'use client';

import { useState, useMemo } from 'react';
import { X, AlertTriangle, Link2, ChevronRight, Clock, User, Tag, Play, Trash2, ArrowRightLeft, CalendarRange } from 'lucide-react';
import { StatusBadge } from './StatusBadge';
import { CategoryChip } from './CategoryChip';
import { useDevTaskStore } from '@/stores/useDevTaskStore';
import { useTaskCategoryStore } from '@/stores/useTaskCategoryStore';
import { useRequirementStore } from '@/stores/useRequirementStore';
import { useMemberStore } from '@/stores/useMemberStore';
import {
  ALLOWED_TRANSITIONS,
  DEV_TASK_STATUS_LABEL,
  DEV_TASK_STATUS_COLOR,
  formatHours,
  getEstimateHours,
  getActualHours,
} from '@/lib/dev-task';
import { needsDelayReason } from '@/lib/dev-task-transitions';
import { formatShortTime } from '@/lib/work-hours';
import type { DevTaskStatus } from '@/lib/dev-task';

interface Props {
  taskId: string;
  allTaskIds: string[];
  onClose: () => void;
  contextLabel?: string;
}

export function DevTaskDetailDrawer({ taskId, allTaskIds, onClose, contextLabel }: Props) {
  const { tasks, changeStatus, setBlocked, deleteTask, updateTask } = useDevTaskStore();
  const { categories } = useTaskCategoryStore();
  const { requirements } = useRequirementStore();
  const { members } = useMemberStore();
  const [showTransfer, setShowTransfer] = useState(false);
  const [transferTo, setTransferTo] = useState('');
  const [showDelayInput, setShowDelayInput] = useState(false);
  const [delayReason, setDelayReason] = useState('');

  const task = tasks.find((t) => t.id === taskId);
  if (!task) return null;

  const category = categories.find((c) => c.id === task.categoryId);
  const requirement = requirements.find((r) => r.id === task.requirementId);
  const allTasks = tasks.filter((t) => allTaskIds.includes(t.id));
  const predecessors = (task.predecessorIds || []).map((id) => allTasks.find((t) => t.id === id)).filter(Boolean);
  const nextStatuses = ALLOWED_TRANSITIONS[task.status] || [];

  const [blockReason, setBlockReason] = useState(task.blockReason || '');
  const [showBlockInput, setShowBlockInput] = useState(false);

  const estimate = useMemo(() => getEstimateHours(task), [task]);
  const executorEstimate = typeof task.estimateHours === 'number' && task.estimateHours > 0 ? task.estimateHours : undefined;
  const aiEstimate = typeof task.aiEstimateHours === 'number' && task.aiEstimateHours > 0 ? task.aiEstimateHours : undefined;
  const actual = useMemo(() => getActualHours(task), [task]);
  const overrun = actual > estimate && estimate > 0;
  const requireDelay = task.status === 'todo' && needsDelayReason(task);

  const handleTransition = (to: DevTaskStatus) => {
    if (to === 'in_progress' && requireDelay && !showDelayInput) {
      setShowDelayInput(true);
      return;
    }
    const opts = to === 'in_progress' && delayReason.trim()
      ? { delayReason: delayReason.trim() }
      : undefined;
    const result = changeStatus(task.id, to, opts);
    if (!result.ok) {
      alert(result.message);
      return;
    }
    if (to === 'in_progress') {
      setShowDelayInput(false);
      setDelayReason('');
    }
  };

  const handleBlock = () => {
    if (!blockReason.trim()) return;
    setBlocked(task.id, true, blockReason.trim());
    setShowBlockInput(false);
  };

  const handleUnblock = () => {
    setBlocked(task.id, false);
    setBlockReason('');
  };

  return (
    <div className="fixed inset-0 z-50 flex justify-end" onClick={onClose}>
      <div className="w-full max-w-md h-full bg-[var(--bg)] border-l border-[var(--line)] shadow-2xl flex flex-col" onClick={(e) => e.stopPropagation()}>
        {contextLabel && (
          <div className="px-5 py-2 border-b border-[var(--line)] bg-[var(--bg-subtle)] shrink-0">
            <span className="text-[11px] text-[var(--ink-muted)]">{contextLabel}</span>
          </div>
        )}
        <div className="flex items-center justify-between h-14 px-5 border-b border-[var(--line)] bg-[var(--bg-card)] shrink-0">
          <div className="flex items-center gap-2">
            <span className="text-[12px] font-mono text-[var(--ink-muted)]">{task.taskNo}</span>
            <span className="text-[14px] font-semibold text-[var(--ink)] truncate max-w-[240px]">{task.title}</span>
          </div>
          <div className="flex items-center gap-1">
            {task.status !== 'submitted' && (
              <button onClick={() => setShowTransfer(!showTransfer)} className="p-1.5 rounded-lg hover:bg-blue-50 text-[var(--ink-muted)] hover:text-blue-500" title="转交"><ArrowRightLeft className="h-4 w-4" /></button>
            )}
            <button onClick={() => { if (confirm('确定删除此任务？')) { deleteTask(task.id); onClose(); } }} className="p-1.5 rounded-lg hover:bg-red-50 text-[var(--ink-muted)] hover:text-red-500" title="删除"><Trash2 className="h-4 w-4" /></button>
            <button onClick={onClose} className="p-1.5 rounded-lg hover:bg-[var(--bg-subtle)]"><X className="h-4 w-4 text-[var(--ink-muted)]" /></button>
          </div>
        </div>

        {showTransfer && (
          <div className="mx-5 mt-3 rounded-lg border border-[var(--line)] p-3 flex items-center gap-2">
            <span className="text-[11px] text-[var(--ink-muted)] shrink-0">转交给：</span>
            <select value={transferTo} onChange={(e) => setTransferTo(e.target.value)} className="h-7 flex-1 rounded-lg border border-[var(--line)] px-2 text-[12px] focus:border-[var(--accent)] focus:outline-none">
              <option value="">选择人员</option>
              {members.filter((m) => m.name !== task.assigneeId).map((m) => <option key={m.id} value={m.name}>{m.name}</option>)}
            </select>
            <button onClick={() => { if (transferTo) { updateTask(task.id, { assigneeId: transferTo }); setShowTransfer(false); setTransferTo(''); } }} disabled={!transferTo} className="h-7 px-2.5 rounded text-[11px] font-medium bg-blue-500 text-white disabled:opacity-50">确认</button>
            <button onClick={() => setShowTransfer(false)} className="h-7 px-2 text-[11px] text-[var(--ink-muted)]">取消</button>
          </div>
        )}

        <div className="flex-1 overflow-y-auto p-4 space-y-3">

          {requirement && (
            <div className="rounded-xl border border-[var(--line)] bg-[var(--bg-card)] p-3">
              <div className="text-[10px] text-[var(--ink-muted)] uppercase tracking-wide mb-1.5">关联需求</div>
              <div className="flex items-center gap-2">
                <Link2 className="h-3.5 w-3.5 text-[var(--accent)]" />
                <span className="text-[11px] font-mono text-[var(--ink-muted)]">{requirement.code}</span>
                <span className="text-[13px] text-[var(--ink)]">{requirement.title}</span>
              </div>
            </div>
          )}

          <div className="rounded-xl border border-[var(--line)] bg-[var(--bg-card)] p-4 space-y-3">
            <div className="text-[10px] text-[var(--ink-muted)] uppercase tracking-wide">状态 & 操作</div>
            <div className="flex items-center gap-3">
              <span className={`inline-flex items-center rounded-lg px-3 py-1.5 text-[13px] font-semibold ${DEV_TASK_STATUS_COLOR[task.status]}`}>
                {DEV_TASK_STATUS_LABEL[task.status]}
              </span>
              {task.isBlocked && (
                <span className="inline-flex items-center gap-1 text-[11px] text-red-600 bg-red-50 border border-red-200 px-2 py-1 rounded-lg">
                  <AlertTriangle className="h-3 w-3" />阻塞中
                </span>
              )}
              {requireDelay && (
                <span className="inline-flex items-center gap-1 text-[11px] text-orange-600 bg-orange-50 border border-orange-200 px-2 py-1 rounded-lg" title="已超过预计开始时间，开干需填延后原因">
                  <AlertTriangle className="h-3 w-3" />超期未开始
                </span>
              )}
            </div>

            {nextStatuses.length > 0 && !showDelayInput && (
              <div className="flex items-center gap-2 pt-1 flex-wrap">
                <ChevronRight className="h-3.5 w-3.5 text-[var(--ink-muted)]" />
                {nextStatuses.map((s) => (
                  <button key={s} onClick={() => handleTransition(s)} className="h-8 px-4 rounded-lg text-[12px] font-medium bg-[var(--accent)] text-white hover:bg-[var(--accent-hover)] transition-colors">
                    {DEV_TASK_STATUS_LABEL[s]}
                  </button>
                ))}
              </div>
            )}

            {showDelayInput && (
              <div className="rounded-lg border border-orange-200 bg-orange-50 p-3 space-y-2">
                <div className="flex items-center gap-1.5 text-[11px] text-orange-700">
                  <AlertTriangle className="h-3.5 w-3.5" />
                  已超过预计开始时间，请说明延后原因
                </div>
                <input value={delayReason} onChange={(e) => setDelayReason(e.target.value)} placeholder="延后原因（必填）" className="h-8 w-full rounded-md border border-orange-200 bg-white px-2 text-[12px] focus:border-orange-400 focus:outline-none" autoFocus />
                <div className="flex gap-2">
                  <button onClick={() => handleTransition('in_progress')} disabled={!delayReason.trim()} className="h-7 px-3 rounded text-[11px] font-medium bg-[var(--accent)] text-white disabled:opacity-50">开始开发</button>
                  <button onClick={() => { setShowDelayInput(false); setDelayReason(''); }} className="h-7 px-2 text-[11px] text-[var(--ink-muted)]">取消</button>
                </div>
              </div>
            )}

            <div className="pt-2 border-t border-[var(--line)]">
              {task.isBlocked ? (
                <div className="space-y-2">
                  <div className="flex items-start gap-1.5 text-[12px] text-red-600 bg-red-50 rounded-lg px-3 py-2">
                    <AlertTriangle className="h-3.5 w-3.5 shrink-0 mt-0.5" />
                    <span>{task.blockReason}</span>
                  </div>
                  <button onClick={handleUnblock} className="text-[11px] text-emerald-600 font-medium hover:underline">解除阻塞</button>
                </div>
              ) : (
                showBlockInput ? (
                  <div className="flex gap-2">
                    <input value={blockReason} onChange={(e) => setBlockReason(e.target.value)} onKeyDown={(e) => { if (e.key === 'Enter') handleBlock(); }} placeholder="阻塞原因" className="flex-1 h-8 rounded-lg border border-[var(--line)] px-3 text-[12px] focus:border-red-400 focus:outline-none" autoFocus />
                    <button onClick={handleBlock} disabled={!blockReason.trim()} className="h-8 px-3 rounded-lg text-[11px] font-medium bg-red-500 text-white disabled:opacity-50">确认</button>
                    <button onClick={() => setShowBlockInput(false)} className="h-8 px-2 text-[11px] text-[var(--ink-muted)]">取消</button>
                  </div>
                ) : (
                  <button onClick={() => setShowBlockInput(true)} className="text-[11px] text-red-500 font-medium hover:underline">标记阻塞</button>
                )
              )}
            </div>
          </div>

          <div className="rounded-xl border border-[var(--line)] bg-[var(--bg-card)] p-4">
            <div className="text-[10px] text-[var(--ink-muted)] uppercase tracking-wide mb-3 flex items-center gap-1.5"><CalendarRange className="h-3 w-3" />时间信息</div>
            <div className="grid grid-cols-2 gap-y-2.5 gap-x-4 text-[12px]">
              <div className="flex flex-col gap-0.5">
                <span className="text-[10px] text-[var(--ink-muted)]">预计开始</span>
                <span className="text-[var(--ink)] font-medium tabular-nums">{task.expectedStartAt ? formatShortTime(task.expectedStartAt) : '-'}</span>
              </div>
              <div className="flex flex-col gap-0.5">
                <span className="text-[10px] text-[var(--ink-muted)]">预计截止</span>
                <span className="text-[var(--ink)] font-medium tabular-nums">{task.expectedEndAt ? formatShortTime(task.expectedEndAt) : '-'}</span>
              </div>
              <div className="flex flex-col gap-0.5">
                <span className="text-[10px] text-[var(--ink-muted)]">实际开始</span>
                <span className="text-[var(--ink)] font-medium tabular-nums">{task.actualStartAt ? formatShortTime(task.actualStartAt) : '—'}</span>
              </div>
              <div className="flex flex-col gap-0.5">
                <span className="text-[10px] text-[var(--ink-muted)]">实际结束</span>
                <span className="text-[var(--ink)] font-medium tabular-nums">{task.actualEndAt ? formatShortTime(task.actualEndAt) : '—'}</span>
              </div>
              <div className="flex flex-col gap-0.5">
                <span className="text-[10px] text-[var(--ink-muted)]">AI 预估</span>
                <span className="text-[var(--ink)] font-medium tabular-nums">{aiEstimate ? formatHours(aiEstimate) : '—'}</span>
              </div>
              <div className="flex flex-col gap-0.5">
                <span className="text-[10px] text-[var(--ink-muted)]">执行预估</span>
                <span className="text-[var(--ink)] font-medium tabular-nums">{executorEstimate ? formatHours(executorEstimate) : '待负责人填写'}</span>
              </div>
              <div className="flex flex-col gap-0.5">
                <span className="text-[10px] text-[var(--ink-muted)]">实际耗时</span>
                <span className={`font-medium tabular-nums ${actual > 0 ? (overrun ? 'text-red-600' : (actual < estimate ? 'text-emerald-600' : 'text-[var(--ink)]')) : 'text-[var(--ink-muted)]'}`}>
                  {actual > 0 ? formatHours(actual) : '—'}
                  {task.actualStartAt && !task.actualEndAt && <span className="text-[10px] ml-1 text-[var(--ink-muted)]">进行中</span>}
                </span>
              </div>
            </div>
            {task.delayReason && (
              <div className="mt-3 pt-3 border-t border-[var(--line)] text-[11px] text-orange-700 bg-orange-50 rounded-lg px-3 py-2">
                <div className="flex items-start gap-1.5">
                  <AlertTriangle className="h-3 w-3 shrink-0 mt-0.5" />
                  <div><span className="font-medium">延后原因：</span>{task.delayReason}</div>
                </div>
              </div>
            )}
            {task.overdueVersionReason && (
              <div className="mt-2 text-[11px] text-orange-700 bg-orange-50 rounded-lg px-3 py-2">
                <span className="font-medium">超出版本截止原因：</span>{task.overdueVersionReason}
              </div>
            )}
          </div>

          <div className="rounded-xl border border-[var(--line)] bg-[var(--bg-card)] p-4">
            <div className="text-[10px] text-[var(--ink-muted)] uppercase tracking-wide mb-3">基本信息</div>
            <div className="grid grid-cols-2 gap-y-3 gap-x-4 text-[12px]">
              <div className="flex items-center gap-2">
                <Tag className="h-3 w-3 text-[var(--ink-muted)]" />
                <span className="text-[var(--ink-muted)]">类型</span>
                <CategoryChip category={category} />
              </div>
              <div className="flex items-center gap-2">
                <User className="h-3 w-3 text-[var(--ink-muted)]" />
                <span className="text-[var(--ink-muted)]">负责人</span>
                <span className="text-[var(--ink)] font-medium">{task.assigneeId}</span>
              </div>
              <div className="flex items-center gap-2">
                <span className="text-[var(--ink-muted)]">优先级</span>
                <span className="text-[var(--ink)] font-medium">{task.priority}</span>
              </div>
              <div className="flex items-center gap-2">
                <Clock className="h-3 w-3 text-[var(--ink-muted)]" />
                <span className="text-[var(--ink-muted)]">创建</span>
                <span className="text-[var(--ink)]">{formatShortTime(task.createdAt)}</span>
              </div>
            </div>
            {task.description && (
              <div className="mt-3 pt-3 border-t border-[var(--line)]">
                <p className="text-[12px] text-[var(--ink-soft)] leading-relaxed">{task.description}</p>
              </div>
            )}
          </div>

          {predecessors.length > 0 && (
            <div className="rounded-xl border border-[var(--line)] bg-[var(--bg-card)] p-4">
              <div className="text-[10px] text-[var(--ink-muted)] uppercase tracking-wide mb-2">前置任务</div>
              <div className="space-y-2">
                {predecessors.map((p: any) => (
                  <div key={p.id} className="flex items-center gap-2 text-[12px] px-2.5 py-1.5 rounded-lg bg-[var(--bg-subtle)]">
                    <Link2 className="h-3 w-3 text-[var(--ink-muted)]" />
                    <span className="font-mono text-[var(--ink-muted)]">{p.taskNo}</span>
                    <span className="text-[var(--ink)] flex-1 truncate">{p.title}</span>
                    <StatusBadge status={p.status} />
                  </div>
                ))}
              </div>
            </div>
          )}

        </div>
      </div>
    </div>
  );
}