#! /usr/bin/env python

"""# ____________________________________________________________
#
#            usage:  atomicmoves.py  <command-file>
# ____________________________________________________________
#
# This is an example of a command-file.  It is basically a sequence of
# 'cp' and 'rm' commands, which are atomically committed in a single new
# revision.  Unlike the 'svn' client, it allows 'rm' to be followed by
# a 'cp' that immediately replaces the entry with a new one.

# Specify the root -- which must be a svn:// or svn+ssh:// url -- and
# its expected head revision.
root   svn+ssh://snake/home/arigo/SvnRootTest/my/tmp   86

# Paste a subdir of the trunk to branch
rm dir                             branch/nbd/md5sum
cp dir     hacks/nbd/md5sum        branch/nbd/md5sum

# Restore the previous version of a file
rm file                            hacks/quantum.py
cp file    hacks/quantum.py@85     hacks/quantum.py

"""

import sys, posixpath, os
import pysvn.ra, pysvn.delta


def main(f):
    def error(msg, *args):
        raise ValueError("line %d: %s" % (linenum, msg % args))

    def cmdargs(input, cmd, nbargs):
        assert input[0] == cmd
        if len(input) != nbargs+1:
            error("%r requires exactly %d argument%s",
                  cmd, nbargs, "s"[:nbargs>1])
        return input[1:]

    lines = []
    roots = []
    linenum = 0
    for line in f:
        linenum += 1
        line = line.strip()
        if line.startswith('#'):
            continue
        input = line.split()
        if not input:
            continue
        if input[0] == 'root':
            root, rootrev = cmdargs(input, 'root', 2)
            if rootrev != 'HEAD':
                rootrev = int(rootrev)
            roots.append((root, rootrev))
            continue
        elif input[0] == 'rm':
            kind, fn2 = cmdargs(input, 'rm', 2)
            fn1 = None
        elif input[0] == 'cp':
            kind, fn1, fn2 = cmdargs(input, 'cp', 3)
        else:
            error("unknown command %r", input[0])
        if kind not in ('file', 'dir'):
            error("kind must be file or dir")
        if (fn1 and fn1.startswith('/')) or fn2.startswith('/'):
            error("absolute path not allowed")
        if '@' in fn2:
            error("cannot specify revision here")
        lines.append((kind, fn1, fn2))

    if not roots:
        raise EOFError("no 'root' specified")
    root, rootrev = roots[0]
    if roots != [(root, rootrev)]*len(roots):
        raise ValueError("multiple 'root' not allowed")
    if not lines:
        a = raw_input("Nothing to do!  Are you sure you want to continue? ")
        if not a.upper().startswith('Y'):
            raise EOFError("nothing to do")

    if rootrev == 'HEAD':
        repo = pysvn.ra.connect(root)
        rootrev = repo.get_latest_rev()
    else:
        repo = None

    deltas = []
    SEP = '-- this line, and those below, ignored --'
    loglines = ['', SEP, '']
    for kind, fn1, fn2 in lines:
        if fn1 is None:
            # remove
            d = pysvn.delta.Delta(fn2, kind, rootrev, None)
            loglines.append('D  %s' % fn2)
        else:
            # copyfrom
            if '@' in fn1:
                fn1, rev1 = fn1.split('@')
                rev1 = int(rev1)
            else:
                rev1 = rootrev
            d = pysvn.delta.Delta(fn2, kind, None, 'HEAD')
            d.copyfrom = (posixpath.join(root, fn1), rev1)
            loglines.append('A  %s (from %s, r%d)' % ((fn2,)+d.copyfrom))
        deltas.append(d)
    loglines.append('')

    logfn = 'atomicmoves-commit.tmp'
    n = 1
    while os.path.exists(logfn):
        n += 1
        logfn = 'atomicmoves-commit-%d.tmp' % n
    f = open(logfn, 'w')
    f.write('\n'.join(loglines))
    f.close()

    editor = os.environ.get('SVN_EDITOR')
    if not editor:
        editor = os.environ.get('EDITOR', 'vi')

    os.system('%s %s' % (editor, logfn))

    loglines = []
    f = open(logfn, 'r')
    for line in f:
        if line.strip() == SEP:
            break
        loglines.append(line)
    f.close()
    os.unlink(logfn)
    log = ''.join(loglines)
    if not log.strip():
        raise ValueError("no check-in message")

    if repo is None:
        repo = pysvn.ra.connect(root)
    newrev, date = repo.commit(log, deltas, {'': rootrev})
    print '%s: committed revision %d.' % (sys.argv[0], newrev)


if __name__ == '__main__':
    if len(sys.argv) != 2:
        print >> sys.stderr, __doc__
        sys.exit(2)
    main(open(sys.argv[1], 'r'))