from fastapi import APIRouter
from fastapi.responses import HTMLResponse, FileResponse
from pathlib import Path
from typing import Dict, List

from core.registry.tasks_registry import TASKS


# =====================================================
# CONFIG
# =====================================================

BASE_DIR = Path(__file__).resolve().parents[2]
UI_DIR = BASE_DIR / "ui"
INDEX_FILE = UI_DIR / "index.html"


# =====================================================
# TASK GROUPING
# =====================================================

def group_tasks() -> Dict[str, List[dict]]:
    """
    Converts registry → categorized UI structure.
    """

    categories: Dict[str, List[dict]] = {}

    for task in TASKS:
        if not getattr(task, "enabled", True):
            continue

        category = getattr(task, "category", "general")

        categories.setdefault(category, []).append(
            {
                "name": task.name,
                "description": getattr(task, "description", ""),
            }
        )

    return categories


# =====================================================
# ROUTER BUILDER
# =====================================================

def build_ui_router() -> APIRouter:
    """
    Serves UI + dynamic UI metadata.

    Endpoints:
        /
        /ui
        /ui/tasks
        /ui/health
    """

    router = APIRouter(tags=["UI"])

    # -------------------------------------------------
    # MAIN UI
    # -------------------------------------------------
    @router.get("/", response_class=HTMLResponse)
    async def serve_root():
        """
        Serves index.html
        """

        if not INDEX_FILE.exists():
            return HTMLResponse(
                "<h1>Basyx UI Missing</h1>",
                status_code=500,
            )

        return FileResponse(INDEX_FILE)

    # -------------------------------------------------
    # Explicit UI route
    # -------------------------------------------------
    @router.get("/ui", response_class=HTMLResponse)
    async def serve_ui():
        return await serve_root()

    # -------------------------------------------------
    # UI TASK CATALOG
    # -------------------------------------------------
    @router.get("/ui/tasks")
    async def ui_tasks():
        """
        UI fetches this to build sidebar dynamically.
        """
        return group_tasks()

    # -------------------------------------------------
    # HEALTH
    # -------------------------------------------------
    @router.get("/ui/health")
    async def ui_health():
        return {
            "status": "ok",
            "ui": "active",
            "tasks": len(TASKS),
        }

    return router