/**
 * AGC Unity 插件的 agc.plugin.v1 入口。
 * 与内置 Cocos 插件相同，直接运行的 JS 使用 SDK 的宿主协议；全部编辑器副作用
 * 经 host.rpc 交给统一原生服务，入口不查找进程、不启动 helper、不持有凭据。
 */
import { pathToFileURL } from 'node:url';

export const UNITY_PLUGIN_PROTOCOL_VERSION = 'agc.plugin.v1';
export const UNITY_EXECUTE_COMMAND_ID = 'unity.editor.execute';
export const UNITY_CONNECTION_CAPABILITY_ID = 'unity.editor.connection';
const MAX_MESSAGE_BYTES = 2 * 1024 * 1024;
const MAX_CODE_BYTES = 128 * 1024;

export function createUnityEditorPlugin({ send, timeoutMs = 85_000 }) {
  let nextId = 1;
  let activeProjectPath = null;
  let projectEpoch = 0;
  let disposed = false;
  let executing = false;
  let uncertain = false;
  const pending = new Map();

  function request(method, params) {
    if (disposed) return Promise.reject(new Error('插件已停止'));
    const id = nextId++;
    return new Promise((resolve, reject) => {
      const timer = setTimeout(() => {
        pending.delete(id);
        reject(new Error('Unity 插件宿主 RPC 超时'));
      }, timeoutMs);
      pending.set(id, { resolve, reject, timer });
      try {
        send({ jsonrpc: '2.0', id, method, params });
      } catch (error) {
        clearTimeout(timer);
        pending.delete(id);
        reject(error);
      }
    });
  }

  function editorParams(input, allowed) {
    if (!input || typeof input !== 'object' || Array.isArray(input)) {
      throw new Error('Unity 参数必须是对象');
    }
    for (const key of Object.keys(input)) {
      if (!allowed.includes(key)) throw new Error(`Unity 不接受参数：${key}`);
    }
    if (!activeProjectPath) throw new Error('当前没有受控 Unity 项目');
    if (
      input.timeoutMs !== undefined &&
      (!Number.isInteger(input.timeoutMs) ||
        input.timeoutMs < 1 ||
        input.timeoutMs > 60_000)
    ) {
      throw new Error('timeoutMs 必须在 1..60000 之间');
    }
    return { ...input, projectPath: activeProjectPath };
  }

  function reconcile(error) {
    uncertain = true;
    return {
      ok: false,
      status: 'needs-reconciliation',
      retryAllowed: false,
      dispatched: true,
      error: {
        code: 'execution-uncertain',
        message: typeof error === 'string' ? error : 'Unity 执行结果待核对',
      },
    };
  }

  async function execute(input) {
    const params = editorParams(input, ['code', 'timeoutMs']);
    if (
      typeof params.code !== 'string' ||
      !params.code.trim() ||
      params.code.includes('\0') ||
      Buffer.byteLength(params.code) > MAX_CODE_BYTES
    ) {
      throw new Error('Unity C# 代码必须非空、不含 NUL 且不超过 128 KiB');
    }
    if (uncertain)
      return reconcile('先前执行结果待核对，请核对 Unity 后重启客户端');
    if (executing) {
      return {
        ok: false,
        status: 'failed',
        dispatched: false,
        retryAllowed: false,
        error: { code: 'editor-busy', message: 'Unity 已有执行正在处理' },
      };
    }
    executing = true;
    try {
      const result = await request('host.rpc', {
        method: 'editor.execute',
        params,
      });
      if (result?.status === 'needs-reconciliation')
        return reconcile(result.error?.message);
      const validError =
        typeof result?.error?.code === 'string' &&
        result.error.code.trim() &&
        typeof result?.error?.message === 'string' &&
        result.error.message.trim();
      if (
        !result ||
        typeof result.ok !== 'boolean' ||
        typeof result.dispatched !== 'boolean' ||
        result.retryAllowed !== false ||
        !(
          (result.status === 'completed' &&
            result.ok &&
            result.dispatched &&
            !Object.hasOwn(result, 'error') &&
            Object.hasOwn(result, 'result')) ||
          (result.status === 'failed' &&
            !result.ok &&
            validError &&
            !Object.hasOwn(result, 'result'))
        )
      ) {
        return reconcile('Unity 执行回执无效');
      }
      return result;
    } catch {
      return reconcile('Unity 执行连接中断或超时，结果待核对');
    } finally {
      executing = false;
    }
  }

  async function connection(input = {}) {
    const params = editorParams(input, ['operation', 'processId', 'timeoutMs']);
    const operation = params.operation ?? 'detect';
    if (!['detect', 'connect', 'status', 'disconnect'].includes(operation)) {
      throw new Error('不支持的 Unity 连接操作');
    }
    if (
      params.processId !== undefined &&
      (!Number.isInteger(params.processId) || params.processId <= 0)
    ) {
      throw new Error('processId 必须是正整数');
    }
    delete params.operation;
    return request('host.rpc', { method: `editor.${operation}`, params });
  }

  async function handleMessage(message) {
    if (disposed) return;
    const value = typeof message === 'string' ? JSON.parse(message) : message;
    if (!value || value.jsonrpc !== '2.0') return;
    if (value.method === 'host.event') {
      if (value.params?.type === 'project.changed') {
        const project = value.params.payload?.projectPath;
        activeProjectPath =
          typeof project === 'string' && project ? project : null;
        projectEpoch += 1;
      }
      return;
    }
    if (value.method !== undefined) {
      if (value.id === undefined) return;
      try {
        const handler =
          value.method === UNITY_EXECUTE_COMMAND_ID
            ? execute
            : value.method === UNITY_CONNECTION_CAPABILITY_ID
              ? connection
              : null;
        if (!handler) throw new Error('插件未注册该方法');
        const result = await handler(value.params ?? {});
        if (!disposed) send({ jsonrpc: '2.0', id: value.id, result });
      } catch (error) {
        if (!disposed) {
          if (value.method === UNITY_EXECUTE_COMMAND_ID) {
            send({
              jsonrpc: '2.0',
              id: value.id,
              result: {
                ok: false,
                status: 'failed',
                retryAllowed: false,
                dispatched: false,
                error: { code: 'invalid-input', message: error.message },
              },
            });
          } else {
            send({
              jsonrpc: '2.0',
              id: value.id,
              error: { code: -32602, message: error.message },
            });
          }
        }
      }
      return;
    }
    const item = pending.get(value.id);
    if (!item) return;
    pending.delete(value.id);
    clearTimeout(item.timer);
    if (value.error) item.reject(new Error('插件宿主拒绝请求'));
    else item.resolve(value.result);
  }

  async function start() {
    await request('host.registerCommand', {
      id: UNITY_EXECUTE_COMMAND_ID,
      title: '执行 Unity C#',
      description: '在当前 Unity 项目的编辑器主线程执行 C#',
    });
    await request('host.registerCapability', {
      id: UNITY_CONNECTION_CAPABILITY_ID,
      description: '当前 Unity 项目的编辑器连接与状态',
    });
    const epoch = projectEpoch;
    const result = await request('host.events.subscribe', {
      type: 'project.changed',
    });
    if (epoch === projectEpoch) activeProjectPath = result?.projectPath ?? null;
  }

  function dispose() {
    disposed = true;
    for (const item of pending.values()) {
      clearTimeout(item.timer);
      item.reject(new Error('插件已停止'));
    }
    pending.clear();
  }
  return { start, handleMessage, dispose };
}

export function startUnityEditorStdioPlugin({
  stdin = process.stdin,
  stdout = process.stdout,
} = {}) {
  const plugin = createUnityEditorPlugin({
    send(message) {
      const line = `${JSON.stringify(message)}\n`;
      if (Buffer.byteLength(line) > MAX_MESSAGE_BYTES)
        throw new Error('插件消息过大');
      stdout.write(line);
    },
  });
  let buffer = '';
  let stopped = false;
  const stop = () => {
    stopped = true;
    buffer = '';
    plugin.dispose();
    stdin.pause();
  };
  stdin.setEncoding('utf8');
  stdin.on('data', (chunk) => {
    if (stopped) return;
    buffer += chunk;
    let boundary;
    while ((boundary = buffer.indexOf('\n')) >= 0) {
      const line = buffer.slice(0, boundary);
      buffer = buffer.slice(boundary + 1);
      if (Buffer.byteLength(line) > MAX_MESSAGE_BYTES) {
        stop();
        return;
      }
      if (line.trim()) void plugin.handleMessage(line).catch(stop);
    }
    if (Buffer.byteLength(buffer) > MAX_MESSAGE_BYTES) stop();
  });
  stdin.on('end', stop);
  stdin.on('error', stop);
  void plugin.start().catch(stop);
  return plugin;
}

if (
  process.argv[1] &&
  import.meta.url === pathToFileURL(process.argv[1]).href
) {
  startUnityEditorStdioPlugin();
}