import os
from django.utils import timezone
from django.conf import settings
from rest_framework import viewsets, status
from rest_framework.decorators import action
from rest_framework.response import Response
from rest_framework.permissions import AllowAny
from .models import Simulation
from .serializers import SimulationSerializer
from .fenics_runner import run_simulation
from rest_framework.views import APIView
from DangVan.dangvan import compute_dang_van
import threading


class SimulationViewSet(viewsets.ModelViewSet):
    permission_classes = [AllowAny]
    queryset = Simulation.objects.all().order_by('-created_at')
    serializer_class = SimulationSerializer
    
    def create(self, request, *args, **kwargs):
        name = request.data.get('name', '')
        parameters = request.data.get('parameters', {})
        
        simulation = Simulation.objects.create(
            name=name,
            parameters=parameters,
            status='running'
        )
        
        thread = threading.Thread(
            target=self._run_simulation_async,
            args=(simulation.id, parameters)
        )
        thread.start()
        
        serializer = self.get_serializer(simulation)
        return Response(serializer.data, status=status.HTTP_201_CREATED)
    
    def _run_simulation_async(self, simulation_id, parameters):
        simulation = Simulation.objects.get(id=simulation_id)
        try:
            result = run_simulation(parameters)
            
            results_dir = os.path.join(settings.BASE_DIR, 'simulation_results')
            os.makedirs(results_dir, exist_ok=True)
            
            import shutil
            final_result_path = os.path.join(
                results_dir, 
                f'result_{simulation_id}.txt'
            )
            shutil.copy(result['results_file'], final_result_path)
            
            final_image_path = os.path.join(
                results_dir,
                f'result_{simulation_id}.png'
            )
            shutil.copy(result['image_file'], final_image_path)

            # Copy generated frames if present
            frames_meta = None
            frames_src = result.get('frames') or []
            if frames_src:
                frames_target_dir = os.path.join(results_dir, f'frames_{simulation_id}')
                os.makedirs(frames_target_dir, exist_ok=True)
                copied = []
                for fp in frames_src:
                    try:
                        basename = os.path.basename(fp)
                        dest = os.path.join(frames_target_dir, basename)
                        shutil.copy(fp, dest)
                        copied.append(f'simulation_results/frames_{simulation_id}/{basename}')
                    except Exception:
                        continue
                if copied:
                    frames_meta = {
                        'dir': f'simulation_results/frames_{simulation_id}',
                        'files': copied,
                        'count': len(copied),
                    }
            
            simulation.result_summary = {
                'final_max': result['final_max'],
                'final_mean': result['final_mean'],
                'time_series': result['time_series'],
                'frames': frames_meta
            }
            simulation.result_file_path = f'simulation_results/result_{simulation_id}.txt'
            simulation.result_image_path = f'simulation_results/result_{simulation_id}.png'
            simulation.status = 'completed'
            simulation.completed_at = timezone.now()
            simulation.save()
            
        except Exception as e:
            simulation.status = 'failed'
            simulation.error_message = str(e)
            simulation.save()
    
    @action(detail=True, methods=['get'])
    def result_image(self, request, pk=None):
        simulation = self.get_object()
        if simulation.result_image_path:
            image_path = os.path.join(settings.BASE_DIR, simulation.result_image_path)
            from django.http import FileResponse
            return FileResponse(open(image_path, 'rb'), content_type='image/png')
        return Response({'error': 'Aucune image disponible'}, status=404)

    @action(detail=True, methods=['get'], url_path='frame/(?P<index>\\d+)')
    def frame(self, request, pk=None, index=None):
        simulation = self.get_object()
        frames = (simulation.result_summary or {}).get('frames') or {}
        files = frames.get('files') or []
        try:
            idx = int(index)
        except Exception:
            return Response({'error': 'Index invalide'}, status=400)
        if 0 <= idx < len(files):
            frame_rel = files[idx]
            frame_abs = os.path.join(settings.BASE_DIR, frame_rel)
            from django.http import FileResponse
            return FileResponse(open(frame_abs, 'rb'), content_type='image/png')
        return Response({'error': 'Frame non disponible'}, status=404)


class DangVanView(APIView):
    permission_classes = [AllowAny]

    def post(self, request):
        data = request.data or {}
        stress_series = data.get('stress_series')
        a = data.get('a')
        b = data.get('b')
        if stress_series is None or a is None or b is None:
            return Response({'error': 'Paramètres requis: stress_series, a, b'}, status=status.HTTP_400_BAD_REQUEST)
        try:
            result = compute_dang_van(stress_series, a, b)
            return Response(result, status=status.HTTP_200_OK)
        except Exception as e:
            return Response({'error': str(e)}, status=status.HTTP_400_BAD_REQUEST)