import os
import shutil
from abc import ABC, abstractmethod
from typing import List

class NoteServer(ABC):
    @abstractmethod
    def list_notes(self, directory: str) -> List[str]:
        """List all markdown files in the directory."""
        pass

    @abstractmethod
    def read_note(self, file_path: str) -> str:
        """Read content of a note."""
        pass

    @abstractmethod
    def move_note(self, file_path: str, target_folder: str) -> str:
        """Move a note to a target folder."""
        pass

    @abstractmethod
    def flag_rewrite(self, file_path: str, reason: str, rewrite_tag: str) -> str:
        """Append a rewrite tag and reason to the note."""
        pass

    @abstractmethod
    def list_subfolders(self, directory: str) -> List[str]:
        """List immediate subdirectories."""
        pass

class FileSystemServer(NoteServer):
    def list_subfolders(self, directory: str) -> List[str]:
        if not os.path.exists(directory):
            return []
        try:
            return [d for d in os.listdir(directory) if os.path.isdir(os.path.join(directory, d)) and not d.startswith(".")]
        except Exception:
            return []

    def list_notes(self, directory: str) -> List[str]:
        notes = []
        if not os.path.exists(directory):
            return []
        for root, _, files in os.walk(directory):
            for file in files:
                if file.endswith(".md"):
                    # Only return absolute paths to keep things simple
                    notes.append(os.path.abspath(os.path.join(root, file)))
        return notes

    def read_note(self, file_path: str) -> str:
        try:
            with open(file_path, "r", encoding="utf-8") as f:
                return f.read()
        except Exception as e:
            return f"Error reading file: {str(e)}"

    def move_note(self, file_path: str, target_folder: str) -> str:
        try:
            filename = os.path.basename(file_path)
            
            # Ensure target folder exists
            if not os.path.exists(target_folder):
                os.makedirs(target_folder)
            
            new_path = os.path.join(target_folder, filename)
            
            # Prevent overwriting by appending timestamp if exists, or just fail safely
            if os.path.exists(new_path):
                return f"Error: File {filename} already exists in {target_folder}"

            shutil.move(file_path, new_path)
            return f"Moved {filename} to {target_folder}"
        except Exception as e:
            return f"Error moving file: {str(e)}"

    def flag_rewrite(self, file_path: str, reason: str, rewrite_tag: str) -> str:
        try:
            # Check if file ends with newline to avoid appending on same line
            with open(file_path, "r+", encoding="utf-8") as f:
                content = f.read()
                prefix = "\n" if content and not content.endswith("\n") else ""
                f.write(f"{prefix}\n{rewrite_tag} {reason}\n")
            return f"Flagged {os.path.basename(file_path)} for rewrite: {reason}"
        except Exception as e:
            return f"Error flagging file: {str(e)}"

from .couch_manager import CouchDBManager

class CouchDBNoteServer(NoteServer):
    def __init__(self, url, user, password, db_name):
        self.manager = CouchDBManager(url, user, password, db_name)

    def list_notes(self, directory: str) -> List[str]:
        # Directory here acts as a prefix filter
        files_dict = self.manager.list_files(prefix_filter=directory)
        return list(files_dict.keys())

    def list_subfolders(self, directory: str) -> List[str]:
        # CouchDB is flat. We simulate folders by looking at paths.
        # This is expensive (scan all), but accurate.
        all_files_dict = self.manager.list_files()
        subfolders = set()
        
        # If directory is "(All Notes)", we look at root folders
        # If directory is "Inbox", we look at "Inbox/Subfolder"
        
        prefix = directory if directory != "(All Notes)" else ""
        prefix = prefix.strip("/")
        
        for doc_id, path in all_files_dict.items():
            
            # Normalize path
            path = path.replace("\\", "/")
            
            if prefix and not path.startswith(prefix + "/"):
                continue
            
            # Strip prefix
            relative_path = path[len(prefix)+1:] if prefix else path
            
            if "/" in relative_path:
                top_level = relative_path.split("/")[0]
                subfolders.add(top_level)
                
        return sorted(list(subfolders))

    def read_note(self, file_path: str) -> str:
        return self.manager.read_file_content(file_path)

    def move_note(self, file_path: str, target_folder: str) -> str:
        return self.manager.move_file(file_path, target_folder)

    def flag_rewrite(self, file_path: str, reason: str, rewrite_tag: str) -> str:
        return self.manager.flag_rewrite(file_path, reason, rewrite_tag)