import os
import shutil
import logging
import errno
import sys

from wizard import command, deploy, shell, util

def main(argv, baton):
    options, args = parse_args(argv, baton)
    dir = args[0]
    command.chdir(dir)

    shell.drop_priviledges(options)

    logging.debug("uid is %d" % os.getuid())

    check_if_already_migrated(options)

    deployment = make_deployment() # uses chdir
    version = deployment.app_version
    repo    = version.application.repository(options.srv_path)
    tag     = version.scripts_tag

    os.unsetenv("GIT_DIR") # prevent some perverse errors

    sh = shell.Shell(options.dry_run)
    check_if_tag_exists(sh, repo, tag)
    make_repository(sh, options, repo, tag)
    check_variables(deployment, options)

    if not options.dry_run:
        deployment.scriptsifyVersion()
        os.rename(".scripts-version", ".scripts/old-version") # archive
    else:
        logging.info("# create .scripts/version containing \"%s-%s-scripts\"" % (deployment.application.name, deployment.version))
        logging.info("mv .scripts-version .scripts/old-version")

def parse_args(argv, baton):
    usage = """usage: %prog migrate [ARGS] DIR

Migrates a directory to our Git-based autoinstall format.
Performs basic sanity checking and intelligently determines
what repository and tag to use.

This command is meant to be run as the owner of the install
it is upgrading (see the scripts AFS kernel patch).  Do
NOT run this command as root."""
    parser = command.WizardOptionParser(usage)
    baton.push(parser, "srv_path")
    parser.add_option("--dry-run", dest="dry_run", action="store_true",
            default=False, help="Prints would would be run without changing anything")
    parser.add_option("--force", "-f", dest="force", action="store_true",
            default=False, help="If .git or .scripts directory already exists, delete them and migrate")
    options, args = parser.parse_all(argv)
    if len(args) > 1:
        parser.error("too many arguments")
    elif not args:
        parser.error("must specify directory")
    return (options, args)

def check_if_already_migrated(options):
    # XXX: duplicates some logic with Deployment.migrated
    if os.path.isdir(".git") or os.path.isdir(".scripts"):
        if not options.force:
            raise AlreadyMigratedError(dir)
        else:
            if os.path.isdir(".git"):
                logging.warning("Force removing .git directory")
                if not options.dry_run: shutil.rmtree(".git")
            if os.path.isdir(".scripts"):
                logging.warning("Force removing .scripts directory")
                if not options.dry_run: shutil.rmtree(".scripts")

def make_deployment():
    try:
        return deploy.Deployment(".")
    except IOError as e:
        if e.errno == errno.ENOENT:
            raise NotAutoinstallError(dir)
        else: raise e

def check_if_tag_exists(sh, repo, tag):
    # check if the version we're trying to convert exists. We assume
    # a convention here, namely, v1.2.3-scripts is what we want. If
    # you broke the convention... shame on you.
    try:
        sh.call("git", "--git-dir", repo, "rev-parse", tag)
    except shell.CallError:
        raise NoTagError(version)

def make_repository(sh, options, repo, tag):
    sh.call("git", "init") # create repository
    # configure our alternates (to save space and make this quick)
    data = os.path.join(repo, "objects")
    file = ".git/objects/info/alternates"
    if not options.dry_run:
        alternates = open(file, "w")
        alternates.write(data)
        alternates.close()
        htaccess = open(".git/.htaccess", "w")
        htaccess.write("Deny from all\n")
        htaccess.close()
    else:
        logging.info("# create %s containing \"%s\"" % (file, data))
        logging.info('# create .htaccess containing "Deny from all"')
    # configure our remote (this is merely for convenience; wizard scripts
    # will not rely on this)
    sh.call("git", "remote", "add", "origin", repo)
    # configure what would normally be set up on a 'git clone' for consistency
    sh.call("git", "config", "branch.master.remote", "origin")
    sh.call("git", "config", "branch.master.merge", "refs/heads/master")
    # perform the initial fetch
    sh.call("git", "fetch", "origin")
    # soft reset to our tag
    sh.call("git", "reset", tag, "--")
    # checkout the .scripts directory
    sh.call("git", "checkout", ".scripts")
    # commit user local changes
    message = "Autoinstall migration of %s locker.\n\n%s" % (util.get_dir_owner(), util.get_git_footer())
    util.set_git_env()
    try:
        message += "\nMigrated-by: " + util.get_operator_git()
    except util.NoOperatorInfo:
        pass
    sh.call("git", "commit", "--allow-empty", "-a", "-m", message)
    # for verbose purposes, give us a git status and git diff
    if options.verbose:
        try:
            sh.call("git", "status")
        except shell.CallError:
            pass
        try:
            sh.call("git", "diff")
        except shell.CallError:
            pass

def check_variables(d, options):
    """Attempt to extract variables and complain if some are missing."""
    variables = d.extract()
    for k,v in variables.items():
        if v is None and k not in d.application.deprecated_keys:
            logging.warning("Variable %s not found" % k)
        else:
            logging.debug("Variable %s is %s" % (k,v))

class Error(command.Error):
    """Base exception for all exceptions raised by migrate"""
    pass

class AlreadyMigratedError(Error):
    def __init__(self, dir):
        self.dir = dir
    def __str__(self):
        return """

ERROR: Directory already contains a .git and/or
.scripts directory.  Did you already migrate it?
"""

class NotAutoinstallError(Error):
    def __init__(self, dir):
        self.dir = dir
    def __str__(self):
        return """

ERROR: Could not find .scripts-version file. Are you sure
this is an autoinstalled application?
"""

class NoTagError(Error):
    def __init__(self, version):
        self.version = version
    def __str__(self):
        return """

ERROR: Could not find tag v%s-scripts in repository
for %s.  Double check and make sure
the repository was prepared with all necessary tags!
""" % (self.version.version, self.version.application.name)