# -*- coding: utf-8 -*-
"""
    vcs.nodes
    ~~~~~~~~~

    Module holding everything related to vcs nodes.

    :created_on: Apr 8, 2010
    :copyright: (c) 2010-2011 by Marcin Kuzminski, Lukasz Balcerzak.
"""

import functools
import mimetypes
import posixpath
import stat

from kallithea.lib.vcs.backends.base import EmptyChangeset
from kallithea.lib.vcs.exceptions import NodeError, RemovedFileNodeError
from kallithea.lib.vcs.utils import safe_bytes, safe_str
from kallithea.lib.vcs.utils.lazy import LazyProperty


class NodeKind:
    SUBMODULE = -1
    DIR = 1
    FILE = 2


class NodeState:
    ADDED = 'added'
    CHANGED = 'changed'
    NOT_CHANGED = 'not changed'
    REMOVED = 'removed'


class NodeGeneratorBase(object):
    """
    Base class for removed added and changed filenodes, it's a lazy generator
    class that will create filenodes only on iteration or call

    The len method doesn't need to create filenodes at all
    """

    def __init__(self, current_paths, cs):
        self.cs = cs
        self.current_paths = current_paths

    def __getitem__(self, key):
        assert isinstance(key, slice), key
        for p in self.current_paths[key]:
            yield self.cs.get_node(p)

    def __len__(self):
        return len(self.current_paths)

    def __iter__(self):
        for p in self.current_paths:
            yield self.cs.get_node(p)


class AddedFileNodesGenerator(NodeGeneratorBase):
    """
    Class holding Added files for current changeset
    """
    pass


class ChangedFileNodesGenerator(NodeGeneratorBase):
    """
    Class holding Changed files for current changeset
    """
    pass


class RemovedFileNodesGenerator(NodeGeneratorBase):
    """
    Class holding removed files for current changeset
    """
    def __iter__(self):
        for p in self.current_paths:
            yield RemovedFileNode(path=p)

    def __getitem__(self, key):
        assert isinstance(key, slice), key
        for p in self.current_paths[key]:
            yield RemovedFileNode(path=p)


@functools.total_ordering
class Node(object):
    """
    Simplest class representing file or directory on repository.  SCM backends
    should use ``FileNode`` and ``DirNode`` subclasses rather than ``Node``
    directly.

    Node's ``path`` cannot start with slash as we operate on *relative* paths
    only. Moreover, every single node is identified by the ``path`` attribute,
    so it cannot end with slash, too. Otherwise, path could lead to mistakes.
    """

    def __init__(self, path, kind):
        if path.startswith('/'):
            raise NodeError("Cannot initialize Node objects with slash at "
                            "the beginning as only relative paths are supported")
        self.path = path.rstrip('/')
        if path == '' and kind != NodeKind.DIR:
            raise NodeError("Only DirNode and its subclasses may be "
                            "initialized with empty path")
        self.kind = kind
        #self.dirs, self.files = [], []
        if self.is_root() and not self.is_dir():
            raise NodeError("Root node cannot be FILE kind")

    @LazyProperty
    def parent(self):
        parent_path = self.get_parent_path()
        if parent_path:
            if self.changeset:
                return self.changeset.get_node(parent_path)
            return DirNode(parent_path)
        return None

    @LazyProperty
    def name(self):
        """
        Returns name of the node so if its path
        then only last part is returned.
        """
        return self.path.rstrip('/').split('/')[-1]

    def __eq__(self, other):
        if type(self) is not type(other):
            return False
        if self.kind != other.kind:
            return False
        if self.path != other.path:
            return False

    def __lt__(self, other):
        if self.kind < other.kind:
            return True
        if self.kind > other.kind:
            return False
        if self.path < other.path:
            return True
        if self.path > other.path:
            return False

    def __repr__(self):
        return '<%s %r>' % (self.__class__.__name__, self.path)

    def get_parent_path(self):
        """
        Returns node's parent path or empty string if node is root.
        """
        if self.is_root():
            return ''
        return posixpath.dirname(self.path.rstrip('/')) + '/'

    def is_file(self):
        """
        Returns ``True`` if node's kind is ``NodeKind.FILE``, ``False``
        otherwise.
        """
        return self.kind == NodeKind.FILE

    def is_dir(self):
        """
        Returns ``True`` if node's kind is ``NodeKind.DIR``, ``False``
        otherwise.
        """
        return self.kind == NodeKind.DIR

    def is_root(self):
        """
        Returns ``True`` if node is a root node and ``False`` otherwise.
        """
        return self.kind == NodeKind.DIR and self.path == ''

    def is_submodule(self):
        """
        Returns ``True`` if node's kind is ``NodeKind.SUBMODULE``, ``False``
        otherwise.
        """
        return self.kind == NodeKind.SUBMODULE

    @LazyProperty
    def added(self):
        return self.state is NodeState.ADDED

    @LazyProperty
    def changed(self):
        return self.state is NodeState.CHANGED

    @LazyProperty
    def not_changed(self):
        return self.state is NodeState.NOT_CHANGED

    @LazyProperty
    def removed(self):
        return self.state is NodeState.REMOVED


class FileNode(Node):
    """
    Class representing file nodes.

    :attribute: path: path to the node, relative to repository's root
    :attribute: content: if given arbitrary sets content of the file
    :attribute: changeset: if given, first time content is accessed, callback
    :attribute: mode: octal stat mode for a node. Default is 0100644.
    """

    def __init__(self, path, content=None, changeset=None, mode=None):
        """
        Only one of ``content`` and ``changeset`` may be given. Passing both
        would raise ``NodeError`` exception.

        :param path: relative path to the node
        :param content: content may be passed to constructor
        :param changeset: if given, will use it to lazily fetch content
        :param mode: octal representation of ST_MODE (i.e. 0100644)
        """

        if content and changeset:
            raise NodeError("Cannot use both content and changeset")
        super(FileNode, self).__init__(path, kind=NodeKind.FILE)
        self.changeset = changeset
        if not isinstance(content, bytes) and content is not None:
            # File content is one thing that inherently must be bytes ... but
            # VCS module tries to be "user friendly" and support unicode ...
            content = safe_bytes(content)
        self._content = content
        self._mode = mode or 0o100644

    def __eq__(self, other):
        eq = super(FileNode, self).__eq__(other)
        if eq is not None:
            return eq
        return self.content == other.content

    def __lt__(self, other):
        lt = super(FileNode, self).__lt__(other)
        if lt is not None:
            return lt
        return self.content < other.content

    @LazyProperty
    def mode(self):
        """
        Returns lazily mode of the FileNode. If ``changeset`` is not set, would
        use value given at initialization or 0100644 (default).
        """
        if self.changeset:
            mode = self.changeset.get_file_mode(self.path)
        else:
            mode = self._mode
        return mode

    @property
    def content(self):
        """
        Returns lazily byte content of the FileNode.
        """
        if self.changeset:
            content = self.changeset.get_file_content(self.path)
        else:
            content = self._content
        return content

    @LazyProperty
    def size(self):
        if self.changeset:
            return self.changeset.get_file_size(self.path)
        raise NodeError("Cannot retrieve size of the file without related "
            "changeset attribute")

    @LazyProperty
    def message(self):
        if self.changeset:
            return self.last_changeset.message
        raise NodeError("Cannot retrieve message of the file without related "
            "changeset attribute")

    @LazyProperty
    def last_changeset(self):
        if self.changeset:
            return self.changeset.get_file_changeset(self.path)
        raise NodeError("Cannot retrieve last changeset of the file without "
            "related changeset attribute")

    def get_mimetype(self):
        """
        Mimetype is calculated based on the file's content.
        """

        mtype, encoding = mimetypes.guess_type(self.name)

        if mtype is None:
            if self.is_binary:
                mtype = 'application/octet-stream'
                encoding = None
            else:
                mtype = 'text/plain'
                encoding = None

                # try with pygments
                from pygments import lexers
                try:
                    mt = lexers.get_lexer_for_filename(self.name).mimetypes
                except lexers.ClassNotFound:
                    mt = None

                if mt:
                    mtype = mt[0]

        return mtype, encoding

    @LazyProperty
    def mimetype(self):
        """
        Wrapper around full mimetype info. It returns only type of fetched
        mimetype without the encoding part. use get_mimetype function to fetch
        full set of (type,encoding)
        """
        return self.get_mimetype()[0]

    @LazyProperty
    def mimetype_main(self):
        return self.mimetype.split('/')[0]

    @LazyProperty
    def lexer(self):
        """
        Returns pygment's lexer class. Would try to guess lexer taking file's
        content, name and mimetype.
        """
        from pygments import lexers
        try:
            lexer = lexers.guess_lexer_for_filename(self.name, safe_str(self.content), stripnl=False)
        except lexers.ClassNotFound:
            lexer = lexers.TextLexer(stripnl=False)
        # returns first alias
        return lexer

    @LazyProperty
    def lexer_alias(self):
        """
        Returns first alias of the lexer guessed for this file.
        """
        return self.lexer.aliases[0]

    @LazyProperty
    def history(self):
        """
        Returns a list of changeset for this file in which the file was changed
        """
        if self.changeset is None:
            raise NodeError('Unable to get changeset for this FileNode')
        return self.changeset.get_file_history(self.path)

    @LazyProperty
    def annotate(self):
        """
        Returns a list of three element tuples with lineno,changeset and line
        """
        if self.changeset is None:
            raise NodeError('Unable to get changeset for this FileNode')
        return self.changeset.get_file_annotate(self.path)

    @LazyProperty
    def state(self):
        if not self.changeset:
            raise NodeError("Cannot check state of the node if it's not "
                "linked with changeset")
        elif self.path in (node.path for node in self.changeset.added):
            return NodeState.ADDED
        elif self.path in (node.path for node in self.changeset.changed):
            return NodeState.CHANGED
        else:
            return NodeState.NOT_CHANGED

    @property
    def is_binary(self):
        """
        Returns True if file has binary content.
        """
        return b'\0' in self.content

    def is_browser_compatible_image(self):
        return self.mimetype in [
            "image/gif",
            "image/jpeg",
            "image/png",
            "image/bmp"
        ]

    @LazyProperty
    def extension(self):
        """Returns filenode extension"""
        return self.name.split('.')[-1]

    @property
    def is_executable(self):
        """
        Returns ``True`` if file has executable flag turned on.
        """
        return bool(self.mode & stat.S_IXUSR)

    def __repr__(self):
        return '<%s %r @ %s>' % (self.__class__.__name__, self.path,
                                 getattr(self.changeset, 'short_id', ''))


class RemovedFileNode(FileNode):
    """
    Dummy FileNode class - trying to access any public attribute except path,
    name, kind or state (or methods/attributes checking those two) would raise
    RemovedFileNodeError.
    """
    ALLOWED_ATTRIBUTES = [
        'name', 'path', 'state', 'is_root', 'is_file', 'is_dir', 'kind',
        'added', 'changed', 'not_changed', 'removed'
    ]

    def __init__(self, path):
        """
        :param path: relative path to the node
        """
        super(RemovedFileNode, self).__init__(path=path)

    def __getattribute__(self, attr):
        if attr.startswith('_') or attr in RemovedFileNode.ALLOWED_ATTRIBUTES:
            return super(RemovedFileNode, self).__getattribute__(attr)
        raise RemovedFileNodeError("Cannot access attribute %s on "
            "RemovedFileNode" % attr)

    @LazyProperty
    def state(self):
        return NodeState.REMOVED


class DirNode(Node):
    """
    DirNode stores list of files and directories within this node.
    Nodes may be used standalone but within repository context they
    lazily fetch data within same repository's changeset.
    """

    def __init__(self, path, nodes=(), changeset=None):
        """
        Only one of ``nodes`` and ``changeset`` may be given. Passing both
        would raise ``NodeError`` exception.

        :param path: relative path to the node
        :param nodes: content may be passed to constructor
        :param changeset: if given, will use it to lazily fetch content
        :param size: always 0 for ``DirNode``
        """
        if nodes and changeset:
            raise NodeError("Cannot use both nodes and changeset")
        super(DirNode, self).__init__(path, NodeKind.DIR)
        self.changeset = changeset
        self._nodes = nodes

    def __eq__(self, other):
        eq = super(DirNode, self).__eq__(other)
        if eq is not None:
            return eq
        # check without entering each dir
        self_nodes_paths = list(sorted(n.path for n in self.nodes))
        other_nodes_paths = list(sorted(n.path for n in self.nodes))
        return self_nodes_paths == other_nodes_paths

    def __lt__(self, other):
        lt = super(DirNode, self).__lt__(other)
        if lt is not None:
            return lt
        # check without entering each dir
        self_nodes_paths = list(sorted(n.path for n in self.nodes))
        other_nodes_paths = list(sorted(n.path for n in self.nodes))
        return self_nodes_paths < other_nodes_paths

    @LazyProperty
    def nodes(self):
        if self.changeset:
            nodes = self.changeset.get_nodes(self.path)
        else:
            nodes = self._nodes
        self._nodes_dict = dict((node.path, node) for node in nodes)
        return sorted(nodes)

    @LazyProperty
    def files(self):
        return sorted((node for node in self.nodes if node.is_file()))

    @LazyProperty
    def dirs(self):
        return sorted((node for node in self.nodes if node.is_dir()))

    def __iter__(self):
        for node in self.nodes:
            yield node

    def get_node(self, path):
        """
        Returns node from within this particular ``DirNode``, so it is now
        allowed to fetch, i.e. node located at 'docs/api/index.rst' from node
        'docs'. In order to access deeper nodes one must fetch nodes between
        them first - this would work::

           docs = root.get_node('docs')
           docs.get_node('api').get_node('index.rst')

        :param: path - relative to the current node

        .. note::
           To access lazily (as in example above) node have to be initialized
           with related changeset object - without it node is out of
           context and may know nothing about anything else than nearest
           (located at same level) nodes.
        """
        try:
            path = path.rstrip('/')
            if path == '':
                raise NodeError("Cannot retrieve node without path")
            self.nodes  # access nodes first in order to set _nodes_dict
            paths = path.split('/')
            if len(paths) == 1:
                if not self.is_root():
                    path = '/'.join((self.path, paths[0]))
                else:
                    path = paths[0]
                return self._nodes_dict[path]
            elif len(paths) > 1:
                if self.changeset is None:
                    raise NodeError("Cannot access deeper "
                                    "nodes without changeset")
                else:
                    path1, path2 = paths[0], '/'.join(paths[1:])
                    return self.get_node(path1).get_node(path2)
            else:
                raise KeyError
        except KeyError:
            raise NodeError("Node does not exist at %s" % path)

    @LazyProperty
    def state(self):
        raise NodeError("Cannot access state of DirNode")

    @LazyProperty
    def size(self):
        size = 0
        for root, dirs, files in self.changeset.walk(self.path):
            for f in files:
                size += f.size

        return size

    def __repr__(self):
        return '<%s %r @ %s>' % (self.__class__.__name__, self.path,
                                 getattr(self.changeset, 'short_id', ''))


class RootNode(DirNode):
    """
    DirNode being the root node of the repository.
    """

    def __init__(self, nodes=(), changeset=None):
        super(RootNode, self).__init__(path='', nodes=nodes,
            changeset=changeset)

    def __repr__(self):
        return '<%s>' % self.__class__.__name__


class SubModuleNode(Node):
    """
    represents a SubModule of Git or SubRepo of Mercurial
    """
    is_binary = False
    size = 0

    def __init__(self, name, url, changeset=None, alias=None):
        # Note: Doesn't call Node.__init__!
        self.path = name.rstrip('/')
        self.kind = NodeKind.SUBMODULE
        self.alias = alias
        # we have to use emptyChangeset here since this can point to svn/git/hg
        # submodules we cannot get from repository
        self.changeset = EmptyChangeset(changeset, alias=alias)
        self.url = url

    def __repr__(self):
        return '<%s %r @ %s>' % (self.__class__.__name__, self.path,
                                 getattr(self.changeset, 'short_id', ''))

    @LazyProperty
    def name(self):
        """
        Returns name of the node so if its path
        then only last part is returned.
        """
        org = self.path.rstrip('/').rsplit('/', 1)[-1]
        return '%s @ %s' % (org, self.changeset.short_id)
