from odoo import api, fields, models
from odoo.tools import human_size
import base64
import os


class CourseSyllabus(models.Model):
    _name = 'course.syllabus'
    _description = '教学大纲/教案'
    _rec_name = 'title'
    _order = 'course_id, syllabus_type, version desc'
    _inherit = ['mail.thread']

    title = fields.Char(string='标题', required=True)
    syllabus_type = fields.Selection([
        ('syllabus', '教学大纲'),
        ('lesson_plan', '教案'),
    ], string='类型', required=True)
    course_id = fields.Many2one('learning.course', string='所属课程', required=True, ondelete='cascade')
    course_name = fields.Char(related="course_id.name", string="课程名称", readonly=True)
    course_code = fields.Char(related="course_id.code", string="课程代码", readonly=True)
    course_credit = fields.Float(related="course_id.credit", string="学分", readonly=True)
    course_exam_type = fields.Selection(related="course_id.exam_type", string="考核方式", readonly=True)
    chapter_id = fields.Many2one('course.chapter', string='关联章节')
    chapter_name = fields.Char(related="chapter_id.name", string="章节名称", readonly=True)
    chapter_sequence = fields.Integer(related="chapter_id.sequence", string="章节序号", readonly=True)
    chapter_is_published = fields.Boolean(related="chapter_id.is_published", string="发布状态", readonly=True)

    # 文件核心字段
    file = fields.Binary(string='文件', attachment=True, required=True)
    file_name = fields.Char(string='文件名')
    file_size = fields.Integer(string='文件大小(字节)', readonly=True)
    file_size_str = fields.Char(string='文件大小', readonly=True)  # 友好显示：KB/MB
    file_suffix = fields.Char(string='文件格式', readonly=True)  # 后缀：docx/pptx/pdf

    version = fields.Char(string='版本号', default='1.0')
    version_note = fields.Char(string='版本说明')
    publish_date = fields.Date(string='发布日期', default=fields.Date.today)
    is_published = fields.Boolean(string='是否发布', default=True)
    download_count = fields.Integer(string='下载次数', default=0)
    teaching_class_id = fields.Many2one(
        'course.teaching_class',
        string='教学班',
        ondelete='cascade',
        domain="[('course_id', '=', course_id)]"
    )

    # 监听文件上传，自动赋值文件名、大小、后缀
    @api.onchange('file', 'file_name')
    def _onchange_file_upload(self):
        for record in self:
            if record.file and record.file_name:
                # 计算文件大小（base64 换算）
                file_data = base64.b64decode(record.file)
                size_bytes = len(file_data)
                record.file_size = size_bytes
                record.file_size_str = human_size(size_bytes)

                # 提取文件后缀
                name, suffix = os.path.splitext(record.file_name)
                record.file_suffix = suffix.lower().strip('.')
            else:
                record.file_size = 0
                record.file_size_str = ''
                record.file_suffix = ''

    # 修复批量下载问题 + 优化下载响应
    def action_download(self):
        for rec in self:
            rec.download_count += 1
            if rec.file_name:
                # 携带真实文件名，浏览器正常识别
                url = f'/web/content/course.syllabus/{rec.id}/file/{rec.file_name}?download=true'
            else:
                url = f'/web/content/course.syllabus/{rec.id}/file?download=true'
        return {
            'type': 'ir.actions.act_url',
            'url': url,
            'target': 'self',  # self 强制下载，new 新标签页打开
        }