"""
Velxio MCP Server

Exposes the following tools to MCP-compatible agents (e.g. Claude):

  - compile_project       Compile Arduino sketch files → hex / binary
  - run_project           Compile and return simulation-ready artifacts
  - import_wokwi_json     Parse a Wokwi diagram.json → Velxio circuit
  - export_wokwi_json     Serialise a Velxio circuit → Wokwi diagram.json
  - create_circuit        Create a new circuit definition
  - update_circuit        Merge changes into an existing circuit definition
  - generate_code_files   Generate starter Arduino code from a circuit

Transport:
  - stdio  — run `python mcp_server.py` for Claude Desktop / CLI agents
  - SSE    — mounted at /mcp in the FastAPI app for HTTP-based agents
"""

from __future__ import annotations

import json
import sys
from typing import Annotated, Any

from mcp.server.fastmcp import FastMCP

from app.mcp.wokwi import (
    format_wokwi_diagram,
    generate_arduino_sketch,
    parse_wokwi_diagram,
)
from app.services.arduino_cli import ArduinoCLIService

# ---------------------------------------------------------------------------
# Server setup
# ---------------------------------------------------------------------------

mcp = FastMCP(
    name="velxio",
    instructions=(
        "Velxio MCP server — create circuits, import/export Wokwi JSON, "
        "generate Arduino code, and compile projects."
    ),
)

_arduino = ArduinoCLIService()

# ---------------------------------------------------------------------------
# compile_project
# ---------------------------------------------------------------------------


@mcp.tool()
async def compile_project(
    files: Annotated[
        list[dict[str, str]],
        "List of source files. Each item must have 'name' (filename, e.g. 'sketch.ino') "
        "and 'content' (file text).",
    ],
    board: Annotated[
        str,
        "Arduino board FQBN, e.g. 'arduino:avr:uno' or 'rp2040:rp2040:rpipico'. "
        "Defaults to 'arduino:avr:uno'.",
    ] = "arduino:avr:uno",
) -> dict[str, Any]:
    """
    Compile one or more Arduino sketch files and return the compiled artifact.

    Returns a dict with:
      - success (bool)
      - hex_content (str | null)    Intel HEX for AVR boards
      - binary_content (str | null) Base-64 .bin/.uf2 for RP2040
      - binary_type (str | null)    'bin' or 'uf2'
      - stdout (str)
      - stderr (str)
      - error (str | null)
    """
    for f in files:
        if "name" not in f or "content" not in f:
            return {
                "success": False,
                "error": "Each file entry must have 'name' and 'content' keys.",
                "stdout": "",
                "stderr": "",
            }

    try:
        result = await _arduino.compile(files, board)
        return result
    except Exception as exc:  # pragma: no cover
        return {
            "success": False,
            "error": str(exc),
            "stdout": "",
            "stderr": "",
        }


# ---------------------------------------------------------------------------
# run_project
# ---------------------------------------------------------------------------


@mcp.tool()
async def run_project(
    files: Annotated[
        list[dict[str, str]],
        "List of source files (same format as compile_project).",
    ],
    board: Annotated[str, "Board FQBN (default: 'arduino:avr:uno')."] = "arduino:avr:uno",
) -> dict[str, Any]:
    """
    Compile the project and return simulation-ready artifacts.

    The Velxio frontend can load the returned hex_content / binary_content
    directly into its AVR / RP2040 emulator.  Actual execution happens
    client-side in the browser.

    Returns the same payload as compile_project plus a 'simulation_ready' flag.
    """
    result = await compile_project(files=files, board=board)
    result["simulation_ready"] = result.get("success", False)
    return result


# ---------------------------------------------------------------------------
# import_wokwi_json
# ---------------------------------------------------------------------------


@mcp.tool()
async def import_wokwi_json(
    diagram_json: Annotated[
        str,
        "Wokwi diagram.json content as a JSON string. "
        "Must contain at minimum a 'parts' array.",
    ],
) -> dict[str, Any]:
    """
    Parse a Wokwi diagram.json payload and return a Velxio circuit object.

    The returned circuit can be passed directly to export_wokwi_json,
    generate_code_files, compile_project, or saved as a Velxio project.

    Returns:
      - board_fqbn (str)         Detected Arduino board FQBN
      - components (list)        List of component objects
      - connections (list)       List of connection objects
      - version (int)
    """
    try:
        diagram = json.loads(diagram_json)
    except json.JSONDecodeError as exc:
        return {"error": f"Invalid JSON: {exc}"}

    if not isinstance(diagram, dict):
        return {"error": "diagram_json must be a JSON object."}

    return parse_wokwi_diagram(diagram)


# ---------------------------------------------------------------------------
# export_wokwi_json
# ---------------------------------------------------------------------------


@mcp.tool()
async def export_wokwi_json(
    circuit: Annotated[
        dict[str, Any],
        "Velxio circuit object with 'components', 'connections', and 'board_fqbn'.",
    ],
    author: Annotated[str, "Author name to embed in the diagram (default: 'velxio')."] = "velxio",
) -> dict[str, Any]:
    """
    Convert a Velxio circuit object into a Wokwi diagram.json payload.

    The returned payload is compatible with the Wokwi simulator and can be
    imported using the Wokwi zip import feature in Velxio.

    Returns the Wokwi diagram dict (version, author, editor, parts, connections).
    """
    if not isinstance(circuit, dict):
        return {"error": "circuit must be a JSON object."}

    return format_wokwi_diagram(circuit, author=author)


# ---------------------------------------------------------------------------
# create_circuit
# ---------------------------------------------------------------------------


@mcp.tool()
async def create_circuit(
    board_fqbn: Annotated[
        str,
        "Arduino board FQBN. e.g. 'arduino:avr:uno', 'rp2040:rp2040:rpipico'.",
    ] = "arduino:avr:uno",
    components: Annotated[
        list[dict[str, Any]] | None,
        "List of component objects. Each item may have: "
        "id (str), type (str, Wokwi element type), left (number), top (number), "
        "rotate (number), attrs (object).",
    ] = None,
    connections: Annotated[
        list[dict[str, Any]] | None,
        "List of connection objects. Each item may have: "
        "from_part (str), from_pin (str), to_part (str), to_pin (str), color (str).",
    ] = None,
) -> dict[str, Any]:
    """
    Create a new Velxio circuit definition.

    Example component types: wokwi-led, wokwi-pushbutton, wokwi-resistor,
    wokwi-buzzer, wokwi-servo, wokwi-lcd1602.

    Example connection:
      { "from_part": "uno", "from_pin": "13", "to_part": "led1", "to_pin": "A",
        "color": "green" }

    Returns the new circuit object (board_fqbn, components, connections, version).
    """
    components_list = components if components is not None else []
    connections_list = connections if connections is not None else []

    # Normalise components
    normalised_components: list[dict[str, Any]] = []
    for i, comp in enumerate(components_list):
        normalised_components.append(
            {
                "id": comp.get("id", f"comp{i}"),
                "type": comp.get("type", ""),
                "left": float(comp.get("left", 0)),
                "top": float(comp.get("top", 0)),
                "rotate": int(comp.get("rotate", 0)),
                "attrs": dict(comp.get("attrs", {})),
            }
        )

    # Normalise connections
    normalised_connections: list[dict[str, Any]] = []
    for conn in connections_list:
        normalised_connections.append(
            {
                "from_part": conn.get("from_part", ""),
                "from_pin": conn.get("from_pin", ""),
                "to_part": conn.get("to_part", ""),
                "to_pin": conn.get("to_pin", ""),
                "color": conn.get("color", "green"),
            }
        )

    return {
        "board_fqbn": board_fqbn,
        "components": normalised_components,
        "connections": normalised_connections,
        "version": 1,
    }


# ---------------------------------------------------------------------------
# update_circuit
# ---------------------------------------------------------------------------


@mcp.tool()
async def update_circuit(
    circuit: Annotated[
        dict[str, Any],
        "Existing Velxio circuit object to update.",
    ],
    add_components: Annotated[
        list[dict[str, Any]] | None,
        "Components to add. Merged after existing components.",
    ] = None,
    remove_component_ids: Annotated[
        list[str] | None,
        "IDs of components to remove.",
    ] = None,
    add_connections: Annotated[
        list[dict[str, Any]] | None,
        "Connections to add.",
    ] = None,
    remove_connections: Annotated[
        list[dict[str, Any]] | None,
        "Connections to remove (matched by from_part+from_pin+to_part+to_pin).",
    ] = None,
    board_fqbn: Annotated[
        str | None,
        "If provided, replaces the circuit board_fqbn.",
    ] = None,
) -> dict[str, Any]:
    """
    Merge changes into an existing Velxio circuit definition.

    Supports adding/removing components and connections, and changing the board.

    Returns the updated circuit object.
    """
    if not isinstance(circuit, dict):
        return {"error": "circuit must be a JSON object."}

    import copy

    updated = copy.deepcopy(circuit)

    if board_fqbn is not None:
        updated["board_fqbn"] = board_fqbn

    # Remove components
    if remove_component_ids:
        remove_set = set(remove_component_ids)
        updated["components"] = [
            c for c in updated.get("components", []) if c.get("id") not in remove_set
        ]

    # Add components
    existing_ids = {c.get("id") for c in updated.get("components", [])}
    for i, comp in enumerate(add_components or []):
        comp_id = comp.get("id", f"comp_new_{i}")
        if comp_id in existing_ids:
            comp_id = f"{comp_id}_new"
        updated.setdefault("components", []).append(
            {
                "id": comp_id,
                "type": comp.get("type", ""),
                "left": float(comp.get("left", 0)),
                "top": float(comp.get("top", 0)),
                "rotate": int(comp.get("rotate", 0)),
                "attrs": dict(comp.get("attrs", {})),
            }
        )

    # Remove connections (exact match)
    if remove_connections:
        def _conn_key(c: dict[str, Any]) -> tuple[str, str, str, str]:
            return (
                c.get("from_part", ""),
                c.get("from_pin", ""),
                c.get("to_part", ""),
                c.get("to_pin", ""),
            )

        remove_keys = {_conn_key(c) for c in remove_connections}
        updated["connections"] = [
            c for c in updated.get("connections", []) if _conn_key(c) not in remove_keys
        ]

    # Add connections
    for conn in (add_connections or []):
        updated.setdefault("connections", []).append(
            {
                "from_part": conn.get("from_part", ""),
                "from_pin": conn.get("from_pin", ""),
                "to_part": conn.get("to_part", ""),
                "to_pin": conn.get("to_pin", ""),
                "color": conn.get("color", "green"),
            }
        )

    return updated


# ---------------------------------------------------------------------------
# generate_code_files
# ---------------------------------------------------------------------------


@mcp.tool()
async def generate_code_files(
    circuit: Annotated[
        dict[str, Any],
        "Velxio circuit object (from create_circuit or import_wokwi_json).",
    ],
    sketch_name: Annotated[
        str,
        "Base name for the generated sketch file (without extension).",
    ] = "sketch",
    extra_instructions: Annotated[
        str,
        "Optional extra instructions or comments to embed in the sketch.",
    ] = "",
) -> dict[str, Any]:
    """
    Generate starter Arduino code files for the given circuit.

    Returns:
      - files: list of { "name": str, "content": str } — ready for compile_project
      - board_fqbn: str — detected board FQBN
    """
    if not isinstance(circuit, dict):
        return {"error": "circuit must be a JSON object."}

    sketch_content = generate_arduino_sketch(circuit, sketch_name=sketch_name)

    if extra_instructions:
        header = f"// {extra_instructions}\n"
        sketch_content = header + sketch_content

    board_fqbn: str = circuit.get("board_fqbn", "arduino:avr:uno")

    return {
        "files": [{"name": f"{sketch_name}.ino", "content": sketch_content}],
        "board_fqbn": board_fqbn,
    }