from odoo import fields, models, api


class Textbook(models.Model):
    _name = 'yuthon.school.textbook'
    _description = '教材'
    _order = 'category_id, sequence, name'

    name = fields.Char(
        string='教材名称',
        required=True,
        help='如：Odoo 18 基础入门、Odoo 18 视图开发实战',
    )
    sequence = fields.Integer(
        string='排序',
        default=10,
    )
    category_id = fields.Many2one(
        'yuthon.school.category',
        string='学习分类',
        ondelete='restrict',
        help='该教材所属的学习分类',
    )
    description = fields.Text(
        string='教材简介',
        help='教材的内容概要和适用人群',
    )
    difficulty = fields.Selection(
        [('beginner', '入门'), ('intermediate', '进阶'), ('advanced', '高级')],
        string='难度等级',
        default='beginner',
    )
    state = fields.Selection(
        [('draft', '草稿'), ('published', '已发布')],
        string='状态',
        default='draft',
    )
    total_hours = fields.Float(
        string='总学时',
        compute='_compute_total_hours',
        store=True,
        help='自动统计各章学时之和',
    )
    total_chapters = fields.Integer(
        string='章节数',
        compute='_compute_total_chapters',
        store=True,
    )
    total_videos = fields.Integer(
        string='视频数',
        compute='_compute_total_videos',
        store=True,
    )
    chapter_ids = fields.One2many(
        'yuthon.school.chapter',
        'textbook_id',
        string='章节',
    )
    active = fields.Boolean(
        string='启用',
        default=True,
    )

    @api.depends('chapter_ids.hours')
    def _compute_total_hours(self):
        for record in self:
            record.total_hours = sum(record.chapter_ids.mapped('hours'))

    @api.depends('chapter_ids')
    def _compute_total_chapters(self):
        for record in self:
            record.total_chapters = len(record.chapter_ids)

    @api.depends('chapter_ids.video_ids')
    def _compute_total_videos(self):
        for record in self:
            record.total_videos = sum(len(ch.video_ids) for ch in record.chapter_ids)

    def action_confirm(self):
        """发布教材：将状态从草稿改为已发布"""
        self.write({'state': 'published'})

    def action_set_draft(self):
        """退回草稿：将状态从已发布改回草稿"""
        self.write({'state': 'draft'})


class Chapter(models.Model):
    _name = 'yuthon.school.chapter'
    _description = '章节'
    _order = 'textbook_id, sequence, name'

    _sql_constraints = [
        ('unique_chapter_seq',
         'unique(textbook_id, sequence)',
         '同一教材下章节序号不能重复！'),
    ]

    name = fields.Char(
        string='章节标题',
        required=True,
    )
    sequence = fields.Integer(
        string='排序',
        default=10,
    )
    textbook_id = fields.Many2one(
        'yuthon.school.textbook',
        string='所属教材',
        required=True,
        ondelete='cascade',
    )
    summary = fields.Text(
        string='内容概述',
        help='本章涵盖的内容概述',
    )
    key_points = fields.Text(
        string='知识要点',
        help='本章需要掌握的关键知识点',
    )
    hours = fields.Float(
        string='学时',
        default=1.0,
        help='本章预计学习时长（小时）',
    )
    video_ids = fields.One2many(
        'yuthon.school.video',
        'chapter_id',
        string='视频',
    )
    video_count = fields.Integer(
        string='视频数',
        compute='_compute_video_count',
        store=True,
    )

    @api.depends('video_ids')
    def _compute_video_count(self):
        for record in self:
            record.video_count = len(record.video_ids)

    @api.onchange('video_ids')
    def _onchange_video_ids(self):
        """当视频列表变化时，自动建议学时（每个视频按 0.5 学时计算）"""
        if self.video_ids:
            suggested = max(1.0, len(self.video_ids) * 0.5)
            self.hours = suggested