"""
Hold Slayer Gateway — FastAPI Application Entry Point.

Your personal AI-powered telephony platform.
Navigates IVRs, waits on hold, and connects you when a human answers.

Usage:
    uvicorn main:app --host 0.0.0.0 --port 8000 --reload
    
    # Or directly:
    python main.py
"""

import logging
import sys
from contextlib import asynccontextmanager

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles

from api import calls, call_flows, devices, websocket
from config import get_settings
from core.gateway import AIPSTNGateway
from db.database import close_db, init_db
from mcp_server.server import create_mcp_server

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s | %(levelname)-7s | %(name)s | %(message)s",
    datefmt="%H:%M:%S",
    stream=sys.stdout,
)
logger = logging.getLogger(__name__)


def _handle_db_error(exc: Exception) -> None:
    """Log a clear, human-readable database error and exit cleanly."""
    # Walk the exception chain to find the root asyncpg/psycopg cause
    cause = getattr(exc, "__cause__", None) or getattr(exc, "__context__", None)
    root = cause or exc
    root_type = type(root).__name__
    root_msg = str(root)

    if "InvalidPasswordError" in root_type or "password authentication failed" in root_msg:
        logger.critical(
            "\n"
            "❌  Database authentication failed — wrong password.\n"
            "    The password in DATABASE_URL does not match the PostgreSQL user.\n"
            "    Fix DATABASE_URL in your .env file and restart.\n"
            "    Default: DATABASE_URL=postgresql+asyncpg://holdslayer:changeme@localhost:5432/holdslayer"
        )
    elif "InvalidCatalogNameError" in root_type or "does not exist" in root_msg:
        logger.critical(
            "\n"
            "❌  Database does not exist.\n"
            "    Create it first:  createdb holdslayer\n"
            "    Or update DATABASE_URL in your .env file."
        )
    elif (
        "Connection refused" in root_msg
        or "could not connect" in root_msg.lower()
    ):
        logger.critical(
            "\n"
            "\u274c  Cannot reach PostgreSQL \u2014 connection refused.\n"
            "    Is PostgreSQL running? Check DATABASE_URL in your .env file."
        )
    elif (
        "nodename nor servname" in root_msg
        or "Name or service not known" in root_msg
    ):
        logger.critical(
            "\n"
            f"❌  Cannot resolve the database hostname.\n"
            f"    Check the host in DATABASE_URL in your .env file. (detail: {root_msg})"
        )
    else:
        logger.critical(
            f"\n❌  Database initialisation failed: {root_msg}\n"
            f"    Check DATABASE_URL in your .env file."
        )

    sys.exit(1)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Startup: Initialize database, SIP engine, and services."""
    settings = get_settings()

    # Initialize database
    logger.info("Initializing database...")
    try:
        await init_db()
    except Exception as e:
        _handle_db_error(e)

    # Boot the telephony engine
    gateway = AIPSTNGateway.from_config()
    await gateway.start()
    app.state.gateway = gateway

    # Start auxiliary services
    from services.notification import NotificationService
    from services.recording import RecordingService
    from services.call_analytics import CallAnalytics
    from services.call_flow_learner import CallFlowLearner

    notification_svc = NotificationService(gateway.event_bus, settings)
    await notification_svc.start()
    app.state.notification_service = notification_svc

    recording_svc = RecordingService()
    await recording_svc.start()
    app.state.recording_service = recording_svc

    analytics_svc = CallAnalytics()
    app.state.analytics_service = analytics_svc

    flow_learner = CallFlowLearner()
    app.state.flow_learner = flow_learner

    # Create and mount MCP server
    mcp = create_mcp_server(gateway)
    app.state.mcp = mcp

    logger.info("=" * 60)
    logger.info("🔥 Hold Slayer Gateway is LIVE")
    # Show a usable URL — 0.0.0.0 is the bind address, not a browser URL
    display_host = "localhost" if settings.host in ("0.0.0.0", "::") else settings.host
    # When launched via `uvicorn main:app --port XXXX`, the CLI --port arg
    # takes precedence over settings.port (which comes from .env).
    display_port = settings.port
    for i, arg in enumerate(sys.argv):
        if arg in ("--port", "-p") and i + 1 < len(sys.argv):
            try:
                display_port = int(sys.argv[i + 1])
            except ValueError:
                pass
    logger.info(f"   API:       http://{display_host}:{display_port}")
    logger.info(f"   API Docs:  http://{display_host}:{display_port}/docs")
    logger.info(f"   WebSocket: ws://{display_host}:{display_port}/ws/events")
    logger.info(f"   MCP:       Available via FastMCP")
    logger.info("=" * 60)

    yield

    # Shutdown
    logger.info("Shutting down Hold Slayer Gateway...")
    await notification_svc.stop()
    await gateway.stop()
    await close_db()
    logger.info("Gateway shut down cleanly. 👋")


app = FastAPI(
    title="Hold Slayer Gateway",
    description=(
        "🗡️ AI PSTN Gateway — Navigate IVRs, wait on hold, "
        "and connect you when a human answers.\n\n"
        "## Quick Start\n"
        "1. **POST /api/calls/hold-slayer** — Launch the Hold Slayer\n"
        "2. **GET /api/calls/{call_id}** — Check call status\n"
        "3. **WS /ws/events** — Real-time event stream\n"
        "4. **GET /api/call-flows** — Manage stored IVR trees\n"
    ),
    version="0.1.0",
    lifespan=lifespan,
)

# === API Routes ===
app.include_router(calls.router, prefix="/api/calls", tags=["Calls"])
app.include_router(call_flows.router, prefix="/api/call-flows", tags=["Call Flows"])
app.include_router(devices.router, prefix="/api/devices", tags=["Devices"])
app.include_router(websocket.router, prefix="/ws", tags=["WebSocket"])


# === Root Endpoint ===
@app.get("/", tags=["System"])
async def root():
    """Gateway root — health check and quick status."""
    gateway = getattr(app.state, "gateway", None)
    if gateway:
        status = await gateway.status()
        return {
            "name": "Hold Slayer Gateway",
            "version": "0.1.0",
            "status": "running",
            "uptime": status["uptime"],
            "active_calls": status["active_calls"],
            "trunk": status["trunk"],
        }
    return {
        "name": "Hold Slayer Gateway",
        "version": "0.1.0",
        "status": "starting",
    }


@app.get("/health", tags=["System"])
async def health():
    """Health check endpoint."""
    gateway = getattr(app.state, "gateway", None)
    ready = gateway is not None and await gateway.sip_engine.is_ready()
    trunk_status = await gateway.sip_engine.get_trunk_status() if gateway else {"registered": False}
    return {
        "status": "healthy" if ready else "degraded",
        "gateway": "ready" if gateway else "not initialized",
        "sip_engine": "ready" if ready else "not ready",
        "sip_trunk": {
            "registered": trunk_status.get("registered", False),
            "host": trunk_status.get("host"),
            "mock": trunk_status.get("mock", False),
            "reason": trunk_status.get("reason"),
        },
    }


if __name__ == "__main__":
    import uvicorn

    settings = get_settings()
    uvicorn.run(
        "main:app",
        host=settings.host,
        port=settings.port,
        reload=settings.debug,
        log_level=settings.log_level,
    )