from __future__ import annotations

import asyncio
from contextlib import asynccontextmanager

from fastapi import FastAPI, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.middleware.gzip import GZipMiddleware

from app.config import get_settings
from app.core.auth.deps import init_auth_db
from app.core.database import pool_manager
from app.core.logger import get_logger
from app.core.redis_client import create_redis_client, close_redis
from app.core.scripts import load_scripts
from app.core.vector_store.deps import init_vector_store_db
from app.services.embeddings_service import EmbeddingService
from app.services.vector_store_service import VectorStoreService
from app.api.v1.router import api_v1_router

_logger = get_logger(__name__)
_settings = get_settings()

_embedding_service: EmbeddingService = EmbeddingService()
_vector_store_service: VectorStoreService = VectorStoreService(_embedding_service)


async def _self_ping():
    import httpx
    health_url = _settings.self_ping_url
    while True:
        try:
            async with httpx.AsyncClient(timeout=30.0) as client:
                response = await client.get(health_url)
                if response.status_code == 200:
                    _logger.info("Self-ping successful: %s", health_url)
                else:
                    _logger.warning("Self-ping returned: %s - %s", health_url, response.status_code)
        except Exception as exc:
            _logger.error("Self-ping error: %s", exc)
        await asyncio.sleep(900)


@asynccontextmanager
async def lifespan(app: FastAPI):
    _logger.info("Initializing authentication database...")
    await init_auth_db()
    _logger.info("Authentication database initialized")

    _logger.info("Initializing vector store database...")
    await init_vector_store_db()
    await _vector_store_service.init_db()
    _logger.info("Vector store database initialized with %d stores", len(_vector_store_service.list_stores()))

    _logger.info("Initializing embedding service (loading 384-dim model)...")
    loop = asyncio.get_running_loop()
    await loop.run_in_executor(None, _embedding_service.load_model, 384)
    # await loop.run_in_executor(None, _embedding_service.load_vision_model)  # DISABLED (OOM mitigation)
    _logger.info("Embedding service initialized with dims: %s", _embedding_service.loaded_dimensions)
    _logger.info("Vector store service initialized with %d existing stores", len(_vector_store_service.list_stores()))

    redis = create_redis_client(_settings.redis_url) if _settings.redis_url else None
    scripts = await load_scripts(redis) if redis else {}
    app.state.redis = redis
    app.state.scripts = scripts
    if redis:
        _logger.info("Redis and Lua scripts initialized")
    else:
        _logger.warning("Redis not configured, running in degraded mode")

    asyncio.create_task(_self_ping())
    yield
    _logger.info("Shutting down...")
    await close_redis(redis)
    await _vector_store_service.close_all()
    await pool_manager.close_all()


def create_application() -> FastAPI:
    app = FastAPI(
        title=_settings.app_name,
        description="All API Collection",
        version=_settings.app_version,
        docs_url="/docs",
        redoc_url="/redoc",
        openapi_tags=[
            {"name": "Convert", "description": "Single-file and single-URL conversion"},
            {"name": "Batch", "description": "Bulk conversion of files and URLs"},
            {"name": "System", "description": "Health, info, and supported formats"},
            {"name": "Embeddings", "description": "Text embedding generation using transformer models"},
            {"name": "Verify", "description": "Phone number and identity verification"},
            {"name": "Vector Stores", "description": "Create, manage, and search vector stores for RAG"},
        ],
        lifespan=lifespan,
    )

    app.add_middleware(GZipMiddleware, minimum_size=1000)
    app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_methods=["*"],
        allow_headers=["*"],
    )

    app.include_router(api_v1_router, prefix="/api/v1")

    @app.get("/", include_in_schema=False)
    async def root(request: Request):
        from collections import defaultdict
        routes_by_tag: dict[str, list[dict]] = defaultdict(list)
        for route in app.routes:
            if not hasattr(route, "methods") or not hasattr(route, "path"):
                continue
            if route.path in ("/", "/health", "/ping", "/openapi.json", "/docs", "/redoc", "/docs/oauth2-redirect"):
                continue
            tags = getattr(route, "tags", None) or ["default"]
            for tag in tags:
                routes_by_tag[tag].append({
                    "method": list(route.methods - {"HEAD", "OPTIONS"}),
                    "path": route.path,
                    "summary": getattr(route, "summary", ""),
                })
        return {
            "name": _settings.app_name,
            "version": _settings.app_version,
            "docs": {
                "swagger": str(request.base_url) + "docs",
                "redoc": str(request.base_url) + "redoc",
            },
            "endpoints": [
                {"tag": tag, "routes": sorted(routes, key=lambda r: r["path"])}
                for tag, routes in sorted(routes_by_tag.items())
            ],
        }

    @app.get("/health", include_in_schema=False)
    async def root_health():
        store_count = len(_vector_store_service.list_stores())
        doc_count = await _vector_store_service.get_total_document_count()
        return {
            "success": True,
            "app_name": _settings.app_name,
            "version": _settings.app_version,
            "embedding_dimension": _settings.embedding_dimension,
            "vector_store_count": store_count,
            "total_documents": doc_count,
            "model_loaded": _embedding_service.is_loaded(384),
        }

    @app.get("/ping", include_in_schema=False)
    async def ping():
        return {"name": f"{_settings.app_name}", "version": _settings.app_version}

    return app


app = create_application()