/**
 * 任务流转卡片堆叠视图 — 水平分支 + 卡片层叠布局
 *
 * 与移动端 TaskSwipeCards.vue 核心逻辑完全对齐：
 * - 任务树按 TRANSFER/SPAWN 分类为主线/分支
 * - 状态标签、时间格式、卡片元素一致
 * - 三种权限模式（本人/管理员/只读）
 */
import { memo, useMemo } from "react";
import {
  GitBranch,
  ArrowDown,
  AlertTriangle,
  Clock,
  CheckCircle,
  Flag,
  FileText,
} 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";

// ============================================================
// 工具函数 — 与移动端 fmtTime/statusLabel 完全一致
// ============================================================

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())}`;
}

/** 判断任务是否为主线（与移动端 isMain 逻辑一致） */
function isMainTask(t: TaskResponse): boolean {
  return !t.parent_task_id || t.task_type === "TRANSFER" || t.task_type === "RECOVERY"
      || (!t.task_type && !!t.parent_task_id);
}

// ============================================================
// 类型
// ============================================================

interface LevelGroup {
  depth: number;
  tasks: TaskResponse[];
}

// ============================================================
// 任务树解析 — 按 depth 拍平（与移动端 lanes 逻辑结构等价）
// ============================================================

function flattenLevels(tasks: TaskResponse[], depth: number = 0): LevelGroup[] {
  const result: LevelGroup[] = [];
  if (!tasks || tasks.length === 0) return result;
  result.push({ depth, tasks });
  for (const t of tasks) {
    if (t.child_tasks && t.child_tasks.length > 0) {
      result.push(...flattenLevels(t.child_tasks, depth + 1));
    }
  }
  return result;
}

function groupByDepth(levels: LevelGroup[]): Map<number, TaskResponse[]> {
  const map = new Map<number, TaskResponse[]>();
  for (const lvl of levels) {
    if (!map.has(lvl.depth)) map.set(lvl.depth, []);
    const existing = map.get(lvl.depth)!;
    for (const t of lvl.tasks) {
      if (!existing.find((e) => e.id === t.id)) existing.push(t);
    }
  }
  return map;
}

// ============================================================
// 单张任务卡片 — 与移动端 ss-card 完全对齐
// ============================================================

const FlowCard = memo(function FlowCard({
  task,
  isActive,
  onAction,
  currentUser,
  assigneeName,
}: {
  task: TaskResponse;
  isActive: boolean;
  onAction: (target: ModalTarget) => void;
  currentUser?: { username?: string; role?: string } | null;
  assigneeName?: string;
}) {
  const cfg = getStatusConfig(task.status);
  const dwell = calcDwell(task.received_at, task.completed_at, task.status);
  const isCompleted = task.status?.toUpperCase() === TASK_STATUS.COMPLETED;
  const isArchived = task.status?.toUpperCase() === TASK_STATUS.ARCHIVED;
  const isCanceled = task.status?.toUpperCase() === "CANCELED";
  const main = isMainTask(task);

  // 权限：本人或管理员
  const isOwner = !!(currentUser?.username && task.assignee_id === currentUser.username);
  const isManager = currentUser?.role === "SUPER_ADMIN" || currentUser?.role === "SUPERVISOR";
  const canOperate = isOwner || isManager;

  return (
    <div
      className={`relative shrink-0 w-56 rounded-xl border-2 bg-white p-3.5 shadow-md transition-all ${
        isActive
          ? `border-blue-400 ${cfg.ring} shadow-lg shadow-blue-100 scale-105 z-10`
          : isCompleted || isArchived
            ? "border-gray-200 opacity-70"
            : isCanceled
              ? "border-gray-200 opacity-50"
              : "border-gray-200 hover:shadow-lg"
      } ${task.is_rework ? "border-l-red-500 border-l-4" : ""}`}
    >
      {/* 主线/分支 角标 — 与移动端 tc-ribbon 一致 */}
      <div
        className={`absolute top-3 right-3 rounded px-2 py-0.5 text-[9px] font-bold text-white z-2 ${
          main ? "bg-blue-600" : "bg-purple-500"
        }`}
      >
        {main ? "主分支" : "分支"}
      </div>

      {/* 返工/入库标记 — 与移动端 tag-rework-sm 一致 */}
      <div className="mb-1 flex flex-wrap gap-1">
        {task.is_rework && (
          <span className="inline-flex items-center rounded bg-red-600 px-1.5 py-0.5 text-[9px] font-bold text-white animate-pulse">
            <AlertTriangle className="mr-0.5 h-2.5 w-2.5" />返工
          </span>
        )}
        {task.status === "ARCHIVED" && (
          <span className="inline-flex items-center rounded border border-dashed border-purple-300 bg-purple-50 px-1.5 py-0.5 text-[9px] font-bold text-purple-600">
            📦 入库
          </span>
        )}
      </div>

      {/* 头部：类型标签 + 状态 — 与移动端 tc-head 一致 */}
      <div className="flex items-center justify-between mt-1">
        <div className="flex items-center gap-1.5 flex-wrap">
          <span className={`rounded px-2 py-0.5 text-[9px] font-bold text-white ${main ? "bg-blue-600" : "bg-purple-100 text-purple-700"}`}>
            {main ? "主分支" : "分支"}
          </span>
          {task.child_tasks.length > 1 && (
            <span className="inline-flex items-center rounded bg-purple-100 px-1.5 py-0.5 text-[9px] font-medium text-purple-700">
              <GitBranch className="mr-0.5 h-2.5 w-2.5" />
              裂变×{task.child_tasks.length}
            </span>
          )}
        </div>
        <span className={`inline-flex items-center rounded-full px-2 py-0.5 text-[10px] font-medium ${cfg.bg} ${cfg.text}`}>
          {cfg.label}
        </span>
      </div>

      {/* 任务名 — 与移动端 tc-name 一致 */}
      <p className="mt-2 text-base font-extrabold text-gray-800 leading-tight">{task.task_name}</p>

      {/* 负责人 — 与移动端 tc-meta 一致 */}
      <div className="mt-2 flex items-center gap-2 text-[11px]">
        <span className="text-gray-400">👤 负责人</span>
        <span className="font-semibold text-gray-700">{assigneeName || task.assignee_id || "未分配"}</span>
      </div>

      {/* 备注 — 与移动端 tc-remark-box 一致 */}
      {task.remark && (
        <div className="mt-2 rounded-lg border border-yellow-200 bg-yellow-50 px-2.5 py-2">
          <p className="text-[10px] font-bold text-yellow-700">📌 备注</p>
          <p className="mt-0.5 text-[11px] text-gray-700 leading-relaxed">{task.remark}</p>
        </div>
      )}

      {/* 提交记录 — 与移动端 tc-records-link 一致 */}
      {task.records && task.records.length > 0 && (
        <div className="mt-2 flex items-center gap-1.5 rounded-lg border border-blue-200 bg-gradient-to-r from-blue-50 to-indigo-50 px-2.5 py-2">
          <FileText className="h-3.5 w-3.5 text-blue-500" />
          <span className="flex-1 text-[11px] font-bold text-blue-600">
            共 {task.records.length} 条提交记录
          </span>
        </div>
      )}

      {/* 停留耗时 — 与移动端逻辑一致 */}
      {dwell && (
        <p className={`mt-1.5 flex items-center gap-1 text-[10px] ${dwell.highlight ? "text-red-500 font-semibold" : "text-orange-500"}`}>
          <Clock className="h-3 w-3" />
          {dwell.highlight ? <span className="animate-pulse">⏳ 停留: {dwell.text}</span> : <span>耗时: {dwell.text}</span>}
        </p>
      )}

      {/* 驳回原因 */}
      {task.reject_reason && (
        <p className="mt-1 text-[10px] text-red-500 line-clamp-2">驳回原因: {task.reject_reason}</p>
      )}

      {/* 状态标记 — 与移动端 tc-stats 一致 */}
      <div className="mt-2 flex flex-wrap gap-1.5">
        {task.received_at && (
          <span className="inline-flex items-center gap-1 rounded-md bg-gray-100 px-1.5 py-0.5 text-[9px] font-semibold text-gray-600">
            <CheckCircle className="h-2.5 w-2.5" />已接收
          </span>
        )}
        {task.completed_at && (
          <span className="inline-flex items-center gap-1 rounded-md bg-green-50 px-1.5 py-0.5 text-[9px] font-semibold text-green-600">
            <Flag className="h-2.5 w-2.5" />已完工
          </span>
        )}
      </div>

      {/* 时间 — 与移动端 fmtTime 格式一致 */}
      <div className="mt-2 border-t border-gray-100 pt-2">
        <p className="text-[9px] text-gray-400">创建: {fmtTime(task.created_at)}</p>
        {task.received_at && <p className="text-[9px] text-gray-400">接收: {fmtTime(task.received_at)}</p>}
        {task.completed_at && <p className="text-[9px] text-gray-400">完工: {fmtTime(task.completed_at)}</p>}
      </div>

      {/* 操作按钮 — 三种权限模式 */}
      {isActive && canOperate && (
        <div className="mt-2 flex gap-1.5 border-t border-gray-100 pt-2">
          {task.status?.toUpperCase() === TASK_STATUS.PENDING && (
            <>
              <button onClick={() => onAction({ task, action: "receive" })}
                className="flex-1 rounded border border-blue-200 bg-blue-50 py-1 text-[10px] font-medium text-blue-600 hover:bg-blue-100">
                接收
              </button>
              <button onClick={() => onAction({ task, action: "reject" })}
                className="rounded border border-red-200 bg-red-50 px-2 py-1 text-[10px] font-medium text-red-500 hover:bg-red-100">
                驳回
              </button>
              <button onClick={() => onAction({ task, action: "transfer" })}
                className="rounded border border-green-200 bg-green-50 px-2 py-1 text-[10px] font-medium text-green-600 hover:bg-green-100">
                转交
              </button>
            </>
          )}
          {task.status?.toUpperCase() === TASK_STATUS.WIP && (
            <>
              <button onClick={() => onAction({ task, action: "reject" })}
                className="flex-1 rounded border border-red-200 bg-red-50 py-1 text-[10px] font-medium text-red-500 hover:bg-red-100">
                驳回
              </button>
              <button onClick={() => onAction({ task, action: "transfer" })}
                className="flex-1 rounded border border-green-200 bg-green-50 py-1 text-[10px] font-medium text-green-600 hover:bg-green-100">
                转交
              </button>
            </>
          )}
        </div>
      )}
      {isActive && !isOwner && isManager && (
        <div className="mt-2 border-t border-orange-100 pt-2">
          <p className="mb-1 text-[9px] text-orange-500">⚠ 运维干预模式</p>
          <div className="flex gap-1.5">
            <button onClick={() => onAction({ task, action: "reject" })}
              className="flex-1 rounded border border-orange-200 bg-orange-50 py-1 text-[10px] font-medium text-orange-600 hover:bg-orange-100">
              强制驳回
            </button>
            <button onClick={() => onAction({ task, action: "transfer" })}
              className="flex-1 rounded border border-orange-200 bg-orange-50 py-1 text-[10px] font-medium text-orange-600 hover:bg-orange-100">
              强制转交
            </button>
          </div>
        </div>
      )}
      {isActive && !canOperate && (
        <div className="mt-2 border-t border-gray-100 pt-2">
          <p className="text-center text-[9px] text-gray-400">非当前任务责任人，无法操作</p>
        </div>
      )}
    </div>
  );
});

// ============================================================
// 停留耗时 — 与移动端逻辑一致
// ============================================================

function calcDwell(
  receivedAt: string | null,
  completedAt: string | null,
  status: string,
): { text: string; highlight: boolean } | null {
  if (!receivedAt) return null;
  const start = new Date(receivedAt).getTime();
  const end = completedAt ? new Date(completedAt).getTime() : Date.now();
  const diffMs = end - start;
  if (diffMs < 0) return null;
  const totalMin = Math.floor(diffMs / 60000);
  if (totalMin < 1) return { text: "< 1分钟", highlight: status === "WIP" };
  if (totalMin < 60) return { text: `${totalMin}分钟`, highlight: status === "WIP" };
  const hours = Math.floor(totalMin / 60);
  const remainMin = totalMin % 60;
  if (hours < 24) return { text: `${hours}小时${remainMin > 0 ? remainMin + "分钟" : ""}`, highlight: status === "WIP" };
  const days = Math.floor(hours / 24);
  const remainHr = hours % 24;
  return { text: `${days}天${remainHr > 0 ? remainHr + "小时" : ""}`, highlight: status === "WIP" };
}

// ============================================================
// 主视图
// ============================================================

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

export const TaskFlowView = memo(function TaskFlowView({ tasks, onAction, currentUser, assigneeNames }: TaskFlowViewProps) {
  const depthMap = useMemo(() => {
    if (!tasks || tasks.length === 0) return new Map<number, TaskResponse[]>();
    return groupByDepth(flattenLevels(tasks));
  }, [tasks]);

  const depths = Array.from(depthMap.keys()).sort((a, b) => a - b);
  if (depths.length === 0) return null;

  return (
    <div className="space-y-4">
      {depths.map((depth) => {
        const levelTasks = depthMap.get(depth) || [];
        return (
          <div key={depth}>
            <div className="mb-2 flex items-center gap-2">
              <span className="text-[10px] font-semibold text-gray-400 uppercase tracking-wider">
                {depth === 0 ? "顶层任务" : `第 ${depth} 层子任务`}
              </span>
              <div className="h-px flex-1 bg-gray-100" />
            </div>
            <div className="flex gap-3 overflow-x-auto pb-2 pl-2" style={{ scrollSnapType: "x mandatory" }}>
              {levelTasks.map((task) => {
                const isActive =
                  task.status?.toUpperCase() === TASK_STATUS.PENDING ||
                  task.status?.toUpperCase() === TASK_STATUS.WIP;
                return (
                  <div key={task.id} style={{ scrollSnapAlign: "start" }}>
                    <FlowCard
                      task={task}
                      isActive={isActive}
                      onAction={onAction}
                      currentUser={currentUser}
                      assigneeName={assigneeNames?.[task.assignee_id || ""]}
                    />
                  </div>
                );
              })}
            </div>
            {depth < depths.length - 1 && (
              <div className="flex justify-center py-1">
                <ArrowDown className="h-4 w-4 text-gray-300" />
              </div>
            )}
          </div>
        );
      })}
    </div>
  );
});

export default TaskFlowView;