from django.db import models


class UploadedDocument(models.Model):
    """
    保存用户上传文档的元数据和入库状态。

    设计上只记录“文件属于哪个场景、当前是否已入库、失败原因是什么”，
    不把 RAG 细节耦合进模型层。
    """
    # 文档状态用于驱动前端提示和后续可操作项。
    STATUS_UPLOADED = "uploaded"
    STATUS_INDEXED = "indexed"
    STATUS_FAILED = "failed"

    scenario_id = models.CharField(max_length=100, db_index=True)
    original_name = models.CharField(max_length=255)
    file = models.FileField(upload_to="documents/%Y%m%d/")
    file_type = models.CharField(max_length=20)
    size = models.PositiveIntegerField(default=0)
    status = models.CharField(max_length=20, default=STATUS_UPLOADED, db_index=True)
    error_message = models.TextField(blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ["-created_at"]

    def __str__(self) -> str:
        return self.original_name

    def get_status_display_text(self) -> str:
        """为模板提供更适合演示的中文状态文案。"""
        return {
            self.STATUS_UPLOADED: "已上传，待入库",
            self.STATUS_INDEXED: "已入库，可检索",
            self.STATUS_FAILED: "入库失败",
        }.get(self.status, self.status)