import json
import os

import torch
from loguru import logger


class KGForBART:
    def __init__(self, kg_dataset, debug=False):
        self.debug = debug

        dataset_dir = f"data/{kg_dataset}"
        with open(os.path.join(dataset_dir, "kg.json"), encoding="utf-8") as f:
            self.kg = json.load(f)
        with open(os.path.join(dataset_dir, "entity2id.json"), encoding="utf-8") as f:
            self.entity2id = json.load(f)
        with open(os.path.join(dataset_dir, "item_ids.json"), encoding="utf-8") as f:
            self.item_ids = json.load(f)
        with open(os.path.join(dataset_dir, "relation2id.json"), encoding="utf-8") as f:
            self.relation2id = json.load(f)

        self._prepare_kg()

    def _prepare_kg(self):
        edge_list = set()  # [(entity, entity, relation)]
        for entity in self.entity2id.values():
            if str(entity) in self.kg:
                for relation_and_tail in self.kg[str(entity)]:
                    edge_list.add((entity, relation_and_tail[1], relation_and_tail[0]))
                    edge_list.add((relation_and_tail[1], entity, relation_and_tail[0]))
        edge = torch.tensor(list(edge_list), dtype=torch.long)

        self.edge_index = edge[:, :2].T  # (2, n_edge)
        self.edge_type = edge[:, 2]  # (n_edge)
        self.num_relations = len(self.relation2id)
        self.num_entities = len(self.entity2id)

        self.pad_id = self.entity2id["<pad>"] = len(self.entity2id)

        self.id2entity = {idx: ent for ent, idx in self.entity2id.items()}

        if self.debug:
            logger.debug(
                f"#edge: {len(edge)}, #relation: {self.num_relations}, "
                f"#entity: {len(self.entity2id)}"
            )

    def get_kg_info(self):
        kg_info = {
            "edge_index": self.edge_index,
            "edge_type": self.edge_type,
            "num_entities": self.num_entities,
            "num_relations": self.num_relations,
            "entity2id": self.entity2id,
            "id2entity": self.id2entity,
            "item_ids": self.item_ids,
            "pad_id": self.pad_id,
        }
        return kg_info