import type { LucideIcon } from "lucide-react";
import { Blocks, Database, Pencil, ShieldCheck } from "lucide-react";

import { AppShell } from "@/components/AppShell";
import { Badge } from "@/components/ui/Badge";
import { Card } from "@/components/ui/Card";
import { EmptyState } from "@/components/ui/EmptyState";
import { PageHeader } from "@/components/ui/PageHeader";
import { SectionHeader } from "@/components/ui/SectionHeader";
import { StatusNote } from "@/components/ui/StatusNote";
import type { ProjectResponse, SkillView } from "@/lib/api/types";
import {
  groupByScope,
  scopeLabel,
  summarizeSkills,
  tierLabel,
} from "@/lib/skills/skills";

interface SkillsPageProps {
  project: ProjectResponse;
  skills: SkillView[];
}

// 技能库（UX §7）：只读注册表视图（name/scope/tier/reads/writes）。Server Component（纯读）。
export function SkillsPage({ project, skills }: SkillsPageProps) {
  const groups = groupByScope(skills);
  const summary = summarizeSkills(skills);

  return (
    <AppShell
      title={`〈${project.title}〉`}
      subtitle="技能库"
      projectId={project.id}
      activeNav="skills"
    >
      <div className="mx-auto flex max-w-6xl flex-col gap-6 p-6">
        <PageHeader
          title="技能库"
          description="声明式 Skill 注册表：每个技能声明能力档位与可读/写的表，越权产出会被丢弃并审计。"
        />
        <div className="grid gap-6 lg:grid-cols-[18rem_minmax(0,1fr)]">
          <aside className="flex flex-col gap-4 lg:sticky lg:top-[8rem] lg:self-start">
            <Card as="section" className="p-4">
              <SectionHeader
                title="注册表概览"
                description="按来源、档位和表权限汇总当前可用技能。"
              />
              <dl className="mt-4 grid grid-cols-3 gap-2 text-center">
                <div className="rounded border border-line bg-bg p-3">
                  <dt className="text-xs text-ink-soft">总数</dt>
                  <dd className="mt-1 font-serif text-2xl text-ink">
                    {summary.total}
                  </dd>
                </div>
                <div className="rounded border border-line bg-bg p-3">
                  <dt className="text-xs text-ink-soft">可写</dt>
                  <dd className="mt-1 font-serif text-2xl text-ink">
                    {summary.writableCount}
                  </dd>
                </div>
                <div className="rounded border border-line bg-bg p-3">
                  <dt className="text-xs text-ink-soft">只读</dt>
                  <dd className="mt-1 font-serif text-2xl text-ink">
                    {summary.readonlyCount}
                  </dd>
                </div>
              </dl>
              <div className="mt-4 flex flex-wrap gap-2">
                {summary.scopes.length > 0 ? (
                  summary.scopes.map((item) => (
                    <Badge key={item.key} variant="info">
                      {scopeLabel(item.key)} {item.count}
                    </Badge>
                  ))
                ) : (
                  <span className="text-xs text-ink-soft">暂无来源</span>
                )}
              </div>
            </Card>

            <Card as="section" className="p-4">
              <SectionHeader title="能力档位" />
              {summary.tiers.length > 0 ? (
                <ul className="mt-3 flex flex-col gap-2 text-sm">
                  {summary.tiers.map((item) => (
                    <li
                      key={item.key}
                      className="flex items-center justify-between border-b border-line/70 py-2 last:border-b-0"
                    >
                      <span className="text-ink">{tierLabel(item.key)}</span>
                      <span className="font-mono text-xs text-ink-soft">
                        {item.count}
                      </span>
                    </li>
                  ))}
                </ul>
              ) : (
                <p className="mt-3 text-sm text-ink-soft">暂无档位</p>
              )}
            </Card>

            <StatusNote title="写入边界" variant="info">
              <p className="text-sm leading-6">
                可写表：{formatTables(summary.writableTables)}
              </p>
              <p className="mt-1 text-xs leading-5 text-ink-soft">
                技能产出仍会经过表权限白名单；审稿与验收相关写入继续由人工确认流程收口。
              </p>
            </StatusNote>
          </aside>

          <div className="flex min-w-0 flex-col gap-5">
            {groups.length === 0 ? (
              <EmptyState
                icon={Blocks}
                title="暂无已注册技能"
                description="技能注册后会在这里按作用域展示能力档位、可读表与可写表。"
              />
            ) : (
              <>
                {groups.map((group) => (
                <section key={group.scope}>
                  <SectionHeader
                    title={scopeLabel(group.scope)}
                    description={`${group.skills.length} 个技能`}
                  />
                  <ul className="mt-3 grid gap-3">
                    {group.skills.map((skill) => (
                      <SkillListItem key={skill.name} skill={skill} />
                    ))}
                  </ul>
                </section>
                ))}
              </>
            )}
          </div>
        </div>
      </div>
    </AppShell>
  );
}

function SkillListItem({ skill }: { skill: SkillView }) {
  return (
    <li className="rounded border border-line bg-panel p-4 text-sm shadow-paper">
      <div className="flex flex-col gap-3 sm:flex-row sm:items-start sm:justify-between">
        <div className="min-w-0">
          <div className="flex flex-wrap items-center gap-2">
            <span className="break-all font-mono text-ink">{skill.name}</span>
            <Badge variant="info">{tierLabel(skill.tier)}</Badge>
            {skill.genre ? <Badge>{skill.genre}</Badge> : null}
          </div>
          <div className="mt-3 grid gap-2 text-xs text-ink-soft md:grid-cols-2">
            <TableLine
              icon={Database}
              label="读"
              tables={skill.reads ?? []}
            />
            <TableLine icon={Pencil} label="写" tables={skill.writes ?? []} />
          </div>
        </div>
        <div className="flex shrink-0 items-center gap-2 text-xs text-ink-soft">
          <ShieldCheck className="h-3.5 w-3.5" aria-hidden="true" />
          <span>
            {skill.writes && skill.writes.length > 0 ? "受控写入" : "只读"}
          </span>
        </div>
      </div>
    </li>
  );
}

function TableLine({
  icon: Icon,
  label,
  tables,
}: {
  icon: LucideIcon;
  label: string;
  tables: readonly string[];
}) {
  return (
    <span className="flex min-w-0 items-start gap-1.5">
      <Icon className="mt-0.5 h-3.5 w-3.5 shrink-0" aria-hidden="true" />
      <span className="shrink-0">{label}：</span>
      <span className="min-w-0 break-words">{formatTables(tables)}</span>
    </span>
  );
}

function formatTables(tables: readonly string[]): string {
  return tables.length > 0 ? tables.join("、") : "—";
}