import logging

import pendulum
from fastapi import APIRouter

from app.config import get_settings

logger = logging.getLogger(f"{__name__}.health")

router = APIRouter()
settings = get_settings()


@router.get("/health")
async def health_check():
    """Health check endpoint"""
    return {
        "status": "healthy",
        "timestamp": pendulum.now("UTC").to_iso8601_string(),
        "environment": settings.app_env,
        "version": "1.0.0",
    }


@router.get("/health/db")
async def database_health():
    """Database health check"""
    from sqlalchemy import text

    from app.database.session import engine

    try:
        async with engine.connect() as conn:
            await conn.execute(text("SELECT 1"))

        return {
            "status": "healthy",
            "database": "connected",
            "timestamp": pendulum.now("UTC").to_iso8601_string(),
        }
    except Exception as e:
        logger.error(f"Database health check failed: {e}")
        return {
            "status": "unhealthy",
            "database": "disconnected",
            "error": str(e),
            "timestamp": pendulum.now("UTC").to_iso8601_string(),
        }


@router.get("/health/memory")
async def memory_health():
    """
    Memory usage health check for game state management.

    Returns memory statistics including:
    - active_games: Number of games currently in memory
    - max_games: Configured limit
    - usage_percent: Current usage as percentage of limit
    - oldest_game_hours: Age of oldest game in hours
    - status: healthy (<75%), warning (75-90%), critical (>90%)
    """
    from app.core.state_manager import state_manager

    stats = state_manager.get_memory_stats()

    # Determine health status based on usage percentage
    if stats["max_games"] > 0:
        usage_pct = (stats["active_games"] / stats["max_games"]) * 100
    else:
        usage_pct = 0

    if usage_pct > 90:
        status = "critical"
    elif usage_pct > 75:
        status = "warning"
    else:
        status = "healthy"

    return {
        "status": status,
        "usage_percent": round(usage_pct, 1),
        "active_games": stats["active_games"],
        "max_games": stats["max_games"],
        "oldest_game_hours": round(stats["oldest_game_hours"], 2),
        "total_lineups_cached": stats["total_lineups_cached"],
        "total_locks": stats["total_locks"],
        "idle_timeout_hours": settings.game_idle_timeout_hours,
        "eviction_interval_minutes": settings.game_eviction_interval_minutes,
        "timestamp": pendulum.now("UTC").to_iso8601_string(),
    }


@router.get("/health/pool")
async def connection_pool_health():
    """
    Database connection pool health check.

    Returns pool statistics including:
    - pool_size: Configured base pool size
    - max_overflow: Maximum overflow connections allowed
    - available: Connections available for use
    - in_use: Connections currently checked out
    - overflow_active: Overflow connections in use
    - usage_percent: Current usage as percentage of total capacity
    - status: healthy (<75%), warning (75-90%), critical (>90%)
    - recent_history: Last 5 usage snapshots
    """
    from app.monitoring.pool_monitor import pool_monitor

    if not pool_monitor:
        return {
            "status": "unknown",
            "message": "Pool monitor not initialized",
            "timestamp": pendulum.now("UTC").to_iso8601_string(),
        }

    health = pool_monitor.get_health_status()
    history = pool_monitor.get_history(limit=5)

    return {
        **health,
        "recent_history": history,
    }


@router.get("/health/full")
async def full_health():
    """
    Comprehensive health check aggregating all subsystems.

    Returns overall status based on worst-case component status.
    Components checked: database connectivity, memory usage, connection pool.
    """
    from sqlalchemy import text

    from app.core.state_manager import state_manager
    from app.database.session import engine
    from app.monitoring.pool_monitor import pool_monitor

    components = {}

    # Database connectivity
    try:
        async with engine.connect() as conn:
            await conn.execute(text("SELECT 1"))
        components["database"] = {"status": "healthy"}
    except Exception as e:
        logger.error(f"Database health check failed: {e}")
        components["database"] = {"status": "critical", "error": str(e)}

    # Memory/game state
    try:
        stats = state_manager.get_memory_stats()
        if stats["max_games"] > 0:
            usage_pct = (stats["active_games"] / stats["max_games"]) * 100
        else:
            usage_pct = 0

        if usage_pct > 90:
            mem_status = "critical"
        elif usage_pct > 75:
            mem_status = "warning"
        else:
            mem_status = "healthy"

        components["memory"] = {
            "status": mem_status,
            "usage_percent": round(usage_pct, 1),
        }
    except Exception as e:
        logger.error(f"Memory health check failed: {e}")
        components["memory"] = {"status": "unknown", "error": str(e)}

    # Connection pool
    if pool_monitor:
        try:
            pool_health = pool_monitor.get_health_status()
            components["pool"] = {
                "status": pool_health["status"],
                "usage_percent": pool_health["usage_percent"],
            }
        except Exception as e:
            logger.error(f"Pool health check failed: {e}")
            components["pool"] = {"status": "unknown", "error": str(e)}
    else:
        components["pool"] = {"status": "unknown", "message": "Not initialized"}

    # Aggregate status (worst case wins)
    statuses = [c.get("status", "unknown") for c in components.values()]
    if "critical" in statuses:
        overall = "critical"
    elif "warning" in statuses:
        overall = "warning"
    elif "unknown" in statuses:
        overall = "degraded"
    else:
        overall = "healthy"

    return {
        "status": overall,
        "components": components,
        "timestamp": pendulum.now("UTC").to_iso8601_string(),
    }