import { useState } from "react";
import { Form, Link, redirect, useActionData } from "react-router";
import type { ActionFunctionArgs } from "react-router";
import { createBandList, getIpAddress, type ListEntryInput } from "~/lib/db.server";

export async function action({ request }: ActionFunctionArgs) {
  const fd = await request.formData();
  const title = (fd.get("title") as string).trim();
  const slug = (fd.get("slug") as string).trim();
  const description = (fd.get("description") as string).trim();
  const message = (fd.get("message") as string).trim();
  const entries: ListEntryInput[] = JSON.parse((fd.get("entries") as string) || "[]");

  const errors: Record<string, string> = {};
  if (!title) errors.title = "必須です";
  if (!slug) errors.slug = "必須です";
  if (!message) errors.message = "必須です";
  if (Object.keys(errors).length > 0) return { errors };

  const id = crypto.randomUUID();
  try {
    createBandList({ id, slug, title, description, entries, message, ip_address: getIpAddress(request) });
  } catch (e) {
    if (e instanceof Error && e.message.includes("UNIQUE constraint failed: lists.slug")) {
      return { errors: { slug: "このslugは既に使用されています" } };
    }
    throw e;
  }
  return redirect(`/lists/of/${id}`);
}

function toSlug(s: string) {
  return s.trim().toLowerCase().replace(/\s+/g, "-").replace(/[^\w぀-ヿ一-鿿＀-￯-]/g, "").replace(/^-+|-+$/g, "");
}

type EntryRow = { key: string; band_name: string; note: string };

export default function ListNew() {
  const actionData = useActionData<typeof action>();
  const errors = actionData?.errors ?? {};

  const [title, setTitle] = useState("");
  const [slug, setSlug] = useState("");
  const [slugManual, setSlugManual] = useState(false);
  const [description, setDescription] = useState("");
  const [entries, setEntries] = useState<EntryRow[]>([]);

  function addEntry() {
    setEntries((prev) => [...prev, { key: crypto.randomUUID(), band_name: "", note: "" }]);
  }

  function removeEntry(key: string) {
    setEntries((prev) => prev.filter((e) => e.key !== key));
  }

  function updateEntry(key: string, field: "band_name" | "note", value: string) {
    setEntries((prev) => prev.map((e) => e.key === key ? { ...e, [field]: value } : e));
  }

  return (
    <main>
      <div className="page-header">
        <Link to="/lists" className="back">←</Link>
        <h1>New List</h1>
      </div>

      <Form method="post">
        <input type="hidden" name="entries" value={JSON.stringify(entries.map(({ band_name, note }) => ({ band_name, note })))} />

        <div>
          <label>タイトル <span className="req">*</span></label>
          <input
            name="title"
            value={title}
            onChange={(e) => { setTitle(e.target.value); if (!slugManual) setSlug(toSlug(e.target.value)); }}
          />
          {errors.title && <p className="error">{errors.title}</p>}
        </div>

        <div>
          <label>Slug <span className="req">*</span></label>
          <input
            name="slug"
            value={slug}
            onChange={(e) => { setSlugManual(true); setSlug(e.target.value); }}
            className="mono"
          />
          {errors.slug && <p className="error">{errors.slug}</p>}
        </div>

        <div>
          <label>説明</label>
          <input name="description" value={description} onChange={(e) => setDescription(e.target.value)} />
        </div>

        <div>
          <label>エントリ</label>
          <div>
            {entries.map((entry) => (
              <div key={entry.key} className="entry-row">
                <input
                  className="band-input"
                  value={entry.band_name}
                  onChange={(e) => updateEntry(entry.key, "band_name", e.target.value)}
                  placeholder="バンド名"
                />
                <input
                  className="note-input"
                  value={entry.note}
                  onChange={(e) => updateEntry(entry.key, "note", e.target.value)}
                  placeholder="メモ"
                />
                <button type="button" className="btn-icon" onClick={() => removeEntry(entry.key)}>×</button>
              </div>
            ))}
          </div>
          <button type="button" className="btn-text" onClick={addEntry}>+ エントリを追加</button>
        </div>

        <div>
          <label>更新メッセージ <span className="req">*</span></label>
          <input name="message" placeholder="例: 初回作成" />
          {errors.message && <p className="error">{errors.message}</p>}
        </div>

        <div className="actions">
          <button type="submit">作成</button>
          <Link to="/lists" className="btn">キャンセル</Link>
        </div>
      </Form>
    </main>
  );
}