# vi: ts=4 expandtab
#
#    Copyright (C) 2009-2010 Canonical Ltd.
#
#    Author: Scott Moser <scott.moser@canonical.com>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License version 3, as
#    published by the Free Software Foundation.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
import yaml
import os
import os.path
import errno
import subprocess
from Cheetah.Template import Template
import cloudinit
import urllib2
import logging
import traceback
import re

WARN = logging.WARN
DEBUG = logging.DEBUG
INFO = logging.INFO

def read_conf(fname):
    try:
	    stream = open(fname,"r")
	    conf = yaml.load(stream)
	    stream.close()
	    return conf
    except IOError as e:
        if e.errno == errno.ENOENT:
            return { }
        raise

def get_base_cfg(cfgfile,cfg_builtin="", parsed_cfgs=None):
    kerncfg = { }
    syscfg = { }
    if parsed_cfgs and cfgfile in parsed_cfgs:
        return(parsed_cfgs[cfgfile])

    contents = read_file_with_includes(cfgfile)
    if contents:
        syscfg = yaml.load(contents)

    kern_contents = read_cc_from_cmdline()
    if kern_contents:
        kerncfg = yaml.load(kern_contents)

    # kernel parameters override system config
    combined = mergedict(kerncfg, syscfg)

    if cfg_builtin:
        builtin = yaml.load(cfg_builtin)
        fin = mergedict(combined,builtin)
    else:
        fin = combined

    if parsed_cfgs != None:
        parsed_cfgs[cfgfile] = fin
    return(fin)

def get_cfg_option_bool(yobj, key, default=False):
    if not yobj.has_key(key): return default
    val = yobj[key]
    if val is True: return True
    if str(val).lower() in [ 'true', '1', 'on', 'yes']:
        return True
    return False

def get_cfg_option_str(yobj, key, default=None):
    if not yobj.has_key(key): return default
    return yobj[key]

def get_cfg_option_list_or_str(yobj, key, default=None):
    if not yobj.has_key(key): return default
    if isinstance(yobj[key],list): return yobj[key]
    return([yobj[key]])

# merge values from src into cand.
# if src has a key, cand will not override
def mergedict(src,cand):
    if isinstance(src,dict) and isinstance(cand,dict):
        for k,v in cand.iteritems():
            if k not in src:
                src[k] = v
            else:
                src[k] = mergedict(src[k],v)
    return src

def write_file(file,content,mode=0644,omode="wb"):
        try:
            os.makedirs(os.path.dirname(file))
        except OSError as e:
            if e.errno != errno.EEXIST:
                raise e

        f=open(file,omode)
        if mode != None:
            os.chmod(file,mode)
        f.write(content)
        f.close()

# get keyid from keyserver
def getkeybyid(keyid,keyserver):
   shcmd="""
   k=${1} ks=${2};
   exec 2>/dev/null
   [ -n "$k" ] || exit 1;
   armour=$(gpg --list-keys --armour "${k}")
   if [ -z "${armour}" ]; then
      gpg --keyserver ${ks} --recv $k >/dev/null &&
         armour=$(gpg --export --armour "${k}") &&
         gpg --batch --yes --delete-keys "${k}"
   fi
   [ -n "${armour}" ] && echo "${armour}"
   """
   args=['sh', '-c', shcmd, "export-gpg-keyid", keyid, keyserver]
   return(subp(args)[0])

def subp(args, input=None):
    s_in = None
    if input is not None:
        s_in = subprocess.PIPE
    sp = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=s_in)
    out,err = sp.communicate(input)
    if sp.returncode is not 0:
        raise subprocess.CalledProcessError(sp.returncode,args)
    return(out,err)

def render_to_file(template, outfile, searchList):
    t = Template(file='/etc/cloud/templates/%s.tmpl' % template, searchList=[searchList])
    f = open(outfile, 'w')
    f.write(t.respond())
    f.close()

def render_string(template, searchList):
    return(Template(template, searchList=[searchList]).respond())


# read_optional_seed
# returns boolean indicating success or failure (presense of files)
# if files are present, populates 'fill' dictionary with 'user-data' and
# 'meta-data' entries
def read_optional_seed(fill,base="",ext="", timeout=2):
    try:
        (md,ud) = read_seeded(base,ext,timeout)
        fill['user-data']= ud
        fill['meta-data']= md
        return True
    except OSError, e:
        if e.errno == errno.ENOENT:
            return False
        raise
    

# raise OSError with enoent if not found
def read_seeded(base="", ext="", timeout=2):
    if base.startswith("/"):
        base="file://%s" % base

    if base.find("%s") >= 0:
        ud_url = base % ("user-data" + ext)
        md_url = base % ("meta-data" + ext)
    else:
        ud_url = "%s%s%s" % (base, "user-data", ext)
        md_url = "%s%s%s" % (base, "meta-data", ext)

    try:
        md_resp = urllib2.urlopen(urllib2.Request(md_url), timeout=timeout)
        ud_resp = urllib2.urlopen(urllib2.Request(ud_url), timeout=timeout)

        md_str = md_resp.read()
        ud = ud_resp.read()
        md = yaml.load(md_str)

        return(md,ud)
    except urllib2.HTTPError:
        raise
    except urllib2.URLError, e:
        if isinstance(e.reason,OSError) and e.reason.errno == errno.ENOENT:
           raise e.reason 
        raise e

def logexc(log,lvl=logging.DEBUG):
    log.log(lvl,traceback.format_exc())

class RecursiveInclude(Exception):
    pass

def read_file_with_includes(fname, rel = ".", stack=[], patt = None):
    if not fname.startswith("/"):
        fname = os.sep.join((rel, fname))

    fname = os.path.realpath(fname)

    if fname in stack:
        raise(RecursiveInclude("%s recursively included" % fname))
    if len(stack) > 10:
        raise(RecursiveInclude("%s included, stack size = %i" %
                               (fname, len(stack))))

    if patt == None:
        patt = re.compile("^#(opt_include|include)[ \t].*$",re.MULTILINE)

    try:
        fp = open(fname)
        contents = fp.read()
        fp.close()
    except:
        raise

    rel = os.path.dirname(fname)
    stack.append(fname)

    cur = 0
    clen = len(contents)
    while True:
        match = patt.search(contents[cur:])
        if not match: break
        loc = match.start() + cur
        endl = match.end() + cur

        (key, cur_fname) = contents[loc:endl].split(None,2)
        cur_fname = cur_fname.strip()

        try:
            inc_contents = read_file_with_includes(cur_fname, rel, stack, patt)
        except IOError, e:
            if e.errno == errno.ENOENT and key == "#opt_include":
                inc_contents = ""
            else:
                raise
        contents = contents[0:loc] + inc_contents + contents[endl+1:]
	cur = loc + len(inc_contents)
    stack.pop()
    return(contents)

def get_cmdline():
    if 'DEBUG_PROC_CMDLINE' in os.environ:
        cmdline = os.environ["DEBUG_PROC_CMDLINE"]
    else:
        try:
            cmdfp = open("/proc/cmdline")
            cmdline = cmdfp.read().strip()
            cmdfp.close()
        except:
            cmdline = ""
    return(cmdline)
	
def read_cc_from_cmdline(cmdline=None):
    # this should support reading cloud-config information from
    # the kernel command line.  It is intended to support content of the
    # format:
    #  cc: <yaml content here> [end_cc]
    # this would include:
    # cc: ssh_import_id: [smoser, kirkland]\\n
    # cc: ssh_import_id: [smoser, bob]\\nruncmd: [ [ ls, -l ], echo hi ] end_cc
    # cc:ssh_import_id: [smoser] end_cc cc:runcmd: [ [ ls, -l ] ] end_cc
    if cmdline is None:
        cmdline = get_cmdline()

    tag_begin="cc:"
    tag_end="end_cc"
    begin_l = len(tag_begin)
    end_l = len(tag_end)
    clen = len(cmdline)
    tokens = [ ]
    begin = cmdline.find(tag_begin)
    while begin >= 0:
        end = cmdline.find(tag_end, begin + begin_l)
        if end < 0:
            end = clen
        tokens.append(cmdline[begin+begin_l:end].lstrip().replace("\\n","\n"))
        
        begin = cmdline.find(tag_begin, end + end_l)

    return('\n'.join(tokens))

def ensure_dirs(dirlist, mode=0755):
    fixmodes = []
    for d in dirlist:
        try:
            if mode != None:
                os.makedirs(d)
            else:
                os.makedirs(d, mode)
        except OSError as e:
            if e.errno != errno.EEXIST: raise
            if mode != None: fixmodes.append(d)

    for d in fixmodes:
        os.chmod(d, mode)

def chownbyname(fname,user=None,group=None):
   uid = -1
   gid = -1
   if user == None and group == None: return
   if user:
      import pwd
      uid = pwd.getpwnam(user).pw_uid
   if group:
      import grp
      gid = grp.getgrnam(group).gr_gid

   os.chown(fname,uid,gid)