import { useEffect, useRef, useState, type FormEvent } from "react";

import type {
  CreateDocumentInput,
  RecordKind,
} from "../../../contracts/studio/contract.ts";
import { createLocalId } from "../../../domain/studio/local-id.ts";
import { useStudio } from "../use-studio.ts";

const types = [
  {
    kind: "CASE",
    title: "Case",
    description: "문제를 재현하고 검증한 결론을 기록합니다.",
    fields: "문제 · 결론 · 환경 · 재현 · 본문",
  },
  {
    kind: "REFERENCE",
    title: "Reference",
    description: "반복해서 적용할 기술 기준을 정리합니다.",
    fields: "목적 · 규칙 · 적용 조건 · 예외 · 예시",
  },
  {
    kind: "QUESTION",
    title: "Question",
    description: "아직 닫히지 않은 판단과 다음 검증을 관리합니다.",
    fields: "상태 · 사실 · 가정 · 미지수 · 선택지",
  },
  {
    kind: "PROJECT_DECISION",
    title: "Decision",
    description: "프로젝트가 선택한 방향과 그 근거·영향을 기록합니다.",
    fields: "상태 · 결정일 · 결정문 · 판단 이유 · 영향 · 근거",
  },
] as const;

function emptyDocument(kind: RecordKind): CreateDocumentInput {
  const common = {
    title: "",
    slug: "" as const,
    summary: "",
    topicId: null,
    projectId: null,
    relations: [],
  };
  if (kind === "CASE") {
    return {
      ...common,
      kind,
      problem: "",
      conclusion: "",
      environment: "",
      reproduction: "",
      lastVerifiedOn: null,
      bodyMarkdown: "",
    };
  }
  if (kind === "REFERENCE") {
    return {
      ...common,
      kind,
      purpose: "",
      rules: [],
      applyWhen: [],
      exceptions: [],
      examples: [],
      verifiedOn: null,
    };
  }
  if (kind === "QUESTION") {
    return {
      ...common,
      kind,
      questionStatus: null,
      facts: [],
      assumptions: [],
      unknowns: [],
      constraints: [],
      options: [],
      nextValidation: "",
      resolution: null,
    };
  }
  return {
    ...common,
    kind,
    decisionStatus: null,
    decidedOn: null,
    statement: "",
    rationale: "",
    consequences: [],
  };
}

function isAbortError(error: unknown): boolean {
  return error instanceof DOMException && error.name === "AbortError";
}

export function NewDocumentForm() {
  const { gateway, navigateInternal, setRequestAnnouncement } = useStudio();
  const [kind, setKind] = useState<RecordKind>("CASE");
  const [pending, setPending] = useState(false);
  const [error, setError] = useState("");
  const locked = useRef(false);
  const activeRequest = useRef<AbortController | null>(null);

  useEffect(() => () => activeRequest.current?.abort(), []);

  const submit = async (event: FormEvent) => {
    event.preventDefault();
    if (locked.current) return;
    locked.current = true;
    setPending(true);
    setError("");
    const controller = new AbortController();
    activeRequest.current = controller;
    try {
      const document = await gateway.createDocument(emptyDocument(kind), {
        idempotencyKey: createLocalId("studio-create"),
        signal: controller.signal,
      });
      setRequestAnnouncement(
        `${types.find((type) => type.kind === kind)?.title} 작업본을 만들었습니다.`,
      );
      navigateInternal(`/studio/documents/${document.id}/edit`);
    } catch (reason) {
      if (!isAbortError(reason)) {
        setError("작업본을 만들지 못했습니다. 다시 시도해 주세요.");
      }
    } finally {
      if (activeRequest.current === controller) activeRequest.current = null;
      locked.current = false;
      setPending(false);
    }
  };

  return (
    <div className="studio-page studio-new-page">
      <header className="studio-page-heading">
        <p className="studio-eyebrow">NEW WORKING COPY</p>
        <h1>새 문서</h1>
        <p>
          목적에 맞는 기록 종류를 선택하면 빈 작업본을 만들고 바로 편집을 시작합니다.
        </p>
      </header>
      <form
        onSubmit={(event) => {
          void submit(event);
        }}
      >
        <fieldset className="studio-type-list">
          <legend>문서 종류</legend>
          {types.map((type) => (
            <label key={type.kind}>
              <input
                type="radio"
                name="kind"
                value={type.kind}
                checked={kind === type.kind}
                onChange={() => setKind(type.kind)}
              />
              <strong>{type.title}</strong>
              <span>{type.description}</span>
              <small>{type.fields}</small>
            </label>
          ))}
        </fieldset>
        <div className="studio-create-footer">
          <button className="studio-primary-button" type="submit" disabled={pending}>
            {pending ? "만드는 중…" : "작업본 만들기"}
          </button>
          <p>이 화면의 작업본은 현재 Studio 세션에서만 유지됩니다.</p>
        </div>
        {error ? (
          <p className="studio-screen-error" role="alert">
            {error}
          </p>
        ) : null}
      </form>
    </div>
  );
}