#!/usr/bin/env python3
"""
MCP server pro MongoDB — používá FastMCP.
Spustit: python mcp_mongo.py
"""

import json
import sys
import traceback
from datetime import datetime, date
from typing import Optional

from bson import ObjectId
from mcp.server.fastmcp import FastMCP
from pymongo import MongoClient

MONGO_HOST = "192.168.1.76"


def log(msg: str):
    print(msg, file=sys.stderr, flush=True)


try:
    client = MongoClient(MONGO_HOST, serverSelectionTimeoutMS=5000)
    client.server_info()
    log(f"Connected to MongoDB ({MONGO_HOST})")
except Exception as e:
    log(f"MongoDB connection failed: {e}")
    sys.exit(1)


def serialize(obj):
    """Make MongoDB documents JSON-serializable."""
    if isinstance(obj, ObjectId):
        return str(obj)
    if isinstance(obj, datetime):
        return obj.isoformat()
    if isinstance(obj, date):
        return obj.isoformat()
    if isinstance(obj, bytes):
        return obj.decode("utf-8", errors="replace")
    if isinstance(obj, dict):
        return {k: serialize(v) for k, v in obj.items()}
    if isinstance(obj, list):
        return [serialize(v) for v in obj]
    return obj


def parse_filter(filter_json: Optional[str]) -> dict:
    """Parse JSON string to dict. Returns {} on None/empty."""
    if not filter_json or not filter_json.strip():
        return {}
    return json.loads(filter_json)


mcp = FastMCP("janssen-mongo")


@mcp.tool()
def list_databases() -> dict:
    """List all databases on the MongoDB server (excludes admin/config/local)."""
    try:
        skip = {"admin", "config", "local"}
        dbs = [d["name"] for d in client.list_databases() if d["name"] not in skip]
        return {"count": len(dbs), "databases": dbs}
    except Exception:
        log(f"list_databases error: {traceback.format_exc()}")
        raise


@mcp.tool()
def list_collections(db: str) -> dict:
    """List all collections in a database."""
    try:
        cols = sorted(client[db].list_collection_names())
        return {"db": db, "count": len(cols), "collections": cols}
    except Exception:
        log(f"list_collections error: {traceback.format_exc()}")
        raise


@mcp.tool()
def collection_stats(db: str, collection: str) -> dict:
    """Returns document count + schema sample (fields and types from first document)."""
    try:
        col = client[db][collection]
        count = col.estimated_document_count()
        sample = col.find_one()
        schema = {}
        if sample:
            for k, v in sample.items():
                schema[k] = type(v).__name__
        return {"db": db, "collection": collection, "count": count, "schema": schema}
    except Exception:
        log(f"collection_stats error: {traceback.format_exc()}")
        raise


@mcp.tool()
def find_documents(
    db: str,
    collection: str,
    filter_json: Optional[str] = None,
    projection_json: Optional[str] = None,
    sort_json: Optional[str] = None,
    limit: int = 50,
) -> dict:
    """Query documents. filter/projection/sort are JSON strings, e.g. '{"patient_code":"CZ1-01"}'.
    sort example: '{"last_seen_at": -1}'. Limit max 500.
    """
    try:
        col = client[db][collection]
        filt = parse_filter(filter_json)
        proj = parse_filter(projection_json) or None
        sort_spec = parse_filter(sort_json)
        limit = min(limit, 500)

        cursor = col.find(filt, proj)
        if sort_spec:
            cursor = cursor.sort(list(sort_spec.items()))
        cursor = cursor.limit(limit)

        docs = [serialize(doc) for doc in cursor]
        return {"count": len(docs), "docs": docs}
    except Exception:
        log(f"find_documents error: {traceback.format_exc()}")
        raise


@mcp.tool()
def aggregate(db: str, collection: str, pipeline_json: str) -> dict:
    """Run a MongoDB aggregation pipeline. pipeline_json is a JSON array of stages,
    e.g. '[{"$group": {"_id": "$patient_code", "count": {"$sum": 1}}}]'.
    """
    try:
        col = client[db][collection]
        pipeline = json.loads(pipeline_json)
        results = [serialize(doc) for doc in col.aggregate(pipeline)]
        return {"count": len(results), "results": results}
    except Exception:
        log(f"aggregate error: {traceback.format_exc()}")
        raise


@mcp.tool()
def distinct_values(db: str, collection: str, field: str, filter_json: Optional[str] = None) -> dict:
    """Return distinct values of a field, optionally filtered."""
    try:
        col = client[db][collection]
        filt = parse_filter(filter_json)
        values = [serialize(v) for v in col.distinct(field, filt)]
        return {"field": field, "count": len(values), "values": values}
    except Exception:
        log(f"distinct_values error: {traceback.format_exc()}")
        raise


if __name__ == "__main__":
    log("MCP MongoDB server started (FastMCP)")
    mcp.run()