#! /usr/bin/env python

"""Mirror a remote ftp subtree into a local directory tree.

usage: ftpmirror [-v] [-q] [-i] [-m] [-n] [-r] [-s pat]
                 [-l username [-p passwd [-a account]]]
                 hostname[:port] [remotedir [localdir]]
-v: verbose
-q: quiet
-i: interactive mode
-m: macintosh server (NCSA telnet 2.4) (implies -n -s '*.o')
-n: don't log in
-r: remove local files/directories no longer pertinent
-l username [-p passwd [-a account]]: login info (default .netrc or anonymous)
-s pat: skip files matching pattern
hostname: remote host w/ optional port separated by ':'
remotedir: remote directory (default initial)
localdir: local directory (default current)
"""

import os
import sys
import time
import getopt
import ftplib
import netrc
from fnmatch import fnmatch

# Print usage message and exit
def usage(*args):
    sys.stdout = sys.stderr
    for msg in args: print msg
    print __doc__
    sys.exit(2)

verbose = 1 # 0 for -q, 2 for -v
interactive = 0
mac = 0
rmok = 0
nologin = 0
skippats = ['.', '..', '.mirrorinfo']

# Main program: parse command line and start processing
def main():
    global verbose, interactive, mac, rmok, nologin
    try:
        opts, args = getopt.getopt(sys.argv[1:], 'a:bil:mnp:qrs:v')
    except getopt.error, msg:
        usage(msg)
    login = ''
    passwd = ''
    account = ''
    if not args: usage('hostname missing')
    host = args[0]
    port = 0
    if ':' in host:
        host, port = host.split(':', 1)
        port = int(port)
    try:
        auth = netrc.netrc().authenticators(host)
        if auth is not None:
            login, account, passwd = auth
    except (netrc.NetrcParseError, IOError):
        pass
    for o, a in opts:
        if o == '-l': login = a
        if o == '-p': passwd = a
        if o == '-a': account = a
        if o == '-v': verbose = verbose + 1
        if o == '-q': verbose = 0
        if o == '-i': interactive = 1
        if o == '-m': mac = 1; nologin = 1; skippats.append('*.o')
        if o == '-n': nologin = 1
        if o == '-r': rmok = 1
        if o == '-s': skippats.append(a)
    remotedir = ''
    localdir = ''
    if args[1:]:
        remotedir = args[1]
        if args[2:]:
            localdir = args[2]
            if args[3:]: usage('too many arguments')
    #
    f = ftplib.FTP()
    if verbose: print "Connecting to '%s%s'..." % (host,
                                                   (port and ":%d"%port or ""))
    f.connect(host,port)
    if not nologin:
        if verbose:
            print 'Logging in as %s...' % `login or 'anonymous'`
        f.login(login, passwd, account)
    if verbose: print 'OK.'
    pwd = f.pwd()
    if verbose > 1: print 'PWD =', `pwd`
    if remotedir:
        if verbose > 1: print 'cwd(%s)' % `remotedir`
        f.cwd(remotedir)
        if verbose > 1: print 'OK.'
        pwd = f.pwd()
        if verbose > 1: print 'PWD =', `pwd`
    #
    mirrorsubdir(f, localdir)

# Core logic: mirror one subdirectory (recursively)
def mirrorsubdir(f, localdir):
    pwd = f.pwd()
    if localdir and not os.path.isdir(localdir):
        if verbose: print 'Creating local directory', `localdir`
        try:
            makedir(localdir)
        except os.error, msg:
            print "Failed to establish local directory", `localdir`
            return
    infofilename = os.path.join(localdir, '.mirrorinfo')
    try:
        text = open(infofilename, 'r').read()
    except IOError, msg:
        text = '{}'
    try:
        info = eval(text)
    except (SyntaxError, NameError):
        print 'Bad mirror info in %s' % `infofilename`
        info = {}
    subdirs = []
    listing = []
    if verbose: print 'Listing remote directory %s...' % `pwd`
    f.retrlines('LIST', listing.append)
    filesfound = []
    for line in listing:
        if verbose > 1: print '-->', `line`
        if mac:
            # Mac listing has just filenames;
            # trailing / means subdirectory
            filename = line.strip()
            mode = '-'
            if filename[-1:] == '/':
                filename = filename[:-1]
                mode = 'd'
            infostuff = ''
        else:
            # Parse, assuming a UNIX listing
            words = line.split(None, 8)
            if len(words) < 6:
                if verbose > 1: print 'Skipping short line'
                continue
            filename = words[-1].lstrip()
            i = filename.find(" -> ")
            if i >= 0:
                # words[0] had better start with 'l'...
                if verbose > 1:
                    print 'Found symbolic link %s' % `filename`
                linkto = filename[i+4:]
                filename = filename[:i]
            infostuff = words[-5:-1]
            mode = words[0]
        skip = 0
        for pat in skippats:
            if fnmatch(filename, pat):
                if verbose > 1:
                    print 'Skip pattern', `pat`,
                    print 'matches', `filename`
                skip = 1
                break
        if skip:
            continue
        if mode[0] == 'd':
            if verbose > 1:
                print 'Remembering subdirectory', `filename`
            subdirs.append(filename)
            continue
        filesfound.append(filename)
        if info.has_key(filename) and info[filename] == infostuff:
            if verbose > 1:
                print 'Already have this version of',`filename`
            continue
        fullname = os.path.join(localdir, filename)
        tempname = os.path.join(localdir, '@'+filename)
        if interactive:
            doit = askabout('file', filename, pwd)
            if not doit:
                if not info.has_key(filename):
                    info[filename] = 'Not retrieved'
                continue
        try:
            os.unlink(tempname)
        except os.error:
            pass
        if mode[0] == 'l':
            if verbose:
                print "Creating symlink %s -> %s" % (
                        `filename`, `linkto`)
            try:
                os.symlink(linkto, tempname)
            except IOError, msg:
                print "Can't create %s: %s" % (
                        `tempname`, str(msg))
                continue
        else:
            try:
                fp = open(tempname, 'wb')
            except IOError, msg:
                print "Can't create %s: %s" % (
                        `tempname`, str(msg))
                continue
            if verbose:
                print 'Retrieving %s from %s as %s...' % \
                          (`filename`, `pwd`, `fullname`)
            if verbose:
                fp1 = LoggingFile(fp, 1024, sys.stdout)
            else:
                fp1 = fp
            t0 = time.time()
            try:
                f.retrbinary('RETR ' + filename,
                             fp1.write, 8*1024)
            except ftplib.error_perm, msg:
                print msg
            t1 = time.time()
            bytes = fp.tell()
            fp.close()
            if fp1 != fp:
                fp1.close()
        try:
            os.unlink(fullname)
        except os.error:
            pass            # Ignore the error
        try:
            os.rename(tempname, fullname)
        except os.error, msg:
            print "Can't rename %s to %s: %s" % (`tempname`,
                                                 `fullname`,
                                                 str(msg))
            continue
        info[filename] = infostuff
        writedict(info, infofilename)
        if verbose and mode[0] != 'l':
            dt = t1 - t0
            kbytes = bytes / 1024.0
            print int(round(kbytes)),
            print 'Kbytes in',
            print int(round(dt)),
            print 'seconds',
            if t1 > t0:
                print '(~%d Kbytes/sec)' % \
                          int(round(kbytes/dt),)
            print
    #
    # Remove files from info that are no longer remote
    deletions = 0
    for filename in info.keys():
        if filename not in filesfound:
            if verbose:
                print "Removing obsolete info entry for",
                print `filename`, "in", `localdir or "."`
            del info[filename]
            deletions = deletions + 1
    if deletions:
        writedict(info, infofilename)
    #
    # Remove local files that are no longer in the remote directory
    try:
        if not localdir: names = os.listdir(os.curdir)
        else: names = os.listdir(localdir)
    except os.error:
        names = []
    for name in names:
        if name[0] == '.' or info.has_key(name) or name in subdirs:
            continue
        skip = 0
        for pat in skippats:
            if fnmatch(name, pat):
                if verbose > 1:
                    print 'Skip pattern', `pat`,
                    print 'matches', `name`
                skip = 1
                break
        if skip:
            continue
        fullname = os.path.join(localdir, name)
        if not rmok:
            if verbose:
                print 'Local file', `fullname`,
                print 'is no longer pertinent'
            continue
        if verbose: print 'Removing local file/dir', `fullname`
        remove(fullname)
    #
    # Recursively mirror subdirectories
    for subdir in subdirs:
        if interactive:
            doit = askabout('subdirectory', subdir, pwd)
            if not doit: continue
        if verbose: print 'Processing subdirectory', `subdir`
        localsubdir = os.path.join(localdir, subdir)
        pwd = f.pwd()
        if verbose > 1:
            print 'Remote directory now:', `pwd`
            print 'Remote cwd', `subdir`
        try:
            f.cwd(subdir)
        except ftplib.error_perm, msg:
            print "Can't chdir to", `subdir`, ":", `msg`
        else:
            if verbose: print 'Mirroring as', `localsubdir`
            mirrorsubdir(f, localsubdir)
            if verbose > 1: print 'Remote cwd ..'
            f.cwd('..')
        newpwd = f.pwd()
        if newpwd != pwd:
            print 'Ended up in wrong directory after cd + cd ..'
            print 'Giving up now.'
            break
        else:
            if verbose > 1: print 'OK.'

# Helper to remove a file or directory tree
def remove(fullname):
    if os.path.isdir(fullname) and not os.path.islink(fullname):
        try:
            names = os.listdir(fullname)
        except os.error:
            names = []
        ok = 1
        for name in names:
            if not remove(os.path.join(fullname, name)):
                ok = 0
        if not ok:
            return 0
        try:
            os.rmdir(fullname)
        except os.error, msg:
            print "Can't remove local directory %s: %s" % \
                  (`fullname`, str(msg))
            return 0
    else:
        try:
            os.unlink(fullname)
        except os.error, msg:
            print "Can't remove local file %s: %s" % \
                  (`fullname`, str(msg))
            return 0
    return 1

# Wrapper around a file for writing to write a hash sign every block.
class LoggingFile:
    def __init__(self, fp, blocksize, outfp):
        self.fp = fp
        self.bytes = 0
        self.hashes = 0
        self.blocksize = blocksize
        self.outfp = outfp
    def write(self, data):
        self.bytes = self.bytes + len(data)
        hashes = int(self.bytes) / self.blocksize
        while hashes > self.hashes:
            self.outfp.write('#')
            self.outfp.flush()
            self.hashes = self.hashes + 1
        self.fp.write(data)
    def close(self):
        self.outfp.write('\n')

# Ask permission to download a file.
def askabout(filetype, filename, pwd):
    prompt = 'Retrieve %s %s from %s ? [ny] ' % (filetype, filename, pwd)
    while 1:
        reply = raw_input(prompt).strip().lower()
        if reply in ['y', 'ye', 'yes']:
            return 1
        if reply in ['', 'n', 'no', 'nop', 'nope']:
            return 0
        print 'Please answer yes or no.'

# Create a directory if it doesn't exist.  Recursively create the
# parent directory as well if needed.
def makedir(pathname):
    if os.path.isdir(pathname):
        return
    dirname = os.path.dirname(pathname)
    if dirname: makedir(dirname)
    os.mkdir(pathname, 0777)

# Write a dictionary to a file in a way that can be read back using
# rval() but is still somewhat readable (i.e. not a single long line).
# Also creates a backup file.
def writedict(dict, filename):
    dir, fname = os.path.split(filename)
    tempname = os.path.join(dir, '@' + fname)
    backup = os.path.join(dir, fname + '~')
    try:
        os.unlink(backup)
    except os.error:
        pass
    fp = open(tempname, 'w')
    fp.write('{\n')
    for key, value in dict.items():
        fp.write('%s: %s,\n' % (`key`, `value`))
    fp.write('}\n')
    fp.close()
    try:
        os.rename(filename, backup)
    except os.error:
        pass
    os.rename(tempname, filename)


if __name__ == '__main__':
    main()
