"""
Billing Module Admin
"""
from django.contrib import admin
from django.utils.html import format_html
from igny8_core.admin.base import AccountAdminMixin
from igny8_core.business.billing.models import (
    CreditCostConfig,
    Invoice,
    Payment,
    CreditPackage,
    PaymentMethodConfig,
)
from .models import CreditTransaction, CreditUsageLog, AccountPaymentMethod


@admin.register(CreditTransaction)
class CreditTransactionAdmin(AccountAdminMixin, admin.ModelAdmin):
    list_display = ['id', 'account', 'transaction_type', 'amount', 'balance_after', 'description', 'created_at']
    list_filter = ['transaction_type', 'created_at', 'account']
    search_fields = ['description', 'account__name']
    readonly_fields = ['created_at']
    date_hierarchy = 'created_at'
    
    def get_account_display(self, obj):
        """Safely get account name"""
        try:
            account = getattr(obj, 'account', None)
            return account.name if account else '-'
        except:
            return '-'
    get_account_display.short_description = 'Account'


@admin.register(CreditUsageLog)
class CreditUsageLogAdmin(AccountAdminMixin, admin.ModelAdmin):
    list_display = ['id', 'account', 'operation_type', 'credits_used', 'cost_usd', 'model_used', 'created_at']
    list_filter = ['operation_type', 'created_at', 'account', 'model_used']
    search_fields = ['account__name', 'model_used']
    readonly_fields = ['created_at']
    date_hierarchy = 'created_at'
    
    def get_account_display(self, obj):
        """Safely get account name"""
        try:
            account = getattr(obj, 'account', None)
            return account.name if account else '-'
        except:
            return '-'
    get_account_display.short_description = 'Account'


@admin.register(Invoice)
class InvoiceAdmin(AccountAdminMixin, admin.ModelAdmin):
    list_display = [
        'invoice_number',
        'account',
        'status',
        'total',
        'currency',
        'invoice_date',
        'due_date',
    ]
    list_filter = ['status', 'currency', 'invoice_date', 'account']
    search_fields = ['invoice_number', 'account__name']
    readonly_fields = ['created_at', 'updated_at']


@admin.register(Payment)
class PaymentAdmin(AccountAdminMixin, admin.ModelAdmin):
    """
    Main Payment Admin with approval workflow.
    When you change status to 'succeeded', it automatically:
    - Updates invoice to 'paid'
    - Activates subscription
    - Activates account
    - Adds credits
    """
    list_display = [
        'id',
        'invoice',
        'account',
        'payment_method',
        'status',
        'amount',
        'currency',
        'manual_reference',
        'approved_by',
        'processed_at',
    ]
    list_filter = ['status', 'payment_method', 'currency', 'created_at', 'processed_at']
    search_fields = [
        'invoice__invoice_number', 
        'account__name', 
        'stripe_payment_intent_id', 
        'paypal_order_id',
        'manual_reference',
        'admin_notes',
        'manual_notes'
    ]
    readonly_fields = ['created_at', 'updated_at', 'approved_at', 'processed_at', 'failed_at', 'refunded_at']
    actions = ['approve_payments', 'reject_payments']
    
    fieldsets = (
        ('Payment Info', {
            'fields': ('invoice', 'account', 'amount', 'currency', 'payment_method', 'status')
        }),
        ('Manual Payment Details', {
            'fields': ('manual_reference', 'manual_notes', 'admin_notes'),
            'classes': ('collapse',),
        }),
        ('Stripe/PayPal', {
            'fields': ('stripe_payment_intent_id', 'stripe_charge_id', 'paypal_order_id', 'paypal_capture_id'),
            'classes': ('collapse',),
        }),
        ('Approval Info', {
            'fields': ('approved_by', 'approved_at', 'processed_at', 'failed_at', 'refunded_at', 'failure_reason'),
            'classes': ('collapse',),
        }),
        ('Timestamps', {
            'fields': ('created_at', 'updated_at'),
            'classes': ('collapse',),
        }),
    )
    
    def save_model(self, request, obj, form, change):
        """
        Override save_model to set approved_by when status changes to succeeded.
        The Payment.save() method will handle all the cascade updates automatically.
        """
        if obj.status == 'succeeded' and not obj.approved_by:
            obj.approved_by = request.user
        super().save_model(request, obj, form, change)
    
    def approve_payments(self, request, queryset):
        """Approve selected manual payments"""
        from django.db import transaction
        from django.utils import timezone
        from igny8_core.business.billing.services.credit_service import CreditService
        
        count = 0
        errors = []
        
        for payment in queryset.filter(status='pending_approval'):
            try:
                with transaction.atomic():
                    invoice = payment.invoice
                    subscription = invoice.subscription if hasattr(invoice, 'subscription') else None
                    account = payment.account
                    
                    # Update Payment
                    payment.status = 'succeeded'
                    payment.approved_by = request.user
                    payment.approved_at = timezone.now()
                    payment.processed_at = timezone.now()
                    payment.admin_notes = f'Bulk approved by {request.user.email}'
                    payment.save()
                    
                    # Update Invoice
                    invoice.status = 'paid'
                    invoice.paid_at = timezone.now()
                    invoice.save()
                    
                    # Update Subscription
                    if subscription:
                        subscription.status = 'active'
                        subscription.external_payment_id = payment.manual_reference
                        subscription.save()
                    
                    # Update Account
                    account.status = 'active'
                    account.save()
                    
                    # Add Credits
                    if subscription and subscription.plan:
                        CreditService.add_credits(
                            account=account,
                            amount=subscription.plan.included_credits,
                            transaction_type='subscription',
                            description=f'{subscription.plan.name} - Invoice {invoice.invoice_number}',
                            metadata={
                                'subscription_id': subscription.id,
                                'invoice_id': invoice.id,
                                'payment_id': payment.id,
                                'approved_by': request.user.email
                            }
                        )
                    
                    count += 1
                    
            except Exception as e:
                errors.append(f'Payment {payment.id}: {str(e)}')
        
        if count:
            self.message_user(request, f'Successfully approved {count} payment(s)')
        if errors:
            for error in errors:
                self.message_user(request, error, level='ERROR')
    
    approve_payments.short_description = 'Approve selected manual payments'
    
    def reject_payments(self, request, queryset):
        """Reject selected manual payments"""
        from django.utils import timezone
        
        count = queryset.filter(status='pending_approval').update(
            status='failed',
            approved_by=request.user,
            approved_at=timezone.now(),
            failed_at=timezone.now(),
            admin_notes=f'Bulk rejected by {request.user.email}',
            failure_reason='Rejected by admin'
        )
        
        self.message_user(request, f'Rejected {count} payment(s)')
    
    reject_payments.short_description = 'Reject selected manual payments'


@admin.register(CreditPackage)
class CreditPackageAdmin(admin.ModelAdmin):
    list_display = ['name', 'slug', 'credits', 'price', 'discount_percentage', 'is_active', 'is_featured', 'sort_order']
    list_filter = ['is_active', 'is_featured']
    search_fields = ['name', 'slug']
    readonly_fields = ['created_at', 'updated_at']


@admin.register(PaymentMethodConfig)
class PaymentMethodConfigAdmin(admin.ModelAdmin):
    list_display = ['country_code', 'payment_method', 'display_name', 'is_enabled', 'sort_order', 'updated_at']
    list_filter = ['payment_method', 'is_enabled', 'country_code']
    search_fields = ['country_code', 'display_name', 'payment_method']
    list_editable = ['is_enabled', 'sort_order']
    readonly_fields = ['created_at', 'updated_at']


@admin.register(AccountPaymentMethod)
class AccountPaymentMethodAdmin(AccountAdminMixin, admin.ModelAdmin):
    list_display = [
        'display_name',
        'type',
        'account',
        'is_default',
        'is_enabled',
        'is_verified',
        'country_code',
        'updated_at',
    ]
    list_filter = ['type', 'is_default', 'is_enabled', 'is_verified', 'country_code']
    search_fields = ['display_name', 'account__name', 'account__id']
    readonly_fields = ['created_at', 'updated_at']
    fieldsets = (
        ('Payment Method', {
            'fields': ('account', 'type', 'display_name', 'is_default', 'is_enabled', 'is_verified', 'country_code')
        }),
        ('Instructions / Metadata', {
            'fields': ('instructions', 'metadata')
        }),
        ('Timestamps', {
            'fields': ('created_at', 'updated_at'),
            'classes': ('collapse',)
        }),
    )


@admin.register(CreditCostConfig)
class CreditCostConfigAdmin(admin.ModelAdmin):
    list_display = [
        'operation_type',
        'display_name',
        'credits_cost_display',
        'unit',
        'is_active',
        'cost_change_indicator',
        'updated_at',
        'updated_by'
    ]
    
    list_filter = ['is_active', 'unit', 'updated_at']
    search_fields = ['operation_type', 'display_name', 'description']
    
    fieldsets = (
        ('Operation', {
            'fields': ('operation_type', 'display_name', 'description')
        }),
        ('Cost Configuration', {
            'fields': ('credits_cost', 'unit', 'is_active')
        }),
        ('Audit Trail', {
            'fields': ('previous_cost', 'updated_by', 'created_at', 'updated_at'),
            'classes': ('collapse',)
        }),
    )
    
    readonly_fields = ['created_at', 'updated_at', 'previous_cost']
    
    def credits_cost_display(self, obj):
        """Show cost with color coding"""
        if obj.credits_cost >= 20:
            color = 'red'
        elif obj.credits_cost >= 10:
            color = 'orange'
        else:
            color = 'green'
        return format_html(
            '<span style="color: {}; font-weight: bold;">{} credits</span>',
            color,
            obj.credits_cost
        )
    credits_cost_display.short_description = 'Cost'
    
    def cost_change_indicator(self, obj):
        """Show if cost changed recently"""
        if obj.previous_cost is not None:
            if obj.credits_cost > obj.previous_cost:
                icon = '📈'  # Increased
                color = 'red'
            elif obj.credits_cost < obj.previous_cost:
                icon = '📉'  # Decreased
                color = 'green'
            else:
                icon = '➡️'  # Same
                color = 'gray'
            
            return format_html(
                '{} <span style="color: {};">({} → {})</span>',
                icon,
                color,
                obj.previous_cost,
                obj.credits_cost
            )
        return '—'
    cost_change_indicator.short_description = 'Recent Change'
    
    def save_model(self, request, obj, form, change):
        """Track who made the change"""
        obj.updated_by = request.user
        super().save_model(request, obj, form, change)