import hashlib
from typing import Dict
import os
from pathlib import Path

class Deduper:
    """
    tools to start from an existing directory to make sure we don't have duplicates in template
    """
    def __init__(self, path: str):
        self.fileobj_path = Path(path).expanduser().resolve()
        self.fileobj_path.mkdir(parents=True, exist_ok=True)
        
        self.hash_dict : Dict[str,str] = {}   #key is hash, file is name of file in dedupe          
            
        # load all the existing files
        for root, _, files in os.walk(self.fileobj_path):            
            for file in files:
                file_path = os.path.join(root, file)
                relative_path = os.path.relpath(file_path, self.fileobj_path)                
                print(f" - load deduped file {file_path}")
                if not file.startswith('.'):
                    file_hash = self._calculate_md5(file_path)
                    if file_hash in self.hash_dict:
                        raise Exception(f"duplicate in dedupe pool: {file_path}")
                    self.hash_dict[file_hash] = relative_path

    def _calculate_md5(self, file_path: str) -> str:
        hash_md5 = hashlib.md5()
        with open(file_path, "rb") as f:
            for chunk in iter(lambda: f.read(4096), b""):
                hash_md5.update(chunk)
        return hash_md5.hexdigest()

    # def find_or_add_file(self, file_path: str) -> str:
        
    #     file_hash = self._calculate_md5(file_path)

    #     if file_hash in self.hash_dict:
    #         print(f" - add file to dedupe: {file_path} existed")
    #         return self.hash_dict[file_hash]
            
    #     self.hash_dict[file_hash] = 
            
    #     print(f" - add file to dedupe: {file_path} new")

    #     return file_path
    
    
    #check filename exists in pool (case insensitive) if yes return the filelocation in the dedupe pool
    def check_from_name(self, file_name: str) -> str:
        for hash_val, stored_file_name in self.hash_dict.items():
            if stored_file_name.lower() == file_name.lower():
                return stored_file_name
        return ""
    
    #will check if file exists in dedupe pool
    def check_from_path(self, file_path: str) -> str:
        # Check if the file path exists
        if not Path(file_path).exists():
            raise FileNotFoundError(f"File '{file_path}' does not exist.")

        # Calculate the hash of the file
        file_hash = self._calculate_md5(file_path)

        # Check if the file exists in self.hash_dict
        if file_hash in self.hash_dict:
            stored_file_name = self.hash_dict[file_hash]
            return stored_file_name
            # Return the path relative to self.fileobj_path
            # return str(Path(stored_file_name).relative_to(self.fileobj_path))

        # If the file doesn't exist in self.hash_dict, return an empty string
        return ""    
    
    #return full path based on filename
    def full_path(self, file_name: str) -> str:
        return f"{self.fileobj_path}/{file_name}"