"""MCP server providing memory tools with namespace support.

This server uses FastMCP and stores data in a JSON file (data.json).
The JSON structure is a dictionary mapping keys to objects containing value and timestamp.
"""

import json
import time
from pathlib import Path

from fastmcp import mcp
from pydantic import BaseModel
from dotenv import load_dotenv

# Load environment variables if .env exists
load_dotenv()

DATA_FILE = Path("data.json")

# Ensure data file exists
if not DATA_FILE.exists():
    DATA_FILE.write_text("{}")

class DataEntry(BaseModel):
    value: str
    timestamp: float

# Helper functions for file operations

def _load_data() -> dict:
    try:
        text = DATA_FILE.read_text()
        return json.loads(text) if text else {}
    except json.JSONDecodeError:
        return {}

def _save_data(data: dict) -> None:
    DATA_FILE.write_text(json.dumps(data, indent=2))

# Tool implementations

@mcp.tool()
def save(key: str, value: str) -> str:
    data = _load_data()
    data[key] = DataEntry(value=value, timestamp=time.time()).dict()
    _save_data(data)
    return f"Saved key '{key}'."

@mcp.tool()
def get(key: str) -> str:
    data = _load_data()
    entry = data.get(key)
    if not entry:
        return f"Key '{key}' not found."
    return entry["value"]

@mcp.tool()
def delete(key: str) -> str:
    data = _load_data()
    if key in data:
        del data[key]
        _save_data(data)
        return f"Deleted key '{key}'."
    return f"Key '{key}' not found."

@mcp.tool()
def list_keys() -> str:
    data = _load_data()
    return json.dumps(list(data.keys()))

# Namespace tools

@mcp.tool()
def save_with_namespace(namespace: str, key: str, value: str) -> str:
    namespaced_key = f"{namespace}:{key}"
    return save(namespaced_key, value)

@mcp.tool()
def get_by_namespace(namespace: str, key: str) -> str:
    namespaced_key = f"{namespace}:{key}"
    return get(namespaced_key)

# Main entrypoint
if __name__ == "__main__":
    mcp.run()