"""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 json
import shutil
import uuid
from datetime import datetime, timezone
from pathlib import Path

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

from wov_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 wov_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(...),
    params: str = Form(default=""),
    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 wov_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)

    # 可选参数覆盖（如前端框选的 crop）：{节点ID: {参数: 值}}，随任务持久化。
    param_overrides = None
    if params.strip():
        try:
            parsed = json.loads(params)
        except json.JSONDecodeError as exc:
            raise HTTPException(status_code=422, detail="params must be valid JSON") from exc
        if not isinstance(parsed, dict):
            raise HTTPException(status_code=422, detail="params must be a JSON object")
        param_overrides = parsed

    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),
            "param_overrides": param_overrides,
            "created_at": now,
            "updated_at": now,
        }
    )
    return {
        "id": run_id,
        "status": "QUEUED",
        "progress": 0,
        "artifacts": [],
    }


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

    默认排除批量 run（每个批量任务会产生 N 条单视频 run，属于批量页的明细，
    混进来会把列表占满）；`?include_batch=1` 可包含它们供排查。
    """
    return db.list_runs(include_batch=include_batch)


@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())
    # 重试前清除可能残留的暂停信号（任务失败时信号文件可能仍在）。
    from wov_app.config import STORAGE_DIR

    (STORAGE_DIR / "runs" / run_id / "paused.flag").unlink(missing_ok=True)
    return {"id": run_id, "status": "QUEUED"}


@router.post("/api/runs/{run_id}/pause")
def pause_run(run_id: str, db: Database = Depends(_get_db)) -> dict:
    """暂停任务：排队中或运行中的任务可暂停，运行中的任务在节点边界停下。"""
    run = db.get_run(run_id)
    if run is None:
        raise HTTPException(status_code=404, detail="run not found")
    if run["status"] not in ("QUEUED", "RUNNING"):
        raise HTTPException(status_code=422, detail="only queued or running runs can be paused")
    db.pause_run(run_id, _now_iso())
    # 写入暂停信号文件：运行中的节点（如 OCR）逐帧检查到后立即中止，
    # 由调度器保持 PAUSED；resume 时清除。
    from wov_app.config import STORAGE_DIR

    run_dir = STORAGE_DIR / "runs" / run_id
    run_dir.mkdir(parents=True, exist_ok=True)
    (run_dir / "paused.flag").write_text("", encoding="utf-8")
    return {"id": run_id, "status": "PAUSED"}


@router.post("/api/runs/{run_id}/resume")
def resume_run(run_id: str, db: Database = Depends(_get_db)) -> dict:
    """继续任务：暂停的任务恢复排队，由调度器从断点继续执行。"""
    run = db.get_run(run_id)
    if run is None:
        raise HTTPException(status_code=404, detail="run not found")
    if run["status"] != "PAUSED":
        raise HTTPException(status_code=422, detail="only paused runs can be resumed")
    db.resume_run(run_id, _now_iso())
    # 清除暂停信号文件，避免节点误判仍处于暂停状态。
    from wov_app.config import STORAGE_DIR

    (STORAGE_DIR / "runs" / run_id / "paused.flag").unlink(missing_ok=True)
    return {"id": run_id, "status": "QUEUED"}

@router.delete("/api/runs/{run_id}")
def delete_run(run_id: str, db: Database = Depends(_get_db)) -> dict:
    """删除上传任务及其私有文件；批量 run 必须通过批量任务入口删除。"""
    run = db.get_run(run_id)
    if run is None:
        raise HTTPException(status_code=404, detail="run not found")
    # 批量 run 的输入是用户原始视频，且由 batch_videos 关联管理。
    # 在任何数据库/文件删除之前拒绝，避免误删媒体库或留下悬空的批量明细。
    if run.get("source") == "batch":
        raise HTTPException(status_code=422, detail="请通过批量任务入口删除该任务")
    from wov_app.config import STORAGE_DIR

    # 先删数据库记录（含产物表），再清理磁盘上的上传与中间产物。
    db.delete_run(run_id)
    # 删除范围仅来自该任务的私有存储布局，绝不由 input_uri 推导：
    # 即使历史上传记录引用外部路径，也必须保留源视频和同目录的用户文件。
    shutil.rmtree(STORAGE_DIR / "uploads" / run_id, ignore_errors=True)
    # 步骤产物位于 <storage>/runs/<run_id>/，整目录一并删除。
    shutil.rmtree(STORAGE_DIR / "runs" / run_id, ignore_errors=True)
    return {"deleted": run_id}

@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,
    )