import uuid

from django.db import models


class Account(models.Model):
    """A node in the chart of accounts (کدینگ حساب‌ها)."""

    ACCOUNT_TYPES = [
        ('asset', 'Asset'),
        ('liability', 'Liability'),
        ('equity', 'Equity'),
        ('income', 'Income'),
        ('expense', 'Expense'),
    ]

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    code = models.CharField(max_length=20, unique=True, db_index=True)
    name = models.CharField(max_length=150)
    type = models.CharField(max_length=20, choices=ACCOUNT_TYPES)
    parent = models.ForeignKey(
        'self', on_delete=models.SET_NULL, null=True, blank=True, related_name='children'
    )
    is_group = models.BooleanField(default=False)
    opening_balance = models.FloatField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'accounting_accounts'
        ordering = ['code']

    def __str__(self):
        return f"{self.code} - {self.name}"


class Party(models.Model):
    """A trading partner (customer or supplier) used by invoices and treasury."""

    PARTY_KINDS = [
        ('customer', 'Customer'),
        ('supplier', 'Supplier'),
    ]

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    kind = models.CharField(max_length=20, choices=PARTY_KINDS)
    name = models.CharField(max_length=150)
    phone = models.CharField(max_length=30, blank=True, default='')
    economic_code = models.CharField(max_length=50, blank=True, default='')
    address = models.TextField(blank=True, default='')
    opening_balance = models.FloatField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'accounting_parties'
        ordering = ['name']

    def __str__(self):
        return self.name


class Product(models.Model):
    """An inventory item."""

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    code = models.CharField(max_length=50, db_index=True)
    name = models.CharField(max_length=150)
    unit = models.CharField(max_length=30, blank=True, default='')
    sale_price = models.FloatField(default=0)
    purchase_price = models.FloatField(default=0)
    stock = models.FloatField(default=0)
    reorder_level = models.FloatField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'accounting_products'
        ordering = ['name']

    def __str__(self):
        return f"{self.code} - {self.name}"


class Voucher(models.Model):
    """A double-entry journal voucher (سند حسابداری)."""

    STATUS_CHOICES = [
        ('draft', 'Draft'),
        ('posted', 'Posted'),
    ]

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    number = models.PositiveIntegerField(default=0)
    date = models.DateField()
    description = models.TextField(blank=True, default='')
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='draft')
    source = models.CharField(max_length=120, blank=True, default='', db_index=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'accounting_vouchers'
        ordering = ['-date', '-number']

    def __str__(self):
        return f"Voucher #{self.number}"


class VoucherLine(models.Model):
    """A single debit/credit line within a voucher."""

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    voucher = models.ForeignKey(Voucher, on_delete=models.CASCADE, related_name='lines')
    account = models.ForeignKey(Account, on_delete=models.PROTECT, related_name='voucher_lines')
    description = models.CharField(max_length=255, blank=True, default='')
    debit = models.FloatField(default=0)
    credit = models.FloatField(default=0)

    class Meta:
        db_table = 'accounting_voucher_lines'

    def __str__(self):
        return f"Line {self.account_id} D:{self.debit} C:{self.credit}"


class Invoice(models.Model):
    """A sales or purchase invoice (فاکتور)."""

    INVOICE_KINDS = [
        ('sale', 'Sale'),
        ('purchase', 'Purchase'),
    ]
    STATUS_CHOICES = [
        ('draft', 'Draft'),
        ('confirmed', 'Confirmed'),
        ('paid', 'Paid'),
    ]

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    kind = models.CharField(max_length=20, choices=INVOICE_KINDS)
    number = models.PositiveIntegerField(default=0)
    party = models.ForeignKey(
        Party, on_delete=models.SET_NULL, null=True, blank=True, related_name='invoices'
    )
    date = models.DateField()
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='draft')
    note = models.TextField(blank=True, default='')
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'accounting_invoices'
        ordering = ['-date', '-number']

    def __str__(self):
        return f"{self.kind} invoice #{self.number}"


class InvoiceLine(models.Model):
    """A line item within an invoice."""

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    invoice = models.ForeignKey(Invoice, on_delete=models.CASCADE, related_name='lines')
    product = models.ForeignKey(
        Product, on_delete=models.PROTECT, null=True, blank=True, related_name='invoice_lines'
    )
    quantity = models.FloatField(default=0)
    unit_price = models.FloatField(default=0)
    discount = models.FloatField(default=0)
    tax_rate = models.FloatField(default=0)

    class Meta:
        db_table = 'accounting_invoice_lines'

    def __str__(self):
        return f"Line {self.product_id} x{self.quantity}"


class TreasuryTxn(models.Model):
    """A treasury receipt or payment (دریافت/پرداخت)."""

    KIND_CHOICES = [
        ('receipt', 'Receipt'),
        ('payment', 'Payment'),
    ]
    METHOD_CHOICES = [
        ('cash', 'Cash'),
        ('bank', 'Bank'),
        ('cheque', 'Cheque'),
    ]

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    number = models.PositiveIntegerField(default=0)
    kind = models.CharField(max_length=20, choices=KIND_CHOICES)
    method = models.CharField(max_length=20, choices=METHOD_CHOICES, default='bank')
    date = models.DateField()
    party = models.ForeignKey(
        Party, on_delete=models.SET_NULL, null=True, blank=True, related_name='treasury_txns'
    )
    amount = models.FloatField(default=0)
    reference = models.CharField(max_length=120, blank=True, default='')
    description = models.TextField(blank=True, default='')
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'accounting_treasury_txns'
        ordering = ['-date', '-number']

    def __str__(self):
        return f"{self.kind} #{self.number}"


class Employee(models.Model):
    """A payroll employee."""

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    code = models.CharField(max_length=50, blank=True, default='')
    name = models.CharField(max_length=150)
    position = models.CharField(max_length=120, blank=True, default='')
    base_salary = models.FloatField(default=0)
    insurance_no = models.CharField(max_length=50, blank=True, default='')
    hire_date = models.DateField(null=True, blank=True)
    active = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'accounting_employees'
        ordering = ['name']

    def __str__(self):
        return self.name


class Payslip(models.Model):
    """A monthly payslip for an employee (فیش حقوقی)."""

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    employee = models.ForeignKey(Employee, on_delete=models.CASCADE, related_name='payslips')
    period = models.CharField(max_length=20, blank=True, default='')
    base_salary = models.FloatField(default=0)
    overtime = models.FloatField(default=0)
    bonus = models.FloatField(default=0)
    deductions = models.FloatField(default=0)
    insurance = models.FloatField(default=0)
    tax = models.FloatField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'accounting_payslips'
        ordering = ['-period']

    def __str__(self):
        return f"Payslip {self.employee_id} - {self.period}"


class CompanySettings(models.Model):
    """Singleton holding company info and the auto-voucher account mapping."""

    id = models.PositiveSmallIntegerField(primary_key=True, default=1)
    name = models.CharField(max_length=150, blank=True, default='')
    economic_code = models.CharField(max_length=50, blank=True, default='')
    fiscal_year = models.CharField(max_length=20, blank=True, default='')
    base_currency = models.CharField(max_length=20, blank=True, default='تومان')
    tax_rate = models.FloatField(default=0)
    address = models.TextField(blank=True, default='')
    phone = models.CharField(max_length=40, blank=True, default='')

    bank_account = models.ForeignKey(
        Account, on_delete=models.SET_NULL, null=True, blank=True, related_name='+'
    )
    owner_payable_account = models.ForeignKey(
        Account, on_delete=models.SET_NULL, null=True, blank=True, related_name='+'
    )
    customer_payable_account = models.ForeignKey(
        Account, on_delete=models.SET_NULL, null=True, blank=True, related_name='+'
    )
    owner_share_account = models.ForeignKey(
        Account, on_delete=models.SET_NULL, null=True, blank=True, related_name='+'
    )
    sales_income_account = models.ForeignKey(
        Account, on_delete=models.SET_NULL, null=True, blank=True, related_name='+'
    )

    class Meta:
        db_table = 'accounting_company_settings'

    def __str__(self):
        return self.name or 'Company Settings'