from odoo import models, fields, api
from odoo.exceptions import UserError


class LinkAdvancePaymentWizard(models.TransientModel):
    _name = 'link.advance.payment.wizard'
    _description = 'Link Advance Payment Wizard'

    purchase_order_id = fields.Many2one(
        'purchase.order',
        string='Purchase Order'
    )
    
    payment_id = fields.Many2one(
        'account.payment',
        string='Payment',
        domain=[('state', '=', 'draft')]
    )
    
    amount = fields.Monetary(
        string='Amount'
    )
    
    currency_id = fields.Many2one(
        'res.currency',
        string='Currency'
    )

    @api.model
    def default_get(self, fields):
        res = super().default_get(fields)
        # Handle context from purchase order
        if self._context.get('active_model') == 'purchase.order' and self._context.get('active_id'):
            po = self.env['purchase.order'].browse(self._context['active_id'])
            res['purchase_order_id'] = po.id
            res['currency_id'] = po.currency_id.id
            if 'amount' in fields:
                res['amount'] = po.amount_residual
        # Handle context from payment
        elif self._context.get('active_model') == 'account.payment' and self._context.get('active_id'):
            payment = self.env['account.payment'].browse(self._context['active_id'])
            res['payment_id'] = payment.id
            res['currency_id'] = payment.currency_id.id
            if 'amount' in fields:
                res['amount'] = payment.amount
        return res

    @api.onchange('payment_id')
    def _onchange_payment_id(self):
        if self.payment_id:
            self.currency_id = self.payment_id.currency_id.id
            self.amount = self.payment_id.amount
            
            # Filter purchase orders by partner when payment is selected
            if self.payment_id.partner_id:
                purchase_orders = self.env['purchase.order'].search([
                    ('partner_id', '=', self.payment_id.partner_id.id),
                    ('state', 'in', ['purchase', 'done'])
                ])
                return {'domain': {'purchase_order_id': [('id', 'in', purchase_orders.ids)]}}
        return {'domain': {'purchase_order_id': []}}

    @api.onchange('purchase_order_id')
    def _onchange_purchase_order_id(self):
        if self.purchase_order_id:
            self.currency_id = self.purchase_order_id.currency_id.id
            self.amount = self.purchase_order_id.amount_residual
            
            # Filter payments by partner when purchase order is selected
            if self.purchase_order_id.partner_id:
                payments = self.env['account.payment'].search([
                    ('partner_id', '=', self.purchase_order_id.partner_id.id),
                    ('state', '=', 'draft'),
                    ('payment_type', '=', 'outbound')
                ])
                return {'domain': {'payment_id': [('id', 'in', payments.ids)]}}
        return {'domain': {'payment_id': []}}

    def action_link_payment(self):
        self.ensure_one()
        if self.amount <= 0:
            raise UserError("Amount must be greater than zero.")
            
        # Check if we have both payment and purchase order
        if not self.payment_id:
            raise UserError("Payment must be specified.")
            
        if not self.purchase_order_id:
            raise UserError("Purchase order must be specified.")
            
        # Link the payment to the purchase order
        self.payment_id.write({
            'purchase_order_id': self.purchase_order_id.id,
            'is_advance_payment': True,
            'amount': self.amount
        })
            
        return {
            'type': 'ir.actions.act_window_close'
        }