"""
Endpoints API pour la génération de diagrammes PH.
"""

from fastapi import APIRouter, HTTPException, status
from typing import Dict, Any

from app.models.diagram import (
    DiagramRequest,
    DiagramResponse,
    DiagramError
)
from app.services.diagram_generator import DiagramGenerator
from app.core.refrigerant_loader import get_refrigerant
from collections import OrderedDict
import json


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


@router.post(
    "/ph",
    response_model=DiagramResponse,
    summary="Générer un diagramme Pression-Enthalpie",
    description="Génère un diagramme PH avec courbe de saturation et isothermes",
    status_code=status.HTTP_200_OK
)
async def generate_ph_diagram(request: DiagramRequest) -> DiagramResponse:
    """
    Génère un diagramme Pression-Enthalpie.
    
    Args:
        request: Paramètres du diagramme
        
    Returns:
        DiagramResponse avec image et/ou données
        
    Raises:
        HTTPException: Si erreur lors de la génération
    """
    try:
        # Charger le réfrigérant
        refrigerant = get_refrigerant(request.refrigerant)
        if refrigerant is None:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"Réfrigérant '{request.refrigerant}' non disponible"
            )
        
        # Créer le générateur
        generator = DiagramGenerator(refrigerant)
        
        # Configurer dimensions si PNG
        if request.format in ["png", "both"]:
            generator.fig_width = request.width / 100
            generator.fig_height = request.height / 100
            generator.dpi = request.dpi
        
        # Convertir cycle_points en tuples
        cycle_points_tuples = None
        if request.cycle_points:
            cycle_points_tuples = [
                (pt["enthalpy"], pt["pressure"]) 
                for pt in request.cycle_points
            ]
        
        # Simple in-memory LRU cache for diagram JSON results (keyed by request body)
        # Cache only JSON responses to avoid storing large PNG blobs in memory
        if not hasattr(generate_ph_diagram, "_diagram_cache"):
            generate_ph_diagram._diagram_cache = OrderedDict()
            generate_ph_diagram._cache_size = 50

        def _make_cache_key(req: DiagramRequest) -> str:
            # Use a stable JSON string of important fields as cache key
            def _serialize(v):
                # Pydantic BaseModel expose model_dump in v2; fall back to dict
                try:
                    if hasattr(v, 'model_dump'):
                        return v.model_dump()
                    elif hasattr(v, 'dict'):
                        return v.dict()
                except Exception:
                    pass
                return v

            key_obj = {
                "refrigerant": req.refrigerant,
                "pressure_range": _serialize(req.pressure_range),
                "include_isotherms": req.include_isotherms,
                "cycle_points": _serialize(req.cycle_points),
                "format": req.format,
            }
            return json.dumps(key_obj, sort_keys=True, separators=(",", ":"))

        cache_key = _make_cache_key(request)
        # If client requested JSON or both, try cache
        cached_result = None
        if request.format in ["json", "both"]:
            cached_result = generate_ph_diagram._diagram_cache.get(cache_key)

        if cached_result is not None:
            # move to end (most recently used)
            generate_ph_diagram._diagram_cache.move_to_end(cache_key)
            result = cached_result
            generation_time = 0.0
        else:
            import time
            start_time = time.time()

            result = generator.generate_complete_diagram(
                cycle_points=cycle_points_tuples,
                title=request.title,
                export_format=request.format
            )

            generation_time = (time.time() - start_time) * 1000  # ms
            # store JSON part in cache if present and format includes json
            if request.format in ["json", "both"] and "data" in result:
                # store only the data dictionary to keep cache small
                cache_entry = {"data": result.get("data")}
                generate_ph_diagram._diagram_cache[cache_key] = cache_entry
                # enforce cache size
                if len(generate_ph_diagram._diagram_cache) > generate_ph_diagram._cache_size:
                    generate_ph_diagram._diagram_cache.popitem(last=False)
        
        # Construire la réponse
        response_data = {
            "success": True,
            "metadata": {
                "generation_time_ms": round(generation_time, 2),
                "refrigerant": request.refrigerant,
                "export_format": request.format
            },
            "message": f"Diagramme PH généré pour {request.refrigerant}"
        }
        
        # Ajouter l'image si générée
        if "image_base64" in result:
            response_data["image"] = result["image_base64"]
            response_data["metadata"]["image_format"] = "png"
            response_data["metadata"]["image_width"] = request.width
            response_data["metadata"]["image_height"] = request.height
        
        # Ajouter les données si générées
        if "data" in result:
            response_data["data"] = result["data"]
        
        return DiagramResponse(**response_data)
        
    except HTTPException:
        raise
    except ValueError as e:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Paramètres invalides: {str(e)}"
        )
    except Exception as e:
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=f"Erreur génération diagramme: {str(e)}"
        )


@router.get(
    "/",
    summary="Types de diagrammes disponibles",
    response_model=Dict[str, Any]
)
async def list_diagram_types():
    """Liste les types de diagrammes disponibles."""
    return {
        "diagram_types": [
            {
                "type": "ph",
                "name": "Pression-Enthalpie",
                "description": "Diagramme log(P) vs h avec courbe de saturation et isothermes",
                "endpoint": "/api/v1/diagrams/ph"
            }
        ],
        "export_formats": ["png", "json", "both"],
        "supported_refrigerants": [
            "R12", "R22", "R32", "R134a", "R290", "R404A", "R410A",
            "R452A", "R454A", "R454B", "R502", "R507A", "R513A",
            "R515B", "R744", "R1233zd", "R1234ze"
        ]
    }