"""工作流管理路由。

提供工作流的创建、查询、校验、发布和删除能力。工作流以版本化 DAG 数据保存，
不写死在业务代码中。
"""

from __future__ import annotations

import re
import uuid

from fastapi import APIRouter, Depends, HTTPException

from wov_app.db import Database
from wov_app.schemas import WorkflowCreate
from wov_app.scheduler import topological_sort
from wov_sdk.models import WorkflowDefinition

router = APIRouter(prefix="/api/admin/workflows", tags=["workflows"])


def _get_db() -> Database:
    """从应用状态延迟获取数据库实例。"""
    from wov_app.main import app

    return app.state.db


def _slugify(value: str) -> str:
    """把工作流名称转换为小写连字符 ID；无有效字符时生成随机 ID。"""
    slug = re.sub(r"[^a-z0-9]+", "-", value.lower()).strip("-")
    return slug or uuid.uuid4().hex[:8]


def _validate_definition(raw: dict) -> WorkflowDefinition:
    """解析并校验 DAG 定义，非法时转换为 422 HTTP 异常。

    除 `WorkflowDefinition.validate()` 的结构校验（名称/版本/节点 ID 唯一/
    边引用存在）之外，还要求 DAG **可拓扑排序**：环形依赖结构上合法但无法
    确定执行顺序，必须拒绝保存与发布。
    """
    try:
        definition = WorkflowDefinition.from_dict(raw)
        definition.validate()
        # 环形 DAG（含自环）在这里以 "workflow contains a cycle" 被拒绝。
        topological_sort(definition)
        return definition
    except (KeyError, TypeError, ValueError) as exc:
        raise HTTPException(status_code=422, detail=str(exc)) from exc


@router.get("")
def list_workflows(db: Database = Depends(_get_db)) -> list[dict]:
    """返回全部工作流概要。"""
    return db.list_workflows()


@router.post("")
def create_workflow(
    payload: WorkflowCreate,
    db: Database = Depends(_get_db),
) -> dict:
    """创建新工作流或为已有工作流追加一个版本。"""
    definition = _validate_definition(payload.definition)
    # 未显式指定 ID 时由名称生成；已有工作流则版本号递增。
    workflow_id = payload.id or _slugify(payload.name)
    existing = db.get_workflow(workflow_id)
    version = (existing or {}).get("latest_version", 0) + 1
    # 每次创建都保存新版本，发布操作只切换 published 标记。
    db.upsert_workflow(
        {
            "id": workflow_id,
            "name": payload.name,
            "description": payload.description,
            "published": 0,
            "latest_version": version,
        }
    )
    db.create_workflow_version(workflow_id, version, definition.to_dict())
    return {
        "id": workflow_id,
        "name": payload.name,
        "description": payload.description,
        "published": False,
        "latest_version": version,
    }


@router.get("/{workflow_id}")
def get_workflow(workflow_id: str, db: Database = Depends(_get_db)) -> dict:
    """返回工作流概要及最新版本定义。"""
    workflow = db.get_workflow(workflow_id)
    if workflow is None:
        raise HTTPException(status_code=404, detail="workflow not found")
    latest = db.get_latest_workflow_version(workflow_id)
    workflow["latest_version_data"] = latest
    return workflow


@router.delete("/{workflow_id}")
def delete_workflow(workflow_id: str, db: Database = Depends(_get_db)) -> dict:
    """删除工作流及其版本、任务和产物记录。"""
    if db.get_workflow(workflow_id) is None:
        raise HTTPException(status_code=404, detail="workflow not found")
    db.delete_workflow(workflow_id)
    return {"deleted": workflow_id}


@router.post("/{workflow_id}/validate")
def validate_workflow(
    workflow_id: str,
    definition: dict,
    db: Database = Depends(_get_db),
) -> dict:
    """在不保存的情况下校验一份 DAG 定义。"""
    if db.get_workflow(workflow_id) is None:
        raise HTTPException(status_code=404, detail="workflow not found")
    parsed = _validate_definition(definition)
    return {"valid": True, "node_ids": [node.id for node in parsed.nodes]}


@router.post("/{workflow_id}/publish")
def publish_workflow(workflow_id: str, db: Database = Depends(_get_db)) -> dict:
    """把工作流标记为已发布，使其出现在用户应用中心。"""
    workflow = db.get_workflow(workflow_id)
    if workflow is None:
        raise HTTPException(status_code=404, detail="workflow not found")
    if workflow["latest_version"] == 0:
        raise HTTPException(status_code=422, detail="workflow has no version")
    # 发布前重新校验：无效定义（如环形 DAG）不能进入应用中心，否则任务会在
    # 执行期失败。
    latest = db.get_latest_workflow_version(workflow_id)
    if latest is None:
        raise HTTPException(status_code=422, detail="workflow has no version")
    _validate_definition(latest["definition"])
    # 发布只是状态切换，不修改已保存的版本数据。
    db.upsert_workflow(
        {
            "id": workflow_id,
            "name": workflow["name"],
            "description": workflow["description"],
            "published": 1,
            "latest_version": workflow["latest_version"],
        }
    )
    return {"published": workflow_id}


@router.get("/{workflow_id}/versions")
def list_versions(workflow_id: str, db: Database = Depends(_get_db)) -> list[dict]:
    """返回工作流全部版本定义。"""
    if db.get_workflow(workflow_id) is None:
        raise HTTPException(status_code=404, detail="workflow not found")
    return db.list_workflow_versions(workflow_id)