"""
LightRAG FastAPI Server
"""

from fastapi import FastAPI, Depends, HTTPException, status
import asyncio
import os
import logging
import logging.config
import uvicorn
import pipmaster as pm
from fastapi.staticfiles import StaticFiles
from fastapi.responses import RedirectResponse
from pathlib import Path
import configparser
from ascii_colors import ASCIIColors
from fastapi.middleware.cors import CORSMiddleware
from contextlib import asynccontextmanager
from dotenv import load_dotenv
from lightrag.api.utils_api import (
    get_combined_auth_dependency,
    display_splash_screen,
    check_env_file,
)
from .config import (
    global_args,
    update_uvicorn_mode_config,
    get_default_host,
)
from lightrag.utils import get_env_value
import sys
from lightrag import LightRAG, __version__ as core_version
from lightrag.api import __api_version__
from lightrag.types import GPTKeywordExtractionFormat
from lightrag.utils import EmbeddingFunc
from lightrag.constants import (
    DEFAULT_LOG_MAX_BYTES,
    DEFAULT_LOG_BACKUP_COUNT,
    DEFAULT_LOG_FILENAME,
)
from lightrag.api.routers.document_routes import (
    DocumentManager,
    create_document_routes,
    run_scanning_process,
)
from lightrag.api.routers.query_routes import create_query_routes
from lightrag.api.routers.graph_routes import create_graph_routes
from lightrag.api.routers.ollama_api import OllamaAPI

from lightrag.utils import logger, set_verbose_debug
from lightrag.kg.shared_storage import (
    get_namespace_data,
    get_pipeline_status_lock,
    initialize_pipeline_status,
)
from fastapi.security import OAuth2PasswordRequestForm
from lightrag.api.auth import auth_handler

# use the .env that is inside the current folder
# allows to use different .env file for each lightrag instance
# the OS environment variables take precedence over the .env file
load_dotenv(dotenv_path=".env", override=False)


webui_title = os.getenv("WEBUI_TITLE")
webui_description = os.getenv("WEBUI_DESCRIPTION")

# Initialize config parser
config = configparser.ConfigParser()
config.read("config.ini")

# Global authentication configuration
auth_configured = bool(auth_handler.accounts)


def create_app(args):
    # Setup logging
    logger.setLevel(args.log_level)
    set_verbose_debug(args.verbose)

    # Verify that bindings are correctly setup
    if args.llm_binding not in [
        "lollms",
        "ollama",
        "openai",
        "openai-ollama",
        "azure_openai",
    ]:
        raise Exception("llm binding not supported")

    if args.embedding_binding not in ["lollms", "ollama", "openai", "azure_openai"]:
        raise Exception("embedding binding not supported")

    # Set default hosts if not provided
    if args.llm_binding_host is None:
        args.llm_binding_host = get_default_host(args.llm_binding)

    if args.embedding_binding_host is None:
        args.embedding_binding_host = get_default_host(args.embedding_binding)

    # Add SSL validation
    if args.ssl:
        if not args.ssl_certfile or not args.ssl_keyfile:
            raise Exception(
                "SSL certificate and key files must be provided when SSL is enabled"
            )
        if not os.path.exists(args.ssl_certfile):
            raise Exception(f"SSL certificate file not found: {args.ssl_certfile}")
        if not os.path.exists(args.ssl_keyfile):
            raise Exception(f"SSL key file not found: {args.ssl_keyfile}")

    # Check if API key is provided either through env var or args
    api_key = os.getenv("LIGHTRAG_API_KEY") or args.key

    # Initialize document manager
    doc_manager = DocumentManager(args.input_dir)

    @asynccontextmanager
    async def lifespan(app: FastAPI):
        """Lifespan context manager for startup and shutdown events"""
        # Store background tasks
        app.state.background_tasks = set()

        try:
            # Initialize database connections
            await rag.initialize_storages()

            await initialize_pipeline_status()
            pipeline_status = await get_namespace_data("pipeline_status")

            should_start_autoscan = False
            async with get_pipeline_status_lock():
                # Auto scan documents if enabled
                if args.auto_scan_at_startup:
                    if not pipeline_status.get("autoscanned", False):
                        pipeline_status["autoscanned"] = True
                        should_start_autoscan = True

            # Only run auto scan when no other process started it first
            if should_start_autoscan:
                # Create background task
                task = asyncio.create_task(run_scanning_process(rag, doc_manager))
                app.state.background_tasks.add(task)
                task.add_done_callback(app.state.background_tasks.discard)
                logger.info(f"Process {os.getpid()} auto scan task started at startup.")

            ASCIIColors.green("\nServer is ready to accept connections! 🚀\n")

            yield

        finally:
            # Clean up database connections
            await rag.finalize_storages()

    # Initialize FastAPI
    app_kwargs = {
        "title": "LightRAG Server API",
        "description": "Providing API for LightRAG core, Web UI and Ollama Model Emulation"
        + "(With authentication)"
        if api_key
        else "",
        "version": __api_version__,
        "openapi_url": "/openapi.json",  # Explicitly set OpenAPI schema URL
        "docs_url": "/docs",  # Explicitly set docs URL
        "redoc_url": "/redoc",  # Explicitly set redoc URL
        "lifespan": lifespan,
    }

    # Configure Swagger UI parameters
    # Enable persistAuthorization and tryItOutEnabled for better user experience
    app_kwargs["swagger_ui_parameters"] = {
        "persistAuthorization": True,
        "tryItOutEnabled": True,
    }

    app = FastAPI(**app_kwargs)

    def get_cors_origins():
        """Get allowed origins from global_args
        Returns a list of allowed origins, defaults to ["*"] if not set
        """
        origins_str = global_args.cors_origins
        if origins_str == "*":
            return ["*"]
        return [origin.strip() for origin in origins_str.split(",")]

    # Add CORS middleware
    app.add_middleware(
        CORSMiddleware,
        allow_origins=get_cors_origins(),
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )

    # Create combined auth dependency for all endpoints
    combined_auth = get_combined_auth_dependency(api_key)

    # Create working directory if it doesn't exist
    Path(args.working_dir).mkdir(parents=True, exist_ok=True)
    if args.llm_binding == "lollms" or args.embedding_binding == "lollms":
        from lightrag.llm.lollms import lollms_model_complete, lollms_embed
    if args.llm_binding == "ollama" or args.embedding_binding == "ollama":
        from lightrag.llm.ollama import ollama_model_complete, ollama_embed
    if args.llm_binding == "openai" or args.embedding_binding == "openai":
        from lightrag.llm.openai import openai_complete_if_cache, openai_embed
    if args.llm_binding == "azure_openai" or args.embedding_binding == "azure_openai":
        from lightrag.llm.azure_openai import (
            azure_openai_complete_if_cache,
            azure_openai_embed,
        )
    if args.llm_binding_host == "openai-ollama" or args.embedding_binding == "ollama":
        from lightrag.llm.openai import openai_complete_if_cache
        from lightrag.llm.ollama import ollama_embed

    async def openai_alike_model_complete(
        prompt,
        system_prompt=None,
        history_messages=None,
        keyword_extraction=False,
        **kwargs,
    ) -> str:
        keyword_extraction = kwargs.pop("keyword_extraction", None)
        if keyword_extraction:
            kwargs["response_format"] = GPTKeywordExtractionFormat
        if history_messages is None:
            history_messages = []
        kwargs["temperature"] = args.temperature
        return await openai_complete_if_cache(
            args.llm_model,
            prompt,
            system_prompt=system_prompt,
            history_messages=history_messages,
            base_url=args.llm_binding_host,
            api_key=args.llm_binding_api_key,
            **kwargs,
        )

    async def azure_openai_model_complete(
        prompt,
        system_prompt=None,
        history_messages=None,
        keyword_extraction=False,
        **kwargs,
    ) -> str:
        keyword_extraction = kwargs.pop("keyword_extraction", None)
        if keyword_extraction:
            kwargs["response_format"] = GPTKeywordExtractionFormat
        if history_messages is None:
            history_messages = []
        kwargs["temperature"] = args.temperature
        return await azure_openai_complete_if_cache(
            args.llm_model,
            prompt,
            system_prompt=system_prompt,
            history_messages=history_messages,
            base_url=args.llm_binding_host,
            api_key=os.getenv("AZURE_OPENAI_API_KEY"),
            api_version=os.getenv("AZURE_OPENAI_API_VERSION", "2024-08-01-preview"),
            **kwargs,
        )

    embedding_func = EmbeddingFunc(
        embedding_dim=args.embedding_dim,
        max_token_size=args.max_embed_tokens,
        func=lambda texts: lollms_embed(
            texts,
            embed_model=args.embedding_model,
            host=args.embedding_binding_host,
            api_key=args.embedding_binding_api_key,
        )
        if args.embedding_binding == "lollms"
        else ollama_embed(
            texts,
            embed_model=args.embedding_model,
            host=args.embedding_binding_host,
            api_key=args.embedding_binding_api_key,
        )
        if args.embedding_binding == "ollama"
        else azure_openai_embed(
            texts,
            model=args.embedding_model,  # no host is used for openai,
            api_key=args.embedding_binding_api_key,
        )
        if args.embedding_binding == "azure_openai"
        else openai_embed(
            texts,
            model=args.embedding_model,
            base_url=args.embedding_binding_host,
            api_key=args.embedding_binding_api_key,
        ),
    )

    # Initialize RAG
    if args.llm_binding in ["lollms", "ollama", "openai"]:
        rag = LightRAG(
            working_dir=args.working_dir,
            llm_model_func=lollms_model_complete
            if args.llm_binding == "lollms"
            else ollama_model_complete
            if args.llm_binding == "ollama"
            else openai_alike_model_complete,
            llm_model_name=args.llm_model,
            llm_model_max_async=args.max_async,
            llm_model_max_token_size=args.max_tokens,
            chunk_token_size=int(args.chunk_size),
            chunk_overlap_token_size=int(args.chunk_overlap_size),
            llm_model_kwargs={
                "host": args.llm_binding_host,
                "timeout": args.timeout,
                "options": {"num_ctx": args.max_tokens},
                "api_key": args.llm_binding_api_key,
            }
            if args.llm_binding == "lollms" or args.llm_binding == "ollama"
            else {},
            embedding_func=embedding_func,
            kv_storage=args.kv_storage,
            graph_storage=args.graph_storage,
            vector_storage=args.vector_storage,
            doc_status_storage=args.doc_status_storage,
            vector_db_storage_cls_kwargs={
                "cosine_better_than_threshold": args.cosine_threshold
            },
            enable_llm_cache_for_entity_extract=args.enable_llm_cache_for_extract,
            enable_llm_cache=args.enable_llm_cache,
            auto_manage_storages_states=False,
            max_parallel_insert=args.max_parallel_insert,
            addon_params={"language": args.summary_language},
        )
    else:  # azure_openai
        rag = LightRAG(
            working_dir=args.working_dir,
            llm_model_func=azure_openai_model_complete,
            chunk_token_size=int(args.chunk_size),
            chunk_overlap_token_size=int(args.chunk_overlap_size),
            llm_model_kwargs={
                "timeout": args.timeout,
            },
            llm_model_name=args.llm_model,
            llm_model_max_async=args.max_async,
            llm_model_max_token_size=args.max_tokens,
            embedding_func=embedding_func,
            kv_storage=args.kv_storage,
            graph_storage=args.graph_storage,
            vector_storage=args.vector_storage,
            doc_status_storage=args.doc_status_storage,
            vector_db_storage_cls_kwargs={
                "cosine_better_than_threshold": args.cosine_threshold
            },
            enable_llm_cache_for_entity_extract=args.enable_llm_cache_for_extract,
            enable_llm_cache=args.enable_llm_cache,
            auto_manage_storages_states=False,
            max_parallel_insert=args.max_parallel_insert,
            addon_params={"language": args.summary_language},
        )

    # Add routes
    app.include_router(create_document_routes(rag, doc_manager, api_key))
    app.include_router(create_query_routes(rag, api_key, args.top_k))
    app.include_router(create_graph_routes(rag, api_key))

    # Add Ollama API routes
    ollama_api = OllamaAPI(rag, top_k=args.top_k, api_key=api_key)
    app.include_router(ollama_api.router, prefix="/api")

    @app.get("/")
    async def redirect_to_webui():
        """Redirect root path to /webui"""
        return RedirectResponse(url="/webui")

    @app.get("/auth-status")
    async def get_auth_status():
        """Get authentication status and guest token if auth is not configured"""

        if not auth_handler.accounts:
            # Authentication not configured, return guest token
            guest_token = auth_handler.create_token(
                username="guest", role="guest", metadata={"auth_mode": "disabled"}
            )
            return {
                "auth_configured": False,
                "access_token": guest_token,
                "token_type": "bearer",
                "auth_mode": "disabled",
                "message": "Authentication is disabled. Using guest access.",
                "core_version": core_version,
                "api_version": __api_version__,
                "webui_title": webui_title,
                "webui_description": webui_description,
            }

        return {
            "auth_configured": True,
            "auth_mode": "enabled",
            "core_version": core_version,
            "api_version": __api_version__,
            "webui_title": webui_title,
            "webui_description": webui_description,
        }

    @app.post("/login")
    async def login(form_data: OAuth2PasswordRequestForm = Depends()):
        if not auth_handler.accounts:
            # Authentication not configured, return guest token
            guest_token = auth_handler.create_token(
                username="guest", role="guest", metadata={"auth_mode": "disabled"}
            )
            return {
                "access_token": guest_token,
                "token_type": "bearer",
                "auth_mode": "disabled",
                "message": "Authentication is disabled. Using guest access.",
                "core_version": core_version,
                "api_version": __api_version__,
                "webui_title": webui_title,
                "webui_description": webui_description,
            }
        username = form_data.username
        if auth_handler.accounts.get(username) != form_data.password:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED, detail="Incorrect credentials"
            )

        # Regular user login
        user_token = auth_handler.create_token(
            username=username, role="user", metadata={"auth_mode": "enabled"}
        )
        return {
            "access_token": user_token,
            "token_type": "bearer",
            "auth_mode": "enabled",
            "core_version": core_version,
            "api_version": __api_version__,
            "webui_title": webui_title,
            "webui_description": webui_description,
        }

    @app.get("/health", dependencies=[Depends(combined_auth)])
    async def get_status():
        """Get current system status"""
        try:
            pipeline_status = await get_namespace_data("pipeline_status")

            if not auth_configured:
                auth_mode = "disabled"
            else:
                auth_mode = "enabled"

            return {
                "status": "healthy",
                "working_directory": str(args.working_dir),
                "input_directory": str(args.input_dir),
                "configuration": {
                    # LLM configuration binding/host address (if applicable)/model (if applicable)
                    "llm_binding": args.llm_binding,
                    "llm_binding_host": args.llm_binding_host,
                    "llm_model": args.llm_model,
                    # embedding model configuration binding/host address (if applicable)/model (if applicable)
                    "embedding_binding": args.embedding_binding,
                    "embedding_binding_host": args.embedding_binding_host,
                    "embedding_model": args.embedding_model,
                    "max_tokens": args.max_tokens,
                    "kv_storage": args.kv_storage,
                    "doc_status_storage": args.doc_status_storage,
                    "graph_storage": args.graph_storage,
                    "vector_storage": args.vector_storage,
                    "enable_llm_cache_for_extract": args.enable_llm_cache_for_extract,
                    "enable_llm_cache": args.enable_llm_cache,
                },
                "auth_mode": auth_mode,
                "pipeline_busy": pipeline_status.get("busy", False),
                "core_version": core_version,
                "api_version": __api_version__,
                "webui_title": webui_title,
                "webui_description": webui_description,
            }
        except Exception as e:
            logger.error(f"Error getting health status: {str(e)}")
            raise HTTPException(status_code=500, detail=str(e))

    # Custom StaticFiles class to prevent caching of HTML files
    class NoCacheStaticFiles(StaticFiles):
        async def get_response(self, path: str, scope):
            response = await super().get_response(path, scope)
            if path.endswith(".html"):
                response.headers["Cache-Control"] = (
                    "no-cache, no-store, must-revalidate"
                )
                response.headers["Pragma"] = "no-cache"
                response.headers["Expires"] = "0"
            return response

    # Webui mount webui/index.html
    static_dir = Path(__file__).parent / "webui"
    static_dir.mkdir(exist_ok=True)
    app.mount(
        "/webui",
        NoCacheStaticFiles(directory=static_dir, html=True, check_dir=True),
        name="webui",
    )

    return app


def get_application(args=None):
    """Factory function for creating the FastAPI application"""
    if args is None:
        args = global_args
    return create_app(args)


def configure_logging():
    """Configure logging for uvicorn startup"""

    # Reset any existing handlers to ensure clean configuration
    for logger_name in ["uvicorn", "uvicorn.access", "uvicorn.error", "lightrag"]:
        logger = logging.getLogger(logger_name)
        logger.handlers = []
        logger.filters = []

    # Get log directory path from environment variable
    log_dir = os.getenv("LOG_DIR", os.getcwd())
    log_file_path = os.path.abspath(os.path.join(log_dir, DEFAULT_LOG_FILENAME))

    print(f"\nLightRAG log file: {log_file_path}\n")
    os.makedirs(os.path.dirname(log_dir), exist_ok=True)

    # Get log file max size and backup count from environment variables
    log_max_bytes = get_env_value("LOG_MAX_BYTES", DEFAULT_LOG_MAX_BYTES, int)
    log_backup_count = get_env_value("LOG_BACKUP_COUNT", DEFAULT_LOG_BACKUP_COUNT, int)

    logging.config.dictConfig(
        {
            "version": 1,
            "disable_existing_loggers": False,
            "formatters": {
                "default": {
                    "format": "%(levelname)s: %(message)s",
                },
                "detailed": {
                    "format": "%(asctime)s - %(name)s - %(levelname)s - %(message)s",
                },
            },
            "handlers": {
                "console": {
                    "formatter": "default",
                    "class": "logging.StreamHandler",
                    "stream": "ext://sys.stderr",
                },
                "file": {
                    "formatter": "detailed",
                    "class": "logging.handlers.RotatingFileHandler",
                    "filename": log_file_path,
                    "maxBytes": log_max_bytes,
                    "backupCount": log_backup_count,
                    "encoding": "utf-8",
                },
            },
            "loggers": {
                # Configure all uvicorn related loggers
                "uvicorn": {
                    "handlers": ["console", "file"],
                    "level": "INFO",
                    "propagate": False,
                },
                "uvicorn.access": {
                    "handlers": ["console", "file"],
                    "level": "INFO",
                    "propagate": False,
                    "filters": ["path_filter"],
                },
                "uvicorn.error": {
                    "handlers": ["console", "file"],
                    "level": "INFO",
                    "propagate": False,
                },
                "lightrag": {
                    "handlers": ["console", "file"],
                    "level": "INFO",
                    "propagate": False,
                    "filters": ["path_filter"],
                },
            },
            "filters": {
                "path_filter": {
                    "()": "lightrag.utils.LightragPathFilter",
                },
            },
        }
    )


def check_and_install_dependencies():
    """Check and install required dependencies"""
    required_packages = [
        "uvicorn",
        "tiktoken",
        "fastapi",
        # Add other required packages here
    ]

    for package in required_packages:
        if not pm.is_installed(package):
            print(f"Installing {package}...")
            pm.install(package)
            print(f"{package} installed successfully")


def main():
    # Check if running under Gunicorn
    if "GUNICORN_CMD_ARGS" in os.environ:
        # If started with Gunicorn, return directly as Gunicorn will call get_application
        print("Running under Gunicorn - worker management handled by Gunicorn")
        return

    # Check .env file
    if not check_env_file():
        sys.exit(1)

    # Check and install dependencies
    check_and_install_dependencies()

    from multiprocessing import freeze_support

    freeze_support()

    # Configure logging before parsing args
    configure_logging()
    update_uvicorn_mode_config()
    display_splash_screen(global_args)

    # Create application instance directly instead of using factory function
    app = create_app(global_args)

    # Start Uvicorn in single process mode
    uvicorn_config = {
        "app": app,  # Pass application instance directly instead of string path
        "host": global_args.host,
        "port": global_args.port,
        "log_config": None,  # Disable default config
    }

    if global_args.ssl:
        uvicorn_config.update(
            {
                "ssl_certfile": global_args.ssl_certfile,
                "ssl_keyfile": global_args.ssl_keyfile,
            }
        )

    print(
        f"Starting Uvicorn server in single-process mode on {global_args.host}:{global_args.port}"
    )
    uvicorn.run(**uvicorn_config)


if __name__ == "__main__":
    main()
