import { useState } from "react";
import { Form, Link, redirect, useActionData, useLoaderData } from "react-router";
import type { ActionFunctionArgs } from "react-router";
import { createBand, getIpAddress, listArtists } from "~/lib/db.server";
import { ARTIST_ROLES, LINK_TYPES } from "~/lib/constants";

export function loader() {
  return { artists: listArtists() };
}

export async function action({ request }: ActionFunctionArgs) {
  const fd = await request.formData();
  const name = (fd.get("name") as string).trim();
  const slug = (fd.get("slug") as string).trim();
  const area = (fd.get("area") as string).trim() || null;
  const description = (fd.get("description") as string).trim() || null;
  const status = (fd.get("status") as string) || "active";
  const message = (fd.get("message") as string).trim();
  const links: { label: string; url: string }[] = JSON.parse(
    (fd.get("links") as string) || "[]"
  );
  const artists: { id: string; role: string | null }[] = JSON.parse(
    (fd.get("artists") as string) || "[]"
  );

  const errors: Record<string, string> = {};
  if (!name) errors.name = "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 {
    createBand({ id, slug, name, area, description, status, links, artists, message, ip_address: getIpAddress(request) });
  } catch (e) {
    if (e instanceof Error && e.message.includes("UNIQUE constraint failed: bands.slug")) {
      return { errors: { slug: "このslugは既に使用されています" } };
    }
    throw e;
  }
  return redirect(`/bands/of/${id}`);
}

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

type PickedArtist = { id: string; name: string; roles: string[] };
type PendingRole = { type: string; custom: string };
const DEFAULT_PENDING: PendingRole = { type: ARTIST_ROLES[0], custom: "" };

export default function BandNew() {
  const { artists } = useLoaderData<typeof loader>();
  const actionData = useActionData<typeof action>();
  const errors = actionData?.errors ?? {};

  const [name, setName] = useState("");
  const [slug, setSlug] = useState("");
  const [slugManual, setSlugManual] = useState(false);
  const [links, setLinks] = useState<{ label: string; url: string }[]>([]);
  const [picked, setPicked] = useState<PickedArtist[]>([]);
  const [pending, setPending] = useState<Record<string, PendingRole>>({});

  const available = artists.filter((a) => !picked.some((p) => p.id === a.id));

  function addRole(artistId: string) {
    const pend = pending[artistId] ?? DEFAULT_PENDING;
    const role = pend.type === "other" ? pend.custom.trim() : pend.type;
    if (!role) return;
    setPicked((prev) => prev.map((a) => a.id === artistId ? { ...a, roles: [...a.roles, role] } : a));
  }

  function removeRole(artistId: string, idx: number) {
    setPicked((prev) => prev.map((a) => a.id === artistId ? { ...a, roles: a.roles.filter((_, i) => i !== idx) } : a));
  }

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

      <Form method="post">
        <input type="hidden" name="links" value={JSON.stringify(links)} />
        <input
          type="hidden"
          name="artists"
          value={JSON.stringify(picked.map((p) => ({ id: p.id, role: p.roles.join(", ") || null })))}
        />

        <div>
          <label>バンド名 <span className="req">*</span></label>
          <input
            name="name"
            value={name}
            onChange={(e) => { setName(e.target.value); if (!slugManual) setSlug(toSlug(e.target.value)); }}
          />
          {errors.name && <p className="error">{errors.name}</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>活動拠点</label>
          <input name="area" />
        </div>

        <div>
          <label>ステータス</label>
          <select name="status" defaultValue="active">
            <option value="active">活動中</option>
            <option value="hiatus">活動休止</option>
            <option value="disbanded">解散</option>
          </select>
        </div>

        <div>
          <label>説明</label>
          <textarea name="description" rows={3} />
        </div>

        <div>
          <label>リンク</label>
          <div className="links-form">
            {links.map((link, i) => (
              <div key={i} className="link-row">
                <select
                  value={link.label}
                  onChange={(e) => setLinks(links.map((l, idx) => idx === i ? { ...l, label: e.target.value } : l))}
                >
                  {LINK_TYPES.map((t) => <option key={t.value} value={t.value}>{t.label}</option>)}
                </select>
                <input
                  value={link.url}
                  onChange={(e) => setLinks(links.map((l, idx) => idx === i ? { ...l, url: e.target.value } : l))}
                  placeholder="https://..."
                />
                <button type="button" className="btn-icon" onClick={() => setLinks(links.filter((_, idx) => idx !== i))}>×</button>
              </div>
            ))}
          </div>
          <button
            type="button"
            className="btn-text"
            onClick={() => setLinks([...links, { label: LINK_TYPES[0].value, url: "" }])}
          >
            + リンクを追加
          </button>
        </div>

        <div>
          <label>メンバー</label>
          {picked.length > 0 && (
            <div className="members-form">
              {picked.map((p) => {
                const pend = pending[p.id] ?? DEFAULT_PENDING;
                return (
                  <div key={p.id} className="member-card">
                    <div className="card-header">
                      <span className="card-name">{p.name}</span>
                      <button
                        type="button"
                        className="btn-icon"
                        onClick={() => setPicked(picked.filter((a) => a.id !== p.id))}
                      >
                        削除
                      </button>
                    </div>
                    {p.roles.length > 0 && (
                      <div className="badges">
                        {p.roles.map((r, ri) => (
                          <span key={ri} className="badge">
                            {r}
                            <button type="button" onClick={() => removeRole(p.id, ri)}>×</button>
                          </span>
                        ))}
                      </div>
                    )}
                    <div className="role-row">
                      <select
                        value={pend.type}
                        onChange={(e) => setPending({ ...pending, [p.id]: { ...pend, type: e.target.value } })}
                      >
                        {ARTIST_ROLES.map((r) => <option key={r} value={r}>{r}</option>)}
                        <option value="other">その他...</option>
                      </select>
                      {pend.type === "other" && (
                        <input
                          className="custom-input"
                          value={pend.custom}
                          onChange={(e) => setPending({ ...pending, [p.id]: { ...pend, custom: e.target.value } })}
                          placeholder="ロール名"
                        />
                      )}
                      <button type="button" className="btn-text" onClick={() => addRole(p.id)}>+ 追加</button>
                    </div>
                  </div>
                );
              })}
            </div>
          )}
          {available.length > 0 ? (
            <select
              onChange={(e) => {
                const a = artists.find((x) => x.id === e.target.value);
                if (a) {
                  setPicked([...picked, { id: a.id, name: a.name, roles: [] }]);
                  setPending({ ...pending, [a.id]: { ...DEFAULT_PENDING } });
                  e.target.value = "";
                }
              }}
              defaultValue=""
            >
              <option value="">+ アーティストを追加...</option>
              {available.map((a) => <option key={a.id} value={a.id}>{a.name}</option>)}
            </select>
          ) : artists.length === 0 ? (
            <p className="muted">
              アーティストがいません。{" "}
              <Link to="/artists/new">先に作成</Link>
            </p>
          ) : null}
        </div>

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

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