from types import SimpleNamespace
from typing import Any

from fastapi import FastAPI, HTTPException
from pydantic import BaseModel, ValidationError
from sqlalchemy import select

from plugins.core.runtime.health import PluginHealthContext
from plugins.core.sdk import PluginDefinition, PluginHostContext, PluginRequestContext
from plugins.core.sdk.asgi import plugin_endpoint

from . import service
from .models import TaskIdentifier, TaskInput, TaskQuery, tasks

VERSION = '1.1.0'
_runtime = SimpleNamespace(session_factory=None)


def _validate(model: type[BaseModel], values: dict[str, Any]) -> Any:
    """
    校验 SDK 请求快照中的路径和查询参数。

    :param model: 目标参数模型
    :param values: 原始参数字段
    :return: 已校验的模型；无效输入返回 HTTP 422
    """
    try:
        return model.model_validate(values)
    except ValidationError as exc:
        raise HTTPException(
            status_code=422,
            detail=exc.errors(include_input=False, include_context=False, include_url=False),
        ) from exc


def _task_id(context: PluginRequestContext) -> str:
    """
    读取 SDK 已提取的任务路径参数。

    :param context: 含 HTTP 请求快照的宿主上下文
    :return: 已校验的任务标识
    """
    return _validate(TaskIdentifier, {'id': context.request.path_params['task_id']}).id


async def info(context: PluginRequestContext) -> dict[str, Any]:
    return {'pluginId': context.host.plugin_id, 'version': VERSION, 'canWrite': service.can_write(context)}


async def list_tasks(context: PluginRequestContext) -> dict[str, Any]:
    if any(len(values) != 1 for values in context.request.query.values()):
        raise HTTPException(status_code=422, detail='查询参数不能重复')
    query = _validate(TaskQuery, {key: values[0] for key, values in context.request.query.items()})
    return await service.list_tasks(context, query)


async def get_task(context: PluginRequestContext) -> dict[str, Any]:
    return await service.get_task(context, _task_id(context))


async def create_task(context: PluginRequestContext) -> dict[str, Any]:
    return await service.create_task(context, context.request.body)


async def update_task(context: PluginRequestContext) -> dict[str, Any]:
    return await service.update_task(context, _task_id(context), context.request.body)


async def delete_task(context: PluginRequestContext) -> dict[str, bool]:
    return await service.delete_task(context, _task_id(context))


def create_plugin(host: PluginHostContext) -> PluginDefinition:
    """
    声明使用宿主事务能力的任务插件，不在启动时创建表。

    :param host: 宿主提供的插件能力
    :return: 仅挂载相对 API 的 ASGI 插件声明
    """
    # 仅保存宿主授予的会话工厂，健康检查自行开关会话，不保留请求会话。
    _runtime.session_factory = host.session_factory

    def create_app(context: PluginHostContext) -> FastAPI:
        """
        创建任务管理子应用，各接口独立声明读写权限。

        :param context: 宿主提供的插件能力
        :return: 任务管理 ASGI 子应用
        """
        app = FastAPI(title='持久化任务示例', docs_url=None, redoc_url=None, openapi_url=None)
        app.add_api_route('/api/info', plugin_endpoint(info, permission='task_demo:view'), methods=['GET'])
        app.add_api_route('/api/tasks', plugin_endpoint(list_tasks, permission='task_demo:view'), methods=['GET'])
        app.add_api_route(
            '/api/tasks/{task_id}', plugin_endpoint(get_task, permission='task_demo:view'), methods=['GET']
        )
        app.add_api_route(
            '/api/tasks',
            plugin_endpoint(create_task, permission='task_demo:write', body_model=TaskInput, max_body_bytes=8192),
            methods=['POST'],
            status_code=201,
        )
        app.add_api_route(
            '/api/tasks/{task_id}',
            plugin_endpoint(update_task, permission='task_demo:write', body_model=TaskInput, max_body_bytes=8192),
            methods=['PUT'],
        )
        app.add_api_route(
            '/api/tasks/{task_id}', plugin_endpoint(delete_task, permission='task_demo:write'), methods=['DELETE']
        )
        return app

    return PluginDefinition(app_factory=create_app)


async def health(context: PluginHealthContext) -> dict[str, Any]:
    """
    只读验证任务表及当前版本新增字段，不执行 DDL 或修复。

    :param context: 宿主健康检查上下文
    :return: 明确包含布尔 ok 的健康结果
    """
    statement = select(tasks).limit(1)
    try:
        if context.query_db is not None:
            await context.query_db.execute(statement)
        else:
            if _runtime.session_factory is None:
                return {'ok': False, 'status': 'unavailable', 'message': '宿主未提供数据库检查会话'}
            async with _runtime.session_factory() as db:
                await db.execute(statement)
    except Exception:
        return {'ok': False, 'status': 'unhealthy', 'message': '任务表或 priority 字段不可读，请检查迁移记录'}
    return {'ok': True, 'status': 'healthy', 'message': '任务表及 priority 字段可读'}