from django import forms
from django.contrib import admin
#from django.contrib.admin.utils import unquote
from django.core.urlresolvers import reverse
from django.db import models
#from django.shortcuts import redirect
from django.utils.translation import ugettext_lazy as _

from orchestra.admin import ExtendedModelAdmin
from orchestra.admin.utils import admin_link, admin_date
from orchestra.apps.accounts.admin import AccountAdminMixin

from . import settings
from .actions import download_bills, view_bill, close_bills, send_bills
from .filters import BillTypeListFilter
from .models import (Bill, Invoice, AmendmentInvoice, Fee, AmendmentFee, Budget,
        BillLine, BudgetLine)


class BillLineInline(admin.TabularInline):
    model = BillLine
    fields = ('description', 'rate', 'amount', 'tax', 'total', 'subtotal')
    readonly_fields = ('subtotal',)
    
    def subtotal(self, line):
        if line.total:
            subtotal = 0
            for subline in line.sublines.all():
                subtotal += subline.total
            return line.total - subtotal
        return ''
    
    def get_readonly_fields(self, request, obj=None):
        if obj and obj.status != Bill.OPEN:
            return self.fields
        return super(BillLineInline, self).get_readonly_fields(request, obj=obj)
    
    def has_add_permission(self, request):
        if request.__bill__ and request.__bill__.status != Bill.OPEN:
            return False
        return super(BillLineInline, self).has_add_permission(request)
    
    def has_delete_permission(self, request, obj=None):
        if obj and obj.status != Bill.OPEN:
            return False
        return super(BillLineInline, self).has_delete_permission(request, obj=obj)


class BudgetLineInline(admin.TabularInline):
    model = Budget
    fields = ('description', 'rate', 'amount', 'tax', 'total')


class BillAdmin(AccountAdminMixin, ExtendedModelAdmin):
    list_display = (
        'number', 'status', 'type_link', 'account_link', 'created_on_display',
        'num_lines', 'display_total'
    )
    list_filter = (BillTypeListFilter, 'status',)
    add_fields = ('account', 'type', 'status', 'due_on', 'comments')
    fieldsets = (
        (None, {
            'fields': ('number', 'display_total', 'account_link', 'type',
                       'status', 'due_on', 'comments'),
        }),
        (_("Raw"), {
            'classes': ('collapse',),
            'fields': ('html',),
        }),
    )
    actions = [download_bills, close_bills, send_bills]
    change_view_actions = [view_bill, download_bills, send_bills, close_bills]
    change_readonly_fields = ('account_link', 'type', 'status')
    readonly_fields = ('number', 'display_total')
    inlines = [BillLineInline]
    
    created_on_display = admin_date('created_on')
    
    def num_lines(self, bill):
        return bill.billlines__count
    num_lines.admin_order_field = 'billlines__count'
    num_lines.short_description = _("lines")
    
    def display_total(self, bill):
        return "%s &%s;" % (bill.total, settings.BILLS_CURRENCY.lower())
    display_total.allow_tags = True
    display_total.short_description = _("total")
    display_total.admin_order_field = 'total'
    
    def type_link(self, bill):
        bill_type = bill.type.lower()
        url = reverse('admin:bills_%s_changelist' % bill_type)
        return '<a href="%s">%s</a>' % (url, bill.get_type_display())
    type_link.allow_tags = True
    type_link.short_description = _("type")
    type_link.admin_order_field = 'type'
    
    def get_readonly_fields(self, request, obj=None):
        fields = super(BillAdmin, self).get_readonly_fields(request, obj=obj)
        if obj and obj.status != Bill.OPEN:
            fields += self.add_fields
        return fields
    
    def get_fieldsets(self, request, obj=None):
        fieldsets = super(BillAdmin, self).get_fieldsets(request, obj=obj)
        if obj and obj.status == obj.OPEN:
            fieldsets = (fieldsets[0],)
        return fieldsets
    
    def get_change_view_actions(self, obj=None):
        actions = super(BillAdmin, self).get_change_view_actions(obj)
        discard = []
        if obj:
            if obj.status != Bill.OPEN:
                discard = ['close_bills']
            if obj.status != Bill.CLOSED:
                discard = ['send_bills']
        if not discard:
            return actions
        return [action for action in actions if action.__name__ not in discard]
    
    def get_inline_instances(self, request, obj=None):
        if self.model is Budget:
            self.inlines = [BudgetLineInline]
        # Make parent object available for inline.has_add_permission()
        request.__bill__ = obj
        return super(BillAdmin, self).get_inline_instances(request, obj=obj)
    
    def formfield_for_dbfield(self, db_field, **kwargs):
        """ Make value input widget bigger """
        if db_field.name == 'comments':
            kwargs['widget'] = forms.Textarea(attrs={'cols': 70, 'rows': 4})
        if db_field.name == 'html':
            kwargs['widget'] = forms.Textarea(attrs={'cols': 150, 'rows': 20})
        return super(BillAdmin, self).formfield_for_dbfield(db_field, **kwargs)
        
    def get_queryset(self, request):
        qs = super(BillAdmin, self).get_queryset(request)
        qs = qs.annotate(models.Count('billlines'))
        qs = qs.prefetch_related('billlines', 'billlines__sublines')
        return qs

#    def change_view(self, request, object_id, **kwargs):
#        opts = self.model._meta
#        if opts.module_name == 'bill':
#            obj = self.get_object(request, unquote(object_id))
#            return redirect(
#                reverse('admin:bills_%s_change' % obj.type.lower(), args=[obj.pk]))
#        return super(BillAdmin, self).change_view(request, object_id, **kwargs)


admin.site.register(Bill, BillAdmin)
admin.site.register(Invoice, BillAdmin)
admin.site.register(AmendmentInvoice, BillAdmin)
admin.site.register(Fee, BillAdmin)
admin.site.register(AmendmentFee, BillAdmin)
admin.site.register(Budget, BillAdmin)