#!/bin/env python

# Interactively prompts for variable values
# expected arguments are
# command -d [default-xml [custom-xml [ consolidated-xml ]]]

# we use 3 instances of PLCConfiguration throughout:
# cdef : models the defaults, from plc_default.xml
# cread : merged from plc_default & configs/site.xml
# cwrite : site.xml + pending changes

import sys
import os
import re
import readline
import traceback
from optparse import OptionParser

from plc_config import PLCConfiguration
from plc_config import ConfigurationException

####################
release_id = "$Id$"
release_rev = "$Revision$"
release_url = "$URL$"

def validator (validated_variables):
    maint_user = validated_variables["PLC_API_MAINTENANCE_USER"]
    root_user = validated_variables["PLC_ROOT_USER"]
    if maint_user == root_user:
        raise ConfigurationException("PLC_API_MAINTENANCE_USER=%s cannot be the same as PLC_ROOT_USER=%s"%(maint_user,root_user))

# historically we could also configure the devel pkg....
globals = {
    'def_default_config' : "/etc/planetlab/default_config.xml",
    'def_site_config' : "/etc/planetlab/configs/site.xml",
    'def_consolidated_config' : "/etc/planetlab/plc_config.xml",
    'usual_variables': ["PLC_NAME",
                        "PLC_SHORTNAME",
                        "PLC_SLICE_PREFIX",
                        "PLC_ROOT_USER",
                        "PLC_ROOT_PASSWORD",
                        "PLC_MAIL_ENABLED",
                        "PLC_MAIL_SUPPORT_ADDRESS",
                        "PLC_DB_HOST",
                        "PLC_API_HOST",
                        "PLC_WWW_HOST",
                        "PLC_BOOT_HOST",
                        "PLC_NET_DNS1",
                        "PLC_NET_DNS2",
                        ],
    }

def usage ():
    command_usage="%prog [options] [default-xml [site-xml [consolidated-xml]]]"
    global globals
    command_usage +="""
\t default-xml defaults to %s
\t site-xml defaults to %s
\t consolidated-xml defaults to %s""" % (globals['def_default_config'],
                                         globals['def_site_config'], 
                                         globals['def_consolidated_config'])
    return command_usage

####################
def get_value (config,  category_id, variable_id):
    (category, variable) = config.get (category_id, variable_id)
    return variable['value']

def get_current_value (cread, cwrite, category_id, variable_id):
    # the value stored in cwrite, if present, is the one we want
    try:
        result=get_value (cwrite,category_id,variable_id)
    except:
        result=get_value (cread,category_id,variable_id)
    return result

# refrain from using plc_config's _sanitize 
def get_varname (config,  category_id, variable_id):
    (category, variable) = config.get (category_id, variable_id)
    return (category_id+"_"+variable['id']).upper()

# could not avoid using _sanitize here..
def get_name_comments (config, cid, vid):
    try:
        (category, variable) = config.get (cid, vid)
        (id, name, value, comments) = config._sanitize_variable (cid,variable)
        return (name,comments)
    except:
        return (None,[])

def print_name_comments (config, cid, vid):
    (name,comments)=get_name_comments(config,cid,vid)
    if name:
        print "### %s" % name
    if comments:
        for line in comments:
            print "# %s" % line
    else:
        print "!!! No comment associated to %s_%s" % (cid,vid)

####################
def list_categories (config):
    result=[]
    for (category_id, (category, variables)) in config.variables().iteritems():
        result += [category_id]
    return result

def print_categories (config):
    print "Known categories"
    for cid in list_categories(config):
        print "%s" % (cid.upper())

####################
def list_category (config, cid):
    result=[]
    for (category_id, (category, variables)) in config.variables().iteritems():
        if (cid == category_id):
            for variable in variables.values():
                result += ["%s_%s" %(cid,variable['id'])]
    return result
    
def print_category (config, cid, show_comments=True):
    cid=cid.lower()
    CID=cid.upper()
    vids=list_category(config,cid)
    if (len(vids) == 0):
        print "%s : no such category"%CID
    else:
        print "Category %s contains" %(CID)
        for vid in vids:
            print vid.upper()

####################
def consolidate (default_config, site_config, consolidated_config):
    try:
        conso = PLCConfiguration (default_config)
        conso.load (site_config)
        conso.save (consolidated_config)
    except Exception, inst:
        print "Could not consolidate, %s" % (str(inst))
        return
    print ("Merged\n\t%s\nand\t%s\ninto\t%s"%(default_config,site_config,
                                              consolidated_config))

def reload_service ():
    os.system("set -x ; service plc reload")
        
####################
def restart_service ():
    print ("==================== Stopping plc" )
    os.system("service plc stop" )
    print ("==================== Starting plc" )
    os.system("service plc start")

####################
def prompt_variable (cdef, cread, cwrite, category, variable,
                     show_comments, support_next=False):

    assert category.has_key('id')
    assert variable.has_key('id')

    category_id = category ['id']
    variable_id = variable['id']

    while True:
        default_value = get_value(cdef,category_id,variable_id)
        current_value = get_current_value(cread,cwrite,category_id, variable_id)
        varname = get_varname (cread,category_id, variable_id)
        
        if show_comments :
            print_name_comments (cdef, category_id, variable_id)
        prompt = "== %s : [%s] " % (varname,current_value)
        try:
            answer = raw_input(prompt).strip()
        except EOFError :
            raise Exception ('BailOut')
        except KeyboardInterrupt:
            print "\n"
            raise Exception ('BailOut')

        # no change
        if (answer == "") or (answer == current_value):
            return None
        elif (answer == "."):
            raise Exception ('BailOut')
        elif (answer == "#"):
            print_name_comments(cread,category_id,variable_id)
        elif (answer == "?"):
            variable_usage = """Edit Commands :
#\tShow variable comments
.\tStops prompting, return to mainloop
/\tCleans any site-defined value, reverts to default
=\tShows default value
>\tSkips to next category
?\tThis help
"""
            print variable_usage.strip()
        elif (answer == "="):
            print ("%s defaults to %s" %(varname,default_value))
        # revert to default : remove from cwrite (i.e. site-config)
        elif (answer == "/"):
            cwrite.delete(category_id,variable_id)
            print ("%s reverted to %s" %(varname,default_value))
            return
        elif (answer == ">"):
            if support_next:
                raise Exception ('NextCategory')
            else:
                print "No support for next category"
        else:
            variable['value'] = answer
            cwrite.set(category,variable)
            return

def prompt_variables_all (cdef, cread, cwrite, show_comments):
    try:
        for (category_id, (category, variables)) in cread.variables().iteritems():
            print ("========== Category = %s" % category_id.upper())
            for variable in variables.values():
                try:
                    newvar = prompt_variable (cdef, cread, cwrite, category, variable,
                                              show_comments, True)
                except Exception, inst:
                    if (str(inst) == 'NextCategory'): break
                    else: raise
                    
    except Exception, inst:
        if (str(inst) == 'BailOut'): return
        else: raise

def prompt_variables_category (cdef, cread, cwrite, cid, show_comments):
    cid=cid.lower()
    CID=cid.upper()
    try:
        print ("========== Category = %s" % CID)
        for vid in list_category(cdef,cid):
            (category,variable) = cdef.locate_varname(vid.upper())
            newvar = prompt_variable (cdef, cread, cwrite, category, variable,
                                      show_comments, False)
    except Exception, inst:
        if (str(inst) == 'BailOut'): return
        else: raise

####################
def show_variable (cdef, cread, cwrite,
                   category, variable,show_value,show_comments):
    assert category.has_key('id')
    assert variable.has_key('id')

    category_id = category ['id']
    variable_id = variable['id']

    default_value = get_value(cdef,category_id,variable_id)
    current_value = get_current_value(cread,cwrite,category_id,variable_id)
    varname = get_varname (cread,category_id, variable_id)
    if show_comments :
        print_name_comments (cdef, category_id, variable_id)
    if show_value:
        print "%s = %s" % (varname,current_value)
    else:
        print "%s" % (varname)

def show_variables_all (cdef, cread, cwrite, show_value, show_comments):
    for (category_id, (category, variables)) in cread.variables().iteritems():
        print ("========== Category = %s" % category_id.upper())
        for variable in variables.values():
            show_variable (cdef, cread, cwrite,
                           category, variable,show_value,show_comments)

def show_variables_category (cdef, cread, cwrite, cid, show_value,show_comments):
    cid=cid.lower()
    CID=cid.upper()
    print ("========== Category = %s" % CID)
    for vid in list_category(cdef,cid):
        (category,variable) = cdef.locate_varname(vid.upper())
        show_variable (cdef, cread, cwrite, category, variable,
                       show_value,show_comments)

####################
re_mainloop_0arg="^(?P<command>[uUwrRqlLsSeEcvVhH\?])[ \t]*$"
re_mainloop_1arg="^(?P<command>[sSeEvV])[ \t]+(?P<arg>\w+)$"
matcher_mainloop_0arg=re.compile(re_mainloop_0arg)
matcher_mainloop_1arg=re.compile(re_mainloop_1arg)

def mainloop (cdef, cread, cwrite, default_config, site_config, consolidated_config):
    while True:
        try:
            answer = raw_input("Enter command (u for usual changes, w to save, ? for help) ").strip()
        except EOFError:
            answer =""
        except KeyboardInterrupt:
            print "\nBye"
            sys.exit()

        if (answer == "") or (answer in "?hH"):
            mainloop_usage = """Available commands:
 Uppercase versions give variables comments, when available
 u/U\t\t\tEdit usual variables
 w/W\t\t\tWrite / Write & reload
 r\t\t\tRestart plc service
 q\t\t\tQuit (without saving)
 h/?\t\t\tThis help
---
 l/L [<cat>|<var>]\tShow Locally modified variables/values
 s/S [<cat>|<var>]\tShow variables/values (all, in category, single)
 e/E [<cat>|<var>]\tEdit variables (all, in category, single)
---
 c\t\t\tList categories
 v/V [<cat>|<var>]List Variables (all, in category, single)
---
Typical usage involves: u, [l,] w, r, q
"""
            print mainloop_usage
            continue
        groups_parse = matcher_mainloop_0arg.match(answer)
        command=None
        if (groups_parse):
            command = groups_parse.group('command')
            arg=None
        else:
            groups_parse = matcher_mainloop_1arg.match(answer)
            if (groups_parse):
                command = groups_parse.group('command')
                arg=groups_parse.group('arg')
        if not command:
            print ("Unknown command >%s< -- use h for help" % answer)
            continue

        show_comments=command.isupper()
        command=command.lower()

        mode='ALL'
        if arg:
            mode=None
            arg=arg.lower()
            variables=list_category (cdef,arg)
            if len(variables):
                # category_id as the category name
                # variables as the list of variable names
                mode='CATEGORY'
                category_id=arg
            arg=arg.upper()
            (category,variable)=cdef.locate_varname(arg)
            if variable:
                # category/variable as output by locate_varname
                mode='VARIABLE'
            if not mode:
                print "%s: no such category or variable" % arg
                continue

        if (command in "qQ"):
            # todo check confirmation
            return
        elif (command == "w"):
            global defined_flavour
            try:
                # Confirm that various constraints are met before saving file.
                validate_variables = {"PLC_API":"MAINTENANCE_USER","PLC":"ROOT_USER"}
                validated_variables = cwrite.verify(cdef, cread, validate_variables)
                validator(validated_variables)
                cwrite.save(site_config)
            except ConfigurationException, e:
                print "Save failed due to a configuration exception: %s" % e
                break;
            except:
                print traceback.print_exc()
                print ("Could not save -- fix write access on %s" % site_config)
                break
            print "Wrote",site_config
            consolidate(default_config, site_config, consolidated_config)
            print "You might want to type 'r' (restart plc), 'R' (reload plc) or 'q' (quit)"
        elif (command == "u"):
            try:
                global globals
                for varname in globals['usual_variables']:
                    (category,variable) = cdef.locate_varname(varname)
                    prompt_variable(cdef, cread, cwrite, category, variable, False)
            except Exception, inst:
                if (str(inst) != 'BailOut'):
                    raise
        elif (command == "r"):
            restart_service()
        elif (command == "R"):
            reload_service()
        elif (command == "c"):
            print_categories(cread)
        elif (command in "eE"):
            if mode == 'ALL':
                prompt_variables_all(cdef, cread, cwrite,show_comments)
            elif mode == 'CATEGORY':
                prompt_variables_category(cdef,cread,cwrite,category_id,show_comments)
            elif mode == 'VARIABLE':
                try:
                    prompt_variable (cdef,cread,cwrite,category,variable,
                                     show_comments,False)
                except Exception, inst:
                    if (str(inst) != 'BailOut'):
                        raise
        elif (command in "vVsSlL"):
            show_value=(command in "sSlL")
            (c1,c2,c3) = (cdef, cread, cwrite)
            if (command in "lL"):
                (c1,c2,c3) = (cwrite,cwrite,cwrite)
            if mode == 'ALL':
                show_variables_all(c1,c2,c3,show_value,show_comments)
            elif mode == 'CATEGORY':
                show_variables_category(c1,c2,c3,category_id,show_value,show_comments)
            elif mode == 'VARIABLE':
                show_variable (c1,c2,c3,category,variable,show_value,show_comments)
        else:
            print ("Unknown command >%s< -- use h for help" % answer)

####################
# creates directory for file if not yet existing
def check_dir (config_file):
    dirname = os.path.dirname (config_file)
    if (not os.path.exists (dirname)):
        try:
            os.makedirs(dirname,0755)
        except OSError, e:
            print "Cannot create dir %s for file %s - error=[%s] - exiting" % (dirname,config_file,e)
            sys.exit(1)
            
        if (not os.path.exists (dirname)):
            print "Cannot create dir %s for file %s - exiting" % (dirname,config_file)
            sys.exit(1)
        else:
            print "Created directory %s" % dirname
                
####################
def main ():

    parser = OptionParser(usage=usage(), version="%prog " + release_rev + release_url)
    (config,args) = parser.parse_args()
    if len(args)>3:
        parser.error("too many arguments")

    # use any provided arg as advertised
    global globals
    (default_config,site_config,consolidated_config) = (globals['def_default_config'],
                                                        globals['def_site_config'],
                                                        globals['def_consolidated_config'])
    if len(args) >= 1:
        default_config=args[0]
    if len(args) >= 2:
        site_config=args[1]
    if len(args) == 3:
        consolidated_config=args[2]

    for c in (default_config,site_config,consolidated_config):
        check_dir (c)

    try:
        # the default settings only - read only
        cdef = PLCConfiguration(default_config)

        # in effect : default settings + local settings - read only
        cread = PLCConfiguration(default_config)

    except ConfigurationException, e:
        print ("Error %s in default config file %s" %(e,default_config))
        return 1
    except:
        print traceback.print_exc()
        print ("default config files %s not found, is myplc installed ?" % default_config)
        return 1


    # local settings only, will be modified & saved
    cwrite=PLCConfiguration()
    
    try:
        cread.load(site_config)
        cwrite.load(site_config)
    except:
        cwrite = PLCConfiguration()

    mainloop (cdef, cread, cwrite, default_config, site_config, consolidated_config)
    return 0

if __name__ == '__main__':
    main()