#! /usr/bin/env python
# -*- coding: UTF-8 -*-

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""Inventories map files to their name in a revision."""


__copyright__ = "Copyright (C) 2005 Canonical Ltd."
__author__ = "Martin Pool <mbp@canonical.com>"

import sys, os.path, types
from sets import Set

from xml import XMLMixin
from ElementTree import ElementTree, Element
from errors import bailout
from osutils import uuid, quotefn, splitpath, joinpath, appendpath
from trace import mutter

class InventoryEntry(XMLMixin):
    """Description of a versioned file.

    An InventoryEntry has the following fields, which are also
    present in the XML inventory-entry element:

    * *file_id*
    * *name*: (only the basename within the directory, must not
      contain slashes)
    * *kind*: "directory" or "file"
    * *directory_id*: (if absent/null means the branch root directory)
    * *text_sha1*: only for files
    * *text_size*: in bytes, only for files 
    * *text_id*: identifier for the text version, only for files

    InventoryEntries can also exist inside a WorkingTree
    inventory, in which case they are not yet bound to a
    particular revision of the file.  In that case the text_sha1,
    text_size and text_id are absent.


    >>> i = Inventory()
    >>> i.path2id('')
    >>> i.add(InventoryEntry('123', 'src', kind='directory'))
    >>> i.add(InventoryEntry('2323', 'hello.c', parent_id='123'))
    >>> for j in i.iter_entries():
    ...   print j
    ... 
    ('src', InventoryEntry('123', 'src', kind='directory', parent_id=None))
    ('src/hello.c', InventoryEntry('2323', 'hello.c', kind='file', parent_id='123'))
    >>> i.add(InventoryEntry('2323', 'bye.c', parent_id='123'))
    Traceback (most recent call last):
    ...
    BzrError: ('inventory already contains entry with id {2323}', [])
    >>> i.add(InventoryEntry('2324', 'bye.c', parent_id='123'))
    >>> i.add(InventoryEntry('2325', 'wibble', parent_id='123', kind='directory'))
    >>> i.path2id('src/wibble')
    '2325'
    >>> '2325' in i
    True
    >>> i.add(InventoryEntry('2326', 'wibble.c', parent_id='2325'))
    >>> i['2326']
    InventoryEntry('2326', 'wibble.c', kind='file', parent_id='2325')
    >>> for j in i.iter_entries():
    ...     print j[0]
    ...     assert i.path2id(j[0])
    ... 
    src
    src/bye.c
    src/hello.c
    src/wibble
    src/wibble/wibble.c
    >>> i.id2path('2326')
    'src/wibble/wibble.c'

    :todo: Maybe also keep the full path of the entry, and the children?
           But those depend on its position within a particular inventory, and
           it would be nice not to need to hold the backpointer here.
    """
    def __init__(self, file_id, name, kind='file', text_id=None,
                 parent_id=None):
        """Create an InventoryEntry
        
        The filename must be a single component, relative to the
        parent directory; it cannot be a whole path or relative name.

        >>> e = InventoryEntry('123', 'hello.c')
        >>> e.name
        'hello.c'
        >>> e.file_id
        '123'
        >>> e = InventoryEntry('123', 'src/hello.c')
        Traceback (most recent call last):
        BzrError: ("InventoryEntry name is not a simple filename: 'src/hello.c'", [])
        """
        
        if len(splitpath(name)) != 1:
            bailout('InventoryEntry name is not a simple filename: %r'
                    % name)
        
        self.file_id = file_id
        self.name = name
        assert kind in ['file', 'directory']
        self.kind = kind
        self.text_id = text_id
        self.parent_id = parent_id
        self.text_sha1 = None
        self.text_size = None


    def copy(self):
        other = InventoryEntry(self.file_id, self.name, self.kind,
                               self.text_id, self.parent_id)
        other.text_sha1 = self.text_sha1
        other.text_size = self.text_size
        return other


    def __repr__(self):
        return ("%s(%r, %r, kind=%r, parent_id=%r)"
                % (self.__class__.__name__,
                   self.file_id,
                   self.name,
                   self.kind,
                   self.parent_id))

    
    def to_element(self):
        """Convert to XML element"""
        e = Element('entry')

        e.set('name', self.name)
        e.set('file_id', self.file_id)
        e.set('kind', self.kind)

        if self.text_size is not None:
            e.set('text_size', '%d' % self.text_size)
            
        for f in ['text_id', 'text_sha1', 'parent_id']:
            v = getattr(self, f)
            if v is not None:
                e.set(f, v)

        e.tail = '\n'
            
        return e


    def from_element(cls, elt):
        assert elt.tag == 'entry'
        self = cls(elt.get('file_id'), elt.get('name'), elt.get('kind'))
        self.text_id = elt.get('text_id')
        self.text_sha1 = elt.get('text_sha1')
        self.parent_id = elt.get('parent_id')
        
        ## mutter("read inventoryentry: %r" % (elt.attrib))

        v = elt.get('text_size')
        self.text_size = v and int(v)

        return self
            

    from_element = classmethod(from_element)

    def __cmp__(self, other):
        if self is other:
            return 0
        if not isinstance(other, InventoryEntry):
            return NotImplemented

        return cmp(self.file_id, other.file_id) \
               or cmp(self.name, other.name) \
               or cmp(self.text_sha1, other.text_sha1) \
               or cmp(self.text_size, other.text_size) \
               or cmp(self.text_id, other.text_id) \
               or cmp(self.parent_id, other.parent_id) \
               or cmp(self.kind, other.kind)



class Inventory(XMLMixin):
    """Inventory of versioned files in a tree.

    An Inventory acts like a set of InventoryEntry items.  You can
    also look files up by their file_id or name.
    
    May be read from and written to a metadata file in a tree.  To
    manipulate the inventory (for example to add a file), it is read
    in, modified, and then written back out.

    The inventory represents a typical unix file tree, with
    directories containing files and subdirectories.  We never store
    the full path to a file, because renaming a directory implicitly
    moves all of its contents.  This class internally maintains a
    lookup tree that allows the children under a directory to be
    returned quickly.

    InventoryEntry objects must not be modified after they are
    inserted.

    >>> inv = Inventory()
    >>> inv.write_xml(sys.stdout)
    <inventory>
    </inventory>
    >>> inv.add(InventoryEntry('123-123', 'hello.c'))
    >>> inv['123-123'].name
    'hello.c'
    >>> for file_id in inv: print file_id
    ...
    123-123

    May be treated as an iterator or set to look up file ids:
    
    >>> bool(inv.path2id('hello.c'))
    True
    >>> '123-123' in inv
    True

    May also look up by name:

    >>> [x[0] for x in inv.iter_entries()]
    ['hello.c']
    
    >>> inv.write_xml(sys.stdout)
    <inventory>
    <entry file_id="123-123" kind="file" name="hello.c" />
    </inventory>

    """

    ## TODO: Clear up handling of files in subdirectories; we probably
    ## do want to be able to just look them up by name but this
    ## probably means gradually walking down the path, looking up as we go.

    ## TODO: Make sure only canonical filenames are stored.

    ## TODO: Do something sensible about the possible collisions on
    ## case-losing filesystems.  Perhaps we should just always forbid
    ## such collisions.

    ## _tree should probably just be stored as
    ## InventoryEntry._children on each directory.

    def __init__(self):
        """Create or read an inventory.

        If a working directory is specified, the inventory is read
        from there.  If the file is specified, read from that. If not,
        the inventory is created empty.
        """
        self._byid = dict()

        # _tree is indexed by parent_id; at each level a map from name
        # to ie.  The None entry is the root.
        self._tree = {None: {}}


    def __iter__(self):
        return iter(self._byid)


    def __len__(self):
        """Returns number of entries."""
        return len(self._byid)


    def iter_entries(self, parent_id=None):
        """Return (path, entry) pairs, in order by name."""
        kids = self._tree[parent_id].items()
        kids.sort()
        for name, ie in kids:
            yield name, ie
            if ie.kind == 'directory':
                for cn, cie in self.iter_entries(parent_id=ie.file_id):
                    yield joinpath([name, cn]), cie


    def directories(self, include_root=True):
        """Return (path, entry) pairs for all directories.
        """
        if include_root:
            yield '', None
        for path, entry in self.iter_entries():
            if entry.kind == 'directory':
                yield path, entry
        


    def children(self, parent_id):
        """Return entries that are direct children of parent_id."""
        return self._tree[parent_id]
                    


    # TODO: return all paths and entries


    def __contains__(self, file_id):
        """True if this entry contains a file with given id.

        >>> inv = Inventory()
        >>> inv.add(InventoryEntry('123', 'foo.c'))
        >>> '123' in inv
        True
        >>> '456' in inv
        False
        """
        return file_id in self._byid


    def __getitem__(self, file_id):
        """Return the entry for given file_id.

        >>> inv = Inventory()
        >>> inv.add(InventoryEntry('123123', 'hello.c'))
        >>> inv['123123'].name
        'hello.c'
        """
        return self._byid[file_id]


    def add(self, entry):
        """Add entry to inventory.

        To add  a file to a branch ready to be committed, use Branch.add,
        which calls this."""
        if entry.file_id in self:
            bailout("inventory already contains entry with id {%s}" % entry.file_id)

        if entry.parent_id != None:
            if entry.parent_id not in self:
                bailout("parent_id %s of new entry not found in inventory"
                        % entry.parent_id)
            
        if self._tree[entry.parent_id].has_key(entry.name):
            bailout("%s is already versioned"
                    % appendpath(self.id2path(entry.parent_id), entry.name))

        self._byid[entry.file_id] = entry
        self._tree[entry.parent_id][entry.name] = entry

        if entry.kind == 'directory':
            self._tree[entry.file_id] = {}


    def __delitem__(self, file_id):
        """Remove entry by id.

        >>> inv = Inventory()
        >>> inv.add(InventoryEntry('123', 'foo.c'))
        >>> '123' in inv
        True
        >>> del inv['123']
        >>> '123' in inv
        False
        """
        ie = self[file_id]

        assert self._tree[ie.parent_id][ie.name] == ie
        
        # TODO: Test deleting all children; maybe hoist to a separate
        # deltree method?
        if ie.kind == 'directory':
            for cie in self._tree[file_id].values():
                del self[cie.file_id]
            del self._tree[file_id]

        del self._byid[file_id]
        del self._tree[ie.parent_id][ie.name]


    def id_set(self):
        return Set(self._byid)


    def to_element(self):
        """Convert to XML Element"""
        e = Element('inventory')
        e.text = '\n'
        for path, ie in self.iter_entries():
            e.append(ie.to_element())
        return e
    

    def from_element(cls, elt):
        """Construct from XML Element

        >>> inv = Inventory()
        >>> inv.add(InventoryEntry('foo.c-123981239', 'foo.c'))
        >>> elt = inv.to_element()
        >>> inv2 = Inventory.from_element(elt)
        >>> inv2 == inv
        True
        """
        assert elt.tag == 'inventory'
        o = cls()
        for e in elt:
            o.add(InventoryEntry.from_element(e))
        return o
        
    from_element = classmethod(from_element)


    def __cmp__(self, other):
        """Compare two sets by comparing their contents.

        >>> i1 = Inventory()
        >>> i2 = Inventory()
        >>> i1 == i2
        True
        >>> i1.add(InventoryEntry('123', 'foo'))
        >>> i1 == i2
        False
        >>> i2.add(InventoryEntry('123', 'foo'))
        >>> i1 == i2
        True
        """
        if self is other:
            return 0
        
        if not isinstance(other, Inventory):
            return NotImplemented

        if self.id_set() ^ other.id_set():
            return 1

        for file_id in self._byid:
            c = cmp(self[file_id], other[file_id])
            if c: return c

        return 0


    def id2path(self, file_id):
        """Return as a list the path to file_id."""
        p = []
        while file_id != None:
            ie = self[file_id]
            p = [ie.name] + p
            file_id = ie.parent_id
        return joinpath(p)
            


    def path2id(self, name):
        """Walk down through directories to return entry of last component.

        names may be either a list of path components, or a single
        string, in which case it is automatically split.

        This returns the entry of the last component in the path,
        which may be either a file or a directory.
        """
        assert isinstance(name, types.StringTypes)

        parent_id = None
        for f in splitpath(name):
            try:
                cie = self._tree[parent_id][f]
                assert cie.name == f
                parent_id = cie.file_id
            except KeyError:
                # or raise an error?
                return None

        return parent_id


    def get_child(self, parent_id, child_name):
        return self._tree[parent_id].get(child_name)


    def has_filename(self, names):
        return bool(self.path2id(names))


    def has_id(self, file_id):
        assert isinstance(file_id, str)
        return self._byid.has_key(file_id)



if __name__ == '__main__':
    import doctest, inventory
    doctest.testmod(inventory)