import os

from mercurial import hg
from mercurial import node
from mercurial import patch
from mercurial import util as hgutil

from svn import core
from svn import delta

import hg_delta_editor
import svnwrap
import stupid as stupidmod
import cmdutil
import util
import utility_commands


def pull(ui, svn_url, hg_repo_path, skipto_rev=0, stupid=None,
         tag_locations='tags', authors=None, filemap=None, **opts):
    """pull new revisions from Subversion
    """
    svn_url = util.normalize_url(svn_url)
    old_encoding = util.swap_out_encoding()
    skipto_rev=int(skipto_rev)
    have_replay = not stupid
    if have_replay and not callable(
        delta.svn_txdelta_apply(None, None, None)[0]): #pragma: no cover
        ui.status('You are using old Subversion SWIG bindings. Replay will not'
                  ' work until you upgrade to 1.5.0 or newer. Falling back to'
                  ' a slower method that may be buggier. Please upgrade, or'
                  ' contribute a patch to use the ctypes bindings instead'
                  ' of SWIG.\n')
        have_replay = False
    initializing_repo = False
    user = opts.get('username', hgutil.getuser())
    passwd = opts.get('password', '')
    svn = svnwrap.SubversionRepo(svn_url, user, passwd)
    author_host = "@%s" % svn.uuid
    tag_locations = tag_locations.split(',')
    hg_editor = hg_delta_editor.HgChangeReceiver(hg_repo_path,
                                                 ui_=ui,
                                                 subdir=svn.subdir,
                                                 author_host=author_host,
                                                 tag_locations=tag_locations,
                                                 authors=authors,
                                                 filemap=filemap)
    if os.path.exists(hg_editor.uuid_file):
        uuid = open(hg_editor.uuid_file).read()
        assert uuid == svn.uuid
        start = hg_editor.last_known_revision()
    else:
        open(hg_editor.uuid_file, 'w').write(svn.uuid)
        open(hg_editor.svn_url_file, 'w').write(svn_url)
        initializing_repo = True
        start = skipto_rev

    if initializing_repo and start > 0:
        raise hgutil.Abort('Revision skipping at repository initialization '
                           'remains unimplemented.')

    # start converting revisions
    for r in svn.revisions(start=start):
        valid = True
        hg_editor.update_branch_tag_map_for_rev(r)
        for p in r.paths:
            if hg_editor._is_path_valid(p):
                valid = True
                break
        if valid:
            # got a 502? Try more than once!
            tries = 0
            converted = False
            while not converted:
                try:
                    util.describe_revision(ui, r)
                    if have_replay:
                        try:
                            cmdutil.replay_convert_rev(hg_editor, svn, r)
                        except svnwrap.SubversionRepoCanNotReplay, e: #pragma: no cover
                            ui.status('%s\n' % e.message)
                            stupidmod.print_your_svn_is_old_message(ui)
                            have_replay = False
                            stupidmod.svn_server_pull_rev(ui, svn, hg_editor, r)
                    else:
                        stupidmod.svn_server_pull_rev(ui, svn, hg_editor, r)
                    converted = True
                except core.SubversionException, e: #pragma: no cover
                    if (e.apr_err == core.SVN_ERR_RA_DAV_REQUEST_FAILED
                        and '502' in str(e)
                        and tries < 3):
                        tries += 1
                        ui.status('Got a 502, retrying (%s)\n' % tries)
                    else:
                        raise hgutil.Abort(*e.args)
    util.swap_out_encoding(old_encoding)

pull = util.register_subcommand('pull')(pull)


def push(ui, repo, hg_repo_path, svn_url, stupid=False, **opts):
    """push revisions starting at a specified head back to Subversion.
    """
    old_encoding = util.swap_out_encoding()
    hge = hg_delta_editor.HgChangeReceiver(hg_repo_path,
                                           ui_=ui)
    svn_commit_hashes = dict(zip(hge.revmap.itervalues(),
                                 hge.revmap.iterkeys()))
    user = opts.get('username', hgutil.getuser())
    passwd = opts.get('password', '')

    # Strategy:
    # 1. Find all outgoing commits from this head
    if len(repo.parents()) != 1:
        ui.status('Cowardly refusing to push branch merge')
        return 1
    workingrev = repo.parents()[0]
    outgoing = util.outgoing_revisions(ui, repo, hge, svn_commit_hashes, workingrev.node())
    if not (outgoing and len(outgoing)):
        ui.status('No revisions to push.')
        return 0
    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()
        svnbranch = repo[base_n].branch()
        oldtip = base_n
        samebranchchildren = [c for c in repo[oldtip].children() if c.branch() == svnbranch
                              and c.node() in svn_commit_hashes]
        while samebranchchildren:
            oldtip = samebranchchildren[0].node()
            samebranchchildren = [c for c in repo[oldtip].children() if c.branch() == svnbranch
                                  and c.node() in svn_commit_hashes]
        # 2. Commit oldest revision that needs to be pushed
        base_revision = svn_commit_hashes[base_n][0]
        try:
            cmdutil.commit_from_rev(ui, repo, old_ctx, hge, svn_url,
                                    base_revision, user, passwd)
        except cmdutil.NoFilesException:
            ui.warn("Could not push revision %s because it had no changes in svn.\n" %
                     old_ctx)
            return 1
        # 3. Fetch revisions from svn
        r = pull(ui, svn_url, hg_repo_path, stupid=stupid,
                 username=user, password=passwd)
        assert not r or r == 0
        # 4. Find the new head of the target branch
        repo = hg.repository(ui, hge.path)
        oldtipctx = repo[oldtip]
        replacement = [c for c in oldtipctx.children() if c not in old_children
                       and c.branch() == oldtipctx.branch()]
        assert len(replacement) == 1, 'Replacement node came back as: %r' % replacement
        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:
            def extrafn(ctx, extra):
                if ctx.node() == oldest:
                    return
                extra['branch'] = ctx.branch()
            utility_commands.rebase_commits(ui, repo,
                                            extrafn=extrafn,
                                            sourcerev=needs_transplant,
                                            **opts)
            repo = hg.repository(ui, hge.path)
            for child in repo[replacement.node()].children():
                rebasesrc = node.bin(child.extra().get('rebase_source', node.hex(node.nullid)))
                if rebasesrc in outgoing:
                    while rebasesrc in outgoing:
                        rebsrcindex = outgoing.index(rebasesrc)
                        outgoing = (outgoing[0:rebsrcindex] +
                                    [child.node(), ] + outgoing[rebsrcindex+1:])
                        children = [c for c in child.children() if c.branch() == child.branch()]
                        if children:
                            child = children[0]
                        rebasesrc = node.bin(child.extra().get('rebase_source', node.hex(node.nullid)))
        hge = hg_delta_editor.HgChangeReceiver(hg_repo_path, ui_=ui)
        svn_commit_hashes = dict(zip(hge.revmap.itervalues(), hge.revmap.iterkeys()))
    util.swap_out_encoding(old_encoding)
    return 0
push = util.register_subcommand('push')(push)
# for git expats
dcommit = util.register_subcommand('dcommit')(push)


def diff(ui, repo, hg_repo_path, **opts):
    """show a diff of the most recent revision against its parent from svn
    """
    hge = hg_delta_editor.HgChangeReceiver(hg_repo_path,
                                           ui_=ui)
    svn_commit_hashes = dict(zip(hge.revmap.itervalues(),
                                 hge.revmap.iterkeys()))
    parent = repo.parents()[0]
    o_r = util.outgoing_revisions(ui, repo, hge, svn_commit_hashes, parent.node())
    if o_r:
        parent = repo[o_r[-1]].parents()[0]
    base_rev, _junk = svn_commit_hashes[parent.node()]
    it = patch.diff(repo, parent.node(), None,
                    opts=patch.diffopts(ui, opts={'git': True,
                                                  'show_function': False,
                                                  'ignore_all_space': False,
                                                  'ignore_space_change': False,
                                                  'ignore_blank_lines': False,
                                                  'unified': True,
                                                  'text': False,
                                                  }))
    ui.write(cmdutil.filterdiff(''.join(it), base_rev))
diff = util.register_subcommand('diff')(diff)