import re

with open('expenses/models.py', 'r', encoding='utf-8') as f:
    content = f.read()

# Add TimeStampedModel and CatalogModel right before Project
abstracts = """
from django.core.exceptions import ValidationError

class TimeStampedModel(models.Model):
    created_at = models.DateTimeField(auto_now_add=True, verbose_name="Fecha de Creación")
    updated_at = models.DateTimeField(auto_now=True, verbose_name="Última Modificación")

    class Meta:
        abstract = True

class CatalogModel(TimeStampedModel):
    code = models.CharField(max_length=50, unique=True, verbose_name="Código")
    name = models.CharField(max_length=200, verbose_name="Nombre")
    description = models.TextField(blank=True, verbose_name="Descripción")

    class Meta:
        abstract = True

"""
if 'class TimeStampedModel' not in content:
    content = content.replace("class Project(models.Model):", abstracts + "class Project(CatalogModel):")
    # Clean Project
    content = content.replace("    code = models.CharField(max_length=50, unique=True, verbose_name=\"Código\", default='PROY-000')\n", "")
    content = content.replace("    name = models.CharField(max_length=200, verbose_name=\"Nombre del Proyecto/Centro\")\n", "")
    content = content.replace("    description = models.TextField(blank=True, verbose_name=\"Descripción\")\n", "")
    content = content.replace("    created_at = models.DateTimeField(auto_now_add=True, verbose_name=\"Fecha de Creación\")\n", "")
    content = content.replace("    updated_at = models.DateTimeField(auto_now=True, verbose_name=\"Última Modificación\")\n", "")

    # Clean Category
    content = content.replace("class Category(models.Model):", "class Category(CatalogModel):")
    content = content.replace("    code = models.CharField(max_length=10, unique=True, verbose_name=\"Código de Categoría\")\n", "")
    content = content.replace("    name = models.CharField(max_length=100, verbose_name=\"Nombre de Categoría\")\n", "")
    content = content.replace("    description = models.TextField(blank=True, verbose_name=\"Descripción\")\n", "")

    # Clean Vendor
    content = content.replace("class Vendor(models.Model):", "class Vendor(TimeStampedModel):")
    content = content.replace("    created_at = models.DateTimeField(auto_now_add=True)\n    updated_at = models.DateTimeField(auto_now=True)\n", "")

    # Clean Expense
    content = content.replace("class Expense(models.Model):", "class Expense(TimeStampedModel):")
    # We must only replace the first occurrence of these dates inside Expense, but replace is global.
    # So we do a regex to target Expense block.
    # Actually Expense is the only one with exactly these lines together at the end.
    content = re.sub(r'    created_at = models.DateTimeField\(auto_now_add=True\)\n    updated_at = models.DateTimeField\(auto_now=True\)\n\n    def save', '    def save', content)

encap = """
    def clean(self):
        super().clean()
        if self.amount_clp and self.amount_clp < 0:
            raise ValidationError({'amount_clp': 'El monto neto no puede ser negativo.'})
        
        amount = Decimal(str(self.amount_clp or '0'))
        tax = Decimal(str(self.tax_amount_clp or '0'))
        expected = amount + tax
        
        if self.total_amount_clp and abs(self.total_amount_clp - expected) > Decimal('1.0'):
            raise ValidationError({'total_amount_clp': f'Discrepancia. Total esperado: {expected}'})

    def approve_expense(self, user):
        if self.approval_status == ApprovalStatusEnum.EN_REVISION:
            self.approval_status = ApprovalStatusEnum.SOLICITADO_FINANZAS
            self.elevated_by = user
            self.save()

    def save(self, *args, **kwargs):"""
content = content.replace("    def save(self, *args, **kwargs):", encap)

proxy = """
class Reimbursement(Expense):
    class Meta:
        proxy = True
        verbose_name = "Rendición Especializada"
        verbose_name_plural = "Rendiciones Especializadas"

    def get_approval_flow(self):
        return "Flujo Acelerado de Reembolso"
"""
if 'class Reimbursement' not in content:
    content += proxy

with open('expenses/models.py', 'w', encoding='utf-8') as f:
    f.write(content)