from odoo import models, fields
from dateutil.relativedelta import relativedelta


class LoanRepaymentPreviewWizard(models.TransientModel):
    _name = 'loan.repayment.preview.wizard'
    _description = 'Loan Repayment Preview Wizard'

    loan_request_id = fields.Many2one('loan.request', string='Yêu cầu vay', required=True)
    preview_line_ids = fields.One2many('loan.repayment.preview.line', 'wizard_id', string='Chi tiết lịch trả', readonly=True)

    def action_generate_preview_schedule(self):
        self.ensure_one()
        request = self.loan_request_id
        self.preview_line_ids.unlink()  # Clear old preview lines

        amount = request.amount
        term = request.term
        rate = request.interest_rate
        repayment_type = request.repayment_type
        start_date = request.request_datetime.date() or fields.Date.today()

        for i in range(term):
            due_date = start_date + relativedelta(months=i + 1)

            if repayment_type == 'fixed_principal':
                principal = amount / term
                interest = (amount - principal * i) * rate / 100 / 12
                total = principal + interest

            elif repayment_type == 'annuity':
                monthly_rate = rate / 100 / 12
                if monthly_rate == 0:
                    annuity = amount / term
                else:
                    annuity = (amount * monthly_rate) / (1 - (1 + monthly_rate) ** -term)
                interest = (amount - i * (amount / term)) * monthly_rate
                principal = annuity - interest
                total = annuity

            elif repayment_type == 'interest_only':
                principal = amount if i == term - 1 else 0
                interest = amount * rate / 100 / 12
                total = principal + interest

            elif repayment_type == 'lump_sum':
                principal = amount if i == term - 1 else 0
                interest = amount * rate / 100 / 12
                total = principal + interest

            self.env['loan.repayment.preview.line'].create({
                'wizard_id': self.id,
                'installment': i + 1,
                'due_date': due_date,
                'principal': round(principal, 2),
                'interest': round(interest, 2),
                'total': round(total, 2),
            })