from django.contrib import messages
from django.db.models.deletion import ProtectedError
from django.shortcuts import redirect, render
from django.urls import reverse_lazy
from django.views.generic import CreateView, DeleteView, ListView, UpdateView

from .forms import DividendoForm, DivisaForm, OperacionForm, ValorForm
from .models import Dividendo, Divisa, Operacion, Valor
from .services import (
    actualizar_cambios,
    actualizar_precios,
    desglose_fifo,
    posiciones,
    resumen_fiscal,
    totales,
)


class CancelarUrlMixin:
    """Aporta la URL de cancelación al formulario (vuelve atrás si hay referer)."""

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['cancelar_url'] = self.request.META.get('HTTP_REFERER') or str(self.success_url)
        return ctx


def dashboard(request):
    pos = posiciones()
    context = {
        'posiciones': pos,
        'abiertas': [p for p in pos if p['acciones'] > 0],
        'cerradas': [p for p in pos if p['acciones'] == 0],
        'totales': totales(pos),
    }
    return render(request, 'cartera/dashboard.html', context)


def actualizar(request):
    if request.method == 'POST':
        cambios, errores_cambios = actualizar_cambios()
        if cambios:
            messages.success(request, f'Cambios de moneda actualizados: {cambios}')
        for par, motivo in errores_cambios:
            messages.warning(request, f'{par}: {motivo}')
        correctos, errores = actualizar_precios()
        if correctos:
            messages.success(request, f'Precios actualizados: {correctos}')
        for ticker, motivo in errores:
            messages.warning(request, f'{ticker}: {motivo}')
    return redirect('cartera:dashboard')


def fifo(request):
    filas = desglose_fifo()
    context = {
        'filas': filas,
        'fiscal': resumen_fiscal(filas),
        'total': sum((f['resultado_eur'] or 0 for f in filas), start=0),
    }
    return render(request, 'cartera/fifo.html', context)


class OperacionListView(ListView):
    model = Operacion
    template_name = 'cartera/operacion_list.html'
    context_object_name = 'operaciones'

    def get_queryset(self):
        qs = Operacion.objects.select_related('valor', 'valor__divisa').order_by('-fecha', '-pk')
        valor = self.request.GET.get('valor')
        if valor:
            qs = qs.filter(valor_id=valor)
        return qs

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['valores'] = Valor.objects.order_by('ticker')
        ctx['valor_filtro'] = self.request.GET.get('valor', '')
        return ctx


class OperacionCreateView(CancelarUrlMixin, CreateView):
    model = Operacion
    form_class = OperacionForm
    template_name = 'cartera/form.html'
    success_url = reverse_lazy('cartera:operaciones')
    titulo = 'Nueva operación'

    def form_valid(self, form):
        messages.success(self.request, 'Operación registrada')
        return super().form_valid(form)


class OperacionUpdateView(CancelarUrlMixin, UpdateView):
    model = Operacion
    form_class = OperacionForm
    template_name = 'cartera/form.html'
    success_url = reverse_lazy('cartera:operaciones')
    titulo = 'Editar operación'

    def form_valid(self, form):
        messages.success(self.request, 'Operación actualizada')
        return super().form_valid(form)


class OperacionDeleteView(CancelarUrlMixin, DeleteView):
    model = Operacion
    template_name = 'cartera/confirm_delete.html'
    success_url = reverse_lazy('cartera:operaciones')
    titulo = 'Eliminar operación'

    def form_valid(self, form):
        messages.success(self.request, 'Operación eliminada')
        return super().form_valid(form)


class DividendoListView(ListView):
    model = Dividendo
    template_name = 'cartera/dividendo_list.html'
    context_object_name = 'dividendos'
    queryset = Dividendo.objects.select_related('valor')


class DividendoCreateView(CancelarUrlMixin, CreateView):
    model = Dividendo
    form_class = DividendoForm
    template_name = 'cartera/form.html'
    success_url = reverse_lazy('cartera:dividendos')
    titulo = 'Nuevo dividendo'

    def form_valid(self, form):
        messages.success(self.request, 'Dividendo registrado')
        return super().form_valid(form)


class DividendoUpdateView(CancelarUrlMixin, UpdateView):
    model = Dividendo
    form_class = DividendoForm
    template_name = 'cartera/form.html'
    success_url = reverse_lazy('cartera:dividendos')
    titulo = 'Editar dividendo'

    def form_valid(self, form):
        messages.success(self.request, 'Dividendo actualizado')
        return super().form_valid(form)


class DividendoDeleteView(CancelarUrlMixin, DeleteView):
    model = Dividendo
    template_name = 'cartera/confirm_delete.html'
    success_url = reverse_lazy('cartera:dividendos')
    titulo = 'Eliminar dividendo'

    def form_valid(self, form):
        messages.success(self.request, 'Dividendo eliminado')
        return super().form_valid(form)


class ValorListView(ListView):
    model = Valor
    template_name = 'cartera/valor_list.html'
    context_object_name = 'valores'


class ValorCreateView(CancelarUrlMixin, CreateView):
    model = Valor
    form_class = ValorForm
    template_name = 'cartera/form.html'
    success_url = reverse_lazy('cartera:valores')
    titulo = 'Nuevo valor'

    def form_valid(self, form):
        messages.success(self.request, 'Valor creado')
        return super().form_valid(form)


class ValorUpdateView(CancelarUrlMixin, UpdateView):
    model = Valor
    form_class = ValorForm
    template_name = 'cartera/form.html'
    success_url = reverse_lazy('cartera:valores')
    titulo = 'Editar valor'

    def form_valid(self, form):
        messages.success(self.request, 'Valor actualizado')
        return super().form_valid(form)


class ValorDeleteView(CancelarUrlMixin, DeleteView):
    model = Valor
    template_name = 'cartera/confirm_delete.html'
    success_url = reverse_lazy('cartera:valores')
    titulo = 'Eliminar valor'

    def form_valid(self, form):
        messages.success(self.request, 'Valor eliminado (con todas sus operaciones)')
        return super().form_valid(form)


class DivisaListView(ListView):
    model = Divisa
    template_name = 'cartera/divisa_list.html'
    context_object_name = 'divisas'


class DivisaCreateView(CancelarUrlMixin, CreateView):
    model = Divisa
    form_class = DivisaForm
    template_name = 'cartera/form.html'
    success_url = reverse_lazy('cartera:divisas')
    titulo = 'Nueva divisa'

    def form_valid(self, form):
        messages.success(self.request, 'Divisa creada')
        return super().form_valid(form)


class DivisaUpdateView(CancelarUrlMixin, UpdateView):
    model = Divisa
    form_class = DivisaForm
    template_name = 'cartera/form.html'
    success_url = reverse_lazy('cartera:divisas')
    titulo = 'Editar divisa'

    def form_valid(self, form):
        messages.success(self.request, 'Divisa actualizada')
        return super().form_valid(form)


class DivisaDeleteView(CancelarUrlMixin, DeleteView):
    model = Divisa
    template_name = 'cartera/confirm_delete.html'
    success_url = reverse_lazy('cartera:divisas')
    titulo = 'Eliminar divisa'

    def post(self, request, *args, **kwargs):
        try:
            return super().post(request, *args, **kwargs)
        except ProtectedError:
            messages.error(
                request,
                'No se puede eliminar: hay valores que usan esta divisa.',
            )
            return redirect('cartera:divisas')