"""
ROA2WEB Unified Backend - Single FastAPI Application
Consolidates Reports, Data Entry, and Telegram modules into one process
"""

# =============================================================================
# UTF-8 ENCODING FIX FOR WINDOWS CONSOLE
# Must be at the TOP, before any logging or print statements
# Fixes: 'charmap' codec can't encode character errors with Romanian diacritics
# =============================================================================
import sys
if sys.platform == 'win32':
    # Force UTF-8 encoding on Windows console
    # This prevents encoding errors when logging Romanian characters (ă, î, ș, ț)
    import io
    sys.stdout = io.TextIOWrapper(sys.stdout.buffer, encoding='utf-8', errors='replace')
    sys.stderr = io.TextIOWrapper(sys.stderr.buffer, encoding='utf-8', errors='replace')

import asyncio
import logging
import os
import sys
from datetime import datetime
from pathlib import Path
from contextlib import asynccontextmanager

from dotenv import load_dotenv
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware

# Load environment variables
load_dotenv()

# Add project root and shared modules to path
project_root = Path(__file__).parent.parent
sys.path.insert(0, str(project_root))  # Enable 'from backend.xxx import yyy'
sys.path.insert(0, str(project_root / "shared"))  # Enable 'from shared.xxx import yyy'

# Import configuration
from backend.config import settings

# Import shared infrastructure
from shared.database.oracle_pool import oracle_pool
from shared.auth.middleware import AuthenticationMiddleware
from shared.auth.routes import create_auth_router
from shared.routes.companies import create_companies_router
from shared.routes.calendar import create_calendar_router
from shared.routes.system import create_system_router

# Import module router factories
from backend.modules.reports.routers import create_reports_router
from backend.modules.data_entry.routers import create_data_entry_router
from backend.modules.telegram.routers import create_telegram_router

# Configure logging (level from env: DEBUG, INFO, WARNING, ERROR)
log_level = os.getenv('LOG_LEVEL', 'INFO').upper()
logging.basicConfig(
    level=getattr(logging, log_level, logging.INFO),
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
    datefmt='%H:%M:%S'
)
# Reduce noise from third-party libraries
logging.getLogger('httpcore').setLevel(logging.WARNING)
logging.getLogger('httpx').setLevel(logging.WARNING)
logging.getLogger('multipart').setLevel(logging.WARNING)
logging.getLogger('doctr').setLevel(logging.WARNING)
logging.getLogger('tensorflow').setLevel(logging.WARNING)
logging.getLogger('PIL').setLevel(logging.WARNING)
logger = logging.getLogger(__name__)

# Global variables for background tasks
telegram_bot_task = None
ocr_job_worker_running = False
cleanup_task_running = False
email_cache_running = False
ssh_tunnel_monitoring = False


# ============================================================================
# INITIALIZATION FUNCTIONS
# ============================================================================

async def init_oracle_pool():
    """Initialize Oracle connection pool (shared by all modules)."""
    logger.info("[ORACLE] Initializing connection pool...")

    # Get configured servers
    servers = settings.get_oracle_servers()

    if servers:
        # Multi-server mode: register all servers for lazy pool creation
        logger.info(f"[ORACLE] Registering {len(servers)} servers for lazy pool creation:")
        for srv in servers:
            oracle_pool.register_server(
                server_id=srv.id,
                host=srv.host,
                port=srv.port,
                user=srv.user,
                password=srv.password,
                sid=srv.sid,
                service_name=srv.service_name,
            )
            logger.info(f"[ORACLE]   - {srv.id}: {srv.name} @ {srv.host}:{srv.port}")

        # Mark as initialized (pools will be created lazily on first connection)
        await oracle_pool.initialize()
    else:
        # Legacy single-server mode: initialize with env vars
        logger.info("[ORACLE] Using legacy single-server configuration")
        await oracle_pool.initialize()

    logger.info("[ORACLE] ✅ Pool manager initialized successfully")


async def init_reports_cache():
    """Initialize Reports cache system."""
    logger.info("[REPORTS] Initializing cache system...")
    try:
        from backend.modules.reports.cache import init_cache, init_event_monitor, get_cache
        from backend.modules.reports.cache.config import CacheConfig

        cache_config = CacheConfig.from_env()
        await init_cache(cache_config)
        logger.info(f"[REPORTS] ✅ Cache initialized: type={cache_config.cache_type}, enabled={cache_config.enabled}")

        # Initialize event monitor
        cache = get_cache()
        await init_event_monitor(cache, cache_config)
        if cache_config.auto_invalidate_enabled:
            logger.info("[REPORTS] Event-based auto-invalidation ENABLED")
        else:
            logger.info("[REPORTS] Event-based auto-invalidation DISABLED")

    except Exception as e:
        logger.error(f"[REPORTS] ⚠️ Cache initialization error: {e}", exc_info=True)
        logger.warning("[REPORTS] Continuing without cache")


async def init_data_entry_db():
    """Initialize Data Entry SQLite database."""
    logger.info("[DATA-ENTRY] Initializing SQLite database...")
    try:
        from backend.modules.data_entry.db.database import init_db
        await init_db()
        logger.info(f"[DATA-ENTRY] ✅ Database initialized: {settings.data_entry_sqlite_database_path}")

        # Ensure upload directory exists
        settings.data_entry_upload_path_resolved
        logger.info(f"[DATA-ENTRY] Upload path: {settings.data_entry_upload_path_resolved}")

    except Exception as e:
        logger.error(f"[DATA-ENTRY] ❌ Database initialization error: {e}", exc_info=True)
        raise


async def init_telegram_db():
    """Initialize Telegram SQLite database."""
    logger.info("[TELEGRAM] Initializing SQLite database...")
    try:
        from backend.modules.telegram.db import init_database, cleanup_expired_codes, cleanup_expired_sessions, cleanup_expired_email_codes

        await init_database()
        logger.info(f"[TELEGRAM] ✅ Database initialized: {settings.telegram_sqlite_database_path}")

        # Cleanup expired data
        expired_codes = await cleanup_expired_codes()
        expired_sessions = await cleanup_expired_sessions()
        expired_email_codes = await cleanup_expired_email_codes()
        logger.info(f"[TELEGRAM] Cleanup: {expired_codes} codes, {expired_sessions} sessions, {expired_email_codes} email codes removed")

    except Exception as e:
        logger.error(f"[TELEGRAM] ❌ Database initialization error: {e}", exc_info=True)
        raise


async def init_ocr_job_worker():
    """Initialize OCR job worker with persistent PaddleOCR.

    This replaces the old background thread approach:
    - Starts ProcessPoolExecutor with persistent worker
    - Pre-warms PaddleOCR (loads once, reuses for all requests)
    - Starts job queue background task
    """
    global ocr_job_worker_running

    logger.info("[OCR] Initializing OCR job worker...")
    try:
        from backend.modules.data_entry.services.ocr.job_worker import start_job_worker, is_running

        success = await start_job_worker()
        ocr_job_worker_running = is_running()

        if success:
            logger.info("[OCR] ✅ Job worker started (PaddleOCR persistent)")
        else:
            logger.warning("[OCR] ⚠️ Job worker failed to start, falling back to sync mode")

    except Exception as e:
        logger.warning(f"[OCR] ⚠️ OCR job worker init failed: {e}")
        logger.warning("[OCR] Continuing with sync OCR mode")
        ocr_job_worker_running = False


async def init_cleanup_task():
    """Initialize the cleanup background task for expired failed receipts (US-008).

    Runs cleanup at startup and then every 24 hours:
    - Finds receipts with processing_status='failed' older than 7 days
    - Deletes the receipts and their attachment files from storage
    """
    global cleanup_task_running

    logger.info("[CLEANUP] Initializing cleanup background task...")
    try:
        from backend.modules.data_entry.services.cleanup_service import start_cleanup_task
        from backend.modules.data_entry.db.database import get_session

        success = await start_cleanup_task(get_session)
        cleanup_task_running = success

        if success:
            logger.info("[CLEANUP] ✅ Cleanup task started (runs daily)")
        else:
            logger.warning("[CLEANUP] ⚠️ Cleanup task failed to start")

    except Exception as e:
        logger.warning(f"[CLEANUP] ⚠️ Cleanup task init failed: {e}")
        cleanup_task_running = False


async def init_email_server_cache():
    """Initialize the email-server cache for multi-Oracle auto-discovery (US-003).

    Builds a cache mapping emails to server IDs by querying CONTAFIN_ORACLE.UTILIZATORI
    on each configured Oracle server. Starts auto-refresh every 15 minutes.
    """
    global email_cache_running

    # Only initialize if multi-server mode is configured
    servers = settings.get_oracle_servers()
    if not servers or len(servers) <= 1:
        logger.info("[EMAIL-CACHE] Single-server mode, skipping email cache initialization")
        return

    logger.info("[EMAIL-CACHE] Initializing email-server cache...")
    try:
        from shared.auth.email_server_cache import (
            email_server_cache,
            build_email_cache,
            start_email_cache_refresh
        )

        # Build initial cache
        await build_email_cache()

        # Start auto-refresh
        await start_email_cache_refresh()
        email_cache_running = True

        stats = email_server_cache.get_cache_stats()
        logger.info(f"[EMAIL-CACHE] ✅ Cache initialized: {stats['total_emails']} emails")

    except Exception as e:
        logger.warning(f"[EMAIL-CACHE] ⚠️ Cache init failed: {e}")
        logger.warning("[EMAIL-CACHE] Multi-server email lookup will not be available")
        email_cache_running = False


async def init_ssh_tunnel_monitoring():
    """Initialize SSH tunnel monitoring with auto-reconnect.

    This does NOT start tunnels - they should already be running
    (started by start.sh / start.ps1 / start-backend-service.ps1).

    Responsibilities:
    - Monitor tunnel health via port checks (every 30s)
    - Auto-restart tunnels if they go down
    - Expose status for /health endpoint
    """
    global ssh_tunnel_monitoring

    logger.info("[SSH-MONITOR] Initializing tunnel monitoring...")
    try:
        from backend.shared.ssh_tunnel_manager import ssh_tunnel_manager

        success = await ssh_tunnel_manager.start_monitoring()
        ssh_tunnel_monitoring = success

        if success:
            status = ssh_tunnel_manager.get_status()
            if status["status"] == "not_configured":
                logger.info("[SSH-MONITOR] No tunnels configured (direct connection mode)")
            else:
                logger.info(f"[SSH-MONITOR] ✅ Monitoring active: {status['status']}")
        else:
            logger.warning("[SSH-MONITOR] ⚠️ Failed to start monitoring")

    except Exception as e:
        logger.warning(f"[SSH-MONITOR] ⚠️ Init failed: {e}")
        ssh_tunnel_monitoring = False


async def run_telegram_bot():
    """Run Telegram bot as background task."""
    logger.info("[TELEGRAM] Starting bot...")
    try:
        from telegram.ext import Application, CommandHandler, CallbackQueryHandler, MessageHandler, filters
        from backend.modules.telegram.bot.handlers import (
            start_command, help_command, clear_command, companies_command,
            unlink_command, selectcompany_command, dashboard_command, sold_command,
            facturi_command, trezorerie_command, menu_command, trezorerie_casa_command,
            trezorerie_banca_command, clienti_command, furnizori_command, evolutie_command,
            clearcache_command, togglecache_command, handle_text_message, button_callback,
            error_handler
        )
        from backend.modules.telegram.bot.email_handlers import email_login_handler

        # Create Telegram application
        application = Application.builder().token(settings.telegram_bot_token).build()

        # Register handlers
        application.add_handler(email_login_handler)
        application.add_handler(CommandHandler("start", start_command))
        application.add_handler(CommandHandler("menu", menu_command))
        application.add_handler(CommandHandler("help", help_command))
        application.add_handler(CommandHandler("unlink", unlink_command))
        application.add_handler(CommandHandler("clear", clear_command))
        application.add_handler(CommandHandler("companies", companies_command))
        application.add_handler(CommandHandler("selectcompany", selectcompany_command))
        application.add_handler(CommandHandler("dashboard", dashboard_command))
        application.add_handler(CommandHandler("sold", sold_command))
        application.add_handler(CommandHandler("facturi", facturi_command))
        application.add_handler(CommandHandler("trezorerie", trezorerie_command))
        application.add_handler(CommandHandler("trezorerie_casa", trezorerie_casa_command))
        application.add_handler(CommandHandler("trezorerie_banca", trezorerie_banca_command))
        application.add_handler(CommandHandler("clienti", clienti_command))
        application.add_handler(CommandHandler("furnizori", furnizori_command))
        application.add_handler(CommandHandler("evolutie", evolutie_command))
        application.add_handler(CommandHandler("clearcache", clearcache_command))
        application.add_handler(CommandHandler("togglecache", togglecache_command))
        application.add_handler(MessageHandler(filters.TEXT & ~filters.COMMAND, handle_text_message))
        application.add_handler(CallbackQueryHandler(button_callback))
        application.add_error_handler(error_handler)

        # Initialize and start
        await application.initialize()
        await application.start()
        await application.updater.start_polling(
            drop_pending_updates=True,
            poll_interval=0,        # No delay between polls
            timeout=30              # Long poll timeout 30 seconds (reduces requests from ~6/min to ~2/min)
        )

        bot_info = await application.bot.get_me()
        logger.info(f"[TELEGRAM] ✅ Bot running: @{bot_info.username}")

        # Keep bot running
        while True:
            await asyncio.sleep(1)

    except asyncio.CancelledError:
        logger.info("[TELEGRAM] Bot task cancelled, stopping...")
        if 'application' in locals():
            await application.updater.stop()
            await application.stop()
            await application.shutdown()
        logger.info("[TELEGRAM] ✅ Bot stopped")
        raise
    except Exception as e:
        logger.error(f"[TELEGRAM] ❌ Bot error: {e}", exc_info=True)
        raise


# ============================================================================
# FASTAPI APPLICATION
# ============================================================================

app = FastAPI(
    title="ROA2WEB Unified Backend",
    description="Unified FastAPI backend for Reports, Data Entry, and Telegram modules",
    version="1.0.0"
)


# ============================================================================
# STARTUP/SHUTDOWN EVENT HANDLERS
# ============================================================================

@app.on_event("startup")
async def startup_event():
    """Application startup - Initialize all resources."""
    global telegram_bot_task

    logger.info("=" * 80)
    logger.info("[STARTUP] ROA2WEB Unified Backend")
    logger.info("=" * 80)

    try:
        # Step 1: Initialize Oracle pool (shared by all modules)
        await init_oracle_pool()

        # Step 2: Parallel initialization of module-specific resources
        logger.info("[STARTUP] Initializing module resources in parallel...")
        await asyncio.gather(
            init_reports_cache(),
            init_data_entry_db(),
            init_telegram_db(),
        )

        # Step 3: Initialize OCR job worker (with persistent PaddleOCR)
        await init_ocr_job_worker()

        # Step 4: Initialize cleanup task for expired failed receipts (US-008)
        await init_cleanup_task()

        # Step 5: Initialize email-server cache for multi-Oracle (US-003)
        await init_email_server_cache()

        # Step 6: Initialize SSH tunnel monitoring (auto-reconnect)
        await init_ssh_tunnel_monitoring()

        # Step 7: Start Telegram bot as background task
        if settings.telegram_bot_token:
            telegram_bot_task = asyncio.create_task(run_telegram_bot())
            logger.info("[STARTUP] ✅ Telegram bot task created")
        else:
            logger.warning("[STARTUP] ⚠️ TELEGRAM_BOT_TOKEN not set, bot disabled")

        logger.info("=" * 80)
        logger.info("[STARTUP] ✅ All modules initialized successfully")
        logger.info(f"[STARTUP] ✅ Server running on http://{settings.api_host}:{settings.api_port}")
        logger.info("=" * 80)

    except Exception as e:
        logger.error(f"[STARTUP] ❌ Initialization failed: {e}", exc_info=True)
        raise


@app.on_event("shutdown")
async def shutdown_event():
    """Application shutdown - Cleanup resources."""
    global telegram_bot_task, ocr_job_worker_running, cleanup_task_running, email_cache_running, ssh_tunnel_monitoring

    logger.info("=" * 80)
    logger.info("[SHUTDOWN] Stopping ROA2WEB Unified Backend...")
    logger.info("=" * 80)

    try:
        # Stop SSH tunnel monitoring
        if ssh_tunnel_monitoring:
            logger.info("[SHUTDOWN] Stopping SSH tunnel monitoring...")
            try:
                from backend.shared.ssh_tunnel_manager import ssh_tunnel_manager
                await ssh_tunnel_manager.stop_monitoring()
                ssh_tunnel_monitoring = False
                logger.info("[SHUTDOWN] SSH tunnel monitoring stopped")
            except Exception as e:
                logger.error(f"[SHUTDOWN] SSH tunnel monitoring error: {e}")

        # Stop email cache auto-refresh (US-003)
        if email_cache_running:
            logger.info("[SHUTDOWN] Stopping email cache auto-refresh...")
            try:
                from shared.auth.email_server_cache import stop_email_cache_refresh
                await stop_email_cache_refresh()
                email_cache_running = False
                logger.info("[SHUTDOWN] Email cache stopped")
            except Exception as e:
                logger.error(f"[SHUTDOWN] Email cache error: {e}")

        # Stop cleanup task (US-008)
        if cleanup_task_running:
            logger.info("[SHUTDOWN] Stopping cleanup task...")
            try:
                from backend.modules.data_entry.services.cleanup_service import stop_cleanup_task
                await stop_cleanup_task()
                cleanup_task_running = False
                logger.info("[SHUTDOWN] Cleanup task stopped")
            except Exception as e:
                logger.error(f"[SHUTDOWN] Cleanup task error: {e}")

        # Stop OCR job worker
        if ocr_job_worker_running:
            logger.info("[SHUTDOWN] Stopping OCR job worker...")
            try:
                from backend.modules.data_entry.services.ocr.job_worker import stop_job_worker
                await stop_job_worker()
                ocr_job_worker_running = False
                logger.info("[SHUTDOWN] OCR job worker stopped")
            except Exception as e:
                logger.error(f"[SHUTDOWN] OCR worker error: {e}")

        # Stop Telegram bot
        if telegram_bot_task and not telegram_bot_task.done():
            logger.info("[SHUTDOWN] Stopping Telegram bot...")
            telegram_bot_task.cancel()
            try:
                await telegram_bot_task
            except asyncio.CancelledError:
                pass

        # Stop Reports cache event monitor
        try:
            from backend.modules.reports.cache import close_cache, get_event_monitor
            monitor = get_event_monitor()
            if monitor:
                await monitor.stop()
                logger.info("[SHUTDOWN] Reports cache monitor stopped")

            await close_cache()
            logger.info("[SHUTDOWN] Reports cache closed")
        except Exception as e:
            logger.error(f"[SHUTDOWN] Cache error: {e}")

        # Close Oracle pool
        await oracle_pool.close_pool()
        logger.info("[SHUTDOWN] Oracle pool closed")

        logger.info("=" * 80)
        logger.info("[SHUTDOWN] ✅ Shutdown complete")
        logger.info("=" * 80)

    except Exception as e:
        logger.error(f"[SHUTDOWN] Error during shutdown: {e}", exc_info=True)


# ============================================================================
# MIDDLEWARE
# ============================================================================

# CORS middleware
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # Allow all origins for production deployment
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Authentication middleware
app.add_middleware(
    AuthenticationMiddleware,
    excluded_paths=[
        "/", "/docs", "/health", "/redoc", "/openapi.json",
        "/api/auth/login", "/api/auth/refresh", "/api/auth/check-email",
        "/api/auth/check-identity",  # US-013: Dual login support (email + username)
        "/api/system/auth-mode",  # Public endpoint for login mode detection
        "/api/telegram/auth/verify-user",
        "/api/telegram/auth/verify-email",
        "/api/telegram/auth/login-with-email",
        "/api/telegram/auth/refresh-token",
        "/api/telegram/health",
        "/api/telegram/internal/save-code"
    ]
)


# ============================================================================
# ROUTER REGISTRATION
# ============================================================================

# Module routers with prefixes
app.include_router(create_reports_router(), prefix="/api/reports", tags=["reports"])
app.include_router(create_data_entry_router(), prefix="/api/data-entry", tags=["data-entry"])
app.include_router(create_telegram_router(), prefix="/api/telegram", tags=["telegram"])

# Shared routers
auth_router = create_auth_router(prefix="", tags=["authentication"])
app.include_router(auth_router, prefix="/api/auth")

companies_router = create_companies_router(oracle_pool, tags=["companies"])
app.include_router(companies_router, prefix="/api/companies")

calendar_router = create_calendar_router(oracle_pool, tags=["calendar"])
app.include_router(calendar_router, prefix="/api/calendar")

system_router = create_system_router()
app.include_router(system_router, prefix="/api/system", tags=["system"])


# ============================================================================
# ROOT & HEALTH ENDPOINTS
# ============================================================================

@app.get("/")
async def root():
    """Root endpoint - API information."""
    return {
        "name": settings.app_name,
        "version": settings.app_version,
        "status": "running",
        "modules": ["reports", "data-entry", "telegram"],
        "docs": "/docs",
        "health": "/health"
    }


@app.get("/health")
async def health_check():
    """Health check endpoint with module status."""
    health_status = {
        "api": "healthy",
        "timestamp": datetime.utcnow().isoformat(),
        "modules": {}
    }

    # Check Oracle connection
    try:
        async with oracle_pool.get_connection() as conn:
            with conn.cursor() as cursor:
                cursor.execute("SELECT 1 FROM DUAL")
        health_status["modules"]["oracle"] = "connected"
    except Exception as e:
        health_status["modules"]["oracle"] = f"error: {str(e)}"

    # Check Reports cache
    try:
        from backend.modules.reports.cache import get_cache
        cache = get_cache()
        health_status["modules"]["reports_cache"] = "initialized" if cache else "disabled"
    except Exception as e:
        health_status["modules"]["reports_cache"] = f"error: {str(e)}"

    # Check Data Entry DB
    try:
        db_path = Path(settings.data_entry_sqlite_database_path)
        health_status["modules"]["data_entry_db"] = "exists" if db_path.exists() else "missing"
    except Exception as e:
        health_status["modules"]["data_entry_db"] = f"error: {str(e)}"

    # Check Telegram bot
    global telegram_bot_task
    if telegram_bot_task:
        if telegram_bot_task.done():
            health_status["modules"]["telegram_bot"] = "stopped"
        else:
            health_status["modules"]["telegram_bot"] = "running"
    else:
        health_status["modules"]["telegram_bot"] = "disabled"

    # Check OCR job worker
    global ocr_job_worker_running
    try:
        from backend.modules.data_entry.services.ocr.job_worker import is_running
        from backend.modules.data_entry.services.ocr.job_queue import job_queue

        if is_running():
            # Get queue stats
            stats = await job_queue.get_queue_stats()
            health_status["modules"]["ocr_worker"] = {
                "status": "running",
                "pending_jobs": stats.get("pending", 0),
                "processing_jobs": stats.get("processing", 0),
                "avg_time_seconds": stats.get("average_time_seconds", 0)
            }
        else:
            health_status["modules"]["ocr_worker"] = "stopped"
    except Exception as e:
        health_status["modules"]["ocr_worker"] = f"error: {str(e)}"

    # Check SSH tunnels
    global ssh_tunnel_monitoring
    try:
        from backend.shared.ssh_tunnel_manager import ssh_tunnel_manager
        health_status["modules"]["ssh_tunnels"] = ssh_tunnel_manager.get_status()
    except Exception as e:
        health_status["modules"]["ssh_tunnels"] = f"error: {str(e)}"

    return health_status


# ============================================================================
# MAIN ENTRY POINT
# ============================================================================

if __name__ == "__main__":
    import uvicorn

    uvicorn.run(
        "backend.main:app",
        host=settings.api_host,
        port=settings.api_port,
        reload=False,
        log_level="info"
    )