, which is called after a
        single book file has been added to a book. postadd() is called only
        when an entire book record with possibly more than one book file has
        been created for the first time.  This is useful if you wish to modify
        the book record in the database when the book is first added to
        calibre.

        :param book_id: Database id of the added book.
        :param fmt_map: Map of file format to path from which the file format
            was added. Note that this might or might not point to an actual
            existing file, as sometimes files are added as streams. In which
            case it might be a dummy value or a non-existent path.
        :param db: Library database
        """
        pass  # Default implementation does nothing


class MetadataReaderPlugin(Plugin):
    """
    A plugin that implements reading metadata from a set of file types.
    """
    #: Set of file types for which this plugin should be run.
    #: For example: ``set(['lit', 'mobi', 'prc'])``
    file_types = set()

    supported_platforms = ['osx', 'linux']
    version = numeric_version
    author = 'Kovid Goyal'

    type = 'Metadata reader'

    def __init__(self, *args, **kwargs):
        Plugin.__init__(self, *args, **kwargs)
        self.quick = False

    def get_metadata(self, stream, type):
        """
        Return metadata for the file represented by stream (a file like object
        that supports reading). Raise an exception when there is an error
        with the input data.

        :param type: The type of file. Guaranteed to be one of the entries
                     in :attr:`file_types`.
        :return: A :class:`ebook_converter.ebooks.metadata.book.Metadata`
                 object
        """
        return None


class MetadataWriterPlugin(Plugin):
    """
    A plugin that implements reading metadata from a set of file types.
    """
    #: Set of file types for which this plugin should be run.
    #: For example: ``set(['lit', 'mobi', 'prc'])``
    file_types = set()

    supported_platforms = ['osx', 'linux']
    version = numeric_version
    author = 'Kovid Goyal'

    type = 'Metadata writer'

    def __init__(self, *args, **kwargs):
        Plugin.__init__(self, *args, **kwargs)
        self.apply_null = False

    def set_metadata(self, stream, mi, type):
        """
        Set metadata for the file represented by stream (a file like object
        that supports reading). Raise an exception when there is an error
        with the input data.

        :param type: The type of file. Guaranteed to be one of the entries
                     in :attr:`file_types`.
        :param mi: A :class:`ebook_converter.ebooks.metadata.book.Metadata`
                   object
        """
        pass


class CatalogPlugin(Plugin):
    """
    A plugin that implements a catalog generator.
    """

    resources_path = None

    #: Output file type for which this plugin should be run.
    #: For example: 'epub' or 'xml'
    file_types = set()

    type = 'Catalog generator'

    #: CLI parser options specific to this plugin, declared as namedtuple
    #: Option:
    #:
    #:   from collections import namedtuple
    #:   Option = namedtuple('Option', 'option, default, dest, help')
    #:   cli_options = [Option('--catalog-title', default = 'My Catalog',
    #:   dest = 'catalog_title', help = ('Title of generated catalog. '
    #:                                     '\nDefault:' +
    #:                                   " '" + '%default' + "'"))]
    #:   cli_options parsed in
    #:   ebook_converter.db.cli.cmd_catalog:option_parser()
    #:
    cli_options = []

    def _field_sorter(self, key):
        """
        Custom fields sort after standard fields
        """
        if key.startswith('#'):
            return '~%s' % key[1:]
        else:
            return key

    def search_sort_db(self, db, opts):

        db.search(opts.search_text)

        if opts.sort_by:
            # 2nd arg = ascending
            db.sort(opts.sort_by, True)
        return db.get_data_as_dict(ids=opts.ids)

    def get_output_fields(self, db, opts):
        # Return a list of requested fields
        all_std_fields = {'author_sort', 'authors', 'comments', 'cover',
                          'formats', 'id', 'isbn', 'library_name', 'ondevice',
                          'pubdate', 'publisher', 'rating', 'series_index',
                          'series', 'size', 'tags', 'timestamp', 'title_sort',
                          'title', 'uuid', 'languages', 'identifiers'}
        all_custom_fields = set(db.custom_field_keys())
        for field in list(all_custom_fields):
            fm = db.field_metadata[field]
            if fm['datatype'] == 'series':
                all_custom_fields.add(field+'_index')
        all_fields = all_std_fields.union(all_custom_fields)

        if opts.fields != 'all':
            # Make a list from opts.fields
            of = [x.strip() for x in opts.fields.split(',')]
            requested_fields = set(of)

            # Validate requested_fields
            if requested_fields - all_fields:
                from ebook_converter.library import current_library_name
                invalid_fields = sorted(list(requested_fields - all_fields))
                print("invalid --fields specified: %s" %
                      ', '.join(invalid_fields))
                print("available fields in '%s': %s" %
                      (current_library_name(),
                       ', '.join(sorted(list(all_fields)))))
                raise ValueError("unable to generate catalog with specified "
                                 "fields")

            fields = [x for x in of if x in all_fields]
        else:
            fields = sorted(all_fields, key=self._field_sorter)

        if (not opts.connected_device['is_device_connected'] and
                'ondevice' in fields):
            fields.pop(int(fields.index('ondevice')))

        return fields

    def initialize(self):
        """
        If plugin is not a built-in, copy the plugin's .ui and .py files from
        the ZIP file to $TMPDIR.
        Tab will be dynamically generated and added to the Catalog Options
        dialog in ebook_converter.gui2.dialogs.catalog.py:Catalog
        """

        # TODO(gryf): remove this entire abomination in favor of map and lazy
        # importing if needed.
        from ebook_converter.customize.builtins import plugins as \
            builtin_plugins
        if not type(self) in builtin_plugins:
            raise ValueError(f'Plugin type "{self.__str__}" not found')

    def run(self, path_to_output, opts, db, ids, notification=None):
        """
        Run the plugin. Must be implemented in subclasses.
        It should generate the catalog in the format specified
        in file_types, returning the absolute path to the
        generated catalog file. If an error is encountered
        it should raise an Exception.

        The generated catalog file should be created with the
        :meth:`temporary_file` method.

        :param path_to_output: Absolute path to the generated catalog file.
        :param opts: A dictionary of keyword arguments
        :param db: A LibraryDatabase2 object
        """
        # Default implementation does nothing
        raise NotImplementedError('CatalogPlugin.generate_catalog() default '
                                  'method, should be overridden in subclass')


class InterfaceActionBase(Plugin):

    supported_platforms = ['osx', 'linux']
    author = 'Kovid Goyal'
    type = 'User interface action'
    can_be_disabled = False

    actual_plugin = None

    def __init__(self, *args, **kwargs):
        Plugin.__init__(self, *args, **kwargs)
        self.actual_plugin_ = None

    def load_actual_plugin(self, gui):
        """
        This method must return the actual interface action plugin object.
        """
        ac = self.actual_plugin_
        if ac is None:
            mod, cls = self.actual_plugin.split(':')
            ac = getattr(importlib.import_module(mod),
                         cls)(gui, self.site_customization)
            self.actual_plugin_ = ac
        return ac


class PreferencesPlugin(Plugin):

    """
    A plugin representing a widget displayed in the Preferences dialog.

    This plugin has only one important method :meth:`create_widget`. The
    various fields of the plugin control how it is categorized in the UI.
    """

    supported_platforms = ['osx', 'linux']
    author = 'Kovid Goyal'
    type = 'Preferences'
    can_be_disabled = False

    #: Import path to module that contains a class named ConfigWidget
    #: which implements the ConfigWidgetInterface. Used by
    #: :meth:`create_widget`.
    config_widget = None

    #: Where in the list of categories the :attr:`category` of this plugin
    #: should be.
    category_order = 100

    #: Where in the list of names in a category, the :attr:`gui_name` of this
    #: plugin should be
    name_order = 100

    #: The category this plugin should be in
    category = None

    #: The category name displayed to the user for this plugin
    gui_category = None

    #: The name displayed to the user for this plugin
    gui_name = None

    #: The icon for this plugin, should be an absolute path
    icon = None

    #: The description used for tooltips and the like
    description = None

    def create_widget(self, parent=None):
        """
        Create and return the actual Qt widget used for setting this group of
        preferences. The widget must implement the
        :class:`ebook_converter.gui2.preferences.ConfigWidgetInterface`.

        The default implementation uses :attr:`config_widget` to instantiate
        the widget.
        """
        base, _, wc = self.config_widget.partition(':')
        if not wc:
            wc = 'ConfigWidget'
        base = importlib.import_module(base)
        widget = getattr(base, wc)
        return widget(parent)


class StoreBase(Plugin):

    supported_platforms = ['osx', 'linux']
    author = 'John Schember'
    type = 'Store'
    # Information about the store. Should be in the primary language
    # of the store. This should not be translatable when set by
    # a subclass.
    description = 'An e-book store.'
    minimum_calibre_version = (0, 8, 0)
    version = (1, 0, 1)

    actual_plugin = None

    # Does the store only distribute e-books without DRM.
    drm_free_only = False
    # This is the 2 letter country code for the corporate
    # headquarters of the store.
    headquarters = ''
    # All formats the store distributes e-books in.
    formats = []
    # Is this store on an affiliate program?
    affiliate = False

    def load_actual_plugin(self, gui):
        """
        This method must return the actual interface action plugin object.
        """
        mod, cls = self.actual_plugin.split(':')
        self.actual_plugin_object = getattr(importlib.import_module(mod),
                                            cls)(gui, self.name)
        return self.actual_plugin_object

    def customization_help(self, gui=False):
        if getattr(self, 'actual_plugin_object', None) is not None:
            return self.actual_plugin_object.customization_help(gui)
        raise NotImplementedError()

    def config_widget(self):
        if getattr(self, 'actual_plugin_object', None) is not None:
            return self.actual_plugin_object.config_widget()
        raise NotImplementedError()

    def save_settings(self, config_widget):
        if getattr(self, 'actual_plugin_object', None) is not None:
            return self.actual_plugin_object.save_settings(config_widget)
        raise NotImplementedError()


class EditBookToolPlugin(Plugin):

    type = 'Edit book tool'
    minimum_calibre_version = (1, 46, 0)


class LibraryClosedPlugin(Plugin):
    """
    LibraryClosedPlugins are run when a library is closed, either at shutdown,
    when the library is changed, or when a library is used in some other way.
    At the moment these plugins won't be called by the CLI functions.
    """
    type = 'Library closed'

    # minimum version 2.54 because that is when support was added
    minimum_calibre_version = (2, 54, 0)

    def run(self, db):
        """
        The db will be a reference to the new_api (db.cache.py).

        The plugin must run to completion. It must not use the GUI, threads, or
        any signals.
        """
        raise NotImplementedError('LibraryClosedPlugin '
                                  'run method must be overridden in subclass')
