"use client";
import { Circle, CircleDot, Pause } from "lucide-react";
import { useCallback, useEffect, useState } from "react";

import { CARD_SURFACE } from "@/components/ui/card";
import { cn } from "@/lib/utils";
import { Collapsible, CollapsibleChevron, CollapsiblePanel, CollapsibleTrigger } from "@/components/ui/collapsible";
import { FLUSH_ROW_INTERACTIVE } from "@/components/ui/interactive";
import { StatusMark } from "@/components/ui/status-mark";

import type { PlanTodo } from "./events";

interface PlanChecklistProps {
  /** 执行期计划清单 (覆盖式刷新); 空数组时不渲染. */
  todos: PlanTodo[];
  /**
   * 本轮是否仍在流式执行中. ``in_progress`` 仅在 ``active`` 时转圈;
   * turn 结束/报错后转 ``false``, 当前步停转 (显示"停在此步"), 不再空转误导.
   */
  active: boolean;
}

/**
 * 执行期"计划清单"实时勾选 (TodoWrite 式): code-agent 批准计划后边执行边刷新各步
 * 状态, 用户看到"做到哪一步了". 渲染在 composer 上方, 由 planTodos 驱动.
 *
 * 进度叙事三件套: 顶部分段进度条 (一段一步) · 左侧轨道串起各步 · 当前步整行铺中性底,
 * 不看文字也知道走到哪. 设计稿见 docs/prototype/todolist/openpencil.
 *
 * 可折叠: 七八步的清单会把对话区挤成一小截, 点标题栏折成一行 (分段条 + 当前步 + 计数).
 * 偏好全局粘性 (localStorage): 折过一次以后所有会话默认折叠, 展开同理.
 * SSR / 首屏恒为展开, 水合后 effect 读偏好校正 (与 ComposerSizeProvider 同款).
 */
export const PlanChecklist = ({ todos, active }: PlanChecklistProps) => {
  const [collapsed, setCollapsed] = useState(false);

  useEffect(() => {
    try {
      if (localStorage.getItem(PLAN_CHECKLIST_COLLAPSED_KEY) === "1") {
        queueMicrotask(() => setCollapsed(true));
      }
    } catch {
      /* localStorage 不可用 (隐私模式等) 时静默用默认 */
    }
  }, []);

  const toggle = useCallback(() => {
    const next = !collapsed;
    setCollapsed(next);
    try {
      localStorage.setItem(PLAN_CHECKLIST_COLLAPSED_KEY, next ? "1" : "0");
    } catch {
      /* 忽略写入失败 */
    }
  }, [collapsed]);

  if (todos.length === 0) return null;
  const whole = wholeStatusOf(todos, active);
  const doneCount = todos.filter((t) => t.status === "done").length;
  const counter = `${doneCount} / ${todos.length}`;
  const current = todos.find((t) => t.status === "in_progress");
  // 折叠行永远带一步的名字: 跑着是当前步, 做完了是最后一步, 不留光秃秃的计数
  const headline = (current ?? todos[todos.length - 1]).title;

  return (
    <Collapsible
      open={!collapsed}
      onOpenChange={toggle}
      className={cn(CARD_SURFACE, "overflow-hidden")}
    >
      <CollapsibleTrigger
        data-testid="plan-checklist-toggle"
        className={cn(FLUSH_ROW_INTERACTIVE, "block w-full text-left")}
      >
        <div data-testid="plan-progress" className="flex gap-1 px-3.5 pt-3">
          {todos.map((todo) => (
            <span
              key={todo.title}
              className={cn("h-[3px] flex-1 rounded-full", segmentClass(todo.status, whole))}
            />
          ))}
        </div>
        {collapsed ? (
          <div className="flex items-center gap-2.5 px-3.5 pt-2.5 pb-3">
            <StatusIcon status={current ? "in_progress" : "done"} active={active} />
            <span
              className={cn(
                "min-w-0 flex-1 truncate text-ui leading-[22px] font-medium",
                whole === "done" ? "text-muted-foreground" : "text-foreground",
              )}
            >
              {headline}
            </span>
            <span className="text-caption text-ink-4 tabular-nums">{counter}</span>
            <span className="flex items-center gap-0.5 text-caption text-ink-4">
              展开
              <CollapsibleChevron strokeWidth={1.8} />
            </span>
          </div>
        ) : (
          <div className="flex items-center gap-2 px-3.5 pt-2.5 pb-2">
            <span className="text-caption font-medium tracking-wide text-ink-2">计划清单</span>
            <span className="text-caption text-ink-4 tabular-nums">{counter}</span>
            <span className="flex-1" />
            <WholeStatusLabel whole={whole} />
            <span className="flex items-center gap-0.5 text-caption text-ink-4">
              收起
              <CollapsibleChevron strokeWidth={1.8} />
            </span>
          </div>
        )}
      </CollapsibleTrigger>
      <CollapsiblePanel>
        <ol className="max-h-[40vh] overflow-y-auto border-t border-border px-2 pt-1.5 pb-2">
          {todos.map((todo, i) => {
            const focus = todo.status === "in_progress";
            const last = i === todos.length - 1;
            return (
              <li
                key={todo.title}
                className={cn("flex gap-2.5 rounded-md px-2", focus && "bg-surface-2")}
              >
                {/* 轨道: 首行顶端留空, 末行不画下段; 9px 上段让 16px 图标对齐 22px 行高的第一行 */}
                <span className="flex w-4 shrink-0 flex-col items-center">
                  <span
                    className={cn("h-[9px] w-0.5", i > 0 && railClass(todos[i - 1].status === "done"))}
                  />
                  <StatusIcon status={todo.status} active={active} />
                  {!last && (
                    <span className={cn("w-0.5 flex-1", railClass(todo.status === "done"))} />
                  )}
                </span>
                <span
                  className={cn(
                    "min-w-0 flex-1 py-1.5 text-ui leading-[22px]",
                    titleClass(todo.status),
                  )}
                >
                  {todo.title}
                </span>
              </li>
            );
          })}
        </ol>
      </CollapsiblePanel>
    </Collapsible>
  );
};