/* =============================================================================
 * ui_template_sheet_render.ts
 * 표 그리기 — 문서 + 풀이 결과 → 쪽마다 `<table>`(머리 층 · 단위 줄 · 본문 · 합계 줄).
 *
 * 칸마다 `data-r`(줄 열쇠) · `data-c`(열 id) — 고치기 · 키보드는 격자(`ui_template_sheet.ts`)가 위임으로 받음.
 * 줄 열쇠 — 본문 `d:<줄id>` · 합계 `t:<합계id>` · 마스터 줄 `s:unit|formula|desc|price`.
 * master = 값 대신 열마다 식 · 들어갈 것 · 일위대가 줄 · project = 쪽줄마다 쪽을 나눔(쪽마다 머리 · 합계는 마지막 쪽).
 * ========================================================================== */

import { el } from "@ui/ui_template_elements";
import { headDepth, layoutHead } from "./ui_template_sheet_header";
import {
  cellEditable,
  isBoundColumn,
  isCalcColumn,
  orderedRows,
  type SheetMode,
} from "./ui_template_sheet_ops";
import { groupDigits, totalFormula } from "./ui_template_sheet_recalc";
import { st } from "./ui_template_sheet_text";
import type { SheetColumn, SheetDoc, SheetResult, SheetRow } from "./ui_template_sheet_types";

export const KEY_UNIT = "s:unit";
const MASTER_ROWS = ["s:formula", "s:desc", "s:price"] as const;
const GUTTER = 48;
const DEFAULT_WIDTH = { 수: 72, 글: 96 };
const PAGE_ROWS = 50;

export interface RenderState {
  doc: SheetDoc;
  mode: SheetMode;
  result: SheetResult;
  sel: { r: string; c: string } | null;
}

export const columnWidth = (doc: SheetDoc, col: SheetColumn): number =>
  doc.보기?.열너비?.[col.id] ?? DEFAULT_WIDTH[col.꼴 === "글" ? "글" : "수"];

/** 키보드로 옮겨 다니는 줄 차례(쪽을 가로지름). */
export function navRows(doc: SheetDoc, mode: SheetMode): string[] {
  const special = mode === "master" ? [KEY_UNIT, ...MASTER_ROWS] : [KEY_UNIT];
  return [
    ...special,
    ...orderedRows(doc).map((r) => `d:${r.id}`),
    ...(doc.합계줄 ?? []).map((t) => `t:${t.id}`),
  ];
}

/** 칸을 고칠 수 있나 — 줄 열쇠 기준(머리 칸은 따로). */
export function keyEditable(state: RenderState, key: string, col: SheetColumn): boolean {
  if (key.startsWith("s:")) return state.mode === "master";
  if (key.startsWith("t:")) return false;
  const row = state.doc.줄.find((r) => `d:${r.id}` === key);
  return !!row && cellEditable(state.mode, col, row);
}

const shown = (text: string | undefined): string =>
  !text || text === "0" ? "" : groupDigits(text);

function kindOf(col: SheetColumn): { cls: string; label: string } | null {
  if (isBoundColumn(col)) return { cls: "is-bound", label: st("Kind_Bound") };
  if (isCalcColumn(col)) return { cls: "is-calc", label: st("Kind_Calc") };
  if (col.손) return { cls: "is-hand", label: st("Kind_Hand") };
  return null;
}

export function renderSheet(state: RenderState): HTMLElement {
  const { doc, mode } = state;
  const cols = doc.열;
  const depth = headDepth(cols, doc.층);
  const head = layoutHead(cols, depth);
  const errors = new Map(state.result.오류.map((e) => [`d:${e.줄}|${e.열}`, e.까닭]));
  for (const e of state.result.오류) errors.set(`t:${e.줄}|${e.열}`, e.까닭);
  const frozen = Math.min(doc.보기?.틀고정?.열 ?? 0, cols.length);
  const lefts: number[] = [];
  let left = GUTTER;
  for (const col of cols) {
    lefts.push(left);
    left += columnWidth(doc, col);
  }

  const freeze = (cell: HTMLElement, from: number, span = 1): void => {
    if (from + span > frozen) return;
    cell.classList.add("is-frozen");
    cell.style.left = `${lefts[from]}px`;
  };
  const gutter = (tag: "th" | "td", text: string, cls = ""): HTMLElement =>
    el(tag, { className: `ui-sheet__gutter ${cls}`.trim(), text });

  const bodyCell = (key: string, col: SheetColumn, j: number, text: string): HTMLElement => {
    const td = el("td", { text, attrs: { "data-r": key, "data-c": col.id } });
    const kind = kindOf(col);
    if (kind) td.classList.add(kind.cls);
    if (col.꼴 !== "글") td.classList.add("is-num");
    td.classList.add(keyEditable(state, key, col) ? "is-editable" : "is-locked");
    const why = errors.get(`${key}|${col.id}`);
    if (why) {
      td.classList.add("is-error");
      td.textContent = st("Error");
      td.title = why;
    } else if (text) td.title = text;
    if (state.sel?.r === key && state.sel.c === col.id) td.classList.add("is-selected");
    freeze(td, j);
    return td;
  };

  const dataRow = (row: SheetRow, n: number): HTMLElement => {
    const key = `d:${row.id}`;
    const tr = el("tr", { children: [gutter("th", String(n))] });
    if (row.고정) tr.classList.add("is-fixed");
    cols.forEach((col, j) => {
      const formula = row.식?.[col.id] ?? col.식;
      const raw = row.값[col.id];
      const text = formula
        ? shown(state.result.계산[row.id]?.[col.id])
        : raw === null || raw === undefined
          ? ""
          : col.꼴 !== "글" && typeof raw === "number"
            ? groupDigits(String(raw))
            : String(raw);
      const td = bodyCell(key, col, j, text);
      if (row.식?.[col.id]) td.classList.add("is-override");
      tr.append(td);
    });
    return tr;
  };

  const masterRow = (key: (typeof MASTER_ROWS)[number]): HTMLElement => {
    const label = { "s:formula": "Row_Formula", "s:desc": "Row_Desc", "s:price": "Row_Unit_Price" }[
      key
    ] as "Row_Formula" | "Row_Desc" | "Row_Unit_Price";
    const tr = el("tr", { className: "ui-sheet__meta", children: [gutter("th", st(label))] });
    cols.forEach((col, j) => {
      const text =
        key === "s:formula"
          ? (col.식 ?? "")
          : key === "s:desc"
            ? (col.설명 ?? "")
            : (col.일위대가 ?? "");
      const td = bodyCell(key, col, j, text);
      td.classList.remove("is-num");
      const kind = kindOf(col);
      if (key === "s:desc" && kind) {
        const chip = el("span", {
          className: `ui-sheet__chip ${kind.cls}`,
          text: col.펼침 ? `${kind.label} · ${st("Kind_Spread")}` : kind.label,
        });
        td.prepend(chip);
      }
      tr.append(td);
    });
    return tr;
  };

  const thead = (): HTMLElement => {
    const rows = head.map((cells, level) => {
      const tr = el("tr", { children: [gutter("th", doc.층?.[level] ?? "")] });
      for (const cell of cells) {
        const th = el("th", {
          text: cell.label,
          attrs: {
            colspan: String(cell.colspan),
            rowspan: String(cell.rowspan),
            "data-level": String(cell.level),
            "data-col": cols[cell.col].id,
          },
        });
        if (mode === "master") th.classList.add("is-editable");
        freeze(th, cell.col, cell.colspan);
        tr.append(th);
      }
      return tr;
    });
    const unit = el("tr", {
      className: "ui-sheet__unit",
      children: [gutter("th", st("Row_Unit"))],
    });
    cols.forEach((col, j) => {
      const th = bodyCell(KEY_UNIT, col, j, col.단위 ?? "");
      th.classList.remove("is-num");
      th.append(el("span", { className: "ui-sheet__resize", attrs: { "data-resize": col.id } }));
      unit.append(th);
    });
    return el("thead", { children: [...rows, unit] });
  };

  const totalRows = (): HTMLElement[] =>
    (doc.합계줄 ?? []).map((total) => {
      const tr = el("tr", { className: "ui-sheet__total", children: [gutter("th", total.이름)] });
      cols.forEach((col, j) => {
        const td = bodyCell(`t:${total.id}`, col, j, shown(state.result.합계[total.id]?.[col.id]));
        if (totalFormula(total, col)) td.title = totalFormula(total, col)!;
        tr.append(td);
      });
      return tr;
    });

  const colgroup = el("colgroup", {
    children: [
      el("col", { attrs: { style: `width:${GUTTER}px` } }),
      ...cols.map((col) =>
        el("col", { attrs: { style: `width:${columnWidth(doc, col)}px`, "data-col": col.id } }),
      ),
    ],
  });

  const data = orderedRows(doc);
  const size = mode === "project" ? Math.max(1, doc.쪽줄 ?? PAGE_ROWS) : Math.max(1, data.length);
  const pageCount = Math.max(1, Math.ceil(data.length / size));
  const pages: HTMLElement[] = [];
  for (let p = 0; p < pageCount; p += 1) {
    const slice = data.slice(p * size, (p + 1) * size);
    const body = el("tbody", {
      children: [
        ...(mode === "master" && p === 0 ? MASTER_ROWS.map(masterRow) : []),
        ...slice.map((row, i) => dataRow(row, p * size + i + 1)),
        ...(p === pageCount - 1 ? totalRows() : []),
      ],
    });
    const table = el("table", {
      className: "ui-sheet__table",
      attrs: { style: `width:${left}px` },
      children: [colgroup.cloneNode(true) as HTMLElement, thead(), body],
    });
    if (pageCount > 1) {
      table.prepend(
        el("caption", {
          text: `${p + 1} / ${pageCount} ${st("Page")}`,
          className: "ui-sheet__page",
        }),
      );
    }
    pages.push(table);
  }
  return el("div", { className: "ui-sheet__pages", children: pages });
}