# -*- coding: utf-8 -*-

from odoo import models, api, _
from odoo.exceptions import UserError
from odoo.tools.float_utils import float_round
from odoo.fields import Command
import random

def _generate_random_reward_code():
    return f"REWARD-{random.randint(100000, 999999)}"

class SaleOrder(models.Model):
    _inherit = 'sale.order'

    def _get_cheapest_matching_product(self, reward):
        self.ensure_one()
        candidate_lines = self.order_line.filtered(
            lambda l: not l.is_reward_line and l.product_uom_qty > 0 and l.price_unit > 0
        )
        if reward.reward_product_id or reward.reward_product_tag_id or reward.reward_product_category_id:
            allowed_products = reward.reward_product_id
            if reward.reward_product_tag_id:
                allowed_products |= reward.reward_product_tag_id.product_ids
            
            category_ids = []
            if reward.reward_product_category_id:
                category_ids = self.env['product.category'].search([
                    ('id', 'child_of', reward.reward_product_category_id.ids)
                ]).ids
            
            candidate_lines = candidate_lines.filtered(
                lambda l: l.product_id in allowed_products or (
                    category_ids and l.product_id.categ_id.id in category_ids
                )
            )
        if not candidate_lines:
            return None
        cheapest_line = min(candidate_lines, key=lambda l: l.price_unit)
        return cheapest_line.product_id

    def _get_reward_values_product(self, reward, coupon, product=None, **kwargs):
        self.ensure_one()
        if reward.reward_product_applicability != 'cheapest':
            return super()._get_reward_values_product(reward, coupon, product=product, **kwargs)

        # Cheapest product applicability logic
        if not product:
            product = self._get_cheapest_matching_product(reward)
        if not product:
            # Fallback if no eligible product in cart
            allowed_products = reward.reward_product_id
            if reward.reward_product_tag_id:
                allowed_products |= reward.reward_product_tag_id.product_ids
            if reward.reward_product_category_id:
                category_ids = self.env['product.category'].search([
                    ('id', 'child_of', reward.reward_product_category_id.ids)
                ]).ids
                allowed_products |= self.env['product.product'].search([
                    ('categ_id', 'in', category_ids),
                    ('type', '!=', 'combo')
                ], limit=1)
            
            if allowed_products:
                product = allowed_products[:1]
            else:
                first_line = self.order_line.filtered(lambda l: not l.is_reward_line and l.product_uom_qty > 0)[:1]
                product = first_line.product_id

        if not product:
            raise UserError(_("No eligible product in the cart to apply the cheapest product reward."))

        # Compute reward values directly to support global cheapest reward
        taxes = self.fiscal_position_id.map_tax(product.taxes_id._filter_taxes_by_company(self.company_id))
        points = self._get_real_points_for_coupon(coupon)
        claimable_count = float_round(points / reward.required_points, precision_rounding=1, rounding_method='DOWN') if not reward.clear_wallet else 1
        cost = points if reward.clear_wallet else claimable_count * reward.required_points
        
        return [{
            'name': reward.description or _("Free Product (Cheapest)"),
            'product_id': product.id,
            'discount': 100,
            'product_uom_qty': reward.reward_product_qty * claimable_count,
            'reward_id': reward.id,
            'coupon_id': coupon.id,
            'points_cost': cost,
            'reward_identifier_code': _generate_random_reward_code(),
            'sequence': max(self.order_line.filtered(lambda x: not x.is_reward_line).mapped('sequence'), default=10) + 1,
            'tax_ids': [Command.clear()] + [Command.link(tax.id) for tax in taxes],
        }]