"use client";

import { useCallback, useState } from "react";

import { api } from "@/lib/api/client";
import { useToast } from "@/components/Toast";
import type { RuleView } from "@/lib/api/types";
import { buildRuleCreateRequest, hasUsableContent, type RuleLevel } from "./rules";

export interface UseRules {
  items: RuleView[];
  busy: boolean;
  // 新增一条规则（乐观追加 + 失败回滚 + Toast）。
  add: (
    projectId: string,
    level: RuleLevel,
    content: string,
  ) => Promise<boolean>;
}

// 规则页（UX §7）：列出 + 新增规则。乐观追加，失败回滚（仿 useForeshadow）。
export function useRules(initial: RuleView[]): UseRules {
  const [items, setItems] = useState<RuleView[]>(initial);
  const [busy, setBusy] = useState(false);
  const toast = useToast();

  const add = useCallback<UseRules["add"]>(
    async (projectId, level, content) => {
      if (!hasUsableContent(content)) {
        toast("请填写规则正文。", "error");
        return false;
      }
      const snapshot = items;
      const optimistic: RuleView = { level, content: content.trim() };
      setItems((prev) => [...prev, optimistic]);
      setBusy(true);
      try {
        const { data, error } = await api.POST(
          "/projects/{project_id}/rules",
          {
            params: { path: { project_id: projectId } },
            body: buildRuleCreateRequest(level, content),
          },
        );
        if (error || !data) {
          setItems(snapshot); // 回滚
          toast("新增规则失败，请稍后重试。", "error");
          return false;
        }
        // 用服务端权威行替换乐观行（去掉乐观项、追加返回项）。
        setItems((prev) => [...prev.slice(0, snapshot.length), data]);
        toast("已新增规则", "success");
        return true;
      } finally {
        setBusy(false);
      }
    },
    [items, toast],
  );

  return { items, busy, add };
}