import os, time
import libxml2

from sfatables.globals import sfatables_config
from sfatables.pretty import Pretty
from sfatables.command import Command

class List(Command):
    
    def __init__(self):
        self.options = [('-L','--list')]
        self.help = 'List a chain'
        self.key='list_rule'
        self.matches = False
        self.targets = False

        return

    def get_info(self, type, xmlextension_path):
        xmldoc = libxml2.parseFile(xmlextension_path)
        p = xmldoc.xpathNewContext()
        
        ext_name_node = p.xpathEval("/%s/@name"%type)
        ext_name = ext_name_node[0].content

        name_nodes = p.xpathEval("//rule/argument[value!='']/name")
        value_nodes = p.xpathEval("//rule/argument[value!='']/value")
        element_nodes = p.xpathEval("//argument[value!='']/parent::rule/@element")

        if (len(element_nodes)>1):
            raise Exception("Invalid rule %s contains multiple elements."%xmlextension_path)

        element = []
        argument_str = ""
        if element_nodes:
            element = element_nodes[0].content

            names = [n.content for n in name_nodes]
            values = [v.content for v in value_nodes]

            name_values = list(zip(names,values))
            name_value_pairs = [n_v[0]+'='+n_v[1] for n_v in name_values]

            argument_str = ",".join(name_value_pairs)

        p.xpathFreeContext()
        xmldoc.freeDoc()

        return {'name':ext_name, 'arguments':argument_str, 'element':element}

    def get_rule_list(self, chain_dir_path):
        broken_semantics = os.walk(chain_dir_path)
        rule_numbers = {}

        for (root, dirs, files) in broken_semantics:
            for file in files:
                if (file.startswith('sfatables')):
                    (magic,number,type) = file.split('-')
                    rule_numbers[int(number)]=1

        rule_list = list(rule_numbers.keys())
        rule_list.sort()
        return rule_list

    def call(self, command_options, match_options, target_options):
        if (len(command_options.args) < 1):
            print("Please specify the name of the chain you would like to list, e.g. sfatables -L INCOMING.")
            return

        chain = command_options.args[0]
        chain_dir = os.path.join(sfatables_config, chain)

        rule_list = self.get_rule_list(chain_dir)

        pretty = Pretty(['Rule','Match','Arguments','Target','Element','Arguments'])

        for number in rule_list:
            match_file = "sfatables-%d-%s"%(number,'match')
            target_file = "sfatables-%d-%s"%(number,'target')

            match_path = sfatables_config + '/' + chain + '/' + match_file
            target_path = sfatables_config + '/' + chain + '/' + target_file

            match_info = self.get_info ('match',match_path)
            target_info = self.get_info ('target',target_path)

            pretty.push_row(["%d"%number,
                             match_info['name'],
                             match_info['arguments'],
                             target_info['name'],
                             target_info['element'],
                             target_info['arguments']])

        pretty.pprint()