/* =============================================================================
 * B02_ProjRegister_UI_Page.ts
 * 로그인 후 02: 프로젝트 등록 (신규 임도 설계 프로젝트 기본 정보 입력)
 *
 * 제약 준수 (frontend.md):
 *   - 모든 문구는 ui_template_locale.ts 참조 (하드코딩 금지, §3).
 *   - 색상/간격은 theme.css 변수 + 공통 컴포넌트만 사용 (§1, §2).
 *   - 이벤트 핸들러는 onB02_[기능]_[액션] 명명 (§4).
 *   - 백엔드 전송 전 1차 유효성 검사 (§4).
 * ========================================================================== */

import { ui_locales, currentLanguageIndex } from "@ui/ui_template_locale";
import {
  createButton,
  createInputField,
  createSelectField,
  createCard,
  hideLoadingOverlay,
  showLoadingOverlay,
  showToast,
} from "@ui/ui_template_elements";
import { isBlank } from "@util/common_util_validate";
import { navigateTo } from "../A00_Common/router";
import { API_BASE_URL, CURRENT_PROJECT_ID_KEY, ROUTES } from "@config/config_frontend";
import "./B02_ProjRegister_UI_Style.css";

/** locale 헬퍼 */
function L(key: keyof typeof ui_locales): string {
  return ui_locales[key][currentLanguageIndex];
}

/* -----------------------------------------------------------------------------
 * 페이지 진입점
 * -------------------------------------------------------------------------- */
export function renderB02ProjRegister(root: HTMLElement): void {
  const page = document.createElement("div");
  page.className = "b02-proj";

  const header = document.createElement("div");
  header.className = "b02-proj__header";
  const title = document.createElement("h1");
  title.className = "b02-proj__title";
  title.textContent = L("B02_Proj_Title");
  const subtitle = document.createElement("p");
  subtitle.className = "b02-proj__subtitle";
  subtitle.textContent = L("B02_Proj_Subtitle");
  header.append(title, subtitle);

  // 입력 필드
  const nameField = createInputField({
    label: L("B02_Proj_Field_Name"),
    placeholder: L("B02_Proj_Field_Name_Placeholder"),
    required: true,
  });
  const regionField = createInputField({
    label: L("B02_Proj_Field_Region"),
    placeholder: L("B02_Proj_Field_Region_Placeholder"),
    required: true,
  });
  const roadTypeField = createSelectField({
    label: L("B02_Proj_Field_RoadType"),
    options: [
      { value: "main", text: L("B02_Proj_RoadType_Main") },
      { value: "branch", text: L("B02_Proj_RoadType_Branch") },
      { value: "fire", text: L("B02_Proj_RoadType_Fire") },
      { value: "stream", text: L("B02_Proj_RoadType_Stream") },
    ],
  });
  const currentYear = new Date().getFullYear();
  const yearField = createInputField({
    label: L("B02_Proj_Field_Year"),
    type: "number",
    value: String(currentYear),
    min: 2000,
    max: currentYear + 5,
  });
  const lengthField = createInputField({
    label: L("B02_Proj_Field_Length"),
    placeholder: L("B02_Proj_Field_Length_Placeholder"),
    type: "number",
    min: 0,
  });
  const memoField = createInputField({
    label: L("B02_Proj_Field_Memo"),
    placeholder: L("B02_Proj_Field_Memo_Placeholder"),
    type: "text",
  });

  const submitBtn = createButton({
    label: L("B02_Proj_Submit"),
    variant: "filled",
    onClick: onB02_Proj_Submit_Click,
  });
  submitBtn.classList.add("b02-proj__submit");

  async function onB02_Proj_Submit_Click(): Promise<void> {
    nameField.setError();
    regionField.setError();
    yearField.setError();
    lengthField.setError();

    // 1차 유효성: 필수값 검사
    let hasError = false;
    const projectYear = Number.parseInt(yearField.input.value, 10);
    const estimatedLength = isBlank(lengthField.input.value)
      ? null
      : Number.parseFloat(lengthField.input.value);
    if (isBlank(nameField.input.value)) {
      nameField.setError(L("B02_Proj_Error_Required"));
      hasError = true;
    }
    if (isBlank(regionField.input.value)) {
      regionField.setError(L("B02_Proj_Error_Required"));
      hasError = true;
    }
    if (!Number.isInteger(projectYear) || projectYear < 2000 || projectYear > 2100) {
      yearField.setError(L("Common_Validation_NumberRange"));
      hasError = true;
    }
    if (estimatedLength !== null && (!Number.isFinite(estimatedLength) || estimatedLength < 0)) {
      lengthField.setError(L("Common_Validation_NumberRange"));
      hasError = true;
    }
    if (hasError) return;

    showLoadingOverlay();
    try {
      const response = await fetch(`${API_BASE_URL}/b02/project`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        credentials: "include",
        body: JSON.stringify({
          name: nameField.input.value.trim(),
          region: regionField.input.value.trim(),
          road_type: roadTypeField.select.value,
          project_year: projectYear,
          estimated_length_m: estimatedLength,
          memo: memoField.input.value.trim() || null,
        }),
      });

      if (!response.ok) {
        let detail = L("Common_Status_Error");
        try {
          const errorBody = (await response.json()) as { detail?: string; message?: string };
          detail = errorBody.detail ?? errorBody.message ?? detail;
        } catch {
          detail = `${detail} (${response.status})`;
        }
        throw new Error(detail);
      }

      const data = (await response.json()) as { project_id: string };
      localStorage.setItem(CURRENT_PROJECT_ID_KEY, data.project_id);
      showToast(L("B02_Proj_Success"), "success");
      navigateTo(ROUTES.B03_FILE_INPUT);
    } catch (error) {
      const message = error instanceof Error ? error.message : L("Common_Status_Error");
      showToast(message, "error");
    } finally {
      hideLoadingOverlay();
    }
  }

  const grid = document.createElement("div");
  grid.className = "b02-proj__grid";
  grid.append(
    nameField.root,
    regionField.root,
    roadTypeField.root,
    yearField.root,
    lengthField.root,
    memoField.root,
  );

  const card = createCard({ body: [grid, submitBtn], raised: true });
  page.append(header, card);
  root.append(page);
}