"""File MCP tools - File operations with receipts."""

import json
import os
from datetime import datetime, timezone
from pathlib import Path
from typing import Any

import blake3

# VaultMesh root from env or default
VAULTMESH_ROOT = Path(os.environ.get("VAULTMESH_ROOT", Path(__file__).parents[3])).resolve()
RECEIPTS_ROOT = VAULTMESH_ROOT / "receipts"
FILE_RECEIPTS = RECEIPTS_ROOT / "file" / "file_operations.jsonl"


def _vmhash_blake3(data: bytes) -> str:
    """VaultMesh hash: blake3:<hex>."""
    return f"blake3:{blake3.blake3(data).hexdigest()}"


def _emit_file_receipt(operation: str, file_path: str, details: dict, actor: str = "did:vm:mcp:file") -> str:
    """Emit a receipt for file operation."""
    FILE_RECEIPTS.parent.mkdir(parents=True, exist_ok=True)

    body = {
        "operation": operation,
        "file_path": file_path,
        "details": details,
        "actor": actor,
    }

    root_hash = _vmhash_blake3(json.dumps(body, sort_keys=True).encode())

    receipt = {
        "schema_version": "2.0.0",
        "type": "file_operation",
        "timestamp": datetime.now(timezone.utc).isoformat(),
        "scroll": "file",
        "tags": ["file", operation, "mcp"],
        "root_hash": root_hash,
        "body": body,
    }

    with open(FILE_RECEIPTS, "a") as f:
        f.write(json.dumps(receipt) + "\n")

    return root_hash


def file_add(
    path: str,
    content: str,
    encoding: str = "utf-8",
    actor: str = "did:vm:mcp:file",
) -> dict[str, Any]:
    """
    Add (create or overwrite) a file with content.
    
    Args:
        path: File path relative to VAULTMESH_ROOT or absolute
        content: File content to write
        encoding: File encoding (default: utf-8)
        actor: DID of actor performing operation
    
    Returns:
        Result with file hash and receipt hash
    """
    try:
        file_path = Path(path)
        if not file_path.is_absolute():
            file_path = VAULTMESH_ROOT / file_path

        # Create parent directories if needed
        file_path.parent.mkdir(parents=True, exist_ok=True)

        # Write file
        file_path.write_text(content, encoding=encoding)

        # Hash the content
        content_hash = _vmhash_blake3(content.encode(encoding))

        details = {
            "content_hash": content_hash,
            "size_bytes": len(content.encode(encoding)),
            "encoding": encoding,
            "created": not file_path.exists(),
        }

        receipt_hash = _emit_file_receipt("add", str(file_path), details, actor)

        return {
            "success": True,
            "path": str(file_path),
            "content_hash": content_hash,
            "receipt_hash": receipt_hash,
            "size_bytes": details["size_bytes"],
        }

    except Exception as e:
        return {"success": False, "error": str(e)}