"""用户端应用路由。

面向普通用户暴露“应用中心”能力：列出已发布工作流、上传输入创建任务、
查询进度、重试失败任务以及下载产物。用户只看到输入 -> 进度 -> 结果。
"""

from __future__ import annotations

import uuid
from datetime import datetime, timezone
from pathlib import Path

from fastapi import APIRouter, Depends, File, HTTPException, UploadFile
from fastapi.responses import FileResponse

from app.db import Database

router = APIRouter(tags=["apps"])


def _now_iso() -> str:
    """返回当前 UTC 时间的 ISO 格式字符串。"""
    return datetime.now(timezone.utc).isoformat()


def _get_db() -> Database:
    """从 FastAPI 应用状态中延迟获取数据库实例。"""
    from app.main import app

    return app.state.db


@router.get("/api/apps")
def list_apps(db: Database = Depends(_get_db)) -> list[dict]:
    """返回全部已发布工作流及其最新版本定义。"""
    apps = []
    for workflow in db.list_workflows():
        # 草稿工作流不对用户端可见。
        if not workflow["published"]:
            continue
        latest = db.get_latest_workflow_version(workflow["id"])
        apps.append(
            {
                "id": workflow["id"],
                "name": workflow["name"],
                "description": workflow["description"],
                "version": workflow["latest_version"],
                "definition": latest["definition"] if latest else None,
            }
        )
    return apps


@router.post("/api/apps/{workflow_id}/runs")
async def create_run(
    workflow_id: str,
    file: UploadFile = File(...),
    db: Database = Depends(_get_db),
) -> dict:
    """接收用户上传文件，创建排队中的工作流任务。"""
    workflow = db.get_workflow(workflow_id)
    # 只允许对已发布且存在版本的工作流发起任务。
    if workflow is None or not workflow["published"]:
        raise HTTPException(status_code=404, detail="published workflow not found")

    latest = db.get_latest_workflow_version(workflow_id)
    if latest is None:
        raise HTTPException(status_code=422, detail="workflow has no version")

    run_id = f"run_{uuid.uuid4().hex[:12]}"
    # 使用安全文件名，避免路径穿越。
    filename = Path(file.filename or "upload.bin").name
    from app.config import STORAGE_DIR

    # 上传文件按 run 隔离存放，调度器通过 input_uri 引用。
    input_dir = STORAGE_DIR / "uploads" / run_id
    input_dir.mkdir(parents=True, exist_ok=True)
    input_uri = input_dir / filename
    content = await file.read()
    input_uri.write_bytes(content)

    now = _now_iso()
    db.create_run(
        {
            "id": run_id,
            "workflow_id": workflow_id,
            "workflow_version": latest["version"],
            "status": "QUEUED",
            "progress": 0,
            "input_uri": str(input_uri),
            "created_at": now,
            "updated_at": now,
        }
    )
    return {
        "id": run_id,
        "status": "QUEUED",
        "progress": 0,
        "artifacts": [],
    }


@router.get("/api/runs")
def list_runs(db: Database = Depends(_get_db)) -> list[dict]:
    """返回最近的运行记录，供任务管理页展示。"""
    return db.list_runs()


@router.get("/api/runs/{run_id}")
def get_run(run_id: str, db: Database = Depends(_get_db)) -> dict:
    """返回任务详情，并附带当前产物列表。"""
    run = db.get_run(run_id)
    if run is None:
        raise HTTPException(status_code=404, detail="run not found")
    run["artifacts"] = db.list_artifacts(run_id)
    return run


@router.post("/api/runs/{run_id}/retry")
def retry_run(run_id: str, db: Database = Depends(_get_db)) -> dict:
    """重置失败任务为排队状态，清空旧产物后重新执行。"""
    run = db.get_run(run_id)
    if run is None:
        raise HTTPException(status_code=404, detail="run not found")
    if run["status"] != "FAILED":
        raise HTTPException(status_code=422, detail="only failed runs can be retried")
    # reset_run 会清空进度、错误和旧产物，确保从头开始。
    db.reset_run(run_id, _now_iso())
    return {"id": run_id, "status": "QUEUED"}


@router.get("/api/runs/{run_id}/artifacts")
def list_run_artifacts(run_id: str, db: Database = Depends(_get_db)) -> list[dict]:
    """返回任务全部产物记录。"""
    if db.get_run(run_id) is None:
        raise HTTPException(status_code=404, detail="run not found")
    return db.list_artifacts(run_id)


@router.get("/api/runs/{run_id}/artifacts/{artifact_name}")
def download_artifact(
    run_id: str,
    artifact_name: str,
    db: Database = Depends(_get_db),
) -> FileResponse:
    """按任务与产物名下载文件，文件缺失时返回 404。"""
    artifact = db.get_artifact(run_id, artifact_name)
    if artifact is None:
        raise HTTPException(status_code=404, detail="artifact not found")
    path = Path(artifact["uri"])
    if not path.is_file():
        raise HTTPException(status_code=404, detail="artifact file missing")
    return FileResponse(
        path,
        media_type=artifact["mime_type"],
        filename=path.name,
    )