/**
 * 新版画布的导入/复制任务显示入口。订阅engine已发布状态，选择文件后启动runtime任务，并展示已加入前缀、等待项与失败原因。
 * 面板不保存独立任务事实；暂停/继续/停止由imports实现，停止后已加入内容仍保留，不能把它当成整批回滚。
 */
"use client";

import { useCallback, useRef, useState, useSyncExternalStore } from "react";
import { FolderInput } from "lucide-react";
import type { ProjectEngine } from "@/lib/canvas-runtime/workspace";
import { IconButton } from "@/components/ui/icon-button";
import { errorText } from "@/lib/api";
import styles from "./canvas.module.css";

/** 将记录级错误码转成可读说明，未识别的码使用通用提示；原始错误仍保存在任务记录中。 */
const reason = (code: string) => ({ import_asset_authorization_failed: "资源访问授权失败，此记录未加入", import_asset_capacity: "本组资源过大，无法一次准备", asset_depot_unavailable: "资源仓库暂不可用", import_resource_authorization_required: "资源需要重新授权，此记录尚未加入", invalid_document_import: "导出文档结构不合法", invalid_json_array: "JSON 记录数组格式错误", incomplete_json_array: "JSON 数组尾部不完整", json_nesting_limit: "JSON 嵌套层数过多", invalid_json: "记录格式错误", invalid_json_value: "记录包含不支持的数据", invalid_utf8: "文件编码不是 UTF-8", record_too_large: "单条记录过大", unresolved_dependency: "引用的记录未加入", invalid_native_import_record: "不是画布记录", import_component_unavailable: "元素类型暂不支持", invalid_geometry: "元素尺寸不合法", invalid_endpoint: "连线端点已不存在", duplicate_import_source_key: "记录标识重复", import_source_read_failed: "暂时无法读取源文件，可重试；已加入内容保留", import_source_verification_failed: "源文件校验失败，可重试；已加入内容保留", invalid_import_read_proof: "源文件读取证据不一致，任务已暂停", import_source_unavailable: "导入源文件不可用", import_source_changed: "源文件内容与保存时不一致，任务已暂停", import_source_integrity_unavailable: "旧任务缺少源内容校验，无法安全继续；已加入内容保留", import_source_integrity_missing: "源校验记录缺失，任务已暂停", import_source_integrity_interpreter_unavailable: "源校验版本暂不支持", import_target_missing: "目标分区已不存在", import_target_changed: "目标分区已改变", import_dependency_changed: "引用对象已删除或恢复为新版本", dependency_capacity: "等待引用过多，请调整文件顺序", copy_external_changed: "原图引用已删除、移动或恢复为新版本", invalid_duplicate_source: "复制源数据不可用", invalid_copy_snapshot: "复制快照不可用", invalid_copy_preparation: "复制准备记录不可用", copy_interpreter_changed: "复制规则已变化，需要重新复制", invalid_import_source: "文件过大或格式不支持" } as Record<string,string>)[code] ?? "这条记录暂时无法加入";

/** 只显示目标canvas最近三个任务，倒序展示；任务数量与汇总仅覆盖这个显示窗口，不代表项目全部导入。 */
export function HeadlessImports({ engine, canvasId, viewId }: { engine: ProjectEngine; canvasId: string; viewId:string }) {
  // React订阅唯一发布根，不在组件里复制任务状态；同一个getSnapshot也作为服务端快照入口。
  const subscribe = useCallback((notify: () => void) => engine.editor.subscribe(notify), [engine]);
  const snapshot = useSyncExternalStore(subscribe, engine.getSnapshot, engine.getSnapshot);
  const input = useRef<HTMLInputElement>(null), [open, setOpen] = useState(false), [error, setError] = useState("");
  // 每次渲染更新engine/canvas身份，用于异步文件探测和控制回调完成后避免更新另一画布的错误显示。
  const scope = useRef({ engine, canvasId }); scope.current = { engine, canvasId };
  const jobs = [...(snapshot.runtime.imports?.values() ?? [])].filter(job => job.source?.targetCanvasId === canvasId).slice(-3).reverse();
  /** 统一承接runtime控制Promise的成功/失败；这里只更新面板错误，不自行重排或重启任务。 */
  const control = (work: Promise<void>) => { void work.then(() => { if (scope.current.engine === engine && scope.current.canvasId === canvasId) setError(""); }).catch(error => { if (scope.current.engine === engine && scope.current.canvasId === canvasId) setError(errorText(error)); }); };
  // canStart决定文件入口可用性；input每次先清value，允许再次选择同一个文件。
  // .json读取前64KiB探测首个非空白字符：对象走文档导入，数组走记录数组；其它后缀走NDJSON。
  // 探测前捕获canvas父关系及入口生命周期，await后重新核对，防止向已被替换/移走的目标启动任务。
  // integrityVersion=1源校验未完成显示校验中；=2允许内容继续编辑，但提示校验完成后同步。
  // 任务按钮按runtime状态显示；失败详情最多列前10项，停止提示明确已加入内容继续同步。
  return <aside data-canvas-ui-view={viewId} className={styles.importPanel} aria-label="画布导入">
    <div className={styles.importActions}><IconButton icon={FolderInput} label="导入画布记录" disabled={!engine.imports.canStart(canvasId).enabled} onClick={() => input.current?.click()} /><span>NDJSON / JSON 记录数组</span></div>
    <input data-canvas-import ref={input} type="file" accept=".ndjson,.jsonl,.json,application/json,application/x-ndjson" hidden onChange={async event => {
      const file = event.target.files?.[0]; event.target.value = ""; if (!file) return;
      try { if(file.name.toLowerCase().endsWith('.json')){const before=engine.getSnapshot().document,target=before.canvases.get(canvasId),parent=JSON.stringify(target?.parent),entry=target?.parent?before.elements.get(target.parent.entryElementId)?.incarnation:undefined;const prefix=(await file.slice(0,65536).text()).trimStart()[0];if(scope.current.engine!==engine||scope.current.canvasId!==canvasId)return;const current=engine.getSnapshot().document,now=current.canvases.get(canvasId);if(!target||!now||JSON.stringify(now.parent)!==parent||(now.parent?current.elements.get(now.parent.entryElementId)?.incarnation:undefined)!==entry)throw Error('import_target_changed');if(prefix==='{')engine.imports.startDocument(file,canvasId);else if(prefix==='[')engine.imports.startJsonArray(file,canvasId);else throw Error('invalid_import_source');}else engine.imports.startNdjson(file,canvasId); setOpen(true); setError(""); } catch (error) { if(scope.current.engine===engine&&scope.current.canvasId===canvasId)setError(errorText(error)); }
    }} />
    {jobs.length > 0 && <details open={open} onToggle={event => setOpen(event.currentTarget.open)}><summary>导入与复制任务 · {jobs.some(job => job.status === "preparing") && "正在准备复制 · "}{jobs.reduce((count, job) => count + job.committedSourceKeys.length, 0)} 项已加入</summary>
      {jobs.map((job, index) => <section className={styles.importJob} key={job.id} aria-label={`导入任务 ${index + 1}`}>
        <strong>{job.source?.name || `导入任务 ${index + 1}`}</strong>
        <p role="status">{["running","preparing"].includes(job.status) && job.source?.integrityVersion === 1 && !job.source.sha256 ? "正在校验源文件" : job.status === "preparing" ? "正在准备复制" : job.status === "running" ? "正在加入" : job.status === "paused" ? "已暂停" : job.status === "cancelled" ? "已停止" : job.status === "partial" ? "部分加入" : "已加入画布"} · {job.committedSourceKeys.length} 项{job.pending.length > 0 && `，${job.pending.length} 项等待`}</p>
        {!(job.status==='cancelled'&&!job.committedSourceKeys.length)&&job.source?.integrityVersion===2&&!job.source.sha256&&!job.source.integrityError&&<small>内容可继续编辑，源文件校验完成后同步。</small>}
        {job.source?.retirement?.purgedAt !== undefined && <small>本地源文件已清理；画布内容和撤销记录保留。</small>}
        {job.error && <p>{reason(job.error)}</p>}
        <div className={styles.importActions}>
          {job.source?.integrityError&&<button onClick={()=>control(engine.retry())}>重试源文件校验</button>}
          {["running","preparing"].includes(job.status) && <button onClick={() => control(engine.imports.pause(job.id))}>暂停导入</button>}
          {job.status === "paused" && <button onClick={() => control(engine.imports.resume(job.id))}>继续导入</button>}
          {["running","preparing","paused"].includes(job.status) && <button onClick={() => control(engine.imports.cancel(job.id))}>停止导入</button>}
        </div>
        {job.status === "cancelled" && <small>已加入的内容保留并继续同步。</small>}
        {job.failures.length > 0 && <details><summary>{job.failures.length} 条未加入记录</summary><ul>{job.failures.slice(0, 10).map((failure, item) => <li key={`${failure.key}:${item}`}>{failure.key.startsWith("byte:") ? `文件位置 ${failure.cursor}` : failure.key}：{reason(failure.code)}</li>)}</ul></details>}
      </section>)}
    </details>}
    {error && <p role="alert">{error}{jobs.length > 0 && <button onClick={() => control(engine.retry())}>重试保存</button>}</p>}
  </aside>;
}