"""
API endpoints for simulation control.
"""
from typing import Dict, Optional, List
from fastapi import APIRouter, HTTPException, Depends
from pydantic import BaseModel
from sqlalchemy.orm import Session

from ..models.config import SimulationConfigModel
from ..models.results import (
    SimulationResultsModel,
    QueueStatisticsModel,
    TimeSeriesDataModel,
    HistogramDataModel
)
from ..core.simulation import Simulator
from ..analytics.jackson import JacksonAnalyzer
from ..analytics.comparison import compare_results
from ..database.connection import get_db
from ..models.database import SimulationRun


router = APIRouter(prefix="/api/simulation", tags=["simulation"])


# In-memory storage for simulation sessions
# In production, use Redis or a database
simulation_sessions: Dict[str, dict] = {}


class SimulationSessionResponse(BaseModel):
    """Response when starting a simulation."""
    session_id: str
    status: str
    message: str


@router.post("/start", response_model=SimulationSessionResponse)
async def start_simulation(config: SimulationConfigModel, db: Session = Depends(get_db)):
    """
    Start a new simulation with the given configuration.

    Args:
        config: Simulation configuration

    Returns:
        Session information
    """
    try:
        # Convert Pydantic model to internal config
        internal_config = config.to_simulation_config()

        # Create simulator
        simulator = Simulator(internal_config)

        # Run simulation (synchronous for now - could be async/background task)
        results = simulator.run()

        # Generate session ID
        import uuid
        session_id = str(uuid.uuid4())

        # Check stability (simple heuristic: max utilization)
        max_utilization = max(
            results.coordinator_stats["utilization"],
            max(s["utilization"] for s in results.server_stats.values()) if results.server_stats else 0
        )
        is_stable = max_utilization < 0.95

        # Convert to QueueStatisticsModel for serialization
        coordinator_stats = QueueStatisticsModel(
            queue_id="coordinator",
            service_rate=results.coordinator_stats["service_rate"],
            total_arrivals=results.coordinator_stats["total_arrivals"],
            total_departures=results.coordinator_stats["total_departures"],
            average_wait_time=results.coordinator_stats["average_wait_time"],
            average_service_time=results.coordinator_stats["average_service_time"],
            average_system_time=results.coordinator_stats["average_system_time"],
            utilization=results.coordinator_stats["utilization"]
        )

        server_stats = {}
        for server_id, stats in results.server_stats.items():
            server_stats[server_id] = QueueStatisticsModel(
                queue_id=server_id,
                service_rate=stats["service_rate"],
                total_arrivals=stats["total_arrivals"],
                total_departures=stats["total_departures"],
                average_wait_time=stats["average_wait_time"],
                average_service_time=stats["average_service_time"],
                average_system_time=stats["average_system_time"],
                utilization=stats["utilization"]
            )

        # Sauvegarder en base de données
        db_simulation = SimulationRun(
            id=session_id,
            config=config.model_dump(),
            total_requests_arrived=results.total_requests_arrived,
            total_requests_completed=results.total_requests_completed,
            average_system_time=results.average_system_time,
            average_customers_in_system=results.average_customers_in_system,
            is_stable=is_stable,
            coordinator_stats=coordinator_stats.model_dump(),
            server_stats={k: v.model_dump() for k, v in server_stats.items()},
            time_series=results.time_series_data,
            processing_time_histogram=results.histogram_data,
            status="completed"
        )
        db.add(db_simulation)
        db.commit()

        # Store results also in memory for backward compatibility
        simulation_sessions[session_id] = {
            "config": config.model_dump(),
            "results": results,
            "status": "completed"
        }

        return SimulationSessionResponse(
            session_id=session_id,
            status="completed",
            message="Simulation completed successfully"
        )

    except Exception as e:
        raise HTTPException(status_code=400, detail=str(e))


@router.get("/results/{session_id}")
async def get_simulation_results(session_id: str):
    """
    Get results for a completed simulation.

    Args:
        session_id: Session identifier

    Returns:
        Simulation results
    """
    if session_id not in simulation_sessions:
        raise HTTPException(status_code=404, detail="Session not found")

    session = simulation_sessions[session_id]
    results = session["results"]

    # Convert to response model
    coordinator_stats = QueueStatisticsModel(
        queue_id="coordinator",
        service_rate=results.coordinator_stats["service_rate"],
        total_arrivals=results.coordinator_stats["total_arrivals"],
        total_departures=results.coordinator_stats["total_departures"],
        average_wait_time=results.coordinator_stats["average_wait_time"],
        average_service_time=results.coordinator_stats["average_service_time"],
        average_system_time=results.coordinator_stats["average_system_time"],
        utilization=results.coordinator_stats["utilization"]
    )

    server_stats = {}
    for server_id, stats in results.server_stats.items():
        server_stats[server_id] = QueueStatisticsModel(
            queue_id=server_id,
            service_rate=stats["service_rate"],
            total_arrivals=stats["total_arrivals"],
            total_departures=stats["total_departures"],
            average_wait_time=stats["average_wait_time"],
            average_service_time=stats["average_service_time"],
            average_system_time=stats["average_system_time"],
            utilization=stats["utilization"]
        )

    # Check stability (simple heuristic: max utilization)
    max_utilization = max(
        results.coordinator_stats["utilization"],
        max(s["utilization"] for s in results.server_stats.values()) if results.server_stats else 0
    )
    is_stable = max_utilization < 0.95

    # Convert time series data if available
    time_series = None
    if results.time_series_data:
        time_series = TimeSeriesDataModel(
            timestamps=results.time_series_data["timestamps"],
            customers_in_system=results.time_series_data["customers_in_system"],
            customers_per_queue=results.time_series_data["customers_per_queue"],
            cumulative_arrivals_per_queue=results.time_series_data["cumulative_arrivals_per_queue"],
            cumulative_departures_per_queue=results.time_series_data["cumulative_departures_per_queue"]
        )

    # Convert histogram data if available
    histogram = None
    if results.histogram_data:
        histogram = HistogramDataModel(
            bins=results.histogram_data["bins"],
            frequencies=results.histogram_data["frequencies"],
            min_value=results.histogram_data["min_value"],
            max_value=results.histogram_data["max_value"],
            mean=results.histogram_data["mean"],
            std_dev=results.histogram_data["std_dev"]
        )

    response = SimulationResultsModel(
        config=session["config"],
        total_requests_arrived=results.total_requests_arrived,
        total_requests_completed=results.total_requests_completed,
        average_system_time=results.average_system_time,
        average_customers_in_system=results.average_customers_in_system,
        coordinator_stats=coordinator_stats,
        server_stats=server_stats,
        time_series=time_series,
        processing_time_histogram=histogram,
        is_stable=is_stable,
        stability_notes="High utilization detected" if not is_stable else None
    )

    return response


@router.delete("/results/{session_id}")
async def delete_simulation_results(session_id: str):
    """
    Delete simulation results.

    Args:
        session_id: Session identifier

    Returns:
        Confirmation message
    """
    if session_id not in simulation_sessions:
        raise HTTPException(status_code=404, detail="Session not found")

    del simulation_sessions[session_id]

    return {"message": "Session deleted successfully"}


@router.get("/simulations")
async def list_simulations(
    skip: int = 0,
    limit: int = 50,
    db: Session = Depends(get_db)
):
    """
    Liste toutes les simulations sauvegardées avec pagination.

    Args:
        skip: Nombre de simulations à ignorer
        limit: Nombre maximum de simulations à retourner
        db: Session de base de données

    Returns:
        Liste des simulations avec leurs métadonnées
    """
    simulations = db.query(SimulationRun)\
        .order_by(SimulationRun.created_at.desc())\
        .offset(skip)\
        .limit(limit)\
        .all()

    return {
        "simulations": [
            {
                "session_id": sim.id,
                "created_at": sim.created_at.isoformat(),
                "total_requests": sim.total_requests_completed,
                "is_stable": sim.is_stable,
                "arrival_rate": sim.config["arrival_rate"],
            }
            for sim in simulations
        ],
        "count": len(simulations)
    }


@router.post("/compare")
async def compare_simulations(
    session_ids: List[str],
    db: Session = Depends(get_db)
):
    """
    Compare plusieurs simulations sélectionnées.

    Args:
        session_ids: Liste des IDs de simulations à comparer
        db: Session de base de données

    Returns:
        Données de comparaison des simulations
    """
    simulations = db.query(SimulationRun)\
        .filter(SimulationRun.id.in_(session_ids))\
        .all()

    if len(simulations) != len(session_ids):
        raise HTTPException(status_code=404, detail="Some sessions not found")

    comparison = []
    for sim in simulations:
        comparison.append({
            "session_id": sim.id,
            "created_at": sim.created_at.isoformat(),
            "config": sim.config,
            "total_requests_completed": sim.total_requests_completed,
            "average_system_time": sim.average_system_time,
            "coordinator_stats": sim.coordinator_stats,
            "server_stats": sim.server_stats,
            "time_series": sim.time_series,
        })

    return {"simulations": comparison}


@router.get("/sessions")
async def list_simulation_sessions():
    """
    List all simulation sessions.

    Returns:
        List of session IDs and their status
    """
    sessions = []
    for session_id, session in simulation_sessions.items():
        sessions.append({
            "session_id": session_id,
            "status": session["status"],
            "total_requests": session["results"].total_requests_completed
        })

    return {"sessions": sessions, "count": len(sessions)}