from abc import ABC
from abc import abstractmethod
from typing import Iterable
from typing import List
from pathlib import Path
from typing import Dict
from typing import Iterable
from typing import List
from typing import Union
import json

import numpy as np

class AbsTokenizer(ABC):
    @abstractmethod
    def text2tokens(self, line: str) -> List[str]:
        raise NotImplementedError

    @abstractmethod
    def tokens2text(self, tokens: Iterable[str]) -> str:
        raise NotImplementedError


class BaseTokenizer(ABC):
    def __init__(self, token_list: Union[Path, str, Iterable[str]]=None,
                 unk_symbol: str = "<unk>",
                 **kwargs,
                 ):
        
        if token_list is not None:
            if isinstance(token_list, (Path, str)) and token_list.endswith(".txt"):
                token_list = Path(token_list)
                self.token_list_repr = str(token_list)
                self.token_list: List[str] = []
                
                with token_list.open("r", encoding="utf-8") as f:
                    for idx, line in enumerate(f):
                        line = line.rstrip()
                        self.token_list.append(line)
            elif isinstance(token_list, (Path, str)) and token_list.endswith(".json"):
                token_list = Path(token_list)
                self.token_list_repr = str(token_list)
                self.token_list: List[str] = []

                with open(token_list, 'r', encoding='utf-8') as f:
                    self.token_list = json.load(f)
                    

            else:
                self.token_list: List[str] = list(token_list)
                self.token_list_repr = ""
                for i, t in enumerate(self.token_list):
                    if i == 3:
                        break
                    self.token_list_repr += f"{t}, "
                self.token_list_repr += f"... (NVocab={(len(self.token_list))})"
            
            self.token2id: Dict[str, int] = {}
            for i, t in enumerate(self.token_list):
                if t in self.token2id:
                    raise RuntimeError(f'Symbol "{t}" is duplicated')
                self.token2id[t] = i
            
            self.unk_symbol = unk_symbol
            if self.unk_symbol not in self.token2id:
                raise RuntimeError(
                    f"Unknown symbol '{unk_symbol}' doesn't exist in the token_list"
                )
            self.unk_id = self.token2id[self.unk_symbol]
    
    def encode(self, text):
        tokens = self.text2tokens(text)
        text_ints = self.tokens2ids(tokens)
        
        return text_ints
    
    def decode(self, text_ints):
        token = self.ids2tokens(text_ints)
        text = self.tokens2text(token)
        return text
    
    def get_num_vocabulary_size(self) -> int:
        return len(self.token_list)
    
    def ids2tokens(self, integers: Union[np.ndarray, Iterable[int]]) -> List[str]:
        if isinstance(integers, np.ndarray) and integers.ndim != 1:
            raise ValueError(f"Must be 1 dim ndarray, but got {integers.ndim}")
        return [self.token_list[i] for i in integers]
    
    def tokens2ids(self, tokens: Iterable[str]) -> List[int]:
        return [self.token2id.get(i, self.unk_id) for i in tokens]
    
    @abstractmethod
    def text2tokens(self, line: str) -> List[str]:
        raise NotImplementedError
    
    @abstractmethod
    def tokens2text(self, tokens: Iterable[str]) -> str:
        raise NotImplementedError