"""分片上传接口 DTO。"""

from __future__ import annotations

from pydantic import BaseModel, Field


class CreateSessionRequest(BaseModel):
    """创建一个分片上传会话。"""

    filename: str = Field(..., description="客户端原始文件名")
    size_bytes: int = Field(..., ge=0, description="文件总字节数")
    chunk_size: int = Field(..., gt=0, description="分片大小（字节）")
    total_chunks: int = Field(..., gt=0, description="分片总数")


class CreateSessionResponse(BaseModel):
    upload_id: str = Field(..., description="服务端生成的会话标识，后续接口都需要它")
    filename: str
    size_bytes: int
    chunk_size: int
    total_chunks: int


class SessionStatusResponse(BaseModel):
    """会话状态：前端据此决定还需补传哪些分片（断点续传）。"""

    upload_id: str
    filename: str
    size_bytes: int
    chunk_size: int
    total_chunks: int
    uploaded_chunks: list[int] = Field(..., description="已上传的分片下标集合")
    completed: bool = Field(..., description="是否已完成拼接入库")
    file_id: int | None = Field(None, description="completed=true 时指向 UploadedFile.id")


class ChunkUploadResponse(BaseModel):
    """单个分片上传成功的回执。"""

    upload_id: str
    index: int
    uploaded_chunks: list[int]