from collections import defaultdict
import json
import random
import string
from copy import deepcopy
from convlab.policy.policy import Policy

db_path = './hotels_data.json'


def generate_reference_number(length=8):
    letters_and_digits = string.ascii_uppercase + string.digits
    reference_number = ''.join(random.choice(letters_and_digits) for _ in range(length))
    return reference_number

class DialoguePolicy(Policy):
    info_dict = None
    def __init__(self):
        Policy.__init__(self)
        self.db = self.load_database(db_path)

    def load_database(self, db_path):
        with open(db_path, 'r', encoding='utf-8') as f:
            return json.load(f)

    def query(self, domain, constraints):
        if domain != 'hotel':
            return []

        results = []
        for entry in self.db:
            match = all(entry.get(key) == value for key, value in constraints)
            if match:
                results.append(entry)
        return results

    def predict(self, state):
        self.results = []
        system_action = defaultdict(list)
        user_action = defaultdict(list)

        for intent, domain, slot, value in state['user_action']:
            user_action[(domain.lower(), intent.lower())].append((slot.lower(), value))

        for user_act in user_action:
            self.update_system_action(user_act, user_action, state, system_action)

        if any(True for slots in user_action.values() for (slot, _) in slots if
               slot in ['book stay', 'book day', 'book people']):
            if self.results:
                reference_number = generate_reference_number()
                system_action = {('Booking', 'Book'): [["Ref", reference_number]]}

        system_acts = [[intent, domain, slot, value] for (domain, intent), slots in system_action.items() for
                       slot, value in slots]
        state['system_action'] = system_acts
        return system_acts

    def update_system_action(self, user_act, user_action, state, system_action):
        domain, intent = user_act
        constraints = [(slot, value) for slot, value in state['belief_state'][domain]['info'].items() if value != '']
        # print(f"Constraints: {constraints}")
        self.results = deepcopy(self.query(domain.lower(), constraints))
        # print(f"Query results: {self.results}")

        if intent == 'request':
            if len(self.results) == 0:
                system_action[(domain, 'NoOffer')] = []
            else:
                for slot in user_action[user_act]:
                    if slot[0] in self.results[0]:
                        system_action[(domain, 'Inform')].append([slot[0], self.results[0].get(slot[0], 'unknown')])

        elif intent == 'inform':
            if len(self.results) == 0:
                system_action[(domain, 'NoOffer')] = []
            else:
                system_action[(domain, 'Inform')].append(['Choice', str(len(self.results))])
                choice = self.results[0]

                if domain in ["hotel"]:
                    system_action[(domain, 'Recommend')].append(['Name', choice['name']])
                    for slot in state['belief_state'][domain]['info']:
                        if choice.get(slot):
                            state['belief_state'][domain]['info'][slot] = choice[slot]