from django.shortcuts import render, get_object_or_404, redirect
from django.contrib.auth.decorators import login_required
from django.contrib import messages
from django.http import JsonResponse
from django.views.decorators.http import require_http_methods
from django.core.paginator import Paginator
from .models import PostgresCluster, PostgresInstance, ClusterUser, ClusterDatabase
from .forms import PostgresClusterForm, ClusterUserForm, ClusterDatabaseForm


@login_required
def cluster_list(request):
    """Display list of all clusters."""
    clusters = PostgresCluster.objects.filter(created_by=request.user)
    
    # Filtering
    status_filter = request.GET.get('status')
    if status_filter:
        clusters = clusters.filter(status=status_filter)
    
    # Pagination
    paginator = Paginator(clusters, 10)
    page_number = request.GET.get('page')
    page_obj = paginator.get_page(page_number)
    
    context = {
        'page_obj': page_obj,
        'status_choices': PostgresCluster._meta.get_field('status').choices,
    }
    return render(request, 'clusters/cluster_list.html', context)


@login_required
def cluster_create(request):
    """Create a new Postgres cluster."""
    if request.method == 'POST':
        form = PostgresClusterForm(request.POST)
        if form.is_valid():
            cluster = form.save(commit=False)
            cluster.created_by = request.user
            cluster.save()
            messages.success(request, f'Cluster "{cluster.name}" created successfully.')
            return redirect('clusters:cluster_detail', cluster_id=cluster.id)
    else:
        form = PostgresClusterForm()
    
    context = {
        'form': form,
        'title': 'Create New Cluster',
    }
    return render(request, 'clusters/cluster_form.html', context)


@login_required
def cluster_detail(request, cluster_id):
    """Display detailed information about a cluster."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    context = {
        'cluster': cluster,
        'instances': cluster.instances.all(),
        'users': cluster.users.all(),
        'databases': cluster.databases.all(),
    }
    return render(request, 'clusters/cluster_detail.html', context)


@login_required
def cluster_edit(request, cluster_id):
    """Edit an existing cluster."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    if request.method == 'POST':
        form = PostgresClusterForm(request.POST, instance=cluster)
        if form.is_valid():
            form.save()
            messages.success(request, f'Cluster "{cluster.name}" updated successfully.')
            return redirect('clusters:cluster_detail', cluster_id=cluster.id)
    else:
        form = PostgresClusterForm(instance=cluster)
    
    context = {
        'form': form,
        'cluster': cluster,
        'title': f'Edit Cluster: {cluster.name}',
    }
    return render(request, 'clusters/cluster_form.html', context)


@login_required
def cluster_delete(request, cluster_id):
    """Delete a cluster."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    if request.method == 'POST':
        cluster_name = cluster.name
        cluster.delete()
        messages.success(request, f'Cluster "{cluster_name}" deleted successfully.')
        return redirect('clusters:cluster_list')
    
    context = {
        'cluster': cluster,
    }
    return render(request, 'clusters/cluster_confirm_delete.html', context)


@login_required
@require_http_methods(["POST"])
def cluster_start(request, cluster_id):
    """Start a cluster."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    try:
        # TODO: Implement actual cluster start logic
        cluster.status = 'starting'
        cluster.save()
        messages.success(request, f'Starting cluster "{cluster.name}"...')
    except Exception as e:
        messages.error(request, f'Failed to start cluster: {str(e)}')
    
    return redirect('clusters:cluster_detail', cluster_id=cluster.id)


@login_required
@require_http_methods(["POST"])
def cluster_stop(request, cluster_id):
    """Stop a cluster."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    try:
        # TODO: Implement actual cluster stop logic
        cluster.status = 'stopping'
        cluster.save()
        messages.success(request, f'Stopping cluster "{cluster.name}"...')
    except Exception as e:
        messages.error(request, f'Failed to stop cluster: {str(e)}')
    
    return redirect('clusters:cluster_detail', cluster_id=cluster.id)


@login_required
@require_http_methods(["POST"])
def cluster_restart(request, cluster_id):
    """Restart a cluster."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    try:
        # TODO: Implement actual cluster restart logic
        cluster.status = 'starting'
        cluster.save()
        messages.success(request, f'Restarting cluster "{cluster.name}"...')
    except Exception as e:
        messages.error(request, f'Failed to restart cluster: {str(e)}')
    
    return redirect('clusters:cluster_detail', cluster_id=cluster.id)


@login_required
@require_http_methods(["POST"])
def cluster_update(request, cluster_id):
    """Update a cluster (rolling update)."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    try:
        # TODO: Implement actual rolling update logic
        cluster.status = 'updating'
        cluster.save()
        messages.success(request, f'Updating cluster "{cluster.name}"...')
    except Exception as e:
        messages.error(request, f'Failed to update cluster: {str(e)}')
    
    return redirect('clusters:cluster_detail', cluster_id=cluster.id)


@login_required
def cluster_users(request, cluster_id):
    """Manage users for a cluster."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    if request.method == 'POST':
        form = ClusterUserForm(request.POST)
        if form.is_valid():
            user = form.save(commit=False)
            user.cluster = cluster
            user.created_by = request.user
            user.save()
            messages.success(request, f'User "{user.username}" created successfully.')
            return redirect('clusters:cluster_users', cluster_id=cluster.id)
    else:
        form = ClusterUserForm()
    
    context = {
        'cluster': cluster,
        'form': form,
        'users': cluster.users.all(),
    }
    return render(request, 'clusters/cluster_users.html', context)


@login_required
def cluster_databases(request, cluster_id):
    """Manage databases for a cluster."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    if request.method == 'POST':
        form = ClusterDatabaseForm(request.POST)
        if form.is_valid():
            database = form.save(commit=False)
            database.cluster = cluster
            database.save()
            messages.success(request, f'Database "{database.name}" created successfully.')
            return redirect('clusters:cluster_databases', cluster_id=cluster.id)
    else:
        form = ClusterDatabaseForm()
    
    context = {
        'cluster': cluster,
        'form': form,
        'databases': cluster.databases.all(),
    }
    return render(request, 'clusters/cluster_databases.html', context)


@login_required
def cluster_instances(request, cluster_id):
    """View instances for a cluster."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    context = {
        'cluster': cluster,
        'instances': cluster.instances.all(),
    }
    return render(request, 'clusters/cluster_instances.html', context)


@login_required
def cluster_status_api(request, cluster_id):
    """API endpoint to get cluster status."""
    cluster = get_object_or_404(PostgresCluster, id=cluster_id, created_by=request.user)
    
    data = {
        'id': cluster.id,
        'name': cluster.name,
        'status': cluster.status,
        'instances': [
            {
                'id': instance.id,
                'name': instance.name,
                'type': instance.instance_type,
                'status': instance.status,
                'host': instance.host,
                'port': instance.port,
                'cpu_usage': instance.cpu_usage,
                'memory_usage': instance.memory_usage,
                'disk_usage': instance.disk_usage,
            }
            for instance in cluster.instances.all()
        ]
    }
    
    return JsonResponse(data)