# Copyright (C) 2005 Canonical Ltd

# 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



"""Code to show logs of changes.

Various flavors of log can be produced:

* for one file, or the whole tree, and (not done yet) for
  files in a given directory

* in "verbose" mode with a description of what changed from one
  version to the next

* with file-ids and revision-ids shown

* from last to first or (not anymore) from first to last;
  the default is "reversed" because it shows the likely most
  relevant and interesting information first

* (not yet) in XML format
"""



def find_touching_revisions(branch, file_id):
    """Yield a description of revisions which affect the file_id.

    Each returned element is (revno, revision_id, description)

    This is the list of revisions where the file is either added,
    modified, renamed or deleted.

    TODO: Perhaps some way to limit this to only particular revisions,
    or to traverse a non-mainline set of revisions?
    """
    last_ie = None
    last_path = None
    revno = 1
    for revision_id in branch.revision_history():
        this_inv = branch.get_revision_inventory(revision_id)
        if file_id in this_inv:
            this_ie = this_inv[file_id]
            this_path = this_inv.id2path(file_id)
        else:
            this_ie = this_path = None

        # now we know how it was last time, and how it is in this revision.
        # are those two states effectively the same or not?

        if not this_ie and not last_ie:
            # not present in either
            pass
        elif this_ie and not last_ie:
            yield revno, revision_id, "added " + this_path
        elif not this_ie and last_ie:
            # deleted here
            yield revno, revision_id, "deleted " + last_path
        elif this_path != last_path:
            yield revno, revision_id, ("renamed %s => %s" % (last_path, this_path))
        elif (this_ie.text_size != last_ie.text_size
              or this_ie.text_sha1 != last_ie.text_sha1):
            yield revno, revision_id, "modified " + this_path

        last_ie = this_ie
        last_path = this_path
        revno += 1



def show_log(branch,
             specific_fileid=None,
             show_timezone='original',
             verbose=False,
             show_ids=False,
             to_file=None,
             direction='reverse'):
    """Write out human-readable log of commits to this branch.

    specific_fileid
        If true, list only the commits affecting the specified
        file, rather than all commits.

    show_timezone
        'original' (committer's timezone),
        'utc' (universal time), or
        'local' (local user's timezone)

    verbose
        If true show added/changed/deleted/renamed files.

    show_ids
        If true, show revision and file ids.

    to_file
        File to send log to; by default stdout.

    direction
        'reverse' (default) is latest to earliest;
        'forward' is earliest to latest.
    """
    from osutils import format_date
    from errors import BzrCheckError
    from diff import compare_trees
    from textui import show_status

    if to_file == None:
        import sys
        to_file = sys.stdout

    if specific_fileid or verbose:
        raise NotImplementedError('sorry, option not implemented at the moment')
    
    which_revs = branch.enum_history(direction)

    for revno, revision_id in which_revs:
        # TODO: if filename given, check if it's changed; if not
        # changed, skip this one

        # TODO: if verbose, get a list of changes; if we're running
        # forward then the delta is as compared to the previous
        # version, otherwise as compared to the *next* version to be
        # enumerated; in both cases must treat 0 specially as the
        # empty tree.

        rev = branch.get_revision(revision_id)
        delta = None
        show_one_log(revno, rev, delta, show_ids, to_file, show_timezone)


def junk():
    precursor = None
    if verbose:
        from tree import EmptyTree
        prev_tree = EmptyTree()
    for revno, revision_id in which_revs:
        precursor = revision_id

    if revision_id != rev.revision_id:
        raise BzrCheckError("retrieved wrong revision: %r"
                            % (revision_id, rev.revision_id))

    if verbose:
        this_tree = branch.revision_tree(revision_id)
        delta = compare_trees(prev_tree, this_tree, want_unchanged=False)
        prev_tree = this_tree
    else:
        delta = None    



def show_one_log(revno, rev, delta, show_ids, to_file, show_timezone):
    from osutils import format_date
    
    print >>to_file,  '-' * 60
    print >>to_file,  'revno:', revno
    if show_ids:
        print >>to_file,  'revision-id:', rev.revision_id
    print >>to_file,  'committer:', rev.committer
    print >>to_file,  'timestamp: %s' % (format_date(rev.timestamp, rev.timezone or 0,
                                         show_timezone))

    print >>to_file,  'message:'
    if not rev.message:
        print >>to_file,  '  (no message)'
    else:
        for l in rev.message.split('\n'):
            print >>to_file,  '  ' + l

    if delta != None:
        delta.show(to_file, show_ids)