'use client';

import { useEffect, useRef, useState } from 'react';
import { Sparkles, Loader2, AlertCircle, RotateCw, Eye } from 'lucide-react';
import { appendPlanLog } from '@/lib/version-plan';
import type { VersionPlan } from '@/lib/version-plan';
import type { VersionWithContext } from '@/lib/derive';
import { useVersionPlanStore } from '@/stores/useVersionPlanStore';
import { useRequirementStore } from '@/stores/useRequirementStore';
import { useAuthStore } from '@/stores/useAuthStore';
import { useDevTaskStore } from '@/stores/useDevTaskStore';
import { useTestCaseStore } from '@/stores/useTestCaseStore';
import { useTaskCategoryStore } from '@/stores/useTaskCategoryStore';
import { api } from '@/lib/api';
import { filterDuplicateDecomposeDrafts } from '@/lib/ai-decompose-dedupe';
import { filterDecomposeResultByTarget } from '@/lib/ai-decompose-target';
import {
  aiDecomposeSessionStore,
  getAiDecomposeButtonMode,
  type AiDecomposeCompletedPayload,
} from '@/lib/ai-decompose-session';
import { DecomposeReportModal } from './DecomposeReportModal';
import type {
  AgentDecomposeTarget,
  AgentDecomposeRequest,
  AgentDecomposeResponse,
  AgentDecomposeError,
} from '@ftb/shared';

interface Props {
  plan: VersionPlan;
  version: VersionWithContext;
}

/** in_progress 视为"卡死"的阈值（秒）— 超过这个时间，按钮允许重新点击 */
const STUCK_THRESHOLD_SEC = 240;
const DECOMPOSE_TARGETS: AgentDecomposeTarget[] = ['dev_tasks', 'test_cases'];

function formatElapsed(sec: number): string {
  if (sec < 60) return `${sec}s`;
  const m = Math.floor(sec / 60);
  const s = sec % 60;
  return `${m}m${s}s`;
}

export function AiDecomposeButton({ plan, version }: Props) {
  const { updatePlan } = useVersionPlanStore();
  const { requirements } = useRequirementStore();
  const devTasks = useDevTaskStore((s) => s.tasks);
  const testCases = useTestCaseStore((s) => s.testCases);
  const categories = useTaskCategoryStore((s) => s.categories);
  const user = useAuthStore((s) => s.user);

  const [viewingTarget, setViewingTarget] = useState<AgentDecomposeTarget | null>(null);
  const [tick, setTick] = useState(() => Date.now());
  const [, bumpSessionVersion] = useState(0);
  const mountedRef = useRef(false);

  // plan 上的状态（持久化在 localStorage）
  const persistStatus = plan.aiDecomposeStatus;
  const persistError = plan.aiDecomposeError;
  const persistAt = plan.aiDecomposeAt;
  const persistTarget = plan.aiDecomposeTarget;

  useEffect(() => {
    mountedRef.current = true;
    const unsubscribe = aiDecomposeSessionStore.subscribe(() => bumpSessionVersion((value) => value + 1));
    return () => {
      mountedRef.current = false;
      unsubscribe();
    };
  }, []);

  const getSession = (target: AgentDecomposeTarget) => aiDecomposeSessionStore.get(plan.id, target);
  const hasSessionGenerating = DECOMPOSE_TARGETS.some((target) => getSession(target).status === 'generating');

  const persistedElapsedSec = (() => {
    if (persistStatus === 'in_progress' && persistAt) {
      const start = new Date(persistAt).getTime();
      return Math.max(0, Math.floor((tick - start) / 1000));
    }
    return 0;
  })();

  const isStaleInProgress =
    persistStatus === 'in_progress' && !hasSessionGenerating && persistedElapsedSec > STUCK_THRESHOLD_SEC;
  const hasPersistedInProgress = persistStatus === 'in_progress' && !isStaleInProgress;
  const isInProgress = hasSessionGenerating || hasPersistedInProgress;

  const currentError = DECOMPOSE_TARGETS.map((target) => getSession(target))
    .find((session) => session.status === 'error');
  const visibleError = currentError?.status === 'error' ? currentError.error : persistStatus === 'error' ? persistError : undefined;

  // tick 每秒更新一次，让"已用时"实时跳
  useEffect(() => {
    if (!isInProgress) return;
    const id = setInterval(() => setTick(Date.now()), 1000);
    return () => clearInterval(id);
  }, [isInProgress]);

  const linkedReqs = requirements
    .filter((r) => r.versionId === version.id)
    .map((r) => ({
      id: r.id,
      code: r.code,
      title: r.title,
      description: r.description,
    }));

  const targetText = (target: AgentDecomposeTarget) => {
    if (target === 'dev_tasks') return '开发任务';
    if (target === 'test_cases') return '测试用例';
    return '任务和用例';
  };

  const appendAiLog = (
    target: AgentDecomposeTarget,
    status: 'started' | 'completed' | 'error',
    detail?: string,
  ) => {
    const currentPlan = useVersionPlanStore.getState().plans.find((item) => item.id === plan.id) ?? plan;
    const statusText = status === 'started' ? '已触发' : status === 'completed' ? '已完成' : '失败';
    return appendPlanLog(currentPlan, {
      type: 'ai_decompose',
      actor: user?.name ?? plan.owner,
      title: `AI 拆解${targetText(target)}${statusText}`,
      detail,
      aiTarget: target,
      aiStatus: status,
    });
  };

  const handleClick = async (target: AgentDecomposeTarget) => {
    const session = getSession(target);
    if (session.status === 'completed') {
      setViewingTarget(target);
      return;
    }

    if (hasSessionGenerating) return;
    // 即便 persistStatus 是 in_progress，只要超过阈值就允许重新点
    if (persistStatus === 'in_progress' && !isStaleInProgress) return;

    setTick(Date.now());

    const run = async (): Promise<AiDecomposeCompletedPayload> => {
      updatePlan(plan.id, {
        aiDecomposeStatus: 'in_progress',
        aiDecomposeBy: user?.name,
        aiDecomposeAt: new Date().toISOString(),
        aiDecomposeTarget: target,
        aiDecomposeError: undefined,
        logs: appendAiLog(target, 'started'),
      });

      const members = (version.members ?? []).map((m) => ({
        name: m.name,
        role: m.role,
      }));

      const payload: AgentDecomposeRequest = {
        prototypeUrl: plan.resultUrl || '',
        requirements: linkedReqs,
        members,
        versionId: version.id,
        planId: plan.id,
        target,
      };

      const resp = await api.postRaw<AgentDecomposeResponse | AgentDecomposeError>(
        '/ai/decompose',
        payload,
        300000,
      );

      if (!resp.ok) {
        throw new Error(resp.error);
      }

      const targetFilteredResult = filterDecomposeResultByTarget(resp.result, target);
      const requirementIdSet = new Set(linkedReqs.map((req) => req.id));
      const deduped = filterDuplicateDecomposeDrafts(targetFilteredResult, {
        existingDevTasks: devTasks.filter((task) => task.versionId === version.id || (!task.versionId && requirementIdSet.has(task.requirementId))),
        existingTestCases: testCases.filter((testCase) => testCase.versionId === version.id),
        categories,
        requirements: linkedReqs,
      });
      const result = { ...resp, result: filterDecomposeResultByTarget(deduped.result, target) };

      updatePlan(plan.id, {
        aiDecomposeStatus: 'completed',
        aiDecomposeTarget: target,
        aiDecomposeError: undefined,
        logs: appendAiLog(
          target,
          'completed',
          `生成开发任务 ${deduped.result.devTaskDrafts.length} 条，测试用例 ${deduped.result.testCaseDrafts.length} 条。已过滤重复开发任务 ${deduped.removedDevTaskCount} 条，重复测试用例 ${deduped.removedTestCaseCount} 条。`,
        ),
      });

      return {
        result,
        dedupeSummary: {
          removedDevTaskCount: deduped.removedDevTaskCount,
          removedTestCaseCount: deduped.removedTestCaseCount,
        },
      };
    };

    try {
      await aiDecomposeSessionStore.start(plan.id, target, run);
      if (mountedRef.current) setViewingTarget(target);
    } catch (e: any) {
      const msg = e?.message || '调用 AI 服务失败';
      updatePlan(plan.id, {
        aiDecomposeStatus: 'error',
        aiDecomposeTarget: target,
        aiDecomposeError: msg,
        logs: appendAiLog(target, 'error', msg),
      });
    }
  };

  const handleResultReviewed = (target: AgentDecomposeTarget) => {
    aiDecomposeSessionStore.markReviewed(plan.id, target);
    setViewingTarget(null);
  };

  if (plan.type !== 'product' || plan.status !== 'completed' || !plan.resultUrl) {
    return null;
  }

  const viewingSession = viewingTarget ? getSession(viewingTarget) : null;

  return (
    <>
      <span className="inline-flex items-center gap-1.5">
        {DECOMPOSE_TARGETS.map((target) => {
          const session = getSession(target);
          const mode = getAiDecomposeButtonMode(session);
          const showSpinner = mode === 'generating' || (hasPersistedInProgress && persistTarget === target);
          const targetElapsedSec =
            session.status === 'generating'
              ? Math.max(0, Math.floor((tick - session.startedAt) / 1000))
              : persistedElapsedSec;
          const targetHasError =
            mode === 'retry' || (persistStatus === 'error' && (persistTarget === target || !persistTarget));
          const targetErrorMessage = session.status === 'error' ? session.error : persistError || '未知错误';
          const label =
            mode === 'view_result'
              ? `查看${targetText(target)}结果`
              : persistStatus === 'completed' && persistTarget === target
                ? `重新拆解${targetText(target)}`
                : `AI 拆解${targetText(target)}`;
          return (
            <button
              type="button"
              key={target}
              onClick={() => handleClick(target)}
              disabled={isInProgress && mode !== 'view_result'}
              className={`inline-flex items-center gap-1 rounded-md border px-2 py-1 text-[11px] font-medium disabled:cursor-not-allowed disabled:opacity-70 ${
                targetHasError
                  ? 'border-red-200 bg-red-50 text-red-700 hover:bg-red-100'
                  : 'border-purple-200 bg-purple-50 text-purple-700 hover:bg-purple-100'
              }`}
              title={
                targetHasError
                  ? `上次失败：${targetErrorMessage}（点击重试${targetText(target)}）`
                  : mode === 'view_result'
                    ? `查看本次 AI 拆解${targetText(target)}结果`
                    : persistStatus === 'completed' && persistTarget === target
                      ? `此前已拆解过，再次点击会重新拆解${targetText(target)}`
                    : `使用 AI 把原型 + 关联需求拆解成${targetText(target)}`
              }
            >
              {showSpinner ? (
                <>
                  <Loader2 className="h-3 w-3 animate-spin" />
                  拆解中 {formatElapsed(targetElapsedSec)}
                </>
              ) : targetHasError ? (
                <>
                  <RotateCw className="h-3 w-3" />
                  重试{targetText(target)}
                </>
              ) : mode === 'view_result' ? (
                <>
                  <Eye className="h-3 w-3" />
                  {label}
                </>
              ) : (
                <>
                  <Sparkles className="h-3 w-3" />
                  {label}
                </>
              )}
            </button>
          );
        })}
      </span>

      {/* 错误信息：在按钮旁悬浮显示 */}
      {visibleError && (
        <span className="ml-1 inline-flex items-center gap-1 text-[11px] text-red-600 max-w-[260px]" title={visibleError}>
          <AlertCircle className="h-3 w-3 shrink-0" />
          <span className="truncate">{visibleError}</span>
        </span>
      )}

      {/* 卡死提示：persistStatus 是 in_progress 但已超时 */}
      {isStaleInProgress && (
        <span className="ml-1 text-[11px] text-amber-600" title="上次拆解记录残留，点击按钮重新拆解">
          上次未完成（{formatElapsed(persistedElapsedSec)}）
        </span>
      )}

      {viewingTarget && viewingSession?.status === 'completed' && (
        <DecomposeReportModal
          result={viewingSession.payload.result}
          version={version}
          plan={plan}
          requirements={linkedReqs}
          target={viewingTarget}
          dedupeSummary={viewingSession.payload.dedupeSummary}
          onClose={() => setViewingTarget(null)}
          onAdopted={() => handleResultReviewed(viewingTarget)}
          onRejected={() => handleResultReviewed(viewingTarget)}
        />
      )}
    </>
  );
}