from mercurial import util as merc_util
from mercurial import hg
from svn import core

import util
import hg_delta_editor
import svnwrap
import fetch_command
import utility_commands


@util.register_subcommand('push')
@util.register_subcommand('dcommit') # for git expats
def push_revisions_to_subversion(ui, repo, hg_repo_path, svn_url, **opts):
    """Push revisions starting at a specified head back to Subversion.
    """
    oldencoding = merc_util._encoding
    merc_util._encoding = 'UTF-8'
    hge = hg_delta_editor.HgChangeReceiver(hg_repo_path,
                                           ui_=ui)
    svn_commit_hashes = dict(zip(hge.revmap.itervalues(),
                                 hge.revmap.iterkeys()))
    # Strategy:
    # 1. Find all outgoing commits from this head
    outgoing = utility_commands.outgoing_revisions(ui, repo, hge,
                                                   svn_commit_hashes)
    if not (outgoing and len(outgoing)):
        ui.status('No revisions to push.')
        return 0
    if len(repo.parents()) != 1:
        ui.status('Cowardly refusing to push branch merge')
        return 1
    while outgoing:
        oldest = outgoing.pop(-1)
        old_ctx = repo[oldest]
        if len(old_ctx.parents()) != 1:
            ui.status('Found a branch merge, this needs discussion and '
                      'implementation.')
            return 1
        base_n = old_ctx.parents()[0].node()
        old_children = repo[base_n].children()
        # 2. Commit oldest revision that needs to be pushed
        base_revision = svn_commit_hashes[old_ctx.parents()[0].node()][0]
        commit_from_rev(ui, repo, old_ctx, hge, svn_url, base_revision)
        # 3. Fetch revisions from svn
        r = fetch_command.fetch_revisions(ui, svn_url, hg_repo_path)
        assert not r or r == 0
        # 4. Find the new head of the target branch
        repo = hg.repository(ui, hge.path)
        base_c = repo[base_n]
        replacement = [c for c in base_c.children() if c not in old_children
                       and c.branch() == old_ctx.branch()]
        assert len(replacement) == 1
        replacement = replacement[0]
        # 5. Rebase all children of the currently-pushing rev to the new branch
        heads = repo.heads(old_ctx.node())
        for needs_transplant in heads:
            hg.clean(repo, needs_transplant)
            utility_commands.rebase_commits(ui, repo, hg_repo_path, **opts)
            repo = hg.repository(ui, hge.path)
            if needs_transplant in outgoing:
                hg.clean(repo, repo['tip'].node())
                hge = hg_delta_editor.HgChangeReceiver(hg_repo_path, ui_=ui)
                svn_commit_hashes = dict(zip(hge.revmap.itervalues(),
                                             hge.revmap.iterkeys()))
                outgoing = utility_commands.outgoing_revisions(ui, repo, hge,
                                                              svn_commit_hashes)
    merc_util._encoding = oldencoding
    return 0


def _findmissing(dirname, svn, branch_path):
    """Find missing directories in svn. dirname *must* end in a /
    """
    assert dirname[-1] == '/'
    missing = []
    keep_checking = True
    # check and see if the dir exists svn-side.
    path = dirname
    while keep_checking:
        try:
            assert svn.list_dir('%s/%s' % (branch_path, path))
            keep_checking = False
        except core.SubversionException, e:
            # dir must not exist
            missing.append(path[:-1])
            path = '/'.join(path.split('/')[:-2] + [''])
    return missing

def commit_from_rev(ui, repo, rev_ctx, hg_editor, svn_url, base_revision):
    """Build and send a commit from Mercurial to Subversion.
    """
    file_data = {}
    svn = svnwrap.SubversionRepo(svn_url, username=merc_util.getuser())
    parent = rev_ctx.parents()[0]
    parent_branch = rev_ctx.parents()[0].branch()
    branch_path = 'trunk'

    if parent_branch and parent_branch != 'default':
        branch_path = 'branches/%s' % parent_branch

    added_dirs = []
    props = {}
    copies = {}
    for file in rev_ctx.files():
        new_data = base_data = ''
        action = ''
        if file in rev_ctx:
            fctx = rev_ctx.filectx(file)
            new_data = fctx.data()

            if 'x' in fctx.flags():
                props.setdefault(file, {})['svn:executable'] = '*'
            if 'l' in fctx.flags():
                props.setdefault(file, {})['svn:special'] = '*'

            if file not in parent:
                renamed = fctx.renamed()
                if renamed:
                    # TODO current model (and perhaps svn model) does not support
                    # this kind of renames: a -> b, b -> c
                    copies[file] = renamed[0]
                    base_data = parent[renamed[0]].data()

                action = 'add'
                dirname = '/'.join(file.split('/')[:-1] + [''])
                # check for new directories
                if not list(parent.walk(util.PrefixMatch(dirname))):
                    added_dirs += _findmissing(dirname, svn, branch_path)
            else:
                base_data = parent.filectx(file).data()
                if ('x' in parent.filectx(file).flags()
                    and 'x' not in rev_ctx.filectx(file).flags()):
                    props.setdefault(file, {})['svn:executable'] = None
                if ('l' in parent.filectx(file).flags()
                    and 'l' not in rev_ctx.filectx(file).flags()):
                    props.setdefault(file, {})['svn:special'] = None
                action = 'modify'
        else:
            base_data = parent.filectx(file).data()
            action = 'delete'
        file_data[file] = base_data, new_data, action

    # TODO check for directory deletes here
    def svnpath(p):
        return '%s/%s' % (branch_path, p)

    newcopies = {}
    for source, dest in copies.iteritems():
        newcopies[svnpath(source)] = (svnpath(dest), base_revision)

    new_target_files = [svnpath(f) for f in rev_ctx.files()]
    for tf, ntf in zip(rev_ctx.files(), new_target_files):
        if tf in file_data:
            file_data[ntf] = file_data[tf]
            if tf in props:
                props[ntf] = props[tf]
                del props[tf]
            if merc_util.binary(file_data[ntf][1]):
                props.setdefault(ntf, {}).update(props.get(ntf, {}))
                props.setdefault(ntf, {})['svn:mime-type'] = 'application/octet-stream'
            del file_data[tf]
    added_dirs = ['%s/%s' % (branch_path, f) for f in added_dirs]
    added_dirs = set(added_dirs)
    new_target_files += added_dirs
    try:
        svn.commit(new_target_files, rev_ctx.description(), file_data,
                   base_revision, set(added_dirs), props, newcopies)
    except core.SubversionException, e:
        if hasattr(e, 'apr_err') and e.apr_err == 160028:
            raise merc_util.Abort('Base text was out of date, maybe rebase?')
        else:
            raise