/* =============================================================================
 * M01_MasterData_UI_Logic_Wizard_Source.ts
 * 만들기 둘째 걸음 — 원문 절 고르기(책 → 부문 → 장 → 절) · 그 절(아래 절 포함)의 표를 용도와 함께 제시
 * 절 목록 = `GET /sections` · 표 = `GET /tables?section=` — 번호를 손으로 넣지 않음
 * ========================================================================== */

import { el } from "@ui/ui_template_elements";
import {
  fetchSections,
  fetchSectionTables,
  type SectionBrief,
  type TableBrief,
} from "./M01_MasterData_UI_Logic_Wizard_Api";
import { select, textBox } from "./M01_MasterData_UI_Logic_Wizard_Atom";
import type { Draft } from "./M01_MasterData_UI_Logic_Wizard_Model";
import { tw } from "./M01_MasterData_UI_Logic_Wizard_Text";
import { fail, note, page, type Step } from "./M01_MasterData_UI_Logic_Wizard_Ui";

const sections = new Map<string, Promise<SectionBrief[]>>();
const load = (book: string): Promise<SectionBrief[]> => {
  let got = sections.get(book);
  if (!got) sections.set(book, (got = fetchSections(book)));
  return got;
};

const distinct = (rows: SectionBrief[], key: "division" | "chapter"): string[] => [
  ...new Set(rows.map((r) => r[key]).filter(Boolean)),
];

export const sourceStep: Step = {
  key: "S_Source",
  question: "Q_Source",
  ready: (d) => d.section.trim() !== "",
  render: ({ d, changed }) => {
    const filters = el("div", { className: "m01w__inline" });
    const list = el("div", { className: "m01w__found" });
    const picked = el("p", { className: "m01w__picked" });
    const tables = el("div", { className: "m01w__stack" });
    let all: SectionBrief[] = [];
    let division = "";
    let chapter = "";
    let q = "";

    const drawTables = (): void =>
      tables.replaceChildren(
        ...(d.section && !d.tables.length
          ? [note(tw("Section_None")), note(tw("Section_Skip"))]
          : d.tables.map((t) => tableRow(t, d, changed))),
      );

    const choose = (s: SectionBrief): void => {
      d.section = s.section;
      d.tables = [];
      picked.textContent = `${tw("Section_Picked")} · ${s.section} ${s.title}`;
      changed();
      drawList();
      void fetchSectionTables(d.book, s.section)
        .then((found) => {
          d.tables = [...found]; // 처음에는 이 절의 표를 모두 씀 — 빼려면 체크를 풂
          drawTables();
          changed();
        })
        .catch(fail);
    };

    const options = (values: string[]): { value: string; text: string }[] =>
      values.map((v) => ({ value: v, text: v }));

    const draw = (): void => {
      const inDivision = all.filter((s) => !division || s.division === division);
      const chapters = distinct(inDivision, "chapter");
      if (!chapters.includes(chapter)) chapter = chapters[0] ?? "";
      const divisions = distinct(all, "division");
      filters.replaceChildren(
        select(
          ["산림품셈", "건설품셈"].map((b) => ({ value: b, text: b })),
          d.book,
          (v) => {
            d.book = v;
            d.section = "";
            d.tables = [];
            division = chapter = "";
            picked.textContent = "";
            drawTables();
            changed();
            start();
          },
          tw("Book"),
        ),
        ...(divisions.length
          ? [
              select(
                options(divisions),
                division || divisions[0],
                (v) => ((division = v), (chapter = ""), draw()),
                tw("Division"),
              ),
            ]
          : []),
        select(options(chapters), chapter, (v) => ((chapter = v), draw()), tw("Chapter")),
        textBox(q, tw("Section_Search"), (v) => ((q = v.trim()), drawList())),
      );
      drawList();
    };

    const drawList = (): void => {
      const inChapter = all.filter(
        (s) =>
          (!division || s.division === division) &&
          s.chapter === chapter &&
          (!q || s.section.startsWith(q) || s.title.includes(q)),
      );
      list.replaceChildren(
        ...inChapter.slice(0, 80).map((s) => {
          const row = el("button", {
            className: `m01w__row${s.section === d.section ? " is-active" : ""}`,
            attrs: { type: "button", "data-section": s.section },
            text: `${s.section} ${s.title} · ${tw("Section_Counts", { t: s.tables, l: s.logics })}`,
          });
          row.addEventListener("click", () => choose(s));
          return row;
        }),
      );
    };

    const start = (): void => {
      void load(d.book)
        .then((rows) => {
          all = rows;
          const divisions = distinct(rows, "division");
          division = divisions[0] ?? "";
          const own = rows.find((s) => s.section === d.section);
          if (own) {
            division = own.division;
            chapter = own.chapter;
            picked.textContent = `${tw("Section_Picked")} · ${own.section} ${own.title}`;
          }
          draw();
        })
        .catch(fail);
    };
    start();
    drawTables();
    return page("Q_Source", filters, list, picked, tables);
  },
};

function tableRow(t: TableBrief, d: Draft, changed: () => void): HTMLElement {
  const check = el("input", { attrs: { type: "checkbox", "data-table": t.키 } });
  check.checked = d.tables.some((x) => x.키 === t.키);
  check.addEventListener("change", () => {
    d.tables = check.checked ? [...d.tables, t] : d.tables.filter((x) => x.키 !== t.키);
    changed();
  });
  const usage = t.용도?.대상?.join("·") ?? "";
  return el("label", {
    className: "m01w__table",
    children: [
      check,
      el("div", {
        className: "m01w__stack",
        children: [
          el("strong", { text: `${t.원문번호} ${t.이름} · ${t.키}` }),
          el("span", {
            className: "m01w__muted",
            text: [
              t.기준 ? `${tw("Table_Base")} ${t.기준}` : "",
              `${tw("Table_Cols")} ${Object.keys(t.값칸 ?? {}).join("·")}`,
              usage ? `${tw("Table_Usage")} ${usage}` : "",
            ]
              .filter(Boolean)
              .join(" · "),
          }),
        ],
      }),
    ],
  });
}