"""Excalidraw MCP Server Integration.

Manages the external excalidraw-mcp server process for hand-drawn style diagram generation.

Architecture:
    Garvis → (stdio) → excalidraw-mcp (Node.js) → Canvas API → PNG/SVG images
"""

import os
from pathlib import Path
from typing import Any, Dict, List
import yaml

_CONFIG_FILE = Path("config/excalidraw_mcp.yaml")

def _load_config() -> Dict[str, Any]:
    """Load Excalidraw MCP configuration from YAML and env vars."""
    config = {}
    if _CONFIG_FILE.exists():
        try:
            with open(_CONFIG_FILE, encoding="utf-8") as f:
                config = yaml.safe_load(f) or {}
        except Exception:
            pass  # Use defaults if config fails to load

    excalidraw = config.get("excalidraw_mcp", {})

    # Apply env var overrides
    if os.getenv("EXCALIDRAW_ENABLED"):
        excalidraw["enabled"] = os.getenv("EXCALIDRAW_ENABLED").lower() in ("true", "1")
    if os.getenv("EXCALIDRAW_OUTPUT_DIR"):
        excalidraw["output_dir"] = os.getenv("EXCALIDRAW_OUTPUT_DIR")
    if os.getenv("EXCALIDRAW_DEFAULT_EXPORT"):
        excalidraw["default_export_type"] = os.getenv("EXCALIDRAW_DEFAULT_EXPORT")

    # Set defaults if not configured
    excalidraw.setdefault("enabled", True)
    excalidraw.setdefault("output_dir", "downloads/diagrams/excalidraw")
    excalidraw.setdefault("default_export_type", "png")
    excalidraw.setdefault("canvas_width", 1920)
    excalidraw.setdefault("canvas_height", 1080)

    return excalidraw

def is_excalidraw_enabled() -> bool:
    """Check if Excalidraw MCP integration is enabled."""
    config = _load_config()
    return config.get("enabled", True)

def get_excalidraw_server_config() -> Dict[str, Any]:
    """Build the MCP server configuration for Agent SDK registration.

    Returns:
        Dict with command, args, and env for subprocess execution
    """
    config = _load_config()
    output_dir = config.get("output_dir", "downloads/diagrams/excalidraw")

    # Ensure output directory exists
    Path(output_dir).mkdir(parents=True, exist_ok=True)

    # Build environment variables for the MCP server
    env = {
        "PATH": os.environ.get("PATH", ""),
        "HOME": os.environ.get("HOME", os.environ.get("USERPROFILE", "")),
        "APPDATA": os.environ.get("APPDATA", ""),
        "TEMP": os.environ.get("TEMP", os.environ.get("TMP", "")),
    }

    # Add config as env vars for the server
    env["EXCALIDRAW_OUTPUT_DIR"] = str(Path(output_dir).absolute())
    env["EXCALIDRAW_DEFAULT_EXPORT"] = config.get("default_export_type", "png")
    env["EXCALIDRAW_CANVAS_WIDTH"] = str(config.get("canvas_width", 1920))
    env["EXCALIDRAW_CANVAS_HEIGHT"] = str(config.get("canvas_height", 1080))

    return {
        "command": "npx",
        "args": ["-y", "excalidraw-mcp"],
        "env": env,
    }

# Tool names exposed by excalidraw-mcp
# Based on excalidraw-mcp documentation
EXCALIDRAW_TOOLS: List[str] = [
    "create_diagram",      # Create new Excalidraw diagram
    "add_element",         # Add shape/element to diagram
    "export_diagram",      # Export to PNG/SVG
    "list_diagrams",       # List saved diagrams
]