import { useState, useMemo, memo } from 'react';
import {
  Package,
  User,
  Folder,
  RefreshCw,
  ChevronDown,
  ChevronRight,
  BookOpen,
} from 'lucide-react';
import type { SkillSummary } from '../../types/protocol';

/* ── types ────────────────────────────────────────────── */

interface SkillListProps {
  skills: SkillSummary[];
  onRefresh: () => void;
}

interface SourceConfig {
  label: string;
  icon: typeof Package;
  accent: string;
}

const SOURCE_CONFIG: Record<string, SourceConfig> = {
  user: { label: '用户技能', icon: User, accent: 'text-[var(--accent-cyan)]' },
  useragent: { label: '用户 Agent', icon: User, accent: 'text-[var(--accent-cyan)]' },
  useropenclaw: { label: '用户 OpenClaw', icon: User, accent: 'text-[var(--accent-cyan)]' },
  project: { label: '项目技能', icon: Folder, accent: 'text-[var(--accent-amber)]' },
  projectagent: { label: '项目 Agent', icon: Folder, accent: 'text-[var(--accent-amber)]' },
  projectopenclaw: { label: '项目 OpenClaw', icon: Folder, accent: 'text-[var(--accent-amber)]' },
};

function sourceConfig(source: string): SourceConfig {
  return (
    SOURCE_CONFIG[source] ?? {
      label: source,
      icon: Package,
      accent: 'text-[var(--text-secondary)]',
    }
  );
}

/* ── Section header ────────────────────────────────────── */

function SectionHeader({
  config,
  count,
  isCollapsed,
  onClick,
}: {
  config: SourceConfig;
  count: number;
  isCollapsed: boolean;
  onClick: () => void;
}) {
  const Icon = config.icon;
  return (
    <button
      onClick={onClick}
      className="sticky top-0 z-10 group flex items-center gap-2 w-full py-1.5 rounded-lg transition-colors hover:bg-[var(--overlay-hover)] bg-[var(--bg-secondary)]/90 backdrop-blur-sm -mx-3 px-3"
    >
      {isCollapsed ? (
        <ChevronRight className="h-3 w-3 text-[var(--text-muted)]" />
      ) : (
        <ChevronDown className="h-3 w-3 text-[var(--text-muted)]" />
      )}
      <div
        className={`flex items-center justify-center w-5 h-5 rounded-md bg-[var(--overlay-hover)] ${config.accent}`}
      >
        <Icon className="h-3 w-3" />
      </div>
      <span className="text-xs font-semibold text-[var(--text-primary)] tracking-tight">
        {config.label}
      </span>
      <span className="text-[10px] text-[var(--text-muted)] font-mono tabular-nums ml-auto">
        {count}
      </span>
    </button>
  );
}

/* ── Skill card ────────────────────────────────────────── */

function SkillCard({ skill, config }: { skill: SkillSummary; config: SourceConfig }) {
  return (
    <div className="group rounded-lg bg-[var(--overlay-hover)] border border-[var(--border-color)] overflow-hidden transition-all duration-200 hover:border-[var(--border-accent)]">
      <div className="px-3 py-2.5">
        <span className={`text-[10px] font-mono uppercase tracking-wider ${config.accent}`}>
          {skill.name}
        </span>
        <p className="text-sm text-[var(--text-secondary)] leading-relaxed mt-1">
          {skill.description}
        </p>
      </div>
    </div>
  );
}

/* ── main component ────────────────────────────────────── */

// memo：props 全部稳定（skills 仅在刷新时换引用、onRefresh 为 useCallback），
// 主视图流式期间 App 每帧重渲染时跳过面板重渲染与分组/排序重算。
export const SkillList = memo(function SkillList({ skills, onRefresh }: SkillListProps) {
  const [collapsed, setCollapsed] = useState<Set<string>>(() => {
    try {
      const s = localStorage.getItem('picobot-skill-collapsed');
      return s ? new Set(JSON.parse(s)) : new Set();
    } catch (_) {
      return new Set();
    }
  });

  const toggle = (source: string) => {
    setCollapsed((prev) => {
      const next = new Set(prev);
      if (next.has(source)) {
        next.delete(source);
      } else {
        next.add(source);
      }
      localStorage.setItem('picobot-skill-collapsed', JSON.stringify([...next]));
      return next;
    });
  };

  // skills 引用未变时跳过分组/排序重算（流式期间 App 每帧重渲染）
  const { grouped, sorted } = useMemo(() => {
    const grouped = new Map<string, SkillSummary[]>();
    for (const s of skills) {
      const l = grouped.get(s.source) || [];
      l.push(s);
      grouped.set(s.source, l);
    }

    const order = [
      'user',
      'useragent',
      'useropenclaw',
      'project',
      'projectagent',
      'projectopenclaw',
    ];
    const sorted = Array.from(grouped.keys()).sort((a, b) => {
      const ai = order.indexOf(a);
      const bi = order.indexOf(b);
      if (ai !== -1 && bi !== -1) return ai - bi;
      if (ai !== -1) return -1;
      if (bi !== -1) return 1;
      return a.localeCompare(b);
    });
    return { grouped, sorted };
  }, [skills]);

  return (
    <div className="flex h-full flex-col">
      {/* title bar */}
      <div className="shrink-0 border-b border-[var(--border-color)] px-4 py-3 flex items-center gap-2.5">
        <div className="flex items-center justify-center w-6 h-6 rounded-lg bg-[var(--accent-cyan)]/10">
          <BookOpen className="h-3.5 w-3.5 text-[var(--accent-cyan)]" />
        </div>
        <span className="text-sm font-bold text-[var(--text-primary)] tracking-tight">技能</span>
        {skills.length > 0 && (
          <span className="text-[11px] font-mono text-[var(--text-muted)] tabular-nums ml-0.5">
            {skills.length}
          </span>
        )}
        <div className="ml-auto flex items-center gap-0.5">
          <button
            onClick={onRefresh}
            className="p-1.5 rounded-lg hover:bg-[var(--overlay-hover)] text-[var(--text-muted)] hover:text-[var(--accent-cyan)] transition-colors"
            title="刷新"
          >
            <RefreshCw className="h-3.5 w-3.5" />
          </button>
        </div>
      </div>

      {/* empty */}
      {skills.length === 0 && (
        <div className="flex flex-1 items-center justify-center p-8">
          <div className="text-center select-none">
            <div className="relative inline-block mb-5">
              <div className="absolute inset-0 rounded-full bg-[var(--accent-cyan)]/10 blur-xl animate-pulse" />
              <BookOpen className="relative h-12 w-12 text-[var(--accent-cyan)]/25" />
            </div>
            <p className="text-sm text-[var(--text-muted)] leading-relaxed">
              暂无可用技能
              <br />在 .picobot/skills/ 目录下添加 SKILL.md 文件
            </p>
          </div>
        </div>
      )}

      {/* list */}
      {skills.length > 0 && (
        <div className="flex-1 overflow-y-auto px-3 pt-0 pb-2 space-y-3">
          {sorted.map((source) => {
            const cfg = sourceConfig(source);
            const items = grouped.get(source)!;
            const closed = collapsed.has(source);
            return (
              <div key={source}>
                <SectionHeader
                  config={cfg}
                  count={items.length}
                  isCollapsed={closed}
                  onClick={() => toggle(source)}
                />
                {!closed && (
                  <div className="mt-1.5 space-y-1.5">
                    {items.map((s) => (
                      <SkillCard key={s.name} skill={s} config={cfg} />
                    ))}
                  </div>
                )}
              </div>
            );
          })}
        </div>
      )}
    </div>
  );
});