from django.db import models
from django.db.models import Count

from university.db.fields import JSONField


class OnlineExam(models.Model):

    FLAG_PCTA = 'PCTA'
    FLAG_PCTP = 'PCTP'
    FLAG_CHOICES = (
        (FLAG_PCTA, 'PCTA'),
        (FLAG_PCTP, 'PCTP')
    )

    name = models.CharField(max_length=255)
    slug = models.SlugField(blank=False, null=False, allow_unicode=True)
    flag = models.CharField(
        max_length=32, default=FLAG_PCTA, choices=FLAG_CHOICES)
    cover_image = models.ForeignKey('university.Upload', on_delete=models.PROTECT)
    short_description = models.CharField(max_length=255)
    detailed_description = models.TextField()
    rules = models.TextField()
    registration_deadline = models.DateTimeField(blank=False, null=False)
    start_at = models.DateTimeField(blank=False, null=False)
    end_at = models.DateTimeField(blank=False, null=False)
    total_score = models.IntegerField(default=0)
    passing_score = models.IntegerField(default=0)
    number_of_questions = models.IntegerField(default=0)
    answers = JSONField(default={})
    structure = JSONField(default=[])
    allowed_cheating_times = models.IntegerField(default=4)
    alert_wechat_webhook = models.URLField(blank=True, null=True)
    ip_allowlist = JSONField(default=[])
    # [{
    #     "title": "一、单选题",
    #     "description": "",
    #     "number_of_questions": 10,
    #     "questions": [{
    #         "id": "Q_1", // 试题 ID
    #         "type": 0,  // 试题类型: 0 -> 单选题,  1 -> 多选题
    #         "score": 1,  // 分数
    #         "problem": "关于TiDB 的索引 Key 编码，下列哪一项是对的？",  // 问题
    #         "options": [
    #             {
    #                 "value": "O_1",
    #                 "text": "需要 Mem compareble 的编码算法"
    #             },
    #             {
    #                 "value": "O_2",
    #                 "text": "索引 Key 中一定包含 RowID"
    #             },
    #             {
    #                 "value": "O_3",
    #                 "text": "TiDB 支持对索引 Key 进行逆序编码，以支持逆序索引"
    #             }
    #         ]
    #     }, {
    #         "title": "二、多选题",
    #         "description": "",
    #         "number_of_questions": 20,
    #         "questions": [{
    #             "id": "Q_2", // 试题 ID
    #             "type": 1,  // 试题类型: 0 -> 单选题,  1 -> 多选题
    #             "score": 1,  // 分数
    #             "problem": "TiDB 集群建议使用的 Linux 操作系统是？",  // 问题
    #             "options": [
    #                 {
    #                     "value": "O_12",
    #                     "text": "Red Hat Enterprise Linux"
    #                 },
    #                 {
    #                     "value": "O_2",
    #                     "text": "CentOS"
    #                 },
    #                 {
    #                     "value": "O_3",
    #                     "text": "Debian Linux"
    #                 }
    #             ]
    #         }]
    #     }],
    #     "draft": {          // 草稿, 恢复用户之前已完成的答案
    #         "Q_1": "O_1",   // Key 为试题 ID, value 为答案
    #         "Q_2": "O_1",   // 单选题答案
    #         "Q_3": ["O_1", "O_2"],  // 多选题答案
    #     }
    # }]

    class Meta:
        db_table = 'online_exams'

    def get_status_distribution(self):
        from university.models import UserOnlineExam

        data = list(self.useronlineexam_set.all().values('status').annotate(count=Count('status')))
        for d in data:
            d['status_display'] = dict(UserOnlineExam.STATUS_CHOICES).get(d['status'], '未知状态')
        return data