/**
 * 流转树双模式可视化 — 焦点模式 + 全景模式
 */
import { memo, useMemo, useState } from "react";
import { GitBranch, AlertTriangle, Clock, CheckCircle, Flag, FileText, X } from "lucide-react";
import type { TaskResponse } from "../../types/api";
import { TASK_STATUS } from "../../types/api";
import { getStatusConfig } from "../../constants/task";
import type { ModalTarget } from "./TaskTreeViewer";

// ============================================================
// 工具
// ============================================================
function fmtTime(d: string | null) { if (!d) return ""; const dt = new Date(d); const pad = (n: number) => String(n).padStart(2, "0"); return `${dt.getFullYear()}-${pad(dt.getMonth() + 1)}-${pad(dt.getDate())} ${pad(dt.getHours())}:${pad(dt.getMinutes())}`; }
function isMain(t: TaskResponse) { return !t.parent_task_id || t.task_type === "TRANSFER" || t.task_type === "RECOVERY"; }
/** 寻根算法：从任意任务向上攀爬，找到最近的视觉主干节点 ID */
function getRootMainId(t: TaskResponse, flatMap: Record<string, TaskResponse>): string {
  let curr: TaskResponse = t;
  while (curr.parent_task_id && flatMap[curr.parent_task_id]) {
    const p = flatMap[curr.parent_task_id];
    if (isMain(p)) return p.id;
    curr = p;
  }
  return curr.parent_task_id || curr.id;
}
function active(s: string) { return s === "WIP" || s === "PENDING"; }
/** 微型右箭头 SVG */
function ArrowRight({ color = "#9ca3af" }: { color?: string }) {
  return <svg className="h-3 w-3 shrink-0" viewBox="0 0 8 8"><polygon points="0,0 8,4 0,8" fill={color} /></svg>;
}
/** 微型左箭头 SVG */
function ArrowLeft({ color = "#9ca3af" }: { color?: string }) {
  return <svg className="h-3 w-3 shrink-0" viewBox="0 0 8 8"><polygon points="8,0 0,4 8,8" fill={color} /></svg>;
}
function parseImages(s: string | null | undefined): string[] { if (!s) return []; try { return JSON.parse(s); } catch { return []; } }
function imageUrl(u: string) { if (!u) return ""; return u.startsWith("http") ? u : import.meta.env.VITE_API_BASE_URL + (u.startsWith("/") ? u : "/" + u); }

const ALL_TASKS = new Set<TaskResponse>();
function collectAll(tasks: TaskResponse[]) { tasks.forEach(t => { ALL_TASKS.add(t); if (t.child_tasks) collectAll(t.child_tasks); }); }
function findParent(child: TaskResponse): TaskResponse | undefined { for (const t of ALL_TASKS) { if (t.id === child.parent_task_id) return t; } return undefined; }

// ============================================================
// 极简卡片
// ============================================================
const SlimCard = memo(function SlimCard({
  task, assigneeName, active, legacy, onAction, currentUser, onViewRecords, rootMainId,
}: {
  task: TaskResponse; assigneeName?: string; active: boolean; legacy?: boolean;
  onAction: (t: ModalTarget) => void; currentUser?: { username?: string; role?: string } | null;
  onViewRecords?: (t: TaskResponse) => void;
  rootMainId?: string;
}) {
  const cfg = getStatusConfig(task.status);
  const isOwner = !!(currentUser?.username && task.assignee_id === currentUser.username);
  const isManager = currentUser?.role === "SUPER_ADMIN" || currentUser?.role === "SUPERVISOR";
  const main = isMain(task);
  const isNestedSpawn = !main && rootMainId && task.parent_task_id !== rootMainId && !!task.parent_task_id;

  return (
    <div className={`relative w-44 shrink-0 rounded-lg border bg-white p-2.5 shadow-sm ${active ? "border-blue-400 ring-1 ring-blue-100" : "border-gray-200 opacity-75"} ${legacy ? "border-orange-300 animate-pulse" : ""} ${task.is_rework ? "border-l-red-500 border-l-2" : ""}`}>
      <div className={`absolute -top-1.5 right-2 rounded px-1.5 py-px text-[8px] font-bold text-white ${main ? "bg-blue-500" : "bg-purple-500"}`}>{main ? "主线" : "分支"}</div>
      <p className="mt-1 text-xs font-bold text-gray-800 truncate">{task.task_name}</p>
      <div className="mt-1 flex items-center gap-1">
        <span className={`rounded-full px-1.5 py-px text-[8px] font-medium ${cfg.bg} ${cfg.text}`}>{cfg.label}</span>
        <span className="text-[9px] text-gray-400 truncate">{assigneeName || task.assignee_id || "—"}</span>
      </div>
      {/* 单行时间 */}
      <p className="mt-1 text-[8px] text-gray-300">
        ⏰ {fmtTime(task.created_at).split(" ")[0]}
        {task.completed_at ? ` → ${fmtTime(task.completed_at).split(" ")[0]}` : " → 至今"}
      </p>
      {legacy && <p className="mt-1 text-[8px] text-orange-500">源自: {assigneeName || (findParent(task)?.assignee_id) || "历史任务"}</p>}
      {isNestedSpawn && <p className="mt-1 text-[8px] text-purple-500">协助: {findParent(task)?.assignee_id || "—"}</p>}
      {/* 操作按钮 */}
      {active && isOwner && (
        <div className="mt-1.5 flex gap-1 border-t border-gray-100 pt-1.5">
          {task.status?.toUpperCase() === TASK_STATUS.PENDING && <button onClick={() => onAction({ task, action: "receive" })} className="flex-1 rounded border border-blue-200 bg-blue-50 py-0.5 text-[8px] text-blue-600">接收</button>}
          {task.status?.toUpperCase() !== TASK_STATUS.PENDING && <button onClick={() => onAction({ task, action: "transfer" })} className="flex-1 rounded border border-green-200 bg-green-50 py-0.5 text-[8px] text-green-600">转交</button>}
          <button onClick={() => onAction({ task, action: "reject" })} className="flex-1 rounded border border-red-200 bg-red-50 py-0.5 text-[8px] text-red-500">驳回</button>
        </div>
      )}
      {active && !isOwner && isManager && (
        <div className="mt-1.5 flex gap-1 border-t border-orange-100 pt-1.5">
          <button onClick={() => onAction({ task, action: "reject" })} className="flex-1 rounded border border-orange-200 bg-orange-50 py-0.5 text-[8px] text-orange-600">强制驳回</button>
          <button onClick={() => onAction({ task, action: "transfer" })} className="flex-1 rounded border border-orange-200 bg-orange-50 py-0.5 text-[8px] text-orange-600">强制转交</button>
        </div>
      )}
      {/* 记录 */}
      {task.records && task.records.length > 0 && (
        <div onClick={(e) => { e.stopPropagation(); onViewRecords?.(task); }} className="mt-1 cursor-pointer rounded bg-blue-50 px-1.5 py-0.5 text-[8px] text-blue-600 hover:bg-blue-100">
          <FileText className="mr-0.5 inline h-2.5 w-2.5" />{task.records.length}条
        </div>
      )}
    </div>
  );
});

// ============================================================
// 主视图
// ============================================================
interface TaskFlowViewProps {
  tasks: TaskResponse[]; onAction: (t: ModalTarget) => void;
  currentUser?: { username?: string; role?: string } | null;
  assigneeNames?: Record<string, string>;
}

export const TaskFlowView = memo(function TaskFlowView({ tasks, onAction, currentUser, assigneeNames }: TaskFlowViewProps) {
  const [showFullMap, setShowFullMap] = useState(false);
  const [recordsTask, setRecordsTask] = useState<TaskResponse | null>(null);

  // 数据分类 — 🚀 虚拟扁平化：三层+嵌套协助统一挂在视觉主干下
  const { activeMain, historicalMain, subsByRootMain, rootMainMap } = useMemo(() => {
    ALL_TASKS.clear(); if (tasks.length) collectAll(tasks);
    const all = Array.from(ALL_TASKS);
    // 拍平映射
    const flatMap: Record<string, TaskResponse> = {};
    for (const t of all) flatMap[t.id] = t;
    // 计算每个 sub 任务的视觉根主干 ID
    const rootMap: Record<string, string> = {};
    const srm: Record<string, TaskResponse[]> = {};
    const am: TaskResponse[] = []; const hm: TaskResponse[] = [];
    for (const t of all) {
      if (isMain(t)) {
        if (active(t.status)) am.push(t); else hm.push(t);
        srm[t.id] = [];
      }
    }
    // 非主线任务：按根主干分组
    for (const t of all) {
      if (isMain(t)) continue;
      const rootId = getRootMainId(t, flatMap);
      rootMap[t.id] = rootId;
      if (!srm[rootId]) srm[rootId] = [];
      srm[rootId].push(t);
    }
    // 排序
    am.sort((a, b) => new Date(a.created_at).getTime() - new Date(b.created_at).getTime());
    hm.sort((a, b) => new Date(a.created_at).getTime() - new Date(b.created_at).getTime());
    // 🚀 层级排序：直接子节点优先，嵌套子节点跟在父节点之后
    for (const key of Object.keys(srm)) {
      const subs = srm[key];
      // 构建父子索引
      const childMap: Record<string, TaskResponse[]> = {};
      for (const s of subs) {
        const pid = s.parent_task_id || '';
        if (!childMap[pid]) childMap[pid] = [];
        childMap[pid].push(s);
      }
      Object.values(childMap).forEach(arr => arr.sort((a, b) => new Date(a.created_at).getTime() - new Date(b.created_at).getTime()));
      // 递归收集：父 → 子 → 孙
      const ordered: TaskResponse[] = [];
      const collect = (parentId: string) => {
        const kids = childMap[parentId] || [];
        for (const k of kids) {
          ordered.push(k);
          collect(k.id);
        }
      };
      collect(key); // 从根主干开始收集
      srm[key] = ordered;
    }
    return { activeMain: am, historicalMain: hm, subsByRootMain: srm, rootMainMap: rootMap };
  }, [tasks]);

  const allMains = [...historicalMain, ...activeMain];

  return (
    <div>
      {/* 模式切换 */}
      <div className="mb-3 flex justify-center">
        <button onClick={() => setShowFullMap(!showFullMap)}
          className="rounded-full bg-gray-100 px-4 py-1.5 text-xs font-medium text-gray-600 hover:bg-gray-200 transition-colors">
          {showFullMap ? "🔼 收起，仅看当前并发任务" : "👁️ 展开全景流转树 (查看包含已完工在内的完整历史)"}
        </button>
      </div>

      {/* ─── 焦点模式 ─── */}
      {!showFullMap && (
        <div className="flex flex-col items-center gap-4">
          {activeMain.map(mainTask => {
            const children = subsByRootMain[mainTask.id] || [];
            const leftSubs = children.filter((_, i) => i % 2 === 0);
            const rightSubs = children.filter((_, i) => i % 2 === 1);
            return (
              <div key={mainTask.id} className="flex flex-row items-start w-full">
                {/* 左翼 */}
                <div className="flex-1 flex flex-col items-end justify-center gap-2 pr-2">
                  {leftSubs.map(t => {
                    const isLegacy = !active(mainTask.status);
                    return (
                      <div key={t.id} className="flex items-center">
                        <SlimCard task={t} active legacy={isLegacy} assigneeName={assigneeNames?.[t.assignee_id || ""]} onAction={onAction} currentUser={currentUser} onViewRecords={setRecordsTask} rootMainId={mainTask.id} />
                        <div className="flex items-center">
                          <ArrowLeft color={isLegacy ? "#fdba74" : "#9ca3af"} />
                          <div className={`w-5 border-t-2 ${isLegacy ? "border-dashed border-orange-300" : "border-solid border-gray-400"}`} />
                        </div>
                      </div>
                    );
                  })}
                </div>
                {/* 中央主干 */}
                <div className="shrink-0 z-10">
                  <SlimCard task={mainTask} active assigneeName={assigneeNames?.[mainTask.assignee_id || ""]} onAction={onAction} currentUser={currentUser} onViewRecords={setRecordsTask} />
                </div>
                {/* 右翼 */}
                <div className="flex-1 flex flex-col items-start justify-center gap-2 pl-2">
                  {rightSubs.map(t => {
                    const isLegacy = !active(mainTask.status);
                    return (
                      <div key={t.id} className="flex items-center">
                        <div className="flex items-center">
                          <div className={`w-5 border-t-2 ${isLegacy ? "border-dashed border-orange-300" : "border-solid border-gray-400"}`} />
                          <ArrowRight color={isLegacy ? "#fdba74" : "#9ca3af"} />
                        </div>
                        <SlimCard task={t} active legacy={isLegacy} assigneeName={assigneeNames?.[t.assignee_id || ""]} onAction={onAction} currentUser={currentUser} onViewRecords={setRecordsTask} rootMainId={mainTask.id} />
                      </div>
                    );
                  })}
                </div>
              </div>
            );
          })}
          {activeMain.length === 0 && <p className="text-xs text-gray-400 py-4">当前无活跃主线任务</p>}
        </div>
      )}

      {/* ─── 全景模式 ─── */}
      {showFullMap && (
        <div className="space-y-6">
          {allMains.map(mainTask => {
            const children = subsByRootMain[mainTask.id] || [];
            const hasLegacyActive = children.some(c => !isMain(c) && !active(mainTask.status));
            const leftChildren = children.filter((_, i) => i % 2 === 0);
            const rightChildren = children.filter((_, i) => i % 2 === 1);
            const lineStyle = hasLegacyActive && !active(mainTask.status);

            return (
              <div key={mainTask.id} className="relative">
                <div className="absolute left-1/2 top-0 bottom-0 w-0.5 bg-gray-200 -translate-x-1/2 z-0" />
                <div className="flex flex-row items-start w-full">
                  {/* 左翼 */}
                  <div className="flex-1 flex flex-col items-end justify-center gap-2 pr-2">
                    {leftChildren.map(c => (
                      <div key={c.id} className="flex items-center">
                        <SlimCard task={c} active={active(c.status)} legacy={lineStyle}
                          assigneeName={assigneeNames?.[c.assignee_id || ""]} onAction={onAction} currentUser={currentUser} onViewRecords={setRecordsTask} rootMainId={mainTask.id} />
                        <div className="flex items-center">
                          <ArrowLeft color={lineStyle ? "#fdba74" : "#9ca3af"} />
                          <div className={`w-5 border-t-2 ${lineStyle ? "border-dashed border-orange-300" : "border-solid border-gray-400"}`} />
                        </div>
                      </div>
                    ))}
                  </div>
                  {/* 中央 */}
                  <div className="shrink-0 z-10 relative">
                    <SlimCard task={mainTask} active={active(mainTask.status)}
                      assigneeName={assigneeNames?.[mainTask.assignee_id || ""]} onAction={onAction} currentUser={currentUser} onViewRecords={setRecordsTask} />
                    {active(mainTask.status) && (
                      <div className="absolute -top-1 -left-1 h-3 w-3 rounded-full bg-green-400 border-2 border-white" />
                    )}
                  </div>
                  {/* 右翼 */}
                  <div className="flex-1 flex flex-col items-start justify-center gap-2 pl-2">
                    {rightChildren.map(c => (
                      <div key={c.id} className="flex items-center">
                        <div className="flex items-center">
                          <div className={`w-5 border-t-2 ${lineStyle ? "border-dashed border-orange-300" : "border-solid border-gray-400"}`} />
                          <ArrowRight color={lineStyle ? "#fdba74" : "#9ca3af"} />
                        </div>
                        <SlimCard task={c} active={active(c.status)} legacy={lineStyle}
                          assigneeName={assigneeNames?.[c.assignee_id || ""]} onAction={onAction} currentUser={currentUser} onViewRecords={setRecordsTask} rootMainId={mainTask.id} />
                      </div>
                    ))}
                  </div>
                </div>

                {allMains.indexOf(mainTask) < allMains.length - 1 && (
                  <div className="flex justify-center py-2">
                    <span className="text-[10px] text-gray-300">▼</span>
                  </div>
                )}
              </div>
            );
          })}
          {allMains.length === 0 && <p className="text-center text-xs text-gray-400 py-8">暂无流转记录</p>}
        </div>
      )}

      {/* 记录弹窗 */}
      {recordsTask && (
        <div className="fixed inset-0 z-50 flex items-center justify-center">
          <div className="absolute inset-0 bg-black/40 backdrop-blur-sm" onClick={() => setRecordsTask(null)} />
          <div className="relative z-10 mx-4 max-h-[80vh] w-full max-w-md overflow-y-auto rounded-xl bg-white p-5 shadow-2xl">
            <div className="mb-3 flex items-center justify-between"><h3 className="text-sm font-bold">提交记录 — {recordsTask.task_name}</h3><button onClick={() => setRecordsTask(null)} className="rounded p-1 text-gray-400 hover:bg-gray-100"><X className="h-4 w-4" /></button></div>
            {(recordsTask.records || []).length === 0 ? <p className="py-8 text-center text-sm text-gray-400">暂无记录</p> :
              <div className="space-y-2">{[...recordsTask.records!].reverse().map((r, i) => (
                <div key={r.id} className="flex gap-2">
                  <div className={`mt-1.5 h-2 w-2 shrink-0 rounded-full ${i === 0 ? "bg-blue-500" : "bg-gray-300"}`} />
                  <div className="flex-1 rounded bg-gray-50 px-3 py-2"><p className="text-[10px] text-gray-400">{fmtTime(r.created_at)}</p>
                    {(r.note || r.remark) && <p className="mt-0.5 text-xs text-gray-700">{r.note || r.remark}</p>}
                    {(() => { const imgs = parseImages((r as any).images); if (!imgs.length) return null; return <div className="mt-1 flex gap-1">{imgs.map((img, j) => <img key={j} src={imageUrl(img)} className="h-12 w-12 rounded border object-cover cursor-pointer" onClick={() => window.open(imageUrl(img))} />)}</div>; })()}
                  </div>
                </div>
              ))}</div>}
          </div>
        </div>
      )}
    </div>
  );
});

export default TaskFlowView;