from odoo import fields, models, api


class Course(models.Model):
    _name = 'yuthon.school.course'
    _description = '课程'
    _order = 'sequence, name'

    name = fields.Char(
        string='课程名称',
        required=True,
        help='如：Odoo 18 全栈开发工程师认证课程',
    )
    code = fields.Char(
        string='课程编号',
        help='如：ODOO-101',
    )
    sequence = fields.Integer(
        string='排序',
        default=10,
    )
    category_id = fields.Many2one(
        'yuthon.school.category',
        string='学习分类',
        ondelete='restrict',
    )
    teacher_id = fields.Many2one(
        'yuthon.school.teacher',
        string='授课教师',
    )
    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'), ('recruiting', '招生中'),
         ('ongoing', '进行中'), ('finished', '已结课')],
        string='状态',
        default='draft',
    )
    description = fields.Text(
        string='课程简介',
        help='课程目标、适合人群、考核方式等',
    )
    textbook_ids = fields.Many2many(
        'yuthon.school.textbook',
        'yuthon_course_textbook_rel',
        'course_id', 'textbook_id',
        string='关联教材',
        help='本课程涵盖的教材（Many2many 演示）',
    )
    syllabus_ids = fields.One2many(
        'yuthon.school.syllabus',
        'course_id',
        string='课程大纲',
    )
    student_ids = fields.Many2many(
        'yuthon.school.student',
        'yuthon_course_student_rel',
        'course_id', 'student_id',
        string='选课学生',
        help='选修本课程的学生（Many2many 演示）',
    )
    total_hours = fields.Float(
        string='总学时',
        compute='_compute_total_hours',
        store=True,
        help='自动汇总关联教材各章学时',
    )
    enrollment_count = fields.Integer(
        string='选课人数',
        compute='_compute_counts',
        store=True,
    )
    syllabus_count = fields.Integer(
        string='大纲条目',
        compute='_compute_counts',
        store=True,
    )
    active = fields.Boolean(
        string='启用',
        default=True,
    )

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

    @api.depends('student_ids', 'syllabus_ids')
    def _compute_counts(self):
        for record in self:
            record.enrollment_count = len(record.student_ids)
            record.syllabus_count = len(record.syllabus_ids)

    def action_recruit(self):
        """开始招生"""
        self.write({'state': 'recruiting'})

    def action_start(self):
        """开课"""
        self.write({'state': 'ongoing'})

    def action_finish(self):
        """结课"""
        self.write({'state': 'finished'})