import json
import random
import itertools
import difflib
from copy import deepcopy

from app.core.config import FASHION_CATEGORIES, FASHION_CATEGORIES_MAPPING


# Helper function to calculate the edit distance similarity between two file names
def sim_score(a, b):
    return difflib.SequenceMatcher(None, a, b).ratio()


class FashionDataset(object):
    fashion_categories = json.load(open(FASHION_CATEGORIES, "r"))
    fashion_categories_mapping = json.load(open(FASHION_CATEGORIES_MAPPING, "r"))

    def __init__(self, item_metadata):
        self.item_metadat = item_metadata
        self.item2cate = self.get_item2cate(item_metadata)
        self.cate2item = self.get_cate2item(item_metadata)
        self.cate2num = {k: len(v) for k, v in self.cate2item.items()}

    # def generate_outfit(self, query_item, topk, max_outfits):
    #     query_item["mapped_cate"] = self.fashion_categories_mapping[query_item["semantic_category"]]
    #     possible_outfits = self.count_possible(query_item["mapped_cate"])
    #
    #     if possible_outfits < topk:
    #         raise ValueError(f"Cannot generate more than {topk} outfits!")
    #
    #     outfit_list = self.get_possible_outfit(query_item)
    #     if possible_outfits > max_outfits:
    #         outfit_list = random.sample(outfit_list, max_outfits)
    #     return outfit_list

    def count_possible(self, given_cate):
        possible = 0
        if given_cate == 'tops':
            if self.cate2num['outerwear'] == 0:
                possible = self.cate2num['bottoms']
            else:
                possible = self.cate2num['bottoms'] * self.cate2num['outerwear']
        elif given_cate == 'bottoms':
            if self.cate2num['outerwear'] == 0:
                possible = self.cate2num['tops']
            else:
                possible = self.cate2num['tops'] * self.cate2num['outerwear']
        elif given_cate == 'outerwear':
            possible = self.cate2num['tops'] * self.cate2num['bottoms'] + self.cate2num['all-body']
        elif given_cate == 'all-body':
            possible = self.cate2num['outerwear']
        return possible

    def generate_outfit(self, query_item, topk, max_outfits):
        query_item["mapped_cate"] = self.fashion_categories_mapping[query_item["semantic_category"]]
        given_cate = query_item["mapped_cate"]

        if given_cate == 'tops' or given_cate == "bottoms":
            complementary_cate = "bottoms" if given_cate == "tops" else "tops"
            # check bottom num
            if complementary_cate not in self.cate2num.keys() or not self.cate2num[complementary_cate]:
                raise ValueError(f"Not enough {complementary_cate} available to generate outfits.")

            complementary_items = deepcopy(self.cate2item[complementary_cate])
            sim_scores = [sim_score(item["item_name"], query_item["item_name"]) for item in complementary_items]
            outfit_list = []
            used_items = set()

            while len(outfit_list) < max_outfits:
                if not complementary_items:
                    break

                # 根据权重从bottoms中选择一个元素
                item_index = random.choices(range(len(complementary_items)), weights=sim_scores)[0]
                item = complementary_items.pop(item_index)
                sim_scores.pop(item_index)

                if item["item_name"] not in used_items:
                    used_items.add(item["item_name"])
                    outfit = [query_item, item]
                    outfit_list.append(tuple(outfit))
                    if "outerwear" in self.cate2item.keys():
                        # 20% chance to include an outerwear
                        if self.cate2num['outerwear'] > 0 and random.random() < 0.2:
                            outerwear = random.choice(self.cate2item['outerwear'])
                            outfit.append(outerwear)
                            outfit_list.append(tuple(outfit))
            # if len(outfit_list) < topk:
            #     raise ValueError(f"Cannot generate more than {topk} outfits!")

            return outfit_list
        elif given_cate == 'outerwear':
            top_bottom_combination = [(x[0], x[1]) for x in
                                      itertools.product(self.cate2item['tops'], self.cate2item['bottoms'])]
            sim_scores = [sim_score(x[0]["item_name"], x[1]["item_name"]) for x in top_bottom_combination]
            outfit_list = []
            used_items = set()

            while len(outfit_list) < max_outfits:
                if not top_bottom_combination:
                    break

                # 根据权重从top bottom的组合中选择一个，根据top和bottom之间的文件名相似度选择
                top_bottom_index = random.choices(range(len(top_bottom_combination)), weights=sim_scores)[0]
                top_bottom = top_bottom_combination.pop(top_bottom_index)
                sim_scores.pop(top_bottom_index)

                top_name, bottom_name = top_bottom[0]["item_name"], top_bottom[1]["item_name"]
                if top_name + bottom_name not in used_items:
                    used_items.add(top_name + bottom_name)
                    outfit = [query_item] + list(top_bottom)
                    outfit_list.append(tuple(outfit))

            # if len(outfit_list) < topk:
            #     raise ValueError(f"Cannot generate more than {topk} outfits!")

            return outfit_list
        elif given_cate == 'all-body':
            outfit_list = [(query_item, x) for x in self.cate2item['outerwear']]
            return outfit_list

    def get_item2cate(self, item_metadata):
        item2cate = {}
        for metadata in item_metadata:
            cate = metadata["semantic_category"]
            mapped_cate = self.fashion_categories_mapping[cate]
            item2cate[metadata["item_name"]] = mapped_cate
        return item2cate

    def get_cate2item(self, item_metadata):
        cate2item = {}
        for metadata in item_metadata:
            cate = metadata["semantic_category"]
            mapped_cate = self.fashion_categories_mapping[cate]
            metadata["mapped_cate"] = mapped_cate
            if mapped_cate not in cate2item.keys():
                cate2item[mapped_cate] = [metadata]
            else:
                cate2item[mapped_cate].append(metadata)
        return cate2item