"""Analytics SubApp: PostHog for product analytics + local usage summary from session data."""

import asyncio
import logging
import platform
from contextlib import asynccontextmanager
from datetime import datetime
from typing import Optional

from pydantic import InstanceOf

from backend.config.Apps import SubApp
from backend.apps.analytics.collector import init as init_collector, shutdown as shutdown_collector, record, identify
from backend.apps.analytics.usage_summary import load_all_sessions, compute_session_stats, enrich_with_nine_router

from backend.apps.agents.manager.agent_manager import agent_manager
from backend.apps.settings.settings import load_settings, _save_settings
from backend.apps.agents.manager.agent_manager import agent_manager

from backend.apps.nine_router import get_usage_stats, is_running as _9r_running



logger = logging.getLogger(__name__)

APP_VERSION = "1.0.20"

_heartbeat_task: Optional[InstanceOf[asyncio.Task]] = None


async def _heartbeat_loop():
    """Send a heartbeat event every 60 seconds for usage-time tracking and cost snapshots."""
    while True:
        await asyncio.sleep(60)
        try:
            props = {
                "active_session_count": len(agent_manager.sessions),
            }

            try:
                if _9r_running():
                    stats = await get_usage_stats()
                    if stats:
                        props["nine_router_total_cost"] = stats.get("totalCost", 0)
                        props["nine_router_total_prompt_tokens"] = stats.get("totalPromptTokens", 0)
                        props["nine_router_total_completion_tokens"] = stats.get("totalCompletionTokens", 0)
                        props["nine_router_total_requests"] = stats.get("totalRequests", 0)
                        for model_name, model_data in (stats.get("byModel") or {}).items():
                            safe_name = model_name.replace(".", "_").replace("-", "_")[:40]
                            props[f"cost_model_{safe_name}"] = model_data.get("cost", 0)
                            props[f"tokens_model_{safe_name}"] = model_data.get("promptTokens", 0) + model_data.get("completionTokens", 0)
            except Exception:
                pass

            record("app.heartbeat", props)

            if "nine_router_total_cost" in props:
                record("cost.snapshot", {
                    "total_cost_usd": props["nine_router_total_cost"],
                    "total_prompt_tokens": props.get("nine_router_total_prompt_tokens", 0),
                    "total_completion_tokens": props.get("nine_router_total_completion_tokens", 0),
                    "total_requests": props.get("nine_router_total_requests", 0),
                })
        except Exception:
            pass


@asynccontextmanager
async def analytics_lifespan():
    global _heartbeat_task

    init_collector()
    logger.info("PostHog analytics initialised")

    try:
        settings = load_settings()

        is_first_open = settings.first_opened_at is None
        if is_first_open:
            settings.first_opened_at = datetime.now().isoformat()
            _save_settings(settings)

        days_since_install = 0
        if settings.first_opened_at:
            try:
                first = datetime.fromisoformat(settings.first_opened_at[:19])
                days_since_install = (datetime.now() - first).days
            except Exception:
                pass

        providers = []
        if getattr(settings, "anthropic_api_key", None):
            providers.append("anthropic")
        if getattr(settings, "openai_api_key", None):
            providers.append("openai")
        if getattr(settings, "google_api_key", None):
            providers.append("gemini")
        if getattr(settings, "openrouter_api_key", None):
            providers.append("openrouter")
        for cp in getattr(settings, "custom_providers", []):
            providers.append(cp.name)

        record("app.opened", {
            "os": platform.system(),
            "platform": platform.platform(),
            "provider_count": len(providers),
            "providers": providers,
            "is_first_open": is_first_open,
            "days_since_install": days_since_install,
            "app_version": APP_VERSION,
        })

        identify({
            "providers_configured": providers,
            "provider_count": len(providers),
            "app_version": APP_VERSION,
        })
    except Exception as e:
        logger.debug(f"Analytics startup event failed (non-critical): {e}")

    _heartbeat_task = asyncio.create_task(_heartbeat_loop())

    yield

    if _heartbeat_task:
        _heartbeat_task.cancel()
        try:
            await _heartbeat_task
        except asyncio.CancelledError:
            pass
        _heartbeat_task = None

    shutdown_collector()
    logger.info("PostHog analytics shut down")


analytics = SubApp("analytics", analytics_lifespan)


@analytics.router.get("/usage-summary")
async def usage_summary():
    """Compute usage stats from persisted sessions for the Settings page."""

    sessions = load_all_sessions()
    for s in agent_manager.get_all_sessions():
        sessions.append(s.model_dump(mode="json"))

    stats = compute_session_stats(sessions)
    nine_router_stats = await get_usage_stats() if _9r_running() else None
    return enrich_with_nine_router(stats, nine_router_stats)