# -*- coding: utf-8 -*-
from odoo import models, fields, api


class GameRule(models.Model):
    _name = 'game.rule'
    _description = '规则 / 等级制度 / 货币'
    _rec_name = 'name'
    _order = 'category_id, level'

    category_id = fields.Many2one(
        'game.rule.category',
        string='类别',
        required=True,
        index=True,
        ondelete='restrict',
    )
    level = fields.Integer(
        string='等级',
        index=True,
        aggregator=False,  # 分组时不累计
    )
    name = fields.Char(string='名称', required=True)
    desc = fields.Html(string='说明')
    rate = fields.Integer(
        string='兑换比例',
        default=1,
        help='多少单位本货币可兑换 1 单位下一等级货币。例如 100 墟铢 = 1 灵币，则墟铢的 rate 为 100。仅货币类有效。',
    )
    note = fields.Text(
        string='备注',
        help='额外说明，仅后台可见（如发行背景、流通范围等）。',
    )

    @api.model
    def convert(self, amount, from_level, to_level, category_key='currency'):
        """按等级汇率将 amount 从 from_level 换算为 to_level 货币。

        默认只在「货币」类别内换算。汇率方向：低等级 → 高等级 为除以 rate，
        高等级 → 低等级 为乘以 rate。最高等级货币（元玺）的 rate 固定为 1。
        """
        if from_level == to_level:
            return amount
        category = self.env['game.rule.category'].sudo().search(
            [('key', '=', category_key)], limit=1
        )
        if not category:
            return amount
        recs = self.search(
            [('category_id', '=', category.id)],
            order='level asc',
        )
        rate_map = {r.level: r.rate or 1 for r in recs}

        if from_level < to_level:
            result = amount
            for lv in range(from_level, to_level):
                result = result / rate_map.get(lv, 1)
            return result
        else:
            result = amount
            for lv in range(to_level, from_level):
                result = result * rate_map.get(lv, 1)
            return result